JP3830750B2 - Control device for electric power steering device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for an electric power steering device that applies assist force by a motor to a steering system of an automobile or a vehicle.
[0002]
[Prior art]
  Figure12These show the outline of the electric power steering apparatus used for the conventional motor vehicle etc., and its control apparatus 158. FIG.
[0003]
A steering shaft 142 connected to the steering wheel 141 is provided with a torsion bar 143. A torque sensor 144 is attached to the torsion bar 143. When the steering shaft 142 rotates and a force is applied to the torsion bar 143, the torsion bar 143 is twisted according to the applied force, and the torque sensor 144 detects the twist.
[0004]
In the following description, the steering wheel may be referred to as a steering wheel (the same applies to conventional techniques and embodiments).
A reduction gear 145 is fixed to the steering shaft 142. A gear 147 attached to the rotating shaft of the motor 146 is meshed with the speed reducer 145. Further, a pinion shaft 148 is fixed to the speed reducer 145. A pinion 149 is fixed to the tip of the pinion shaft 148, and the pinion 149 meshes with the rack 151. The rack 151 and the pinion 149 constitute a rack and pinion mechanism 150.
[0005]
Tie rods 152 are fixed to both ends of the rack 151. A knuckle 153 is rotatably connected to both ends of the tie rod 152. A front wheel 154 is fixed to the knuckle 153. The knuckle 153 is rotatably connected to the cross member 155.
[0006]
Therefore, when the motor 146 rotates, the number of rotations is reduced by the speed reducer 145 and transmitted to the pinion shaft 148 and transmitted to the rack and pinion mechanism 150. Then, the knuckle 153 connected to the tie rod 152 moves rightward or leftward depending on the rotation direction of the motor 146. A vehicle speed sensor 156 is provided on the front wheel 154.
[0007]
The rotational speed and rotational direction of the motor 146 are determined by positive and negative assist currents supplied from the motor driving device 157. The assist current that the motor driving device 157 supplies to the motor 146 is calculated by the control device 158 that controls the motor driving device 157. The control device 158 includes a CPU 159, a ROM 160, a RAM 161, and the like, calculates the steering torque Th of the steering wheel 141 from the detection signal from the torque sensor 144, and calculates the vehicle speed from the detection signal from the vehicle speed sensor 156. V is calculated.
[0008]
Then, the control device 158 calculates an assist current (assist current command value) based on the calculated steering torque Th and the vehicle speed V. This calculation is obtained from an assist map stored in advance in the ROM 160 in the control device 158. Then, the control device 158 controls the current of the motor 146 that generates assist torque so as to become the assist current (assist current command value).
[0009]
  Here, an outline of the control of the CPU 159 will be described.
  Figure14These are the functional block diagrams of CPU159 of the conventional control apparatus 158, and show the function performed by the program inside CPU159, and do not mean an actual hardware configuration.
[0010]
  The steering torque detected by the torque sensor 144 is phase-compensated by the phase compensator 170 in order to improve system stability, and the phase-compensated steering torque Th is input to the current command value calculation unit 171. The vehicle speed V detected by the vehicle speed sensor 156 is also input to the current command value calculation unit 171. The current command value calculation unit 171 calculates an assist current command value I corresponding to the vehicle speed V and the steering torque Th based on an assist map stored in advance in the ROM 160 (FIG.13reference).
[0011]
The assist current command value I is added by an adder 172 to a handle return current Ih * and a damper current Id *, which will be described later, and supplied to the current control unit 173. In the current control unit 173, based on a signal corresponding to the difference between the output of the adder 172 and the actual motor current (motor drive current) Im detected by the motor drive current sensor 176, the PI control value and the PID control value And the control value is output to the PWM calculation unit 174. The PWM calculation unit 174 performs PWM calculation according to the control value, and supplies the calculation result to the motor driving device 157.
[0012]
As a result, by controlling the driving of the motor 146 via the motor driving device 157, an appropriate assist force by the motor 146 can be obtained.
On the other hand, the motor angular velocity estimator 175 has the following motor voltage equation based on the motor current Im of the motor 146 detected by the motor drive current sensor 176 and the motor terminal voltage Vm detected by the terminal voltage detection circuit 177 of the motor 146. To estimate the motor angular velocity ω.
[0013]
ω = {Vm− (R + LS) Im} / Ke
R is a motor resistance, L is a motor inductance, Ke is a motor back electromotive force constant, and S is a differential operator.
[0014]
The steering angular velocity estimator 178 estimates the steering angular velocity Q (= ω / G) by dividing the reduction ratio G of the reducer 145 based on the motor angular velocity ω estimated by the motor angular velocity estimator 175. The steering angular velocity estimated by the steering angular velocity estimator 178 is input to the steering wheel return controller 180 and the damper controller 190. The vehicle speed V detected by the vehicle speed sensor 156 is input to the handle return controller 180 and the damper controller 190.
[0015]
Here, an outline of the handle return controller 180 will be described.
The steering wheel return controller 180 outputs a steering wheel return current Ih * corresponding to the vehicle speed V and the steering angular velocity Q in the steering wheel returning state in order to improve the steering wheel return characteristic at the time of low speed traveling. Assist in the direction that) returns.
[0016]
  Figure15Shows a functional block diagram for performing a handle return calculation in the handle return controller 180.
  As shown in the figure, the handle return controller 180 includes a handle return current calculation unit 181, a handle return compensation vehicle speed gain calculation unit 182, a handle return determination unit 183, and a multiplier 184. The steering wheel return current calculation unit 181 includes a steering wheel return compensation map. When the steering angular velocity Q is input, the steering wheel return current Ih is read with reference to the steering wheel return compensation map and input to the multiplier 184. This handle return current Ih is set so as to assist in the direction of rotation of the handle.
[0017]
When the vehicle speed V is input, the steering wheel return compensation vehicle speed gain calculation unit 182 reads the vehicle speed gain Kh with reference to the steering wheel return compensation gain map and supplies the vehicle speed gain Kh to the multiplier 184. The gain Kh is set so that the steering wheel return current is set to 0 in medium and high speed traveling, and the steering wheel return control is effective only in low speed traveling.
[0018]
The steering wheel return determination unit 183 includes a steering wheel return determination map. When the steering torque Th is input, when the steering torque Th is near 0 based on the map, the steering wheel return determination unit 183 outputs “1” as the gain B. As shown in steering torque | Th |> X (X (> 0) is a threshold value), when the value becomes equal to or larger than a certain value X, “0” is output as a gain B to the multiplier 184. That is, when the steering torque Th is within the threshold value, it is determined that the steering wheel is returned. The multiplier 184 multiplies Ih, Kh, and G input from the steering wheel return current calculation unit 181, steering wheel return compensation vehicle speed gain calculation unit 182, and steering wheel return determination unit 183, and adds the steering wheel return current Ih * to the adder 172. Output to.
[0019]
Accordingly, when the steering wheel return determination unit 183 determines that the steering wheel has been returned when the vehicle speed is low, the steering wheel return current Ih * is added to the assist current and Handle return characteristics are improved.
[0020]
Next, the damper controller 190 will be described.
The damper controller 190 outputs a damper current Id * corresponding to the vehicle speed V and the steering angular velocity Q in order to improve the yaw convergence of the vehicle during medium-high speed traveling, and in a direction opposite to the direction in which the steering wheel rotates. This is for applying a damper current Id * to apply a brake.
[0021]
  Figure16FIG. 4 shows a functional block diagram for performing a damper current calculation in the damper controller 190. As shown in the figure, the damper controller 190 includes a damper current calculation unit 191, a damper compensation vehicle speed gain calculation unit 192, and a multiplier 193. The damper current calculation unit 191 includes a damper current map. When the steering angular velocity Q is input, the damper current calculation unit 191 reads the damper current Id with reference to the damper current map and inputs it to the multiplier 193. Note that the damper current Id is set in a direction to decelerate the steering angular velocity, and has a polarity opposite to that of the steering wheel return control.
[0022]
When the vehicle speed V is input, the damper compensation vehicle speed gain calculation unit 192 reads the damper gain Kd with reference to the damper gain map and supplies the damper gain Kd to the multiplier 193. The damper gain Kd is set so that the damper current becomes zero in low-speed traveling and the damper control is effective in medium and high speeds.
[0023]
The multiplier 193 multiplies Id and Kd input from the damper current calculation unit 191 and the damper compensation vehicle speed gain calculation unit 192, and outputs the damper current Id * to the adder 172.
[0024]
Therefore, when the vehicle speed is medium to high, the damper controller 190 adds the damper current Id * to the assist current command value I, thereby improving the damper characteristics at medium and high speeds.
[0025]
[Problems to be solved by the invention]
By the way, as described above, the maps of the steering wheel return controller 180 and the damper controller 190 are stored in advance in the ROM 160 and have values adapted to a certain reference road surface. It is usually set to a value that is optimal for dry asphalt surfaces.
[0026]
However, for example, when the vehicle travels on a road surface with a low road reaction force such as a low μ road, the output of the handle return current Ih * at the handle return controller 180 during low speed traveling is low, the handle stops halfway, and the residual angle (neutral) There has been a problem that the position (angle of the steering wheel when the vehicle goes straight) becomes larger as a reference. In addition, when the vehicle travels on a road surface with a low road reaction force such as a low μ road during medium / high speed traveling, there is a problem that the output of the damper current Id * in the damper controller 190 becomes excessive and the damper becomes too effective.
[0027]
  There is also a handle return controller 200 that calculates a handle return current with respect to the vehicle speed V and the steering angle as a method for improving the handle return characteristic during low-speed traveling.
  Figure17These are functional block diagrams of the handle return controller 200. FIG.
[0028]
The steering wheel return controller 200 includes a steering wheel return current calculation unit 201, a steering wheel return compensation vehicle speed gain calculation unit 182, and a multiplier 184.
The steering wheel return current calculation unit 201 includes a steering wheel return compensation map. When the steering wheel return current Ih is input from a steering angle sensor (not shown) that detects the steering angle θh of the steering wheel 141, the steering wheel return current Ih is referred to. Read and input to multiplier 184. The multiplier 184 multiplies Ih and Kh input from the steering wheel return current calculation unit 201 and the steering wheel return compensation vehicle speed gain calculation unit 182 to calculate a steering wheel return current (temporary steering wheel return current) Ih *. Then, the CPU 159 determines the steering state, determines whether or not the steering angle θh and the polarity of the steering angular velocity are opposite, and if they are opposite, determines that the steering wheel return state is present, and sets the provisional steering wheel return current Ih *. The handle return current Ih * is output to the adder 172. Otherwise, the handle return current Ih * is output as 0 to the adder 172.
[0029]
However, even in the steering wheel return controller 200, when the road surface changes, there is a problem that the steering angular velocity is affected by the road surface because the speed at which the steering wheel returns is too fast or too slow.
[0030]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an electric power steering apparatus capable of obtaining a stable handle convergence from low speed to high speed even when the road surface reaction force changes. It is to provide a control device.
[0031]
[Means for Solving the Problems]
  In order to solve the above problems, the invention according to claim 1 is directed to a target steering angle setting means for setting a target steering angle for returning the steering wheel to a neutral position based on the steering angle and the vehicle speed, and the target steering angle. Target steering angular speed setting means for setting the target steering angular speed based on the deviation of the steering angle and the vehicle speed, and target convergence current setting means for setting the target convergence current based on the deviation of the target steering angular speed and the steering angular speed. ,
  The target convergence current setting means, when setting the target convergence current based on the deviation of the target steering angular velocity and the steering angular velocity, proportional control, integral control,as well asDifferential systemTo meSet target convergence current based onIn the proportional control, integral control, and differential control performed by the target convergence current setting means, the target convergence current is set by performing correction according to the vehicle speed.The gist of the control device for the electric power steering apparatus is characterized by the following.
[0032]
The gist of a second aspect of the invention is the control device for the electric power steering apparatus according to the first aspect, wherein the target steering angular velocity setting means sets the target steering angular velocity by performing correction according to the vehicle speed.
[0033]
  The invention of claim 3 is the invention according to claim 1 or claim 2,Hand release determining means for determining whether to release the handle based on the steering torque or determining whether to steer or hold the steering, the release determination means effectively outputs the target convergence current output of the target convergence current setting means based on the determination result. To suppress or suppressThe gist of the control device of the dynamic power steering device is as follows.
[0034]
  Invention of Claim 4 in any one of Claim 1 thru | or 3,When the hand release determination means determines steering / holding and suppresses the output of the target convergence current setting means, the hand release determination means is obtained by integral control of the target convergence current setting means. The power to reset the integral termThe gist of the control device of the dynamic power steering device is as follows.
[0035]
  The invention according to claim 5 is the invention according to any one of claims 1 to 4.The target steering angle setting means sets the target steering angle for returning the steering wheel to the neutral position based on the steering angle and the vehicle speed phase-compensated by the phase compensation means. ElectricThe gist of the control device of the dynamic power steering device is as follows.
[0039]
(Function)
According to the first aspect of the present invention, the target steering angle setting means sets the target steering angle for returning the steering wheel to the neutral position based on the steering angle and the vehicle speed. The target steering angular velocity setting means sets the target steering angular velocity based on the deviation between the target steering angle and the steering angle and the vehicle speed. The target convergence current setting means sets the target convergence current based on the deviation between the target steering angular velocity and the steering angular velocity.
[0040]
  Further, the target convergence current setting means sets proportional control, integral control, when setting the target convergence current based on the deviation between the target steering angular velocity and the steering angular velocity.as well asDifferential systemTo meBased on the target convergence current.In the proportional control, integral control, and differential control performed by the target convergence current setting means, the target convergence current is set by performing correction according to the vehicle speed.
[0041]
  According to the invention of claim 2, the target steering angular velocity setting means sets the target steering angular velocity by performing correction according to the vehicle speed..
[0043]
  Claim3According to this invention, the hand release determining means performs the hand release determination or the steering / holding determination based on the steering torque. Further, the hand release determination means validates or suppresses the output of the target convergence current of the target convergence current setting means based on the determination result.
[0044]
  Claim4According to the invention, when the hand release determining means determines steering / holding and suppresses the output of the target convergence current of the target convergence current setting means, the hand release determination means includes the integration of the target convergence current setting means. Resets the integral term obtained by the control.
[0045]
  Claim5According to the invention, the phase compensation means compensates the phase of the steering angle. The target steering angle setting means sets a target steering angle for returning the steering wheel to the neutral position based on the steering angle phase-compensated by the phase compensation means and the vehicle speed.
[0046]
DETAILED DESCRIPTION OF THE INVENTION
  (First embodiment)
  1 to FIG. 1 show an embodiment in which the present invention is embodied in a control device 20 for an electric power steering device mounted on an automobile.11It explains according to.
[0047]
FIG. 1 schematically shows an electric power steering device and its control device 20.
A torsion bar 3 is provided on a steering shaft 2 as a steering shaft connected to the steering wheel 1. A torque sensor 4 is attached to the torsion bar 3. When the steering shaft 2 rotates and a force is applied to the torsion bar 3, the torsion bar 3 is twisted according to the applied force, and the torque sensor 4 detects the twist, that is, the steering torque Th applied to the steering wheel 1. Yes.
[0048]
A reduction gear 5 is fixed to the steering shaft 2. A gear 7 attached to a rotary shaft of an electric motor (hereinafter referred to as a motor) 6 is engaged with the speed reducer 5. Further, a pinion shaft 8 is fixed to the speed reducer 5. A pinion 9 is fixed to the tip of the pinion shaft 8, and the pinion 9 meshes with the rack 10. The rack 10 and the pinion 9 constitute a rack and pinion mechanism 11.
[0049]
A tie rod 12 is fixed to both ends of the rack 10, and a knuckle 13 is rotatably connected to the tip of the tie rod 12. A front wheel 14 as a tire is fixed to the knuckle 13. One end of the knuckle 13 is rotatably connected to the cross member 15.
[0050]
Therefore, when the motor 6 rotates, the number of rotations is reduced by the speed reducer 5 and transmitted to the pinion shaft 8, and is transmitted to the rack 10 via the rack and pinion mechanism 11. The rack 10 can change the traveling direction of the vehicle by changing the direction of the front wheel 14 provided on the knuckle 13 via the tie rod 12.
[0051]
A vehicle speed sensor 16 is provided on the front wheel 14. A steering angle sensor 17 for detecting the steering angle θ of the steering shaft 2 is mounted on the steering shaft 2.
[0052]
Next, an electrical configuration of the control device 20 of the electric power steering device will be described. The torque sensor 4 outputs a detection signal indicating the steering torque Th of the steering wheel 1 to the control device 20. The vehicle speed sensor 16 outputs a detection signal indicating the vehicle speed V at that time to the control device 20 relative to the rotational speed of the front wheels 14.
[0053]
The steering angle sensor 17 outputs a detection signal indicating the steering angle θ of the steering shaft 2 to the control device 20. Further, as shown in FIG. 2, a motor drive current sensor 18 for detecting a drive current (motor current Im, corresponding to a motor current value) flowing through the motor 6 is electrically connected to the control device 20 to drive the motor. A signal indicating the motor current Im from the current sensor 18 is supplied. The terminal voltage detection circuit 19 outputs the motor terminal voltage Vm of the motor 6 to the control device 20.
[0054]
The control device 20 includes a central processing unit (CPU) 21 as a control means, a read only memory (ROM) 22 and a read and write only memory (RAM) 23 for temporarily storing data. The ROM 22 stores various control programs such as assist control and convergence control executed by the CPU 21. The RAM 23 temporarily stores calculation processing results and the like when the CPU 21 performs calculation processing.
[0055]
The CPU 21 receives detection signals from the various sensors, calculates a motor command current value based on the detection signals in the processing of various control programs such as assist control and convergence control, and outputs them to the motor driving device 24. Then, the motor 6 is driven and controlled via the motor driving device 24.
[0056]
In the present embodiment, the CPU 21 corresponds to target steering angle setting means, target steering angular speed setting means, target convergence current setting means, and hand release determination means.
(Operation of the first embodiment)
In the following description of the internal functions of the CPU 21, various parameters such as “vehicle speed V”, “steering torque Th”, and “steering angle θ” are used as meanings of their corresponding signals for convenience of explanation.
[0057]
FIG. 2 is a functional block diagram of the CPU 21. In this embodiment, functions executed by programs in the CPU 21 are shown. For example, the phase compensator 30 is not an independent hardware, but represents a phase compensation function executed in the CPU 21. Similarly, FIGS. 3 to 5, FIG. 9, and FIG. 10 are functional block diagrams showing the processing functions executed by the CPU 21 by the program, and do not mean an actual hardware configuration.
[0058]
Hereinafter, functions and operations of the CPU 21 will be described.
(Vehicle speed sensitive assist control)
The steering torque Th input from the torque sensor 4 is phase-compensated by the phase compensator 30 in order to increase the stability of the steering system, and is input to the current command value calculation unit 31. The vehicle speed V detected by the vehicle speed sensor 16 is also input to the current command value calculation unit 31. The current command value calculation unit 31 determines a vehicle speed sensitive assist command value (corresponding to an assist current command value) I that is a control target value of the current supplied to the motor 6 based on the input steering torque Th and the vehicle speed V. To do.
[0059]
As shown in FIG. 3, the current command value calculation unit 31 of the CPU 21 inputs the steering torque Th and the vehicle speed V, and calculates the assist current command value I based on these parameters.
[0060]
Specifically, as shown in the figure, the steering torque Th is supplied to the high-speed assist map 101, and the high-speed assist current (high-speed assist amount) Id1 is read, or is supplied to the low-speed assist map 102 and the low-speed assist current ( Low speed assist amount) Id2 is read out. The read high speed assist current is supplied to the multiplier 104, and the low speed assist current is supplied to the multiplier 105.
[0061]
On the other hand, the vehicle speed V is supplied to the assist vehicle speed gain map 103, and the assist vehicle speed gain k 1 is read from the assist vehicle speed gain map 103 based on the vehicle speed V and supplied to the multiplier 105 and the adder 107. The assist vehicle speed gain k1 supplied to the adder 107 is inverted in sign and added with “1” and supplied to the multiplier 104 as (1−k1).
[0062]
The multiplier 104 multiplies the supplied (1-k1) by the high-speed assist current Id1, and supplies the output value to the adder 106. The multiplier 105 multiplies the supplied assist vehicle speed gain k1 by the low speed assist current Id2, and then supplies the output value to the adder 106. The adder 106 outputs an assist current command value I obtained by adding the values obtained by multiplication by the multipliers 104 and 105 to the adder 39 shown in FIG.
[0063]
The adder 39 adds the assist current command value I and an output value from another unit (described later), and outputs the result to the PI control unit 40. The PI control unit 40 calculates a current value by a known PI control based on a signal (corresponding to an assist current control value) corresponding to a difference from the actual motor current Im, and outputs this value to the PWM calculation unit 38. . The PWM calculation unit 38 performs PWM calculation based on the value obtained by the PI control, and supplies the calculation result to the motor driving device 24.
[0064]
As a result, by driving and controlling the motor 6 via the motor driving device 24, an appropriate assist force by the motor 6 can be obtained according to the detected steering torque Th and the vehicle speed V.
[0065]
(Steering angular velocity Q)
Next, how to obtain the steering angular velocity Q input to the convergence control unit 81 will be described. When a voltage is applied between the terminals of the motor 6, the motor 6 rotates. When the motor 6 rotates, a counter electromotive force is generated in proportion to the number of rotations, and is added to the motor terminal voltage Vm. The relationship between the motor terminal voltage Vm and the back electromotive force of the motor 6 can be expressed by the following equation.
[0066]
Vm = (Ls + R) · Im + Ke · ω (1)
Here, Vm: voltage between motor terminals, L: inductance of motor 6, s: Laplace operator, R: resistance between terminals of motor 6, Im: motor current, Ke: back electromotive force constant of motor 6, ω: motor Angular velocity.
[0067]
Therefore, when the above equation (1) is solved by ω (motor angular velocity), the following equation (2) is obtained. ω = {Vm− (Ls + R) · Im} / Ke
Therefore, the first calculation unit 50 shown in FIG. 4 multiplies the motor current Im input from the motor drive current sensor 18 by (Ls + R) and outputs the result to the subtractor 51. The subtractor 51 subtracts the value calculated by the first calculation unit 50 from the motor terminal voltage Vm input from the terminal voltage detection circuit 19 and outputs the value to the second calculation unit 52.
[0068]
The second calculation unit 52 calculates the motor angular velocity ω by dividing the value input from the subtractor 51 by the back electromotive force constant Ke, and outputs the motor angular velocity ω to the steering angular velocity estimation unit 53.
The first arithmetic unit 50, the subtractor 51, and the second arithmetic unit 52 constitute a motor angular velocity estimator 60 (see FIG. 2).
[0069]
Next, the steering angular speed estimation unit 53 calculates the steering angular speed Q by dividing the motor angular speed ω by the reduction ratio G of the speed reducer 5.
In this way, the calculated (estimated) steering angular velocity Q is supplied to the convergence control unit 81.
[0070]
(Convergence control)
Next, as shown in FIG. 2, the CPU 21 further includes functions of a convergence control unit 81 and a hand release determination unit 82, which will be described.
[0071]
First, the convergence control unit 81 will be described.
As shown in FIG. 4, the convergence control unit 81 includes a target steering angle setting unit 86, a target steering angular velocity setting unit 87, a target convergence current setting unit 88, and subtracters 90 and 91.
[0072]
The convergence control unit 81 receives the vehicle speed V detected from the vehicle speed sensor 16 and the steering angle θ detected from the steering angle sensor 17 and the steering angular velocity Q.
[0073]
Then, the convergence control unit 81 determines a target convergence current Ihd * for causing the steering wheel 1 to converge to a substantially neutral position based on the input vehicle speed V, steering angle θ, and steering angular speed Q.
[0074]
More specifically, as shown in FIG. 5, the target steering angle setting unit 86 includes a sign determination unit 92, a target steering absolute angle setting unit 93, a multiplier 94, and a target steering angle calculation unit 95.
[0075]
The target steering absolute angle setting unit 93 uses the target steering absolute angle setting map stored in advance in the ROM 22 based on the vehicle speed V, that is, the absolute value of the target steering angle θ * corresponding to the vehicle speed V, that is, the target steering absolute The angle | θ *** | is obtained and output to the multiplier 94. The target steering angle θ * is a value for returning the steering wheel 1 to the neutral position, and the neutral position includes a predetermined residual angle range.
[0076]
Specifically, the steering wheel 1 (steering wheel) is normally returned to the neutral position, that is, 0 degrees at medium and high speeds, but is returned to 0 degrees at low speeds as compared with the conventional hydraulic power steering apparatus. Therefore, it is set so as to have a certain residual angle without returning to the neutral position completely.
[0077]
For this reason, the target steering absolute angle setting unit 93 sets the target steering absolute angle setting map so that the steering wheel 1 returns from the neutral position to a predetermined residual angle range when the steering wheel 1 is steered at a low vehicle speed. Set the steering absolute angle | θ *** |. The calculated target steering absolute angle | θ *** | increases as the vehicle speed V decreases, and at a predetermined vehicle speed V or higher, the target steering absolute angle | θ *** |
[0078]
The sign determination unit 92 determines the sign based on the steering angle θ and outputs the sign signal to the multiplier 94. That is, when the steering angle θ indicates right steering, +1 is output to the multiplier 94, while when the steering angle θ indicates left steering, −1 is output to the multiplier 94.
[0079]
The multiplier 94 multiplies the sign signal from the sign determination unit 92 and the target steering absolute angle | θ *** | from the target steering absolute angle setting unit 93. Then, the target steering absolute angle | θ *** | is given a sign and is output to the target steering angle calculation unit 95 as the provisional target steering angle θ **.
[0080]
The target steering angle calculator 95 outputs the target steering angle θ * to the subtracter 90 shown in FIG. 4 based on the provisional target steering angle θ ** and the steering angle θ.
Here, specifically, how to set the target steering angle θ * in the target steering angle calculation unit 95 will be described according to a flowchart (see FIG. 6) of a target steering angle calculation routine executed by the CPU 21.
[0081]
First, in S21, the provisional target steering angle θ ** is read. Next, in S22, the actual steering absolute angle (that is, the value obtained by taking the absolute value of the steering angle θ) | θ | takes the provisional target steering absolute angle (that is, the absolute value of the provisional target steering angle θ **). Value) | θ ** | That is, the magnitude relation between the provisional target steering angle θ ** and the current steering angle θ is determined.
[0082]
If the current steering angle θ is closer to the neutral position than the provisional target steering angle θ **, in other words, if the steering absolute angle | θ | is smaller than the provisional target steering absolute angle | θ ** | | <| Θ ** |, ie, the determination in S22 is YES), the process proceeds to S23. In step S23, the actual steering angle θ is set as the target steering angle θ * (θ * = θ) and output.
[0083]
On the other hand, when the temporary target steering angle θ ** is closer to the neutral position than the current steering angle θ, that is, when the steering absolute angle | θ | is equal to or larger than the temporary target steering absolute angle | θ ** | | θ | ≧ | θ ** |, ie, the determination in S22 is NO), the process proceeds to S24. In S24, the provisional target steering angle θ ** is set as the target steering angle θ * (θ * = θ **) and output.
[0084]
Next, as shown in FIG. 4, the subtractor 90 calculates a deviation (hereinafter referred to as “steering angle deviation”) Δθ from the target steering angle θ * and the steering angle θ, and a target steering angular velocity setting unit. Output to 87. The target steering angular velocity setting unit 87 receives the steering angular deviation Δθ and the vehicle speed V, obtains a target steering angular velocity Q * based on a target steering angular velocity setting map stored in advance in the ROM 22, and outputs the target steering angular velocity Q * to the subtracter 91. . The target steering angular speed setting map is a three-dimensional map composed of a steering angular deviation Δθ, a vehicle speed V, and a target steering angular speed Q *, and the target steering angular speed Q * is determined according to the steering angular deviation Δθ and the vehicle speed V. The In the present specification, hereinafter, the capital letter Q is used to mean angular velocity.
[0085]
The subtracter 91 receives the target steering angular velocity Q * and the steering angular velocity Q. Then, the subtractor 91 calculates the deviation (hereinafter referred to as “steering angular velocity deviation”) ΔQ and outputs it to the target convergence current setting unit 88.
[0086]
The target convergence current setting unit 88 includes first to third convergence current setting units 96 to 98, an integrator 99, a differentiator 100, and an adder 108.
The first convergence current setting unit 96 receives the vehicle speed V and the steering angular velocity deviation ΔQ. The first convergence current setting unit 96 calculates a first convergence current Ihd1 * using a first convergence current setting map stored in advance in the ROM 22, and outputs the first convergence current Ihd1 * to the adder. The first convergence current setting map is a three-dimensional map including a steering angular velocity deviation ΔQ, a vehicle speed V, and a first convergence current Ihd1 *.
[0087]
Then, according to the map, the first convergence current Ihd1 * proportional to the steering angular velocity deviation ΔQ is set according to the vehicle speed V and the steering angular velocity deviation ΔQ. That is, the first convergence current Ihd1 * is output to the adder 108 by so-called proportional control (hereinafter referred to as P control) by the first convergence current setting unit 96.
[0088]
The second convergence current setting unit 97 receives the vehicle speed V and the steering angular velocity deviation integrated value sum_ΔQ obtained by integrating the steering angular velocity deviation ΔQ with the integrator 99. The second convergence current setting unit 97 calculates the second convergence current Ihd2 * using the second convergence current setting map stored in advance in the ROM 22 and outputs the second convergence current Ihd2 * to the adder 108. The second convergence current setting map is a three-dimensional map including a steering angular velocity deviation integrated value sum_ΔQ, a vehicle speed V, and a second convergence current Ihd2 *. Then, according to the map, a second convergence current Ihd2 * proportional to the steering angular velocity deviation integrated value sum_ΔQ is set according to the vehicle speed V and the steering angular velocity deviation integrated value sum_ΔQ. That is, the second convergence current Ihd2 * is output to the adder 108 by so-called integration control (hereinafter referred to as I control) by the integrator 99 and the second convergence current setting unit 97.
[0089]
The third convergence current setting unit 98 receives the vehicle speed V and the steering angular velocity deviation differential value d_ΔQ obtained by differentiating the steering angular velocity deviation ΔQ with the differentiator 100. The third convergence current setting unit 98 calculates a third convergence current Ihd3 * using a third convergence current setting map stored in advance in the ROM 22 and outputs the third convergence current Ihd3 * to the adder 108. The third convergence current setting map is a three-dimensional map including the steering angular velocity deviation differential value d_ΔQ, the vehicle speed V, and the third convergence current Ihd3 *. Then, according to the map, a third convergence current Ihd3 * proportional to the steering angular velocity deviation differential value d_ΔQ is set according to the vehicle speed V and the steering angular velocity deviation differential value d_ΔQ. That is, the third converged current Ihd3 * is output to the adder 108 by so-called differential control (hereinafter referred to as D control) by the differentiator 100 and the third convergent current setting unit 98.
[0090]
The adder 108 outputs the target convergence current Ihd * calculated by adding the first to third convergence currents Ihd1 * to Ihd3 * to the multiplier 83 as shown in FIG.
[0091]
Therefore, in this embodiment, the target steering angle θ * is set according to the steering angle θ and the vehicle speed V, and the target steering is determined based on the deviation (steering angle deviation Δθ) between the target steering angle θ * and the steering angle θ and the vehicle speed V. An angular velocity Q * is set, and the target convergence current Ihd * is controlled by the deviation (steering angular velocity deviation ΔQ) between the target steering angular velocity Q * and the steering angular velocity Q and the vehicle speed V (hereinafter, this control is referred to as convergence control).
[0092]
(Release judgment)
Next, the hand release determination unit 82 will be described.
A steering torque Th detected from the torque sensor 4 and phase-compensated by the phase compensator 30 is input to the hand release determination unit 82. Further, as shown in FIG. 9, the hand release determination unit 82 includes a hand release determination map. Then, using this map, when the steering torque Th is close to 0, that is, when the hand is touching the steering wheel 1 lightly or when it is released, “1” is output to the multiplier 83. To do. On the other hand, when the steering torque Th exceeds a certain value X as in | Th |> X (X is a constant), “0” is output to the multiplier 83.
[0093]
As shown in FIG. 2, the multiplier 83 receives the target convergence current Ihd * from the convergence control unit 81 and the output signal “1” or “0” output from the hand-off determination unit 82 and multiplies them. When the output signal from the hand release determination unit 82 is “1”, the target convergence current Ihd * is output to the adder 39. On the other hand, if the output signal from the hand release determination unit 82 is “0”, a signal “0” is output to the adder 39.
[0094]
(Flow chart of convergence control)
Next, a flowchart of a series of processes executed by the CPU 21 in the convergence control will be briefly described with reference to FIGS. This flowchart is a process until the target convergence current Idh * set by the convergence control unit 81 and the hand release determination unit 82 is output to the adder 39.
[0095]
In S101, the vehicle speed V detected from the vehicle speed sensor 16 is calculated, and in S102, the steering angle θ is calculated based on the detection signal of the steering angle sensor 17.
In the next S103, the target steering angle θ * is obtained based on the vehicle speed V and the steering angle θ (processing of the target steering angle setting unit 86).
[0096]
Next, in S104, a steering angle deviation Δθ (= θ * −θ) between the target steering angle θ * obtained in S103 and the steering angle θ obtained in S102 is calculated (processing of the subtractor 90). In S105, the target steering angular velocity Q * is calculated based on the vehicle speed V and the steering angle deviation Δθ (processing of the target steering angular velocity setting unit 87).
[0097]
In S106, a steering angular velocity deviation ΔQ (= Q * -Q) between the target steering angular velocity Q * and the steering angular velocity Q is obtained (processing of the subtractor 91).
In S107 to S112, the target convergence current Ihd * is set. Note that S107 to S112 correspond to the processing of the target convergence current setting unit 88.
[0098]
In S107, P control is performed based on the steering angular velocity deviation ΔQ and the vehicle speed V, and the first converged current Ihd1 * by the P control is calculated (processing of the first converged current setting unit 96).
[0099]
In S108, ΔQ × t is added to the integrated value of steering angular velocity deviation ΔQ (that is, steering angular velocity deviation integrated value) sum_ΔQ in the previous control cycle, and updated as the steering angular velocity deviation integrated value sum_ΔQ in the current control cycle. That is, integration processing is performed (processing of the integrator 99). Note that t is a calculation cycle (that is, a control cycle of this control flow).
[0100]
In S109, based on the steering angular velocity deviation integrated value sum_ΔQ and the vehicle speed V obtained in S108 in the current control cycle, I control is performed to calculate a second converged current Ihd2 * by the I control (second converged current setting unit 97). Processing).
[0101]
In S110, the differential value of the steering angular velocity deviation ΔQ (that is, the steering angular velocity deviation differential value) d_ΔQ = (ΔQ−pre_ΔQ) / t is calculated. ΔQ is a value at the current control cycle, and pre_ΔQ is a value at the previous control cycle.
[0102]
Then, ΔQ at the current control cycle is updated as pre_ΔQ at the previous control cycle (processing of the differentiator 100).
Then, in S111, D control is performed based on the steering angular velocity deviation differential value d_ΔQ and the vehicle speed V, and a third converged current Ihd3 * by D control is calculated (processing of the third converged current setting unit 98).
[0103]
In S112, a target convergence current Ihd * (= Ihd1 * + Ihd2 * + Ihd3 *) obtained by synthesizing the PID control is obtained (processing of the adder 108).
In S113, hand release determination is performed based on the steering torque Th, and a gain (that is, a value of “0” or “1”) η is calculated (processing of the hand release determination unit 82). At this time, if it is determined that the hand is released, the gain η is “1”. If not (that is, if the vehicle is steered or steered), the gain η is “0”.
[0104]
In S114, it is determined that steering / holding is in progress, that is, when the convergence control operation is prohibited (gain η = 0, processing of multiplier 83), the integral term used in I control in S115 (that is, updated in S108) This time, the steering angular velocity deviation integral value sum_ΔQ) at the time of the control cycle is cleared to 0 to prevent malfunction due to the integral term when the convergence control is enabled again. In FIG. 4, clearing the steering angular velocity deviation integrated value sum_ΔQ) to 0 is performed by inputting a reset signal from the hand-off determination unit 82 to the integrator 99.
[0105]
In S116, the target convergence current Ihd * obtained in S112 is corrected with the gain η (= “1”) obtained in the hand-off determination to obtain the final target convergence current Ihd *. That is, during the steering / holding operation, the target convergence current Ihd * is corrected to 0 and the convergence control is prohibited. In the case of letting go, convergence control is performed.
[0106]
As shown in FIG. 2, the adder 39 outputs the result of multiplication from the multiplier 83 (that is, the output signal of the target convergence current Ihd * or “0”) and the assist current command value I from the current command value calculation unit 31. Are input, added, and output to the PI control unit 40.
[0107]
Here, when the steering wheel 1 is steered or maintained and a predetermined steering torque Th is detected, an output signal of “0” is output from the hand release determination unit 82. For this reason, the assist current command value I is output from the adder 39 to the PI control unit 40 as a motor current command value.
[0108]
On the other hand, when the hand is lightly touching the steering wheel 1 or when the hand is released, the steering torque Th is not input to the current command value calculation unit 31, and even if it is input, it becomes a very small value. . For this reason, the assist current command value I is not input to the adder 39. Even if it is input, it is a slight value. Accordingly, at this time, the target convergence current Ihd * is added to the assist current command value I and output to the PI control unit 40 as a motor current command value.
[0109]
Thereafter, the CPU 21 drives and controls the motor 6 based on the motor current command value via the PI control unit 40 and the PWM calculation unit 38. Therefore, even if the steering wheel 1 is released while being steered by a certain steering angle during traveling, the steering wheel 1 is always set to a set steering angle at a steering angular speed that is stably set from high speed to low speed by convergence control. Can be converged.
[0110]
According to the control device 20 of the electric power steering apparatus of the above embodiment, the following effects can be obtained.
(1) In the present embodiment, the CPU 21 sets the target steering angle θ * for returning the steering wheel 1 (steering wheel) to the neutral position based on the steering angle θ and the vehicle speed V as the target steering angle setting means. I made it. Further, the CPU 21 sets an ideal target steering angular velocity Q * as a target steering angular velocity setting means according to the deviation Δθ between the target steering angle θ * and the steering angle θ and the vehicle speed V. Further, the CPU 21 sets the target convergence current Ihd * based on the deviation ΔQ (steering angular velocity deviation, the same applies hereinafter) between the target steering angular velocity Q * and the steering angular velocity Q (actual steering angular velocity) as target convergence current setting means. did.
[0111]
As a result, if the steering angular velocity Q (actual steering angular velocity) is smaller than the target steering angular velocity Q *, the target convergence current Ihd * increases to assist the steering angular velocity to increase. On the other hand, when the steering angular velocity Q (actual steering angular velocity) is larger than the target steering angular velocity Q *, the polarity of the target convergence current Ihd * is reversed and the steering angular velocity is reduced. (Angular velocity) is controlled to match the target steering angular velocity Q *.
[0112]
That is, according to this control, the position of the steering angle to be returned and the steering angular velocity at that time can be controlled simultaneously, and the function of adjusting the convergence current by the target convergence current setting unit 88 works even if the road surface reaction force or the like changes. The steering wheel 1 can be converged to the steering angle set at the steering angular velocity that is always set stably.
[0113]
(2) In the present embodiment, the CPU 21 sets the target steering angular velocity Q * according to the vehicle speed V as the target steering angular velocity setting means.
As a result, the target steering angular velocity Q * corresponding to the vehicle speed can be obtained, and the effect (1) can be achieved in accordance with the vehicle speed.
[0114]
(3) In the present embodiment, the CPU 21 performs the I control based on the deviation ΔQ between the target steering angular velocity Q * and the steering angular velocity Q (actual steering angular velocity) as the target convergence current setting means, thereby setting the target convergence current Ihd *. Was set.
[0115]
As a result, if the target convergence current Ihd * is set without applying I control, an offset occurs between the target steering angular velocity Q * and the steering angular velocity Q (actual steering angular velocity), and the target steering angular velocity Q * is not reached. In this control, there is no such case, and by adding the second convergence current Ihd2 * obtained for the integration of the deviation ΔQ between the target steering angular velocity Q * and the steering angular velocity Q (actual steering angular velocity), The target steering angular velocity Q * can be set.
[0116]
(4) In the present embodiment, the CPU 21 performs the D control based on the deviation ΔQ between the target steering angular velocity Q * and the steering angular velocity Q (actual steering angular velocity) as the target convergence current setting means, thereby making the target convergence current Ihd *. And the steering angular velocity Q (actual steering angular velocity) quickly follows the target steering angular velocity Q *.
[0117]
As a result, if the target convergence current Ihd * is set without applying D control, a response delay occurs between the target steering angular velocity Q * and the steering angular velocity Q (actual steering angular velocity). According to this control, such a situation does not occur, and the target steering angular velocity is obtained by adding the third convergence current Ihd3 * obtained based on the differential ΔQ between the target steering angular velocity Q * and the steering angular velocity Q (actual steering angular velocity). Follow-up performance improves.
[0118]
(5) In the present embodiment, the CPU 21 uses the first converged current Ihd1 * and the second converged current Ihd2 * as the target convergent current setting means according to the vehicle speed V in any of P control, I control, and D control. The third convergent current Ihd3 * was determined.
[0119]
As a result, the target convergence current Ihd * corresponding to the vehicle speed V can be obtained.
(6) In the present embodiment, the target convergence current setting unit 88 obtains the target convergence current Ihd * by PID control based on the deviation ΔQ between the target steering angular velocity Q * and the steering angular velocity Q (actual steering angular velocity).
[0120]
As a result, the effects (3) and (4) can be obtained simultaneously.
(7) In the present embodiment, the CPU 21 determines whether to release the steering wheel 1 (steering wheel) based on the steering torque Th or whether to steer / hold the steering as the hand release determining means, and based on the determination result, The output of the target convergence current Ihd * is enabled or suppressed.
[0121]
If the hand release determination is not performed, the target convergence current Ihd * for returning the steering wheel 1 toward the neutral position is added to the assist current command value I, so that the assist torque by the motor 6 is reduced during the turning steering. The phenomenon which becomes heavier occurs.
[0122]
However, in this control, when the steering is turned (when the steering torque Th is greater than or equal to a certain value X such as | Th |> X in the hand release determination), “0” is output to the multiplier 83, and the target convergence current is set. Since addition of Ihd * is prohibited, a reduction in the auxiliary torque by the motor 6 is prevented, and the steering does not become heavy. On the other hand, when the steering wheel 1 is lightly touched or when the steering wheel 1 is released, the target convergence current Ihd * is activated, and the steering wheel 1 can be returned to the neutral position at a predetermined steering angular velocity. .
[0123]
(8) In the present embodiment, the CPU 21 performs steering / holding determination as the hand release determination unit, and suppresses the output of the target convergence current of the target convergence current setting unit, and thus the integral term obtained by the I control. Was reset.
[0124]
If this process is not performed, the difference ΔQ between the target steering angular velocity Q * set by the target steering angular velocity setting unit 87 and the steering angular velocity Q (actual steering angular velocity) regardless of whether the steering wheel 1 is released or not. On the other hand, the deviation ΔQ is integrated in the integrator 99 in the previous stage of the second convergence current setting unit 97 of the target convergence current setting unit 88, and the second integration which is the integration of the deviation ΔQ at the moment when it is determined to be in the released state. The convergence current Ihd2 * flows excessively, and a phenomenon may occur in which the steering angular velocity Q (actual steering angular velocity) does not coincide with the target steering angular velocity Q *.
[0125]
According to the present control, the integration term in the PID control is validated only when it is determined that there is no such a thing and the hand-off determination state, and when the steering / steering is performed, By inputting a reset signal from the hand release determination unit 82, the integral term in the PID control is kept at zero.
[0126]
As a result, the target convergence current Ihd * can be set so that the target steering angular velocity Q * and the steering angular velocity Q (actual steering angular velocity) coincide with each other when the steering / holding state is shifted to the released state.
[0127]
(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS.
In addition, about the same structure as 1st Embodiment, or the structure which corresponds, the same code | symbol is attached | subjected and the description is abbreviate | omitted. Also in this embodiment, it is assumed that the electric power steering device has the same hardware configuration as that of the first embodiment.
[0128]
FIG. 10 is different from the first embodiment in that a detection signal from the steering angle sensor 17 is input to the subtracter 90 via the phase compensation unit 84. That is, the value after the phase compensation of the detection signal from the steering angle sensor 17 in the phase compensation unit 84 to advance the phase according to the steering angular velocity Q is the steering angle θ. The phase compensation unit 84 corresponds to phase compensation means.
[0129]
More specifically, the phase compensator 84 includes a differentiator 70, a gain multiplier 71, and an adder 72 as shown in FIG.
The differentiator 70 obtains the steering angular velocity Q by differentiating the steering angle signal from the steering angle sensor 17, and the gain multiplier 71 supplies the adder 72 with a value QT obtained by multiplying the steering angular velocity Q by a preset gain T. Output. The adder 72 adds the QT to the steering angle signal to obtain a value obtained by advancing the phase (in this embodiment, this is referred to as the steering angle θ), and outputs the value to the subtracter 90. As the gain T, a value obtained in advance through experiments or the like is adopted and stored in the ROM 22 in advance.
[0130]
In the present embodiment, the CPU 21 corresponds to each means of the first embodiment and also corresponds to a phase compensation means.
Therefore, according to the control device 20 of the electric power steering apparatus of the second embodiment, the following effects can be obtained.
[0131]
(1) In this embodiment, the CPU 21 compensates the phase so as to advance the phase of the detection signal detected by the steering angle sensor 17 as the phase compensation means. Then, the CPU 21 sets the target steering angle θ * for returning the steering wheel 1 to the neutral position based on the phase-compensated steering angle θ and the vehicle speed V as the target steering angle setting means.
[0132]
If phase compensation is not performed, if control is performed using the steering angle signal detected by the steering angle sensor 17, it may not be possible to converge to the target steering angle θ * at a predetermined steering angular velocity due to the influence of the phase delay. .
[0133]
According to the present control, such a situation does not occur, and the phase of the steering angle is compensated by the steering angular velocity, so that the target steering angle θ * can be converged at the predetermined steering angular velocity.
[0134]
In addition, you may change embodiment of this invention as follows.
In each of the above embodiments, the actual steering angular velocity (steering angular velocity Q) input to the subtractor 91 is calculated from the motor voltage equation from the motor terminal voltage Vm and the motor current Im, but is detected by the steering angle sensor 17. The steering angle θ may be obtained by differentiation.
[0138]
In the first embodiment, according to the hand release determination of the CPU 21, “0” is given to the multiplier 83 at the time of turning steering (when the steering torque Th is equal to or greater than a certain value X such as | Th |> X in the hand release determination). The output is suppressed by prohibiting addition of the target convergence current Ihd *. Alternatively, instead of “0”, the target convergence current Ihd * may be multiplied by a gain (> 0) equal to or less than “1”, and the value may be reduced.
[0139]
【The invention's effect】
  According to the first aspect of the invention, the handle can be converged toward the neutral position at a predetermined steering angular velocity. As a result, the road surface reaction force etc. changes and the restoring force to return the handle to the neutral position direction becomes weak, even if the handle is difficult to return, or conversely, the restoring force is strong and the handle quickly returns to the neutral position direction. Target convergence current setting even if trying tomeansSince the convergence current is set so as to return at a predetermined steering angular velocity, the steering wheel can always be converged to a predetermined steering angle position at a predetermined steering angular velocity stably.
When differential control is not applied, a response delay occurs between the target steering angular velocity and the steering angular velocity (actual steering angular velocity). According to the first aspect of the present invention, the target convergence current is obtained without performing differential control. Compared with the case where is set, the response delay of the actual steering angular velocity with respect to the target steering angular velocity does not occur, and the followability to the target steering angular velocity is improved.
Furthermore, according to the first aspect of the invention, a target convergence current corresponding to the vehicle speed can be obtained.
[0140]
According to the second aspect of the present invention, the target steering angular speed setting means sets the target steering angular speed according to the vehicle speed, so that the steering wheel is always stably driven at the predetermined steering angular speed to the position of the predetermined steering angle according to the vehicle speed. Can converge.
[0143]
  ContractClaim3According to the invention, since the target convergence current is suppressed during the turning steering, the reduction of the auxiliary torque is prevented and the steering does not become heavy. On the contrary, the handle is lightly touched or released. If so, the target convergence current works, and the steering wheel can be returned toward the neutral position at a predetermined steering angular velocity.
[0144]
  Claim4According to the invention, the target convergence current can be set so that the target steering angular velocity and the actual steering angular velocity coincide with each other when the steering / holding state is shifted to the hand-off state.
[0145]
  Claim5According to the invention, since the steering angle is phase-compensated by the steering angular velocity, it is possible to converge to the target steering angle θ * at a predetermined steering angular velocity.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an electric power steering device and a control device according to the present invention.
FIG. 2 is a functional block diagram of the control device.
FIG. 3 is a functional block diagram of a current command value calculation unit.
FIG. 4 is a functional block diagram of a convergence control unit.
FIG. 5 is a functional block diagram of a target steering angle setting unit.
FIG. 6 is a flowchart of a target steering angle calculation routine.
FIG. 7 is a flowchart of processing executed in convergence control.
FIG. 8 is a flowchart of processing executed in the same convergence control.
FIG. 9 is a functional block diagram of a hand release determination unit.
FIG. 10 is a functional block diagram of a convergence control unit according to another embodiment.
FIG. 11 is a functional block diagram of a phase compensation unit.
FIG.Schematic of the conventional electric power steering apparatus and its control apparatus.
FIG. 13Explanatory drawing of calculation of assist electric current command value I. FIG.
FIG. 14The functional block diagram of CPU of the conventional control apparatus.
FIG. 15The functional block diagram which performs the steering wheel return calculation in a steering wheel return controller.
FIG. 16The functional block diagram which performs the damper electric current calculation in a damper controller.
FIG. 17The functional block diagram of a handle return controller.
[Explanation of symbols]
  1 ... steering wheel, 4 ... torque sensor, 6 ... motor,
  21 ... CPU (target steering angle setting means, target steering angular velocity setting means, target convergence current setting means, hand release determination means, phase compensation means).

Claims (5)

Target steering angle setting means for setting a target steering angle for returning the steering wheel to the neutral position based on the steering angle and the vehicle speed;
Target steering angular velocity setting means for setting a target steering angular velocity based on the target steering angle and the deviation of the steering angle and the vehicle speed;
Target convergence current setting means for setting a target convergence current based on a deviation between the target steering angular velocity and the steering angular velocity;
With
The target converging current setting means when setting the target convergent current based on a deviation of the target steering angular velocity and steering angular velocity, sets a target convergence current proportional control, integral control, and on the basis of your a differential system,
The control apparatus for an electric power steering apparatus, wherein the target convergence current setting means performs proportional control, integration control, and differentiation control by performing correction according to the vehicle speed to set a target convergence current .   2. The control device for an electric power steering apparatus according to claim 1, wherein the target steering angular speed setting means sets the target steering angular speed by performing correction according to the vehicle speed. A hand release determining means for determining whether to release the handle based on the steering torque or determining whether to steer or hold the steering,
3. The electric power steering apparatus according to claim 1, wherein the hand release determination unit enables or suppresses the output of the target convergence current of the target convergence current setting unit based on the determination result . Control device. When the hand release determination means determines steering / holding and suppresses the output of the target convergence current setting means, the hand release determination means is obtained by integral control of the target convergence current setting means. 4. The control device for an electric power steering apparatus according to claim 1, wherein the integral term is reset . Phase compensation means for compensating the phase of the steering angle,
The target steering angle setting means, a phase compensation means is請 Motomeko 1 to claim 4, characterized in that for setting a target steering angle for returning the steering wheel to the neutral position based on the steering angle and the vehicle speed obtained by the phase compensation The control apparatus of the electric power steering apparatus of any one of them .

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