JP2019098964A - Electric power steering device - Google Patents

Abstract

To provide an electric power steering device which achieves manual steering even if steering intervention is performed by a driver during automatic steering, more secures safety during emergency steering by the driver, and achieves both of assist control and steering angle control.SOLUTION: An electric power steering device includes: an assist control section which calculates an assist control current command value for assist control; a steering angle control section which calculates a steering angle control current command value for steering angle control; and a changeover determination/gradual change gain generation section which generates a gradual change gain for adjusting a control amount of the assist control and a control amount of the steering angle control. The steering angle control section has a position control section, a filter section, a steering angle speed control section, a steering intervention compensation section, and a steering wheel damping section. A steering angle control current command value is calculated by a basic steering angle control current command value, an intervention compensation steering angle control current command value, and a compensation steering angle control current command value. A current command value is calculated by an assist control current command value and a steering angle control current command value, which are adjusted by the gradual change gain.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an electric power steering apparatus that enables automatic steering by performing assist control and steering angle control on a steering system by drive control of a motor based on a current command value, and in particular, by a driver during automatic steering. The present invention relates to an electric power steering apparatus that is safe and can reduce discomfort even when steering intervention is performed.

  An electric power steering apparatus (EPS) that applies a steering assist force (assist torque) to a steering system of a vehicle by a rotational force of a motor is a drive force of the motor and a transmission mechanism such as a gear or a belt via a reduction mechanism. It is applied to the shaft or rack shaft as a steering assist force to perform assist control. Such a conventional electric power steering apparatus performs feedback control of motor current in order to generate assist torque accurately. The feedback control is to adjust the motor applied voltage so that the difference between the steering assist command value (current command value) and the motor current detection value becomes smaller, and the motor applied voltage is generally adjusted by PWM (pulse width It is performed by adjusting the duty of modulation) control.

  The general configuration of the electric power steering apparatus will be described with reference to FIG. 1. The column shaft (steering shaft, handle shaft) 2 of the steering wheel 1 is a reduction gear (worm gear) 3 constituting a reduction mechanism, universal joints 4a and 4b, Through the pinion rack mechanism 5 and the tie rods 6a and 6b, the steering wheels 8L and 8R are further connected via the hub units 7a and 7b. Further, a torsion bar is interposed on the column shaft 2, and a steering angle sensor 14 for detecting a steering angle θ of the steering wheel 1 by a torsion angle of the torsion bar and a torque sensor 10 for detecting a steering torque Tt are provided. A motor 20 for assisting the steering force of the steering wheel 1 is connected to the column shaft 2 via a reduction gear 3. Electric power is supplied from the battery 13 to the control unit (ECU) 30 that controls the electric power steering device, and an ignition key signal is input through the ignition key 11. The control unit 30 calculates the current command value of the assist control command on the basis of the steering torque Tt detected by the torque sensor 10 and the vehicle speed V detected by the vehicle speed sensor 12 to compensate the current command value. The current supplied to the motor 20 is controlled by the voltage control command value Vref.

  The steering angle sensor 14 is not essential and may not be provided, and it is also possible to obtain a steering angle from a rotation angle sensor such as a resolver connected to the motor 20.

  The control unit 30 is connected to a CAN (Controller Area Network) 40 that transmits and receives various information of the vehicle, and the vehicle speed V can also be received from the CAN 40. The control unit 30 can also be connected to a non-CAN 41 that transmits and receives communications other than the CAN 40, analog / digital signals, radio waves, and the like.

  The control unit 30 is mainly composed of a CPU (including an MPU, an MCU, etc.), and a typical function executed by a program inside the CPU is as shown in FIG.

  The control unit 30 will be described with reference to FIG. 2. The steering torque Tt detected by the torque sensor 10 and the vehicle speed V detected by the vehicle speed sensor 12 (or from the CAN 40) are current commands for calculating the current command value Iref1. The value is input to the value calculator 31. The current command value calculation unit 31 calculates a current command value Iref1, which is a control target value of the current supplied to the motor 20, using an assist map or the like based on the steering torque Tt and the vehicle speed V inputted. The current command value Iref1 is input to the current limiting unit 33 through the adding unit 32A, and the current command value Irefm whose maximum current is limited is input to the subtracting unit 32B, and a deviation I (= Irefm) from the feedback motor current Im. −Im) is calculated, and the deviation I is input to a PI (proportional integration) control unit 35 for improving the characteristics of the steering operation. The voltage control command value Vref whose characteristics are improved by the PI control unit 35 is input to the PWM control unit 36, and the motor 20 is PWM-driven through the inverter 37. The motor current Im of the motor 20 is detected by the motor current detector 38 and is fed back to the subtracting unit 32B. The inverter 37 is configured by a bridge circuit of FET as a semiconductor switching element.

  A rotation angle sensor 21 such as a resolver is connected to the motor 20, and the rotation angle θ is detected from the rotation angle sensor 21 and output.

  Further, the compensation signal CM from the compensation signal generation unit 34 is added to the addition unit 32A, and the characteristic compensation of the steering system is performed by the addition of the compensation signal CM to improve convergence and inertia characteristics. ing. The compensation signal generation unit 34 adds the self aligning torque (SAT) 34C and the inertia 34B in the addition unit 34D, adds the convergence 34A to the addition result in the addition unit 34E, and compensates the addition result of the addition unit 34E. It is assumed that the signal CM.

  In recent years, research and development of automatic driving technology of a vehicle has been advanced, and in automatic steering among them, proposals have been made to apply an electric power steering apparatus (EPS). When automatic steering is realized by EPS, a mechanism for assist control executed by the conventional EPS and a mechanism for steering angle control for controlling the steering system so that the vehicle travels in a desired direction are independent. It is common to have a configuration in which the output can be adjusted. Further, in steering angle control, position speed control is used which has excellent performance in response to a steering angle command, which is a control target for steering angle, and disturbance suppression to road surface reaction force, etc. In (proportional) control and speed control, PI (proportional integration) control is adopted.

  When performing assist control and steering angle control independently and switching the command value which is output from both and performing whole control, if it switches suddenly with a switch etc., the command value will fluctuate rapidly, and the steering wheel behavior May become unnatural and may give a sense of discomfort to the driver. In JP-A-2004-17881 (Patent Document 1), in order to cope with this problem, in switching between the torque control method (corresponding to assist control) and the rotation angle control method (corresponding to steering angle control), commands from both sides Each value is multiplied by a coefficient (the automation coefficient and the manual operation coefficient) and the added value is used as the final command value, and this coefficient is gradually changed to suppress a sudden change of the command value. Further, P control is used in position control in the rotation angle control method, and PI control is used in speed control.

  Japanese Patent No. 3917008 (Patent Document 2) automatically performs a hand operation according to a set steering angle, and in particular, an automatic steering control device for parking assistance is proposed. In this device, the torque control mode (corresponding to assist control) and the parking support mode (corresponding to steering angle control) can be switched. In the parking support mode, control is performed using parking data stored in advance. Is going. Then, P control is performed in the position control in the parking assistance mode, and PI control is performed in the speed control.

  Although patent 3912279 (patent document 3) does not apply EPS directly, when starting steering angle control by switching to automatic steering mode, it is made to increase steering speed (steering wheel angular velocity) gently. The driver's sense of discomfort due to sudden changes in the steering wheel at the start is reduced.

JP, 2004-17881, A Patent No. 3917008 gazette Patent No. 3912279 gazette

  However, in Patent Document 1, the command value for steering angle control (steering angle control command value) is limited by a coefficient during switching of the method and is output as the final command value, so the final command value is smaller by the limited amount. turn into. Due to this limitation, the actual speed of the motor is slower than the command value for the steering angular velocity calculated from the steering angle control command value (steering angular velocity command value), so a deviation between the steering angular velocity command value and the actual speed As a result, the integral value of I (integral) control in the speed control is accumulated, and a larger steering angle control command value is output from the speed control. As a result, in a state where the coefficient by which the command value (assist control command value) for assist control is multiplied gradually increases, the limitation by the coefficient is relaxed, so the steering angle control command value becomes excessive as the coefficient increases. The steering wheel responds excessively to the steering angular velocity command value, which may cause the driver to feel discomfort or discomfort such as a stuck feeling.

  Moreover, in patent document 1, P control is used for position control, PI control is used for speed control, and when there exists manual intervention by a driver during steering angle control, steering angle control is a steering angle control command value It becomes difficult to steer manually until the switching operation from steering angle control to assist control is performed. In addition, there is a possibility that a temporal delay occurs due to the manual input detection or the switching operation, and the driver can not perform the steering intervention operation sufficiently.

  Patent Document 2 also performs steering angle control using P control for position control and PI control for speed control. When steering angle control is performed in a vehicle, disturbances and load conditions largely change due to changes in vehicle speed, friction, and road surface reaction force, etc., so the device must have a control configuration resistant to them. However, with the control configuration of the device described in Patent Document 2, for example, when the road surface reaction force changes or when the target steering angle rapidly changes, vibration occurs due to the natural vibration of the steering wheel mass and the spring by the torsion bar. The driver may feel it as a sense of discomfort or discomfort.

  In Patent Document 3, the steering angular velocity is gradually increased at the start of the steering angle control, but when it starts to increase, it continues to increase until it reaches the upper limit value of the steering angular velocity, so the integrated value of I control accumulates excessively . As a result, the steering angle control command value becomes an excessive value, and the steering wheel excessively reacts to the steering angular velocity command value, which may cause the driver to feel discomfort.

  The present invention has been made under the circumstances as described above, and it is an object of the present invention to realize manual steering even if steering intervention is performed by the driver during automatic steering, and safety at the time of emergency steering by the driver It is an object of the present invention to provide an electric power steering apparatus which has both assist control and steering angle control, which secures the above. In addition, it reduces discomfort and discomfort to the driver such as a feeling of getting stuck at the time of switching from automatic steering to manual steering, further suppresses the vibration of the steering wheel during automatic steering, and reduces the discomfort to the driver.

  The present invention relates to an electric power steering apparatus that drives a motor based on a current command value and performs assist control and steering angle control on a steering system by drive control of the motor, and the above object of the present invention is at least steering torque. And an assist control unit that calculates an assist control current command value for the assist control, and a steering angle control for the steering angle control based on at least the steering torque, the steering angle command value, and the actual steering angle. The steering angle control unit that calculates the current command value, and the switching determination / swing variation gain generation that generates the gradual change gain that adjusts the control amount of the assist control and the control amount of the steering angle control based on at least the steering torque. A steering control unit for calculating a steering angular velocity command value based on a deviation between the steering angle command value and the actual steering angle, and the steering angular velocity command A filter unit that converts the steering angle to an extended steering angular velocity command value using an FF filter; and a steering angular velocity control unit that calculates a basic steering angle control current command value based on the deviation between the extended steering angular velocity command value and the actual steering angular velocity; A steering intervention compensation unit for obtaining an intervention compensation steering angle control current command value for steering intervention compensation according to the steering torque, and a compensation steering angle control current command for damping the vibration of the steering wheel based on the steering torque The steering wheel control unit calculates the steering angle control current command value from the basic steering angle control current command value, the intervention compensating steering angle control current command value, and the compensation steering angle control current command value. This is achieved by calculating the current command value from the assist control current command value adjusted by the gradual change gain and the steering angle control current command value.

  The above object of the present invention is that the steering angle control unit further includes a steering wheel vibration removing unit for reducing a vibration frequency component included in the steering angle command value, and the steering angle command value with the vibration frequency component reduced A dead zone setting unit which makes the value within a predetermined range for the steering torque zero by inputting to the position control unit, or the steering intervention compensation unit, and a current command value operation amount for the steering torque A compensation map section having a steering intervention compensation map having a characteristic defined, and by determining the intervention compensation steering angle control current command value from the steering torque through the dead zone setting section and the compensation map section, or The steering intervention compensation map is changed according to the vehicle speed, or the steering intervention compensation unit further includes a steering intervention phase compensation unit that performs phase compensation on the steering torque. By determining the intervention compensation steering angle control current command value from the steering torque through the steering intervention phase compensation unit, the dead zone setting unit, and the compensation map unit, or the position control unit may perform the steering angle command Calculating the steering angular velocity command value by P control using the value and the actual steering angle, or the steering wheel damping unit multiplies the steering torque by a gain, and the gain is A phase compensation is performed on the multiplied steering torque, and a damping phase compensation unit that outputs the compensation steering angle control current command value, or the steering angular velocity control unit controls the extended steering angular velocity command. By calculating the basic steering angle control current command value by IP control using the value and the actual steering angular velocity, or with respect to the steering angle command value as the gradual change gain By including the steering angle command gradual change gain to be multiplied, or the steering angle control unit limits the steering angle command value by the limit value 1 set according to the steering angle command gradual change gain. Or the steering angle control unit is set according to the steering angle command gradual change gain with respect to the amount of change of the steering angle command value. By further including a variable rate limiting unit which limits by the limit value 2, or by including, as the gradual change gain, a speed command gradual change gain multiplied by the extended steering angular velocity command value, or The steering angle control unit may further include a speed command value variable limiting unit that limits the extended steering angular velocity command value by the limit value 3 set according to the speed command gradual change gain, or ,Previous By including a speed control gradual change gain to be multiplied by the signal calculated in the steering angular velocity control unit as the gradual change gain, or as the gradual change gain, the intervention compensation steering angle control current command value By including a steering intervention gradual change gain to be multiplied by the same, or by including a steering angle control output gradual change gain by which the steering angle control current command value is multiplied as the gradual change gain, or The steering angle control unit may further include a steering angle control current command value limiting unit that limits the steering angle control current command value by a preset limit value 4, or the gradual change gain By including an assist map gradual change gain multiplied by the assist map output current determined in the assist control unit, or as the gradual change gain. By including the assist control output gradual change gain to be multiplied by the preparative control current command value, it is more effectively achieved.

  According to the electric power steering apparatus according to the present invention, in steering angle control, compensation for steering intervention is performed, steering wheel vibration is suppressed by gain and phase compensation, and adjustment of the steering state is performed using the gradual change gain and the limiter. Since it is performed, it is possible to reduce discomfort even if there is steering intervention during automatic steering, and switch from automatic steering to manual steering with reduced discomfort, and also suppresses steering wheel vibration during automatic steering. can do.

It is a block diagram which shows the outline | summary of an electric-power-steering apparatus. It is a block diagram showing an example of composition of a control unit (ECU) of an electric power steering device. It is a block diagram showing an example of composition of the whole vehicle system concerning the present invention. It is a block diagram which shows the structural example of a switching determination / gradual change gain production | generation part. It is a block diagram which shows the structural example of a manual input determination part. It is a graph which shows the example of change of the gradual change gain according to a steering state. It is a block diagram showing an example of composition of a steering angle control part and a change part. It is a characteristic view showing an example of a limit value in a steering angle command value variable limiting part. It is a block diagram showing an example of composition of a position control part. It is a characteristic view showing an example of a limit value in speed command value variable limiting section. It is a block diagram which shows the structural example (1st Embodiment) of a steering angle speed control part. It is a block diagram showing an example of composition of a steering intervention compensation part. It is a characteristic view showing an example of setting of a dead zone to steering torque in a steering intervention compensation part. It is a characteristic view showing an example of a steering intervention compensation map. FIG. 6 is a characteristic diagram showing an example of change of the variable gain with respect to the vehicle speed. It is a block diagram showing an example of composition of a steering wheel damping part. It is a characteristic view showing an example of a limit value in a steering angle control current command value limiting part. It is a flowchart which shows the operation example of EPS side ECU. It is a flowchart which shows the operation example of a switching determination / gradual change gain production | generation part. It is a flowchart which shows a part of operation example (1st Embodiment) of a steering angle control part. It is a flowchart which shows a part of operation example (1st Embodiment) of a steering angle control part. It is a block diagram showing an example of a driver's steering model used by simulation. It is a graph which shows the example of the time response of the target angle in simulation concerning steering intervention compensation, an actual steering angle, and steering torque. It is a graph which shows the example of a change of the real steering angle and steering torque in the simulation regarding steering intervention compensation. It is a graph which shows the example of the time response of the target angle in simulation about a dead zone, an actual steering angle, and steering torque. It is a graph which shows the result of the time response of the steering torque in the simulation regarding a dead zone. It is a graph which shows the simulation result about the flattery nature to steering angle command value. FIG. 6 is a characteristic diagram showing an example of frequency characteristics from a steering angular velocity command value to an actual steering angular velocity in a simulation regarding an FF filter. It is a graph which shows the simulation result regarding FF filter. It is a graph which shows the example of change of the target steering angle speed at the time of steering state transfer, gradual change gain, and a limit value. It is a block diagram which shows the structural example (2nd Embodiment) of a steering angle speed control part. It is a block diagram which shows the structural example (3rd Embodiment) of a steering angle speed control part. It is a graph which shows the example of a change of the target steering angle speed at the time of steering state transfer, gradual change gain, and a limit value (4th Embodiment).

  The electric power steering apparatus (EPS) according to the present invention performs assist control, which is a function of a conventional EPS, and steering angle control that is necessary for automatic steering in automatic driving. The assist control and the steering angle control are respectively executed by the assist control unit and the steering angle control unit, and the current for driving and controlling the motor using the assist control current command value and the steering angle control current command value output from each unit Calculate the command value. In automatic steering (automatic steering state), both steering angle control and assist control are performed, and in manual steering (manual steering state) in which the driver is involved in steering, assist control is performed. Switching between automatic steering and manual steering is generally performed by a switching signal from a control unit (ECU) or the like mounted on the vehicle, but even when steering intervention occurs from the driver during automatic steering, In the present invention, manual input determination is performed so that automatic steering and manual steering switching can be performed using the determination result, and the steering angle control unit and the assist control unit are turned on. The switching operation is performed using the gradual change gain for the output data and the internal data. These switching determination and the generation of the gradual change gain are performed by the switching determination / slow variation gain generation unit. Further, processing with an FF filter is performed on the steering angular velocity command value, and steering angular velocity control is performed using the steering angular velocity command value (extended steering angular velocity command value) after processing. Thereby, the responsiveness at the time of steering angle control and steering intervention can be improved. Furthermore, in order to reduce the sense of incongruity caused by the steering intervention during the automatic steering, the steering intervention compensation according to the steering torque is performed. For example, the steering angle control current command value is compensated with a compensation value (intervention compensation steering angle control current command value) determined by the steering intervention compensation unit using a steering intervention compensation map prepared in advance. In the present invention, in order to suppress the vibration of the steering wheel during automatic steering, compensation by gain and phase compensation is performed based on the steering torque. By installing the steering wheel vibration removing unit, it is also possible to reduce the vibration frequency component of the steering wheel included in the steering angle command value.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, the entire vehicle system including the electric power steering apparatus according to the present invention will be described.

  FIG. 3 shows a configuration example (first embodiment) of the entire vehicle system according to the present invention, and an ECU (hereinafter referred to as "vehicle-side ECU") 100 mounted on a vehicle and an ECU (mounted on EPS) Hereinafter, the “EPS-side ECU” 200) and a plant 400 are included.

  The vehicle-side ECU 100 includes a vehicle state quantity detection unit 110, a switching command unit 120, a target trajectory calculation unit 130, and a vehicle motion control unit 140.

  Vehicle state quantity detection unit 110 outputs data detected from an on-vehicle camera, distance sensor, angular velocity sensor, acceleration sensor, etc. as vehicle state quantity Cv to switching instruction unit 120, target track calculation unit 130, and vehicle movement control unit 140. Do.

  The switching command unit 120 inputs a signal Sg for switching the operation mode from the button or switch provided on the dashboard or the like together with the vehicle state amount Cv, and outputs the switching signal SW to the EPS-side ECU 200. The operation mode includes an "assist control mode" and a "steering angle control mode". The "assist control mode" is a mode corresponding to manual steering, and the "steering angle control mode" is a mode corresponding to automatic steering. Based on the value of the signal Sg indicating the driver's intention, the operation mode is determined in consideration of the value of each data in the vehicle state amount Cv, and the determined operation mode is output as the switching signal SW.

  The target trajectory calculation unit 130 calculates the target trajectory Am according to the existing method based on the vehicle state amount Cv, and outputs the target trajectory Am to the vehicle motion control unit 140.

  The vehicle motion control unit 140 includes a steering angle command value generation unit 141, and the steering angle command value generation unit 141 is a steering angle command that is a control target value of the steering angle based on the target track Am and the vehicle state amount Cv. A value θref is generated and output to the EPS side ECU 200.

  The EPS side ECU 200 includes an EPS state quantity detection unit 210, a switching determination / gradient change gain generation unit 220, a steering angle control unit 300, an assist control unit 230, a switching unit 240, a current control / drive unit 250 and a motor current detector 38. Have.

  The EPS state quantity detection unit 210 receives signals from the angle sensor, the torque sensor, and the speed sensor, and detects an EPS state quantity. Specifically, the angle sensor detects the steering angle (the angle above the torsion bar) θh as the actual steering angle θr, the torque sensor detects the steering torque Tt, and the speed sensor detects the vehicle speed V. Further, the actual steering angular velocity ωr is calculated by performing a differential operation on the actual steering angle θr. The actual steering angle θr and the actual steering angular velocity ωr are input to the steering angle control unit 300, and the steering torque Tt is input to the switching determination / gradient gain generating unit 220, the steering angle control unit 300 and the assist control unit 230. The steering angle control unit 300 and the assist control unit 230 are input. A column steering angle (angle below the torsion bar) may be used as the actual steering angle θr, or a motor angle sensor (rotational angle sensor) may be provided, and the rotational angle of the motor may be the actual steering angle θr. Furthermore, the actual steering angle θr and the vehicle speed V may be detected by the vehicle side ECU 100 and transmitted to the EPS side ECU 200. Further, the actual steering angular velocity ωr may be calculated from the difference calculation of the rotation angle detected by the motor angle sensor and the gear ratio, or may be calculated from the difference calculation of the actual steering angle θr. A low pass filter (LPF) may be inserted in the final stage of the EPS state quantity detection unit 210 to reduce high frequency noise. In that case, the actual steering angular velocity ωr may be calculated by an HPF (high pass filter) and gain. .

  The switching determination / gradient gain generation unit 220 determines switching between automatic steering and manual steering based on the switching signal SW from the vehicle-side ECU 100 and the steering torque Tt, and determines the gradual gain based on the determination result. As the gradual change gain, steering angle control output gradual change gain Gfa1, speed control gradual change gain Gfa2, speed command gradual change gain Gfa3, steering angle command gradual change gain Gfa4, steering intervention gradual change gain Gfa5, assist control output gradual change gain Gft1 The assist map gradual change gain Gft2 is obtained, Gfa1 and Gft1 are input to the switching unit 240, Gfa2, Gfa3, Gfa4 and Gfa5 are input to the steering angle control unit 300, and Gft2 is input to the assist control unit 230. Details of the switching determination / gradient gain generating unit 220 will be described later.

  The steering angle control unit 300 performs steering angle control by using a steering angle command value θref, an actual steering angle θr, an actual steering angular velocity ωr, a steering torque Tt, a vehicle speed V, and gradual change gains Gfa2, Gfa3, The steering angle control current command value IrefP1 is calculated using Gfa4 and Gfa5. The steering angle control current command value IrefP1 is input to the switching unit 240. The actual steering angular velocity ωr may be calculated by the steering angle control unit 300 instead of the EPS state quantity detection unit 210. Details of the steering angle control unit 300 will be described later.

  The assist control unit 230 includes, for example, a current command value calculating unit 31, a current limiting unit 33, a compensation signal generating unit 34, and an adding unit 32A in the configuration example shown in FIG. Based on Tt and the vehicle speed V, an assist control current command value IrefT1 corresponding to the current command value Irefm in FIG. 2 is calculated using the assist map. However, unlike the configuration example of FIG. 2, the assist map gradual change gain Gft2 output from the switching determination / slow change gain generation unit 220 is input, and the output from the current command value calculation unit 31 (assist map output current) is input. The multiplication is performed, and the multiplication result is input to the addition unit 32A. Note that the current limiting unit 33 and / or the compensation signal generating unit 34 may not be provided.

  The switching unit 240 calculates the current command value Iref using the steering angle control current command value IrefP1, the assist control current command value IrefT1, and the gradual change gains Gfa1 and Gft1. Details of the switching unit 240 will be described later.

  Current control / drive unit 250 includes, for example, subtraction unit 32B, PI control unit 35, PWM control unit 36 and inverter 37 in the configuration example shown in FIG. 2, and detected by current command value Iref and motor current detector 38. The motor is driven and controlled by the same operation as the configuration example of FIG. 2 using the motor current Im.

  The plant 400 is a physical model of a control target simulating the characteristics of the driver and the EPS and the mechanical characteristics of the vehicle in the steering wheel steering, and includes a driver steering transmission characteristic 410 and a mechanical transmission characteristic 420. The mechanical system operates based on the steering wheel hand input torque Th generated by the driver's steering and the motor current Im from the EPS side ECU 200, thereby generating state information EV related to the vehicle and the EPS. Output status information EV. The vehicle state quantity detection unit 110 of the vehicle side ECU 100 and the EPS state quantity detection unit 210 of the EPS side ECU 200 respectively detect the vehicle state quantity Cv and the EPS state quantity from the state information EV. Since the steering wheel hand input torque Th is generated by the driver's steering according to the steering wheel steering angle θh in the state information EV, the driver steering transmission characteristic 410 outputs the steering wheel hand input torque Th.

  Next, the switching determination / gradient gain generating unit 220, the steering angle control unit 300, and the switching unit 240 of the EPS side ECU 200 will be described in detail.

  FIG. 4 shows a configuration example of the switching determination / slow change gain generation unit 220. The switching determination / slow change gain generation unit 220 includes a switching determination unit 221 and a gradual change gain generation unit 222. An input determination unit 223 and a steering state determination unit 224 are provided.

  The manual input determination unit 223 determines the presence or absence of manual input using the steering torque Tt. A configuration example of the manual input determination unit 223 is shown in FIG. 5, and the manual input determination unit 223 includes a smoothing filter unit 225, an absolute value conversion unit 226, and a determination processing unit 227. The smoothing filter unit 225 has a smoothing filter, smoothes the steering torque Tt by the smoothing filter, and outputs the smoothed steering torque Tt '. The steering torque Tt 'is input to the absolute value converting unit 226, and the absolute value converting unit 226 outputs an absolute value (absolute value data) | Tt' | of the steering torque Tt '. The absolute value | Tt ′ | is input to the determination processing unit 227. The determination processing unit 227 compares a predetermined threshold Tth with the absolute value | Tt '|, and if the absolute value | Tt' | is greater than or equal to the threshold Tth, determines that “manual input is present”, and the absolute value | Is less than the threshold Tth, it is determined that "no manual input", and the determination result is output as a manual input determination signal Jh.

  The steering state determination unit 224 determines the steering state from the switching signal SW from the vehicle side ECU 100 and the manual input determination signal Jh. If the switching signal SW is in the "assist control mode" or the manual input determination signal Jh is "with manual input", the steering state is determined to be "manual steering". If not, that is, the switching signal SW is "steered When it is the angle control mode and the manual input determination signal Jh is "no manual input", it is determined that the steering state is "automatic steering". The determination result is output as a steering state determination signal Js. The steering state may be determined from only the manual input determination signal Jh. That is, when the manual input determination signal Jh is "with manual input", it is determined that the steering state is "manual steering", and when the manual input determination signal Jh is "without manual input", the steering state is "automatic steering". It may be determined that

  The gradual change gain generation unit 222 determines a gradual change gain based on the steering state determination signal Js. The gradual change gain takes different values depending on the steering state, and the steering state is determined by the steering state determination signal Js.

  The gradual change gains Gfa1, Gfa2, Gfa3, Gfa4 and Gfa5 are 100% in the automatic steering state and 0% in the manual steering state, and upon transition from the automatic steering state to the manual steering state and from the manual steering state to the automatic steering state The value changes gradually. For example, when transitioning from the automatic steering state to the manual steering state, the gradual change gains Gfa1 to Gfa5 change as shown in FIG. 6 (A). That is, when the steering state determination signal Js changes from "automatic steering" to "manual steering" at time t1, the gradual change gain successively decreases from that time, and becomes 0% at time t2. On the contrary, when transitioning from the manual steering state to the automatic steering state, the gradual change gain is successively increased from the time when the steering state determination signal Js changes to "automatic steering". If the value of the steering state determination signal Js changes while the gradual change gain is decreasing or increasing (hereinafter, this state is referred to as "switching state"), the gradual change gain is increasing if decreasing, if it is increasing. It turns to decrease. Although the gradual change gain in the switching state is changed linearly in FIG. 6A, it may be changed like an S-shaped curve in order to make the switching operation smooth, and changes linearly. The gradual change gain may be used by passing it through an LPF, for example, a first-order LPF whose cutoff frequency is 2 Hz. In addition, the gradual change gains Gfa1 to Gfa5 do not have to make the same change in conjunction with each other, but may make independent changes.

  The assist control output gradual change gain Gft1 is .alpha.t1 [%] (0.ltoreq..alpha.t1.ltoreq.150) in the automatic steering state, and 100% in the manual steering state, and as shown in FIG. As in the case of Gfa4, the value is gradually changed in the switching state.

  The assist map gradual change gain Gft2 is αt2 [%] (0 α αt2 150 150) in the automatic steering state and 100% in the manual steering state, and as shown in Fig. 6C, the gradual change gains Gfa1 to Gfa4 As in the case of, the value is gradually changed in the switching state.

  A configuration example of the steering angle control unit 300 and the switching unit 240 is shown in FIG. The steering angle control unit 300 includes a steering angle command value variable limiting unit 310, a variable rate limiting unit 320, a steering wheel vibration removing unit 330, a position control unit 340, a steering intervention compensating unit 350, a filter unit 355, and a speed command value variable limiting unit 360. , A steering angle control unit 370, a steering wheel damping unit 380, a steering angle control current command value limiting unit 390, multiplication units 391, 392 and 393, and addition units 394 and 395. The switching unit 240 includes multiplication units 241 and 242 and The adding unit 243 is provided.

  The steering angle command value variable limiting unit 310 of the steering angle control unit 300 is configured to steer an abnormal value or an excessive value due to a communication error or the like to the steering angle command value θref received from the vehicle side ECU 100 for automatic steering or the like. In order to prevent input to the angle control, a limit value (upper limit value, lower limit value) is set and limited, and is output as the steering angle command value θref1. In order to set an appropriate limit value in the automatic steering state and the manual steering state, the limit value is set in accordance with the steering angle command gradual change gain Gfa4. For example, as shown in FIG. 8, when the steering angle command gradual change gain Gfa4 is 100%, it is determined that the automatic steering state is set, and the steering angle command gradual change gain is limited by the limit value shown by the solid line. It is determined that the manual steering state is in the case where Gfa4 is 0%, and restriction is performed with a limit value whose absolute value is smaller than that in the automatic steering state as indicated by the broken line. When the steering angle command gradual change gain Gfa4 is between 0 and 100%, it is determined that the switching state is established, and the value between the solid line and the broken line is limited. In the switching state, the limit value may be limited by the limit value in the automatic steering state of the solid line or the limit value in the manual steering state of the broken line. The magnitude of the upper limit (absolute value) may be different from the magnitude of the lower limit.

  The variable rate limiting unit 320 controls the change amount of the steering angle command value θref1 in order to avoid the sudden change of the steering angle control current command value which is the output of the steering angle control due to the sudden change of the steering angle command value θref. The limit value is set and limited, and the steering angle command value θref2 is output. For example, assuming that the difference from the steering angle command value θref1 one sample before is the amount of change, and the absolute value of the amount of change is larger than a predetermined value (limit value), the absolute value of the amount of change is the limit value. The steering angle command value θref1 is added / subtracted and output as the steering angle command value θref2. If the steering angle command value θref2 is less than the limit value, the steering angle command value θref1 is output as the steering angle command value θref2. As in the case of the steering angle command value variable limiting unit 310, in order to set an appropriate limiting value in the automatic steering state and the manual steering state, the limiting value is set according to the steering angle command gradual change gain Gfa4. The steering state is determined from the steering angle command gradual change gain Gfa4. In the automatic steering state, a predetermined limit value is set. In the manual steering state, the limit value is set to zero so that the steering angle command value θref2 becomes constant without changing. Make it In the switching state, an intermediate value between the two limit values is used, but the limit value in the automatic steering state or the limit value in the manual steering state may be used. The upper limit value and the lower limit value may be set to limit the change amount instead of setting the limit value to the absolute value of the change amount.

  The multiplication unit 391 multiplies the steering angle command value θref2 by the steering angle command gradual change gain Gfa4, and outputs the result as the steering angle command value θref3. As a result, the target steering angle θt output from the steering wheel vibration removing unit 330 described later in the switching state from the automatic steering state to the manual steering state can be approached to zero, and the steering angle control can be made to act in the neutral state.

  The steering wheel vibration removing unit 330 reduces the vibration frequency component included in the steering angle command value θref3. During automatic steering, when the steering angle command is changing, a frequency (about 10 Hz) component is generated in the steering angle command value θref3 that excites vibration due to the spring property of the torsion bar and the inertia moment of the steering wheel. The steering wheel vibration frequency component included in the steering angle command value θref3 is reduced by filtering with an LPF, a notch filter or the like or phase delay compensation, and a target steering angle θt is output. As the filter, any filter may be used if the gain of the steering wheel vibration frequency band is lowered and the ECU can be implemented. By installing a multiplication unit 391 for multiplying the steering angle command gradual change gain Gfa4 before the steering wheel vibration removal unit 330, it is possible to reduce the steering wheel vibration frequency component generated by the multiplication of the steering angle command gradual change gain Gfa4. . When the steering wheel vibration frequency component is minute, the steering wheel vibration removing unit 300 may be omitted.

  The position control unit 340 is a P (proportional) control based on a deviation between the target steering angle θt and the actual steering angle θr, to make the actual steering angle θr closer to the target steering angle θt (basic steering angular velocity command Value) Calculate ωrefa.

  A configuration example of the position control unit 340 is shown in FIG. The position control unit 340 includes a proportional gain unit 341 and a subtraction unit 342. The deviation θe (= θt−θr) between the target steering angle θt and the actual steering angle θr is determined by the subtraction unit 342, and the deviation θe is input to the proportional gain unit 341. The proportional gain unit 341 multiplies the deviation θe by the proportional gain Kpp to calculate the steering angular velocity command value ωrefa.

  The filter unit 355 has an FF (feed forward) filter, and the FF filter converts the steering angular velocity command value ωrefa into a steering angular velocity command value (extended steering angular velocity command value) ωref. By using the FF filter, the control band of the actual steering angular velocity ωr with respect to the steering angle command value ωrefa can be extended to the high frequency side, and the responsiveness of speed control as an inner loop of steering angle control can be improved. If the response of speed control is improved, the gain of position control (steering angle control) that is outside speed control and steering intervention compensation can be largely adjusted without overshooting, resulting in steering angle control. And response during steering intervention can be improved. As the FF filter, for example, a filter that performs phase lead compensation with the cutoff frequency of the numerator of 3 Hz and the cutoff frequency of the denominator of 5 Hz is used.

  The multiplying unit 392 multiplies the steering angular velocity command value ωref by the speed command gradual change gain Gfa3, and outputs the result as the steering angular velocity command value ωrefg. The speed command gradual change gain Gfa3 is used to realize smooth switching when switching from the manual steering state to the automatic steering state. The speed command gradual change gain Gfa3 changes in synchronization with the steering angle control output gradual change gain Gfa1 by which the steering angle control current command value IrefP1 is multiplied (the synchronization may not be complete synchronization).

  The speed command value variable limiting unit 360 sets and limits the steering angular velocity command value ωrefg with a limiting value (upper limit value, lower limit value), and outputs the target steering angular velocity ωt. The limit value is set according to the speed command gradual change gain Gfa3. For example, if the speed command gradual change gain Gfa3 is less than a predetermined threshold, the magnitude (absolute value) of the limit value is a small value as indicated by the broken line in FIG. 10, and the magnitude of the limit value is indicated by a solid line Increase the value to The predetermined threshold is an arbitrary value of the speed command gradual change gain Gfa3 in the switching state, and when Gfa3 is less than the predetermined threshold, the size of the limit value is fixed at a small value of the broken line and Gfa3 is the predetermined threshold. If exceeded, the size of the limit value may be gradually increased up to the solid line. Note that the size of the upper limit value and the size of the lower limit value may be different.

  The steering angular velocity control unit 370 receives the target steering angular velocity ωt, the actual steering angular velocity ωr, and the speed control gradual change gain Gfa2, and the steering angle control current command value (basic steering) such that the actual steering angular velocity ωr follows the target steering angular velocity ωt. Angle control current command value IrefW is calculated by IP control (proportional lead PI control).

  A configuration example of the steering angular velocity control unit 370 is shown in FIG. The steering angular velocity control unit 370 includes gain multiplication units 371 and 372, an integration unit 373, subtraction units 374 and 375, and a multiplication unit 376.

  The gain multiplication unit 371 multiplies the gain kvi by the deviation ωe (= ωt−ωr) of the target steering angular velocity ωt calculated by the subtraction unit 374 and the actual steering angular velocity ωr, and outputs an operation amount D1. The integration unit 373 integrates the operation amount D1 to calculate the control amount Ir1. The multiplication unit 376 multiplies the control amount Ir1 by the speed control gradual change gain Gfa2, and outputs the result as a control amount Ir3. The multiplication of the speed control gradual change gain Gfa2 is performed to realize a smooth switching between the manual steering state and the automatic steering state, thereby alleviating the influence of accumulation of integral values in the steering angular velocity control at the time of switching. be able to. The gain multiplication unit 372 multiplies the actual steering angular velocity ωr by the gain Kvp, and outputs the control amount Ir2. In subtraction section 375, the deviation (Ir3-Ir2) of control amounts Ir3 and Ir2 is calculated, and it is output as steering angle control current command value IrefW. Note that an arbitrary method can be used as the integration of the integration unit 373 as long as it is an integration method that can be implemented on implementation, and when using pseudo integration, it may be configured by a first-order delay transfer function and gain . Further, the speed control gradual change gain Gfa2 may be changed in synchronization with the steering angle control output gradual change gain Gfa1.

  It should be noted that although the rudder angular velocity control unit 370 uses IP control, a generally used control method may be used if the actual rudder angular velocity can be made to follow the target rudder angular velocity. . For example, PI control, two-degree-of-freedom PI control, model reference control, model matching control, robust control, or a control method in which a disturbance is estimated and a compensation unit that cancels the disturbance component may be used in part.

  The steering intervention compensation unit 350 calculates a steering angle control current command value (intervention compensation steering angle control current command value) IrefS1 for steering intervention compensation according to the steering torque Tt. By the function of the steering intervention compensation unit 350, a current command value can be generated in the direction of reducing the generation of steering torque, and steering intervention during automatic steering can be realized. In addition, the steering intervention compensation unit 350 can make the steering torque Tt have an appropriate feeling by performing the compensation and the phase compensation with the vehicle speed sensitive type steering intervention compensation map.

  A configuration example of the steering intervention compensation unit 350 is shown in FIG. The steering intervention compensation unit 350 includes a steering intervention phase compensation unit 351, a dead zone setting unit 352, a compensation map unit 353, and an integration unit 354.

  The steering intervention phase compensation unit 351 sets phase lead compensation as phase compensation, and converts the steering torque Tt into a steering torque Tt1. For example, phase lead compensation is performed with a first-order filter in which the cutoff frequency of the numerator is 1.0 Hz and the cutoff frequency of the denominator is 1.3 Hz. As a result, it is possible to improve the feeling of crispness and the feeling of being caught when steering suddenly or the like. The steering intervention phase compensation unit 351 can be omitted, for example, when cost is important.

  The dead zone setting unit 352 sets a dead zone with respect to the steering torque Tt1, and outputs it as a steering torque Tt2. For example, a dead zone as shown in FIG. 13 is set. That is, when the dead zone is not set, the steering torque Tt1 becomes the steering torque Tt2 as shown by the broken line, but by setting the dead zone in a section where the steering torque Tt1 is around zero, as shown by the solid line In the section, the value of the steering torque Tt2 is zero, and when the section is deviated, the steering torque Tt2 is changed in accordance with the steering torque Tt1 with the same inclination as the broken line. By setting such a dead zone, in the section, the current command value manipulated variable DIref output from the compensation map unit 353 described later also becomes zero, and the steering intervention compensation is not performed. That is, when steering intervention by the driver occurs, the steering torque is likely to rise to the threshold of the dead zone, and as a result, manual input determination can be performed at an early timing. Note that the sizes of the positive and negative thresholds of the dead zone may not be the same.

  The compensation map unit 353 has a steering intervention compensation map, and obtains the current command value manipulated variable DIref using the steering intervention compensation map. The steering intervention compensation map is a map that defines the characteristics of the current command value operation amount with respect to the steering torque, and changes according to the vehicle speed, so the current command value operation amount DIref is obtained from the steering torque Tt2 and the vehicle speed V. The steering intervention compensation map is adjusted by tuning, for example, as shown in FIG. 14, the current command value manipulated variable also increases as the steering torque increases, but decreases as the vehicle speed increases. Thus, the higher the vehicle speed, the heavier the feel. The assist map used by the assist control unit 230 also has a characteristic that the assist control current command value decreases as the vehicle speed increases. Therefore, when the driver intervenes in steering at high speed, the steering angular velocity command value and the assist The increase in control current command value is suppressed, and sudden steering is not possible, and safe steering is possible.

  Integral unit 354 integrates current command value manipulated variable DIref to calculate steering angle control current command value IrefS1.

  The steering intervention phase compensation unit 351 may be installed after the dead zone setting unit 352 or after the compensation map unit 353. Although the dead zone setting unit 352 needs to be installed in front of the compensation map unit 353, a map in which the dead zone setting unit 352 is eliminated and a dead zone is provided as a steering intervention compensation map (the output value in the setting section Even if a map that is zero is used, the same effect as described above can be obtained. Also, instead of the steering intervention compensation map, the steering torque Tt2 may be multiplied by the variable gain Ktp to obtain the current command value manipulated variable DIref. The variable gain Ktp is a vehicle speed sensitive gain that changes according to the vehicle speed V, and is adjusted by tuning. For example, as shown in FIG. 15, as the vehicle speed V increases, the variable gain Ktp is decreased. Thus, the higher the vehicle speed, the heavier the feel. Although the variable gain Ktp changes as a broken line in FIG. 15, it may change in a curvilinear manner.

  The multiplication unit 393 multiplies the steering intervention control variable command value IrefS1 by the steering intervention gradual change gain Gfa5, and outputs the result as the steering control command instruction value IrefS. The steering intervention gradual change gain Gfa5, like the speed command gradual change gain Gfa3, is used to realize smooth switching when switching from the manual steering state to the automatic steering state, and is synchronized with the steering angle control output gradual change gain Gfa1. Change (not necessarily perfect synchronization).

  The steering wheel damping portion 380 damps the vibration of the steering wheel based on the steering torque Tt which is a torsion bar torque signal. The steering wheel vibration removing unit 330 also has an effect on steering wheel vibration during automatic steering, but the steering wheel vibration damping unit 380 can further improve the effect. The steering wheel vibration control unit 380 suppresses steering wheel vibration by gain and phase compensation, and outputs a steering angle control current command value (compensated steering angle control current command value) IrefV that works in a direction to eliminate the torsion of the torsion bar. In addition, the steering wheel damping portion 380 works in the direction to reduce the twist angle, and also has the effect of reducing the sense of discomfort when the driver intervenes in manual input.

  A configuration example of the steering wheel damping portion 380 is shown in FIG. The steering wheel damping unit 380 includes a gain unit 381 and a damping phase compensation unit 382. The gain unit 381 multiplies the steering torque Tt by the gain Kv, and outputs the control amount Irv. Damping phase compensation unit 382 is formed of, for example, a first-order filter, and converts control amount Irv into steering angle control current command value IrefV. Instead of the first-order filter, a second or higher-order phase compensation filter may be used.

  In addition section 394, steering angle control current command value IrefS output from multiplication section 393 and steering angle control current command value IrefV output from steering wheel damping section 380 are added, and output as steering angle control current command value IrefSV. Ru. The steering angle control current command value IrefW is further added by the addition unit 395 to the steering angle control current command value IrefW output from the steering angular velocity control unit 370, and is output as the steering angle control current command value IrefP2.

  The steering angle control current command value limiting unit 390 sets and limits the steering angle control current command value IrefP2 with a limiting value (upper limit value, lower limit value) in order to prevent an excessive output, and the steering angle control current The command value IrefP1 is output. For example, as shown in FIG. 17, the upper limit value and the lower limit value are set to limit the steering angle control current command value IrefP2. The magnitude of the upper limit (absolute value) may be different from the magnitude of the lower limit.

  The switching unit 240 is configured of multiplication units 241 and 242 and an addition unit 243.

  The multiplication unit 241 of the switching unit 240 multiplies the steering angle control current command value IrefP1 output from the steering angle control unit 300 by the steering angle control output gradual change gain Gfa1 output from the switching determination / slow change gain generation unit 220. And is output as a steering angle control current command value IrefP. The steering angle control output gradual change gain Gfa1 is used to smoothly perform switching operation between the manual steering state and the automatic steering state, and to realize a sense of discomfort to the driver, safety, and the like. The multiplication unit 242 multiplies the assist control current command value IrefT1 output from the assist control unit 230 by the assist control output gradual change gain Gft1, and outputs the result as the assist control current command value IrefT. The assist control output gradual change gain Gft1 smoothly switches between the manual steering state and the automatic steering state, and is used to realize steering intervention by the driver during automatic driving. The adding unit 243 adds the steering angle control current command value IrefP and the assist control current command value IrefT, and outputs the result as a current command value Iref.

  The assist map gradual change gain Gft2 used in the aforementioned assist control unit 230 is also used for the same purpose as the assist control output gradual change gain Gft1. In the automatic steering state, as shown in FIGS. 6B and 6C, Gft1 is set to αt1, Gft2 is set to αt2, and αt1 and αt2 are adjusted to improve system stability and vibration. It is possible to suppress the occurrence of Further, as long as the stability of the system in the automatic steering state can be maintained, αt1 may be simply 0% and αt2 may be 100%. In this case, the assist control current command value IrefT becomes a zero command because αt1 is 0%, and the steering intervention can be realized even in a state where the assist control is eliminated.

  In such a configuration, an operation example of the EPS-side ECU 200 will be described with reference to the flowcharts of FIGS.

  When the operation starts, the EPS state quantity detection unit 210 detects the actual steering angle θr, the steering torque Tt, and the vehicle speed V (step S10), determines the actual steering angle θr to the steering angle control unit 300, and switches the steering torque Tt. The vehicle speed V is output to the steering angle control unit 300 and the assist control unit 230, respectively, to the gradual change gain generation unit 220, the steering angle control unit 300, and the assist control unit 230. Furthermore, the EPS state quantity detection unit 210 calculates the actual steering angular velocity ωr from the actual steering angle θr (step S20), and outputs it to the steering angle control unit 300.

  The switching determination / gradient gain generation unit 220 that has input the steering torque Tt also performs switching determination between automatic steering and manual steering based on the presence / absence of the input of the switching signal SW output from the vehicle side ECU 100, and based on the determination result The gradual change gain is determined (step S30), and the gradual change gains Gfa2, Gfa3, Gfa4 and Gfa5 are output to the steering angle control unit 300, Gft2 to the assist control unit 230, and Gfa1 and Gft1 to the switching unit 240, respectively. Details of the operation of the switching determination / gradient gain generation unit 220 will be described later.

  The steering angle control unit 300 controls the steering angle command value θref from the vehicle side ECU 100, the actual steering angle θr from the EPS state quantity detection unit 210, the actual steering angular velocity ωr, the steering torque Tt and the vehicle speed V, and the switching determination / slow change gain The gradual change gains Gfa2, Gfa3, Gfa4 and Gfa5 from the generation unit 220 are input, and the steering angle control current command value IrefP1 is calculated using them (step S40), and is output to the switching unit 240. Details of the operation of the steering angle control unit 300 will be described later.

  Assist control unit 230 receives steering torque Tt, vehicle speed V and assist map gradual change gain Gft2, and calculates assist map output current (current value) by the same operation as current command value calculation unit 31 shown in FIG. (Step S50). Then, the assist map output current is multiplied by the assist map gradual change gain Gft2 (step S60), and the multiplication result is the same as the operation of the adder 32A, the current limiter 33 and the compensation signal generator 34 shown in FIG. To calculate the assist control current command value IrefT1 (step S70), and output it to the switching unit 240.

  The switching unit 240 multiplies the steering angle control output gradual change gain Gfa1 by the multiplication unit 241 by the input steering angle control current command value IrefP1 (step S80), and adds the steering angle control current command value IrefP that is the multiplication result Output to the part 243. Further, the input assist control current command value IrefT1 is multiplied by the assist control output gradual change gain Gft1 in the multiplication unit 242 (step S90), and the assist control current command value IrefT that is the multiplication result is output to the addition unit 243. The adding unit 243 adds the steering angle control current command value IrefP and the assist control current command value IrefT (step S100), and outputs the current command value Iref which is the addition result to the current control / drive unit 250.

  Current control / drive unit 250 operates in the same manner as subtraction unit 32B, PI control unit 35, PWM control unit 36 and inverter 37 shown in FIG. 2 to detect the current command value Iref and the motor detected by motor current detector 38. Using the current Im, the motor current Im is controlled to follow the current command value Iref (step S110), and drive control of the motor is performed.

  Details of an operation example of the switching determination / gradient gain generation unit 220 will be described with reference to the flowchart of FIG. In the steering state determination unit 224, it is assumed that "manual steering" is set as the initial value in the steering state determination signal Js.

  The input steering torque Tt is input to the manual input determination unit 223 in the switching determination unit 221. The manual input determination unit 223 smoothes the steering torque Tt by the smoothing filter unit 225 (step S210), and obtains the absolute value | Tt ′ | of the steering torque Tt ′ after smoothing by the absolute value conversion unit 226 (step S220) . The absolute value | Tt ′ | is input to the determination processing unit 227. If the absolute value | Tt '| is greater than or equal to the threshold Tth (step S230), the determination processing unit 227 determines that “manual input is present” (step S240), and if the absolute value | Tt' | In step S230, it is determined that "no manual input is made" (step S250), and a manual input determination signal Jh that is the determination result is output to the steering state determination unit 224.

  The steering state determination unit 224 confirms the presence or absence of the input of the switching signal SW (step S260), and the switching signal SW is input, and the switching signal SW is “assist control mode” or the manual input determination signal Jh is “manual input If yes (step S270), the steering state determination signal Js is updated to "manual steering" (step S280), and if not (step S270), the steering state determination signal Js is updated to "automatic steering" (step S270) Step S290). When the switching signal SW is not input, the steering state determination signal Js is left as it is. The steering state determination signal Js is input to the gradual change gain generation unit 222.

  The gradual change gain generation unit 222 confirms the value of the steering state determination signal Js (step S300). When the steering state determination signal Js is "manual steering", each gradual change gain (Gfa1 to Gfa5, Gft1, Gft2) is transitioned to the value (0% for Gfa1 to Gfa5, 100% for Gft1 and Gft2) in the manual steering state (Step S310). When the steering state determination signal Js is "automatic steering", each gradual change gain is transited to a value (100% for Gfa1 to Gfa5, αt1 for Gft1 and αt2 for Gft2) in the automatic steering state (step S320).

  The details of the operation example of the steering angle control unit 300 will be described with reference to the flowcharts of FIGS. 20 and 21.

  The steering angle command value variable limiting unit 310 checks the value of the input steering angle command gradual change gain Gfa4 (step S410), and when Gfa4 is 0%, the limit value is set to "manual steering" shown in FIG. Limit value (step S420). If Gfa4 is 100%, the limit value for "automatic steering" shown in FIG. 8 is set (step S430). If Gfa4 is 0 to 100%, an intermediate value is a limit value. (Step S440). Then, using the set limit value, the steering angle command value θref input from the vehicle side ECU 100 is restricted (step S450), and the steering angle command value θref1 is output.

  The steering angle command value θref1 is input to the variable rate limiting unit 320 together with the steering angle command gradual change gain Gfa4 and the actual steering angle θr. The variable rate limiting unit 320 checks the value of the steering angle command gradual change gain Gfa4 (step S460). If Gfa4 is 0%, the limit value is set to zero (step S470), and the rudder one sample before is held. The value of the angle command value θref1 is made the value of the actual steering angle θr (step S471). Step S471 is a state where the value at the end of the previous steering angle control remains at the time when the steering angle control at which Gfa4 becomes larger than 0% is started, and using that value as it is, the sudden change of the steering angle command value Since there is a possibility that the steering wheel may suddenly change, it is a treatment for suppressing the sudden change by starting in a state in which the steering wheel coincides with the actual steering angle θr. When Gfa4 is 100%, the limit value is set to a predetermined value (step S480), and when Gfa4 is 0 to 100%, an intermediate value is set as the limit value (step S490). Then, the difference (amount of change) between the steering angle command value θref1 and the steering angle command value θref1 one sample before is calculated (step S500). If the absolute value of the change amount is larger than the limit value (step S510), the steering angle command value θref1 is added / subtracted so that the absolute value of the change amount becomes the limit value (step S520), and output as the steering angle command value θref2. (Step S530). If the absolute value of the change amount is equal to or less than the limit value (step S510), the steering angle command value θref1 is output as the steering angle command value θref2 as it is (step S530).

  The steering angle command value θref2 is multiplied by the steering angle command gradual change gain Gfa4 by the multiplication unit 391 (step S540), and is output as the steering angle command value θref3. The steering angle command value θref3 is input to the steering wheel vibration removal unit 330 .

  The steering wheel vibration removal unit 330 reduces the vibration frequency component with respect to the steering angle command value θref3 (step S550), and outputs the result to the position control unit 340 as the target steering angle θt.

  The target steering angle θt is additionally input to the subtracting unit 342 in the position control unit 340. The actual steering angle θr is subtracted and input to the subtracting unit 342, and the deviation θe between the target steering angle θt and the actual steering angle θr is obtained by the subtracting unit 342 (step S560). The deviation θe is input to the proportional gain unit 341, and the proportional gain unit 341 multiplies the deviation θe by the proportional gain Kpp to calculate the steering angular velocity command value ωrefa (step S570). The steering angular velocity command value ωrefa is input to the filter unit 355.

  The filter unit 355 converts the steering angular velocity command value ωrefa into the steering angular velocity command value ωref by the FF filter (step S580).

  The steering angular velocity command value ωref is multiplied by the speed command gradual change gain Gfa3 by the multiplication unit 392 (step S590), and is input to the speed command value variable limiting unit 360 as the steering angular velocity command value ωrefg.

  Speed command value variable limiting section 360 inputs speed command gradual change gain Gfa3 together with steering angular velocity command value ωrefg, and confirms the value of speed command gradual change gain Gfa3 (step S600). Then, if Gfa3 is less than the predetermined threshold, the limit value is set as the "Gfa3 small" limit value shown in FIG. 10 (step S610). If Gfa3 is equal to or more than the predetermined threshold, it is set as the "Gfa3 large" limit value ((step S610) Step S620). The steering angular velocity command value ωrefg is restricted using the set limiting value (step S630), and the target steering angular velocity ωt is output. The target steering angular velocity ωt is input to the steering angular velocity control unit 370.

  The steering angular velocity control unit 370 inputs the actual steering angular velocity ωr and the speed control gradual change gain Gfa2 together with the target steering angular velocity ωt. The target steering angular velocity ωt is added to the subtracting unit 374 and the actual steering angular velocity ωr is subtracted and input to the subtracting unit 374. The deviation ωe between the target steering angular velocity ωt and the actual steering angular velocity ωr is input to the gain multiplying unit 371 (step S640) ). The gain multiplication unit 371 multiplies the deviation ωe by the gain Kvi (step S650), and outputs the operation amount D1. The operation amount D1 is input to the integration unit 373. The integration unit 373 integrates the operation amount D1 to calculate the control amount Ir1 (step S660), and outputs the control amount Ir1 to the multiplication unit 376. The multiplication unit 376 multiplies the control amount Ir1 by the speed control gradual change gain Gfa2 (step S670), and outputs the control amount Ir3. The control amount Ir3 is additionally input to the subtraction unit 375. The actual steering angular velocity ωr is also input to the gain multiplication unit 372, and the gain multiplication unit 372 multiplies the actual steering angular velocity ωr by the gain Kvp (step S680), outputs the control amount Ir2, and the control amount Ir2 is a subtraction unit. The subtraction is input to 375. Subtraction unit 375 calculates the deviation between control amounts Ir3 and Ir2 (step S690), and outputs the result to addition unit 395 as steering angle control current command value IrefW.

  On the other hand, the steering intervention compensation unit 350 inputs the vehicle speed V and the steering torque Tt, and the vehicle speed V is input to the compensation map unit 352 and the steering torque Tt to the steering intervention phase compensation unit 351. The steering intervention phase compensation unit 351 converts the steering torque Tt into the steering torque Tt1 by phase compensation (step S700). The steering torque Tt1 is input to the dead zone setting unit 352, and the dead zone setting unit 352 sets the dead zone to the steering torque Tt1 according to the characteristic shown in FIG. 13 (step S705), and outputs it as a steering torque Tt2. The steering torque Tt2 is input to the compensation map unit 353 together with the vehicle speed V, and the compensation map unit 353 uses the steering intervention compensation map determined from the vehicle speed V based on the characteristics shown in FIG. The current command value manipulated variable DIref for the above is determined (step S710). The current command value operation amount DIref is input to the integration unit 354. The integration unit 354 integrates the current command value operation amount DIref to calculate the steering angle control current command value IrefS1 (step S720).

  The steering angle control current command value IrefS1 is multiplied by the steering intervention gradual change gain Gfa5 in the multiplication unit 393 (step S730), and is output as the steering angle control current command value IrefS. The steering angle control current command value IrefS is output to the addition unit 394 It is input.

  The steering torque Tt is also input to the steering wheel damping portion 380. In the steering wheel damping unit 380, the gain unit 381 multiplies the input steering torque Tt by the gain Kv (step S740), and outputs the control amount Irv. Control amount Irv is phase-compensated by damping phase compensation unit 382 (step S750), and is output as steering angle control current command value IrefV. The steering angle control current command value IrefV is input to the adding unit 394.

  The steering angle control current command values IrefS and IrefV input to the adding unit 394 are added (step S760), and are output to the adding unit 395 as the steering angle control current command value IrefSV.

  The steering angle control current command values IrefW and IrefSV input to the adding unit 395 are added (step S770), and are output as the steering angle control current command value IrefP2. The steering angle control current command value IrefP2 is input to the steering angle control current command value limiting unit 390. The order of addition of IrefS, IrefV and IrefW may be different from that described above.

  The steering angle control current command value limiting unit 390 limits the steering angle control current command value IrefP2 using the limit value of the characteristic shown in FIG. 17 and outputs the steering angle control current command value IrefP1 (step S780).

  The operation of the steering angle control unit 300 and the operation of the assist control unit 230 may be performed in reverse order or in parallel. In the operation of the steering angle control unit 300, the operation up to calculation of the steering angle control current command value IrefS input to the adding unit 394, the operation up to calculation of the steering angle control current command value IrefV, the steering angle input to the adding unit 395 The operation up to the calculation of the control current command value IrefW and the operation up to the calculation of the steering angle control current command value IrefSV may be performed in reverse order or in parallel.

  The effects of the present embodiment will be described based on simulation results.

In the simulation, a vehicle motion model and a driver's steering model are set as a plant model of the plant 400. As a vehicle movement model, for example, Masato Abe, “Motor Movement and Control”, Tokyo Denki University, Tokyo Denki University Press, September 20, 2009, 1st Edition, 2nd Edition, Chapter 3 (p. 49) For example, using the model shown in -105), Chapter 4 (p. 107-130) and Chapter 5 (p. 131-147), as a steering model, for example, Daisuke Yokoi, Master's dissertation On the evaluation of the steering feeling of a car considering the above, "Mie University Graduate School of Engineering, Doctoral Course, Mechanical Engineering, February 6, 2007 Reception, Chapter 2 (p.3-5), Chapter 3 (p.6) -9) The models shown in (references) may be used, but not limited to, other models may be used. The steering model used in this simulation is shown in FIG. 22 for reference. In FIG. 22, C _arm and C _palm are viscosity coefficients, K _arm and K _palm are spring constants, and I _arm is an arm inertia moment. The steering wheel steering angle θh output from the mechanical model (mechanical transmission characteristic) is input to the steering model (driver steering transmission characteristic), and the steering wheel hand input torque Th output from the steering model is output to the mechanical model. The target angle described in the reference is hereinafter referred to as a driver's target angle (steering target angle) θarm. Furthermore, in the reference, the mass system of the arm is added to the column inertia moment, but by setting the force applied from the palm to the steering wheel as the steering wheel input torque Th, between the palm angle and the steering angle θh The values of the acting spring constant K _palm and the viscosity coefficient C _palm have no problem even if the simulation is performed with sufficiently large values, which is the case in this simulation. Further, the followability of the motor current with respect to the current command value is sufficiently fast, the influence of the operation of the current control / drive unit 250 is minor, and the current command value = motor current. Furthermore, the vehicle speed V is constant.

  First, the effect of the steering intervention compensation will be described.

  The steering angle command value θref was fixed at 0 [deg], and a simulation of automatic steering when the driver's target angle θarm was input was performed. As a reference, FIG. 23 shows time responses of the actual steering angle θr and the steering torque Tt with respect to the time change of the driver's target angle θarm in a simulation in which the driver's steering model is considered under the same conditions. In FIG. 23, the vertical axis represents the angle [deg] and the steering torque [Nm], and the horizontal axis represents the time [sec], the thick solid line represents the driver's target angle θarm, and the thin solid line represents the actual steering angle (in this embodiment, the steering angle The steering angle) θr and the broken line indicate the steering torque Tt. In FIG. 23, the assist control output gradual change gain Gft1 is 0%, that is, the assist control is not effective. Further, FIG. 23 is an example of a simulation for explaining how the actual steering angle θr and the steering torque Tt change with respect to the change of the driver's target angle θarm.

  Regarding changes in the actual steering angle θr and the steering torque Tt when such a driver's target angle θarm is input, there is no steering intervention compensation and speed control is performed by PI control and steering intervention compensation is present. A comparison was made. In the former, for comparison with the present embodiment, the difference between the integration methods is determined with the assist control output gradual change gain Gft1 and the assist map gradual change gain Gft2 both being 100%. In the latter case, the assist control output gradual change gain Gft1 is set to 0%. Further, in the conventional prior art (for example, Patent Document 1), during the steering angle control before switching, the assist control command value is 0 [deg], but it is estimated that steering intervention is more difficult than in the former case. I omitted it.

  FIG. 24 shows the simulation result. The vertical axis represents the steering torque [Nm], the horizontal axis represents the actual steering angle [deg], and the broken line shows the case where there is no steering intervention compensation, and the solid line shows the case where there is steering intervention compensation. However, in the steering intervention compensation unit 350, the width of the dead zone is zero, and the steering intervention compensation map is a straight line from the origin.

  As indicated by the broken line in FIG. 24, when there is no steering intervention compensation, the actual steering angle θr is broken up to about 3 [deg], but the velocity deviation (steering By continuously accumulating the angular velocity command value and the actual steering angular velocity, the steering angle command value θref (= 0 [deg]) is finally forcibly returned, and further, an emergency of 15 [Nm] or more is realized. Steering torque is generated, which makes it difficult for the driver to steer.

  On the other hand, as shown by the solid line in FIG. 24, when there is steering intervention compensation, steering can be performed to 20 [deg], and the steering angle command value θ ref (= 0 [deg]) may be pulled back. Absent. This is obtained by multiplying the steering angle control current command value IrefW output from the steering angular velocity control unit 370 by the steering angle control current command value IrefS1 output from the steering intervention compensation unit 350 (more precisely, the steering intervention gradual change gain Gfa5 This is because the steering angle control current command value IrefS) is added, and the speed deviation of the steering angular velocity command value ωref and the actual steering angular velocity ωr in the steered state is balanced near zero. Thus, the function of the steering intervention compensation unit 350 makes it possible to realize steering intervention by the driver. In addition, by increasing the gain of the output from the steering intervention compensation unit 350, lighter steering can be realized.

  Next, the effect of the dead zone in the steering intervention compensation will be described.

  Assuming steering for emergency avoidance, simulation was performed by inputting the driver's target angle θarm as shown in FIG. In FIG. 25, as in FIG. 23, the vertical axis is angle [deg] and steering torque [Nm], the horizontal axis is time [sec], the thick solid line is the driver's target angle θarm, the thin solid line and the broken line are driving. The time response of the actual steering angle θr and the steering torque Tt with respect to the time change of the target angle θarm of the person is shown. As indicated by the thick solid line in FIG. 25, the driver's target angle θarm was raised from 0.5 [sec] and changed to 60 [deg].

  FIG. 26 shows the result of comparison between the case where the driver's target angle θarm is input and the dead zone is set with a threshold of 2.5 Nm as the positive or negative steering torque Tt1 and the case where there is no dead zone. The manual input determination unit 223 in the switching determination / gradient gain generation unit 220 is a smoothing filter unit configured by a series connection of a primary LPF with a cutoff frequency of 1.5 Hz and a primary LPF with 3.0 Hz. The steering torque Tt is smoothed at 225, and when the absolute value | Tt ′ | of the steering torque Tt ′ after smoothing becomes equal to or more than the threshold value Tth of 2 [Nm], it is determined that “manual input is present”.

  In FIG. 26, the vertical axis is steering torque [Nm], the horizontal axis is time [sec], the thick solid line is steering torque Tt when there is no dead zone, the broken line is steering torque Tt when there is a dead zone, and the dotted line is a dead zone. The steering torque Tt 'in one case and the thin solid line show the steering torque Tt' in the case where there is no dead zone. The portion enclosed by a circle in FIG. 26 is the point in time when the absolute value of the steering torque Tt 'becomes the threshold value Tth, and a dead zone is provided (dotted line) is about 0.7 [sec] and no dead zone (thin) In the solid line), it is determined that “manual input is present” at a timing of about 0.8 [sec], and it can be confirmed that the determination can be made earlier by about 0.1 [sec]. Therefore, determination can be performed more quickly by providing the dead zone.

  Next, in order to explain how the actual steering angle θr follows the steering angle command value θref, the followability of the steering angle command value θref and the effect of the FF filter of the filter unit 355 will be described. In the simulation to confirm this effect, there is no steering intervention by the driver (steering wheel hand input torque Th = 0 [Nm]) and no steering intervention compensation in order to confirm the characteristics of only steering angle control. did.

  FIG. 27 shows an example of a time response in which the steering angle command value θref is ramped from 0 [deg] to 100 [deg]. In FIG. 27, the vertical axis represents the steering angle [deg], the horizontal axis represents time [sec], and the dotted line represents the steering angle command value θref. The response of the target steering angle θt and the actual steering angle θr output from the steering wheel vibration eliminator 330 having a first-order LPF with a cutoff frequency of 2 Hz with respect to the steering angle command value θref is thin solid line and thick Indicated by a solid line. It can be seen from FIG. 27 that the target steering angle θt and the actual steering angle θr follow the steering angle command value θref.

  From the above description, it can be said that both steering intervention and steering angle tracking can be realized during automatic steering.

  In the simulation of the FF filter, first, the frequency characteristics from the steering angular velocity command value ωrefa to the actual steering angular velocity ωr are compared in the case where there is no FF filter and in the case where there is an FF filter. A simulation is performed using a filter that performs phase lead compensation with the cutoff frequency of the numerator of 3 Hz and the cutoff frequency of the denominator of 5 Hz as the FF filter, and using a gain of 1 when there is no FF filter. Did. The results are shown in FIG. 28A shows the gain characteristic, and FIG. 28B shows the phase characteristic. The thin solid line shows the case where there is no FF filter, and the thick solid line shows the case where there is an FF filter. Assuming that the response frequency (limit frequency) of the steering angular velocity control is attenuated to -3 dB, the gain is about 3 Hz without the FF filter (thin solid line) and about 5 Hz with the FF filter (thick solid line). The value is higher when there is an FF filter. Therefore, it can be confirmed that the response of the steering angular velocity control is improved by the FF filter.

  By using the FF filter, the proportional gain Kpp in the position control unit 340 of the steering angle control unit 300 can be increased, which has an effect of improving the response of the steering angle control. In order to confirm this effect, the simulation was performed while changing the simulation condition of the time response of the steering angle control shown in FIG. Specifically, the proportional gain Kpp is doubled, and by using a gain having a magnitude of 1 as the steering wheel vibration removing unit 330, the steering wheel vibration removing unit 330 is not provided. The time response under this condition is shown in FIG. FIG. 29 shows a time response in which the steering angle command value θref is ramped from 0 [deg] to 100 [deg], as in the case of FIG. 27, and the vertical axis is the steering angle [deg], The horizontal axis is time [sec], and the dotted line indicates the steering angle command value θref. For the steering angle command value θref, the time response when there is no FF filter is shown by a thin solid line, and the time response when there is an FF filter is shown by a thick solid line. FIG. 29B shows an enlarged view of a part of FIG. 29A so that the difference can be seen. From FIG. 29, the steering angle overshoots from about 2.1 sec to about 2.4 sec without the FF filter, but with the FF filter, the steering angle command value θref is followed without overshooting. Know that The improved response of the steering angular velocity control by the use of the FF filter makes it difficult to overshoot even when the proportional gain Kpp is increased. As a result, the response of the steering angle control can be improved. Similarly, the response to steering intervention can be improved.

  As an end of the description of the effect, there is a possibility that the integral value of I control is accumulated excessively due to the increase of the steering angular velocity at the start of the steering angle control, and the steering angle control command value may become excessive. I will explain the effect on

  FIG. 30 is a diagram showing temporal changes in the target steering angular velocity ωt, the gradual change gain, and the limit value in the speed command value variable limiting unit 360 when shifting from the manual steering state to the automatic steering state. Note that only Gfa1 is shown in FIG. 30 on the assumption that the speed control gradual change gain Gfa2 and the speed command gradual change gain Gfa3 change in synchronization with the steering angle control output gradual change gain Gfa1. The assist control output gradual change gain Gft1 and the assist map gradual change gain Gft2 are also shown as changes in Gft1 as a reference, assuming that the changes are synchronized with Gfa1. Further, the magnitude of the limit value in the speed command value variable limiting unit 360 is set to be fixed at a small value when Gfa3 is less than the predetermined threshold, and is set to gradually increase when Gfa3 is equal to or greater than the predetermined threshold.

  The steering angular velocity command value ωref is multiplied by the speed command gradual change gain Gfa3, and is further limited by the speed command value variable limiting unit 360 to be the target steering angular speed ωt. When the transition from the manual steering state to the automatic steering state is started, Gfa3 gradually increases from zero, and the target steering angular velocity ωt also gradually increases from zero. Thereafter, when the steering angular velocity command value ωrefg, which is an input to the speed command value variable limiting unit 360, reaches the limiting value (limiting value a) at time t10, the target steering angular velocity ωt becomes constant at the limiting value a, but Gfa3 Keep increasing. Then, when Gfa3 becomes a predetermined threshold at time t11, the limit value gradually increases, and the target steering angular velocity ωt also increases accordingly. When Gfa3 becomes 100% at time t12 and the limit value becomes the limit value b at time t13, the target steering angular velocity ωt changes within the limit value b. During time t10 to t13, the target steering angular velocity ωt is limited by the limit value a, and is further limited by multiplication of the speed control gradual change gain Gfa2 in the steering angular velocity control unit 370. Excessive accumulation of the integral value is suppressed, and the current command value as the steering angle control output that causes the driver to feel uncomfortable can be reduced. Further, after transition of the limit value is completed (that is, after time t13), the steering angular velocity command value ωref is not limited by the Gfa3 and the velocity command value variable limiting unit 360, and the signal in the steering angular velocity control unit 370 is not limited by Gfa2. Therefore, it is possible to shift to normal steering angle control.

  In addition, regarding the multiplication of the respective gradual change gains (Gfa1 to Gfa5, Gft1, Gft2) in the first embodiment, in the case where the cost is more important than the effect by the gradual change gain multiplication, etc., at least one multiplication is left and the later multiplication is performed. Is optional. In addition, each limiting unit (steering angle command value variable limiting unit, variable rate limiting unit, speed command value variable limiting unit, steering angle control current command value limiting unit) can be omitted in the same case or the like. When the steering angle command value variable limiting unit 310, the variable rate limiting unit 320, the multiplying unit 391, and the steering wheel vibration removing unit 330 are omitted, the steering angle command value θref is input to the position control unit 340 as the target steering angle θt. It will be When the multiplying unit 392 and the speed command value variable limiting unit 360 are omitted, the steering angular velocity command value ωref is input to the steering angular velocity control unit 360 as the target steering angular velocity ωt.

  Another embodiment of the present invention will be described.

  In the first embodiment, the multiplication of the speed control gradual change gain Gfa2 in the steering angular velocity control unit 370 is performed on the control amount Ir1 which is the output from the integration unit 373 but the output from the subtraction unit 375 It is also possible to perform for a certain steering angle control current command value IrefW.

  FIG. 31 is a configuration example (second embodiment) of the steering angular velocity control unit in the case where the steering angle control current command value IrefW is multiplied by the speed control gradual change gain Gfa2. Compared with the steering angular velocity control unit 370 in the first embodiment shown in FIG. 11, in the steering angular velocity control unit 470 in the second embodiment, the multiplication unit 376 is not after the integration unit 373 but after the subtraction unit 375 It is installed and the other configuration is the same.

  In the operation example of the steering wheel angular velocity control unit 470 in the second embodiment, in the operation example of the first embodiment shown in FIG. 21, the integration unit 373 integrates the operation amount D1 to calculate the control amount Ir1 up to step S660. Is the same operation, and thereafter, the control amount Ir1 is input to the subtractor 375, and the subtractor 375 calculates the control amount Ir3 ′ as the deviation (Ir1−Ir2) between the control amount Ir1 and Ir2. The multiplying unit 376 multiplies the control amount Ir3 'by the speed control gradual change gain Gfa2, and outputs the result to the adding unit 394 as a steering angle control current command value IrefW. The subsequent steps (step S700 and subsequent steps) are the same operations as in the first embodiment.

  It is also possible to perform multiplication of the speed control gradual change gain Gfa2 at another point in the steering angular velocity control unit 370.

  In the configuration example (third embodiment) of the steering angular velocity control unit shown in FIG. 32, the speed control gradual change gain Gfa2 is multiplied by the deviation ωe that is the output from the subtraction unit 374. Compared with the rudder angular velocity control unit 370 in the first embodiment shown in FIG. 11, in the rudder angular velocity control unit 570 in the third embodiment, the multiplication unit 376 is not after the integration unit 373 but after the subtraction unit 374. It is installed and the other configuration is the same.

  In the operation example of the steering wheel angular velocity control unit 570 in the third embodiment, in the operation example of the first embodiment shown in FIG. 21, the subtraction unit 374 calculates the deviation ωe between the target steering angular velocity ωt and the actual steering angular velocity ωr The operation up to S640 is the same operation, and the deviation ωe is input not to the gain multiplication unit 371 but to the multiplication unit 376. The multiplication unit 376 multiplies the deviation ωe by the speed control gradual change gain Gfa2, and sets the deviation multiplication unit 371 as the deviation ωe1. Output. After that, the operation is the same as that of the first embodiment, except for step S670.

  In the above-described embodiments (first to third embodiments), the speed command value variable limiting unit 360 sets the limit value according to the speed command gradual change gain Gfa3, and limits when Gfa3 becomes a predetermined threshold value. Although the values are switched, the steering angle control output gradual change gain Gfa1 may be used instead of Gfa3 and the limit value may be switched when Gfa1 reaches 100%. In the configuration in this case (fourth embodiment), Gfa1 is input to the speed command value variable limiting unit instead of Gfa3, and the other configurations are the same as in the other embodiments. In the operation in the fourth embodiment, the determination operation (step S600 in FIG. 21) of the determination of the limit value in the speed command value variable limiting unit is only changed to confirmation whether Gfa1 is less than 100%. In the fourth embodiment, the time change of the target steering angular velocity ωt, the gradual change gain, and the limit value in the speed command value variable limiting unit when transitioning from the manual steering state to the automatic steering state is as shown in FIG. . Compared with the time change shown in FIG. 30, the limit value in the speed command value variable limiting unit gradually increases from time t12 when Gfa1 becomes 100%, and the target steering angular velocity ωt also increases accordingly There is.

1 Steering wheel 2 Column axis (steering shaft, steering wheel axis)
10 Torque sensor 12 Vehicle speed sensor 13 Battery 20 Motor 21 Rotation angle sensor 30 Control unit (ECU)
31 Current command value operation unit 33 Current limit unit 34 Compensation signal generation unit 35 PI control unit 36 PWM control unit 37 Inverter 38 Motor current detector 100 Vehicle side ECU
110 Vehicle state quantity detection unit 120 Switching command unit 130 Target trajectory calculation unit 140 Vehicle motion control unit 141 Steering angle command value generation unit 200 EPS side ECU
210 EPS state quantity detection unit 220 switching determination / gradient gain generation unit 221 switching determination unit 222 gradual variation gain generation unit 223 manual input determination unit 224 steering state determination unit 225 smoothing filter unit 226 absolute value conversion unit 227 determination processing unit 230 Assist control unit 240 switching unit 250 current control / drive unit 300 steering angle control unit 310 steering angle command value variable limiting unit 320 variable rate limiting unit 330 steering wheel vibration removing unit 340 position control unit 341 proportional gain unit 350 steering intervention compensating unit 351 steering Intervention phase compensation unit 352 Dead zone setting unit 353 Compensation map unit 354, 373 Integration unit 355 Filter unit 360 Speed command value variable limiting unit 370, 470, 570 Steering angular velocity control unit 371, 372 Gain multiplication unit 380 Steering wheel control unit 381 Gain unit 382 Vibration suppression phase compensation unit 390 Steering angle control current command value control Limit 400 plant

Claims (19)

In an electric power steering apparatus which drives a motor based on a current command value and performs assist control and steering angle control on a steering system by drive control of the motor,
An assist control unit that calculates an assist control current command value for the assist control based on at least a steering torque;
A steering angle control unit that calculates a steering angle control current command value for the steering angle control based on at least the steering torque, the steering angle command value, and the actual steering angle;
A switching determination / gradient gain generation unit that generates a gradual change gain for adjusting the control amount of the assist control and the control amount of the steering angle control based on at least the steering torque;
The steering angle control unit
A position control unit that calculates a steering angular velocity command value based on a deviation between the steering angle command value and the actual steering angle;
A filter unit for converting the steering angular velocity command value into an extended steering angular velocity command value using an FF filter;
A steering angular velocity control unit that calculates a basic steering angle control current command value based on a deviation between the extended steering angular velocity command value and an actual steering angular velocity;
A steering intervention compensator for obtaining an intervention compensation steering angle control current command value for steering intervention compensation according to the steering torque;
And a steering wheel damping unit for calculating a compensating steering angle control current command value for damping the steering wheel vibration based on the steering torque.
The steering angle control current command value is calculated from the basic steering angle control current command value, the intervention compensation steering angle control current command value, and the compensation steering angle control current command value,
An electric power steering apparatus, wherein the current command value is calculated from the assist control current command value adjusted by the gradual change gain and the steering angle control current command value. The steering angle control unit
And a steering wheel vibration removing unit for reducing a vibration frequency component included in the steering angle command value,
The electric power steering apparatus according to claim 1, wherein a steering angle command value obtained by reducing the vibration frequency component is input to the position control unit. The steering intervention compensation unit
A dead zone setting unit that sets a value within a predetermined range to zero with respect to the steering torque;
A compensation map unit having a steering intervention compensation map that defines characteristics of a current command value manipulated variable with respect to the steering torque;
The electric power steering apparatus according to claim 1 or 2, wherein the intervention compensation steering angle control current command value is obtained from the steering torque via the dead zone setting unit and the compensation map unit.   The electric power steering apparatus according to claim 3, wherein the steering intervention compensation map changes in accordance with a vehicle speed. The steering intervention compensation unit
And a steering intervention phase compensation unit that performs phase compensation on the steering torque,
The electric power steering apparatus according to claim 3 or 4, wherein the intervention compensation steering angle control current command value is obtained from the steering torque via the steering intervention phase compensation unit, the dead zone setting unit, and the compensation map unit.   The electric power steering apparatus according to any one of claims 1 to 5, wherein the position control unit calculates the steering angular velocity command value by P control using the steering angle command value and the actual steering angle. The handle vibration control unit is
A gain unit that multiplies the steering torque by a gain;
The electric power steering according to any one of claims 1 to 6, further comprising: a damping phase compensation unit that performs phase compensation on the steering torque multiplied by the gain and outputs the compensation steering angle control current command value. apparatus.   The motor according to any one of claims 1 to 7, wherein the steering angular velocity control unit calculates the basic steering angle control current command value by IP control using the extended steering angular velocity command value and the actual steering angular velocity. Power steering device.   The electric power steering apparatus according to any one of claims 1 to 8, wherein the gradual change gain includes a steering angle command gradual change gain to be multiplied with the steering angle command value. The steering angle control unit
10. The electric power steering apparatus according to claim 9, further comprising: a steering angle command value variable limiting unit that limits the steering angle command value by a limit value 1 set according to the steering angle command gradual change gain. . The steering angle control unit
The electric power according to claim 9 or 10, further comprising: a variable rate limiter configured to limit the amount of change of the steering angle command value by the limit value 2 set according to the steering angle command gradual change gain. Steering device.   The electric power steering apparatus according to any one of claims 1 to 11, wherein the gradual change gain includes a speed command gradual change gain to be multiplied with the extended steering angular velocity command value. The steering angle control unit
The electric power steering apparatus according to claim 12, further comprising a speed command value variable limiting unit that limits the extended steering angular velocity command value by a limit value 3 set according to the speed command gradual change gain.   The electric power steering apparatus according to any one of claims 1 to 13, wherein the gradual change gain includes a speed control gradual change gain to be multiplied by a signal calculated in the steering angular velocity control unit.   The electric power steering apparatus according to any one of claims 1 to 14, wherein the gradual change gain includes a steering intervention gradual change gain multiplied by the intervention compensation steering angle control current command value.   The electric power steering apparatus according to any one of claims 1 to 15, wherein the gradual change gain includes a steering angle control output gradual change gain to be multiplied with the steering angle control current command value. The steering angle control unit
The electric power steering apparatus according to any one of claims 1 to 16, further comprising a steering angle control current command value limiting unit for limiting the steering angle control current command value by a preset limit value 4.   The electric power steering apparatus according to any one of claims 1 to 17, wherein the gradual change gain includes an assist map gradual change gain which is multiplied by an assist map output current obtained in the assist control unit. The electric power steering apparatus according to any one of claims 1 to 18, wherein the gradual change gain includes an assist control output gradual change gain to be multiplied with the assist control current command value.