JP2017100673A - Steering control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose a use method of a plurality of new motors nonexistent so far.SOLUTION: An EPS3 (an automatic steering device 1) comprises a power imparting mechanism 30 comprising an angle control motor 33 and a torque control motor 34 for imparting power to a steering mechanism 10 comprising a steering wheel 11 capable of steering of a steered wheel 16. Such the EPS3 comprises a control part 31 for controlling driving of the angle control motor 33 by using an angle command value based on a rotation angle of the steering wheel 11 and controlling driving of the torque control motor 34 by using a torque command value based on steering torque inputted to the steering wheel 11. In a state of simultaneously driving the angle control motor 33 and the torque control motor 34, a maximum value of imparting torque of the torque control motor 34 is constituted so as to become larger than a maximum value of imparting torque of the angle control motor 33.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a steering control device.

2. Description of the Related Art Conventionally, in a vehicle steering apparatus, there is a plurality of motors that apply power to a steering mechanism and a steering control apparatus that controls each motor is disclosed in Patent Document 1.
Patent Document 1 discloses that a first system configured by combining a first motor and a first ECU and a second system configured by combining a second motor and a second ECU are disclosed. In the first system, the first ECU generates a torque command value by performing position control based on the steering position of the steering wheel and the position information of the first motor. The torque command value is distributed to the first system and the second system by the first ECU. Each ECU controls the driving of each motor based on the torque command value distributed by the first ECU.

JP 2004-182039 A

  In the said patent document 1, the power which steers a steered wheel is provided with respect to a common steering mechanism using each motor of two systems. The usage of each motor of these two systems is not limited to the usage of the above-mentioned Patent Document 1, but leaves room for proposal of new usage.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a steering control device capable of proposing new ways to use a plurality of motors.

  A steering control device that solves the above problem includes a first motor and a second motor that apply power to a steering mechanism that includes a steering wheel that enables turning of steered wheels. A power applying mechanism is provided. Such a steering control device controls the driving of the first motor using an angle command value based on the rotation angle of the steering wheel, and uses the torque command value based on the steering torque input to the steering wheel to control the second motor. The control part which controls the drive of is provided. In the situation where the first motor and the second motor are driven simultaneously, the maximum value of the power that the second motor driven using the torque command value applies to the steering mechanism is the angle command value. The first motor driven by using the motor is configured to be larger than the maximum value of the power applied to the steering mechanism.

  For example, depending on the second motor driven using a torque command value based on the steering torque input to the steering wheel, the user's intention can be reflected as power in the steering mechanism. During emergency steering such as avoiding obstacles while the vehicle is running, it is often necessary to apply a large power to the steering mechanism relative to the steering torque input to the steering wheel.

  In other words, according to the above configuration, even in a situation where the first motor and the second motor are driven at the same time, a particularly large power with respect to the steering torque input to the steering wheel must be applied to the steering mechanism. If this is the case, the user's intention can be suitably reflected as power in the steering mechanism. Therefore, as a method of using a plurality of motors that has never been seen before, even if the first motor and the second motor are both driven during emergency steering such as avoiding an obstacle while the vehicle is running, It is possible to propose a usage for favorably giving priority to the user's intention by the configuration of the motor 2.

  Further, the steering control device has an automatic steering mode for controlling the power applying mechanism so as to apply power according to the traveling state of the vehicle independently of steering of the steering wheel. When the first motor is driven using the angle command value, the second motor is driven using the torque command value in a situation where the steering torque is input to the steering wheel. Is desirable.

  According to the above configuration, during an emergency steering operation such as avoiding an obstacle while the vehicle is traveling in the automatic steering mode, the user's intention can be suitably reflected as power on the steering mechanism.

  In the steering control device, the control unit includes a first control unit that controls driving of the first motor and a second control unit that controls driving of the second motor, and the first control unit It is desirable that the same signal be input from the outside to the unit and the second control unit.

  According to the above configuration, the first control unit and the second control unit mutually determine whether or not there is an abnormality by exchanging the results of calculations based on signals input from the outside. Monitoring can be realized. Therefore, the functional safety of the control unit can be improved.

  For example, the first control unit is configured to calculate a torque command value for controlling the driving of the second motor based on a signal input from the outside and transmit the torque command value to the second control unit. The second control unit is configured to receive a torque command value for controlling the driving of the second motor from the first control unit and to be able to perform calculations based on a signal input from the outside. The torque command value received from the first control unit may be configured to determine whether or not it matches the torque command value calculated by itself.

  According to the above configuration, even if the torque command value is not transmitted from the first control unit when the first control unit is abnormal, the second control unit uses the torque command value calculated by itself. It becomes possible to control the driving of the second motor. In addition, since the same signal as the first control unit is input to the second control unit, the driving of the first motor may be controlled based on the angle command value instead of the first control unit. become able to. This is the same even when the second control unit is abnormal. In this case, the first control unit can control the driving of the second motor instead of the second control unit. Therefore, the functional safety of the control unit can be improved more suitably.

  Further, for example, the second control unit receives the torque command value received from the first control unit from the first control unit when determining whether or not it matches the torque command value calculated by itself. When it is determined that the torque command value does not match the torque command value calculated by itself, the first control unit is determined to be abnormal as the torque command value calculated by itself is normal. May be.

  According to the said structure, the priority order that the torque command value calculated by itself is always normal is set about the 2nd control part. Therefore, especially when the first control unit is abnormal, the determination of the abnormality can be quickly derived. Therefore, the functional safety of the control unit can be improved more suitably.

  According to the present invention, it is possible to propose a new way of using a plurality of motors that has never existed before.

The figure which shows the outline about an automatic steering device. The block diagram which shows the electric constitution about an automatic steering device. The block diagram which shows the function which each ECU performs about an automatic steering apparatus. The graph which shows two types of relative rotation angles which the some relative angle sensor provided in the automatic steering apparatus detected, and the angle difference of these relative rotation angles. The graph which illustrates the provision torque characteristic of each control motor. (A)-(c) is a figure which shows the function of 1st steering ECU and 2nd steering ECU for every situation.

Hereinafter, an embodiment of the steering control device will be described.
As shown in FIG. 1, the vehicle is equipped with an automatic steering device 1 that applies power to a steering mechanism 10 to be described later without depending on the steering operation of the driver. The automatic steering device 1 includes a hydraulic power steering device (hereinafter referred to as “HPS”) 2 for applying power and an electric power steering device (hereinafter referred to as “EPS”) 3. The HPS 2 and EPS 3 assist the driver's steering operation by applying a steering force and a steering force as power in accordance with the driver's steering operation. The EPS 3, that is, the automatic steering device 1 is an example of a steering control device.

  The steering mechanism 10 includes a steering wheel 11 operated by a driver and a steering shaft 12 fixed to the steering wheel 11. A pinion shaft 13 is provided at the end of the steering shaft 12 opposite to the steering wheel 11. A pinion gear 13a provided on the pinion shaft 13 is meshed with a rack gear 14a provided on a rack shaft 14 accommodated in a hydraulic cylinder 20 described later. The rotational motion of the pinion shaft 13 is converted into a reciprocating linear motion in the axial direction of the rack shaft 14 via the pinion gear 13a and the rack gear 14a. The reciprocating linear motion is transmitted to the left and right steered wheels 16 and 16 via tie rods 15 and 15 respectively connected to both ends of the rack shaft 14, whereby the steered angles of the steered wheels 16 and 16 are changed. The

  An HPS 2 is provided around the rack shaft 14. The HPS 2 is a hydraulic cylinder 20 that is a generation source of a turning force applied to the rack shaft 14 (steering mechanism 10), a pump 21 that supplies hydraulic oil to the hydraulic cylinder 20, and supply and discharge of hydraulic oil to and from the hydraulic cylinder 20. A valve device 22 to be controlled and a reservoir tank 23 that reserves (stores) hydraulic fluid supplied to and discharged from the hydraulic cylinder 20 by the pump 21 are provided. The pump 21 is mechanically driven and obtains driving force from an engine (internal combustion engine) 4 mounted on the vehicle.

  The cylindrical hydraulic cylinder 20 includes a piston 24 that divides the interior thereof into two hydraulic chambers 20a. The piston 24 is integrally fixed to the rack shaft 14 so as to be movable in the axial direction of the rack shaft 14.

  The valve device 22 is provided with a port 25 for supplying or discharging hydraulic oil. The port 25 is connected to the discharge port of the pump 21, the reservoir tank 23, and each hydraulic chamber 20 a through an oil passage 26. The suction port of the pump 21 is connected to the reservoir tank 23 via a connection pipe 27.

  In the HPS 2, the hydraulic oil sucked up from the reservoir tank 23 by the pump 21 is supplied to the valve device 22 through the oil passage 26 and the connection pipe 27. The hydraulic oil supplied to the valve device 22 is supplied to the hydraulic chamber 20a via the oil passage 26 or discharged from the hydraulic chamber 20a according to the steering operation of the driver. Accordingly, the hydraulic oil is filled in one hydraulic chamber 20a and pressurized, and the hydraulic oil is discharged from the other hydraulic chamber 20a and depressurized. Note that the hydraulic oil discharged from the hydraulic chamber 20a is returned to the reservoir tank 23. As a result, a hydraulic pressure difference is generated between the hydraulic chambers 20a, and the rack shaft 14 moves in the axial direction together with the piston 24 based on the hydraulic pressure difference, thereby assisting the driver's steering operation.

  An EPS 3 is provided in the middle of the steering shaft 12 to which the steering wheel 11 is fixed. The EPS 3 includes a power applying mechanism 30 that is a generation source of a steering force applied to the steering shaft 12 (steering mechanism 10), a control unit 31 that controls the operation of the power applying mechanism 30, and a torque sensor 32.

  The power application mechanism 30 includes an angle control motor 33 and a torque control motor 34 that apply a steering force to the steering shaft 12. A controller 31 is connected to the angle control motor 33 and the torque control motor 34. The angle control motor 33 is connected to the steering shaft 12 via the first speed reducer 33a. The torque control motor 34 is connected to the steering shaft 12 via a second reduction gear 34a having a larger reduction ratio than that of the first reduction gear 33a. The angle control motor 33 is an example of a first motor. The torque control motor 34 is an example of a second motor.

  Specifically, the first pulley 35 is fixed to the rotation shaft of the angle control motor 33. Teeth are provided at equal intervals on the outer periphery of the first pulley 35. The number of teeth of the first pulley 35 is 45, for example. A second pulley 36 is fixed to the rotating shaft of the torque control motor 34. Teeth are provided at equal intervals on the outer periphery of the second pulley 36. The number of teeth of the second pulley 36 is set to be smaller than the number of teeth of the first pulley 35. The number of teeth of the second pulley 36 is 43, for example. A third pulley 37 is fixed to an intermediate portion of the steering shaft 12. Teeth are provided at equal intervals on the outer periphery of the third pulley 37. The number of teeth of the third pulley 37 is 133, for example.

  A first belt 38 is wound between the first pulley 35 and the third pulley 37. The first pulley 35, the third pulley 37, and the first belt 38 function as the first reduction gear 33a. The driving force of the angle control motor 33 is applied to the steering shaft 12 via the first speed reducer 33a.

  A second belt 39 is wound between the second pulley 36 and the third pulley 37. The second pulley 36, the third pulley 37, and the second belt 39 function as the second speed reducer 34a. The driving force of the torque control motor 34 is applied to the steering shaft 12 via the second speed reducer 34a.

  The angle control motor 33 is provided with a first relative angle sensor 33 b that detects a first relative rotation angle θ <b> 1 that is the rotation angle of the rotation shaft of the angle control motor 33. In addition, the torque control motor 34 is provided with a second relative angle sensor 34 b that detects a second relative rotation angle θ <b> 2 that is the rotation angle of the rotation shaft of the torque control motor 34. The first relative angle sensor 33 b and the second relative angle sensor 34 b are connected to the control unit 31. MR sensors are employed as the first relative angle sensor 33b and the second relative angle sensor 34b, respectively. The MR sensor generates two analog signals, a sin signal and a cos signal, according to the rotation of the rotating shaft.

  In the steering shaft 12, a torque sensor 32 is provided between the third pulley 37 and the steering wheel 11. The torque sensor 32 detects a steering torque applied to the steering shaft 12. The torque sensor 32 is connected to the control unit 31.

  An automatic steering ECU 40 that is mounted on the vehicle is connected to the control unit 31. The automatic steering ECU 40 applies a steering force to the steering shaft 12 independently of the driver's steering operation, and automatically changes the steering angle, which is the rotation angle of the steering wheel 11, according to the traveling state of the vehicle. Is instructed to the control unit 31.

Next, the electrical configuration of the automatic steering device 1 (EPS3) will be described.
As shown in FIG. 2, the control unit 31 includes two ECUs, a first steering ECU 41 and a second steering ECU 42. The first steering ECU 41 has a memory 41a, and the second steering ECU 42 has a memory 42a. An angle control motor 33 is connected to the first steering ECU 41 as a control target. A torque control motor 34 is connected to the second steering ECU 42 as a control target. Note that, as indicated by a two-dot chain line in FIG. 2, the first steering ECU 41 is also configured to be able to control the torque control motor 34 when there is an abnormality in the second steering ECU 42. . Similarly, as indicated by a two-dot chain line, the second steering ECU 42 is also configured to be able to control the angle control motor 33 when the first steering ECU 41 has an abnormality. The first steering ECU 41 is an example of a first control unit. The second steering ECU 42 is an example of a second control unit.

  Further, an automatic steering ECU 40 is connected to each of the steering ECUs 41 and 42, respectively. Vehicle information θcon indicating the running state of the vehicle is input to the automatic steering ECU 40. The vehicle information θcon is various information indicating the running state of the vehicle including the surrounding environment of the vehicle recognized by GPS such as a car navigation system, a vehicle speed sensor, an in-vehicle sensor (camera, distance sensor, laser, etc.) and inter-road communication. The automatic steering ECU 40 outputs an angle command value θs * used for automatic steering control generated based on the vehicle information θcon to each of the steering ECUs 41 and 42.

  A torque sensor 32 is connected to each of the steering ECUs 41 and 42. The torque sensor 32 outputs a steering torque τ applied to the steering shaft 12 to each of the steering ECUs 41 and 42. Further, a first relative angle sensor 33b is connected to each of the steering ECUs 41 and 42, respectively. The first relative angle sensor 33b outputs the first relative angle to each of the steering ECUs 41 and 42. Here, for convenience of explanation, “θ1” is given to the output of the first relative angle sensor 33b. Further, a second relative angle sensor 34b is connected to each of the steering ECUs 41 and 42, respectively. The second relative angle sensor 34b outputs the second relative angle to each of the steering ECUs 41 and 42. Here, for convenience of explanation, “θ2” is added to the output of the second relative angle sensor 34b.

  Note that a changeover switch (not shown) is connected to each of the steering ECUs 41 and 42. The changeover switch is operated by the driver, and instructs to change whether or not the respective steering ECUs 41 and 42 set the automatic steering mode in which the automatic steering control is executed. In this embodiment, the steering ECUs 41 and 42 execute automatic steering control related to automatic steering while the setting of the automatic steering mode is instructed, and in parallel with the automatic steering control if there is an intervention operation of the steering operation by the driver. Then, the intervention steering control for assisting the steering operation is executed. Each of the steering ECUs 41 and 42 executes EPS control that assists the steering operation without executing automatic steering control while the setting of the automatic steering mode is not instructed (when it is instructed not to set). In this case, the steering ECUs 41 and 42 may invalidate or not input the angle command value θs * output from the automatic steering ECU 40.

Next, functions of the steering ECUs 41 and 42 will be described in detail.
As shown in FIG. 3, first, the automatic steering ECU 40 executes a target steering angle calculation for generating an optimum angle command value θs * based on the vehicle information θcon every predetermined period. Then, the automatic steering ECU 40 outputs the generated angle command value θs * to each of the steering ECUs 41 and 42 at predetermined intervals. Based on the angle command value θs *, the first steering ECU 41 controls the operation of the angle control motor 33 to drive the motor.

  Specifically, each time the angle command value θs * is input from the automatic steering ECU 40, the first steering ECU 41 determines the steering force (automatic steering) indicating the motor torque to be output to the angle control motor 33 based on the angle command value θs *. An automatic steering torque calculation for generating an automatic steering torque command value Tθ * as a target value of (torque) is executed. The automatic steering torque command value Tθ * indicates the current value supplied to the angle control motor 33. In the automatic steering device 1, the maximum value of the current that can be supplied to the angle control motor 33 is determined in advance.

  In the automatic steering torque calculation, the first steering ECU 41 generates the automatic steering torque command value Tθ * so that the actual rotation angle of the steering shaft 12 (hereinafter referred to as “absolute rotation angle”) matches the angle command value θs *. To do.

  The automatic steering torque calculation executed by the first steering ECU 41 is executed similarly in the second steering ECU 42. In the automatic steering torque calculation executed by the second steering ECU 42, the same angle command value θs * and the same absolute rotation angle of the steering shaft 12 as in the case of the first steering ECU 41 are used. If no abnormality has occurred, the same automatic steering torque command value Tθ * as that of the first steering ECU 41 should be generated.

Here, the calculation of the absolute rotation angle of the steering shaft 12 by the steering ECUs 41 and 42 will be described with reference to FIG.
Each of the steering ECUs 41 and 42 calculates the first relative rotation angle θ1 by obtaining an arc tangent from two analog signals acquired from the first relative angle sensor 33b. Each steering ECU 41, 42 calculates the second relative rotation angle θ2 by obtaining the arc tangent from the two analog signals acquired from the second relative angle sensor 34b.

  The vertical axis of the graph shown in FIG. 4 indicates the first relative rotation angle θ1 and the second relative rotation angle θ2, and the horizontal axis indicates the multiple rotation absolute rotation angle of the steering shaft 12. The broken line indicates the transition of the first relative rotation angle θ1, and the solid line indicates the transition of the second relative rotation angle θ2. Note that the output signals of the first relative angle sensor 33b and the second relative angle sensor 34b each have a shaft angle multiplication factor of 1. Then, due to the difference in the reduction ratio between the angle control motor 33 and the torque control motor 34, the phase of the dashed waveform and the phase of the actual waveform shift with rotation. The first relative rotation angle θ1 and the second relative rotation angle θ2 are rotation angles (0 ° to 360 °) in the detection range of the MR sensor, respectively. That is, from each of the first relative rotation angle θ1 and the second relative rotation angle θ2, the absolute rotation angle, which is the multiple rotation angle of the steering shaft 12, cannot be calculated.

  Accordingly, each of the steering ECUs 41 and 42 calculates an angle difference (| θ1−θ2 |) between the first relative rotation angle θ1 and the second relative rotation angle θ2. The thick line in the graph of FIG. 4 indicates the angle difference. As shown in FIG. 4, as the absolute rotation angle increases, the angle difference (| θ1−θ2 |) increases in proportion to the absolute rotation angle. Therefore, each of the steering ECUs 41 and 42 can calculate the absolute rotation angle from the angle difference (| θ1−θ2 |) by previously grasping the absolute rotation angle with respect to the angle difference (| θ1−θ2 |). it can. The absolute rotation angle with respect to the angle difference (| θ1−θ2 |) is stored in advance in the memories 41a and 42a in the steering ECUs 41 and 42, respectively.

  In addition, each steering ECU41,42 will calculate the rotation angle (absolute rotation angle) of the steering wheel 11, if an ignition signal is input. Each steering ECU 41, 42 calculates an absolute rotation angle by using the first relative rotation angle θ1 and the second relative rotation angle θ2 obtained from the first relative angle sensor 33b and the second relative angle sensor 34b.

  The torque sensor 32 outputs the steering torque τ to each of the steering ECUs 41 and 42 at predetermined intervals. Based on the steering torque τ, the second steering ECU 42 controls the operation of the torque control motor 34 to drive the motor. However, in the present embodiment, the torque command value Tτ * used when the second steering ECU 42 controls the operation of the torque control motor 34 is generated by the first steering ECU 41 and output (transmitted) to the second steering ECU 42. It is supposed to be.

  Specifically, the first steering ECU 41 sets the target value of the steering force (assist torque) indicating the motor torque to be output to the torque control motor 34 based on the steering torque τ each time the steering torque τ is input from the torque sensor 32. Assist torque calculation for generating a torque command value Tτ * is executed. The torque command value Tτ * indicates a current value supplied to the torque control motor 34. In the automatic steering device 1, the maximum value of the current that can be supplied to the torque control motor 34 is determined in advance.

  In the present embodiment, the maximum value of the current supplied to the torque control motor 34 is set to be the same as the maximum value of the current supplied to the angle control motor 33. However, the reduction ratio of the torque control motor 34 (second reduction gear 34a) is set to be larger than the reduction ratio of the angle control motor 33 (first reduction gear 33a).

  Therefore, as shown in FIG. 5, even if the maximum values of the respective torque command values Tθ * and Tτ * (current to be supplied) are set to be the same, the torque control motor 34 uses the angle control motor 33 as the steering shaft 12. The steering force can be applied to the steering shaft 12 as much as the reduction ratio is larger than the steering force applied to the steering shaft 12. That is, the torque control motor 34 (applied torque is large) has a larger maximum value of the steering force (hereinafter referred to as “applied torque”) applied to the steering shaft 12 than the angle control motor 33 (applied torque is small). It is configured.

  The vertical axis of the graph shown in FIG. 5 indicates the maximum value (Tθmax) of the applied torque of the angle control motor 33 and the maximum value (Tτmax) of the applied torque of the torque control motor 34, and the horizontal axis indicates the elapsed time. . A portion highlighted by hatching indicates a range of the applied torque (Tθ) of the angle control motor 33. That is, as shown in the figure, the maximum value (Tτmax) of the applied torque of the torque control motor 34 is configured to be always larger than the maximum value (Tθmax) of the applied torque of the angle control motor 33. .

  Further, as shown in the figure, the first steering ECU 41 determines the current supplied to the control motors 33 and 34 in accordance with the vehicle state (state A, state B, state C) based on the storage state of a battery (not shown). The maximum value is changed. Even in this case, the maximum value (Tτmax) of the applied torque of the torque control motor 34 is configured to be always larger than the maximum value (Tθmax) of the applied torque of the angle control motor 33.

  The assist torque calculation executed by the first steering ECU 41 is executed similarly by the second steering ECU 42. In the assist torque calculation executed by the second steering ECU 42, the same steering torque τ as in the case of the first steering ECU 41 is used. Therefore, if no abnormality has occurred in the automatic steering device 1, the case of the first steering ECU 41 is used. The same torque command value Tτ * should be generated.

  Then, the first steering ECU 41 uses the angle command value θs * to drive the angle control motor 33 so that the actual rotation angle (absolute rotation angle) of the steering shaft 12 matches the angle command value θs *. Control. The first steering ECU 41 controls the motor drive of the angle control motor 33 so as to output the motor torque (small applied torque) of the automatic steering torque command value Tθ *. The rotation speed and rotation angle (absolute rotation angle) of the steering shaft 12 are controlled by the rotation control of the angle control motor 33.

  Further, the second steering ECU 42 controls the motor drive of the torque control motor 34 so as to output the motor torque of the torque command value Tτ * (large applied torque) using the torque command value Tτ *. The driver's steering operation is assisted by the rotation control of the torque control motor 34.

  Note that the steering force applied to the rack shaft 14 by the HPS 2 is added to the outputs of the control motors 33 and 34 of the present embodiment. In other words, the outputs of the control motors 33 and 34 are raised (boosted) by the steering force of the HPS 2 to reduce the burden on the control motors 33 and 34 and to reduce the torque command values Tθ * and Tτ *. The followability to is improved.

  The first steering ECU 41 receives the result of automatic steering torque calculation (automatic steering torque command value Tθ *) from the second steering ECU 42 (indicated by a broken line in FIG. 3). Then, the first steering ECU 41 compares the result of its own automatic steering torque calculation with the automatic steering torque command value Tθ * input (received) from the second steering ECU 42. The control of the second steering ECU 42 is executed to determine whether the second steering ECU 42 is normal and to determine that the second steering ECU 42 is abnormal if they do not match. When determining that the second steering ECU 42 is abnormal, the first steering ECU 41 instructs the second steering ECU 42 to stop the operation (control of driving of the torque control motor 34). Note that when the second steering ECU 42 is instructed to stop the operation, the second operation ECU 42 stops the subsequent operation and does not execute any control.

  On the other hand, the second steering ECU 42 compares the result of its own assist torque calculation with the torque command value Tτ * input (received) from the first steering ECU 41, and the first steering ECU 41 is normal if they match. And monitoring control of the first steering ECU 41 is executed to determine that the first steering ECU 41 is abnormal when they do not match. When determining that the first steering ECU 41 is abnormal, the second steering ECU 42 instructs the first steering ECU 41 to stop the operation (control of driving of the angle control motor 33). The first steering ECU 41, when instructed to stop the operation, stops the subsequent operation and does not execute any control.

  As described above, the steering ECUs 41 and 42 are configured to perform the same calculation based on the input angle command value θs *, the steering torque τ, the first relative rotation angle θ1, and the second relative rotation angle θ2. Yes. Each of the steering ECUs 41 and 42 performs calculations related to the control that is mainly executed (automatic steering torque calculation related to the angle control motor 33 if the first steering ECU 41, and torque control motor if the second steering ECU 42). As for the assist torque calculation related to No. 34, the supervisory control is executed in which the priority order that the calculation is always normal is set. Based on the priority order set in this way, mutual monitoring for monitoring each other is realized.

According to the present embodiment described above, the following operations and effects are achieved.
(1) For example, depending on the torque control motor 34 driven using the torque command value Tτ * based on the steering torque input to the steering wheel 11, the user's intention can be reflected in the steering mechanism 10 as the steering force. . During emergency steering such as avoiding obstacles during traveling of the vehicle in the automatic steering mode, a large applied torque is often required with respect to the steering torque input to the steering wheel 11.

  In this respect, in the present embodiment, even when the angle control motor 33 and the torque control motor 34 are driven at the same time, that is, even in the automatic steering mode, the steering torque input to the steering wheel 11 is particularly large. When torque is required, the user's intention can be suitably reflected as a steering force on the steering mechanism 10. Therefore, as an unprecedented usage of a plurality of motors, both the angle control motor 33 and the torque control motor 34 are driven during emergency steering such as obstacle avoidance while the vehicle is running in the automatic steering mode. Even if this is the case, it is possible to propose a usage for favorably giving priority to the user's intention by the configuration of the torque control motor 34.

  (2) An angle command value θs *, a steering torque τ, a first relative rotation angle θ1, and a second relative rotation angle θ2 are input to the steering ECUs 41 and 42, respectively. Whether there is an abnormality between the steering ECUs 41 and 42 by exchanging the result of the automatic steering torque calculation (automatic steering torque command value Tθ *) and the result of the assist torque calculation (torque command value Tτ *). Mutual monitoring to determine whether or not is realized. Therefore, the functional safety of each steering ECU 41, 42 can be improved.

  (3) The first steering ECU 41 calculates a torque command value Tτ * for controlling the driving of the torque control motor 34 based on the steering torque τ input from the torque sensor 32 and transmits it to the second steering ECU 42. It is configured as follows. Then, the second steering ECU 42 receives the torque command value Tτ * for controlling the torque control motor 34 from the first steering ECU 41, and also calculates itself based on the steering torque τ input from the torque sensor 32, Monitoring control of the first steering ECU 41 is executed.

  That is, even if the first steering ECU 41 is abnormal, even if the torque command value Tτ * is not transmitted from the first steering ECU 41, the second steering ECU 42 uses the torque command value Tτ * calculated by itself. Can be controlled. In addition, since the same signal as that of the first steering ECU 41 is input to the second steering ECU 42, the driving of the angle control motor 33 can be controlled instead of the first steering ECU 41 based on the angle command value θs *. . This is the same even when the second steering ECU 42 is abnormal. In this case, the first steering ECU 41 can control the driving of the torque control motor 34 instead of the second steering ECU 42.

Here, with reference to FIGS. 6A to 6C, functions of the respective steering ECUs 41 and 42 for each situation will be described.
As shown in FIG. 6A, the first steering ECU 41 functions to execute automatic steering control and second steering ECU monitoring when the steering ECUs 41 and 42 are both normal and abnormal. Further, the second steering ECU 42 functions to execute EPS control, intervention steering control, and first steering ECU monitoring when the steering ECUs 41 and 42 are both normal and abnormal. The second steering ECU monitoring is monitoring control of the second steering ECU 42 executed by the first steering ECU 41. The first steering ECU monitoring is a monitoring control of the first steering ECU 41 executed by the second steering ECU 42.

  As shown in FIG. 6B, when the first steering ECU 41 has an abnormality (the first steering ECU has failed) and the second steering ECU 42 is normal and has no abnormality, the first steering ECU 41 does not function. In this case, the second steering ECU 42 functions to execute automatic steering control, EPS control, and intervention steering control. Even in this case, since the second steering ECU 42 calculates the automatic steering torque command value Tθ * by the automatic steering torque calculation based on the angle command value θs *, the angle control motor 33 is based on the angle command value θs *. Can be controlled. Further, since the second steering ECU 42 calculates the torque command value Tτ * by the assist torque calculation based on the steering torque τ, the second steering ECU 42 can control the driving of the torque control motor 34 based on the torque command value Tτ *. As a result, the second steering ECU 42 can make the function executed by the first steering ECU 41 redundant.

  On the other hand, as shown in FIG. 6C, when the second steering ECU 42 is abnormal (second steering ECU failure) and the first steering ECU 41 is normal and normal, the second steering ECU 42 does not function. In this case, the first steering ECU 41 functions to execute automatic steering control, EPS control, and intervention steering control. Even in this case, since the first steering ECU 41 calculates the torque command value Tτ * by the assist torque calculation based on the steering torque τ, it is possible to control the driving of the torque control motor 34 based on the steering torque τ. it can. Thereby, the first steering ECU 41 can make the function executed by the second steering ECU 42 redundant.

Therefore, the functional safety of each steering ECU 41, 42 can be improved more suitably.
(4) In the second steering ECU 42, at least the torque control value Tτ * calculated by the second steering ECU 42 is subjected to monitoring control in which a priority order is set so that it is always normal. Note that the first steering ECU 41 is configured to execute monitoring control in which a priority order is set that at least the automatic steering torque command value Tθ * calculated by itself is always normal. Therefore, when each of the steering ECUs 41 and 42 is abnormal, the determination of the abnormality can be quickly derived. Therefore, the functional safety of each steering ECU 41, 42 can be improved more suitably.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
The mutual monitoring is realized in each of the steering ECUs 41 and 42, but it is sufficient that at least the monitoring of the first steering ECU 41 by the second steering ECU 42 is realized. In this case, monitoring of the second steering ECU 42 may be left to self-determination (self-check) of the second steering ECU 42.

  In the monitoring of each of the steering ECUs 41 and 42, the priority order indicating normality may be set to only one of the steering ECUs 41 and 42. Even in this case, the effect according to the above effect (4) can be obtained.

  The second steering ECU 42 may be configured to use the torque command value Tτ * calculated by itself when controlling the driving of the torque control motor 34. The first steering ECU 41 may be configured to use the automatic steering torque command value Tθ * input from the second steering ECU 42 when controlling the driving of the angle control motor 33. Further, each of the steering ECUs 41 and 42 may be configured as one ECU as the control unit 31.

  The steering ECUs 41 and 42 may be configured to receive only signals necessary for control. In this case, for example, a signal that is input only to the first steering ECU 41 can also be implemented for mutual monitoring by being configured to be input to the second steering ECU 42 via the first steering ECU 41. .

  In the above embodiment, when an intervention operation is performed while the setting of the automatic steering mode is instructed, the automatic steering control is interrupted or stopped so that the automatic steering mode setting is not instructed, that is, the EPS control is switched. You may apply to the automatic steering device 1 made into. Thereby, when switching from automatic steering control to EPS control, the torque control motor 34 having a large reduction ratio can be driven to prioritize the intervention operation. Therefore, at the time of switching from automatic steering control to EPS control, even if the switching is not performed normally and the angle control motor 33 is driven, the intention of the user is preferably reflected in the steering mechanism 10 as the steering force. Can do.

  The torque control motor 34 is set so that the maximum value of the current that can be supplied compared to the angle control motor 33 is increased, or the number of windings is increased compared to the angle control motor 33, The output of the motor itself may be larger than that of the angle control motor 33. In this case, even if the speed reduction ratio of the second speed reducer 34a is the same as the speed reduction ratio of the first speed reducer 33a, the torque control motor 34 is compared with the angle control motor 33 (in this case, the maximum value of applied torque). The maximum output of the motor itself). In this modification, if the reduction ratio of the second reduction gear 34a and the reduction ratio of the first reduction gear 33a are made the same, the steering angle at which the steering shaft 12 can detect the absolute rotation angle of the steering shaft 12 is detected. A sensor may be provided separately.

-Although the MR sensor was used as the 1st relative angle sensor 33b and the 2nd relative angle sensor 34b, a Hall sensor may be used and a resolver may be used.
The angle control motor 33 and the torque control motor 34 may be connected to the steering shaft 12 via gears instead of the belt.

The number of teeth of the first pulley 35, the number of teeth of the second pulley 36, and the number of teeth of the third pulley 37 can be arbitrarily set as long as the reduction ratio is maintained.
The power applying mechanism 30 only needs to have at least one angle control motor 33 and one torque control motor 34. Two or more angle control motors 33 or two torque control motors 34 may be provided. You may make it provide above. In this case, the absolute rotation angle may be calculated from the rotation angle difference between at least two of the angle control motor 33 and the torque control motor 34.

-You may make it calculate the rotation angle of the pinion shaft 13 by changing the position in which each control motor 33 and 34 is provided.
In the above embodiment, the specifications of the HPS 2 may be changed, for example, a ball screw type hydraulic power steering device. In addition, the generation source of the turning force applied to the rack shaft 14 (steering mechanism 10) may be an electric power steering device (EPS). For such an electric power steering apparatus, a rack type electric power steering apparatus that applies a steering force to the rack shaft 14 may be adopted.

  -The above-mentioned embodiment is applicable also to a steering device which does not have automatic steering mode. In this case, the angle control motor 33 is used, for example, to apply power to the steering shaft 12 by a skid prevention device (vehicle stability control).

  -The above-mentioned embodiment is applicable also to a steer-by-wire type steering device, for example. In this case, the HPS 2 may be provided with a valve device 22 that has been changed to an electrically controlled specification. The valve device 22 may be controlled by the first steering ECU 41 using the angle command value θs *. In the first steering ECU 41, the position (or the amount of movement) of the steered shaft (equivalent to the rack shaft 14 in the above embodiment) for turning the left and right steered wheels 16 and 16 by the reciprocating linear motion in the axial direction is an angle command value. What is necessary is just to control the valve apparatus 22 (hydraulic pressure difference of each hydraulic chamber 20a) so that it may correspond with the position (or movement amount) of the turning axis calculated based on (theta) s *. In this case, the angle control motor 33 (power applying mechanism 30) provides power (steering) to the steering shaft 12 (steering mechanism 10) so that the steering wheel 11 rotates according to the turning of the steered wheels 16 and 16 during automatic steering. To function). In addition, the torque control motor 34 (power supply mechanism 30) provides power to the steering shaft 12 (steering mechanism 10) so that a load is generated on the steering wheel 11 in accordance with the steering torque applied to the steering shaft 12 during automatic steering. It functions to give reaction force. In addition, the generation source of the turning force applied to the rack shaft 14 (steering mechanism 10) may be an electric power steering device (EPS) as in the above-described embodiment or the above-described modification. As such an electric power steering device, an electric power steering device of a type that imparts a turning force to the turning shaft may be adopted. In addition, you may apply this modification in combination with the other modification mentioned above.

  DESCRIPTION OF SYMBOLS 1 ... Automatic steering device, 3 ... Electric power steering device, 10 ... Steering mechanism, 11 ... Steering wheel, 12 ... Steering shaft, 16 ... Steering wheel, 30 ... Power application mechanism, 31 ... Control part, 32 ... Torque sensor, 33 ... angle control motor, 34 ... torque control motor, 40 ... automatic steering ECU, 41 ... first steering ECU, 42 ... second steering ECU, θs * ... angle command value, Tτ * ... torque command value, Tθmax, Tτmax ... Maximum torque value.

Claims (5)

In a steering control device including a power applying mechanism configured to include a first motor and a second motor that apply power to a steering mechanism configured to include a steering wheel that enables steering wheels to be steered. ,
The driving of the first motor is controlled using an angle command value based on the rotation angle of the steering wheel, and the second motor is driven using a torque command value based on a steering torque input to the steering wheel. A control unit for controlling
In a situation where the first motor and the second motor are driven simultaneously, the maximum value of the power that the second motor driven using the torque command value applies to the steering mechanism is A steering control device, wherein the first motor driven using the angle command value is configured to be larger than a maximum value of power applied to the steering mechanism. An automatic steering mode for controlling the power application mechanism so as to apply the power according to a running state of a vehicle independently of steering of the steering wheel;
The controller uses the torque command value when the steering torque is input to the steering wheel when the first motor is driven using the angle command value during the automatic steering mode. The steering control device according to claim 1, wherein the steering control device is configured to drive the second motor. The control unit includes a first control unit that controls driving of the first motor, and a second control unit that controls driving of the second motor,
The steering control device according to claim 1 or 2, wherein the first control unit and the second control unit are configured such that the same signal is input from outside. The first control unit is configured to calculate the torque command value for controlling the driving of the second motor based on a signal input from the outside, and to transmit the torque command value to the second control unit. Has been
The second control unit is configured to receive the torque command value for controlling the driving of the second motor from the first control unit, and to be able to calculate based on a signal input from the outside. The steering control device according to claim 3, wherein the steering control device is configured to determine whether or not the torque command value received from the first control unit matches the torque command value calculated by itself. .   The second control unit receives from the first control unit when determining whether the torque command value received from the first control unit matches the torque command value calculated by itself. When it is determined that the torque command value calculated by itself does not match the torque command value calculated by itself, the torque control value calculated by itself is normal and the first control unit is abnormal. The steering control device according to claim 4, wherein the steering control device is configured to make a determination.

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