JP4452367B2 - Position control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a control device that performs position control of a mechanical system using a torque generator such as an electric motor in a machine tool or the like.
[0002]
[Prior art]
  In a position control device that controls the position of a machine tool or the like using a torque generator such as a motor, in order to realize high-speed and high-accuracy positioning control, control that does not excite machine resonance is desired. When overshoot occurs, the settling time becomes longer due to the effect of Coulomb friction, so control that does not cause overshoot is desired. Moreover, in such a position control device, the follow-up performance with respect to the position command is increased by using feedforward.
[0003]
  FIG. 12 shows, for example, “Measurement and Control” vol. 12, p. 1010-p. 1 is a block diagram showing a configuration of a first conventional position control apparatus described in 1011. FIG. In FIG. 12, reference numeral 1 denotes a control target that drives a mechanical system by generating torque according to a torque command τr. Reference numeral 2 denotes a position detector that detects an actual position xm that is the position of the control object 1. A speed detector 3 detects an actual speed vm which is a differential signal of the actual position xm. Reference numeral 4 denotes a model signal calculation unit that inputs a position command xr and outputs a model position xa, a model speed va, and a model torque τa. Reference numeral 505 denotes a torque command calculation unit. Reference numeral 506 denotes a position compensator. Reference numeral 507 denotes a speed PI compensator.
  Next, the operation of the first prior art shown in FIG. 12 will be described. First, the characteristics of the controlled object 1 will be described. If the generated torque in the controlled object 1 ideally matches the torque command τr, and the transfer characteristic of the controlled object 1 is described as G (s), the relationship between the torque command τr and the disturbance torque τd and the actual position xm is as follows: It is represented by Formula 1 of However, s represents a Laplace operator in the following formula and the following.
  xm = G (s) · τr + G (s) · τd (Equation 1)
[0004]
  Further, assuming that the controlled object 1 is a complete rigid machine, the transfer characteristic G (s) of the controlled object 1 is expressed by the following equation 2.
  G (s) = 1 / (J · s²) (Formula 2)
[0005]
  However, there are model errors such as mechanical resonance and friction in the actual controlled object. For example, the transfer characteristic G (s) of the controlled object when viscous friction with the friction coefficient f exists is expressed by the following equation (3).
  G (s) = 1 / (J · s²+ F · s) (Formula 3)
[0006]
  Next, the operation of the model signal calculation unit 4 will be described. The model signal calculation unit 4 receives a position command xr given to the position control device from the outside, and is a model position xa based on the transfer function calculation of the model transfer characteristic Ga (s), which is a low-pass characteristic, and a differential signal of the model position xa. The model speed va, a model acceleration aa that is a differential signal of the model speed va, and a model torque τa that is a signal obtained by multiplying the model acceleration aa by a model inertia Ja that is an inertia value of a control object that is estimated in advance are calculated. The model position xa, model speed va, and model torque τa are output.
[0007]
  Here, when there is no disturbance torque τd and the characteristic of the controlled object 1 is an ideal rigid machine and its inertia J matches the model inertia Ja (hereinafter, this is described as an ideal model), the above model torque If the controlled object 1 is driven using τa, the actual position xm and the model position xa of the controlled object 1 and the actual speed vm and the model speed va are completely matched, and the transfer characteristic from the position command xr to the actual position xm is It matches the model transfer characteristic Ga (s). That is, the following formula 4 is established.
  xm / xr = xa / xr = Ga (s) (4)
[0008]
  Next, the operation of the torque command calculation unit 505 will be described. Since there are disturbances and model errors in the actual controlled object 1, errors occur between the actual position xm and the model position xa and between the actual speed vm and the model speed va. The position compensator 506 outputs a signal obtained by multiplying the difference between the model position xa and the actual position xm by a position gain ωx, and the speed PI compensator 507 outputs the difference signal between the model speed va and the actual speed vm to the output of the position compensator 506. Is input, and a PI (proportional integration) calculation of the speed proportional gain Kv and the integral gain ωPI is performed to output an error compensation torque τc. The torque command calculation unit 505 outputs a sum signal of the model torque τa and the error compensation torque τc as the torque command τr. That is, the torque command calculation unit 505 calculates the torque command τr by the calculation of Equation 5 below.
  τr = τa + Kv · (1 + ωPI / s) {va−vm + ωx (xa−xm)}
    ... (Formula 5)
[0009]
  The torque command calculation unit 505 outputs the sum signal of the model torque τa and the error compensation torque τc as the torque command τr, so that when the control target 1 is an ideal model, only the model torque τa or the control target When there is a model error in 1, the control object 1 is driven by adding the error compensation torque τc so that the actual position xm follows the model position xa.
[0010]
  In addition, since the model transfer characteristic Ga (s) has a low-pass characteristic, if there is a high-frequency model error such as mechanical resonance in the controlled object 1, the response of the model transfer characteristic Ga (s) is delayed, that is, the low-pass characteristic. By reducing the cut-off frequency, mechanical resonance is suppressed, and as a result, high-speed settling can be realized.
[0011]
  As described above, the first conventional technique suppresses mechanical resonance in a relatively high frequency range (several tens of Hz) by using the model transfer characteristic Ga (s) as a low-pass characteristic. However, if an attempt is made to suppress overshoot in anticipation of the low-pass characteristic of the model transfer characteristic Ga (s), this overshoot is a phenomenon in a lower frequency range (about several Hz or less). If the characteristic Ga (s) is a characteristic matched to this, the control response becomes very slow, and it is difficult to realize the control that settles at high speed.
[0012]
  Next, FIG. 13 is a control system configuration diagram of a second prior art described in, for example, Japanese Patent Laid-Open No. 05-216540. In FIG. 13, a discrete time control system is converted into a continuous time system and equivalently described. 13, the same reference numerals as those in FIG. 12 denote the same parts. Reference numeral 605 denotes a torque command calculation unit. Reference numeral 606 denotes a position compensator, and reference numeral 607 denotes a speed PI compensator. 612 is a torque feedforward amplifier, and 611 is a speed feedforward amplifier. Reference numeral 608 denotes a first differentiator, 609 denotes a second differentiator, and 610 denotes an inertial amplifier.
[0013]
  Next, the operation of the second prior art will be described. Description of the operation of the same parts as those of the first prior art is omitted. The first differentiator 608 differentiates the position command xr and outputs a speed command vr, the second differentiator 609 differentiates the speed command vr and outputs an acceleration command ar, and the inertia amplifier 610 responds to the acceleration command ar. A model torque τa obtained by multiplying a preset estimated value Ja of the inertia of the control target 1 is output.
[0014]
  Next, the operation of the torque command calculation unit 605 will be described. The torque command calculation unit 605 inputs the position command xr, the speed command vr, the model torque τa, the actual speed vm, and the actual position xm. Inside the torque command calculation unit 605, the torque feedforward amplifier 612 outputs a feedforward torque τf obtained by multiplying the model torque τa by the torque feedforward gain ατ, and the speed feedforward amplifier 611 outputs the speed feedforward gain αv to the speed command vr. The multiplied feed forward speed vf is output.
[0015]
  Next, the position compensator 606 outputs a signal obtained by multiplying the difference signal between the position command xr and the actual position xm by the position gain ωx, and the speed PI compensator 607 outputs a position signal based on the difference signal between the feedforward speed vf and the actual speed vm. A signal obtained by adding the output of the compensator 606 is input, and a PI (proportional integration) calculation of the speed proportional gain Kv and the integral gain ωPI is performed to output an error compensation torque τc. The torque command calculation unit 605 outputs a sum signal of the model torque τa and the error compensation torque τc as the torque command τr. That is, the torque command calculation unit 605 calculates the torque command τr by the calculation of Equation 6 below.
  τr = ατ · τa + Kv · (1 + ωPI / s) {αv · vr−vm + ωx (xr−xm)} (Expression 6)
[0016]
  The second prior art is configured as described above, and when the torque feedforward gain ατ and the speed feedforward gain αv are set to 1, when the control target 1 is an ideal model, the position command xr and the actual position xm are obtained. Matching control becomes possible. Further, the model error and disturbance torque τd of the controlled object 1 are compensated by the error compensation torque τc. Here, furthermore, the torque feedforward gain ατ and the speed feedforward gain αv are changed from 1 to make fine adjustments, and the slight response error of the actual position xm with respect to the position command xr due to the model error of the controlled object 1 is corrected. .
[0017]
  However, in the second prior art, if the torque feedforward gain ατ is not set to 0, a signal component obtained by second-order differentiation of the position command xr is directly applied to the torque command τr, so that the torque command τr includes a high frequency component, When the characteristics of the controlled object 1 include high-frequency mechanical resonance, there is a problem that it is difficult to realize high-speed settling by exciting the mechanical resonance.
[0018]
  In addition, since the integral of speed is a position in terms of transfer characteristics, the second prior art uses the relationship of the following expressions 7 and 8 to summarize the signals in the dimensions of torque, speed, position, and position integration. Thus, when Formula 6 is converted, the torque command calculation unit 605 calculates Formula 9 below.
  xr = (1 / s) vr (Equation 7)
  xm = (1 / s) vm (Equation 8)
  τr = ατ · τa + Kv (αv · vr−vm) + Kv (ωPI + ωx) (αx · xr−xm)
      + Kv · ωx · ωPI (1 / s) (xr−xm) (Equation 9)
  However, the above αx is expressed by the following formula 10.
  αx = (αv · ωPI + ωx) / (ωPI + ωx) (Equation 10)
[0019]
  If αx in Equation 10 is referred to as a position feedforward gain, in the second conventional technique having the structure shown in FIG. 13, the position feedforward gain αx is adjusted independently of the position gain ωx, the integral gain ωPI, and the speed feedforward gain αv. Can not do it. Here, the position gain ωx and the integral gain ωPI are a control gain that determines a response to the disturbance torque τd, that is, a feedback gain. Therefore, it is difficult to optimally set the torque feedforward gain ατ, the speed feedforward gain αv, and the position feedforward gain αx while keeping the characteristic with respect to the disturbance torque τd, that is, the feedback characteristic, optimal. There is a problem that it is difficult to optimally adjust the model error. Further, there is a problem that it is difficult to easily perform adjustment for suppressing overshoot.
[0020]
[Problems to be solved by the invention]
  As described above, in the first conventional technique, if it is attempted to suppress overshoot at the time of settling, the response of the model position xm to the position command xr needs to be considerably delayed, so the response of the actual position xm is delayed, There was a problem that it was difficult to obtain fast settling.
[0021]
  In the second prior art, a high-frequency component is applied to the torque command τr to obtain a high-speed response. Therefore, when the control target 1 has a mechanical resonance, the resonance is excited and a high-speed settling is performed. There was a problem that it was difficult to obtain. In addition, since the position feedforward gain αx cannot be set independently of the feedback gain and the velocity feedforward gain αv, a high-speed settling can be obtained with respect to a minute model error of the controlled object while maintaining an optimum response to the disturbance. There is a problem that it is difficult to realize optimal control. In addition, there is a problem that it is difficult to control at high speed by suppressing overshoot by simple calculation and simple adjustment.
[0022]
  The present invention has been made in order to solve the above-described problems. While maintaining the optimum response to disturbance, the adjustment to the minute model error of the controlled object is precisely performed, and the machine can be easily adjusted. This is to realize control that settles at high speed without exciting resonance.
[0023]
[Means for Solving the Problems]
  In the position control device according to the present invention, the control target isAs a modelAssumed input position command by calculation using inertia estimated value of control targetxrFrom model torqueτa, Model speedva, Model positionxaModel signal calculation unit that creates each signal of the model, and model torque from this model signal calculation unitτa, Model speedva, Model positionxaAnd the actual position that is the position detection signal of the control objectxmThe actual speed that is the speed detection signalvmAre input to the torque command for the control target.τrEquipped with torque command calculation unitThe position command xr from the outside, the actual position xm, and the actual speed vm are input and the torque command τr is output so that the actual position xm matches the position command xr.Torque command aboveτrIn the position control device for controlling the control object by generating a torque according to
  The model signal calculation unit receives the position command xr and calculates a model position xa calculated by a predetermined transfer function calculation, a model speed va that is a differential signal of the model position xa, and a model that is a differential signal of the model speed va. A model torque τa obtained by multiplying the acceleration by the estimated inertia value of the controlled object, and
  The torque command calculation unit is a model torque from the model signal calculation unit.τa, Model speedva, Model positionxaFor each signalBased on 1Set torque feed forward gainατ, Speed feed forward gainαvAnd position feedforward gainαxA feedforward control unit that multiplies and outputs, andAgainst disturbanceSet feedback gainPosition proportional gain Kx, velocity proportional gain Kv and position integral gain KiBased on the above actual positionxmIs the above position commandxrTo match the above torque commandτrA feedback control unit for calculating
  The torque command calculation unit inputs the model torque τa, model speed va, model position xa, actual speed vm, and actual position xm, position proportional gain Kx, speed proportional gain Kv, position integral gain Ki, and torque feed forward. The torque command τr is output based on the calculation represented by the following equation using the gain ατ, the velocity feedforward gain αv, and the position feedforward gain αx.
τr = ατ · τa + Kv · (αv · va−vm) + Kx · (αx · xa−xm) + Ki (1 / s) (xa−xm)
s: Laplace operator
  The feedforward control unitIt is possible to compensate for the error between the model and the controlled object while keeping the disturbance response by the feedback control unit optimal.Above position feed forward gainαxThe above speed feed forward gainαvAnd can be set to a value other than 1 independently of the feedback gain.
[0024]
  In the position control device according to the present invention, the control target isAs a modelAssumed input position command by calculation using the inertia estimated value of the control targetxrFrom model torqueτa, Model speedva, Model positionxaModel signal calculation unit that generates each signal of the model, and model torque from this model signal calculation unitτa, Model speedva, Model positionxaAnd the actual position that is the position detection signal of the control objectxmThe actual speed that is the speed detection signalvmAre input to the torque command for the control target.τrEquipped with torque command calculation unitThe position command xr from the outside, the actual position xm, and the actual speed vm are input and the torque command τr is output so that the actual position xm matches the position command xr.Torque command aboveτrIn the position control device for controlling the control object by generating a torque according to
  The model signal calculation unit receives the position command xr and calculates a model position xa calculated by a predetermined transfer function calculation, a model speed va that is a differential signal of the model position xa, and a model that is a differential signal of the model speed va. A model torque τa obtained by multiplying the acceleration by the estimated inertia value of the controlled object, and
  The torque command calculation unit is a model torque from the model signal calculation unit.τa, Model speedva, Model positionxaFor each signalBased on 1Set torque feed forward gainατ, Speed feed forward gainαvAnd position feedforward gainαxA feedforward control unit that multiplies and outputs, andAgainst disturbanceSet feedback gainPosition proportional gain Kx, velocity proportional gain Kv and position integral gain KiBased on the above actual positionxmIs the above position commandxrTo match the above torque commandτrA feedback control unit for calculating
  The torque command calculation unit inputs the model torque τa, model speed va, model position xa, actual speed vm, and actual position xm, position proportional gain Kx, speed proportional gain Kv, position integral gain Ki, and torque feed forward. The torque command τr is output based on the calculation represented by the following equation using the gain ατ, the velocity feedforward gain αv, and the position feedforward gain αx.
τr = ατ · τa + Kv · (αv · va−vm) + Kx · (αx · xa−xm) + Ki (1 / s) (xa−xm)
s: Laplace operator
  The feedforward control unitIt is possible to compensate for the error between the model and the controlled object while keeping the disturbance response by the feedback control unit optimal.Above position feed forward gainαxAnd speed feed forward gainαvAnd torque feed forward gainατAnd can be set to a value other than 1 independently of the feedback gain.
[0025]
  The position control device according to the present invention includes:A model signal calculation unit that creates signals of model torque τa, model speed va, and model position xa from the input position command xr by assuming the control target as a model and calculating using the inertia estimated value of the control target, and this Each signal of the model torque τa, model speed va, model position xa from the model signal calculation unit, the actual position xm that is the position detection signal of the control target, and each signal of the actual speed vm that is the speed detection signal are input, A torque command calculation unit for generating the torque command τr to be controlled is provided, and an external position command xr, the actual position xm, and the actual speed vm are input and the torque command τr is output, and the actual position xm In the position control device for controlling the control object by generating a torque according to the torque command τr so as to coincide with the position command xr,
The model signal calculation unit receives the position command xr and calculates a model position xa calculated by a predetermined transfer function calculation, a model speed va that is a differential signal of the model position xa, and a model that is a differential signal of the model speed va. A model torque τa obtained by multiplying the acceleration by the estimated inertia value of the controlled object, and
The torque command calculation unit includes a torque feed forward gain ατ, a speed feed forward gain αv, and a position feed that are set based on 1 for each of the model torque τa, model speed va, and model position xa signals from the model signal calculation unit. The actual position xm is based on the position command based on the feedforward control unit that multiplies and outputs the forward gain αx, and the position proportional gain Kx, velocity proportional gain Kv, and position integral gain Ki, which are feedback gains set for disturbance. a feedback control unit for calculating the torque command τr so as to coincide with xr;
  The torque command calculation unit inputs the model torque τa, model speed va, model position xa, actual speed vm, and actual position xm, position proportional gain Kx, speed proportional gain Kv, position integral gain Ki, and torque feed forward. The torque command τr is output based on the calculation represented by the following equation using the gain ατ, the velocity feedforward gain αv, and the position feedforward gain αx.
τr = ατ · τa + Kv · (αv · va−vm) + Kx · (αx · xa−xm) + Ki (1 / s) (xa−xm)
s: Laplace operator
  The feedforward control unitThe position feedforward gain αx, the speed feedforward gain αv, and the torque feedforward gain ατ are set independently of the feedback gain so that the disturbance response by the feedback control unit can be maintained optimally and the error between the model and the controlled object can be compensated. A configuration that uses relational expressionsIt is a thing.
[0026]
  The feedforward control unit of the position control device according to the present invention comprises:The position feedforward gain αx, the speed feedforward gain αv, and the torque feedforward gain ατ are set using the relationship of the following equation.
(Position feedforward gain αx) = (Speed feedforward gain αv)
= (Torque feed forward gain ατ)
[0027]
  The feedforward control unit of the position control device according to the present invention comprises:The position feedforward gain αx, the speed feedforward gain αv, and the torque feedforward gain ατ are set using the relationship of the following equation.
(Torque feed forward gain ατ) = (position feed forward gain αx) ³
(Velocity feedforward gain αv) = (Position feedforward gain αx) ²
[0028]
  The torque command calculation unit of the position control device according to the present invention comprises:A torque feedforward amplifier that outputs a feedforward torque τf obtained by multiplying a model torque τa by a torque feedforward gain ατ; a speed feedforward amplifier that outputs a feedforward speed vf obtained by multiplying a model speed va by a speed feedforward gain αv; A position feedforward reducer that outputs a feedforward position xf obtained by multiplying a speed va by a position feedforward reduction gain βx, and a signal obtained by integrating a signal obtained by subtracting the feedforward position xf from the deviation between the model position xa and the actual position xm. A position integrator for output, a speed proportional compensator for outputting a signal obtained by multiplying the deviation between the feedforward speed vf and the actual speed vm by a speed proportional gain Kv, and a position proportional gain for the deviation between the model position xa and the actual position xm. position proportional compensator that outputs a signal obtained by multiplying the x, and includes a position integral compensator for outputting a multiplied signal of the position integral gain Ki of the output of the position integrator,
The position feedforward gain αx is set by the following equation, and the addition value of the feedforward torque τf and the output signals of the speed proportional compensator, position proportional compensator, and position integral compensator is output as a torque command τr. .
αx = 1−Ki · βx / Kx
[0029]
  The model signal calculation unit of the position control device according to the present invention is:The transfer characteristic from the position command to the model position is configured to be a low-pass characteristic that cuts off a predetermined frequency or more.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
  FIG. 1 is a block diagram showing the configuration of the position control apparatus according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes a control object that drives a mechanical system by generating torque according to a torque command τr. Reference numeral 2 denotes a position detector that detects an actual position xm that is the position of the control object 1. A speed detector 3 detects an actual speed vm which is a differential signal of the actual position xm. Reference numeral 4 denotes a model signal calculation unit that receives a position command xr from the outside and outputs a model position xa, a model speed va, and a model torque τa. Reference numeral 5 denotes a torque command calculation unit. Reference numeral 6 denotes a position integrator. 7 is a velocity proportional compensator, 8 is a position proportional compensator, and 9 is a position integral compensator. 10 is a torque feedforward amplifier, 11 is a velocity feedforward amplifier, and 12 is a position feedforward amplifier.
[0031]
  Next, the operation of the first embodiment will be described. First, the characteristics of the controlled object 1 will be described. If the generated torque in the controlled object 1 ideally matches the torque command τr, and the transfer characteristic of the controlled object 1 is described as G (s), the relationship between the torque command τr and the disturbance torque τd and the actual position xm is as follows: It is represented by Formula 1 of However, s represents a Laplace operator in the following formula and the following.
  xm = G (s) · τr + G (s) · τd (Equation 1)
[0032]
  Further, when the control target 1 is a complete rigid machine, the transfer characteristic G (s) of the control target 1 is expressed by the following equation 2. However, in the following formula, J is the inertia of the controlled object 1,
  G (s) = 1 / (J · s²) (Formula 2)
[0033]
  However, the actual controlled object 1 has model errors such as mechanical resonance and friction. For example, the transfer characteristic G (s) of the controlled object when viscous friction with the friction coefficient f exists is expressed by the following equation (3).
  G (s) = 1 / (J · s²+ F · s) (Formula 3)
[0034]
  Next, the operation of the model signal calculation unit 4 will be described. The model signal calculation unit 4 receives a position command xr given to the position control device from the outside, calculates a model position xa based on the transfer function calculation of the model transfer characteristic Ga (s), which is a low-pass characteristic, and further calculates the model position xa. The model speed va which is a differential signal and the model acceleration aa which is a differential signal of the model speed va are calculated, and the model signal calculation unit 4 further multiplies the model acceleration aa by the model inertia Ja which is a preset inertia value of the control target. The model torque τa which is the obtained signal is calculated, and the model position xa, the model speed va, and the model torque τa are output. For the model transfer characteristic Ga (s), a second-order low-pass characteristic such as the following Expression 11 is selected.
  Ga (s) = 1 / (s + ωa)²      ... (Formula 11)
  Here, ωa in the above equation 11 is the response frequency of the model, that is, the cutoff frequency of the low-pass characteristic, and determines the speed of the response of the model to the position command xr.
[0035]
  With the above operation, the model signal calculation unit 4 performs transfer function calculations of the following formulas 12, 13, and 14.
  xa = Ga (s) · xr (12)
  va = s · Ga (s) · xr (Equation 13)
  τa = Ja · s²Ga (s) xr (Expression 14)
[0036]
  Next, the operation of the torque command calculation unit 5 will be described. The torque command calculation unit 5 inputs the model torque τa, the model speed va, the model position xa, the actual speed vm, and the actual position xm. In the torque command calculation unit 5, the torque feedforward amplifier 10 outputs a feedforward torque τf obtained by multiplying the model torque τa by the torque feedforward gain ατ, and the speed feedforward amplifier 11 outputs the speed feedforward gain αv to the model speed va. The multiplied feedforward velocity vf is output, and the position feedforward amplifier 12 outputs a feedforward position xf obtained by multiplying the model position xa by the position feedforward gain αx.
[0037]
  Next, the position integrator 6 outputs a signal obtained by integrating the deviation between the model position xa and the actual position xm, and the speed proportional compensator 7 multiplies the deviation between the feedforward speed vf and the actual speed vm by the speed proportional gain Kv. The position proportional compensator 8 outputs a signal obtained by multiplying the deviation between the feedforward position xf and the actual position xm by the position proportional gain Kx, and the position integral compensator 9 outputs the position integrator 6 to the position integrator 6 output signal. The torque command calculation unit 5 outputs a signal obtained by multiplying the integral gain Ki, and outputs a sum signal of the feedforward torque τf, the output of the speed proportional compensator 7, the output of the position proportional compensator 8, and the output of the position integral compensator 9. The controlled object 1 is controlled by outputting the torque command τr.
[0038]
  By configuring as described above, the torque command calculation unit 5 inputs the model position xa, model speed va, model torque τa, actual position xm, and actual speed vm, and calculates the torque command τr by the transfer function calculation of the following equation 15. Output.
  τr = ατ · τa + Kv (αv · va−vm) + Kx (αx · xa−xm) + Ki (1 / s) (xa−xm) (Equation 15)
[0039]
  In addition, the torque command calculation unit 5 uses the torque feedforward amplifier 10 for the torque feedforward gain ατ, the speed feedforward amplifier 11 for the speed feedforward gain αv, the position feedforward amplifier 12 for the position feedforward gain αx, and the speed proportional. Since the speed proportional gain Kv is set by the compensator 7, the position proportional gain Kx is set by the position proportional compensator 8, and the position integral gain Ki is set by the position integral compensator 9, the torque feedforward gain ατ, the speed feedforward gain αv, the position It can be set independently of the feedforward gain αx and independently of the speed proportional gain Kv, the position proportional gain Kx and the position integral gain Ki. Hereinafter, the speed proportional gain Kv, the position proportional gain Kv, and the position integral gain Ki are collectively referred to as a feedback gain, and the torque feed forward gain ατ, the speed feed forward gain αv, and the position feed forward gain αx are collectively referred to as feed. This is called forward gain.
[0040]
  In the following, the case where the controlled object 1 is an ideal rigid machine represented by the expression 1 and the model inertia Ja of the model signal calculation unit 4 and the inertia J of the controlled object 1 coincide with each other. I will call it.
[0041]
  When the feedforward gains ατ, αv, and αx are all set to 1 in FIG. 1, the equivalent conversion from the first prior art to FIG. 1 is possible. That is, the control system of FIG. 1 operates in the same manner as the first prior art, and when the control object 1 is an ideal model, the actual position xm and the model position xa completely coincide with the position command xr. However, when the control target 1 has a model error as shown in Equation 3, for example, even if the model error is small, there is a problem that the actual position xm causes a slight overshoot.
[0042]
  Next, the setting of the feedback gains Kv, Kx, Ki in the torque command calculation unit 5 will be described with reference to FIG. FIG. 2 is a diagram showing the step response of the actual position xm with respect to the disturbance τd.
[0043]
  The feedback gains Kv, Kx, Ki are set so that the fluctuation of the error between the actual position xm and the position command xr becomes as small as possible with respect to the disturbance τd. If the transfer characteristic from the disturbance τd to the actual position xm in FIG. 1 is described as Gτ (s), the outline of the step response of Gτ (s) becomes a stable waveform as shown in FIG. That is, normally, the feedback gains Kv, Kx, Ki are set so that the step response of Gτ (s) fluctuates only in the positive direction and does not go too far in the negative direction.
  Note that Gτ (s) is a response of a closed circuit including the controlled object 1, and the following equation is obtained from the transfer characteristic G (s) of the controlled object 1 and the transfer characteristic Cb (s) of the feedback control system described later. It is represented by
  Gτ (s) = G (s) / {1 + G (s) · Cb (s)}
Further, when Gτ (s) when the controlled object 1 is an ideal rigid machine of Formula 2 is described as Gτ1 (s), Gτ1 (s) is expressed by the following Formula 16.
  Gτ1 (s) = s / (J · s³+ Kv · s²+ Kx · s + Ki) (Equation 16)
[0044]
  Next, setting of the feedforward gains ατ, αv, αx will be described using a general two-degree-of-freedom control system block shown in FIG. Note that the general two-degree-of-freedom control system shown in FIG. 3 is used to analyze the response characteristics of the control system. 3, the same reference numerals as those in FIG. 1 denote the same parts. Reference numeral 13 denotes a feedback controller. Reference numeral 14 denotes a feedforward controller.
[0045]
  Next, the operation of the general two-degree-of-freedom control system shown in FIG. 3 will be described. The feedforward controller 14 receives the position command xr and outputs a feedforward torque τf by calculating a transfer function of Cf (s). The feedback controller 13 inputs the actual position xm and outputs a feedback torque τb by calculating a transfer function of Cb (s). In the two-degree-of-freedom control system of FIG. 3, the controlled object 1 is driven using the sum of the feedforward torque τf and the feedback torque τb as a torque command τr.
[0046]
  When the model signal calculation unit 4 and the torque command calculation unit 5 in FIG. 1 are equivalently converted to the general two-degree-of-freedom control system in FIG. 3, the transfer characteristic Cf (s) of the feedforward controller 14 and the transfer of the feedback controller 13. The characteristic Cb (s) is expressed by the following equations 17 and 18.
  Cf (s) = Ga (s) · Gf (s) (Equation 17)
  Cb (s) = Kv · s + Kx + Ki / s (Equation 18)
However, in the above equation 17,
  Gf (s) = (ατ · Ja · s³+ Αv ・ Kv ・ s²+ Αx · Kx · s + Ki) / s ··· (Equation 19)
It is. Further, Gf (s) when all of the feedforward gains ατ, αv, αx are set to 1 as in the following Expression 20, is set to Gf1 (s).
  Gf1 (s) = (Ja · s³+ Kv · s²+ Kx · s + Ki) / s (Equation 20
[0047]
Next, the transfer function from the feedforward torque τf to the actual position xm is exactly the same as the response Gτ (s) from the disturbance torque τd to the actual position xm. Therefore, the response from the position command xr to the actual position xm is expressed by the following equation (21).
  xm / xr = Cf (s) · Gτ (s)
            = Ga (s) · Gf (s) · Gτ (s) (Equation 21)
[0048]
  Here, in the above equation, Ga (s) is the transfer characteristic Ga (s) of the model signal calculation unit 4 as described above. By using this as the low-pass characteristic, the model signal calculation unit 4 and the controlled object 1 are controlled. This is the part that sets the speed of response. Further, the transfer characteristic Gf (s) · Gτ (s) obtained by removing the model transfer characteristic from the response from the position command xr to the actual position xm represented by Expression 21 becomes a characteristic for correcting the response, and this Gf (s) · The transfer characteristic of Gτ (s) becomes the following expression 22 from the expression 19.
  Gf (s) · Gτ (s) = (ατ · Ja · s²+ Αv · Kv · s + αx · Kx + Ki / s) · Gτ (s) (Equation 22)
[0049]
  From the above Equation 22, the response of Gf (s) · Gτ (s) is a linear sum of the responses of the disturbance response Gτ (s) shown in FIG. FIG. 4 shows Ki · Gτ (s) / s, Kx · Gτ (s), Kv · s · Gτ (s), Ja · s.²-The step response of Gτ (s) is shown respectively. Further, when the controlled object 1 is an ideal model, if the feedforward gains ατ, αv, αx are all 1, Gf (s) · Gτ (s) becomes Gf1 (s) · Gτ1 (s). 16 and Expression 20, the transfer characteristics of Gf (s) · Gτ (s) are equal to 1. That is, in this case, the sum of the four waveforms shown in FIG. Therefore, the feedforward gains ατ, αv, αx are set with 1 as a reference.
[0050]
  Here, since the control object 1 has a model error as described above, the response of Gf (s) · Gτ (s) is close to 1, but a slight error occurs. Since the response from the position command xr to the actual position xm is the above equation 21, if the response frequency ωa of the model response Ga (s) shown in equation 11 is reduced, the high frequency component of the model response itself is removed. Therefore, the error between the model position xa and the actual position xm is reduced. Therefore, for errors occurring at high frequencies such as mechanical resonance, the error between the model position xa and the actual position xm is reduced without reducing the response of the model so much by reducing the response frequency ωa of the model by a predetermined amount. be able to. However, with respect to the error generated at a relatively low frequency such as the viscous friction shown in Equation 3 and the overshoot caused by the friction, if the error is reduced by further reducing the response frequency ωa of the model, the first prior art As described above, since the response frequency ωa of the model needs to be considerably reduced, as a result, the response of the actual position xm to the position command xr is considerably delayed.
[0051]
  Therefore, for example, when the position feedforward gain αx is subtracted from 1, the response waveform of Gf (s) · Gτ (s) becomes a waveform of Kx · Gτ (s) in FIG. 1−αx) to reduce the waveform. Thus, by changing the feedforward gains αx, αv, ατ from 1, without changing the feedback gains Kv, Kx, Ki, that is, the disturbance response is kept optimal as shown in FIG. In addition, the response of the actual position xm to the position command xr can be adjusted without slowing down the response of the actual position xm to the position command xr.
[0052]
  In addition, the characteristics of the model error of the controlled object 1 are various, and in order to settle as quickly as possible corresponding to such uncertainties, position feed forward gain αx, speed feed forward gain αv, and torque feed forward gain ατ By independently adjusting, the feedback gains Kv, Kx, and Ki are fixed to optimum values, and it is possible to settle as quickly as possible by dealing finely with uncertainty.
[0053]
  Further, as shown in FIG. 2, in the normal adjustment of the feedback gains Kv, Kx, Ki, the step response of the disturbance response Gτ (s) responds only in the positive sign direction, so that the actual position with respect to the position command xr When the response of xm causes an overshoot, if αx is reduced as described above, the overshoot is always suppressed. Therefore, as an example, FIG. 5 shows a simulation using the characteristic of the controlled object 1 as an ideal model, and the Gf (s) when αx is changed small while the speed feedforward gain αv and the torque feedforward gain ατ are fixed to 1. ) · Gτ (s) response changes. If the response of the actual actual position xm causes a slight overshoot from the change in the response of Gf (s) · Gτ (s) shown in FIG. 5, only the position feedforward gain αx is made slightly smaller than 1. As a result, overshoot can be suppressed by simple calculation in the controller and simple adjustment.
[0054]
  In the above description, only the position feedforward gain αx is decreased. However, the step response of Gf (s) · Gτ (s) when only the position feedforward gain αx shown in FIG. Immediately after, it rises to 1 and then decreases once and rises slowly again to reach 1. That is, the torque command τr with respect to the position command xr contains a large amount of high frequency components that are not so much involved in overshoot suppression. On the other hand, since the characteristics in the high frequency region of the controlled object 1 often include mechanical resonance, reducing the high frequency component of the torque command τr that does not contribute to overshoot suppression has a greater effect of suppressing mechanical resonance. Become. Therefore, if the position feedforward gain αx is made smaller than 1 in order to suppress overshoot, and the speed feedforward gain αv and torque feedforward gain ατ are made smaller than 1, the vibration suppressing effect becomes larger and the settling time is shortened. Connected.
[0055]
  Here, for example, the change in the step response of Gf (s) · Gτ (s) by reducing the velocity feedforward gain αv is obtained by multiplying the waveform of Kv · s · Gτ (s) in FIG. 4 by a constant. The change in the step response of Gf (s) · Gτ (s) due to the decrease in torque feedforward gain ατ is represented by Ja · s in FIG.²-Since the product of Gτ (s) multiplied by a constant is subtracted, the response waveform changes in both positive and negative directions. If the speed feedforward gain αv and torque feedforward gain ατ are inadvertently reduced, On the contrary, it causes overshooting, and a specific frequency component remains, so that the response becomes oscillating. Therefore, by providing the feedforward gains αx, αv, and ατ with appropriate relational expressions, it is possible to suppress overshoot with a simple adjustment and obtain a vibration suppressing effect.
[0056]
  Next, as an example, a case where the feedforward gains αx, αv, ατ have the relationship of the following Expression 23 will be described.
    αx = αv = ατ (Equation 23)
[0057]
  The response of Gf (s) · Gτ (s) when the feedforward gains αx, αv, ατ are reduced from 1 with the relationship of the above equation 23 is expressed by the following equation 24 from the equation 23.
  Gf (s) · Gτ (s) = αx · Gf1 (s) · Gτ (s) + Ki · (1−αx) · Gτ (s) / s (Equation 24)
  That is, since the transfer characteristics of Gf1 (s) · Gτ (s) are close to 1, the step response waveform of Gf (s) · Gτ (s) has a step-like change in height αx and Ki shown in FIG.・ The sum is obtained by multiplying the waveform of Gτ (s) / s by a constant. FIG. 6 shows the steps of Gf (s) · Gτ (s) when the transfer characteristic of Gf1 (s) · Gτ (s) is set to 1 and the feedforward gain αx is made smaller while maintaining the relationship of Equation 23. Indicates a change in response. When Gf1 (s) · Gτ (s) causes a slight overshoot from the state of change in the figure, it is smoother if the feedforward gains αx, αv, and ατ are reduced after the relationship of Equation 23 is satisfied. In addition, overshoot can be suppressed by a simple adjustment with one parameter αx.
[0058]
  Next, as an example, a case will be described in which the feed forward gains αx, αv, ατ have the relationship of the following Expression 25.
    αv = αx², Ατ = αx³    .... (Formula 25)
[0059]
  Gf (s) when the feed forward gains αx, αv, ατ are reduced from 1 by giving the relationship of the above equation 25 is expressed by the following equation.
    Gf (s) = {Ja · (αx · s)³+ Kv · (αx · s)²+ Kx · αx · s + Ki) / s
FIG. 7 shows the steps of Gf (s) · Gτ (s) when the transfer characteristic of Gf1 (s) · Gτ (s) is set to 1 and the feedforward gain αx is reduced while the relationship of Expression 25 is satisfied. Indicates a change in response. When Gf1 (s) · Gτ (s) causes a slight overshoot from the state of the change in the figure, if the feedforward gains αx, αv, ατ are reduced while maintaining the relationship of Equation 25, the rise It is possible to suppress overshoot smoothly and with a simple adjustment with one parameter αx while reducing the high frequency component, that is, making the high frequency component smaller.
[0060]
  The first embodiment includes the position feedforward amplifier 12 that is a feedforward gain setting element by configuring as described above, and the position feedforward gain αx is independent of the speed feedforward gain αv, and is the speed proportional gain Kv, position Since the proportional gain Kx and the position integral gain Ki can be set to values other than 1, the position feedforward gain αx in the position feedforward amplifier 12 can be set to 1 even if the torque feedforward gain ατ and the speed feedforward gain αv remain at 1. By making small fine adjustments with reference to the above, it is possible to perform settling at a high speed by suppressing the overshoot while keeping the disturbance response optimal with a simple controller operation.
[0061]
  Further, the first embodiment includes a torque feedforward amplifier 10, a speed feedforward amplifier 11, and a position feedforward amplifier 12 that are feedforward setting elements. The feedforward gains ατ, αv, and αx are independent of each other and the feedback gain Kv. , Kx, Ki can be set to a value other than 1 so that the feedforward gain ατ, αv, αx can be finely adjusted with 1 as a reference, and the disturbance response can be kept at an optimum level, allowing fast settling. Is possible.
[0062]
  Further, the first embodiment includes a torque feedforward amplifier 10, a speed feedforward amplifier 11, and a position feedforward amplifier 12 that are feedforward setting elements, and feedforward gains ατ, αv, αx are set as feedback gains Kv, Kx, Ki. By setting one parameter using an independent and appropriate relational expression, fine adjustment of the feedforward gain ατ, αv, αx with one parameter αx with reference to 1 keeps the disturbance response optimal. It is possible to set the surface smoothly and smoothly while suppressing overshoot.
[0063]
  Further, the first embodiment is configured such that the response from the position command xr to the model position xa in the model signal calculation unit 4 has a low-pass characteristic, and includes a position feedforward amplifier 12 that is a feedforward setting element, and a position feedforward gain. Since αx can be set to a value other than 1, the model transfer characteristic Ga (s) is set as a low-pass characteristic, excitation of mechanical resonance is suppressed, and the position feedforward gain αx is finely adjusted with reference to 1 to make a disturbance response. It is possible to stabilize at high speed while suppressing vibration and suppressing overshoot while maintaining the optimum value.
[0064]
  In the above description of the first embodiment, the torque command calculation unit 5 is configured to include a torque feedforward amplifier. However, the model inertia Ja is controlled by the transfer function calculation of Expression 14 in the model signal calculation unit 4. Needless to say, the same effect can be obtained even if the inertia J is multiplied by the torque feed forward gain ατ.
[0065]
  Further, for example, even when a low-pass filter is inserted in the signal such as the output of the speed proportional compensator 8, the essential effect of the present invention is not changed, and it goes without saying that the same effect is obtained.
  Furthermore, suppression of high-frequency mechanical resonance may be performed by adjusting the settings of the feedforward gains described above, instead of using a low-pass characteristic for the transfer function of the model signal calculation unit 4 depending on the conditions. Needless to say, you can.
[0066]
Embodiment 2. FIG.
  FIG. 8 is a block diagram showing the configuration of the position control apparatus according to the second embodiment. 8, the same reference numerals as those in FIG. 1 denote the same parts, and the description thereof is omitted.
[0067]
  Reference numeral 105 denotes a torque command calculation unit. Reference numeral 106 denotes a position integrator. 107 is a velocity proportional compensator, 108 is a position proportional compensator, and 109 is a position integral compensator. 110 is a torque feedforward amplifier, 111 is a speed feedforward amplifier, and 112 is a position feedforward reducer.
[0068]
  In the first embodiment shown in FIG. 1, the torque command τr is calculated using the difference signal between the feedforward position xf obtained by multiplying the model position xa by the position feedforward gain αx and the actual position. When the moving distance is large, the output of the position proportional compensator 8 is constantly increased, and the output signal of the position integral compensator 9 has a large value so as to cancel out this output, so that the calculation condition becomes worse. Although there is a possibility, the second embodiment eliminates the above problems.
[0069]
  Next, the operation of the second embodiment will be described. The operation of the torque command calculation unit 105, which is a part different from the first embodiment, will be described. The torque command calculation unit 105 inputs the model torque τa, the model speed va, the model position xa, the actual speed vm, and the actual position xm. In the torque command calculation unit 105, the torque feedforward amplifier 110 outputs a feedforward torque τf obtained by multiplying the model torque τa by the torque feedforward gain ατ, and the speed feedforward amplifier 111 outputs the speed feedforward gain αv to the model speed va. The multiplied feedforward speed vf is output, and the position feedforward reducer 112 outputs a feedforward position (position feedforward reduction signal) xf obtained by multiplying the model speed va by the position feedforward reduction gain βx.
[0070]
  Next, the position integrator 106 outputs a signal obtained by integrating the signal obtained by subtracting the position feedforward reduction signal xf from the deviation between the model position xa and the actual position xm, and the speed proportional compensator 107 calculates the feedforward speed vf and the actual position xm. The position proportional compensator 108 outputs a signal obtained by multiplying the deviation between the model position xa and the actual position xm by the position proportional gain Kx, and outputs a signal obtained by multiplying the deviation from the speed vm by the speed proportional gain Kv. The unit 109 outputs a signal obtained by multiplying the output signal of the position integrator 106 by the position integration gain Ki, and the torque command calculation unit 105 outputs the feedforward torque τf, the output of the speed proportional compensator 107 and the output of the position proportional compensator 108. The controlled object 1 is controlled by outputting the sum signal of the output from the position integral compensator 109 as the torque command τr.
[0071]
  By configuring as described above, the torque command calculation unit 105 outputs the torque command τr by the transfer function calculation of the following equation 26 based on the model position xa, model speed va, model torque τa, actual position xm, and actual speed vm. To do.
  τr = ατ · τa + Kv (αv · va−vm) + Kx (xa−xm) + Ki (1 / s) (xa−xm−βx · va) (Equation 26)
[0072]
  Here, since the integration of the model speed va is the model position xa, when Expression 26 is converted so that the signal is summarized in the dimension of integration of torque, speed, position, and position, Expression 27 is obtained.
  τr = ατ · τa + Kv (αv · va−vm) + Kx {(1−Ki · βx / Kx) xa−xm} + Ki (1 / s) (xa−xm) (Equation 27)
[0073]
  Therefore, when the position feedforward gain αx is defined by the following equation 28, the calculation of the above equation 26 is exactly the same as the calculation of equation 15 in the torque command calculation unit 5 of the first embodiment.
  αx = 1−Ki · βx / Kx (Equation 28)
[0074]
  τr = ατ · τa + Kv (αv · va−vm) + Kx (αx · xa−xm) + Ki (1 / s) (xa−xm) (Equation 15)
[0075]
  Further, by setting the position feedforward reduction gain βx, the position feedforward gain αx can be set independently of the speed feedforward gain αv and the feedback gains Kv, Kx, Ki.
[0076]
  By configuring as described above, the second embodiment has exactly the same effect as the first embodiment, and the output of the position proportional compensator 108 is particularly large even if the position command xr is large. And stable operating characteristics can be obtained.
[0077]
Embodiment 3 FIG.
  FIG. 9 is a block diagram showing a control system of the third embodiment. 9, the same reference numerals as those in FIG. 1 denote the same parts, and a description thereof will be omitted.
[0078]
  Reference numeral 205 denotes a torque command calculation unit. Reference numeral 206 denotes a position compensator, and 207 denotes a speed PI compensator. 210 is a torque feedforward amplifier, and 211 is a speed feedforward amplifier.
[0079]
  Next, the operation of the third embodiment will be described. The operation of the torque command calculation unit 205, which is a different part from the first embodiment, will be described. The torque command calculation unit 205 inputs the model torque τa, the model speed va, the model position xa, the actual speed vm, and the actual position xm. In the torque command calculation unit 205, the torque feedforward amplifier 210 outputs a feedforward torque τf obtained by multiplying the model torque τa by the torque feedforward gain ατ, and the speed feedforward amplifier 211 outputs the speed feedforward gain αv to the model speed va. The multiplied feed forward speed vf is output.
[0080]
  Next, the position compensator 206 outputs a signal obtained by multiplying the deviation between the model position xa and the actual position xm by the position gain ωx, and the speed PI compensator 207 performs position compensation on the difference signal between the feedforward speed vf and the actual speed vm. A signal obtained by adding the output of the converter 106 is input, PI (proportional integration) calculation of the speed proportional gain Kv and the integral gain ωPI is performed, and the error compensation torque τc is output. Further, the torque command calculation unit 205 outputs a sum signal of the feedforward torque τf and the error compensation torque τc as the torque command τr. That is, the torque command calculation unit 205 calculates the torque command τr by the following equation 29.
  τr = ατ · τa + Kv (1 + ωPI / s) {αv · va−vm + ωx (xa−xm)} (Equation 29)
[0081]
  Here, since the integration of the model velocity va is the model position xa, when the equation 29 is transformed so that the signal is summarized in the dimensions of the torque, velocity, position, and position integration, the following equation 30, equation 31, equation 32, Equation 33 is obtained.
  τr = ατ · τa + Kv (αv · va−vm) + Kx (αx · xa−xm) + Ki (1 / s) (xa−xm) (Equation 30)
  However,
  Kx = Kv (ωx + ωPI) (Equation 31)
  Ki = Kv · ωx · ωPI (Equation 32)
  αx = (ωx + αv · ωPI) / (ωx + ωPI) (Expression 33)
[0082]
  From the above equations 31, 32, and 33, the position feedforward gain αx in equation 30 cannot be set independently of the velocity feedforward gain αv and independently of the position proportional gain Kx and the position integral gain Ki. However, by making the speed feedforward gain αv in the speed feedforward amplifier 211 smaller than 1, the position feedforward gain αx in Expression 15 also becomes smaller than 1. Further, since the relationship between the position feedforward gain αx and the speed Ford forward gain αv is determined by the relationship between the position gain ωx as the feedback gain and the integral gain ωPI according to Expression 33, the feedback characteristics slightly change, but this position gain ωx And the integral gain ωPI are adjusted so that the position feedforward gain αx is rapidly reduced by decreasing the speed Ford forward gain αv, and the overshoot can be suppressed by adjusting the speed Ford forward gain αv. You can be sure.
[0083]
  For mechanical resonance of high frequency, as in the first embodiment, by reducing the response frequency ωa of the model transfer characteristic Ga (s) in the model signal calculation unit 4, a large mechanical vibration suppression effect can be obtained. It is done.
[0084]
  By configuring as described above, the third embodiment includes the model signal calculation unit 4 in which the transfer characteristic from the position command xr to the model position xa has a low-pass characteristic, and the speed feedforward amplifier 211 that is a feedforward gain setting element. Thus, by reducing the position feedforward gain αx, the effect of suppressing disturbance is somewhat sacrificed, but it is possible to suppress vibrations with a relatively simple calculation and to settle at high speed by suppressing overshoot.
[0085]
Embodiment 4 FIG.
  FIG. 10 is a block diagram showing a control system of the fourth embodiment. 10, the same reference numerals as those in FIG. 1 denote the same parts, and a description thereof will be omitted.
[0086]
  A model signal calculation unit 304 receives a position command xr from the outside and outputs a model position xa, a model speed va, and a model torque τa. Reference numeral 313 denotes a first differentiator. 314 is a second differentiator. Reference numeral 315 denotes an inertial amplifier. Reference numeral 305 denotes a torque command calculation unit. Reference numeral 306 denotes a position compensator, and reference numeral 307 denotes a speed PI compensator. 310 is a torque feedforward amplifier, 311 is a speed feedforward reducer, and 312 is a position feedforward reducer.
[0087]
  Next, the operation of the fourth embodiment will be described. The model signal calculation unit 304 receives the position command xr, the first differentiator 313 differentiates the position command xr and outputs the speed command vr, and the second differentiator 314 differentiates the speed command vr and the acceleration command. ar is output, and the inertia amplifier 315 outputs a model torque τa obtained by multiplying the acceleration command ar by the preset estimated value Ja of the inertia of the control target 1.
[0088]
  With the above operation, the model signal calculation unit 304 performs transfer function calculations of the following formulas 34, 35, and 36.
  xa = xr (formula 34)
  va = s · xr (formula 35)
  τa = Ja · s²Xr (Formula 36)
[0089]
  From the above equations 34, 35, and 36, the model signal calculation unit 304 in the fourth embodiment is different from the model signal calculation unit 4 in the first embodiment in which the model transfer characteristic Ga (s) is set to 1. Don't be. Therefore, the model transfer characteristic Ga (s) does not have a low-pass characteristic, but has the same characteristics as those in the first embodiment except for the above.
[0090]
  Next, the operation of the torque command calculation unit 305 will be described. The torque command calculation unit 305 inputs the model torque τa, the model speed va, the model position xa, the actual speed vm, and the actual position xm. In the torque command calculation unit 305, the torque feedforward amplifier 310 outputs a feedforward torque τf obtained by multiplying the model torque τa by the torque feedforward gain ατ, and the speed feedforward reducer 311 outputs the speed feedforward reduction gain to the model speed va. A feedforward speed (velocity feedforward reduction signal) vf multiplied by γv is output, and the position feedforward reducer 312 multiplies the model position xa by a position feedforward reduction gain γx (position feedforward reduction signal) xf. Is output.
[0091]
  Next, the position compensator 306 outputs a signal obtained by multiplying the deviation between the model position xa and the actual position xm by the position gain ωx, and the speed PI compensator 307 detects the deviation between the model speed va and the actual speed vm. Is input, and a PI (proportional integration) calculation of the speed proportional gain Kv and the integral gain ωPI is performed to output the error compensation torque τc. The torque command calculation unit 305 outputs a signal obtained by adding the error compensation torque τc to the signal obtained by subtracting the speed feedforward reduction signal vf and the position feedforward reduction signal xf from the feedforward torque τf as the torque command τr. That is, the torque command calculation unit 305 calculates the torque command τr by the calculation of Expression 37 below.
  .tau.r = .alpha..tau.a-.gamma.v.va-.gamma.x.xa + Kv. (1 + .omega.PI / s) {va-vm + .omega.x (xa-xm)} (Equation 37)
[0092]
  Here, since the integration of the model speed va is the model position xa and the integration of the actual speed vm is the actual position xm, if Equation 37 is converted so that the signals are integrated in the dimensions of torque, speed, position, and position integration, Equation 38, Equation 39, Equation 40, and Equation 41 are obtained.
  τr = ατ · τa + Kv (αv · va−vm) + Kx (αx · xa−xm) + Ki (1 / s) (xa−xm) (Equation 38)
  However,
  Kx = Kv (ωx + ωPI) (Equation 39)
  Ki = Kv · ωx · ωPI (Equation 40)
  αv = 1−γv / Kv (Formula 41)
  αx = 1−γx / Kx (Equation 42)
[0093]
  Therefore, the speed feedforward gain αv can be set independently by setting the speed feedforward reduction gain γv by the speed feedforward reducer 311, and the position can be set by setting the position feedforward reduction gain γx by the position feedforward reducer 312. The feedforward gain αx can be set independently.
[0094]
  The fourth embodiment includes the position feedforward reducer 312 that is a feedforward gain setting element even when the feedback control system is configured with a position compensator and a speed PI compensator by configuring as described above. Since the position feedforward gain αx can be set to a value other than 1 independently of the speed feedforward gain αv and independently of the feedback gain, the position feedforward gain can be set even if the torque feedforward gain ατ and the speed feedforward gain αv remain at 1. By finely adjusting αx with 1 as a reference, it is possible to set up at a high speed by suppressing the overshoot while keeping the disturbance response optimal with a simple controller calculation.
[0095]
  Further, the fourth embodiment includes a torque feedforward amplifier 310, a speed feedforward reducer 311 and a position feedforward reducer 312 which are feedforward setting elements, and feedforward gains ατ, αv and αx are mutually independent and fed back. Since it can be set to a value other than 1 independently of the gain, it is possible to set the feedforward gain ατ, αv, αx finely with 1 as a reference, allowing fast settling while keeping the disturbance response optimal. is there.
[0096]
Embodiment 5 FIG.
  FIG. 11 is a block diagram showing a control system configuration of the fifth embodiment. In FIG. 11, the same reference numerals as those in FIG.
[0097]
  Reference numeral 405 denotes a torque command calculation unit. Reference numeral 406 denotes an integrator. 407 is a velocity proportional compensator, 408 is a position proportional compensator, and 409 is a position integral compensator. 410 is a torque feedforward amplifier, and 411 is a speed feedforward amplifier.
[0098]
  Next, the operation of the fifth embodiment will be described. The operation of the torque command calculation unit 405, which is a part different from the first embodiment, will be described. The torque command calculation unit 405 inputs the model torque τa, the model speed va, the model position xa, the actual speed vm, and the actual position xm. Inside the torque command calculation unit 405, the torque feedforward amplifier 410 outputs a feedforward torque τf obtained by multiplying the model torque τa by the torque feedforward gain ατ, and the speed feedforward amplifier 411 adds the speed feedforward gain αv to the model speed va. The multiplied feed forward speed vf is output.
[0099]
  Next, the position integral compensator 409 outputs a signal obtained by multiplying the deviation between the model position xa and the actual position xm by the position integral gain ωi, and the integrator 406 receives the model speed va and the feedforward speed from the output of the position integral compensator 409. A signal obtained by subtracting the difference signal from vf is input and an integrated signal is output. Next, the position proportional compensator 408 inputs a signal obtained by adding the output of the integrator 406 to the difference signal between the model position xa and the actual position xm, and outputs a signal obtained by multiplying the position gain ωx. Next, the speed proportional compensator 407 inputs a signal obtained by adding the output of the position proportional compensator 408 to the difference signal between the feedforward speed vf and the actual speed vm, and outputs a signal obtained by multiplying the speed proportional gain Kv by the torque command calculation. The unit 405 outputs a sum signal of the output of the speed proportional compensator 407 and the feedforward torque τf as a torque command τr. That is, the torque command calculation unit 405 calculates the torque command τr by the following equation 43.
  τr = ατ · τa + Kv [αv · va−vm + ωx {xa−xm + (1 / s) (ωi (xa−xm) − (1−αv) va)}] (Expression 43)
[0100]
  Here, since the integration of the model speed va is the model position xa, if the equation 43 is transformed so that the signal is summarized in the dimensions of the torque, velocity, position, and position integration, the following equations 44, 45, 46, Equation 47 is obtained.
  τr = ατ · τa + Kv (αv · va−vm) + Kx (αx · xa−xm) + Ki (1 / s) (xa−xm) (formula 44)
  However,
  Kx = ωx · Kv (Equation 45)
  Ki = ωi · ωx · Kv (formula 46)
  αx = αv (formula 47)
[0101]
  From the above Expression 45, Expression 46, and Expression 47, the position feedforward gain αx in Expression 15 is the same value as the velocity feedforward gain αv. Further, by setting the torque feedforward gain ατ by the torque feedforward amplifier 410 which is a feedforward gain setting element and the speed feedforward gain αv of the speed feedforward amplifier 411, the speed feedforward gain αv and the position feedforward gain αx are set. Can be set independently of the feedback gain. Furthermore, when a relational expression is set such that the torque feedforward gain ατ in FIG. 11 is the same value as the speed feedforward gain αv, the expression in the first embodiment is between the feedforward gains ατ, αv, and αx in Expression 44. Since the relationship 23 is established, it is possible to adjust so as to smoothly suppress overshoot with one parameter αv as in the first embodiment.
[0102]
  The fifth embodiment is configured as described above to include the torque feedforward amplifier 410 and the speed feedforward amplifier 411 that are feedforward setting elements, and with relatively simple calculation, the position feedforward gain αx and the speed Ford forward can be obtained. All of the feedforward gains ατ, αv, αx can be set to values other than 1 independently of the feedback gain while maintaining a good relationship with the gain αv, so that overshoot is suppressed and the disturbance response is kept optimal. It is possible to settle at high speed.
[0103]
  Further, the fifth embodiment includes a torque feedforward amplifier 410 and a speed feedforward amplifier 411 which are feedforward setting elements. The feedforward gains ατ, αv, and αx are independent of the feedback gains and are expressed by using an appropriate relational expression. By setting with parameters, the feedforward gain ατ, αv, αx is finely adjusted with one parameter αv with 1 as a reference, and overshoot is suppressed while maintaining the disturbance response optimally, and the settling is smooth and fast. It is possible to make it.
[0104]
  The present invention is not limited to the specific circuit configuration examples described in the above embodiments, and a torque command calculation unit having the predetermined model signal calculation unit, feedback control unit, and feedforward control unit described above. Various circuits that enable position feedforward gain to be set independently of velocity feedforward gain, independent of feedback gain, and all position, velocity, and torque feedforward gains can be set independently of feedback gain. Needless to say, the present invention can be applied to the configuration example.
[0105]
【The invention's effect】
  As described above, the position control device according to the present invention controls the control object.As a modelAssumed input position command by calculation using inertia estimated value of control targetxrFrom model torqueτa, Model speedva, Model positionxaModel signal calculation unit that generates each signal of the model, and model torque from this model signal calculation unitτa, Model speedva, Model positionxaAnd the actual position that is the position detection signal of the control objectxmThe actual speed that is the speed detection signalvmAre input to the torque command for the control target.τrEquipped with torque command calculation unitThe position command xr from the outside, the actual position xm, and the actual speed vm are input and the torque command τr is output so that the actual position xm matches the position command xr.Torque command aboveτrIn the position control device for controlling the control object by generating a torque according to
  The model signal calculation unit receives the position command xr and calculates a model position xa calculated by a predetermined transfer function calculation, a model speed va that is a differential signal of the model position xa, and a model that is a differential signal of the model speed va. A model torque τa obtained by multiplying the acceleration by the estimated inertia value of the controlled object, and
  The torque command calculation unit is a model torque from the model signal calculation unit.τa, Model speedva, Model positionxaFor each signalBased on 1Set torque feed forward gainατ, Speed feed forward gainαvAnd position feedforward gainαxA feedforward control unit that multiplies and outputs, andAgainst disturbanceSet feedback gainPosition proportional gain Kx, velocity proportional gain Kv and position integral gain KiBased on the above actual positionxmIs the above position commandxrTo match the above torque commandτrA feedback control unit for calculating
  The torque command calculation unit inputs the model torque τa, model speed va, model position xa, actual speed vm, and actual position xm, position proportional gain Kx, speed proportional gain Kv, position integral gain Ki, and torque feed forward. The torque command τr is output based on the calculation represented by the following equation using the gain ατ, the velocity feedforward gain αv, and the position feedforward gain αx.
τr = ατ · τa + Kv · (αv · va−vm) + Kx · (αx · xa−xm) + Ki (1 / s) (xa−xm)
s: Laplace operator
  The feedforward control unitIt is possible to compensate for the error between the model and the controlled object while keeping the disturbance response by the feedback control unit optimal.Above position feed forward gainαxThe above speed feed forward gainαvSince it is configured to be set to a value other than 1 independently of the feedback gain,A simple fine adjustment of changing the position feedforward gain with reference to 1 makes it possible to suppress overshoot while maintaining the optimum characteristics against disturbance determined by each feedback gain Kx, Kv, Ki, and to control at high speed. Can be realized.
[0106]
  In addition, the position control device according to the present invention controls the control object.As a modelAssumed input position command by calculation using inertia estimated value of control targetxrFrom model torqueτa, Model speedva, Model positionxaModel signal calculation unit that generates each signal of the model, and model torque from this model signal calculation unitτa, Model speedva, Model positionxaAnd the actual position that is the position detection signal of the control objectxmThe actual speed that is the speed detection signalvmAre input to the torque command for the control target.τrEquipped with torque command calculation unitThe position command xr from the outside, the actual position xm, and the actual speed vm are input and the torque command τr is output so that the actual position xm matches the position command xr.Torque command aboveτrIn the position control device for controlling the control object by generating a torque according to
  The model signal calculation unit receives the position command xr and calculates a model position xa calculated by a predetermined transfer function calculation, a model speed va that is a differential signal of the model position xa, and a model that is a differential signal of the model speed va. A model torque τa obtained by multiplying the acceleration by the estimated inertia value of the controlled object, and
  The torque command calculation unit is a model torque from the model signal calculation unit.τa, Model speedva, Model positionxaFor each signalBased on 1Set torque feed forward gainατ, Speed feed forward gainαvAnd position feedforward gainαxA feedforward control unit that multiplies and outputs, andAgainst disturbanceSet feedback gainPosition proportional gain Kx, velocity proportional gain Kv and position integral gain KiBased on the above actual positionxmIs the above position commandxrTo match the above torque commandτrA feedback control unit for calculating
  The torque command calculation unit inputs the model torque τa, model speed va, model position xa, actual speed vm, and actual position xm, position proportional gain Kx, speed proportional gain Kv, position integral gain Ki, and torque feed forward. The torque command τr is output based on the calculation represented by the following equation using the gain ατ, the velocity feedforward gain αv, and the position feedforward gain αx.
τr = ατ · τa + Kv · (αv · va−vm) + Kx · (αx · xa−xm) + Ki (1 / s) (xa−xm)
s: Laplace operator
  The feedforward control unitIt is possible to compensate for the error between the model and the controlled object while keeping the disturbance response by the feedback control unit optimal.Above position feed forward gainαxAnd speed feed forward gainαvAnd torque feed forward gainατSince all of the above can be set to a value other than 1 independently of the feedback gain,By a simple fine adjustment of changing the position feedforward gain, speed feedforward gain, and torque feedforward gain with reference to 1, it is possible to keep the characteristics against disturbance determined by each feedback gain Kx, Kv, Ki while maintaining the optimum characteristics. Control of the chute can be suppressed and settable at high speed.
[0107]
  Moreover, the position control device according to the present invention isA model signal calculation unit that creates signals of model torque τa, model speed va, and model position xa from the input position command xr by assuming the control target as a model and calculating using the inertia estimated value of the control target, and this Each signal of the model torque τa, model speed va, model position xa from the model signal calculation unit, the actual position xm that is the position detection signal of the control target, and each signal of the actual speed vm that is the speed detection signal are input, A torque command calculation unit for generating the torque command τr to be controlled is provided, and an external position command xr, the actual position xm, and the actual speed vm are input and the torque command τr is output, and the actual position xm In the position control device for controlling the control object by generating a torque according to the torque command τr so as to coincide with the position command xr,
The model signal calculation unit receives the position command xr and calculates a model position xa calculated by a predetermined transfer function calculation, a model speed va that is a differential signal of the model position xa, and a model that is a differential signal of the model speed va. A model torque τa obtained by multiplying the acceleration by the estimated inertia value of the controlled object, and
The torque command calculation unit includes a torque feed forward gain ατ, a speed feed forward gain αv, and a position feed that are set based on 1 for each of the model torque τa, model speed va, and model position xa signals from the model signal calculation unit. The actual position xm is based on the position command based on the feedforward control unit that multiplies and outputs the forward gain αx, and the position proportional gain Kx, velocity proportional gain Kv, and position integral gain Ki, which are feedback gains set for disturbance. a feedback control unit for calculating the torque command τr so as to coincide with xr;
  The torque command calculation unit inputs the model torque τa, model speed va, model position xa, actual speed vm, and actual position xm, position proportional gain Kx, speed proportional gain Kv, position integral gain Ki, and torque feed forward. The torque command τr is output based on the calculation represented by the following equation using the gain ατ, the velocity feedforward gain αv, and the position feedforward gain αx.
τr = ατ · τa + Kv · (αv · va−vm) + Kx · (αx · xa−xm) + Ki (1 / s) (xa−xm)
s: Laplace operator
  The feedforward control unitThe position feedforward gain αx, the speed feedforward gain αv, and the torque feedforward gain ατ are set independently of the feedback gain so that the disturbance response by the feedback control unit can be maintained optimally and the error between the model and the controlled object can be compensated. Configuration set using relational expressionsSoOvershoot can be suppressed by simpler fine adjustment while maintaining the optimum characteristics for disturbance determined by the feedback gains Kx, Kv, and Ki, and control capable of settling at high speed can be realized.
[0108]
  The feedforward control unit of the position control device according to the present invention isSince the position feedforward gain αx, the speed feedforward gain αv, and the torque feedforward gain ατ are set using the relationship of the following equations, the characteristics with respect to the disturbance determined by each feedback gain Kx, Kv, Ki are optimized. While maintaining, overshoot can be suppressed smoothly by simple fine adjustment with one parameter, and control capable of settling at high speed can be realized.
(Position feedforward gain αx) = (Speed feedforward gain αv)
= (Torque feed forward gain ατ)
[0109]
  The feedforward control unit of the position control device according to the present invention isSince the position feedforward gain αx, the speed feedforward gain αv, and the torque feedforward gain ατ are set using the relationship of the following equations, the characteristics with respect to the disturbance determined by each feedback gain Kx, Kv, Ki are optimized. While maintaining, overshoot can be suppressed smoothly by simple fine adjustment with one parameter, and control capable of settling at high speed can be realized.
(Torque feed forward gain ατ) = (position feed forward gain αx) ³
(Velocity feedforward gain αv) = (Position feedforward gain αx) ²
[0110]
  In addition, the torque command calculation unit of the position control device according to the present invention includes:A torque feedforward amplifier that outputs a feedforward torque τf obtained by multiplying a model torque τa by a torque feedforward gain ατ; a speed feedforward amplifier that outputs a feedforward speed vf obtained by multiplying a model speed va by a speed feedforward gain αv; A position feedforward reducer that outputs a feedforward position xf obtained by multiplying a speed va by a position feedforward reduction gain βx, and a signal obtained by integrating a signal obtained by subtracting the feedforward position xf from the deviation between the model position xa and the actual position xm. A position integrator for output, a speed proportional compensator for outputting a signal obtained by multiplying the deviation between the feedforward speed vf and the actual speed vm by a speed proportional gain Kv, and a position proportional gain for the deviation between the model position xa and the actual position xm. position proportional compensator that outputs a signal obtained by multiplying the x, and includes a position integral compensator for outputting a multiplied signal of the position integral gain Ki of the output of the position integrator,
The position feedforward gain αx is set by the following equation, and the addition value of the feedforward torque τf and the output signal of the speed proportional compensator, position proportional compensator, and position integral compensator is output as a torque command τr. Even when the command xr is large, a stable control operation is performed.
αx = 1−Ki · βx / Kx
[0111]
  Further, the model signal calculation unit of the position control device according to the present invention is:Since the transmission characteristic from the position command to the model position is a low-pass characteristic that cuts a predetermined frequency or more, the torque feedforward gain ατ, the speed Ford forward gain αv, and the position feedforward gain αx are set to 1. Thus, it is possible to realize control capable of settling at high speed while suppressing excitation of mechanical resonance while maintaining optimum characteristics against disturbance.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a position control device according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a response waveform with respect to a disturbance in a normal control system.
FIG. 3 is a block diagram of a general two-degree-of-freedom control system.
FIG. 4 is a diagram showing response characteristics of signals according to the present invention.
FIG. 5 is a diagram showing an example of a response change in the first embodiment of the present invention.
FIG. 6 is a diagram showing an example of a response change in the first embodiment of the present invention.
FIG. 7 is a diagram showing an example of a response change in the first embodiment of the present invention.
FIG. 8 is a configuration diagram of a position control device according to a second embodiment of the present invention.
FIG. 9 is a configuration diagram of a position control device according to a third embodiment of the present invention.
FIG. 10 is a configuration diagram of a position control device according to a fourth embodiment of the present invention.
FIG. 11 is a configuration diagram of a position control device according to a fifth embodiment of the present invention.
FIG. 12 is a configuration diagram of a first conventional position control device.
FIG. 13 is a configuration diagram of a second conventional position control device.
[Explanation of symbols]
  1 Control object, 2 Position detector, 3 Speed detector, 4,304 Model signal calculation unit,
5, 105, 205, 305, 405 Torque command calculation unit, 6, 106 position integrator,
7,107 Speed proportional compensator, 8,108 Position proportional compensator,
9,109 position integral compensator,
10, 110, 210, 310, 410 torque feedforward amplifier,
11, 111, 211, 411 speed feedforward amplifier,
12 position feedforward amplifier, 112 position feedforward reducer,
206,306 Position compensator, 207,307 Speed PI compensator,
311 speed feedforward reducer, 312 position feedforward reducer,
406 integrator, 407 velocity proportional compensator, 408 position proportional compensator,
409 Position integral compensator, xr position command, xm actual position, vm actual speed,
τa model torque, va model speed, xa model position,
ατ Torque feed forward gain, αv Speed feed forward gain,
αx position feedforward gain, τf feedforward torque,
vf feedforward speed, xf feedforward position,
βx position feedforward reduction gain, γv velocity feedforward reduction gain, γx position feedforward reduction gain.

Claims (7)

A model signal calculation unit that generates signals of model torque τa , model speed va , and model position xa from the input position command xr by assuming the control target as a model and using the inertia estimated value of the control target, and this The model torque τa , model speed va , model position xa signals from the model signal calculation unit, the actual position xm that is the position detection signal of the controlled object, and the actual speed vm signal that is the speed detection signal are input, A torque command calculation unit for generating the torque command τr to be controlled is provided , and an external position command xr, the actual position xm, and the actual speed vm are input and the torque command τr is output, and the actual position xm In the position control device for controlling the control object by generating a torque according to the torque command τr so as to coincide with the position command xr ,
The model signal calculation unit receives the position command xr and calculates a model position xa calculated by a predetermined transfer function calculation, a model speed va that is a differential signal of the model position xa, and a model that is a differential signal of the model speed va. A model torque τa obtained by multiplying the acceleration by the estimated inertia value of the controlled object, and
The torque command calculation unit includes a torque feed forward gain ατ , a speed feed forward gain αv, and a position feed that are set based on 1 for each of the model torque τa , model speed va , and model position xa signals from the model signal calculation unit. The actual position xm is based on the position command based on the feedforward control unit that multiplies and outputs the forward gain αx , and the position proportional gain Kx, velocity proportional gain Kv, and position integral gain Ki, which are feedback gains set for disturbance. a feedback control unit for calculating the torque command τr so as to coincide with xr ;
The torque command calculation unit inputs the model torque τa, model speed va, model position xa, actual speed vm, and actual position xm, position proportional gain Kx, speed proportional gain Kv, position integral gain Ki, and torque feed forward. The torque command τr is output based on the calculation represented by the following equation using the gain ατ, the velocity feedforward gain αv, and the position feedforward gain αx.
τr = ατ · τa + Kv · (αv · va−vm) + Kx · (αx · xa−xm) + Ki (1 / s) (xa−xm)
s: Laplace operator The feedforward control unit sets the position feedforward gain αx to the velocity feedforward gain αv so that the disturbance response by the feedback control unit can be kept optimal and compensation for an error between the model and the control target can be performed. And a position control device that can be set to a value other than 1 independently of the feedback gain. A model signal calculation unit that generates signals of model torque τa , model speed va , and model position xa from the input position command xr by assuming the control target as a model and using the inertia estimated value of the control target, and this The model torque τa , model speed va , model position xa signals from the model signal calculation unit, the actual position xm that is the position detection signal of the controlled object, and the actual speed vm signal that is the speed detection signal are input, A torque command calculation unit for generating the torque command τr to be controlled is provided , and an external position command xr, the actual position xm, and the actual speed vm are input and the torque command τr is output, and the actual position xm In the position control device for controlling the control object by generating a torque according to the torque command τr so as to coincide with the position command xr ,
The model signal calculation unit receives the position command xr and calculates a model position xa calculated by a predetermined transfer function calculation, a model speed va that is a differential signal of the model position xa, and a model that is a differential signal of the model speed va. A model torque τa obtained by multiplying the acceleration by the estimated inertia value of the controlled object, and
The torque command calculation unit includes a torque feed forward gain ατ , a speed feed forward gain αv, and a position feed that are set based on 1 for each of the model torque τa , model speed va , and model position xa signals from the model signal calculation unit. The actual position xm is based on the position command based on the feedforward control unit that multiplies and outputs the forward gain αx , and the position proportional gain Kx, velocity proportional gain Kv, and position integral gain Ki, which are feedback gains set for disturbance. a feedback control unit for calculating the torque command τr so as to coincide with xr ;
The torque command calculation unit inputs the model torque τa, model speed va, model position xa, actual speed vm, and actual position xm, position proportional gain Kx, speed proportional gain Kv, position integral gain Ki, and torque feed forward. The torque command τr is output based on the calculation represented by the following equation using the gain ατ, the velocity feedforward gain αv, and the position feedforward gain αx.
τr = ατ · τa + Kv · (αv · va−vm) + Kx · (αx · xa−xm) + Ki (1 / s) (xa−xm)
s: Laplace operator The feedforward control unit is configured so that the position feedforward gain αx and the velocity feedforward gain αv are set so that the disturbance response by the feedback control unit can be maintained optimally and the error between the model and the control target can be compensated. A position control device characterized in that all of the torque feedforward gain ατ can be set to a value other than 1 independently of the feedback gain. A model signal calculation unit that creates signals of model torque τa, model speed va, and model position xa from the input position command xr by assuming the control target as a model and calculating using the inertia estimated value of the control target, and this Each signal of the model torque τa, model speed va, model position xa from the model signal calculation unit, the actual position xm that is the position detection signal of the control target, and each signal of the actual speed vm that is the speed detection signal are input, A torque command calculation unit for generating the torque command τr to be controlled is provided, and an external position command xr, the actual position xm, and the actual speed vm are input and the torque command τr is output, and the actual position xm In the position control device for controlling the control object by generating a torque according to the torque command τr so as to coincide with the position command xr,
The model signal calculation unit receives the position command xr and calculates a model position xa calculated by a predetermined transfer function calculation, a model speed va that is a differential signal of the model position xa, and a model that is a differential signal of the model speed va. A model torque τa obtained by multiplying the acceleration by the estimated inertia value of the controlled object, and
The torque command calculation unit includes a torque feed forward gain ατ, a speed feed forward gain αv, and a position feed that are set based on 1 for each of the model torque τa, model speed va, and model position xa signals from the model signal calculation unit. The actual position xm is based on the position command based on the feedforward control unit that multiplies and outputs the forward gain αx, and the position proportional gain Kx, velocity proportional gain Kv, and position integral gain Ki, which are feedback gains set for disturbance. a feedback control unit for calculating the torque command τr so as to coincide with xr;
The torque command calculation unit inputs the model torque τa, model speed va, model position xa, actual speed vm, and actual position xm, position proportional gain Kx, speed proportional gain Kv, position integral gain Ki, and torque feed forward. The torque command τr is output based on the calculation represented by the following equation using the gain ατ, the velocity feedforward gain αv, and the position feedforward gain αx.
τr = ατ · τa + Kv · (αv · va−vm) + Kx · (αx · xa−xm) + Ki (1 / s) (xa−xm)
s: The Laplace operator feedforward control unit keeps the disturbance response by the feedback control unit optimal and compensates for the error between the model and the controlled object so that the position feedforward gain αx, the speed feedforward gain αv, and the torque feed A position control device characterized in that the forward gain ατ is set using a relational expression independent of the feedback gain . 4. The position control according to claim 3, wherein the feedforward control unit is configured to set the position feedforward gain αx, the speed feedforward gain αv, and the torque feedforward gain ατ using the relationship of the following equation. apparatus.
(Position feedforward gain αx) = (Speed feedforward gain αv)
= (Torque feed forward gain ατ) 4. The position control according to claim 3, wherein the feedforward control unit is configured to set the position feedforward gain αx, the speed feedforward gain αv, and the torque feedforward gain ατ using the relationship of the following equation. apparatus.
(Torque feed forward gain ατ) = (position feed forward gain αx) ³
(Speed feed forward gain αv) = (Position feed forward gain αx) ² The torque command calculation unit is a torque feedforward amplifier that outputs a feedforward torque τf obtained by multiplying the model torque τa by a torque feedforward gain ατ, and a speed that outputs a feedforward speed vf obtained by multiplying the model speed va by a speed feedforward gain αv. A feedforward amplifier, a position feedforward reducer that outputs a feedforward position xf obtained by multiplying the model speed va by a position feedforward reduction gain βx, and the feedforward position xf is subtracted from a deviation between the model position xa and the actual position xm. A position integrator that outputs a signal integrated signal, a speed proportional compensator that outputs a signal obtained by multiplying a deviation between the feedforward speed vf and the actual speed vm by a speed proportional gain Kv, the model position xa and the actual position xm of Position proportional compensator for outputting a multiplied signal of the position proportional gain Kx to the difference, and includes a position integral compensator for outputting a multiplied signal of the position integral gain Ki of the output of the position integrator,
The position feedforward gain αx is set by the following equation, and the addition value of the feedforward torque τf and the output signal of the speed proportional compensator, position proportional compensator, and position integral compensator is output as a torque command τr. The position control device according to claim 1 .
αx = 1−Ki · βx / Kx The position control according to any one of claims 1 to 6, wherein the model signal calculation unit is configured so that a transfer characteristic from the position command to the model position has a low-pass characteristic that cuts a predetermined frequency or more. apparatus.

Images