JP7621101B2 - Control device, electric power steering device, steer-by-wire system - Google Patents

Description

The present invention relates to a control device, an electric power steering device, and a steer-by-wire system.

For example, the electric power steering device described in Patent Document 1 includes a steering angle reaction force compensation current calculation unit that calculates a steering angle reaction force compensation current, which is a current for the electric motor to provide a steering reaction force that depends on the steering angle, and a final target current determination unit that determines a target current to be supplied to the electric motor in consideration of the steering angle reaction force compensation current. The steering angle reaction force compensation current calculation unit includes an absolute value calculation unit that calculates the absolute value of the actual steering angle, and a steering angle correction unit that corrects the absolute value of the actual steering angle by adding a predetermined value to the absolute value of the actual steering angle. The steering angle reaction force compensation current calculation unit also includes a provisional compensation current calculation unit that calculates a provisional steering angle reaction force compensation current based on the corrected steering angle and a predetermined control map, and a sign setting unit that sets the sign of the steering angle reaction force compensation current based on the operation direction of the steering wheel.

JP 2014-136479 A

The shape of the angle-force characteristic shown by the correlation between the steering torque and the steering angle affects the steering feeling.
Although Patent Document 1 describes that it is effective near the neutral position, it does not describe the effect on the shape of the angle-force characteristics.
An object of the present invention is to provide a control device and the like that can realize a desired steering feeling by controlling the shape of the angle-force characteristic.

To this end, the present invention provides a control device that includes a target control amount calculation unit that calculates a target control amount based on the value of a steering input signal from a driver, an elastic component calculation unit that calculates an elastic reaction force component that simulates elasticity based on a steering angle, a reaction force component calculation unit that calculates a reaction force component based on the elastic reaction force component, and a correction unit that corrects at least one of the value of the steering input signal or the target control amount based on the reaction force component.

The present invention allows you to control the shape of the angle-force characteristics to achieve the desired steering feeling.

1 is a schematic configuration diagram illustrating an example of an electric power steering device according to a first embodiment. FIG. 2 is a schematic diagram illustrating an example of a control device. FIG. 2 is a diagram showing an example of angle-force characteristics in a steering device. FIG. 11 is a schematic configuration diagram illustrating an example of a steering device according to a second embodiment. FIG. 2 is a diagram showing an example of angle-force characteristics in a steering device. FIG. 13 is a schematic configuration diagram illustrating an example of a steering device according to a third embodiment. FIG. 13 is a schematic configuration diagram illustrating an example of a steering device according to a fourth embodiment. FIG. 13 is a schematic configuration diagram illustrating an example of a steering device according to a fifth embodiment. FIG. 13 is a schematic configuration diagram illustrating an example of a steering device according to a sixth embodiment. FIG. 13 is a schematic configuration diagram illustrating an example of a steering device according to a seventh embodiment. FIG. 23 is a schematic configuration diagram illustrating an example of a steering device according to an eighth embodiment. FIG. 13 is a schematic configuration diagram illustrating an example of a steering device according to a ninth embodiment. FIG. 23 is a diagram showing an example of a schematic configuration of a steer-by-wire system according to a tenth embodiment. 4 is a schematic configuration diagram showing an example of a reaction motor control unit that controls driving of a reaction motor in the control device. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
First Embodiment
FIG. 1 is a schematic diagram showing an example of an electric power steering device 100 according to a first embodiment.
An electric power steering device 100 (hereinafter, sometimes simply referred to as "steering device 100") is a steering device for arbitrarily changing the traveling direction of a vehicle, and in this embodiment, a configuration applied to an automobile 1 as an example of a vehicle is illustrated. Note that Fig. 1 is a view of the automobile 1 as seen from the front.

The steering device 100 includes a wheel-shaped steering wheel 101 that is operated by the driver to change the direction of travel of the automobile 1, and a steering shaft 102 that is integral with the steering wheel 101. The steering device 100 also includes an upper connecting shaft 103 that is connected to the steering shaft 102 via a universal joint 103a, and a lower connecting shaft 108 that is connected to the upper connecting shaft 103 via a universal joint 103b. The lower connecting shaft 108 rotates in conjunction with the rotation of the steering wheel 101.

The steering device 100 also includes a tie rod 104 connected to each of the left and right wheels 150 as rolling wheels, and a rack shaft 105 connected to the tie rod 104. The steering device 100 also includes a pinion 106a that constitutes a rack-pinion mechanism together with rack teeth 105a formed on the rack shaft 105. The pinion 106a is formed on the lower end of the pinion shaft 106. The pinion shaft 106 applies a driving force (rack shaft force) to the rack shaft 105 to rotate and cause the left and right wheels 150 to roll.

The steering device 100 also has a steering gear box 107 that houses the pinion shaft 106. The pinion shaft 106 is connected to a lower connecting shaft 108 via a torsion bar 112 inside the steering gear box 107. A torque sensor 109 is provided inside the steering gear box 107 to detect steering torque, which is an example of a steering input applied to the steering wheel 101, based on the relative rotation angle between the lower connecting shaft 108 and the pinion shaft 106, in other words, based on the amount of twist of the torsion bar 112.

The steering device 100 also has an electric motor 110 supported by a steering gear box 107, and a speed reducing mechanism 111 that reduces the driving force of the electric motor 110 and transmits it to the pinion shaft 106. The speed reducing mechanism 111 has a worm wheel 111a fixed to the pinion shaft 106, and a worm 111b connected to the output shaft of the electric motor 110 via a shaft coupling (not shown). The electric motor 110 applies a driving force (rack shaft force) that rotates the wheels 150 to the rack shaft 105 by applying a rotational driving force to the pinion shaft 106. The electric motor 110 according to this embodiment can be exemplified as a three-phase brushless motor having a resolver 120 that outputs a rotation angle signal θms linked to the rotation angle θm of the electric motor 110.

The steering device 100 also includes a control device 10 that controls the operation of the electric motor 110. The control device 10 receives an output signal from the torque sensor 109 described above. The control device 10 also receives an output signal v from a vehicle speed sensor 170 that detects the vehicle speed Vc, which is the moving speed of the automobile 1, via a communication network (CAN) that transmits signals for controlling various devices mounted on the automobile 1.

(Control device)
Next, the control device 10 will be described.
FIG. 2 is a schematic diagram showing an example of the control device 10. As shown in FIG.
The control device 10 is an arithmetic and logic circuit including a CPU, a ROM, a RAM, a backup RAM, and the like.
The control device 10 receives output signals from the torque sensor 109, the vehicle speed sensor 170, the resolver 120, and the like. The output signal from the torque sensor 109 is an example of a driver's steering input signal, and the detected torque Td, which is the steering torque detected by the torque sensor 109, is an example of a value of the driver's steering input signal.

The control device 10 includes a target current setting unit 20 that sets a target current It required to be supplied to the electric motor 110, and a control unit 30 that performs feedback control, etc. based on the target current It calculated by the target current setting unit 20.
The control device 10 also includes a rotation angle calculation unit 41 that calculates the rotation angle θm of the electric motor 110, and a steering angle calculation unit 42 that calculates the steering angle θs, which is the rotation angle of the steering wheel 101, based on the rotation angle θm calculated by the rotation angle calculation unit 41.
The control device 10 also includes a torque correction unit 50 that corrects the detected torque Td, which is the steering torque detected by the torque sensor 109, to calculate a corrected torque Tc.

[Target current setting unit]
The target current setting unit 20 sets the target current It based on the corrected torque Tc calculated by the torque correction unit 50 and the vehicle speed Vc. When the corrected torque Tc is positive, the target current setting unit 20 sets the target current It to positive, and when the corrected torque Tc is negative, the target current It to negative. When the corrected torque Tc is 0, the target current setting unit 20 sets the target current It to 0, and increases the absolute value of the target current It as the absolute value of the corrected torque Tc increases. When the absolute value of the corrected torque Tc is the same, the target current setting unit 20 can be exemplified as increasing the absolute value of the target current It as the vehicle speed Vc decreases. The target current setting unit 20 may set a dead band region in which the target current It is 0 regardless of the value of the corrected torque Tc.

[Control Unit]
The control unit 30 has a drive control unit (not shown) that controls the operation of the electric motor 110, a drive unit (not shown) that drives the electric motor 110, and a current detection unit (not shown) that detects the actual current actually flowing through the electric motor 110.

The drive control unit performs feedback control based on the deviation between the target current It set by the target current setting unit 20 and the actual current supplied to the electric motor 110 detected by the current detection unit.
The drive unit is a so-called inverter, and includes, for example, six independent transistors (FETs) as switching elements.

[Rotation angle calculation unit, steering angle calculation unit]
The rotation angle calculation unit 41 calculates the rotation angle θm based on the output signal from the resolver 120 .
Considering that there is a correlation between the rotation angle of the steering wheel 101 and the rotation angle θm of the electric motor 110, the steering angle calculation unit 42 calculates the steering angle θs based on the rotation angle θm calculated by the rotation angle calculation unit 41. The steering angle calculation unit 42 calculates the steering angle θs based on, for example, an integrated value of the difference between the previous value and the current value of the rotation angle θm calculated periodically (for example, every 1 millisecond) by the rotation angle calculation unit 41.

Here, the direction in which the relative rotation angle between the steering wheel 101 and the pinion shaft 106 changes when the steering wheel 101 is rotated to the right from a state in which the torsion amount of the torsion bar 112 is zero (neutral state) is considered to be positive. In other words, the steering torque is positive. Also, the direction in which the relative rotation angle between the steering wheel 101 and the pinion shaft 106 changes when the steering wheel 101 is rotated to the left from the neutral state is considered to be negative. In other words, the steering torque is negative.

The direction in which the target current It flows, calculated by the target current setting unit 20 so as to rotate the electric motor 110 in the clockwise direction, is defined as positive. For example, when the corrected torque Tc is positive, the target current setting unit 20 calculates a positive target current It, and generates torque in a direction that rotates the electric motor 110 in the clockwise direction. When the corrected torque Tc is negative, the target current setting unit 20 calculates a negative target current It, and generates torque in a direction that rotates the electric motor 110 in the counterclockwise direction.
In addition, when the steering wheel 101 is rotated to the right from a state in which the steering angle θs is 0 degrees, the steering angle θs becomes positive, and when the steering wheel 101 is rotated to the left, the steering angle θs becomes negative.

[Torque correction section]
The torque correction unit 50 has a deviation calculation unit 51 that calculates a deviation Δθ of the steering angle θs, and a reaction force component calculation unit 52 that calculates a reaction force component against the steering by the driver based on the deviation Δθ calculated by the deviation calculation unit 51. The torque correction unit 50 also has a correction unit 53 that corrects the detected torque Td by using the reaction force component calculated by the reaction force component calculation unit 52.

The deviation calculation unit 51 calculates the deviation Δθ by subtracting the previously acquired value of the steering angle θs, which is periodically acquired from the steering angle calculation unit 42, from the currently acquired value (Δθ=θs (currently acquired value)-θs (previously acquired value)).

The reaction force component calculation unit 52 has an elastic component calculation unit 55 that calculates an elastic reaction force torque Te based on the deviation Δθ calculated by the deviation calculation unit 51. The electric motor 110 and the wheels 150 are connected via a transmission mechanism 130 (see FIG. 1 ) that is composed of a reduction gear mechanism 111, a pinion shaft 106, a rack shaft 105, a tie rod 104, etc., and the driving force of the electric motor 110 is transmitted to the wheels 150 via the transmission mechanism 130. The elastic component calculation unit 55 takes into account the elasticity of the transmission mechanism 130 and calculates an elastic reaction force torque Te against the steering by the driver, which is caused by the elasticity, based on the following formula (1).
Te=Kt×Δθ...(1)
Kt is a predetermined proportionality constant.
The elastic reaction torque Te is an example of an elastic reaction component that simulates elasticity based on the steering angle θs. The reaction component calculation unit 52 according to the first embodiment outputs the elastic reaction torque Te calculated by the elastic component calculation unit 55 to the correction unit 53 as a reaction component.

The correction unit 53 calculates a corrected torque Tc by subtracting the elastic reaction torque Te output from the reaction force component calculation unit 52 from the detected torque Td detected by the torque sensor 109 (Tc=Td−Te).
As described above, the torque correction unit 50 calculates the corrected torque Tc. Then, the target current setting unit 20 sets the target current It using the corrected torque Tc.

(Action)
The steering device 100 configured as above operates as follows.
Fig. 3 is a diagram showing an example of angle-force characteristics in the steering device 100. Fig. 3 is a characteristic diagram showing a case where slalom driving is performed after the steering wheel 101 is turned to the right. Hereinafter, a configuration in which the torque correction unit 50 is not provided in comparison with the control device 10 according to the first embodiment, and the target current setting unit 20 sets the target current It using the detected torque Td, may be referred to as a steering device according to a comparative example.

For example, when the steering wheel 101 is turned to the right, the deviation Δθ becomes large, and the elastic reaction torque Te becomes a positive value. Therefore, the corrected torque Tc becomes smaller than the detected torque Td. On the other hand, when the steering wheel 101 is turned to the left, the deviation Δθ becomes small, and the elastic reaction torque Te becomes a negative value. Therefore, the corrected torque Tc becomes larger than the detected torque Td. As a result, when the steering wheel 101 is turned, the absolute value of the target current It becomes smaller than in the comparative example, and the assist force by the electric motor 110 becomes smaller, and the absolute value of the steering force by the driver becomes larger.

On the other hand, when the steering wheel 101 is turned to the right and then turned back, the deviation Δθ becomes smaller, and the elastic reaction torque Te becomes a negative value. Therefore, the corrected torque Tc becomes larger than the detected torque Td, and the target current It becomes larger than in the comparative example. As a result, when the steering wheel 101 is turned to the right and then turned back, the target current It becomes larger than in the comparative example, so that the assist force by the electric motor 110 becomes larger and the steering force of the driver becomes smaller.

On the other hand, when the steering wheel 101 is turned leftward and then turned back, the deviation Δθ becomes large, and the elastic reaction torque Te becomes a positive value. Therefore, the corrected torque Tc becomes smaller than the detected torque Td, and the target current It becomes smaller than in the comparative example. As a result, when the steering wheel 101 is turned leftward and then turned back, the target current It becomes smaller than in the comparative example, so the assist force by the electric motor 110 becomes smaller and the steering force of the driver becomes larger.

As described above, the control device 10 includes the target current setting unit 20 as an example of a target control amount calculation unit that calculates the target current It as an example of a target control amount based on the value of the driver's steering input signal, and the reaction force component calculation unit 52 that has the elastic component calculation unit 55 that calculates the elastic reaction force torque Te simulating elasticity based on the steering angle θs and calculates the elastic reaction force torque Te as an example of a reaction force component based on the elastic reaction force torque Te. In the control device 10, the reaction force component calculation unit 52 uses the elastic reaction force torque Te calculated by the elastic component calculation unit 55 as a reaction force component. The control device 10 also includes a correction unit 53 that corrects the detection torque Td as an example of the value of the driver's steering input signal based on the elastic reaction force torque Te.
As described above, the steering device 100 can have a larger hysteresis width than the steering device according to the comparative example, as shown in Fig. 3. As a result, the driver can easily maintain the steering angle during cornering, improving the steering feeling during cornering.

The correction unit 53 of the torque correction unit 50 may calculate the corrected torque Tc by adding the detected torque Td detected by the torque sensor 109 and the elastic reaction torque Te calculated by the reaction component calculation unit 52 (Tc = Td + Te). As a result, when the steering wheel 101 is turned, the absolute value of the target current It becomes larger than in the comparative example, so that the assist force by the electric motor 110 becomes larger and the absolute value of the steering force of the driver becomes smaller. In this way, with this configuration, the load when the steering wheel 101 is turned can be reduced, and the steering feeling can be improved in all steering ranges.

The deviation calculation unit 51 of the torque correction unit 50 calculates the deviation Δθ based on the steering angle θs calculated by the steering angle calculation unit 42, but is not limited to this. The deviation Δθ may be calculated based on the output value from a steering angle sensor provided in the steering device 100 that detects the steering angle θs.

Second Embodiment
FIG. 4 is a schematic configuration diagram showing an example of a steering device 200 according to the second embodiment.
The steering device 200 according to the second embodiment is different from the steering device 100 according to the first embodiment in the control device 10. Below, the differences from the steering device 100 according to the first embodiment will be described, and the description of the same points as the steering device 100 according to the first embodiment will be omitted.

The control device 210 according to the second embodiment includes a target current setting unit 220 that sets a target current It to be supplied to the electric motor 110 , and a control unit 30 .
The target current setting unit 220 includes a basic setting unit 221 that sets a basic target current Ib that is the basis for setting the target current It, and a correction setting unit 222 that sets a correction current that corrects the basic target current Ib. The target current setting unit 220 also includes a final setting unit 223 that sets the target current It that is finally supplied to the electric motor 110.

The basic setting unit 221 sets the basic target current Ib based on the detected torque Td and the vehicle speed Vc. The method by which the basic setting unit 221 sets the basic target current Ib is similar to the method by which the target current setting unit 20 according to the first embodiment sets the target current It, and therefore a detailed description thereof will be omitted.

The correction setting section 222 includes a deviation calculation section 51 and a reaction force component calculation section 252 that calculates a reaction force component based on the deviation Δθ calculated by the deviation calculation section 51 .
The reaction force component calculation unit 252 has an elastic component calculation unit 255 that calculates an elastic correction current Ie based on the deviation Δθ. The elastic component calculation unit 255 calculates an elastic correction current Ie for the driver's steering caused by the elasticity, taking into account the elastic element of the steering device 100, based on the following formula (2).
Ie=Ki×Δθ...(2)
Ki is a predetermined proportionality constant.
The elasticity correction current Ie is an example of an elastic reaction force component that simulates elasticity based on the steering angle θs. The reaction force component calculation unit 252 according to the second embodiment outputs the elasticity correction current Ie calculated by the elasticity component calculation unit 255 to the final setting unit 223.

The final setting unit 223 calculates the target current It by subtracting the elastic correction current Ie set by the correction setting unit 222 from the basic target current Ib set by the basic setting unit 221 (It = Ib - Ie).

(Action)
The steering device 200 configured as above operates as follows.
Fig. 5 is a diagram showing an example of angle-force characteristics in the steering device 200. Fig. 5 is a characteristic diagram showing a case where slalom driving is performed after the steering wheel 101 is turned to the right.
For example, when the steering wheel 101 is turned to the right, the deviation Δθ becomes large, and therefore the elastic correction current Ie has a positive value. Therefore, the target current It becomes smaller than the basic target current Ib. On the other hand, when the steering wheel 101 is turned to the left, the deviation Δθ becomes small, and therefore the elastic correction current Ie has a negative value. Therefore, the target current It becomes larger than the basic target current Ib. As a result, when the steering wheel 101 is turned, the absolute value of the target current It becomes smaller than that of the comparative example, and therefore the assist force by the electric motor 110 becomes smaller, and the absolute value of the steering force by the driver becomes larger.

In addition, when the steering wheel 101 starts to be turned to the right, the deviation Δθ is larger than at the end of the turn, and the elastic correction current Ie is larger. Therefore, the difference between the target current It and the basic target current Ib is larger at the start of the turn than at the end of the turn, so the difference between the driver's steering force and the comparative example is larger at the start of the turn than at the end of the turn. On the other hand, when the steering wheel 101 starts to be turned to the left, the deviation Δθ is smaller than at the end of the turn, and the elastic correction current Ie is smaller. Therefore, the difference between the target current It and the basic target current Ib is larger at the start of the turn than at the end of the turn, so the difference between the driver's steering force and the comparative example is larger at the start of the turn than at the end of the turn.

On the other hand, when the steering wheel 101 is turned to the right and then turned back, the deviation Δθ becomes smaller, so the elastic correction current Ie becomes a negative value. Therefore, the target current It becomes larger than the basic target current Ib, and the assist force by the electric motor 110 becomes larger, so the driver's steering force becomes smaller than in the comparative example. On the other hand, when the steering wheel 101 is turned to the left and then turned back, the deviation Δθ becomes larger, so the elastic correction current Ie becomes a positive value. Therefore, the target current It becomes smaller than the basic target current Ib, and the assist force by the electric motor 110 becomes larger, so the driver's steering force becomes smaller than in the comparative example.

As described above, the control device 210 includes a basic setting unit 221 as an example of a target control amount calculation unit that calculates a basic target current Ib as an example of a target control amount based on the value of the driver's steering input signal, and an elastic component calculation unit 255 that calculates an elastic correction current Ie that simulates elasticity based on the steering angle θs, and a reaction force component calculation unit 252 that calculates an elastic correction current Ie as an example of a reaction force component based on the elastic correction current Ie. In the control device 210, the reaction force component calculation unit 252 uses the elastic correction current Ie calculated by the elastic component calculation unit 255 as a reaction force component. The control device 210 also includes a final setting unit 223 as an example of a correction unit that corrects the basic target current Ib based on the elastic correction current Ie.

As described above, the steering device 200 can have a larger hysteresis width than the steering device of the comparative example, as shown in FIG. 5. Also, the steering device 200 can have a larger difference from the steering device of the comparative example at the start of turning than at the end of turning, as shown in FIG. 5. In other words, the smaller the steering angle θs, the greater the influence, and the larger the steering angle θs, the smaller the influence. Therefore, the setting can be made with more consideration given to the steering feeling at the start of turning than at the end of turning.

The final setting unit 223 may calculate the target current It by adding the basic target current Ib set by the basic setting unit 221 and the elastic correction current Ie set by the correction setting unit 222 (It = Ib + Ie). As a result, when the steering wheel 101 is being turned, the absolute value of the target current It becomes larger than that of the comparative example, so that the assist force of the electric motor 110 becomes larger and the absolute value of the steering force of the driver becomes smaller. In this way, with this configuration, the steering load when the steering wheel 101 is being turned can be reduced. In addition, the difference with the steering device according to the comparative example can be made larger at the start of turning than at the end of turning, so that the steering load can be set to be smaller at the start of turning than at the end of turning.

Third Embodiment
FIG. 6 is a schematic diagram showing an example of a steering device 300 according to the third embodiment.
The steering device 300 according to the third embodiment is different from the steering device 100 according to the first embodiment in the torque correction unit 50 of the control device 10. Below, the points that are different from the steering device 100 according to the first embodiment will be described, and the description of the points that are the same as the steering device 100 according to the first embodiment will be omitted.

The torque correction unit 350 of the control device 310 according to the third embodiment has a deviation calculation unit 51, a reaction force component calculation unit 352, and a correction unit 53. The reaction force component calculation unit 352 has a first elastic component calculation unit 361, a second elastic component calculation unit 362, and a third elastic component calculation unit 363, which are multiple (three in this embodiment) elastic component calculation units that calculate an elastic reaction force component against the steering by the driver based on the deviation Δθ calculated by the deviation calculation unit 51. The reaction force component calculation unit 352 also has an addition unit 370 that adds up the elastic reaction force components calculated by the first elastic component calculation unit 361, the second elastic component calculation unit 362, and the third elastic component calculation unit 363.

The first elastic component calculation unit 361 calculates a first elastic reaction torque Te1 as an example of an elastic reaction component based on the following formula (3) when 0≦Δθ≦θ1, and outputs the calculated value to the adder 370. The second elastic component calculation unit 362 calculates a second elastic reaction torque Te2 as an example of an elastic reaction component based on the following formula (4) when θ1<Δθ≦θ2, and outputs the calculated value to the adder 370. The third elastic component calculation unit 363 calculates a third elastic reaction torque Te3 as an example of an elastic reaction component based on the following formula (5) when θ2<Δθ, and outputs the calculated value to the adder 370.
Te1=Kt1×Δθ...(3)
Te2=Kt2×Δθ...(4)
Te3=Kt3×Δθ...(5)
Furthermore, the first elastic component calculation unit 361 outputs Te1=Kt1×θ1 as an example of a predetermined fixed value when θ1<Δθ, and the second elastic component calculation unit 362 outputs Te2=Kt2×θ2 as an example of a predetermined fixed value when θ2<Δθ.

Kt1, Kt2, and Kt3 are predetermined proportional constants. Kt1, Kt2, and Kt3 may be the same or different. θ1 and θ2 are predetermined values, and θ1<θ2. θ1 and θ2 can be, for example, 10° and 20°, respectively. The ranges of Δθ using the above formulas (3), (4), and (5) may be set so as not to overlap with each other, or may be set so as to overlap with each other.
The number of elastic component calculation units is not limited to three.

The adder 370 outputs the elastic reaction torque Te (Te = Te1 + Te2 + Te3) obtained by adding the first elastic reaction torque Te1 output by the first elastic component calculation unit 361, the second elastic reaction torque Te2 output by the second elastic component calculation unit 362, and the third elastic reaction torque Te3 output by the third elastic component calculation unit 363 to the correction unit 53.
As described above, the reaction force component calculation unit 352 according to the third embodiment calculates the elastic reaction force torque Te as an example of a reaction force component based on the first elastic reaction force torque Te1, the second elastic reaction force torque Te2, and the third elastic reaction force torque Te3 calculated by the first elastic component calculation unit 361, the second elastic component calculation unit 362, and the third elastic component calculation unit 363, and outputs the calculated elastic reaction force torque Te to the correction unit 53.

In the steering device 300 according to the third embodiment configured as described above, as with the steering device 100 according to the first embodiment, the hysteresis width is larger than that of the steering device according to the comparative example, and therefore the steering feeling during cornering is improved. In addition, according to the steering device 300 according to the third embodiment, the values of Te1, Te2, and Te3 can be adjusted by changing the values of Kt1, Kt2, Kt3, and θ1 and θ2, so that a finely tuned steering feeling can be set, and as a result, the steering feeling for the driver can be improved.

Furthermore, the first elastic component calculation unit 361 outputs Te1 = Kt1 x θ1 when θ1 < Δθ, and the second elastic component calculation unit 362 outputs Te2 = Kt2 x θ2 when θ2 < Δθ. As a result, the value output from the reaction force component calculation unit 352 increases as Δθ increases. Therefore, the steering device 300 can smoothly rotate the steering wheel 101, for example, when starting to turn the wheel, thereby improving the steering feeling for the driver.

As with the steering device 100 according to the first embodiment, the correction unit 53 of the torque correction unit 50 may calculate the corrected torque Tc by adding the detected torque Td detected by the torque sensor 109 and the elastic reaction torque Te output from the reaction component calculation unit 352. This makes it possible to reduce the steering load when the steering wheel 101 is turned, and to finely adjust the steering load.

Fourth Embodiment
FIG. 7 is a schematic configuration diagram showing an example of a steering device 400 according to the fourth embodiment.
The steering device 400 according to the fourth embodiment is different from the steering device 200 according to the second embodiment in the target current setting unit 220 of the control device 210. Below, the points that differ from the steering device 200 according to the second embodiment will be described, and the description of the points that are the same as those of the steering device 200 according to the second embodiment will be omitted.

The reaction force component calculation unit 452 of the correction setting unit 422 of the target current setting unit 420 of the control device 410 according to the fourth embodiment has a first elastic component calculation unit 461, a second elastic component calculation unit 462, and a third elastic component calculation unit 463, which are multiple (three in this embodiment) elastic component calculation units that calculate an elastic reaction force component against steering by the driver. The reaction force component calculation unit 452 also has an adder 470 that adds up the elastic reaction force components calculated by the first elastic component calculation unit 461, the second elastic component calculation unit 462, and the third elastic component calculation unit 463.
The first elastic component calculation unit 461 calculates a first elastic correction current Ie1 as an example of an elastic reaction force component based on the following formula (6) when 0≦Δθ≦θ1, and outputs the current to the adder 470. The second elastic component calculation unit 462 calculates a second elastic correction current Ie2 as an example of an elastic reaction force component based on the following formula (7) when θ1<Δθ≦θ2, and outputs the current to the adder 470. The third elastic component calculation unit 463 calculates a third elastic correction current Ie3 as an example of an elastic reaction force component based on the following formula (8) when θ2<Δθ, and outputs the current to the adder 470.
Ie1=Ki1×Δθ...(6)
Ie2=Ki2×Δθ...(7)
Ie3=Ki3×Δθ...(8)
Furthermore, the first elastic component calculation unit 461 outputs Ie1=Ki1×θ1 as an example of a predetermined fixed value when θ1<Δθ, and the second elastic component calculation unit 462 outputs Ie2=Ki2×θ2 as an example of a predetermined fixed value when θ2<Δθ.

Ki1, Ki2, and Ki3 are predetermined proportional constants. Ki1, Ki2, and Ki3 may be the same or different. θ1 and θ2 are predetermined values, and θ1<θ2. θ1 and θ2 can be, for example, 10° and 20°, respectively. The ranges of Δθ using the above formulas (6), (7), and (8) may be set so as not to overlap with each other, or may be set so as to overlap with each other.
The number of elastic component calculation units is not limited to three.

The addition unit 470 outputs the elastic correction current Ie obtained by adding the first elastic correction current Ie1 output by the first elastic component calculation unit 461, the second elastic correction current Ie2 output by the second elastic component calculation unit 462, and the third elastic correction current Ie3 output by the third elastic component calculation unit 463 to the final setting unit 223.
As described above, the reaction force component calculation unit 452 according to the fourth embodiment calculates the elastic correction current Ie as an example of a reaction force component based on the first elastic correction current Ie1, the second elastic correction current Ie2, and the third elastic correction current Ie3 calculated by the first elastic component calculation unit 461, the second elastic component calculation unit 462, and the third elastic component calculation unit 463, and outputs the elastic correction current Ie to the final setting unit 223.

The steering device 400 according to the fourth embodiment configured as described above has the same effects as the steering device 200 according to the second embodiment, and in addition, it is possible to set a finer steering feeling, which results in a further improvement in the steering feeling for the driver.

Furthermore, the first elastic component calculation unit 461 outputs Ie1 = Ki1 x θ1 when θ1 < Δθ, and the second elastic component calculation unit 462 outputs Ie2 = Ki2 x θ2 when θ2 < Δθ. As a result, the larger Δθ is, the larger the value output from the reaction force component calculation unit 452 becomes. Therefore, the steering device 400 can smoothly rotate the steering wheel 101, for example, when starting to turn the wheel, thereby improving the steering feeling for the driver.

As with the steering device 200 according to the second embodiment, the final setting unit 223 may calculate the target current It by adding the basic target current Ib set by the basic setting unit 221 and the elastic correction current Ie set by the correction setting unit 422. This makes it possible to reduce the steering load when the steering wheel 101 is turned, and to finely adjust the steering load.

Fifth embodiment
FIG. 8 is a schematic configuration diagram showing an example of a steering device 500 according to the fifth embodiment.
The steering device 500 according to the fifth embodiment is different from the steering device 100 according to the first embodiment in the torque correction unit 50 of the control device 10. Below, the points that differ from the steering device 100 according to the first embodiment will be described, and the description of the points that are the same as the steering device 100 according to the first embodiment will be omitted.

The torque correction unit 550 of the control device 510 according to the fifth embodiment has a deviation calculation unit 51, a reaction force component calculation unit 552, and a correction unit 53. In addition to the elastic component calculation unit 55, the reaction force component calculation unit 552 has a viscosity component calculation unit 56 that calculates a viscosity reaction force torque Tv against the driver's steering caused by the viscosity, taking into account the viscosity of the transmission mechanism 130. The torque correction unit 550 also has an addition unit 57 that adds the elastic reaction force torque Te calculated by the elastic component calculation unit 55 and the viscosity reaction force torque Tv calculated by the viscosity component calculation unit 56.

The viscosity component calculation unit 56 calculates the viscosity reaction torque Tv based on the following equation (9) using dθs/dt which is the time derivative value of the steering angle θs calculated by the steering angle calculation unit 42.
Tv=Dt×dθs/dt...(9)
Dt is a predetermined proportionality constant.
The viscosity reaction torque Tv is an example of a viscosity reaction component that simulates viscosity based on the steering angle θs. Note that the time differential value of the steering angle θs can be replaced with the deviation Δθ.

The adder 57 calculates the viscoelastic reaction torque Tev (Tev = Te + Tv) by adding the elastic reaction torque Te calculated by the elastic component calculation unit 55 and the viscous reaction torque Tv calculated by the viscous component calculation unit 56, and outputs the viscoelastic reaction torque Tev to the correction unit 53.
As described above, the reaction force component calculation unit 552 according to the fifth embodiment calculates the viscoelastic reaction force torque Tev as an example of a viscoelastic reaction force component based on the elastic reaction force torque Te calculated by the elastic component calculation unit 55 and the viscous reaction force torque Tv calculated by the viscous component calculation unit 56, and outputs the calculated viscoelastic reaction force torque Tev to the correction unit 53.

The correction unit 53 calculates a corrected torque Tc by subtracting the viscoelastic reaction torque Tev calculated by the adder 57 of the reaction force component calculation unit 552 from the detected torque Td detected by the torque sensor 109 (Tc=Td−Tev).
As described above, the torque correction unit 550 calculates the corrected torque Tc. Then, the target current setting unit 20 sets the target current It using the corrected torque Tc.

As described above, the reaction component calculation unit 552 of the control device 510 has a viscosity component calculation unit 56 that calculates the viscosity reaction torque Tv, and an adder unit 57 as an example of a viscoelastic component calculation unit that calculates the viscoelastic reaction torque Tev as an example of a reaction component that simulates viscoelasticity by adding the viscosity reaction torque Tv and the elastic reaction torque Te. The reaction component calculation unit 552 then calculates the reaction component based on the viscoelastic reaction torque Tev. In the control device 510, the reaction component calculation unit 552 uses the viscoelastic reaction torque Tev calculated by the adder unit 57 as the reaction component.

The steering device 500 according to the fifth embodiment configured as described above has a larger hysteresis width than the steering device according to the comparative example, as with the steering device 100 according to the first embodiment, and therefore the steering feeling for the driver can be improved. Furthermore, the steering device 500 according to the fifth embodiment takes into account not only the elasticity of the transmission mechanism 130 but also its viscosity, so that the hysteresis width can be set to a desired size with high precision.

The viscosity component calculation unit 56 may be set not to function in some regions of the deviation Δθ. In other words, the viscosity component calculation unit 56 may output a viscosity reaction torque Tv corresponding to the deviation Δθ based on equation (9) within a predetermined range of the deviation Δθ, and may output 0 outside this range. For example, the viscosity component calculation unit 56 may adjust the viscosity reaction torque Tv calculated based on equation (9) with a gain that is greater than 0 within the predetermined range of the deviation Δθ and is 0 outside this range. This allows for fine-tuned settings of the steering feeling, which results in an improved steering feeling for the driver.

The correction unit 53 of the torque correction unit 50 may calculate the corrected torque Tc by adding the detected torque Td detected by the torque sensor 109 and the viscoelastic reaction torque Tev output by the reaction component calculation unit 552 (Tc = Td + Tev). As a result, when the steering wheel 101 is turned, the absolute value of the target current It becomes larger than in the comparative example, so that the assist force by the electric motor 110 becomes larger and the absolute value of the steering force of the driver becomes smaller. In this way, with this configuration, the load when the steering wheel 101 is turned can be reduced, and the steering feeling can be improved in all steering ranges.

Sixth Embodiment
FIG. 9 is a schematic configuration diagram showing an example of a steering device 600 according to the sixth embodiment.
The steering device 600 according to the sixth embodiment is different from the steering device 200 according to the second embodiment in the target current setting unit 220 of the control device 210. Below, the points that differ from the steering device 200 according to the second embodiment will be described, and the description of the points that are the same as those of the steering device 200 according to the second embodiment will be omitted.

The correction setting unit 622 of the target current setting unit 620 of the control device 610 according to the sixth embodiment has a deviation calculation unit 51 and a reaction force component calculation unit 652 that calculates a reaction force component based on the deviation Δθ calculated by the deviation calculation unit 51.

In addition to the elastic component calculation unit 255, the reaction force component calculation unit 652 has a viscosity component calculation unit 656 that calculates a viscosity correction current Iv for the driver's steering caused by the viscosity, taking into account the viscosity of the transmission mechanism 130. The reaction force component calculation unit 652 also has an adder 657 that adds the elasticity correction current Ie calculated by the elastic component calculation unit 255 and the viscosity correction current Iv calculated by the viscosity component calculation unit 656.
The viscosity component calculation unit 656 calculates the viscosity correction current Iv based on the following equation (10) using the steering angle θs calculated by the steering angle calculation unit 42.
Iv=Di×dθs/dt...(10)
Di is a predetermined proportionality constant.
The viscosity correction current Iv is an example of a viscosity reaction force component that simulates viscosity based on the steering angle θs.

The addition unit 657 calculates the viscoelastic correction current Iev (Iev = Ie + Iv) by adding the elastic correction current Ie calculated by the elastic component calculation unit 255 and the viscosity correction current Iv calculated by the viscosity component calculation unit 656, and outputs the viscoelastic correction current Iev to the final setting unit 223.
As described above, the reaction force component calculation unit 652 according to the sixth embodiment calculates the viscoelastic correction current Iev as an example of a reaction force component based on the elastic correction current Ie calculated by the elastic component calculation unit 255 and the viscosity correction current Iv calculated by the viscosity component calculation unit 656, and outputs it to the final setting unit 223.

The final setting unit 223 calculates the target current It by subtracting the viscoelastic correction current Iev set by the correction setting unit 622 from the basic target current Ib set by the basic setting unit 221 (It = Ib - Iev).

As described above, the reaction component calculation unit 652 of the control device 610 has a viscosity component calculation unit 656 that calculates the viscosity correction current Iv, and an adder unit 657 as an example of a viscoelastic component calculation unit that calculates the viscoelasticity correction current Iev as an example of a reaction component that simulates viscoelasticity by adding the viscosity correction current Iv and the elasticity correction current Ie. The reaction component calculation unit 652 then calculates the reaction component based on the viscoelasticity correction current Iev. In the control device 610, the reaction component calculation unit 652 uses the viscoelasticity correction current Iev calculated by the adder unit 657 as the reaction component.

The steering device 600 according to the sixth embodiment configured as described above has the same effects as the steering device 200 according to the second embodiment, and takes into account not only the elasticity of the transmission mechanism 130 but also its viscosity, making it possible to set the hysteresis width to the desired size with high precision.

The viscosity component calculation unit 656 may be set not to function in some deviation Δθ ranges. In other words, the viscosity component calculation unit 656 may output a viscosity correction current Iv corresponding to the deviation Δθ based on equation (10) in a predetermined range of deviation Δθ, and output 0 outside this range. For example, the viscosity component calculation unit 656 may adjust the viscosity correction current Iv calculated based on equation (10) with a gain that is greater than 0 in the predetermined range of deviation Δθ and is 0 outside this range. This allows for fine-tuned steering feeling settings, resulting in an improved steering feeling for the driver.

Furthermore, similar to the steering device 200 according to the second embodiment, the final setting unit 223 may calculate the target current It by adding the basic target current Ib set by the basic setting unit 221 and the viscoelastic correction current Iev set by the correction setting unit 622. This makes it possible to reduce the steering load when the steering wheel 101 is turned, and to finely adjust the steering load.

Seventh embodiment
FIG. 10 is a schematic configuration diagram showing an example of a steering device 700 according to the seventh embodiment.
The steering device 700 according to the seventh embodiment is different from the steering device 500 according to the fifth embodiment in the torque correction unit 550 of the control device 510. Below, the points that are different from the steering device 500 according to the fifth embodiment will be described, and the description of the points that are the same as the steering device 500 according to the fifth embodiment will be omitted.

The torque correction unit 750 of the control device 710 according to the seventh embodiment has a deviation calculation unit 51, a reaction force component calculation unit 752, and a correction unit 53. The reaction force component calculation unit 752 has a viscosity component calculation unit 56, and the first elastic component calculation unit 361, the second elastic component calculation unit 362, and the third elastic component calculation unit 363 according to the third embodiment. The reaction force component calculation unit 752 also has an addition unit 757 that adds the first elastic reaction force torque Te1 output by the first elastic component calculation unit 361, the second elastic reaction force torque Te2 output by the second elastic component calculation unit 362, the third elastic reaction force torque Te3 output by the third elastic component calculation unit 363, and the viscosity reaction force torque Tv calculated by the viscosity component calculation unit 56. The adder 757 calculates the viscoelastic reaction torque Tev (Tev = Te1 + Te2 + Te3 + Tv) by adding the first elastic reaction torque Te1, the second elastic reaction torque Te2, the third elastic reaction torque Te3, and the viscous reaction torque Tv, and outputs the viscoelastic reaction torque Tev to the correction unit 53.

In this way, the reaction force component calculation unit 752 according to the seventh embodiment calculates the viscoelastic reaction force torque Tev as an example of a reaction force component based on the first elastic reaction force torque Te1, the second elastic reaction force torque Te2, the third elastic reaction force torque Te3, and the viscous reaction force torque Tv, and outputs it to the correction unit 53.

The steering device 700 according to the seventh embodiment configured as described above has the same effects as the steering device 500 according to the fifth embodiment, and in addition, it is possible to set a finer steering feeling, thereby improving the steering feeling.

As with the steering device 100 according to the first embodiment, the correction unit 53 of the torque correction unit 750 may calculate the corrected torque Tc by adding the detected torque Td detected by the torque sensor 109 and the viscoelastic reaction torque Tev output from the reaction component calculation unit 752 (Tc = Td + Tev). This makes it possible to reduce the steering load when the steering wheel 101 is turned, and to finely adjust the steering load.

The torque correction unit 750 also includes a first elastic component calculation unit 361, a second elastic component calculation unit 362, and a third elastic component calculation unit 363 that calculate an elastic reaction force component corresponding to the deviation Δθ within a predetermined range of the deviation Δθ. Similarly, the torque correction unit 750 may include a plurality of viscosity component calculation units 56 (e.g., a first viscosity component calculation unit, a second viscosity component calculation unit, and a third viscosity component calculation unit) that calculate a viscosity reaction force torque Tv corresponding to the deviation Δθ within a predetermined range of the deviation Δθ. Each of the plurality of viscosity component calculation units 56 (e.g., a first viscosity component calculation unit, a second viscosity component calculation unit, and a third viscosity component calculation unit) may output a predetermined fixed value when the deviation Δθ exceeds the predetermined range of the deviation Δθ. This allows for fine-tuned setting of the steering feeling.
Furthermore, the torque correction unit 750 may have a plurality of viscoelastic component calculation units (e.g., a first viscoelastic component calculation unit, a second viscoelastic component calculation unit, and a third viscoelastic component calculation unit) that output a plurality of viscoelastic reaction torques (e.g., a first viscoelastic component calculation unit, a second viscoelastic reaction torque, and a third viscoelastic reaction torque). For example, the first viscoelastic component calculation unit calculates the first viscoelastic reaction torque by adding the first elastic reaction torque Te1 calculated by the first elastic component calculation unit 361 and the first viscoelastic reaction torque calculated by the first viscoelastic component calculation unit. The adder 757 may calculate the viscoelastic reaction torque Tev by adding the plurality of viscoelastic reaction torques calculated by the plurality of viscoelastic component calculation units, and output the viscoelastic reaction torque Tev to the correction unit 53. Alternatively, the torque correcting unit 750 may output the multiple viscoelastic reaction torques calculated by the multiple viscoelastic component calculating units to the correcting unit 53 without adding them up in the adding unit 757 .

Eighth embodiment
FIG. 11 is a schematic configuration diagram showing an example of a steering device 800 according to the eighth embodiment.
The steering device 800 according to the eighth embodiment is different from the steering device 600 according to the sixth embodiment in a target current setting unit 620 of a control device 610. Below, the points that differ from the steering device 600 according to the sixth embodiment will be described, and a description of the points that are the same as those of the steering device 600 according to the sixth embodiment will be omitted.

The correction setting unit 822 of the target current setting unit 820 of the control device 810 relating to the eighth embodiment has a deviation calculation unit 51 and a reaction force component calculation unit 852 that calculates a reaction force component based on the deviation Δθ calculated by the deviation calculation unit 51.
The reaction force component calculation unit 852 has a viscosity component calculation unit 656, and a first elastic component calculation unit 461, a second elastic component calculation unit 462, and a third elastic component calculation unit 463 according to the fourth embodiment. The reaction force component calculation unit 852 also has an adder 857 that adds the first elasticity correction current Ie1 output by the first elasticity component calculation unit 461, the second elasticity correction current Ie2 output by the second elasticity component calculation unit 462, the third elasticity correction current Ie3 output by the third elasticity component calculation unit 463, and the viscosity correction current Iv calculated by the viscosity component calculation unit 656. The addition unit 857 calculates the viscoelastic correction current Iev (Iev = Ie1 + Ie2 + Ie3 + Iv) by adding the first elastic correction current Ie1, the second elastic correction current Ie2, the third elastic correction current Ie3, and the viscosity correction current Iv, and outputs the viscoelastic correction current Iev to the final setting unit 223.

In this way, the reaction force component calculation unit 852 according to the eighth embodiment calculates the viscoelastic correction current Iev as an example of a reaction force component based on the first elastic correction current Ie1, the second elastic correction current Ie2, the third elastic correction current Ie3, and the viscoelastic correction current Iev, and outputs it to the final setting unit 223.

The steering device 800 according to the eighth embodiment configured as described above has the same effects as the steering device 600 according to the sixth embodiment, and in addition, it is possible to set a finer steering feeling, which results in a further improvement in the steering feeling for the driver.

As with the steering device 200 according to the second embodiment, the final setting unit 223 may calculate the target current It by adding the basic target current Ib set by the basic setting unit 221 and the viscoelastic correction current Iev set by the correction setting unit 822. This makes it possible to reduce the steering load when the steering wheel 101 is turned, and to finely adjust the steering load.

The correction setting unit 822 also has a first elastic component calculation unit 461, a second elastic component calculation unit 462, and a third elastic component calculation unit 463 that calculate an elastic reaction force component corresponding to the deviation Δθ within a predetermined range of the deviation Δθ. Similarly, the correction setting unit 822 may have a plurality of viscosity component calculation units 656 (e.g., a first viscosity component calculation unit, a second viscosity component calculation unit, and a third viscosity component calculation unit) that calculate a viscosity correction current Iv corresponding to the deviation Δθ within a predetermined range of the deviation Δθ. Each of the plurality of viscosity component calculation units 656 (e.g., a first viscosity component calculation unit, a second viscosity component calculation unit, and a third viscosity component calculation unit) may output a predetermined fixed value when the deviation Δθ exceeds the predetermined range of the deviation Δθ. This makes it possible to set a fine steering feeling.
The correction setting unit 822 may also have a plurality of viscoelastic component calculation units (e.g., a first viscoelastic component calculation unit, a second viscoelastic component calculation unit, and a third viscoelastic component calculation unit) that output a plurality of viscoelastic correction currents (e.g., a first viscoelastic component calculation unit, a second viscoelastic component calculation unit, and a third viscoelastic correction current). For example, the first viscoelastic component calculation unit calculates the first viscoelastic correction current by adding the first elastic correction current Ie1 calculated by the first elastic component calculation unit 461 and the first viscosity correction current calculated by the first viscosity component calculation unit. The adder 857 may then calculate the viscoelastic correction current Iev by adding the plurality of viscoelastic correction currents calculated by the plurality of viscoelastic component calculation units, and output the viscoelastic correction current Iev to the final setting unit 223. Alternatively, the correction setting unit 822 may output the plurality of viscoelastic correction currents calculated by the plurality of viscoelastic component calculation units to the final setting unit 223 without adding them by the adder 857.

Ninth embodiment
FIG. 12 is a schematic configuration diagram showing an example of a steering device 900 according to the ninth embodiment.
The steering device 900 according to the ninth embodiment is different from the steering device 100 according to the first embodiment in the torque correction unit 50 of the control device 10. Below, the points that differ from the steering device 100 according to the first embodiment will be described, and the description of the points that are the same as the steering device 100 according to the first embodiment will be omitted.

The torque correction unit 950 of the control device 910 according to the ninth embodiment has a deviation calculation unit 51 , a reaction force component calculation unit 952 , and a correction unit 53 .
The reaction force component calculation unit 952 has an elastic component calculation unit 55 and a vehicle state correction unit 80 that corrects the elastic reaction force torque Te calculated by the elastic component calculation unit 55 in accordance with the state of the vehicle.

The vehicle state correction unit 80 can, for example, correct the elastic reaction torque Te according to the vehicle speed Vc. For example, the vehicle state correction unit 80 multiplies the elastic reaction torque Te by a coefficient that decreases as the vehicle speed Vc increases so that the absolute value of the elastic reaction torque Te decreases as the vehicle speed Vc increases, and outputs the correction value Tec obtained by the multiplication to the correction unit 53 as the output value of the reaction component calculation unit 952.

Further, the vehicle state correcting unit 80 may, for example, correct the elastic reaction torque Te in accordance with the ambient temperature of the vehicle. For example, the vehicle state correcting unit 80 may multiply the elastic reaction torque Te by a coefficient that decreases as the ambient temperature decreases so that the absolute value of the elastic reaction torque Te decreases as the ambient temperature decreases, and may output the correction value Tec obtained by the multiplication to the correcting unit 53 as the output value of the reaction component calculating unit 952.
Furthermore, the vehicle state correcting unit 80 may correct the elastic reaction torque Te in accordance with the detected torque Td.

As described above, the control device 910 has the elastic component calculation unit 55 that calculates the elastic reaction torque Te simulating elasticity based on the steering angle θs, and is equipped with a reaction component calculation unit 952 that calculates a correction value Tec as an example of a reaction component based on the elastic reaction torque Te. In the control device 910, the reaction component calculation unit 952 multiplies the elastic reaction torque Te calculated by the elastic component calculation unit 55 by a predetermined coefficient to obtain a correction value Tec (Tec = Te x coefficient), which is set as the reaction component.
In this way, by correcting the elastic reaction torque Te in accordance with the state of the vehicle, it becomes possible to set a finely tuned steering feeling, and as a result, the steering feeling for the driver can be improved.

In addition, the vehicle state correction unit 80 may be provided in the reaction component calculation unit 352, 552, 752 according to the third, fifth, or seventh embodiment, and may correct the reaction components (elastic reaction torque Te, viscoelastic reaction torque Tev) output from the reaction component calculation unit 352, 552, 752.
In addition, the vehicle state correction unit 80 may be provided in the reaction force component calculation units 252, 452, 652, 852 relating to the second, fourth, sixth and eighth embodiments, and may correct the reaction force components (elastic correction current Ie, viscoelastic correction current Iev) output from the reaction force component calculation units 252, 452, 652, 852.

Tenth embodiment
FIG. 13 is a diagram showing an example of a schematic configuration of a steer-by-wire system 1000 according to the tenth embodiment.
The steer-by-wire system 1000 according to the tenth embodiment differs from the steering device 100 according to the first embodiment in that the steering wheel 101 and the front wheels 150 are not connected by a steering shaft 102 or the like but are mechanically separated. Below, the points that differ from the steering device 100 according to the first embodiment will be described, and a description of the points that are the same as those of the steering device 100 according to the first embodiment will be omitted.

The steer-by-wire system 1000 includes a reaction motor 1001, which is an electric motor that applies a steering reaction force to the steering of the steering wheel 101, and a gear 1002 that is attached to the steering shaft 102 and meshes with a gear attached to the output shaft of the reaction motor 1001. The steer-by-wire system 1000 also includes a fixing unit 1003 that fixes the steering shaft 102 at an arbitrary rotation angle. The steer-by-wire system 1000 also includes a steering detection device 1004 that detects the steering angle θs and the steering torque. The steering detection device 1004 detects the steering angle θs based on the rotation angle of the steering shaft 102, and detects the steering torque based on the amount of twist of the steering shaft 102. The steering torque detected by the steering detection device 1004 is the detected torque Td.

The steer-by-wire system 1000 has a control device 1010 that controls the driving of the electric motor 110 and also controls the driving of the reaction motor 1001 .
FIG. 14 is a schematic diagram showing an example of a reaction motor control unit 1011 that controls the driving of the reaction motor 1001 in the control device 1010.
The reaction motor control unit 1011 includes a target current setting unit 20 that sets a target current It required to be supplied to the reaction motor 1001, and a control unit 30 that performs feedback control and the like based on the target current It calculated by the target current setting unit 20. The reaction motor control unit 1011 also includes a torque correction unit 1050 that corrects the detected torque Td detected by the steering detection device 1004 to calculate a corrected torque Tc.

The torque correction unit 1050 has a deviation calculation unit 51 that calculates the deviation Δθ of the steering angle θs detected by the steering detection device 1004, and a reaction force component calculation unit 52 that calculates a reaction force component against the steering by the driver based on the deviation Δθ calculated by the deviation calculation unit 51. The torque correction unit 1050 also has a correction unit 53 that corrects the detected torque Td using the reaction force component calculated by the reaction force component calculation unit 52.

The steer-by-wire system 1000 described above provides the same effects as those provided by the steering device 100 according to the first embodiment, and therefore can improve the steering feeling.
As described above, the reaction motor control unit 1011 has the functions of the control device 10 according to the first embodiment. Similarly, the reaction motor control unit 1011 may have the functions of any of the control devices according to the second to ninth embodiments (e.g., the control device 210).

In the target current setting unit 220 of the steering device 200 according to the second embodiment, the correction setting unit 222 sets a correction current that corrects the basic target current Ib, but is not limited to this mode. The correction current corrected by the correction setting unit 222 may be the target current It. For example, the target current setting unit 220 may not include the basic setting unit 221 and the final setting unit 223. Alternatively, in the target current setting unit 220, the basic target current Ib set by the basic setting unit 221 may be set to 0. Similarly, in the target current setting units 420, 620, and 820 according to the fourth, sixth, and eighth embodiments, the correction current corrected by the correction setting units 422, 622, and 822 may be the target current It. Alternatively, in the target current setting units 420, 620, and 820, the basic target current Ib set by the basic setting unit 221 may be set to 0.

The control devices 10, 310, 510, and 710 according to the first, third, fifth, and seventh embodiments are configured to correct the detected torque Td, which is an example of the value of the steering input signal of the driver, based on the reaction force component, and the control devices 210, 410, 610, and 810 according to the second, fourth, sixth, and eighth embodiments are configured to correct the basic target current Ib based on the reaction force component. These modes of correcting the detected torque Td and the modes of correcting the basic target current Ib may be appropriately combined. In other words, the basic target current Ib may be set using the corrected torque Tc obtained by correcting the detected torque Td based on the reaction force component, and the set basic target current Ib may be corrected based on the reaction force component to calculate the target current It.

10,210,310,410,510,610,710,810,910,1010...control device, 20...target current setting unit, 50...torque correction unit, 52,252,352,452,552,652,752,852,952...reaction force component calculation unit, 53...correction unit, 55,255...elastic component calculation unit, 56,656...viscosity component calculation unit, 57,370,470,657,757,857...addition unit, 80...vehicle state correction unit, 100,200,300,400,500,600,700,800,900...steering device, 130...transmission mechanism, 223...final setting unit, 1000...steer-by-wire system

Claims (10)

a target control amount calculation unit that calculates a target control amount based on a value of a steering input signal from a driver;
a deviation calculation unit that calculates a deviation by subtracting a previously acquired value of the steering angle from a currently acquired value of the steering angle, the steering angle being periodically acquired from a steering angle calculation unit that calculates a steering angle ;
a reaction force component calculation unit including an elastic component calculation unit that calculates an elastic reaction force component simulating elasticity based on the deviation, and that calculates a reaction force component based on the elastic reaction force component;
a correction unit that corrects at least one of the value of the steering input signal or the target control amount based on the reaction force component;
A control device comprising: The reaction force component calculation unit has a plurality of the elastic component calculation units.
The control device according to claim 1 . the reaction force component calculation unit further includes an adder that adds up values output from a plurality of the elastic component calculation units,
3. The control device according to claim 2, wherein each of the elastic component calculation units calculates the elastic reaction force component corresponding to the deviation within a predetermined deviation range that is set individually, and outputs a predetermined fixed value when the deviation exceeds the range. The reaction force component calculation unit further includes a viscosity component calculation unit that calculates a viscosity reaction force component that simulates viscosity based on a steering angle, and a viscoelastic component calculation unit that calculates a viscoelastic reaction force component that is a reaction force component that simulates viscoelasticity based on the viscosity reaction force component and the elastic reaction force component, and calculates the reaction force component based on the viscoelastic reaction force component.
The control device according to any one of claims 1 to 3. The control device according to claim 4 , wherein the viscosity component calculation unit outputs the viscosity reaction force component according to the deviation within a predetermined range of the deviation that is set, and outputs 0 outside the range. A vehicle state correction unit corrects the reaction force component in accordance with a vehicle speed, an ambient temperature, or a steering torque.
A control device according to any one of claims 1 to 5. the reaction force component calculation unit calculates a torque value as the reaction force component,
The correction unit adds or subtracts the reaction force component to or from a value of the steering input signal calculated as the steering torque.
A control device according to any one of claims 1 to 6. the reaction force component calculation unit calculates a current value as the reaction force component,
The correction unit adds or subtracts the reaction force component to or from the target control amount calculated as a current value.
A control device according to any one of claims 1 to 6. A control device according to any one of claims 1 to 8,
Electric power steering device. A control device according to any one of claims 1 to 8,
Steer-by-wire system.