JPH0829920B2 - Balance cargo handling device control circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention realizes an equilibrium state by outputting a force commensurate with the weight of an arbitrary weight work piece, and a person directly applies a force to the work piece with a light force. The present invention relates to a control circuit of a balanced cargo handling device (a hoisting type, a parallelogram ring type, etc.) that can move up and down.

(Prior Art) As a method of storing the load, as shown in Japanese Patent Application No. 62-152244, after a speed command signal enters within a certain threshold value, that is, after a position mode has been set, a certain time is kept. There was a way to simply average the force sensor signals. (Figs. 5 and 6
Figure) (Problems to be solved by the invention) In order to move a load with a light operating force in an equilibrium state,
It is necessary to remember the load as accurately as possible.

However, when the rigidity of the mechanical unit is low, the work shakes greatly, and therefore the signal contains the acceleration component, and it was necessary to wait until the shake stopped in order to accurately calculate the load. That is, there is a problem in that the operator cannot stop the work during this time because the balance mode cannot be entered until the load is memorized after the lever operation is completed. In order to solve such a problem, the present invention proposes to provide an acceleration sensor in the vicinity of the force sensor, remove the acceleration component from the force sensor signal by the acceleration signal, and time average the signal.

(Means and Actions for Solving the Problem) In order to solve the above problems, the control circuit of the balanced cargo handling apparatus according to the present invention provides an actuator for raising and lowering a load, a drive circuit for driving the actuator, and a load. A force detector for detecting, an acceleration detector mounted close to the force detector, a speed commander for inputting a speed command, and a detection signal of each of the detectors are input and output to an actuator drive circuit. In a balanced cargo handling device equipped with an arithmetic circuit,
By inputting the detection signal FL of the force detector and the detection signal α of the acceleration detector to the weight storage calculation unit in the calculation circuit, the force signal correction value Fa is calculated by the formula Fa = FL / [1+ (α / g )] And by comparing the speed command signal of the speed commander with a predetermined threshold value thereof, it is determined whether or not to calculate the average value of the force signal correction value Fa within a predetermined time,
The control means outputs an average value of the force signal correction value Fa within a predetermined time to the actuator drive circuit.

The control circuit of the equilibrium loading and unloading device controls the force signal correction value Fa within a predetermined time when the speed commander signal is equal to or less than a predetermined threshold value.
Of the force signal correction value Fa and outputs the average value of the force signal correction value Fa to the actuator drive circuit.

Further, the control circuit of the equilibrium cargo handling device calculates the average value of the force signal correction value Fa if the fluctuation of the force signal correction value Fa becomes a predetermined value or less even if the speed commander signal is equal to or more than a predetermined threshold value. Set as the start time.

 In the case of the above-mentioned structure, it operates as follows.

The force signal correction value Fa, which is the true load excluding the inertial force due to acceleration or deceleration, is calculated, and this force signal correction value Fa is calculated.
Since the average value within a predetermined time of is output as the weight storage value from the weight storage calculation unit in the calculation circuit to the actuator drive circuit, the fluctuation of the force signal correction value Fa is small and the weight storage value can be stabilized quickly. The average value within the time is accurate,
And it is required in a short time.

By comparing the speed command signal of the speed commander and its predetermined threshold value, the lever mode for operating the speed commander is terminated and the position mode is reached in which the work is held at the position where the speed commander is stopped. When the position mode is entered, the average value of the force signal correction value Fa within a predetermined time is calculated immediately, so the average value of the force signal correction value Fa is stored as a weight storage value. The time T _R2 , T _R3 can be shortened to the required minimum, the weight storage of the load is completed quickly, and this weight storage value is output to the actuator drive circuit, so that the load can be operated immediately at the position where the speed commander was operated. To be done.

In the control circuit of the equilibrium loading and unloading device, when the speed commander signal becomes equal to or less than a predetermined threshold value, it is determined that the operation of the speed commander is completed and the lever mode is changed to the position mode, and immediately the force signal correction value Fa for calculation of the average value in a predetermined time period is started, in early to complete the time to store T _R2 a mean value of the force signal correction Fa as weight stored value, outputting the weight values stored in the actuator drive circuit By doing so, it is possible to immediately operate the load at the position where the speed command device was operated.

Further, in the control circuit of the equilibrium loading and unloading device, even if the speed commander signal is equal to or higher than a predetermined threshold because the speed commander is operating (lever mode), the fluctuation of the force signal correction value Fa becomes small and the force signal If the fluctuation of the correction value Fa becomes less than or equal to a predetermined value, even if the calculation of the average value of the force signal correction value Fa is started, the average value of the weight storage value within the predetermined time is accurately obtained,
Force signal correction value in the position mode, which should be added to the calculation time of the average value of the force signal correction value Fa in the lever mode
By completing the time T _R3 for storing the average value of Fa as the weight storage value earlier and outputting this weight storage value to the actuator drive circuit, the load can be immediately operated to the position where the speed commander was operated. You can also

(Example) As shown in FIG. 2, assuming that the force sensor signal is F, the acceleration signal is a, the power acceleration is g (the direction of each arrow is positive), and the work weight is W, _FL = W + (W / g) × a = (1 + a / g) × W. Therefore, the acceleration component can be removed from the force sensor signal by dividing the force sensor signal by (1 + a / g).

When the speed command from the lever enters within a certain threshold,
In other words, when entering position mode from lever mode,
By obtaining the time average of _{F L / (1 + a /} g) ( referred to as a force sensor signal compensation signal Fa), much faster than conventional methods, it is possible to accurately store load.

Further, as shown in FIG. 3, when the load is conveyed by operating the lever, the load shakes most and the force sensor signal also fluctuates greatly.
Therefore, in the prior art, it is impossible to store the weight during the lever operation, but the correction signal Fa shows a value almost equal to the load W immediately after the load is lifted from the ground even during the lever operation.

The structure of the present invention is shown in FIG. 1. An actuator 1 for raising and lowering a work, the same drive circuit 2, the same actuator speed detector 7, the same actuator position detector 6, and force detection in the portion where the work is suspended. A device 5 and a speed command device 3 (for lever operation) are provided. The arithmetic circuit 10 has a speed command value R,
Actuator speed signal v, same position signal x, force signal 4
A signal is input. Inside the arithmetic circuit 10, there are a lever mode arithmetic unit 11, a position mode arithmetic unit 12, and a balance mode arithmetic unit.
13, the balance static mode operation unit 14 is a mode selection circuit 16
Is selected as appropriate and is input to the actuator drive circuit 2. The actuator speed signal v is differentiated by the differentiating circuit 8 regardless of the mode. The calculation circuit 10 has a weight storage calculation unit 15 and stores the weight storage value stored in the calculation unit.
W ₀ is used by the balance mode calculation unit 13, the balance stationary mode calculation unit 14, and the mode selection calculation unit 16.

 The contents of each mode are shown below.

B) Lever mode The speed command value R and the actuator speed v are input, and K _R × R−Kvn × v is calculated and input. Allows the operator to control the speed by operating the lever.

B) Position mode The actuator speed v and position x are input, and the position X ₀ when the position mode is entered is stored, and Kx × (x ₀ −x) −Kvn × v is calculated and output. Allows the work to be held at that position after the lever operation is completed.

C) the balance mode force signal F _L, actuator velocity v, and the weight stored value W ₀ is _{input, K F × (W 0 -F} L) + Kvp × v is calculated and output. Allows the operator to directly apply a force to the work to lift and lower even heavy objects with a light force.

D) balance quiescent mode force signal F _L, weight stored value W _0, actuator position x is input, also stores the position x ₀ of when they are balanced quiescent _{mode, K F × (W 0 -F} L) + K _X × (x ₀ −x) is calculated and output. The work can be stopped when the operator's hand is released.

Next, the selection circuit 16 for selecting the above four modes will be described. The selection circuit 16, the speed command value R, the force signal F _L, the weight stored value W ₀ is input, the mode is selected according to the flowchart of FIG. 4.

 Incidentally, FIG. 5 shows a mode transition diagram (conventional plan).

The present invention relates to the weight storage circuit 15 described above.
FIG. 6 shows the configuration of the conventional scheme. Conventionally only a force signal F _L is inputted, it was calculated the weight from the time average of the force signal F _L storage. In contrast, the accelerometer 4 in the vicinity of the force detector 5 provided in the present invention, type force signal F _L and the acceleration signal a, proposes to correct the force signal F _L with the acceleration signal a.

Force signal F _L, in order to detect, as shown in FIGS. 2 and 3 (workpiece weight) + (acceleration force), thus highly variable when obtained by lifting the workpiece with lever operation. Therefore, according to the conventional method, if the average value of a long time (T _R1 ) is not taken after the lever operation is finished, as shown in the figure, the accuracy becomes poor.

However, as shown in FIG. _{2, F L = (1 + a} / g) because it is × W, if dividing the force signal F _L by (1 + a / g), the workpiece weight W obtained by removing the acceleration component from the force signal Should be able to be detected. Accordingly moved to position mode finished lever mode, by obtaining the time average of _{F L / (1 + a /} g) ( referred to as a force signal correction signal Fa) and (T _R2), compared with the conventional method as shown in FIG. 3 The load can be calculated quickly and accurately.
Further, according to the conventional proposal, the load is most shaken during the lever operation, and the fluctuation of the force signal is large, so that the weight cannot be stored unless the position mode is entered after the lever operation. If the correction signal Fa is used, as shown in FIG. 3, once the load floats from the ground even while the lever is being operated, the load becomes almost equal to the load W immediately. Therefore, if the fluctuation of the correction signal Fa during lever operation becomes small (t _{A in} FIG. 3) to T _R3 after lever operation, it is possible to obtain this with high accuracy by obtaining the T _R4 time average, Moreover, the time T _R3 from lever operation to completion of memory can be further shortened.

Although the embodiment shown in FIG. 1 is a winding type elevator,
The same applies to a parallelogram type elevator as shown in FIG. Further, the invention is not limited to the electric type and can be applied to pneumatic and hydraulic lifts.

The work is hung by a rope and wound up by a motor. AC or DC servo motor is usually used for the motor. A resolver, a tacho-generator or the like is used as the speed detector 7, and an encoder or a resolver or the like is used as the position detector 6.

As the force detector 5, a general load cell or the like can be used, and is attached to the portion where the work is suspended. As the speed command device 3, a method in which the tilt angle of the lever is detected by a potentiometer is usually used, and the speed command is determined depending on the tilt angle of the lever. The speed command signal R is smoothed by the primary delay circuit 9. The actuator speed v, the actuator position x, the force detection signal _FL , and the speed command value R ', which are the four signals (referred to as R'), are used in the arithmetic circuit
Entered in 10. As the arithmetic circuit, a digital arithmetic unit is usually used, and thus an A / D converter converts it to digital. In the digital calculator, the mode is decided first.

 The flowchart is as shown in FIG.

Next, FIG. 8 shows a flowchart for the weight storage method of the present invention. As shown in FIG. 8, the calculation of the weight storage is performed at the time T _R2 after the end of the lever mode, and T _R2 is added to the addition register (Fa-sum).

When T _R2 has passed, the addition register is divided by the counter to obtain the average value of the force sensor correction signal, which is input to the storage value register W ₀ , storage is completed, and the balance mode can be entered.

Next, FIG. 9 shows a flowchart of the second embodiment of the present invention (a method for further shortening the storage time). The present embodiment is characterized in that the calculation of the weight storage is started in the lever mode and when the fluctuation of the force sensor correction signal Fa becomes small. It should be noted that the storage is completed after a certain time T _R3 from the end of the lever mode and the start of the position control as in the case of FIG. 8, but it is obviously much shorter than the above T _R2 .

(Effects of the Invention) Since the control circuit of the balanced cargo handling apparatus according to the present invention is configured as described above, (1) the fluctuation of the force signal correction value Fa is small and it stabilizes quickly. Since the average value of is accurately calculated in a short time, the load is immediately operated at the position where the speed commander is operated, and the workability can be improved.

(2) By comparing the speed command signal of the speed commander with its predetermined threshold value, when the lever mode ends and the position mode is entered, the force signal correction value Fa is immediately calculated as an average value within a predetermined time. Since the calculation is started, the speed commander was operated by ending the time for storing the average value of the force signal correction value Fa as the weight storage value early and outputting this weight storage value to the actuator drive circuit. The load is immediately operated to the position, and workability can be improved also from this aspect.

(3) Even if the speed commander is in operation, if the fluctuation of the force signal correction value Fa becomes small, the calculation of the average value of the force signal correction value Fa is started from the lever mode before the position mode. Then, the calculation time of the average value of the force signal correction value Fa in the position mode can be further shortened, the load memory of the load can be completed quickly, and if this weight memory value is output to the actuator drive circuit, the speed commander was operated. Since the load is immediately operated to the position, workability can be further improved.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention. FIG. 2 is an explanatory diagram of a force sensed by a force sensor. FIG. 3 is a comparison diagram of a conventional method and the present invention (average signal and average time). Is a mode selection decision flow chart. Fig. 5 is a mode transition diagram (conventional plan). Fig. 6 is an overall configuration diagram of the conventional plan. Fig. 7 is an example of a parallelogram-link type balanced cargo handling device. Fig. 8 is the first of the present invention. 9 is a flowchart of a second embodiment of the present invention. 1 ... actuator 2 ... actuator drive circuit 3 ... speed commander 4 ... acceleration detector 5 ... force detector 6 ... position detector 7 …… Speed detector 8 …… Differentiator 9 …… First-order lag circuit 10 …… Calculator circuit 11 …… Lever mode calculator 12 …… Position mode calculator 13 …… Balance mode calculator 14 …… Balance stationary mode calculator 15 …… Weight storage mode calculator 16 …… Over mode selection calculation unit

Claims (3)

[Claims] 1. An actuator for raising and lowering a load, a drive circuit for driving the actuator, a force detector for detecting the load, an acceleration detector mounted in proximity to the force detector, and a speed command input. In the equilibrium loading and unloading apparatus equipped with the speed commander and the arithmetic circuit for inputting the detection signals of the respective detectors and outputting them to the actuator drive circuit, the detection signal FL of the force detector and the detection signal α of the acceleration detector are By inputting and to the weight storage calculation unit in the calculation circuit, the force signal correction value Fa is calculated by the formula Fa = FL / [1+ (α / g)], and the speed command signal of the speed commander and its By comparing with a predetermined threshold, to determine whether to calculate the average value of the force signal correction value Fa within a predetermined time,
A control circuit for a balanced cargo handling apparatus, comprising control means for outputting an average value of the force signal correction value Fa within a predetermined time to the actuator drive circuit. 2. The control circuit for a balanced cargo handling apparatus according to claim 1, wherein an average value of the force signal correction values Fa within a predetermined time when the speed commander signal is below a predetermined threshold value is calculated, and this force is calculated. A control circuit for a balanced cargo handling apparatus, comprising control means for outputting an average value of the signal correction value Fa to the actuator drive circuit. 3. The control circuit for a balanced cargo handling apparatus according to claim 1, wherein even if the speed commander signal is equal to or more than a predetermined threshold value, if the fluctuation of the force signal correction value Fa is less than or equal to a predetermined value, A control circuit for a balanced cargo handling device, characterized in that the calculation start time of the average value of the force signal correction value Fa is set.