JP3901928B2 - 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]
FIG. 16 shows an outline of a control device according to an electric power steering device used in a conventional automobile or the like.
[0003]
A torsion bar 43 is provided on the steering shaft 42 connected to the steering wheel 41. A torque sensor 44 is attached to the torsion bar 43. When the steering shaft 42 rotates and a force is applied to the torsion bar 43, the torsion bar 43 is twisted according to the applied force, and the torque sensor 44 detects the twist.
[0004]
A reduction gear 45 is fixed to the steering shaft 42. A gear 47 attached to the rotating shaft of the motor 46 is engaged with the speed reducer 45. Further, a pinion shaft 48 is fixed to the speed reducer 45. A pinion 49 is fixed to the tip of the pinion shaft 48, and the pinion 49 meshes with the rack 51.
[0005]
Tie rods 52 are fixed to both ends of the rack 51. Knuckles 53 are rotatably connected to both ends of the tie rod 52. A front wheel 54 is fixed to the knuckle 53. The knuckle 53 is rotatably connected to the cross member 55.
[0006]
Therefore, when the motor 46 rotates, the number of rotations is reduced by the speed reducer 45 and transmitted to the pinion shaft 48, and is transmitted to the rack 51 via the rack and pinion mechanism 50. Then, the knuckle 53 connected to the tie rod 52 fixed to the rack 51 moves rightward or leftward depending on the rotation direction of the motor 46. A vehicle speed sensor 56 is provided on the front wheel 54.
[0007]
The rotational speed and rotational direction of the motor 46 are determined by positive and negative assist currents supplied from the motor drive device 57. The assist current supplied from the motor drive device 57 to the motor 46 is calculated by the assist current determination means 58 that controls the motor drive device 57. The assist current determining means 58 is composed of a CPU or the like, and calculates the steering torque of the steering wheel 41 from the detection signal from the torque sensor 44 and calculates the vehicle speed from the detection signal from the vehicle speed sensor 56. .
[0008]
Then, the assist current determination means 58 calculates an assist current (assist current command value) based on the calculated steering torque and vehicle speed. This calculation is obtained from an assist map stored in advance in a memory in the assist current determining means 58. Then, the assist current determining means 58 controls the current of the motor 46 that generates assist torque so as to become the assist current (assist current command value).
[0009]
However, the assist map is a value set in a specific road reaction force situation (for example, a flat asphalt road), and the road reaction force situation changes, that is, a low μ road such as a snow road or a decrease in tire air pressure. When the tire specifications (wear, tire type, etc.) change, the road surface reaction force changes, which changes the steering force, leading to a deterioration in feeling.
[0010]
The steering torque rise with respect to the steering angle (build-up feeling) is used as an index for determining steering feeling. In the control device, the assist current is determined for the steering torque and the vehicle speed. On the other hand, there is a problem that it is very difficult to set map data for giving a predetermined steering torque (that is, giving a build-up feeling).
[0011]
In addition, if disturbance torque due to inertia or viscosity due to motors, speed reducers, etc. is generated by fast steering, etc., the assist current determination means cannot cancel this disturbance torque, so control to cancel inertia and viscosity separately is necessary. It was.
[0012]
Further, there is a problem that the control of the hysteresis of the steering torque when steering left and right cannot be freely set, and the degree of freedom for realizing an ideal steering feeling is low.
[0013]
Therefore, in order to solve these problems, the applicant sets a target steering torque according to the steering angle and the vehicle speed, and determines an assist current command value based on the steering torque, the target steering torque, and the motor current. A device for controlling a motor (hereinafter referred to as MA-MT control) has been proposed.
[0014]
In other words, a steering angle sensor 59 (indicated by a two-dot chain line in FIG. 16) for detecting the steering angle of the steering shaft 42 is provided, and the assist current determining means 58 of this device determines the steering angle and the vehicle speed from the steering angle sensor 59. Based on this, the target steering torque is set.
[0015]
Further, an assist current (assist current command value) is calculated based on the steering torque, the target steering torque, and the motor current of the motor 46.
As a result, the target steering torque with respect to the vehicle speed and the steering angle can be freely set, the inclination of the steering torque with respect to the steering angle can be easily set, and the fit of the build-up feeling can be easily performed. Even if the road surface reaction force decreases or the actual steering torque decreases or increases due to the viscosity or inertia of the motor 46 or the speed reducer 45 connected to the motor 46, the steering torque becomes the target steering torque. Thus, the function of adjusting the assist current (assist current command value) works to provide a stable operation feeling.
[0016]
[Problems to be solved by the invention]
By the way, in the above apparatus, it is assumed that the vehicle is steered by a certain steering angle while traveling and the steering wheel (handle) 41 is released. Then, when setting the target steering torque, the target steering torque at the current steering angle and vehicle speed is set. However, by letting it go, the steering torque (actual steering torque) becomes zero, and the assist current determination means 58 reduces the motor current for assisting to become zero in order to obtain the target steering torque. When the handle 41 is released, the handle 41 is returned to the neutral position by self-aligning (SAT) acting on the tire. However, this SAT is small when traveling at low speed, the internal friction of the electric power steering device is greater, the handle 41 stops halfway, and this SAT is large when traveling at high speed, and the inertia of the rotating body such as the motor 46 and the reducer 45 is high. As a result, even if there is internal friction of the electric power steering device, the handle 51 overshoots beyond the neutral position of the handle 41, and it takes time for the handle 41 to converge to the neutral position, causing the vehicle to become unstable. .
[0017]
Even if the handle 41 is not released during high-speed driving, there is a region where the steering torque (actual steering torque) becomes small when the handle 41 is near the neutral position, and the assist current command value by the above control becomes zero. There is a problem that the handle 41 overshoots due to the inertia of the rotating body such as the machine 45 and the convergence of the handle 41 is deteriorated.
[0018]
The present invention has been made in order to solve the above-mentioned problems. The object of the present invention is to improve the steering wheel return characteristic during low-speed driving and to perform high-speed driving in MA-MT control when the steering torque is not detected or is small. It is sometimes an object to provide a control device for an electric power steering device that improves the convergence of the steering wheel.
[0019]
[Means for Solving the Problems]
In order to solve the above problems, the invention described in claim 1 is a control device for an electric power steering apparatus having a control means for driving and controlling a motor based on a motor current command value, and based on the steering angle and the vehicle speed. Target steering torque setting means for setting the target steering torque, assist current calculation means for calculating an assist current command value based on the steering torque, the target steering torque, and the motor current of the motor, and a steering angle and a vehicle speed. A target steering angle setting means for setting a target steering angle for returning the steering wheel to a neutral position based on the target steering angular speed setting means for setting a target steering angular speed based on a deviation between the target steering angle and the steering angle and a 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; A release determination unit that determines whether or not to release the handle based on the steering torque, based on a determination result of the release release determination unit, Target convergence current of target convergence current setting means Output The Enable or suppress, The gist of the control device for the electric power steering apparatus is that the motor current command value is added to the assist current command value.
[0021]
Claim 2 The invention of claim 1 The target convergence current setting means calculates a first convergence current proportional to the deviation between the target steering angular velocity and the steering angular velocity, and further calculates a second convergence current based on an integral value of the deviation between the target steering angular velocity and the steering angular velocity. The gist of the control device for the electric power steering apparatus is to set the target convergence current by adding both convergence currents.
[0022]
Claim 3 The invention of claim 1 The target convergence current setting means calculates a first convergence current proportional to the deviation between the target steering angular velocity and the steering angular velocity, and further calculates a third convergence current based on a differential value of the deviation between the target steering angular velocity and the steering angular velocity. The gist of the control device for the electric power steering apparatus is to set the target convergence current by adding both convergence currents.
[0023]
Claim 4 The invention of claim 1 The target convergence current setting means calculates a first convergence current proportional to a deviation between the target steering angular velocity and the steering angular velocity, and calculates a second convergence current based on an integral value of the deviation between the target steering angular velocity and the steering angular velocity. Further, the gist of the control device for the electric power steering apparatus is to calculate a third convergence current based on a differential value between the target steering angular velocity and the steering angular velocity, and to set the target convergence current by adding these convergence currents. It is.
[0024]
Claim 5 The invention of claim 1 to claim 1 4 In any one of the above, the neutral position includes a predetermined residual angle range, and when the vehicle speed is low, the target steering angle setting means sets the target steering angle so as to return the steering wheel within the residual angle range. The gist of the control device of the electric power steering apparatus for setting
[0025]
(Function)
According to the first aspect of the present invention, the target steering torque setting means sets the target steering torque based on the steering angle and the vehicle speed. The assist current calculation means calculates an assist current command value based on the steering torque, the target steering torque, and the motor current of the motor. 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 and the vehicle speed.
[0026]
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.
[0027]
The control means drives and controls the motor based on the motor current command value obtained by adding the target convergence current and the assist current command value.
further The hand release determining means determines whether to release the handle based on the steering torque. Based on the determination result of the hand release determination means, the output of the target convergence current of the target convergence current setting means is validated or suppressed, and the value obtained by adding to the assist current command value is used as the motor current command value. .
[0028]
Claim 2 According to the invention, the target convergence current setting means calculates the first convergence current proportional to the deviation between the target steering angular velocity and the steering angular velocity, and further, based on the integrated value of the deviation between the target steering angular velocity and the steering angular velocity. The current is calculated, and both convergent currents are added to set the target convergent current.
[0029]
Claim 3 According to the invention, the target convergence current setting means calculates the first convergence current proportional to the deviation between the target steering angular velocity and the steering angular velocity, and further the third convergence based on the differential value of the deviation between the target steering angular velocity and the steering angular velocity. The current is calculated, and both convergent currents are added to set the target convergent current.
[0030]
Claim 4 According to the invention, the target convergence current setting means calculates the first convergence current proportional to the deviation between the target steering angular velocity and the steering angular velocity, and the second convergence current based on the integrated value of the deviation between the target steering angular velocity and the steering angular velocity. Further, a third convergence current is calculated based on the differential value of the deviation between the target steering angular velocity and the steering angular velocity, and these convergence currents are added to set the target convergence current.
[0031]
Claim 5 According to this invention, the target steering angle setting means sets the target steering angle so as to return the steering wheel within the range of the remaining angle when the vehicle speed is low.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
Hereinafter, an embodiment in which the present invention is embodied in a control device for a rack assist type electric power steering device mounted on an automobile will be described with reference to FIGS.
[0033]
FIG. 1 schematically shows an electric power steering apparatus.
A torsion bar 3 is provided on a steering shaft 2 connected to a steering wheel 1 as a handle. For convenience of explanation, the steering wheel 1 is sometimes referred to as a handle 1 hereinafter. 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. A steering angle sensor 17 for detecting the steering angle θ of the steering shaft 2 is mounted on the steering shaft 2. These sensor outputs are supplied to the control device 20.
[0034]
A pinion shaft 8 is fixed to the steering shaft 2. 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. A tie rod 12 is fixed to both ends of the rack 10, and a knuckle 13 is rotatably connected to a tip portion 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. An electric motor (hereinafter referred to as a motor) 6 arranged coaxially with the rack 10 transmits the auxiliary steering force generated by the motor 6 to the rack 10 via the ball nut mechanism 6a.
[0035]
Accordingly, when the motor 6 rotates, the rotation number is reduced by the ball nut mechanism 6a and transmitted to the rack 10. 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.
[0036]
A vehicle speed sensor 16 is provided on the front wheel 14.
Next, the electrical configuration of the electric power steering apparatus is shown in FIG.
The torque sensor 4 outputs a signal indicating the steering torque Th of the steering wheel 1. The steering angle sensor 17 outputs a steering angle signal indicating the steering angle θ of the steering shaft 2. The vehicle speed sensor 16 outputs a detection signal relative to the rotational speed of the front wheel 14 indicating the vehicle speed V at that time. The controller 20 is electrically connected to a motor drive current sensor 18 that detects a drive current (motor current Im, corresponding to a motor current value) flowing through the motor 6. A signal indicating the current Im is supplied.
[0037]
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.
[0038]
Various control programs executed by the CPU 21 are stored in the ROM 22. The RAM 23 temporarily stores calculation processing results and the like when the CPU 21 performs calculation processing.
[0039]
A motor driving device 24 is connected to the output side of the control device 20 and drives the motor 6 based on a control signal from the control device 20. The motor driving device 24 includes a power element (not shown) such as an FET for performing PWM control based on a PWM calculation of the CPU 21 described later.
[0040]
The CPU 21 corresponds to a target steering torque setting unit, an assist current calculation unit, a target steering angle setting unit, a target steering angular speed setting unit, a target convergence current setting unit, and a hand release determination unit.
[0041]
Next, the assist control will be described with reference to FIGS.
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. To do.
[0042]
FIG. 2 is a control block diagram of the CPU 21. In this embodiment, the inside of the CPU 21 indicates a function executed by a program. For example, the phase compensator 30 is not an independent hardware, but represents a phase compensation function executed in the CPU 21. Similarly, FIG. 4, FIG. 7 to FIG. 10 and FIG. 14 show the processing functions executed by the CPU 21 by the program in a control block diagram, and do not mean an actual hardware configuration.
[0043]
Hereinafter, functions and operations of the CPU 21 will be described.
First, for convenience of explanation, vehicle speed sensitive assist control by MA-MT control will be described, and then convergence control will be described.
[0044]
(Vehicle speed sensitive assist control by MA-MT control)
As shown in FIG. 2, the CPU 21 includes phase compensators 30 and 35, a current command value calculation unit 31 as an assist current determination unit, a target steering torque setting unit 32 as a target steering torque setting unit, a subtractor 33, a current control unit 34, It has functions such as a target steering angle setting means, a target steering angular velocity setting means, and a convergence control section 81 as target convergence current setting means, a hand release determination section 82 as hand release determination means, a multiplier 83, an adder 84, and the like.
[0045]
The target steering torque setting unit 32 inputs the vehicle speed V from the vehicle speed sensor 16 and the steering angle signal from the steering angle sensor 17, and sets the target steering torque Th *. The steering angle signal is input to the target steering torque setting unit 32 via the phase compensator 35. That is, the phase compensator 35 compensates the phase of the steering angle signal output from the steering angle sensor 17 to advance the phase, and outputs it to the target steering torque setting unit 32 as the steering angle θ.
[0046]
More specifically, as shown in FIG. 4, the phase compensator 35 includes a differentiator 36, a gain multiplier 37, and an adder 38.
The differentiator 36 differentiates the steering angle signal from the steering angle sensor 17 to obtain the steering angular velocity S, and the gain multiplier 37 multiplies the steering angular velocity S by a preset gain T to the adder 38. Output. The gain T is a value obtained by a test or the like in advance so that a phenomenon that the steering torque (actual steering torque) Th with respect to the steering angle signal does not coincide with the target steering torque Th * does not occur due to the phase delay of the steering angle signal. It is determined based on. The adder 38 adds the ST to the steering angle signal and advances the phase (in this embodiment, this is referred to as the steering angle θ), and outputs the value to the target steering torque setting unit 32. ing.
[0047]
As shown in FIG. 5, the target steering torque setting unit 32 includes a plurality of target steering torque setting maps corresponding to a plurality of different predetermined vehicle speeds V. As the vehicle speed V becomes higher, the target steering torque setting map is set so that the inclination of the target steering torque Th becomes steeper than when the vehicle speed V is low.
[0048]
Specifically, how to set the target steering torque Th * will be described according to a flowchart (see FIG. 3) of a target steering torque setting routine executed by the CPU 21.
First, in S10, the steering angle θ is read. In S11, the current steering state is right steering (steering in the right direction), left steering (steering in the left direction), or in a state where the steering is maintained. In order to determine whether or not, the steering angle θ is differentiated to calculate the steering angular velocity dθ / dt.
[0049]
In the next S12, if the steering angular velocity is near zero (| dθ / dt | ≦ ε, ε is a constant that is a small value), it is determined that the steering is maintained (“YES” in S12). The steering direction determined in the previous control cycle in S17 (previous value steering direction) is set as the current steering direction, and the process proceeds to S14.
[0050]
If the steering angular velocity dθ / dt is not near zero (when “NO” is determined in S12), the steering direction is determined in S13 by looking at the sign of the steering angular velocity dθ / dt.
[0051]
Next, in step S14, a target steering torque setting map relating to a vehicle speed close to the vehicle speed V among a plurality of target steering torque setting maps stored in advance in the ROM 22 is examined for the vehicle speed V. The vehicle speed on the map side close to the vehicle speed V is set to V1 and V2 (V1 ≦ V <V2).
[0052]
As shown in FIG. 5, the target steering torque setting map is configured such that the target steering torque is obtained corresponding to the right steering and the left steering for each speed.
In the next S15, the temporary target steering torques Th1 * and Th2 * are obtained from the searched target steering torque setting maps of the vehicle speeds V1 and V2 according to the steering angle θ based on the steering direction previously determined in S13. In S16, a target steering torque Th * with respect to the vehicle speed V and the steering angle θ is calculated by a linear interpolation formula for the vehicle speed V.
[0053]
The linear interpolation formula is as follows.
Th * = (Th2 * −Th1 *) / (V2−V1) × (V−V1) + Th1 *
Next, the current command value calculation unit 31 will be described.
[0054]
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. Further, the vehicle speed V detected by the vehicle speed sensor 16, the motor current Im detected by the motor drive current sensor 18, and the target steering torque Th * from the target steering torque setting unit 32 are respectively input to the current command value calculation unit 31. .
[0055]
The current command value calculation unit 31 is based on the input steering torque Th, vehicle speed V, target steering torque Th *, and motor current Im, and a vehicle speed sensitive assist command value (assist that is a control target value of current supplied to the motor 6). I) corresponding to the current command value is determined.
[0056]
As shown in FIG. 7, the current command value calculation unit 31 includes a dead zone width setting unit 25 and a vehicle speed sensitive assist torque calculation unit 26.
Based on the vehicle speed V, the dead zone width setting unit 25 uses the dead zone map MP stored in advance in the ROM 22 as shown in FIG. To the unit 26. Note that the dead zone width map MP is a two-dimensional map composed of the vehicle speed V and the dead zone width T0. From the vehicle speed V, the dead zone width T0 is uniquely determined.
[0057]
As shown in FIG. 6, the vehicle speed sensitive assist torque calculation unit 26 determines that the target steering torque Th * obtained by the target steering torque setting unit 32 is equal to the dead band width T0 (that is, in FIG. 6, the dead band width T0 is −T0). Is within the range of T0), the vehicle speed sensitive assist command value (corresponding to the assist current command value, hereinafter referred to as the assist current command value) I is determined to be 0, and this value Is output to the subtractor 33.
[0058]
When the target steering torque Th * is outside the range of the dead zone width T0, the rack thrust calculated by the current steering torque Th and the motor current Im, and the rack thrust at the target steering torque Th * and the assist current command value I The assist current command value I is set so that is balanced.
[0059]
Hereinafter, a method of determining the assist current command value I in the control device 20 of the rack assist type electric power steering device will be described.
In the case of the rack assist type, the rack thrust F at the time of the steering torque Th and the motor current Im is obtained by the following equation (A).
[0060]
F = Fm + Fh (A)
Here, Fm is a thrust assisted by the motor 6, and Fh is a thrust by steering the steering wheel, which can be obtained by the following equations.
[0061]
Fm = 2π · Tm · ηb / L (B)
Fh = 2π · Th · ηp / St (C)
In (B) above, Tm represents the motor torque,
Tm = Kt × Im (D)
It is obtained by.
[0062]
Tm is the motor torque, ηb is the ball screw efficiency of the ball nut mechanism 6a, and L is the ball screw lead. Th is the steering torque, ηp is the rack and pinion gear efficiency of the rack and pinion mechanism 11, and St is the stroke ratio. Kt is a torque constant.
[0063]
Therefore, using the above equation (A), the rack thrust F at the vehicle speed V, the target steering torque Th * at the steering angle θ, and the assist current command value I (hereinafter, this thrust is expressed as F (Th *, I)). The assist current command value I is set so that the rack thrust F at the time of the steering torque Th and the motor current Im (hereinafter, this thrust is represented by F (Th, Im)) becomes equal.
[0064]
Substituting the above (B), (C), and (D) into F (Th *, I) = F (Th, Im) to obtain I, the following equation is obtained.
I = Im + (Th−Th *) L · ηp / (St · Kt · ηb)
The assist current command value I thus obtained is output to the adder 84.
[0065]
When the assist current command value I is opposite in sign to the target steering torque Th *, that is, reverse assist, the assist current command value I is determined to be zero and output to the adder 84.
[0066]
Accordingly, in the present embodiment, the target steering torque Th * is set according to the steering angle θ and the vehicle speed V, and the assist current command value I is controlled by the steering torque Th, the target steering torque Th *, and the motor current Im (MA− MT control).
[0067]
The adder 84 adds an assist current command value I output from the current command value calculation unit 31 by the MA-MT control and a target converged current Ihd * calculated by a convergent control described later to obtain a motor current command. The value Io is output to the subtracter 33.
[0068]
The subtractor 33 outputs a signal (corresponding to the assist current control value) corresponding to the difference between the motor current command value Io input from the adder 84 and the actual motor current Im to the current control unit 34.
[0069]
In the present embodiment, the current control unit 34 is configured to perform known PI control, and the motor is driven to perform feedback control based on a signal corresponding to the difference between the output of the subtractor 33 and the actual motor current Im. Supply to device 24. That is, the current control unit 34 performs PWM calculation so that the motor current becomes the motor current command value Io, and drives the motor 6 based on the calculation result. As a result, by controlling the drive of the motor 6 via the motor drive device 24, an appropriate assist force by the motor 6 can be obtained.
[0070]
(Convergence control)
Next, CPU21 is further provided with the function of the convergence control part 81 and the hand release determination part 82, and they are demonstrated.
[0071]
First, the convergence control unit 81 will be described.
As shown in FIG. 9, 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, a differentiator 89, and subtractors 90 and 91. 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 phase-compensated by the phase compensator 35. 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 and the steering angle θ.
[0072]
More specifically, as shown in FIG. 10, 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.
[0073]
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.
[0074]
Specifically, it is normal to return the steering wheel 1 to a neutral position, that is, to 0 degree at medium and high speeds, but it is unnatural compared to a conventional hydraulic power steering apparatus to return to 0 degrees at low speeds. Therefore, it is set so as to have a certain residual angle without returning to the neutral position completely.
[0075]
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 *** |
[0076]
The sign determination unit 92 determines a 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.
[0077]
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 **.
[0078]
The target steering angle calculator 95 outputs the target steering angle θ * to the subtracter 90 shown in FIG. 9 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. 11) of a target steering angle calculation routine executed by the CPU 21.
[0079]
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 relationship between the provisional target steering angle θ ** and the current steering angle θ is compared.
[0080]
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 S23, the actual steering angle θ is set as the target steering angle θ * (θ = θ *) and output.
[0081]
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.
[0082]
As shown in FIG. 9, 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 outputs it to the target steering angular velocity setting unit 87. To do. 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 including 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. Is done. In the present specification, hereinafter, the capital letter Q is used to mean angular velocity.
[0083]
The subtracter 91 receives the target steering angular velocity Q * and the steering angular velocity Q obtained by differentiating the steering angle θ by the differentiator 89. Then, the deviation (hereinafter referred to as “steering angular velocity deviation”) ΔQ is calculated by the subtractor 91 and output to the target convergence current setting unit 88.
[0084]
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 101.
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 101. 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 *. 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 converged current Ihd1 * is output to the adder 101 by so-called P control by the first converged current setting unit 96.
[0085]
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 101. 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 101 by so-called I control by the integrator 99 and the second convergence current setting unit 97.
[0086]
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 101. 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 convergence current Ihd3 * is output to the adder 101 by so-called D control by the differentiator 100 and the third convergence current setting unit 98.
[0087]
The adder 101 outputs a target convergence current Ihd * calculated by adding the first to third convergence currents Ihd1 * to Ihd3 * to the multiplier 83 as shown in FIG.
[0088]
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).
[0089]
Next, the hand release determination unit 82 will be described.
The steering torque Th detected from the torque sensor 4 is input to the hand release determination unit 82. Moreover, as shown in FIG. 14, 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 |> X (X is a constant) or more than a certain value X, “0” is output to the multiplier 83.
[0090]
As shown in FIG. 2, the multiplier 83 inputs the convergence current Ihd * from the convergence control unit 81 and the output signal “1” or “0” output from the hand release 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 84. On the other hand, when the output signal from the hand release determination unit 82 is “0”, a signal “0” is output.
[0091]
(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 processing 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 84.
[0092]
In S101, the vehicle speed V detected from the vehicle speed sensor is calculated, and in S102, the steering angle is obtained based on the detection signal of the steering angle sensor 17, phase compensation is performed in accordance with the steering angular velocity S, and the obtained steering angle is calculated as θ. (Processing of the phase compensator 35).
[0093]
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).
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).
[0094]
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).
And target convergence current Ihd * is set in S107-S112. Note that S107 to S112 correspond to the processing of the target convergence current setting unit 88.
[0095]
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).
[0096]
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 at the previous control cycle, and updated as the steering angular velocity deviation integrated value sum_ΔQ at 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).
[0097]
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).
[0098]
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.
[0099]
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).
[0100]
In S112, a target convergence current Ihd * (= Ihd1 * + Ihd2 * + Ihd3 *) obtained by synthesizing the PID control is obtained (processing of the adder 101).
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”, and if not (that is, if the vehicle is steered or steered), the gain η is “0”.
[0101]
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.
[0102]
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.
[0103]
As shown in FIG. 2, the adder 84 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 added and the motor current command value Io is output to the subtractor 33.
[0104]
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. Therefore, the adder 84 outputs an assist current command value I for MA-MT control to the subtractor 33 as a motor current command value Io.
[0105]
On the other hand, when the hand is lightly touching the steering wheel 1 or when it 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 for MA-MT control is not input to the adder 84. 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 subtracter 33 as the motor current command value Io.
[0106]
Thereafter, the CPU 21 drives and controls the motor 6 based on the motor current command value Io via the subtractor 33 and the current control unit 34. Therefore, even if the steering wheel 1 is released while being steered by a certain steering angle during traveling, an appropriate assist force of the motor 6 can be obtained from high speed to low speed by the convergence control.
[0107]
Therefore, according to the above embodiment, the following effects can be obtained.
(1) In the above embodiment, when the steering wheel 1 is lightly touched or released, the influence is received by the assist current command value I based on the MA-MT control, but is not affected by the steering torque Th. A target convergence current Ihd * based on the convergence control is added to the assist current command value I, and the motor 6 is driven and controlled by the motor current command value Io.
[0108]
For this reason, unlike the conventional case, even when letting go at low speed, the steering wheel 1 does not stop in the middle of movement due to internal friction in the electric power steering device, and the target steering angle θ * which is a substantially neutral position is satisfactorily achieved. The steering wheel 1 can be returned.
[0109]
On the other hand, even at high speed, the target convergence current Ihd * is added to the assist current command value I and the motor 6 is reliably driven and controlled. Thus, stable convergence can be provided without the steering wheel 1 overshooting.
[0110]
(2) In the above embodiment, the determination as to whether or not the target convergence current Ihd * is added to the assist current command value I is made based on the magnitude of the steering torque Th detected by the hand release determination unit 82. For this reason, when the hand release determination unit 82 does not perform the hand release determination, that is, when the value is sufficient to drive and control the motor 6 only with the assist current command value I during the turning steering, the target is unnecessarily generated. The convergence current Ihd * is not added. As a result, the auxiliary torque by the motor 6 decreases, and the steering wheel 1 does not feel heavy.
[0111]
On the other hand, the target convergence current Ihd * can be reliably added when the release is determined by the release release determination unit 82 when the steering wheel 1 is lightly touched or in the release state. Can be returned to the neutral position at a predetermined steering angular velocity Q.
[0112]
(3) In the above embodiment, in the convergence control, when the target convergence current setting unit 88 sets the target convergence current Ihd *, the second convergence current Ihd2 * calculated in the I control is changed to the P control. Is added to the first convergence current Ihd1 * set. Therefore, in the released state, the target steering is reliably performed without causing an offset between the target steering angular velocity Q * for returning the steering wheel 1 to the substantially neutral position and the actual steering angular velocity Q of the steering wheel 1. The actual steering angular velocity Q can be converged on Q * set by the angular velocity setting unit 87.
[0113]
(4) In the above embodiment, in the convergence control, when the target convergence current setting unit 88 sets the target convergence current Ihd *, the third convergence current Ihd3 * calculated in the D control is changed to the P control. Is added to the first convergence current Ihd1 * set. Accordingly, the target steering angular velocity Q * for returning the steering wheel 1 to the substantially neutral position in the released state is not delayed in response to the actual steering angular velocity Q of the steering wheel 1, and the actual steering angular velocity Q is The followability when converging to the target steering angular velocity Q * can be improved.
[0114]
(5) In the above embodiment, the second and third convergence currents Ihd2 * and Ihd3 * set by the I control and the D control are added to the first convergence current Ihd1 * set by the P control. Therefore, the target convergence current Ihd * having the effects (3) and (4) of the embodiment described above can be set.
[0115]
(6) In the above embodiment, the target steering angle θ is set by the target steering absolute angle setting unit 93 of the target steering angle setting unit 86 when the motor 6 is driven based on the convergence control when in the low-speed traveling state. * Is controlled to have a certain residual angle. Therefore, the rotation operation of the steering wheel 1 does not become unnatural as compared with the hydraulic power steering device.
[0116]
In addition, you may change each said embodiment into the following other examples.
In the above embodiment, in the convergence control, the target convergence current setting unit 88 of the convergence control unit 81 sets the target convergence current Ihd * obtained by combining so-called PID control, but at least only the P control is executed. The control or D control may not be executed. That is, when the D control is not executed, the target convergence current Ihd * is set by adding the first convergence current Ihd1 * set by the P control and the second convergence current Ihd2 * set by the I control. To do. Even if it does in this way, there exists an effect similar to (3) of the said embodiment.
[0117]
When the I control is not executed, the target convergence current Ihd * is set by adding the first convergence current Ihd1 * set by the P control and the third convergence current Ihd3 * set by the D control. To do. Even if it does in this way, there exists an effect similar to (4) of the said embodiment.
[0118]
In the above embodiment, the control device for the rack assist type electric power steering apparatus is configured to perform the MA-MT control. However, as shown in FIG. 15, the control apparatus for the column and pinion assist type electric power steering apparatus. It may be embodied in.
[0119]
In the figure, a speed reducer 5 is fixed to the steering shaft 2. A gear 7 attached to the rotating shaft of the motor 6 is engaged with the speed reducer 5. Further, a pinion shaft 8 is fixed to the speed reducer 5. Since other configurations have the same configurations as those of the first embodiment, detailed description thereof is omitted.
[0120]
In this aspect, the same configuration as the electrical configuration of the first embodiment is adopted, and only the method of determining the assist current command value I is different from that of the first embodiment. The method of determination will be described below.
[0121]
In the case of the column and pinion assist type, the rack thrust F at the time of the steering torque Th and the motor current Im is obtained by the following equation (E).
F (Th, Im) = 2π (Th + Kt · Im · G · ηg) · ηp / St (E) where Th is the steering torque, ηp is the rack and pinion gear efficiency, and St is the stroke ratio. Kt is a torque constant, G is a reduction ratio of the reducer 5, and ηg is a reducer efficiency of the reducer 5.
[0122]
Therefore, the rack thrust F at the time of the vehicle speed V, the target steering torque Th * at the steering angle θ, and the assist current command value I (hereinafter, this thrust is represented by F (Th *, I) using (E). ) And the rack thrust F at the time of the steering torque Th and the motor current Im (hereinafter, this thrust is represented by F (Th, Im)) is set to be equal to each other.
[0123]
Substituting the above equation (E) into F (Th *, I) = F (Th, Im) to obtain I, the following equation is obtained.
I = Im + (Th−Th *) / (Kt · G · ηg)
The assist current command value I thus obtained is output to the subtracter 33.
[0124]
When the assist current command value I is opposite in sign to the target steering torque Th *, that is, reverse assist, the assist current command value I is determined to be zero and output to the subtractor 33. Thereafter, the same processing as in the first embodiment is performed.
[0125]
In the above embodiment, the target steering absolute angle setting map of the target steering absolute angle setting unit 93 may be controlled so as to be corrected according to the road surface μ (dynamic friction coefficient of the road surface). That is, in the region where the road surface μ (the dynamic friction coefficient of the road surface) is low, the map is corrected as needed so that the target steering angle θ * set by the target steering angle setting unit 86 becomes large.
[0126]
Further, the target steering angular velocity setting map of the target steering angular velocity setting unit 87 in the above embodiment may be controlled to be corrected according to the road surface μ (the dynamic friction coefficient of the road surface). That is, in the region where the road surface μ (the dynamic friction coefficient of the road surface) is low, the map is corrected as needed so that the target steering angular velocity is reduced by Q *.
[0127]
By doing so, the target steering angle θ * or the target steering angular velocity Q * corresponding to the road surface μ (the dynamic friction coefficient of the road surface) is set, and the rotational operation of the steering wheel 1 is less than that of the hydraulic power steering device. Not natural. Further, only a change in friction in the electric power steering apparatus can be imparted with an unbiasedness regarding the convergence of the steering wheel 1.
[0128]
In the above embodiment, in the convergence control, the target steering angle θ * is controlled by the target steering absolute angle setting unit 93 so that the target steering angle θ * has a certain residual angle at low speed. It is also possible to control so that the steering wheel 1 is returned to the neutral position in any case regardless of whether the function of 93 is provided or not at high speed and low speed.
[0129]
In the above embodiment, the CPU 21 has the function of the hand release determination unit 82 to determine whether or not to add the target convergence current Ihd * to the assist current command value I, but has the function of the hand release determination unit 82. It may not be possible. Even in this way, it is possible to assist the steering wheel 1 in both the hand-released state and the steered state.
[0130]
In the above embodiment, the hand release determination unit 82 outputs “0” or “1” as the gain η. However, when the hand release is not detected, 0 <η instead of “0” as the gain η. A value of <1 may be output. In this way, unlike the first embodiment, instead of prohibiting the output of the convergence current, it can be output as a value suppressed to some extent.
[0131]
【The invention's effect】
As described above in detail, according to the first aspect of the present invention, when the steering torque is not detected or is very small, even if the assist current command value is not a sufficient value, the target convergence current that is not based on the steering torque is The motor current command value is set by addition. Accordingly, in the MA-MT control, unlike the conventional case, the steering wheel return characteristic can be improved during low-speed traveling, and the handle convergence can be improved during high-speed traveling.
[0132]
Addition In addition, since it is determined whether or not the output of the target convergence current is validated by the hand release determination means, the target convergence current is reliably output only when the assist current command value is insufficient.
[0133]
Claim 2 According to the invention of claim 1's In addition to the effect of the invention, the second steering current calculated based on the integral value of the deviation between the target steering angular velocity and the steering angular velocity is added to the first convergence current, thereby returning the target steering angular velocity for returning to the neutral position. The actual steering angular velocity can be surely converged to the target steering angular velocity set by the target steering angular velocity setting means without causing an offset between the actual steering angular velocity and the actual steering angular velocity.
[0134]
Claim 3 According to the invention of claim 1's In addition to the effect of the invention, the third steering current calculated based on the differential value of the deviation between the target steering angular velocity and the steering angular velocity is added to the first convergence current, thereby returning the target steering angular velocity for returning to the neutral position. However, the followability when the actual steering angular velocity converges to the target steering angular velocity can be improved without delaying the response to the actual steering angular velocity.
[0135]
Claim 4 According to the invention of claim 1's In addition to the effect of the invention, the effect of claim 3 and the effect of claim 4 can both be achieved.
Claim 5 According to the invention, claims 1 to 4 In addition to the effect of any one of the inventions, when the vehicle speed is low, the steering wheel is returned within the range of the remaining angle, so that it does not become unnatural compared to the hydraulic power steering device.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a control device for an electric power steering apparatus according to a first embodiment of the present invention.
FIG. 2 is a block diagram of the control device.
FIG. 3 is a flowchart of a target steering torque setting routine.
4 is a functional block diagram of the phase compensator 35. FIG.
FIG. 5 is also an explanatory diagram of a target steering torque setting map.
FIG. 6 is also an explanatory diagram of a dead zone.
FIG. 7 is a block diagram of a current command value calculation unit.
FIG. 8 is also an explanatory diagram of calculation of a dead zone width.
FIG. 9 is a block diagram of a convergence control unit.
FIG. 10 is a block diagram of a target steering angle setting unit.
FIG. 11 is a flowchart of a target steering angle calculation routine.
FIG. 12 is a flowchart of the same convergence control.
FIG. 13 is a flowchart of the same convergence control.
FIG. 14 is an explanatory diagram of hand release determination.
FIG. 15 is a schematic diagram of a control device according to an electric power steering device of another embodiment.
FIG. 16 is a schematic diagram of a control device according to a conventional electric power steering device.
[Explanation of symbols]
1 ... Steering wheel (handle), 6 ... Motor,
21 ... CPU (control means, target steering torque setting means, assist current calculation means, target steering angle setting means, target steering angular speed setting means, target convergence current setting means, release determination means),
31 ... Current command value calculation unit (assist current calculation means),
32 ... Target steering torque setting unit (target steering torque setting means),
81 ... Convergence control unit (target steering angle setting means, target steering angular speed setting means, target convergence current setting means)
86: Target steering angle setting unit (target steering angle setting means),
87: Target steering angular velocity setting unit (target steering angular velocity setting means),
88 ... target convergence current setting unit (target convergence current setting means),
82. Hand release determination unit (hand release determination means).

Claims (5)

In a control device for an electric power steering device provided with a control means for driving and controlling a motor based on a motor current command value,
Target steering torque setting means for setting a target steering torque based on the steering angle and the vehicle speed;
Assist current calculation means for calculating an assist current command value based on the steering torque, the target steering torque, and the motor current of the motor;
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;
A hand release determining means for determining whether to release the handle based on the steering torque ;
Based on the determination result of the hand release determination means, the output of the target convergence current of the target convergence current setting means is validated or suppressed, and added to the assist current command value to obtain a motor current command value. A control device for an electric power steering device. The target convergence current setting means calculates a first convergence current that is proportional to a deviation between the target steering angular velocity and the steering angular velocity, and further calculates a second convergence current based on an integrated value of the deviation between the target steering angular velocity and the steering angular velocity. 2. The control device for an electric power steering apparatus according to claim 1, wherein the target convergence current is set by adding the convergence current . The target convergence current setting means calculates a first convergence current proportional to the deviation between the target steering angular velocity and the steering angular velocity, and further calculates a third convergence current based on a differential value of the deviation between the target steering angular velocity and the steering angular velocity. 2. The control device for an electric power steering apparatus according to claim 1, wherein the target convergence current is set by adding the convergence current . The target convergence current setting means calculates a first convergence current that is proportional to a deviation between the target steering angular velocity and the steering angular velocity, calculates a second convergence current based on an integrated value of the deviation between the target steering angular velocity and the steering angular velocity, 2. The electric power steering apparatus according to claim 1, wherein a third convergent current is calculated based on a differential value between a steering angular velocity and a steering angular velocity, and a target convergent current is set by adding these convergent currents. Control device. The neutral position includes a predetermined residual angle range, and the target steering angle setting means sets the target steering angle so that the steering wheel is returned to the residual angle range when the vehicle speed is low. The control device for the electric power steering apparatus according to any one of claims 1 to 4 .

Images