WO2020183838A1 - Dispositif de direction de véhicule - Google Patents

Dispositif de direction de véhicule Download PDF

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Publication number
WO2020183838A1
WO2020183838A1 PCT/JP2019/049288 JP2019049288W WO2020183838A1 WO 2020183838 A1 WO2020183838 A1 WO 2020183838A1 JP 2019049288 W JP2019049288 W JP 2019049288W WO 2020183838 A1 WO2020183838 A1 WO 2020183838A1
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WIPO (PCT)
Prior art keywords
steering
unit
torque
angle
target
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PCT/JP2019/049288
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English (en)
Japanese (ja)
Inventor
貴弘 椿
浩保 熊谷
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日本精工株式会社
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Application filed by 日本精工株式会社 filed Critical 日本精工株式会社
Priority to JP2021505524A priority Critical patent/JPWO2020183838A1/ja
Publication of WO2020183838A1 publication Critical patent/WO2020183838A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits

Definitions

  • the present invention relates to a high-performance steering device for a vehicle that realizes a desired steering torque based on a torsion angle of a torsion bar or the like, is not affected by a road surface condition, and is not affected by changes in mechanical characteristics over time.
  • the electric power steering device which is one of the steering devices for vehicles, applies an assist force (steering assist force) to the steering system of the vehicle by the rotational force of the motor, and uses the power supplied from the inverter.
  • the driving force of the controlled motor is applied to the steering shaft or rack shaft as an assisting force by a transmission mechanism including a reduction mechanism.
  • feedback control of the motor current is performed in order to accurately generate an assist force.
  • the feedback control adjusts the motor applied voltage so that the difference between the steering assist command value (current command value) and the motor current detection value becomes small, and the adjustment of the motor applied voltage is generally PWM (pulse width). Modulation) Control duty is adjusted.
  • the column shaft (steering shaft, handle shaft) 2 of the handle 1 has a reduction mechanism 3, universal joints 4a and 4b, a pinion rack mechanism 5, and a tie rod 6a. It is further connected to the steering wheels 8L and 8R via the hub units 7a and 7b via 6b. Further, the column shaft 2 having the torsion bar is provided with a torque sensor 10 for detecting the steering torque Ts of the steering wheel 1 and a steering angle sensor 14 for detecting the steering angle ⁇ h, and is a motor that assists the steering force of the steering wheel 1. 20 is connected to the column shaft 2 via the reduction mechanism 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 via the ignition key 11.
  • the control unit 30 calculates the current command value of the assist (steering assistance) command based on the steering torque Ts detected by the torque sensor 10 and the vehicle speed Vs detected by the vehicle speed sensor 12, and compensates the current command value.
  • the current supplied to the EPS motor 20 is controlled by the voltage control command value Vref.
  • a CAN (Controller Area Network) 40 that exchanges various vehicle information is connected to the control unit 30, and the vehicle speed Vs can also be received from the CAN 40. Further, a non-CAN 41 that transmits / receives communications other than CAN 40, analog / digital signals, radio waves, etc. can also be connected to the control unit 30.
  • the control unit 30 is mainly composed of a CPU (including an MCU, an MPU, etc.), and FIG. 2 shows a general function executed by a program inside the CPU.
  • the steering torque Ts detected by the torque sensor 10 and the vehicle speed Vs detected by the vehicle speed sensor 12 are the current command value calculation unit. It is input to 31.
  • the current command value calculation unit 31 calculates the current command value Iref1, which is the control target value of the current supplied to the motor 20, by using the assist map or the like based on the input steering torque Ts and vehicle speed Vs.
  • Irefm-Im is calculated, and the deviation I is input to the PI (proportional integration) control unit 35 for improving the characteristics of the steering operation.
  • the voltage control command value Vref whose characteristics have been improved by the PI control unit 35 is input to the PWM control unit 36, and the motor 20 is PWM-driven via the inverter 37 as the drive unit.
  • the current value Im of the motor 20 is detected by the motor current detector 38 and fed back to the subtraction unit 32B.
  • the compensation signal CM from the compensation signal generation unit 34 is added to the addition unit 32A, and the characteristics of the steering system system are compensated by adding the compensation signal CM to improve the astringency, inertial characteristics, and the like. ..
  • the compensation signal generation unit 34 adds the self-aligning torque (SAT) 343 and the inertia 342 by the addition unit 344, further adds the convergence 341 to the addition result by the addition unit 345, and compensates the addition result of the addition unit 345. It is a signal CM.
  • the steering torque applied manually by the driver is detected by the torque sensor as the torsion torque of the torsion bar, and the assist current mainly corresponding to the torque is detected.
  • the motor current is controlled as.
  • the steering torque may differ depending on the steering angle due to the difference in the road surface condition (for example, inclination).
  • the steering torque may also be affected by variations in motor output characteristics due to aging.
  • Patent Document 1 an electric power steering device as shown in Japanese Patent No. 5208894 (Patent Document 1) has been proposed.
  • the steering angle or the steering torque determined based on the relationship between the steering angle or the steering torque and the response amount in order to give an appropriate steering torque based on the tactile characteristics of the driver.
  • the target value of steering torque is set based on the relationship (steering reaction force characteristic map).
  • the steering reaction force characteristic map must be obtained in advance, and control is performed based on the deviation between the target value of the steering torque and the detected steering torque. Therefore, there is a possibility that the influence on the steering torque remains.
  • the steering reaction force if the appropriate reaction force is not transmitted to the driver even when the vehicle is stopped and at extremely low speeds, the steering feeling will be felt without resistance, which may give the driver a sense of discomfort.
  • the present invention has been made based on the above circumstances, and an object of the present invention is not affected by the condition of the road surface, not affected by changes in the mechanical characteristics of the steering steering system over time, and with respect to the steering angle and the like. It is an object of the present invention to provide a steering device for a vehicle capable of easily achieving the same steering torque. Further, it is also an object to appropriately convey the steering reaction force at the time of stopping and at extremely low speed to the driver as a steering feeling.
  • the present invention relates to a vehicle steering device that includes at least a torsion bar having an arbitrary spring constant and a sensor that detects a torsion angle of the torsion bar, and assists and controls the steering system by driving and controlling a motor.
  • the object of the above is a target steering torque generating unit that generates a target steering torque, a conversion unit that converts the target steering torque into a target torsion angle, and a motor current that causes the torsion angle to follow the target torsion angle.
  • the target steering torque generating unit includes a torsion angle control unit that calculates a command value, and the target steering torque generating unit includes a steering characteristic correction unit that obtains a first torque signal based on a desired steering characteristic according to the steering angle. This is achieved by outputting the first torque signal as the target steering torque and driving and controlling the motor based on the motor current command value.
  • the stationary characteristic correction unit includes a stationary characteristic calculation unit that obtains a basic torque signal by performing hysteresis correction using the steering state and the steering angle, and obtains the basic torque signal.
  • the stationary characteristic correction unit further includes a vehicle speed-sensitive gain unit that calculates the first torque signal by outputting it as the first torque signal or by multiplying the basic torque signal by the vehicle speed-sensitive gain.
  • a basic map unit to be obtained and a damper calculation unit to obtain a third torque signal based on angular speed information using a damper gain map that is sensitive to vehicle speed are further provided, and the second torque signal and the third torque signal are included.
  • the target steering torque from at least one signal and the first torque signal, or because the basic map is sensitive to vehicle speed, or because the target steering torque generation unit is in front of the basic map unit.
  • a phase compensation unit that performs phase compensation is further provided in the subsequent stage, and the second torque signal is obtained from the steering angle and the vehicle speed via the basic map unit and the phase compensation unit, so that it is more effective. Achieved.
  • the torsion angle follows the target torsion angle by controlling the target torsion angle obtained based on the target steering torque generated by the target steering torque generating unit. It is possible to realize a desired steering torque and to provide an appropriate steering torque based on the driver's steering feeling.
  • the steering reaction force at the time of stopping and at extremely low speed can be appropriately transmitted to the driver as a steering feeling.
  • the present invention is a vehicle steering device for achieving the same steering torque with respect to the steering angle and the like without being affected by the road surface condition, and the torsion angle of the torsion bar and the like is set to a value according to the steering angle and the like.
  • the desired steering torque is realized by controlling so as to follow.
  • the steering angle ⁇ h is detected by a steering angle sensor provided on the upper part of the column shaft 2, and from the deviations of the steering wheel angle ⁇ 1 and the column angle ⁇ 2 , the torsion bar torsion angle ⁇ and torsion bar torque are determined by the following equations 1 and 2. Tt can be calculated. Kt is the spring constant of the torsion bar 2A.
  • the torsion bar torque Tt can also be detected using, for example, a torque sensor disclosed in Japanese Patent Application Laid-Open No. 2008-216172.
  • the torsion bar torque Tt is also treated as the steering torque Ts.
  • FIG. 4 is a block diagram showing a configuration example (first embodiment) of the present invention, in which the driver's steering wheel steering is assist-controlled by a motor in the EPS steering system / vehicle system 100.
  • the vehicle speed Vs and the right-turn or left-turn steering state STs output from the right-turn / left-turn determination unit 500 are input to the target steering torque generation unit 200 that outputs the target steering torque Tref.
  • the target steering torque Tref is converted into a target torsion angle ⁇ ref by the conversion unit 400, and the target torsion angle ⁇ ref is input to the torsion angle control unit 300 together with the torsion angle ⁇ of the torsion bar 2A and the motor angular velocity ⁇ m.
  • the twist angle control unit 300 calculates a motor current command value Imc so that the twist angle ⁇ becomes a target twist angle ⁇ ref, and the motor of the EPS is driven by the motor current command value Imcc.
  • FIG. 5 shows a configuration example of the target steering torque generation unit 200
  • the target steering torque generation unit 200 includes a basic map unit 210, a differentiation unit 220, a damper gain unit 230, a stationary characteristic correction unit 240, a multiplication unit 250, and an addition unit.
  • the steering angle ⁇ h is input to the basic map unit 210, the differential unit 220 and the stationary characteristic correction unit 240
  • the vehicle speed Vs is input to the basic map unit 210, the damper gain unit 230 and the stationary characteristic correction unit 240.
  • the steering state STs output from the right-turn / left-turn determination unit 500 are input to the stationary characteristic correction unit 240.
  • the basic map unit 210 has a basic map, and uses the basic map to output a torque signal (second torque signal) Tref_a having the vehicle speed Vs as a parameter as shown in FIG. That is, the torque signal Tref_a increases as the magnitude (absolute value)
  • the code unit 211 outputs the code (+1 or -1) of the steering angle ⁇ h to the multiplication unit 212.
  • the magnitude of the torque signal Tref_a is obtained from the magnitude of the steering angle ⁇ h by a map, and this is multiplied by the sign of the steering angle ⁇ h to calculate the torque signal Tref_a.
  • a map the code (+1 or -1) of the steering angle ⁇ h
  • the basic map unit 210 is composed of the map, the sign unit, and the multiplication unit that refer to the magnitude
  • the differentiation unit 220 differentiates the steering angle ⁇ h to calculate the steering angle velocity ⁇ h, which is the angular velocity information, and the steering angle velocity ⁇ h is input to the multiplication unit 250.
  • Damper gain unit 230 outputs the damper gain D G is multiplied by the steering angular speed [omega] h.
  • Steering angular velocity ⁇ h which is multiplied by the damper gain D G at multiplying unit 250 is input to the adder 252 as the torque signal (third torque signal) Tref_b.
  • Damper gain D G using the damper gain map of vehicle speed sensitive type having the damper gain unit 230 is determined according to the vehicle speed Vs.
  • the damper gain map has a characteristic that it gradually increases as the vehicle speed Vs increases, as shown in FIG. 7, for example.
  • the damper gain map may be variable according to the steering angle ⁇ h.
  • the damper gain unit 230 and the multiplication unit 250 constitute a damper calculation unit.
  • the stationary characteristic correction unit 240 has a torque that makes the steering torque characteristic (stationary characteristic) desired according to the steering angle ⁇ h in the stationary state in which the steering wheel is steered when the vehicle is stopped and in the steering at extremely low speed.
  • the signal (first torque signal) Tref_c is output.
  • FIG. 8 shows a configuration example of the stationary characteristic correction unit 240.
  • the stationary characteristic correction unit 240 includes a stationary characteristic calculation unit 241 and a vehicle speed sensitive gain unit 242.
  • the stationary characteristic calculation unit 241 calculates the torque signal (basic torque signal) Tref_s according to the following equation 3 based on the steering angle ⁇ h and the steering state STs in order to make the stationary characteristic a hysteresis characteristic.
  • x ⁇ h
  • y Tref_s
  • a> 1 c>
  • a hys is the hysteresis width.
  • the above number 4 can be derived by substituting x1 for x and y1 for y R and y L in the above number 3.
  • any positive number larger than 1 can be used as "a”.
  • the numbers 3 and 4 become the following numbers 5 and 6.
  • FIG. 9 shows an example of a diagram of the torque signal Tref_s. That is, the torque signal Tref_s from the stationary characteristic calculation unit 241 has a hysteresis characteristic such as the origin of 0 ⁇ L1 (thin line) ⁇ L2 (broken line) ⁇ L3 (thick line).
  • a hys which is a coefficient representing the output width of the hysteresis characteristic
  • c which is a coefficient representing roundness
  • the vehicle speed-sensitive gain unit 242 outputs the torque signal Tref_c by multiplying the torque signal Tref_s by the gain corresponding to the vehicle speed (vehicle speed-sensitive gain).
  • the vehicle speed sensitive gain is set so as to decrease as the vehicle speed Vs increases. For example, as shown in FIG. 10, when the vehicle speed Vs is 0 km / h (when the vehicle is stopped), the vehicle speed sensitive gain is set to 2.0 so that the magnitude of the torque signal Tref_s is 2 [Nm], and then the vehicle speed.
  • the vehicle speed sensitive gain decreases at a constant rate, and when the vehicle speed Vs reaches Vs1 (for example, 2 km / h), the decrease rate decreases, and when the vehicle speed Vs is Vs2 (for example, 6 km / h).
  • the vehicle speed sensitive gain is set to 0.
  • the value of the vehicle speed-sensitive gain when the vehicle speed Vs is 0 km / h may be other than 2.0, the rate at which the vehicle speed-sensitive gain decreases may change at multiple locations, and the change in vehicle speed-sensitive gain may be a linear change. It may be a curvilinear change.
  • the stationary characteristic calculation unit 241 gives the stationary characteristic a hysteresis property
  • the vehicle speed sensitive gain unit 242 makes the stationary characteristic vehicle speed sensitive, so that the torque signal Tref_c makes the stationary characteristic a desired characteristic. Is generated, and the torque signal Tref_c makes it possible to appropriately transmit the steering reaction force at the time of stopping and at extremely low speed to the driver as a steering feeling.
  • the vehicle speed sensitive gain unit 242 by varying the hysteresis width A hys according to the vehicle speed Vs, may be vehicle speed sensitive to ⁇ Ri characteristics. In this case, the vehicle speed-sensitive gain unit 242 becomes unnecessary.
  • the coefficient a may also be variable according to the vehicle speed Vs.
  • the stationary characteristic may be a characteristic other than the hysteresis characteristic.
  • the torque signals Tref_c, Tref_b and Tref_a are sequentially added by the addition units 252 and 251 and output as the target steering torque Tref.
  • the rudder angular velocity ⁇ h is obtained by a differential calculation with respect to the steering angle ⁇ h, but a low-pass filter (LPF) process is appropriately performed in order to reduce the influence of high-frequency noise. Further, the differential operation and the LPF processing may be performed by the high-pass filter (HPF) and the gain. Further, the steering angular velocity ⁇ h is calculated by performing differential calculation and LPF processing on the handle angle ⁇ 1 detected by the upper angle sensor or the column angle ⁇ 2 detected by the lower angle sensor instead of the steering angle ⁇ h. Is also good.
  • the motor angular velocity ⁇ m may be used as the angular velocity information instead of the steering angular velocity ⁇ h, and in this case, the differential unit 220 becomes unnecessary.
  • the conversion unit 400 has a characteristic of -1 / Kt in which the sign of the reciprocal of the spring constant Kt of the torsion bar 2A is inverted, and converts the target steering torque Tref into the target torsion angle ⁇ ref.
  • the twist angle control unit 300 calculates the motor current command value Imc based on the target twist angle ⁇ ref, the twist angle ⁇ , and the motor angular velocity ⁇ m.
  • FIG. 11 is a block diagram showing a configuration example of the torsion angle control unit 300, wherein the torsion angle control unit 300 includes a torsion angle feedback (FB) compensation unit 310, a torsion angular velocity calculation unit 320, a speed control unit 330, and a stabilization compensation unit. It includes 340, an output limiting unit 350, a subtracting unit 361, and an adding unit 362.
  • FB torsion angle feedback
  • the target torsional angle ⁇ ref output from the conversion unit 400 is additionally input to the subtracting unit 361, and the twisting angle ⁇ is subtracted and input to the subtracting unit 361. At the same time, it is input to the torsion angular velocity calculation unit 320, and the motor angular velocity ⁇ m is input to the stabilization compensation unit 340.
  • the twist angle FB compensation unit 310 multiplies the compensation value C FB (transfer function) by the deviation ⁇ 0 of the target twist angle ⁇ ref calculated by the subtraction unit 361 and the twist angle ⁇ , and the twist angle ⁇ ref is multiplied by the target twist angle ⁇ ref. Outputs the target torsional velocity ⁇ ref that follows.
  • the compensation value C FB may be a simple gain Kpp or a commonly used compensation value such as a PI control compensation value.
  • the target torsional velocity ⁇ ref is input to the speed control unit 330.
  • the twist angle FB compensation unit 310 and the speed control unit 330 make it possible to make the twist angle ⁇ follow the target twist angle ⁇ ref and realize a desired steering torque.
  • the torsion angular velocity calculation unit 320 calculates the torsion angular velocity ⁇ t by a differential calculation with respect to the torsion angle ⁇ , and the torsion angular velocity ⁇ t is input to the speed control unit 330.
  • a differential operation pseudo-differentiation by HPF and gain may be performed.
  • the torsion angular velocity ⁇ t may be calculated from another means or other than the torsion angle ⁇ and input to the velocity control unit 330.
  • the speed control unit 330 calculates the motor current command value Imca1 so that the torsion angular velocity ⁇ t follows the target torsional velocity ⁇ ref by IP control (proportional leading PI control).
  • the subtraction unit 333 calculates the difference ( ⁇ ref- ⁇ t) between the target torsional velocity ⁇ ref and the torsional angular velocity ⁇ t, integrates the difference with the integration unit 331 having the gain Kvi, and the integration result is additionally input to the subtraction unit 334.
  • the torsion angular velocity ⁇ t is also input to the proportional unit 332, is subjected to proportional processing by the gain Kvp, and is subtracted and input to the subtraction unit 334.
  • the subtraction result in the subtraction unit 334 is output as the motor current command value Imca1.
  • the speed control unit 330 is not an IP control, but a PI control, a P (proportional) control, a PID (proportional integral differential) control, a PI-D control (differential leading PID control), a model matching control, and a model reference.
  • the motor current command value Imca1 may be calculated by a commonly used control method such as control.
  • the stabilization compensation unit 340 has a compensation value Cs (transfer function), and calculates the motor current command value Imca2 from the motor angular velocity ⁇ m. If the gains of the torsion angle FB compensating unit 310 and the speed control unit 330 are increased in order to improve the followability and the disturbance characteristics, a high-frequency controlled oscillation phenomenon occurs. As a countermeasure, the transfer function (Cs) required for stabilizing the motor angular velocity ⁇ m is set in the stabilization compensation unit 340. As a result, it is possible to realize stabilization of the entire EPS control system.
  • the transfer function (Cs) of the stabilization compensation unit 340 for example, a first-order filter represented by the following equation 7 set by pseudo differentiation and gain using the structure of the first-order HPF is used.
  • K sta is a gain
  • fc is a cutoff frequency, and for example, 150 [Hz] is set as fc.
  • s is the Laplace operator.
  • a second-order filter, a fourth-order filter, or the like may be used as the transfer function.
  • the motor current command value Imca1 from the speed control unit 330 and the motor current command value Imca2 from the stabilization compensation unit 340 are added by the addition unit 362 and output as the motor current command value Imccb.
  • the output limiting unit 350 limits the upper and lower limits of the motor current command value Imccb and outputs the motor current command value Imcc.
  • the upper limit value and the lower limit value with respect to the motor current command value are set in advance, and when the input motor current command value Imccb is equal to or more than the upper limit value, the upper limit value is set, and when it is less than the lower limit value, the lower limit value In other cases, the motor current command value Imccb is output as the motor current command value Imcc.
  • the right-turn / left-turn determination unit 500 inputs the motor angular velocity ⁇ m, determines whether the steering is right-turn or left-turn based on the sign of the motor angular velocity ⁇ m, and sets the determination result as the steering state STs. Output to the target steering torque generation unit 200 (step S10).
  • the target steering torque generation unit 200 inputs the steering angle ⁇ h and the vehicle speed Vs together with the steering state STs, and generates the target steering torque Tref (step S20). An operation example of the target steering torque generation unit 200 will be described with reference to the flowchart of FIG.
  • the steering angle ⁇ h input to the target steering torque generation unit 200 is in the basic map unit 210, the differential unit 220 and the stationary characteristic correction unit 240, the steering state STs is in the stationary characteristic correction unit 240, and the vehicle speed Vs is in the basic map unit 210.
  • the basic map unit 210 generates a torque signal Tref_a corresponding to the steering angle ⁇ h and the vehicle speed Vs using the basic map shown in FIG. 6 and outputs the torque signal to the addition unit 251 (step S22).
  • Differentiating section 220 differentiates the steering angle ⁇ h outputs steering angular velocity [omega] h (step S23), damper gain unit 230 outputs the damper gain D G corresponding to the vehicle speed Vs by using the damper gain map shown in FIG 7 (step S24), the multiplication unit 250 calculates a torque signal Tref_b by multiplying the steering angular velocity ⁇ h and damper gain D G, and outputs the result to adding section 252 (step S25).
  • the stationary characteristic correction unit 240 the steering angle ⁇ h and the steering state STs are input to the stationary characteristic calculation unit 241 and the vehicle speed Vs is input to the vehicle speed sensitive gain unit 242.
  • the stationary characteristic calculation unit 241 performs hysteresis correction for the steering angle ⁇ h by switching the calculation according to the equation 5 and the equation 6 according to the steering state STs (step S26), generates the torque signal Tref_s, and responds to the vehicle speed. Output to the gain unit 242.
  • the vehicle speed-sensitive gain unit 242 determines the vehicle speed-sensitive gain according to the characteristics shown in FIG. 10 according to the vehicle speed Vs, multiplies the torque signal Tref_s, and outputs the torque signal Tref_c to the addition unit 252 (step S27).
  • the stationary characteristic calculation unit 241 presets and holds the hysteresis widths A hys , c, x1 and y1 in the equations 5 and 6, but b and b'are calculated in advance from the equation 6 and x1. And b and b'may be retained instead of y1.
  • the torque signals Tref_b and Tref_c are added by the addition unit 252
  • the torque signal Tref_a is added by the addition unit 251 to the addition result
  • the target steering torque Tref is calculated (step S28).
  • the target steering torque Tref generated by the target steering torque generation unit 200 is input to the conversion unit 400, and is converted into the target twist angle ⁇ ref by the conversion unit 400 (step S30).
  • the target twist angle ⁇ ref is input to the twist angle control unit 300.
  • the twist angle control unit 300 inputs the twist angle ⁇ and the motor angular velocity ⁇ m together with the target twist angle ⁇ ref, and calculates the motor current command value Imc (step S40). An operation example of the twist angle control unit 300 will be described with reference to the flowchart of FIG.
  • the target torsion angle ⁇ ref input to the torsion angle control unit 300 is input to the subtraction unit 361, the torsion angle ⁇ is input to the subtraction unit 361 and the torsional velocity calculation unit 320, and the motor angular velocity ⁇ m is input to the stabilization compensation unit 340 (step). S41).
  • the deviation ⁇ 0 is calculated by subtracting the twist angle ⁇ from the target twist angle ⁇ ref (step S42).
  • Deviation [Delta] [theta] 0 is input to the helix angle FB compensation unit 310, the twist angle FB compensation unit 310 compensates the deviation [Delta] [theta] 0 is multiplied by the compensation value C FB on the deviation [Delta] [theta] 0 (step S43), the target torsion angular velocity ⁇ ref Is output to the speed control unit 330.
  • the torsion angular velocity calculation unit 320 that has input the torsion angle ⁇ calculates the torsion angular velocity ⁇ t by a differential calculation with respect to the torsion angle ⁇ (step S44), and outputs the torsion angular velocity ⁇ t to the speed control unit 330.
  • the difference between the target torsional velocity ⁇ ref and the torsional angular velocity ⁇ t is calculated by the subtraction unit 333, and the difference is integrated (Kvi / s) by the integration unit 331 and additionally input to the subtraction unit 334 (step S45).
  • the torsion angular velocity ⁇ t is proportionally processed (Kvp) by the proportional unit 332, the proportional result is subtracted and input to the subtraction unit 334 (step S45), and the motor current command value Imca1 which is the subtraction result of the subtraction unit 334 is output and added. It is input to the unit 362.
  • the stabilization compensation unit 340 performs stabilization compensation on the input motor angular velocity ⁇ m using the transfer function Cs represented by Equation 7 (step S46), and the motor current command value Imca2 from the stabilization compensation unit 340. Is input to the addition unit 362.
  • the addition unit 362 adds the motor current command values Imca1 and Imca2 (step S47), and the motor current command value Imccb, which is the addition result, is input to the output limiting unit 350.
  • the output limiting unit 350 limits the upper and lower limit values of the motor current command value Imccb by the preset upper limit value and lower limit value (step S48), and outputs the motor current command value Imcc (step S49).
  • the motor is driven based on the motor current command value Imcc output from the torsion angle control unit 300, and current control is performed (step S50).
  • FIG. 16 is a conceptual diagram of a diagram showing how the steering angle ⁇ h and the target steering torque Tref change when the vehicle speed Vs is steered at 0 km / h (stationary state).
  • the characteristics of the basic map are that the torque signal Tref_a is proportional to the magnitude of the steering angle ⁇ h
  • is 90 deg, and the torque signal Tref_a is 2 Nm. and then, damper gain D G is set to zero.
  • the hysteresis characteristic of the stationary characteristic calculation unit 241 is the characteristic shown in FIG. 9, and the characteristic of the vehicle speed sensitive gain in the vehicle speed sensitive gain unit 242 is the characteristic shown in FIG. Therefore, substantially, FIG. 16 is a diagram based on a linear basic map and a hysteresis characteristic multiplied by a gain of 2.0.
  • the target steering torque is changed by the function of the stationary characteristic correction unit 240 as shown in FIG. It is possible to realize the diagram characteristics in.
  • the target steering torque generation unit 200 in the first embodiment includes a basic map unit 210, a damper calculation unit (damper gain unit 230 and multiplication unit 250), and a stationary characteristic correction unit 240, but realizes a desired stationary characteristic.
  • a configuration may be configured in which only the stationary characteristic correction unit 240 is provided, specializing only in the stationary characteristic correction unit 240.
  • FIG. 17 shows a configuration example (second embodiment) of the target steering torque generation unit in this case.
  • the torque signal Tref_c output from the stationary characteristic correction unit 240 is output as the target steering torque Tref.
  • the target steering torque generation unit may be configured by combining the basic map unit 210 or the damper calculation unit and the stationary characteristic correction unit 240.
  • the motor current command value Imc output from the torsion angle control unit in the first and second embodiments is referred to as a current command value calculated based on the steering torque in the conventional EPS (hereinafter, referred to as "assist current command value").
  • assist current command value May be added, for example, to the current command value Iref1 output from the current command value calculation unit 31 shown in FIG. 2, or the current command value Iref2 obtained by adding the compensation signal CM to the current command value Iref1.
  • FIG. 18 shows a configuration example (third embodiment) to which the above contents are applied to the first embodiment.
  • the assist control unit 700 includes a current command value calculation unit 31, a current command value calculation unit 31, a compensation signal generation unit 34, and an addition unit 32A.
  • the assist current command value Iac output from the assist control unit 700 (corresponding to the current command value Iref1 or Iref2 in FIG. 2) and the motor current command value Imcc output from the twist angle control unit 300 are added by the addition unit 710.
  • the current command value Ic which is the result of addition, is input to the current limiting unit 720, and the motor is driven based on the current command value Icm in which the maximum current is limited, and current control is performed.
  • the phase compensation unit 260 that performs phase compensation may be inserted in the front stage or the rear stage of the basic map unit 210. That is, the configuration of the region R surrounded by the broken line in FIG. 5 may be configured as shown in FIGS. 19A or 19B.
  • the phase compensation unit 260 when phase advance compensation is set as phase compensation and, for example, phase advance compensation is performed by a primary filter having a numerator cutoff frequency of 1.0 Hz and a denominator cutoff frequency of 1.3 Hz. A refreshing feel can be achieved.
  • the target steering torque generating unit is not limited to the above configuration as long as it has a configuration based on the steering angle.
  • the stabilization compensation unit may be omitted.
  • the output limiting unit can also be omitted.
  • the present invention is applied to the column type EPS in FIGS. 1 and 3, the present invention is not limited to the upstream type such as the column type, and can be applied to the downstream type EPS such as the rack and pinion. Further, by performing feedback control based on the target torsion angle, it can be applied to a steer-by-wire (SBW) reaction force device having at least a torsion bar (arbitrary spring constant) and a sensor for detecting the torsion angle.
  • SBW steer-by-wire
  • FIG. 20 is a diagram showing a configuration example of the SBW system corresponding to a general configuration of the electric power steering device shown in FIG.
  • the same components are designated by the same reference numerals, and detailed description thereof will be omitted.
  • the SBW system is a system that does not have an intermediate shaft that is mechanically coupled to the column shaft 2 by a universal joint 4a, and transmits the operation of the handle 1 to a steering mechanism composed of steering wheels 8L, 8R, etc. by an electric signal. ..
  • the SBW system includes a reaction force device 60 and a drive device 70, and a control unit (ECU) 50 controls both devices.
  • the reaction force device 60 detects the steering angle ⁇ h by the steering angle sensor 14, and at the same time, transmits the motion state of the vehicle transmitted from the steering wheels 8L and 8R to the driver as reaction force torque.
  • the reaction force torque is generated by the reaction force motor 61.
  • the SBW system to which the present invention is applied is a type that has a torsion bar, and the torque sensor 10 detects the steering torque Ts. To do. Further, the angle sensor 74 detects the motor angle ⁇ m of the reaction force motor 61.
  • the drive device 70 drives the drive motor 71 in accordance with the steering of the steering wheel 1 by the driver, applies the driving force to the pinion rack mechanism 5 via the gear 72, and operates the pinion rack mechanism 5 via the tie rods 6a and 6b. Steer the facing wheels 8L and 8R.
  • An angle sensor 73 is arranged in the vicinity of the pinion rack mechanism 5 to detect the steering angle ⁇ t of the steering wheels 8L and 8R.
  • the ECU 50 In order to coordinately control the reaction force device 60 and the drive device 70, the ECU 50 adds information such as steering angle ⁇ h and steering angle ⁇ t output from both devices, and based on vehicle speed Vs from the vehicle speed sensor 12 and the like.
  • the voltage control command value Vref1 that drives and controls the reaction force motor 61 and the voltage control command value Vref2 that drives and controls the drive motor 71 are generated.
  • FIG. 21 is a block diagram showing the configuration of the fourth embodiment.
  • the reaction force device is twisted by controlling the twist angle ⁇ (hereinafter referred to as “twist angle control”) and controlling the steering angle ⁇ t (hereinafter referred to as “turning angle control”). It is controlled by angle control, and the drive unit is controlled by steering angle control.
  • the drive device may be controlled by another control method.
  • the torsion angle ⁇ follows the target torsion angle ⁇ ref calculated through the target steering torque generating unit 200 and the conversion unit 400 using the steering angle ⁇ h and the like by the same configuration and operation as in the first embodiment. Control to do so.
  • the motor angle ⁇ m is detected by the angle sensor 74, and the motor angular velocity ⁇ m is calculated by differentiating the motor angle ⁇ m by the angular velocity calculation unit 951.
  • the steering angle ⁇ t is detected by the angle sensor 73.
  • the current control unit 130 includes the subtraction unit 32B, the PI control unit 35, and the PWM control shown in FIG.
  • the target steering angle generation unit 910 In the steering angle control, the target steering angle generation unit 910 generates a target steering angle ⁇ tref based on the steering angle ⁇ h, and the target steering angle ⁇ tref is input to the steering angle control unit 920 together with the steering angle ⁇ t.
  • the steering angle control unit 920 calculates the motor current command value Imct so that the steering angle ⁇ t becomes the target steering angle ⁇ tref. Then, based on the motor current command value Imct and the current value Imd of the drive motor 71 detected by the motor current detector 940, the current control unit 930 has the same configuration and operation as the current control unit 130, and the drive motor has the same configuration and operation.
  • the 71 is driven to control the current.
  • FIG. 22 shows a configuration example of the target steering angle generation unit 910.
  • the target steering angle generation unit 910 includes a limiting unit 931, a rate limiting unit 932, and a correction unit 933.
  • the limiting unit 931 limits the upper and lower limits of the steering angle ⁇ h and outputs the steering angle ⁇ h1. Similar to the limiting unit 256 in the SAT information correction unit 250 and the output limiting unit 350 in the torsion angle control unit 300, the upper limit value and the lower limit value for the steering angle ⁇ h are set in advance to limit.
  • the rate limiting unit 932 sets and limits the amount of change in the steering angle ⁇ h1 in order to avoid a sudden change in the steering angle, and outputs the steering angle ⁇ h2. For example, the difference from the steering angle ⁇ h1 one sample before is used as the change amount, and when the absolute value of the change amount is larger than a predetermined value (limit value), the steering angle is set so that the absolute value of the change amount becomes the limit value. ⁇ h1 is added or subtracted and output as the steering angle ⁇ h2, and if it is equal to or less than the limit value, the steering angle ⁇ h1 is output as it is as the steering angle ⁇ h2.
  • an upper limit value and a lower limit value may be set for the amount of change to limit the amount of change. You may want to limit the rate.
  • the correction unit 933 corrects the steering angle ⁇ h2 and outputs the target steering angle ⁇ tref. For example, using a map that defines the characteristics of the target steering angle ⁇ tref with respect to the magnitude
  • FIG. 23 shows a configuration example of the steering angle control unit 920.
  • the steering angle control unit 920 has the same configuration as the configuration example of the torsion angle control unit 300 shown in FIG. 11 excluding the stabilization compensation unit 340 and the addition unit 362, and has a target torsion angle ⁇ ref and a torsion.
  • the target steering angle ⁇ tref and steering angle ⁇ t are input instead of the angle ⁇ , and the steering angle feedback (FB) compensation unit 921, the steering angular velocity calculation unit 922, the speed control unit 923, the output limiting unit 926 and the subtraction unit 927 are input.
  • FB steering angle feedback
  • the same operation is performed with the same configurations as the torsion angle FB compensation unit 310, the torsion angular velocity calculation unit 320, the speed control unit 330, the output limiting unit 350, and the subtraction unit 361, respectively.
  • the angle sensor 73 detects the steering angle ⁇ t
  • the angle sensor 74 detects the motor angle ⁇ m (step S110)
  • the steering angle ⁇ t is the steering angle control unit 920
  • the motor angle ⁇ m is the angular velocity.
  • the angular velocity calculation unit 951 differentiates the motor angle ⁇ m to calculate the motor angular velocity ⁇ m, and outputs the motor angular velocity to the right / left turn determination unit 400 (step S120).
  • the target steering angle generation unit 910 inputs the steering angle ⁇ h, and the steering angle ⁇ h is input to the limiting unit 931.
  • the limiting unit 931 limits the upper and lower limit values of the steering angle ⁇ h by preset upper and lower limit values (step S180), and outputs the steering angle ⁇ h1 to the rate limiting unit 932.
  • the rate limiting unit 932 limits the amount of change in the steering angle ⁇ h1 by a preset limit value (step S190), and outputs the steering angle ⁇ h2 to the correction unit 933.
  • the correction unit 933 corrects the steering angle ⁇ h2 to obtain the target steering angle ⁇ tref (step S200), and outputs the steering angle ⁇ h2 to the steering angle control unit 920.
  • the steering angle control unit 920 which has input the steering angle ⁇ t and the target steering angle ⁇ tref, calculates the deviation ⁇ t 0 by subtracting the steering angle ⁇ t from the target steering angle ⁇ tref by the subtracting unit 927 (step). S210). Deviation Derutashitati 0 is input to the turning angle FB compensation unit 921, the turning angle FB compensation unit 921 compensates the deviation Derutashitati 0 by multiplying the compensation value to the deviation ⁇ t 0 (step S220), the target turning angular velocity The ⁇ tref is output to the speed control unit 923.
  • the steering angular velocity calculation unit 922 inputs the steering angle ⁇ t, calculates the steering angular velocity ⁇ tt by a differential calculation with respect to the steering angle ⁇ t (step S230), and outputs the steering angular velocity ⁇ tt to the speed control unit 923.
  • the speed control unit 923 calculates the motor current command value Imcta by IP control in the same manner as the speed control unit 330 (step S240), and outputs the motor current command value Imcta to the output limiting unit 926.
  • the output limiting unit 926 limits the upper and lower limit values of the motor current command value Imcta by the preset upper limit value and lower limit value (step S250), and outputs the motor current command value Imct as the motor current command value Imct (step S260).
  • the motor current command value Imct is input to the current control unit 930, and the current control unit 930 is based on the motor current command value Imct and the current value Imd of the drive motor 71 detected by the motor current detector 940. 71 is driven and current control is performed (step S270).
  • the speed control unit 923 in the steering angle control unit 920 is not the IP control but the PI control, the P control, the PID control, and the PI-D, like the speed control unit 330 in the twist angle control unit 300. Control and the like are feasible, and any of P, I, and D controls may be used, and follow-up control by the steering angle control unit 920 and the twist angle control unit 300 is generally used.
  • the control structure may be used.
  • one ECU 50 controls the reaction force device 60 and the drive device 70, but the ECU for the reaction force device 60 and the ECU for the drive device 70 are used, respectively. It may be provided. In this case, the ECUs transmit and receive data by communication.
  • the SBW system shown in FIG. 20 does not have a mechanical coupling between the reaction force device 60 and the drive device 70, but when an abnormality occurs in the system, the column shaft 2 and the steering mechanism are clutched or the like.
  • the present invention is also applicable to SBW systems provided with a mechanical torque transmission mechanism that mechanically couples with. In such an SBW system, when the system is normal, the clutch is turned off to open the mechanical torque transmission, and when the system is abnormal, the clutch is turned on to enable the mechanical torque transmission.
  • the twist angle control unit 300 in the first to fourth embodiments and the assist control unit 700 in the third embodiment directly calculate the motor current command value Imc and the assist current command value Iac. Before calculating them, the motor torque (target torque) to be output may be calculated first, and then the motor current command value and the assist current command value may be calculated. In this case, in order to obtain the motor current command value and the assist current command value from the motor torque, the generally used relationship between the motor current and the motor torque is used.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Steering Control In Accordance With Driving Conditions (AREA)
  • Power Steering Mechanism (AREA)

Abstract

Le problème selon la présente invention consiste à produire un dispositif de direction de véhicule qui permet d'atteindre facilement un couple de direction équivalent à un angle de direction, ou analogue, indépendamment de l'état d'une chaussée et sans être affecté par les changements des caractéristiques mécaniques d'un système de direction du fait du vieillissement. La présente invention aborde également le problème consistant à transmettre de manière appropriée une force de réaction de direction à un conducteur sous forme d'une sensation de direction lorsqu'un véhicule est arrêté ou se déplace à une vitesse très faible. La solution selon l'invention porte sur un dispositif de direction de véhicule qui réalise la commande d'assistance d'un système de direction, le dispositif comprenant : une unité de génération de couple de direction cible pour générer un couple de direction cible ; une unité de conversion pour convertir le couple de direction cible en un angle de torsion cible ; et une unité de commande d'angle de torsion qui calcule une valeur de commande de courant de moteur de sorte que l'angle de torsion est produit pour suivre l'angle de torsion. L'unité de génération de couple de direction cible est équipée d'une unité de correction de caractéristique de direction statique qui détermine un premier signal de couple sur la base de caractéristiques de direction statique souhaitées correspondant à l'angle de direction. Le premier signal de couple est délivré sous forme de couple de direction cible, et l'entraînement d'un moteur est commandé en fonction de la valeur de commande de courant de moteur.
PCT/JP2019/049288 2019-03-08 2019-12-17 Dispositif de direction de véhicule WO2020183838A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008168858A (ja) * 2007-01-15 2008-07-24 Jtekt Corp 電動パワーステアリング装置
JP2017056745A (ja) * 2015-09-14 2017-03-23 日立オートモティブシステムズ株式会社 パワーステアリング裝置
WO2018084190A1 (fr) * 2016-11-07 2018-05-11 日本精工株式会社 Appareil de direction à assistance électrique

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008168858A (ja) * 2007-01-15 2008-07-24 Jtekt Corp 電動パワーステアリング装置
JP2017056745A (ja) * 2015-09-14 2017-03-23 日立オートモティブシステムズ株式会社 パワーステアリング裝置
WO2018084190A1 (fr) * 2016-11-07 2018-05-11 日本精工株式会社 Appareil de direction à assistance électrique

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