JP2022053436A - Steering control device - Google Patents

Abstract

To provide a steering control device that can simply set steering reaction force.SOLUTION: A steering control device includes a steering side control unit that controls operation of a steering side motor. The steering side control unit includes a target reaction torque calculation unit that calculates target reaction torque as a target value of motor torque as steering reaction force. The target reaction torque calculation unit includes a deviation axial force calculation unit 73 that calculates deviation axial force Fx reflected into the target reaction torque for restricting steering that allows turning wheels to turn in a predetermined direction. The deviation axial force calculation unit 73 calculates the deviation axial force Fv based on a deviation between a steering angle θs and a steering conversion angle θp_s obtained by converting a pinion angle to the steering angle in accordance with a steering angle ratio.SELECTED DRAWING: Figure 3

Description

The present invention relates to a steering control device.

Conventionally, as a kind of steering device, a steer-by-wire type steering device in which a power transmission path is separated between a steering section steered by the driver and a steering section that steers the steering wheel according to the steering of the driver. There is. In the same type of steering device, road surface information such as the road surface reaction force received by the steering wheel is not mechanically transmitted to the steering wheel. Therefore, in the steering control device that controls the steering device of the same type, the steering side actuator provided in the steering unit is controlled so as to exert a steering reaction force in consideration of the road surface information on the steering wheel. There is something that controls the road surface information to be transmitted to the driver.

For example, in the steering control device of Patent Document 1, when determining the steering reaction force, the axial force acting on the steering shaft provided in the steering portion is taken into consideration, and the steering wheel is used as one of the considering axial forces. When the rudder hits an obstacle such as a rim stone, the axial force of the obstacle pad that informs the driver of the situation is used. In this case, when the steering wheel hits an obstacle, the steering control device is further steered by the driver in one direction on the obstacle side by increasing the axial force of the obstacle contact. I try to limit it.

Japanese Unexamined Patent Publication No. 2019-127217

In the steering control device, various types of axial forces other than the above-mentioned obstacle contact axial force may be considered as the axial force to be considered for determining the steering reaction force. In this respect, the axial force for notifying the driver of the situation where the steering wheel hits the obstacle is set by paying attention to the situation where the steering wheel hits the obstacle. On the other hand, other types of axial forces must be set by focusing on the situation of the steering wheel, which is different from the situation where the steering wheel hits an obstacle. For this reason, when determining the steering reaction force in consideration of various types of axial force, the axial force must be set individually for each situation to be focused on, so that the steering reaction force must be determined. There was a risk that the setting of the axial force to be considered would be complicated.

An object of the present invention is to provide a steering control device capable of suppressing complicated setting of an axial force to be considered for determining a steering reaction force.

The steering control device that solves the above problems is between a steering unit connected to the steering wheel and a steering unit that steers the steering wheel by operating the steering shaft according to the steering input to the steering unit. A steering control device for controlling a steering device having a structure in which the power transmission paths of the above are separated, wherein the steering device has a steering angle ratio which is a ratio of the rotation amount of the steering wheel to the rotation amount of the steering wheel. A control unit that has a function of changing and at least controls the operation of the steering side motor provided in the steering unit so as to generate a steering reaction force that is a force that opposes the steering input to the steering unit. The control unit has a target reaction force torque calculation unit that calculates a target reaction force torque that is a target value of the motor torque of the steering side motor that is the steering reaction force, and the target reaction force torque calculation unit is provided. The deviation axial force calculation unit includes a deviation axial force calculation unit for calculating a deviation axial force for regulating steering for steering the steering wheel in a predetermined direction, which is reflected in the target reaction force torque. The steering angle and the steering angle are defined by using one of the steering angle set as a value indicating the rotation amount of the steering wheel and the steering angle set as a value indicating the rotation amount of the steering wheel as a reference angle. The deviation axial force is calculated based on the deviation between the reference angle and the conversion angle, with the conversion angle of either one of the steering angles as the conversion angle. There is.

In the above configuration, the deviation axial force is calculated based on the deviation between the reference angle and the conversion angle. In this case, in consideration of the change in the steering angle ratio, when calculating the deviation between the reference angle and the conversion angle, one of the steering angle and the steering angle is converted according to the steering angle ratio. Is adopted. As a result, the deviation between the reference angle and the converted angle can be calculated as a deviation in consideration of the steering angle ratio at that time when the relationship between the steering angle and the steering angle is deviated. Then, if the deviation axial force based on the deviation between the reference angle and the conversion angle is set, it is possible to consider multiple types of axial force collectively. Therefore, the axial force is individually set for each situation in which the axial force should be generated. No need to set. Therefore, it is possible to prevent the setting of the axial force to be considered for determining the steering reaction force from becoming complicated.

In the steering control device, the deviation axial force calculation unit adjusts the deviation axial force component calculation unit for calculating the deviation axial force component based on the deviation between the reference angle and the conversion angle, and the change of the deviation axial force. Therefore, the deviation axial force includes the axial force viscous component calculation unit for calculating the axial force viscous component based on the angular velocity which is the change amount of the reference angle or the conversion angle, and the deviation axial force is relative to the deviation axial force component. , It is preferable that the structure is such that it can be obtained by reflecting the axial force viscous component.

According to the above configuration, for example, when the axial force viscosity component is calculated so that the change amount of the deviation axial force component becomes smaller as the angular velocity is larger, it is possible to suppress the sudden change in the deviation axial force. .. In this case, the elastic feeling of the steering wheel when the steering wheel hits an obstacle, the viscous feeling when the steering wheel is steered, and the rigidity of the mechanical configuration from the steering wheel to the steering wheel are reproduced. By transmitting the steering reaction force to the driver, it is possible to more accurately convey the situation actually occurring on the steering wheel.

In the steering control device, a turning state amount set as information indicating a difference in the actual turning behavior of the vehicle with respect to the ideal turning behavior of the vehicle is input to the control unit, and the deviation axial force calculation unit is used. Is preferably configured to calculate the deviation using the steering angle compensated based on the turning state quantity.

According to the above configuration, there may be a situation in which the actual turning behavior of the vehicle deviates from the ideal turning behavior of the vehicle in the running state during turning. You will be able to tell or adjust.

In the steering control device, the deviation axial force calculation unit is obtained based on the deviation so that the first deviation axial force component obtained based on the deviation and the first deviation axial force component have different characteristics. The deviation axial force component calculation unit includes a deviation axial force component calculation unit that calculates a plurality of deviation axial force components including the two deviation axial force components, and the deviation axial force component calculation unit operates the steering side motor provided in the steering unit. Any deviation axial force component of the first deviation axial force component and the second deviation axial force component is added to the deviation axial force depending on whether the situation is not limited or the operation is restricted. It is preferable that it is configured as follows.

According to the above configuration, the deviation between the reference angle and the conversion angle is caused by the change in the followability of the steering angle depending on whether or not the operation of the steering side motor is restricted. It is conceivable that the appearance of the size of the rudder will change. In this case, which of the first deviation axial force component and the second deviation axial force component is added to the deviation axial force is switched depending on whether or not the situation is restricted. As a result, an appropriate deviation axial force can be calculated depending on whether or not the operation of the steering side motor is restricted.

In the steering control device, the deviation axial force component calculation unit switches between a situation in which the operation of the steering side motor is not restricted and a situation in which the operation is restricted, and thus the first deviation axis. When switching between the force component and the second deviation axial force component to be added to the deviation axial force, the difference between the first deviation axial force component and the second deviation axial force component before and after the switching is gradually increased. It is preferable that it is configured to have a function of reducing the size.

According to the above configuration, which of the first deviation axial force component and the second deviation axial force component is added to the deviation axial force due to the switching of whether or not the operation of the steering side motor is restricted. Even if there is a difference between the first deviation axial force component and the second deviation axial force component before and after the switching, the difference can be gradually reduced. As a result, sudden changes in the deviation axial force can be suppressed depending on whether or not the operation of the steering side motor is not restricted.

In the steering control device, the deviation axial force calculation unit is obtained based on the deviation so that the first deviation axial force component obtained based on the deviation and the first deviation axial force component have different characteristics. A deviation axial force component calculation unit that sums up a plurality of deviation axial force components including a deviation axial force component at a predetermined distribution ratio is included, and the deviation axial force component calculation unit is a steering side provided in the steering unit. The distribution ratio is changed according to whether the operation of the motor is not restricted or the operation is restricted, and the deviation axial force component added up by the distribution ratio is added to the deviation axial force. It is preferable that it is configured in.

According to the above configuration, the deviation between the reference angle and the conversion angle is caused by the change in the followability of the steering angle depending on whether or not the operation of the steering side motor is restricted. Since it is possible that the appearance of the above-mentioned size will change, the distribution ratio between the first deviation axial force component and the second deviation axial force component is changed depending on whether or not the situation is restricted. .. As a result, an appropriate deviation axial force can be calculated depending on whether or not the operation of the steering side motor is restricted.

In the steering control device, the deviation axial force component calculation unit changes the distribution ratio due to switching between a situation in which the operation of the steering side motor is not restricted and a situation in which the operation is restricted. When doing so, it is preferable that the distribution ratio is configured to have a function of gradually changing.

According to the above configuration, when the distribution ratio is changed due to the switching of whether or not the operation of the steering side motor is restricted, the change can be gradually reflected. As a result, sudden changes in the deviation axial force can be suppressed depending on whether or not the operation of the steering side motor is not restricted.

In the steering control device, when the absolute value of the deviation is equal to or greater than the deviation threshold value, the deviation axial force component calculation unit determines the deviation with respect to the deviation as compared with the case where the absolute value of the deviation is less than the deviation threshold value. The deviation axial force component calculation unit is configured to set a large gradient of the axial force component, and in a situation where the operation of the steering side motor is restricted, the operation of the steering side motor is not restricted. In comparison, it is preferable that the absolute value of the deviation threshold is set to be smaller.

According to the above configuration, in a situation where the operation of the steering side motor is restricted, it is conceivable that the deviation between the reference angle and the conversion angle becomes large due to the decrease in the followability of the steering angle. However, it is possible to prevent the deviation from becoming large.

Here, considering the situation where the steering of the steering wheel is regulated by the steering limit of the steering wheel, that is, the steering limit of the steering wheel, the steering wheel is actually on the steering limit side in the situation where the steering wheel cannot be steered by the deviation axial force. If there is no deviation between the reference angle and the conversion angle beyond the above, the steering of the steering wheel cannot be regulated.

Therefore, in the steering control device, the target reaction force torque calculation unit includes an end axial force calculation unit that calculates an end axial force for restricting steering in a direction exceeding the steering angle limit, and includes the target reaction force calculation unit. It is preferable that the force torque calculation unit is configured to have a function of individually calculating the deviation axial force and the end axial force.

According to the above configuration, when the steering angle exceeds the steering angle limit, the end axial force is set separately from the deviation axial force to steer the steering wheel in the direction exceeding the steering angle limit. Will be able to regulate. Thereby, for example, when the steering wheel has reached the steering angle limit, the steering of the steering wheel can be regulated even in a situation where there is no deviation between the reference angle and the converted angle.

In the steering control device, the target reaction force torque calculation unit has an axial force selection unit that selects the axial force having the largest absolute value among a plurality of axial forces including the deviation axial force and the end axial force. However, it is preferable that the target reaction force torque calculation unit is configured to obtain the target reaction force torque by reflecting the axial force selected by the axial force selection unit.

According to the above configuration, there is a situation where a plurality of axial forces including the deviation axial force and the end axial force are calculated as values that should generate the steering reaction force at the same time, but even in such a situation, the target reaction force is actually calculated. It is the only axial force that has the largest absolute value as the axial force reflected in torque. Therefore, even in a situation where a plurality of axial forces including the deviation axial force and the end axial force are calculated as values that should generate the steering reaction force at the same time, it is possible to suppress the steering reaction force from becoming excessively large. can.

In the steering control device, the control unit includes a steering side control unit that executes reaction force control for generating the steering reaction force through drive control of the steering side motor, and a steering side motor provided in the steering unit. The steering side control unit is provided with a steering side control unit that executes steering control for steering the steering wheel through the drive control of the vehicle, and the steering side control unit is based on a vehicle speed value set as information indicating the traveling speed of the vehicle. , A steering angle ratio variable control unit that controls to change the steering angle ratio, and a steering angle conversion unit that calculates a steering conversion angle obtained by converting the steering angle into the steering angle according to the steering angle ratio. The reference angle is preferably the steering angle, and the conversion angle is preferably the steering conversion angle.

According to the above configuration, the steering side control unit provided with the steering angle ratio variable control unit has a steering angle conversion unit. In this case, the function of converting using the steering angle ratio can be integrated in the steering side control unit, and a configuration that is easy to design when designing the control unit can be realized.

According to the steering control device of the present invention, the setting of the steering reaction force can be simplified.

The figure which shows the schematic structure of the steering device of the steer-by-wire type in 1st Embodiment. The block diagram which shows the function of the steering control device in 1st Embodiment. The block diagram which shows the function of the axial force calculation part in 1st Embodiment. The block diagram which shows the function of the distribution axial force calculation part in 1st Embodiment. The block diagram which shows the function of the deviation axial force calculation part in 1st Embodiment. In the second embodiment, the block diagram which shows the function of the deviation axial force calculation part.

<First Embodiment>
The first embodiment of the steering control device will be described with reference to the drawings.
As shown in FIG. 1, the steering device 2 of the vehicle to be controlled by the steering control device 1 is configured as a steer-by-wire type steering device. The steering device 2 includes a steering unit 4 that is steered by the driver via the steering wheel 3, and a steering unit 6 that steers the steering wheel 5 according to the steering input to the steering unit 4 by the driver. ing.

The steering unit 4 includes a steering shaft 11 to which the steering wheel 3 is fixed, and a steering actuator 12 that applies a steering reaction force, which is a force that opposes the steering of the driver, to the steering wheel 3 via the steering shaft 11. There is. The steering actuator 12 has a steering side motor 13 as a drive source, and a steering side deceleration mechanism 14 that decelerates the rotation of the steering side motor 13 and transmits the rotation to the steering shaft 11. For the steering side motor 13 of the present embodiment, for example, a three-phase brushless motor is adopted.

The steering unit 6 includes a first pinion shaft 21 and a rack shaft 22 as a steering shaft connected to the first pinion shaft 21. The first pinion shaft 21 and the rack shaft 22 are arranged at a predetermined crossing angle. The first rack and pinion mechanism 23 is configured by engaging the pinion teeth 21a formed on the first pinion shaft 21 and the first rack teeth 22a formed on the rack shaft 22. Tie rods 24 are connected to both ends of the rack shaft 22. The tip of the tie rod 24 is connected to a knuckle (not shown) to which the left and right steering wheels 5 are assembled.

The steering unit 6 includes a steering actuator 31 that applies a steering force for steering the steering wheel 5 to the rack shaft 22. The steering actuator 31 applies a steering force to the rack shaft 22 via the second pinion shaft 32. The steering actuator 31 includes a steering side motor 33 as a drive source, and a steering side deceleration mechanism 34 that decelerates the rotation of the steering side motor 33 and transmits the rotation to the second pinion shaft 32. The second pinion shaft 32 and the rack shaft 22 are arranged at a predetermined crossing angle. The second rack and pinion mechanism 35 is configured by engaging the second pinion teeth 32a formed on the second pinion shaft 32 and the second rack teeth 22b formed on the rack shaft 22.

In the steering device 2 configured in this way, the second pinion shaft 32 is rotationally driven by the steering actuator 31 in response to the steering operation by the driver, and this rotation is driven by the second rack and pinion mechanism 35 to rotate the shaft of the rack shaft 22. By converting to directional movement, the steering angle of the steering wheel 5 is changed. At this time, from the steering actuator 12, a force acting in the direction opposite to the steering direction by the driver is applied to the steering wheel 3 as a steering reaction force against the steering of the driver.

Incidentally, the reason why the first pinion shaft 21 is provided is to support the rack shaft 22 together with the first pinion shaft 21 inside a housing (not shown). That is, the rack shaft 22 is movably supported along the axial direction thereof by a support mechanism (not shown) provided in the steering device 2, and is pressed toward the first pinion shaft 21 and the second pinion shaft 32. .. As a result, the rack shaft 22 is supported inside the housing. However, another support mechanism for supporting the rack shaft 22 on the housing may be provided without using the first pinion shaft 21.

The electrical configuration of the steering device 2 will be described.
The steering control device 1 is connected to the steering side motor 13 and the steering side motor 33. The steering control device 1 controls the operation of the steering side motor 13 and the steering side motor 33. The steering control device 1 includes a central processing unit and a memory (not shown). The steering control device 1 executes various controls by the CPU executing a program stored in the memory at predetermined calculation cycles.

A torque sensor 41 that detects the steering torque Th applied to the steering shaft 11 is connected to the steering control device 1. The torque sensor 41 is provided on the steering wheel 3 side of the steering shaft 11 connected to the steering side deceleration mechanism 14. The torque sensor 41 detects the steering torque Th based on the twist of the torsion bar provided in the middle of the steering shaft 11. A steering side rotation angle sensor 42 and a steering side rotation angle sensor 43 are connected to the steering control device 1.

The steering-side rotation angle sensor 42 detects the steering-side rotation angle θa of the steering-side motor 13 at a relative angle within a range of 360 degrees. The steering angle θa is used to calculate the steering angle θs. The steering side motor 13 and the steering shaft 11 are interlocked with each other via the steering side deceleration mechanism 14. Therefore, there is a correlation between the steering side rotation angle θa of the steering side motor 13 and the rotation angle of the steering shaft 11, and thus the rotation angle of the steering wheel 3, that is, the steering angle θs set as information indicating the rotation amount. be. Therefore, the steering angle θs can be calculated based on the steering angle θa of the steering side motor 13.

The steering-side rotation angle sensor 43 detects the steering-side rotation angle θb of the steering-side motor 33 as a relative angle. The steering-side rotation angle θb is used in the calculation of the pinion angle θp. The steering side motor 33 and the second pinion shaft 32 are interlocked with each other via the steering side deceleration mechanism 34. Therefore, there is a correlation between the steering-side rotation angle θb of the steering-side motor 33 and the pinion angle θp, which is the actual rotation angle of the second pinion shaft 32. Therefore, the pinion angle θp can be calculated based on the steering side rotation angle θb of the steering side motor 33. Further, the second pinion shaft 32 is meshed with the rack shaft 22. Therefore, there is also a correlation between the pinion angle θp and the amount of movement of the rack shaft 22. That is, the pinion angle θp is a value that reflects the steering angle of the steering wheel 5. The steering torque Th, the steering side rotation angle θa, and the steering side rotation angle θb are positive values when steering to the right and negative values when steering to the left.

A vehicle speed sensor 44 is connected to the steering control device 1. The vehicle speed sensor 44 detects a vehicle speed value V set as information indicating the traveling speed of the vehicle.
An upper control device 45 is connected to the steering control device 1. The upper control device 45 is mounted on a vehicle on which the steering device 2 is mounted as a control device separate from the steering control device 1. The host control device 45 seeks an optimum control method based on the state of the vehicle at that time, and commands various in-vehicle control devices to perform individual control according to the required control method. The upper control device 45 of the present embodiment is a drift state defined by an angle as a turning state amount set as information indicating a difference in the actual turning behavior of the vehicle with respect to the ideal turning behavior of the vehicle in the running state during turning. Generate the quantity θx. For example, a yaw rate sensor is connected to the upper control device 45, and an estimation calculation is performed based on the actual yaw rate detected through the yaw rate sensor and the running state such as the vehicle speed value V during turning. Based on the deviation from the estimated yaw rate, the drift state quantity θx is calculated as a value having an angle dimension. The drift state quantity θx thus obtained is output to the steering control device 1.

The steering control device 1 executes reaction force control that generates a steering reaction force according to the steering torque Th through the drive control of the steering side motor 13. Further, the steering control device 1 executes steering control for steering the steering wheel 5 according to the steering state through the drive control of the steering side motor 33.

The function of the steering control device 1 will be described.
The steering control device 1 includes a central processing unit (CPU) and a memory (not shown), and the CPU executes a program stored in the memory at predetermined calculation cycles. As a result, various processes are executed.

FIG. 2 shows a part of the processing executed by the steering control device 1. The process shown in FIG. 2 describes a part of the process realized by the CPU executing the program stored in the memory for each type of the realized process.

As shown in FIG. 2, the steering control device 1 includes a steering side control unit 50 that executes reaction force control and a steering side control unit 60 that executes steering control.
The steering side control unit 50 has a steering side current sensor 54. The steering-side current sensor 54 is provided on a connecting line between the steering-side control unit 50 and the motor coils of each phase of the steering-side motor 13. The steering-side current sensor 54 detects the steering-side actual current value Ia obtained from the current values of each phase of the steering-side motor 13 flowing through the connection line. The steering-side current sensor 54 acquires the voltage drop of the shunt resistor connected to each source side of the switching element as a current in an inverter (not shown) provided corresponding to the steering-side motor 13. In addition, in FIG. 2, for convenience of explanation, the connection line of each phase and the current sensor of each phase are shown together as one.

The steering side control unit 60 has a steering side current sensor 67. The steering-side current sensor 67 is provided on a connecting line between the steering-side control unit 60 and the motor coils of each phase of the steering-side motor 33. The steering-side current sensor 67 detects the steering-side actual current value Ib obtained from the current values of each phase of the steering-side motor 33 flowing through the connection line. The steering side current sensor 67 acquires the voltage drop of the shunt resistor connected to each source side of the switching element as a current in an inverter (not shown) provided corresponding to the steering side motor 33. In addition, in FIG. 2, for convenience of explanation, the connection line of each phase and the current sensor of each phase are shown together as one.

The function of the steering side control unit 50 will be described.
The steering side control unit 50 has a steering torque Th, a vehicle speed value V, a steering side rotation angle θa, a steering side actual current value Ib, a target pinion angle θp * described later, a steering conversion angle θp_s described later, and a code described later. The signal Sm is input. The steering side control unit 50 supplies power to the steering side motor 13 based on the steering torque Th, the vehicle speed value V, the steering side rotation angle θa, the steering side actual current value Ib, the steering conversion angle θp_s, and the code signal Sm. Control. The steering conversion angle θp_s is calculated based on the steering side rotation angle θb.

The steering side control unit 50 includes a steering angle calculation unit 51, a target reaction force torque calculation unit 52, and an energization control unit 53.
The steering angle θa is input to the steering angle calculation unit 51. The steering angle calculation unit 51 counts the steering side rotation angle θa, for example, the number of rotations of the steering side motor 13 from the steering neutral position, which is the position of the steering wheel 3 when the vehicle is traveling straight, 360. Convert to an integrated angle that includes a range that exceeds the degree. The steering angle calculation unit 51 calculates the steering angle θs by multiplying the integrated angle obtained by conversion by a conversion coefficient based on the rotation speed ratio of the steering side deceleration mechanism 14. The steering angle θs is positive when the angle is on the right side of the steering neutral position, and negative when the angle is on the left side.

The target reaction torque calculation unit 52 has a steering torque Th, a vehicle speed value V, a steering angle θs, a steering side actual current value Ib, a target pinion angle θp * described later, a steering conversion angle θp_s described later, and a code described later. The signal Sm is input. The target reaction torque calculation unit 52 steers based on the steering torque Th, the vehicle speed value V, the steering angle θs, the steering side actual current value Ib, the target pinion angle θp *, the steering conversion angle θp_s, and the code signal Sm. The target reaction force torque Ts * as the target reaction force control amount of the steering reaction force of the steering wheel 3 to be generated through the side motor 13 is calculated.

Specifically, the target reaction force torque calculation unit 52 has a steering force calculation unit 55 and an axial force calculation unit 56.
The steering torque Th and the vehicle speed value V are input to the steering force calculation unit 55. The steering force calculation unit 55 calculates the steering force Tb * based on the steering torque Th and the vehicle speed value V. The steering force Tb * acts in the same direction as the driver's steering direction. The steering force calculation unit 55 calculates a steering force Tb * having a larger absolute value as the absolute value of the steering torque Th is larger and the vehicle speed value V is slower. The steering force Tb * is calculated as a value of the torque dimension (Nm). The steering force Tb * thus obtained is output to the subtractor 57.

A vehicle speed value V, a steering angle θs, a steering side actual current value Ib, a target pinion angle θp * described later, a steering conversion angle θp_s described later, and a code signal Sm described later are input to the axial force calculation unit 56. .. The axial force calculation unit 56 rolls based on the vehicle speed value V, the steering angle θs, the steering side actual current value Ib, the target pinion angle θp * described later, the steering conversion angle θp_s described later, and the code signal Sm described later. The axial force F acting on the rack shaft 22 through the steering wheel 5 is calculated. The axial force F is calculated as a value of the torque dimension (Nm). The axial force F acts in the direction opposite to the steering direction of the driver. The target reaction torque Ts * is calculated by subtracting the axial force F from the steering force Tb * by the subtractor 57. The target reaction force torque Ts * thus obtained is output to the energization control unit 53.

The target reaction force torque Ts *, the steering side rotation angle θa, and the steering side actual current value Ia are input to the energization control unit 53. The energization control unit 53 calculates the current command value Ia * for the steering side motor 13 based on the target reaction force torque Ts *. The energization control unit 53 obtains a deviation between the current command value Ia * and the current value on the dq coordinate obtained by converting the steering side actual current value Ia based on the steering side rotation angle θa, and eliminates the deviation. It controls the power supply to the steering side motor 13. The steering side motor 13 generates a torque corresponding to the target reaction force torque Ts *. This makes it possible to give the driver an appropriate feeling of response.

The function of the steering side control unit 60 will be described.
The steering side control unit 60 includes a pinion angle calculation unit 61, a steering angle ratio variable control unit 62, a pinion angle feedback control unit (“pinion angle F / B control unit” in FIG. 2) 63, and an energization control unit 64. And a rudder angle conversion unit 65, and a code signal generation unit 66.

The rotation angle θb on the steering side is input to the pinion angle calculation unit 61. The pinion angle calculation unit 61 counts the rotation speed of the steering side motor 33 from the rack neutral position, which is the position of the rack shaft 22 when the vehicle is traveling straight, for example, by counting the rotation angle θb of the steering side. Convert to an integrated angle that includes a range exceeding 360 degrees. The pinion angle calculation unit 61 multiplies the integrated angle obtained by conversion by a conversion coefficient based on the rotation speed ratio of the steering side deceleration mechanism 34, thereby multiplying the pinion angle, which is the actual rotation angle of the second pinion shaft 32. Calculate θp. The pinion angle θp is positive when the angle is on the right side of the rack neutral position, and negative when the angle is on the left side. The pinion angle θp thus obtained is output to the pinion angle feedback control unit 63. Further, the subtractor 68 calculates the after compensation pinion angle θp'by subtracting the drift state quantity θx from the pinion angle θp. The compensated pinion angle θp ′ thus obtained is output to the steering angle conversion unit 65.

The vehicle speed value V and the steering angle θs are input to the steering angle ratio variable control unit 62. The steering angle ratio variable control unit 62 calculates the target pinion angle θp * by adding the adjustment amount to the steering angle θs. The steering angle ratio variable control unit 62 changes the adjustment amount for changing the steering angle ratio, which is the ratio of the target pinion angle θp * to the steering angle θs, according to the vehicle speed value V. For example, the adjustment amount is varied so that the change in the target pinion angle θp * with respect to the change in the steering angle θs is larger than when the vehicle speed value V is fast. There is a correlation between the steering angle θs and the target pinion angle θp *. Further, the pinion angle θp is controlled based on the target pinion angle θp *. Therefore, there is also a correlation between the steering angle θs and the pinion angle θp.

The target pinion angle θp * and the pinion angle θp are input to the pinion angle feedback control unit 63. The pinion angle feedback control unit 63 executes PD control using a proportional term and a differential term as feedback control of the pinion angle θp so that the pinion angle θp follows the target pinion angle θp *. That is, the pinion angle feedback control unit 63 obtains the deviation between the target pinion angle θp * and the pinion angle θp, and the steering force command value T as the target control amount of the steering force so as to eliminate the deviation. * Is calculated.

The steering force command value T *, the steering side rotation angle θb, and the steering side actual current value Ib are input to the energization control unit 64. The energization control unit 64 calculates the current command value Ib * for the steering side motor 33 based on the steering force command value T *. Then, the energization control unit 64 obtains a deviation between the current command value Ib * and the current value on the dq coordinate obtained by converting the steering side actual current value Ib based on the steering side rotation angle θb, and obtains the deviation. The power supply to the steering side motor 33 is controlled so as to eliminate the above. As a result, the steering side motor 33 rotates by an angle corresponding to the steering force command value T *.

The vehicle speed value V and the compensated pinion angle θp'are input to the steering angle conversion unit 65. The steering angle conversion unit 65 calculates the steering conversion angle θp_s by adding the adjustment amount Δθ'to the corrected pinion angle θp'. The steering angle conversion unit 65 responds to the vehicle speed value V so that the adjustment amount Δθ'is an calculation rule in which the relationship between input and output is reversed with respect to the calculation rule defined by the steering angle ratio variable control unit 62. Make it variable. That is, if the steering angle ratio variable control unit 62 makes a larger change in the target pinion angle θp * with respect to a change in the steering angle θs than, for example, when the vehicle speed value V is slow, the steering angle conversion unit 65 Adjusts the adjustment amount Δθ'so that the change in the steering conversion angle θp_s with respect to the change in the post-compensated pinion angle θp'is smaller than when the vehicle speed value V is fast. As a result, the steering angle conversion unit 65 converts the compensated pinion angle θp'expressed as the value of the steering angle index so as to be expressed as the value of the steering angle index according to the steering angle ratio. The rudder conversion angle θp_s is calculated. The conversion angle described in the claims corresponds to the steering conversion angle θp_s. The steering conversion angle θp_s thus obtained is output to the axial force calculation unit 56.

A detection result of a temperature sensor or the like (not shown) is input to the code signal generation unit 66. The temperature sensor detects, for example, the temperature of the motor coil or the inverter of the steering side motor 33. In this case, the code signal generation unit 66 determines the heat generation state as the state of the steering side motor 33 by comparing the temperature detected by the temperature sensor with the plurality of temperature threshold values. The heat generation state of the steering side motor 33 is, in order from the one with the least need to limit the operation of the steering side motor 33, for example, a normal heat generation state, a mild overheating state, a moderate overheating state, and a severe overheating state. Overheated conditions are included. The normal heat generation state indicates that the operation of the steering side motor 33 is not restricted. On the other hand, a mild overheated state, a moderate overheated state, and a severe overheated state indicate that the operation of the steering side motor 33 is restricted.

Further, a detection result of a voltage sensor or the like (not shown) is input to the code signal generation unit 66. The voltage sensor detects the voltage of a DC power source such as a battery. In this case, the code signal generation unit 66 determines the state of the voltage of the DC power supply by comparing the voltage detected by the voltage sensor with the plurality of voltage threshold values. The voltage states of the DC power supply are, in order from the direction in which it is less necessary to limit the operation of the steering side motor 33, for example, a normal voltage state, a slight voltage drop state, a moderate voltage drop state, and a severe voltage state. Includes a down state. Then, the normal voltage state indicates that the operation of the steering side motor 33 is not limited. On the other hand, a slight voltage drop state, a moderate voltage drop state, and a severe voltage drop state indicate that the operation of the steering side motor 33 is restricted.

The code signal generation unit 66 executes the following processing when generating the code signal Sm. That is, the code signal generation unit 66 encodes the state of the steering device 2 according to the code table stored in the storage unit of the steering control device 1. The coding means a process of expressing the state of the steering device 2 with a code as a symbol. The state of the steering device 2 includes a heat generation state of the steering side motor 33 and a voltage state of the DC power supply. An example of the correspondence between the state of the steering device 2 and the cord is as follows.

-Code "0" ... Normal state where the operation of the steering side motor 33 is not restricted-Code "1A" ... Mild overheating state of the steering side motor 33-Code "1B" ... Medium of the steering side motor 33 Overheated state-Code "1C" ... Severe overheated state of the steering side motor 33-Code "2A" ... Slight voltage drop state of DC power supply-Code "2B" ... Moderate voltage drop state of DC power supply-Code "2A" 2C ”... Severe voltage drop state of DC power supply The code signal generation unit 66 generates a code signal Sm indicating a code corresponding to the state of the steering device 2. The code signal Sm thus obtained is output to the axial force calculation unit 56.

In the present embodiment, the steering side control unit 60 outputs the code signal Sm, which is a signal indicating the state of the steering device 2, to the steering side control unit 50, so that the state of the steering device 2, particularly the steering side motor 33. The state can be grasped by the steering side control unit 50. Here, if only the realization of having the steering side control unit 50 grasp the state of the steering side motor 33 is considered, various information such as the temperature of the steering side motor 33 and the voltage of the DC power supply is steered. This can also be realized by outputting the side control units 60 to the steering side control unit 50, respectively. In this respect, in the present embodiment, various information such as the temperature of the steering side motor 33 and the voltage of the DC power supply must be output as compared with the case where the steering side control unit 60 outputs each to the steering side control unit 50. It is advantageous in that the amount of information that should not be used can be reduced and the communication load between the steering side control unit 50 and the steering side control unit 60 can be reduced.

The temperature threshold is set to a value in a range experimentally obtained as a temperature at which the motor coil or the inverter is considered to be approaching an overheated state, for example. Further, the voltage threshold value is set to a value in a range experimentally obtained as a voltage considered to be approaching a state in which the DC power supply cannot sufficiently supply electric power, for example. The steering side control unit 60 executes control in a protection mode that limits the power supply to the steering side motor 33 in order to limit the operation of the steering side motor 33 in a state other than the normal heat generation state and the voltage state. do. On the other hand, the steering side control unit 60 executes control in a normal mode in which the operation of the steering side motor 33 is not restricted and the power supply to the steering side motor 33 is not restricted in the normal heat generation state and the voltage state. ..

Here, the function of the axial force calculation unit 56 will be described in more detail.
As shown in FIG. 3, the axial force calculation unit 56 includes a distribution axial force calculation unit 71, an end axial force calculation unit 72, a deviation axial force calculation unit 73, and an axial force selection unit 74.

The distribution axial force calculation unit 71 calculates the distribution axial force Fd according to the axial force acting on the rack shaft 22. The distributed axial force Fd is a rack obtained by distributing the angular axial force Fr and the current axial force Fi, which will be described later, in their respective distribution ratios so that the axial force acting on the rack shaft 22 through the steering wheel 5 is suitably reflected. It corresponds to the calculated axial force that estimates the axial force acting on the shaft 22. The distribution axial force Fd thus obtained is output to the adder 75.

The end axial force calculation unit 72 calculates an end axial force Fie that conveys the situation to the driver when the steering limit of the steering wheel 3, that is, the steering limit of the steering wheel 5 is reached. The end axial force Fie is used for steering in order to regulate further steering of the steering wheel 3 to the side exceeding the steering angle limit when the absolute value of the steering angle θs approaches the steering angle limit corresponding to the steering limit. It corresponds to the power to oppose it. The end axial force Fie thus obtained is output to the axial force selection unit 74.

The deviation axial force calculation unit 73 informs the driver of the situation when the relationship between the steering state of the steering wheel 3 and the steering state of the steering wheel 5 in consideration of the steering angle ratio becomes different. The deviation axial force Fv is calculated. The following situations can be mentioned as cases where a deviation occurs in the relationship in consideration of the steering angle ratio between the steering state of the steering wheel 3 and the steering state of the steering wheel 5. For example, power transmission between the steering unit 4 and the steering unit 6 even though the steering wheel 5 hits an obstacle such as a rim stone and the steering wheel 5 cannot be steered in one direction on the obstacle side. Since the roads are separated, there is a situation where the steering wheel 3 is steered in one direction beyond the stop position of the steering wheel 3 corresponding to the stop position of the steering wheel 5. In addition, as a result of the operation of the steering side motor 33 being restricted due to overheat protection, it becomes difficult for the pinion angle θp to follow the target pinion angle θp *, so that between the steering angle θs and the steering angle. There is a situation where the correlation is broken. The deviation axial force Fv corresponds to a force that opposes the steering wheel 3 in order to regulate further steering when the steering wheel 5 hits an obstacle such as a curb. Further, when the operation of the steering side motor 33 is restricted due to overheat protection, the steering of the steering wheel 3 is regulated in order to ensure the followability of the pinion angle θp to the target pinion angle θp *. It corresponds to the power to oppose it. The deviation axial force Fv thus obtained is output to the axial force selection unit 74.

The end axial force Fie and the deviation axial force Fv are input to the axial force selection unit 74. The axial force selection unit 74 selects the axial force having the largest absolute value among the end axial force Fie and the deviation axial force Fv, and calculates the selected axial force as the selected axial force Fsl. The axial force F is calculated by adding the selected axial force Fsl to the distributed axial force Fd in the adder 75. The axial force F thus obtained is output to the subtractor 57. The subtractor 57 calculates the target reaction force torque Ts * by subtracting the distributed axial force Fd from the steering force Tb *. The target reaction force torque Ts * thus obtained is output to the energization control unit 53.

Next, the function of the distribution axial force calculation unit 71 will be described in detail.
As shown in FIG. 4, the distribution axial force calculation unit 71 includes an angle axial force calculation unit 81, a current axial force calculation unit 82, and a distribution ratio calculation unit 83.

The target pinion angle θp * and the vehicle speed value V are input to the angle axial force calculation unit 81. The angle axis force calculation unit 81 calculates the angle axis force Fr based on the target pinion angle θp * and the vehicle speed value V. The angular axial force Fr is an ideal value of the axial force defined by the model of the vehicle set arbitrarily. The angular axial force Fr is calculated as an axial force that does not reflect the road surface information. The road surface information is information such as minute irregularities that do not affect the lateral behavior of the vehicle and steps that affect the lateral behavior of the vehicle. Specifically, the angle axis force calculation unit 81 calculates so that the larger the absolute value of the target pinion angle θp *, the larger the absolute value of the angle axis force Fr. Further, the angle axial force calculation unit 81 calculates so that the absolute value of the angle axial force Fr increases as the vehicle speed value V increases. The angular axial force Fr is calculated as a value of the torque dimension (Nm). The angular axial force Fr thus obtained is output to the multiplier 84.

The actual current value Ib on the steering side is input to the current axial force calculation unit 82. The current axial force calculation unit 82 calculates the current axial force Fi based on the actual current value Ib on the steering side. The current axial force Fi is an estimated value of the axial force actually acting on the rack shaft 22 that operates to steer the steering wheel 5, that is, the axial force actually transmitted to the rack shaft 22. The current axial force Fi is calculated as an axial force that reflects the road surface information. Specifically, the current axial force calculation unit 82 steers on the assumption that the torque applied to the rack shaft 22 by the steering side motor 33 and the torque corresponding to the force applied to the rack shaft 22 through the steering wheel 5 are balanced. The calculation is performed so that the larger the absolute value of the side actual current value Ib, the larger the absolute value of the current axial force Fi. The current axial force Fi is calculated as a value of the torque dimension (Nm). The current axial force Fi thus obtained is output to the multiplier 85.

The vehicle speed value V is input to the distribution ratio calculation unit 83. The distribution ratio calculation unit 83 calculates the distribution gain Di based on the vehicle speed value V. The distribution gain Di is the distribution ratio of the current axial force Fi when the angular axial force Fr and the current axial force Fi are distributed to obtain the axial force F. Specifically, the distribution ratio calculation unit 83 includes a distribution gain map that defines the relationship between the vehicle speed value V and the distribution gain Di, and performs map calculation of the distribution gain Di with the vehicle speed value V as an input.

The distribution gain Di is "1 (100%)" when the vehicle speed value V is a low vehicle speed including a stop. In this case, at a low vehicle speed, it is shown that only the current axial force Fi is distributed to the axial force F, that is, the angular axial force Fr is not distributed. Further, the distribution gain Di becomes a "zero value (0%)" when the vehicle speed value V is a high vehicle speed such as, for example, 60 km / h or more. In this case, at high vehicle speeds, it is shown that only the angular axial force Fr is distributed to the axial force F, that is, the current axial force Fi is not distributed. That is, the distribution ratio of the present embodiment includes the concept of a zero value in which only one of the angular axial force Fr and the current axial force Fi is allocated to the axial force F.

The distribution gain Di thus obtained is multiplied by the current axial force Fi obtained by the current axial force calculation unit 82 and output to the adder 88 as the final current axial force Fim obtained through the multiplier 85. Further, the subtractor 86 calculates the distribution gain Dr by subtracting the distribution gain Di from the “1” stored in the storage unit 87. The distribution gain Dr thus obtained is output to the multiplier 84. The distribution gain Dr is the distribution ratio of the angle axial force Fr when the angular axial force Fr and the current axial force Fi are distributed to obtain the axial force F. That is, the value of the distribution gain Dr is calculated so that the sum with the distribution gain Di is "1 (100%)". The storage unit 87 is a predetermined storage area of a memory (not shown).

The distribution gain Dr thus obtained is output to the adder 88 as the final angle axial force Frm obtained through the multiplier 84 by multiplying the angle axial force Fr obtained by the angle axial force calculation unit 81. Further, the angular axial force Frm thus obtained is added to the current axial force Fim and output to the adder 75 as the distributed axial force Fd obtained through the adder 88.

The function of the end axial force calculation unit 72 will be described in detail.
As shown in FIG. 3, the target pinion angle θp * is input to the end axial force calculation unit 72. The end axial force calculation unit 72 calculates the end axial force Fie based on the target pinion angle θp *. Specifically, the end axial force calculation unit 72 has an end axial force map that defines the relationship between the target pinion angle θp * and the end axial force Fie, and the end axis is input with the target pinion angle θp *. Map the force Fie. When the absolute value of the target pinion angle θp * is equal to or less than the threshold angle θie, the end axial force calculation unit 72 calculates the end axial force Fie as “0”. When the absolute value of the target pinion angle θp * is larger than the threshold angle θie, the end axial force calculation unit 72 calculates the end axial force Fie whose absolute value is larger than “0”. The end axial force Fie is set so that when the absolute value of the target pinion angle θp * exceeds the threshold angle θie and becomes large to some extent, the absolute value becomes so large that the steering wheel 3 cannot be steered further by human hands. ing. The end axial force Fie thus obtained is output to the axial force selection unit 74.

Next, the function of the deviation axial force calculation unit 73 will be described in detail.
As shown in FIG. 5, the deviation axial force calculation unit 73 includes an axial force basic component calculation unit 101, an axial force viscosity component calculation unit 102, a gradual change processing unit 103, an upper limit guard processing unit 104, and a code processing unit. It has 105.

The deviation Δθ obtained by subtracting the steering conversion angle θp_s from the steering angle θs and the code signal Sm are input to the axial force basic component calculation unit 101. The axial force basic component calculation unit 101 calculates the axial force basic component FΔθ based on the deviation Δθ and the code signal Sm. Specifically, the axial force basic component calculation unit 101 includes an axial force basic component map that defines the relationship between the absolute value of the deviation Δθ and the axial force basic component FΔθ, and the axial force is input with the deviation Δθ as an input. Map the basic component FΔθ. The reference angle described in the claims corresponds to the steering angle θs.

In the present embodiment, the axial force basic component calculation unit 101 includes two types of maps as the axial force basic component map. The axial force basic component calculation unit 101 calculates the axial force basic component FΔθ using either one of the two types of maps based on the code signal Sm. The axial force basic component calculation unit 101 indicates a code "0" which is a normal state in which the operation of the steering side motor 33 is not restricted, that is, when a code signal Sm indicating that the normal mode is executed is input, in FIG. , Perform map calculation using the axial force basic component map for normal mode shown by the alternate long and short dash line. In FIG. 5, the axial force basic component map for the normal mode shown by the alternate long and short dash line shows the case where the absolute value of the deviation Δθ is less than the first deviation threshold Δθ1 when the absolute value of the deviation Δθ reaches the first deviation threshold Δθ1 or more. The gradient of the axial force basic component FΔθ with respect to the deviation Δθ is set to be larger than that of the above. That is, when the code signal Sm indicating that the normal mode is executed is input, the axial force basic component calculation unit 101 sets the axial force basic component FΔθ to “0” when the absolute value of the deviation Δθ is less than the first deviation threshold value Δθ1. When the absolute value of the deviation Δθ reaches the first deviation threshold Δθ1 or more, the axial force basic component FΔθ whose absolute value is larger than “0” is calculated. The axial force basic component FΔθ obtained through the axial force basic component map for the normal mode corresponds to the first deviation axial force component.

The axial force basic component calculation unit 101 is input with a code signal Sm indicating a state other than the code "0", which is a state other than the normal state in which the operation of the steering side motor 33 is restricted, that is, indicating that the protection mode is executed. And, in FIG. 5, the map calculation using the axial force basic component map for the protection mode shown by the solid line is performed. In FIG. 5, the axial force basic component map for the protection mode shown by the solid line is compared with the case where the absolute value of the deviation Δθ is less than the second deviation threshold Δθ2 when the absolute value of the deviation Δθ reaches the second deviation threshold Δθ2 or more. Therefore, the gradient of the axial force basic component FΔθ with respect to the deviation Δθ is set to be large. That is, when the code signal Sm indicating that the protection mode is executed is input, the axial force basic component calculation unit 101 sets the axial force basic component FΔθ to “0” when the absolute value of the deviation Δθ is less than the second deviation threshold Δθ2. When the absolute value of the deviation Δθ reaches the second deviation threshold Δθ2 or more, the axial force basic component FΔθ whose absolute value is larger than “0” is calculated. The axial force basic component FΔθ obtained through the axial force basic component map for the protection mode corresponds to the second deviation axial force component. The axial force basic component FΔθ thus obtained is output to the gradual change processing unit 103.

In the present embodiment, the second deviation threshold value Δθ2 is set as a value smaller than the first deviation threshold value Δθ1. That is, the axial force basic component map used for the map calculation in the situation where the normal mode is executed has a shape in which the map used for the map calculation in the situation where the protection mode is executed is translated in the direction in which the deviation Δθ increases. As a result, in the axial force basic component map used for the map calculation in the situation where the normal mode is executed, the dead zone of the deviation Δθ is set larger than that in the axial force basic component map used for the map calculation in the situation where the protection mode is executed. .. That is, in the situation where the normal mode is executed, the situation where the gradient of the axial force basic component FΔθ with respect to the deviation Δθ becomes larger than the situation where the protection mode is executed appears in the situation where the deviation Δθ becomes larger. .. This is because, in the normal mode, if the deviation axial force Fv is calculated according to the minute deviation Δθ, the steering operation of the driver may be hindered.

In particular, in this embodiment, since PD control is adopted as the pinion angle feedback control unit 63 and there is no integral term, a small deviation between the target pinion angle θp * and the pinion angle θp may remain as compared with the PID control. There is sex. If a small deviation between the target pinion angle θp * and the pinion angle θp remains, a small deviation Δθ may occur due to this. Therefore, if the dead zone is set to the same size in the protection mode and the normal mode, it is conceivable that the deviation axial force Fv may frequently occur at the stage where the deviation Δθ is small in the normal mode. As a result, the driver's steering operation may be hindered in the normal mode. However, as in the present embodiment, the dead zone in the normal mode is set to be larger than the dead zone in the protection mode, so that the frequency at which the deviation axial force Fv occurs at the stage where the deviation Δθ is small even in the normal mode. It is possible to suppress the situation in which the driver is hindered by the deviation axial force Fv in the normal mode.

Axial force basic component FΔθ and a code signal Sm are input to the gradual change processing unit 103. The gradual change processing unit 103 refers to the axial force basic component FΔθ when the content indicated by the code signal Sm is switched between the code “0” and other than the code “0”, that is, between the normal mode and the protection mode. , Perform a gradual change process over time. Specifically, when the mode is switched between the normal mode and the protection mode, the gradual change processing unit 103 determines the deviation of the axial force basic component FΔθ after switching from the axial force basic component FΔθ calculated before the switching. It is acquired and the deviation is calculated as an offset amount. In this case, the gradual change processing unit 103 calculates the post-processing axial force basic component FΔθ'by shifting the axial force basic component FΔθ after switching to the axial force basic component FΔθ side before switching by an offset amount. Then, the gradual change processing unit 103 executes a gradual change process in which the offset amount is gradually reduced so that the axial force basic component FΔθ after switching becomes the original value after switching. As a result, even when the mode is switched between the normal mode and the protection mode, the post-processing axial force basic component FΔθ'is suppressed from suddenly changing. If the offset amount does not exist while the content indicated by the code signal Sm is not switched between the normal mode and the protection mode, the gradual change processing unit 103 processes the axial force basic component FΔθ and then performs the axial force basis. Calculated as the component FΔθ'. In the present embodiment, the axial force basic component calculation unit 101 and the gradual change processing unit 103 correspond to the deviation axial force component calculation unit. Further, in the present embodiment, the post-processed axial force basic component FΔθ'corresponds to the deviation axial force component. The post-process axial force basic component FΔθ ′ thus obtained is output to the adder 107.

The steering angular velocity ωs obtained through the differentiator 108 by differentiating the steering angle θs is input to the axial force viscosity component calculation unit 102. The steering angular velocity ωs is set as information indicating the amount of change in the steering angle θs. Specifically, the axial force viscous component calculation unit 102 includes an axial force viscous component map that defines the relationship between the absolute value of the steering angular velocity ωs and the axial force viscous component Fω, and obtains the absolute value of the steering angular velocity ωs. As an input, a map calculation is performed on the axial force viscosity component Fω. The angular velocity described in the claims corresponds to the steering angular velocity ωs.

When the absolute value of the steering angular velocity ωs is large, the axial force viscosity component calculation unit 102 calculates the axial force viscosity component Fω having a larger absolute value than when the absolute value of the steering angular velocity ωs is small. The axial force viscosity component Fω is set to have a larger absolute value as the steering angular velocity ωs increases. The axial force viscosity component Fω functions to suppress a sudden change in the axial force basic component FΔθ. That is, the axial force viscosity component Fω functions to moderate the rise of the deviation axial force Fv calculated by using the axial force basic component FΔθ. As a result, the feeling of elasticity of the tire when the steering wheel 5 hits an obstacle, the feeling of viscosity of the tire when the steering wheel 5 steers, and the feeling of rigidity of the mechanical configuration from the steering wheel 5 to the steering wheel 3 I am trying to reproduce. When the deviation Δθ is less than the deviation threshold value, that is, when the axial force basic component FΔθ is “0”, the axial force viscosity component calculation unit 102 uses the calculated axial force viscosity component Fω as the axial force basic component. The axial force viscosity component Fω is output as “0” so as not to be reflected in FΔθ.

In the adder 107, the total axial force Ft is calculated by adding the axial force viscosity component Fω to the post-processed axial force basic component FΔθ ′. The total axial force Ft thus obtained is output to the upper limit guard processing unit 104. The vehicle speed value V, the total axial force Ft, and the maximum value Flim stored in the storage unit 109 are input to the upper limit guard processing unit 104. The storage unit 109 is a predetermined storage area of a memory (not shown). The maximum value Flim is experimentally obtained as an index that can secure the maximum total axial force Ft while the vehicle speed value V does not affect the steering of the steering wheel 3 in the case of the above high vehicle speed, for example. The value in the range is set.

When the vehicle speed value V is, for example, less than the vehicle speed threshold value indicating that the vehicle speed is low, the upper limit guard processing unit 104 outputs the total axial force Ft as the total axial force Ft'after guarding. Further, when the vehicle speed value V is, for example, the vehicle speed threshold value indicating that the vehicle speed is high or higher, the upper limit guard processing unit 104 executes the upper limit guard processing for the total axial force Ft. When the total axial force Ft is less than the maximum value Flim while executing the upper limit guard process, the upper limit guard processing unit 104 outputs the total axial force Ft as the total axial force Ft'after guarding. Further, when the total axial force Ft is equal to or greater than the maximum value Flim while executing the upper limit guard process, the upper limit guard processing unit 104 outputs the maximum value Flim as the total axial force Ft'after guarding. The total axial force Ft'after guarding thus obtained is output to the multiplier 110.

The actual current value Ib on the steering side is input to the code processing unit 105. The sign processing unit 105 sets the sign of the total axial force Ft'after guarding based on the actual current value Ib on the steering side. That is, the code processing unit 105 outputs "+1" when the actual current value Ib on the steering side is a positive value including a zero value, and "-1" when the actual current value Ib on the steering side is a negative value. Output. The value of "1" or "-1" thus obtained is multiplied by the total axial force Ft'after guarding and output to the axial force selection unit 74 as the deviation axial force Fv obtained through the multiplier 110.

The operation of the first embodiment will be described.
The situation of the steering wheel 5 is reflected in the pinion angle θp obtained as information of the steering unit 6. For example, in a situation where the steering wheel 5 hits an obstacle, the pinion angle θp cannot change from the pinion angle θp when the steering wheel 5 hits the obstacle to the obstacle side. On the other hand, the situation of the steering wheel 3 is reflected in the steering angle θs obtained as information of the steering unit 4. For example, in a situation where the steering wheel 5 hits an obstacle, the steering angle θs is a steering wheel unless an axial force for informing the driver of the situation where the steering wheel 5 hits an obstacle is applied as a steering reaction force. The steering angle θs when 5 hits an obstacle can be further changed to the obstacle side. Therefore, the relationship between the steering angle θs and the pinion angle θp may be different. The present inventors have set an axial force for transmitting the situation in which the steering wheel 5 hits an obstacle to the driver, or a situation in which the steering wheel 5 is different from the situation in which the steering wheel 5 hits an obstacle. It was decided to pay attention to the common point that the relationship between the steering angle θs and the pinion angle θp is deviated for some reason when other types of axial forces are set. That is, if the present inventors determine the steering reaction force so that the deviation between the steering angle θs and the pinion angle θp does not increase or is eliminated for some reason, there are a plurality of types. It was discovered that the axial force of can be considered collectively.

Specifically, in the present embodiment, the deviation axial force Fv is calculated based on the deviation Δθ between the steering angle θs and the steering conversion angle θp_s. In this case, assuming that the steering angle ratio changes, the deviation Δθ between the steering angle θs and the steering conversion angle θp_s is taken into consideration that the steering angle θs and the pinion angle θp do not correspond one-to-one. In the calculation, a configuration is adopted in which the pinion angle θp is converted into the steering angle θs according to the steering angle ratio. As a result, the deviation Δθ between the steering angle θs and the steering conversion angle θp_s is calculated as a deviation in consideration of the steering angle ratio at that time when there is a deviation in the relationship between the steering angle θs and the pinion angle θp. Will be able to. Then, if the axial force basic component FΔθ, that is, the deviation axial force Fv is set based on the deviation Δθ between the steering angle θs and the steering conversion angle θp_s, a plurality of types of axial forces can be considered together. It is no longer necessary to individually set the axial force for each situation in which the above is to be generated.

The effect of the first embodiment will be described.
(1-1) Individually for each situation where axial force should be generated, such as a situation where the steering wheel 5 hits an obstacle such as a curb, or a situation where the output of the steering side motor 33 is restricted due to overheat protection. Since it is not necessary to set the axial force each time, it is possible to prevent the setting of the axial force to be considered for determining the steering reaction force from becoming complicated.

(1-2) Since the axial force viscous component Fω is calculated so that the larger the absolute value of the steering angular velocity ωs is, the smaller the change amount of the axial force basic component FΔθ is, it is possible to suppress the sudden change in the deviation axial force Fv. become able to. In this case, the feeling of elasticity of the tire when the steering wheel 5 hits an obstacle, the feeling of viscosity of the tire when the steering wheel 5 is steered, and the feeling of rigidity of the mechanical configuration from the steering wheel 5 to the steering wheel 3. By transmitting the steering reaction force to the driver, such as by reproducing the above, it is possible to more accurately convey the situation actually occurring on the steering wheel 5. Regarding the sense of rigidity of the mechanical configuration from the steering wheel 5 to the steering wheel 3, the sense of rigidity when the power transmission path between the steering portion 4 and the steering portion 6 is connected is reproduced. May be good. In this case, while transmitting the steering reaction force to the driver, the steering wheel 5 has the same rigidity as in the case where the steering device 2 is a steering device in which the steering unit 4 and the steering unit 6 are always mechanically connected. Can be reproduced. Further, it is possible to moderate the return of the steering wheel 3 to the neutral position, which occurs when the driver releases the steering wheel 3 or reduces the force for holding the steering wheel 3.

(1-3) It is conceivable that the actual turning behavior of the vehicle deviates from the ideal turning behavior of the vehicle in the running state during turning. The actual turning behavior of the vehicle includes an understeer state and an oversteer state. Therefore, according to the present embodiment, the deviation axial force calculation unit 73 calculates the deviation Δθ using the compensated pinion angle θp ′ compensated based on the drift state quantity θx. As a result, for example, in the oversteer state, the steering reaction force is adjusted so as to inform the driver that the pinion angle θp is slightly smaller than that of the steering wheel 5. Can be widened.

(1-4) The steering angle θs and the steering conversion angle θp_s are due to the change in the followability of the pinion angle θp depending on whether or not the operation of the steering side motor 33 is restricted. It is conceivable that the appearance of the magnitude of the deviation Δθ between the two will change. In this case, depending on whether or not the operation of the steering side motor 33 is restricted, the axial force basic component FΔθ obtained through the axial force basic component map for the normal mode and the axial force basis for the protection mode Which of the axial force basic components FΔθ obtained through the component map is added to the deviation axial force Fv is switched. Thereby, an appropriate deviation axial force Fv can be calculated depending on whether or not the operation of the steering side motor 33 is restricted.

(1-5) When switching the axial force basic component map for calculating the axial force basic component due to the switching of whether or not the operation of the steering side motor 33 is restricted, there is a difference before and after the switching. If present, the difference can be gradually reduced. As a result, sudden changes in the deviation axial force Fv can be suppressed depending on whether or not the operation of the steering side motor 33 is not restricted.

(1-6) In the situation where the protection mode is executed, the deviation Δθ between the steering angle θs and the steering conversion angle θp_s is less likely to increase due to the decrease in the followability of the pinion angle θp. , It becomes possible to deal with the deviation Δθ while it is small.

(1-7) In the situation where the normal mode is executed, the situation where the gradient of the axial force basic component FΔθ with respect to the deviation Δθ becomes larger does not appear unless the deviation Δθ becomes large to some extent, and the deviation Δθ does not appear. It is configured so that the dead zone of is large. As a result, in the situation where the normal mode is executed, the deviation axial force Fv is calculated according to the minute deviation Δθ, and it is possible to suppress the driver's steering operation from being hindered.

(1-8) When the target pinion angle θp * exceeds the threshold angle θie, the end axial force calculation unit 72 determines that the steering angle θs exceeds the steering angle limit, and sets the target pinion angle θp *. The end axial force Fie is calculated based on this. When the steering angle θs exceeds the steering angle limit, the steering wheel 5 is turned in one direction on the side where the steering wheel 3 exceeds the steering angle limit by setting the end axial force Fie separately from the deviation axial force Fv. It will be possible to regulate the steering that steers the steering wheel. Thereby, for example, when the steering wheel 3 reaches the steering angle limit, the steering of the steering wheel 3 is restricted regardless of the magnitude of the deviation Δθ between the steering angle θs and the steering conversion angle θp_s. be able to.

(1-9) There is a situation where the deviation axial force Fv and the end axial force Fie are calculated as values that should generate the steering reaction force at the same time, but even in such a situation, the target reaction force torque Ts * is actually obtained. It is the only axial force with the largest absolute value as the axial force reflected. Therefore, even in a situation where the deviation axial force Fv and the end axial force Fie are calculated as values that should generate the steering reaction force at the same time, it is possible to suppress the steering reaction force from becoming excessively large.

(1-10) The steering side control unit 60 provided with the steering angle ratio variable control unit 62 has a steering angle conversion unit 65. In this case, the function of converting using the steering angle ratio can be integrated in the steering side control unit 60, and a configuration that is easy to design when designing each control unit can be realized.

(1-11) When the vehicle is traveling at the high vehicle speed, for example, if the deviation axial force Fv becomes too large, the steering of the steering wheel 3 may be affected. According to the present embodiment, the upper limit guard processing unit 104 totals when the vehicle speed value V is equal to or higher than the vehicle speed threshold value, for example, when the vehicle is traveling at the high vehicle speed and the total axial force Ft is equal to or higher than the maximum value Flim. The axial force Ft is guarded by the maximum value Flim. As a result, when the vehicle is traveling at the high vehicle speed, for example, it is possible to prevent the deviation axial force Fv from affecting the steering of the steering wheel 3.

(1-12) Since it is only necessary to set the relationship of the deviation axial force Fv with respect to the deviation Δθ, the storage capacity of the ROM or the like of the steering control device 1 is larger than that in the case where the axial force is individually set for each relationship. It can be suppressed from becoming large.

<Second Embodiment>
A second embodiment of the steering control device will be described with reference to the drawings. Here, the differences from the first embodiment will be mainly described. Further, with respect to the same configuration as that of the first embodiment, the same reference numerals are given and the duplicated description thereof will be omitted.

As shown in FIG. 6, the deviation axial force calculation unit 73 of the present embodiment replaces the axial force basic component calculation unit 101 and the gradual change processing unit 103 of the first embodiment with the first deviation axial force component calculation. It has a unit 111, a second deviation axial force component calculation unit 112, and a distribution ratio calculation unit 113.

The deviation Δθ obtained through the subtractor 106 by subtracting the steering conversion angle θp_s from the steering angle θs is input to the first deviation axial force component calculation unit 111. The first deviation axial force component calculation unit 111 calculates the first deviation axial force component FΔθ1 based on the deviation Δθ. The first deviation axial force component calculation unit 111 includes a map showing the same tendency as the axial force basic component map for the normal mode shown by the alternate long and short dash line in FIG. 5, and the deviation Δθ is used as an input to obtain the first deviation axial force component calculation unit 111. 1 Map calculation is performed on the deviation axial force component FΔθ1. The first deviation axial force component FΔθ1 thus obtained is output to the multiplier 114.

The deviation Δθ obtained through the subtractor 106 by subtracting the steering conversion angle θp_s from the steering angle θs is input to the second deviation axial force component calculation unit 112. The second deviation axial force component calculation unit 112 calculates the second deviation axial force component FΔθ2 based on the deviation Δθ. The second deviation axial force component calculation unit 112 includes a map showing the same tendency as the axial force basic component map for the protection mode shown by the solid line in FIG. 5, and the second deviation is input with the deviation Δθ as an input. Map calculation is performed on the axial force component FΔθ2. The second deviation axial force component FΔθ2 thus obtained is output to the multiplier 115.

The code signal Sm is input to the distribution ratio calculation unit 113. The distribution ratio calculation unit 113 calculates the first distribution gain D1 based on the code signal Sm. The first distribution gain D1 is the first deviation axial force when the first deviation axial force component FΔθ1 and the second deviation axial force component FΔθ2 are distributed to obtain the deviation axial force component FΔθm which is summed up by a predetermined distribution ratio described later. It is the distribution ratio of the component FΔθ1.

The first distribution gain D1 thus obtained is the final first deviation axial force component obtained through the multiplier 114 by multiplying the first deviation axial force component FΔθ1 obtained by the first deviation axial force component calculation unit 111. It is output to the adder 116 as FΔθ1m. Further, the subtractor 117 calculates the second distribution gain D2 by subtracting the first distribution gain D1 from the "1" stored in the storage unit 118. The second distribution gain D2 thus obtained is output to the multiplier 115. The second distribution gain D2 is the second deviation axial force when the first deviation axial force component FΔθ1 and the second deviation axial force component FΔθ2 are distributed to obtain the deviation axial force component FΔθm which is summed up by the predetermined distribution ratio described later. It is the distribution ratio of the component FΔθ2. The value of the second distribution gain D2 is calculated so that the sum with the first distribution gain D1 is "1 (100%)". The distribution ratio between the first distribution gain D1 and the second distribution gain D2 is set to an appropriate value depending on the situation limiting the operation of the steering side motor 33, the product specifications, and the like. The storage unit 118 is a predetermined storage area of a memory (not shown).

The second distribution gain D2 thus obtained is the final second deviation axial force component obtained through the multiplier 115 by multiplying the second deviation axial force component FΔθ2 obtained by the second deviation axial force component calculation unit 112. It is output to the adder 116 as FΔθ2m. Further, the second deviation axial force component FΔθ2m thus obtained is output to the adder 107 as a deviation axial force component FΔθm which is added to the first deviation axial force component FΔθ1m and added up at a predetermined distribution ratio obtained through the adder 116. To.

In the present embodiment, the first deviation axial force component calculation unit 111, the second deviation axial force component calculation unit 112, the distribution ratio calculation unit 113, the multipliers 114 and 115, the adder 116, and the subtractor 117 , The storage unit 118 corresponds to the deviation axial force component calculation unit.

Next, the distribution ratio calculation unit 113 will be described in detail. A specific setting example of the distribution ratio between the first distribution gain D1 and the second distribution gain D2 is as follows.
When the code signal Sm indicating the code "0" is input to the distribution ratio calculation unit 113, that is, in a normal state where the operation of the steering side motor 33 is not restricted, the distribution gains D1 and D2 have the following relational expressions. The distribution gain D1 is calculated so that the distribution ratio is represented by (1).

D1: D2 = 1 (100%): 0 (0%) ... (1)
In this case, the first distribution gain D1 is set to "1 (100%)" and the second distribution gain D2 is set to "zero value (0%)". Therefore, when the code signal Sm indicating the code "0" is input, the first deviation axial force of the first deviation axial force component FΔθ1 and the second deviation axial force component FΔθ2 with respect to the deviation axial force Fv. It is shown that only the component FΔθ1 is added, that is, the second deviation axial force component FΔθ2 is not added. That is, the distribution ratio of the present embodiment includes the concept of a zero value in which only one of the first deviation axial force component FΔθ1 and the second deviation axial force component FΔθ2 is added to the deviation axial force Fv.

In the distribution ratio calculation unit 113, the more the overheated state indicated by the code signal Sm changes in the order of “mild”, “moderate”, and “severe”, that is, the more the steering side motor 33 is in the overheated state, the more the first distribution gain is obtained. Set D1 to a small value. In this case, the second distribution gain D2 is set to a larger value as the superheat state indicated by the code signal Sm changes in the order of "mild", "moderate", and "severe".

When the code signal Sm indicating the code "1A" is input to the distribution ratio calculation unit 113, that is, when the steering side motor 33 is in a slightly overheated state, the distribution gains D1 and D2 are the following relational expressions (2). ), The distribution gain D1 is calculated so as to be the distribution ratio.

D1: D2 = 0.8 (80%): 0.2 (20%) ... (2)
When the code signal Sm indicating the code "1B" is input to the distribution ratio calculation unit 113, that is, when the steering side motor 33 is in a moderately overheated state, the distribution gains D1 and D2 have the following relational expressions ( The distribution gain D1 is calculated so that the distribution ratio is represented by 3).

D1: D2 = 0.2 (20%): 0.8 (80%) ... (3)
When the code signal Sm indicating the code "1C" is input to the distribution ratio calculation unit 113, that is, when the steering side motor 33 is in a severe overheated state, the distribution gains D1 and D2 are the following relational expressions (4). ), The distribution gain D1 is calculated so as to be the distribution ratio.

D1: D2 = 0 (0%): 1 (100%) ... (4)
The distribution ratio calculation unit 113 sets the first distribution gain D1 to a smaller value as the voltage drop state of the DC power supply indicated by the code signal Sm changes in the order of "mild", "medium", and "severe". You may. In this case, when the code signal Sm indicating the code "2A" is input, the distribution ratio calculation unit 113 has the same distribution ratio as when the code signal Sm indicating the code "1A" is input. , The distribution gain D1 is calculated. Further, when the code signal Sm indicating the code "2B" is input, the distribution ratio calculation unit 113 has the same distribution ratio as when the code signal Sm indicating the code "1B" is input. Calculate the distribution gain D1. When the code signal Sm indicating the code "2C" is input, the distribution ratio calculation unit 113 has a distribution gain so as to have the same distribution ratio as when the code signal Sm indicating the code "1C" is input. Calculate D1.

The distribution ratio calculation unit 113 has a function of gradually changing the distribution gain D1 when the distribution gain D1 is changed. When the distribution ratio calculation unit 113 changes the distribution gain D1, the distribution ratio calculation unit 113 executes a gradual change process with respect to the time for the distribution gain D1. Specifically, when the code is switched, the distribution ratio calculation unit 113 gradually changes the distribution gain D1 from the value before the switch to the value after the switch with respect to the elapsed time. As a method for gradually changing the distribution gain D1, for example, the same method as the gradual change processing unit 103 of the first embodiment may be used. In this case, when the code is switched, the distribution ratio calculation unit 113 acquires the deviation of the distribution gain D1 after the switching from the distribution gain D1 calculated before the switching, and calculates the deviation as the offset amount. Further, the distribution ratio calculation unit 113 calculates the distribution gain D1 after processing by shifting the distribution gain D1 after switching to the distribution gain D1 side before switching by an offset amount. Then, the distribution ratio calculation unit 113 gradually reduces the offset amount with respect to time, and changes the distribution gain D1 after switching to the original value after switching.

According to this embodiment, the action and effect are similar to those of the first embodiment. Further, according to the present embodiment, the following effects are obtained.
(2-1) The distribution ratio between the first deviation axial force component FΔθ1 and the second deviation axial force component FΔθ2 is changed according to whether or not the operation of the steering side motor 33 is restricted. There is. Thereby, an appropriate deviation axial force Fv can be calculated depending on whether or not the operation of the steering side motor 33 is restricted.

(2-2) Due to the fact that the situation is such that the operation of the steering side motor 33 is restricted or not, the change can be gradually reflected when the distribution ratio is changed. As a result, sudden changes in the deviation axial force Fv can be suppressed depending on whether or not the operation of the steering side motor 33 is not restricted.

Each of the above embodiments may be modified as follows. In addition, the following other embodiments can be combined with each other to the extent that they are technically consistent.
In each of the above embodiments, the steering angle conversion unit 65 may be set as a function of the steering side control unit 50. Further, the steering angle ratio variable control unit 62 may be set in combination with the function of the steering angle conversion unit 65 as a function of the steering side control unit 50. In this case, the effect according to the effect (1-10) of the first embodiment can be obtained.

-In each of the above embodiments, the axial force selection unit 74 may be deleted. In this case, for example, the axial force F is calculated by the distributed axial force Fd calculated by the distributed axial force calculation unit 71, the end axial force Fie calculated by the end axial force calculation unit 72, and the deviation axial force calculation unit 73. It can be obtained through the adder 75 by adding the deviation axial force Fv.

In each of the above embodiments, the axial force calculation unit 56 is an additional shaft for transmitting the status of the steering wheel 5 in addition to the distribution axial force calculation unit 71, the end axial force calculation unit 72, and the deviation axial force calculation unit 73. It may have a function of calculating a force. In this case, the axial force selection unit 74 selects the axial force having the largest absolute value among the end axial force Fie, the deviation axial force Fv, and the additional axial force, and calculates the selected axial force as the selected axial force Fsl. do.

In each of the above embodiments, the host control device 45 generates a drift state quantity θx as a value having a dimension in an angle as a swivel state quantity, but is not limited to this, and has, for example, a torque dimension as a swivel state quantity. A drift state quantity may be generated. In this case, the drift state quantity having the torque dimension is converted into a value having the angle dimension, and then converted into the steering angle as the compensated pinion angle θp'obtained from the pinion angle θp by the subtractor 68. It is output to the unit 65.

In each of the above embodiments, the function of calculating the drift state quantity θx may be set as a function of the steering control device 1, that is, the steering side control unit 50 or the steering side control unit 60.
-In each of the above embodiments, the drift state quantity θx generated by the host control device 45 may not be input to the steering control device 1. In this case, the steering side control unit 60 can delete the subtractor 68. That is, in the steering angle conversion unit 65, the pinion angle θp calculated by the pinion angle calculation unit 61 is input, and the pinion angle θp is used for the calculation of the steering conversion angle θp_s.

-In the first embodiment, the code signal generation unit 66 may detect a mechanical abnormality in the configuration of the steering unit 6 such as the steering side motor 33 through the detection results of various sensors. In this case, the code signal generation unit 66 generates a code signal Sm indicating that the protection mode is executed, for example, when it is determined that the steering side motor 33 has a mechanical abnormality.

-In each of the above embodiments, the pinion angle feedback control unit 63 may execute PID control using a proportional term, an integral term, and a differential term as feedback control of the pinion angle θp. Even in this case, if the deviation axial force Fv is calculated in response to the minute deviation Δθ that appears while the pinion angle θp is made to follow the target pinion angle θp * calculated based on the steering angle θs, the driver The fact that it only interferes with the steering operation is the same as in each of the above embodiments.

In the first embodiment, the deviation axial force calculation unit 73 may delete the gradual change processing unit 103. In this case, the axial force basic component FΔθ calculated by the axial force basic component calculation unit 101 is output to the adder 107 regardless of the mode switching between the normal mode and the protection mode.

In each of the above embodiments, the axial force calculation unit 56 may calculate at least the deviation axial force Fv as the axial force F. In this case, the end axial force calculation unit 72 may be deleted.
In each of the above embodiments, the axial force viscosity component calculation unit 102 may calculate the axial force viscosity component Fω in consideration of parameters other than the steering angular velocity ωs. For example, the axial force viscosity component calculation unit 102 may calculate the axial force viscosity component Fω in consideration of the vehicle speed value V. In this case, for example, the axial force viscosity component calculation unit 102 includes a plurality of maps having different tendencies with respect to the vehicle speed value V, and calculates the axial force viscosity component Fω by referring to the map selected according to the vehicle speed value V. You may do so.

In each of the above embodiments, the axial force viscosity component calculation unit 102 may use the pinion angular velocity, which is the amount of change in the pinion angle θp, instead of the steering angular velocity ωs when calculating the axial force viscosity component Fω. .. In addition, in the calculation of the axial force viscosity component Fω, the target pinion angular velocity, which is the amount of change in the target pinion angle θp *, may be used. Further, in the calculation of the axial force viscosity component Fω, the steering conversion angular velocity, which is the amount of change in the steering conversion angle θp_s, which is the conversion angle, may be used. In this modification, the angular velocities described in the claims correspond to the pinion angular velocities, the target pinion angular velocities, and the steering conversion angular velocities. In addition, when this modification is adopted, the information about the axial force viscosity component Fω may be calculated by the steering side control unit 60, and the information may be transmitted to the steering side control unit 50.

In each of the above embodiments, the axial force viscosity component calculation unit 102 may reflect the axial force viscosity component Fω in the axial force basic component FΔθ when the deviation Δθ is less than the deviation threshold value.
In each of the above embodiments, the deviation axial force calculation unit 73 may delete the axial force viscosity component calculation unit 102. In this case, the deviation axial force calculation unit 73 can delete the adder 107. That is, the post-processing axial force basic component FΔθ'calculated by the gradual change processing unit 103 is output to the upper limit guard processing unit 104.

In the first embodiment, the axial force basic component calculation unit 101 may include one type of map and three or more types of maps as the axial force basic component map. When the axial force basic component calculation unit 101 includes three or more types of maps as the axial force basic component map, for example, a map corresponding to the code "0", the codes "1A", "1B", "2A", "2B" The axial force basic component FΔθ may be calculated using a map corresponding to the state indicated by the code, such as a map corresponding to the map corresponding to the code “1C” and a map corresponding to the codes “1C” and “2C”.

-In the second embodiment, the deviation axial force calculation unit 73 may include three or more deviation axial force component calculation units. In this case, the deviation axial force calculation unit 73 may, for example, have a distribution gain corresponding to the code “0”, a distribution gain corresponding to the codes “1A”, “1B”, “2A”, and “2B”, and codes “1C”, “2B”. A distribution gain corresponding to "2C" may be used to add up three or more deviation axial force components at a predetermined distribution ratio using a distribution gain according to the state indicated by the code.

-In the second embodiment, the sum of the first distribution gain D1 and the second distribution gain D2 may exceed "1 (100%)". This also applies to the case where the deviation axial force calculation unit 73 calculates three or more distribution gains as in the above-mentioned modification, and the sum of the three or more distribution gains is "1 (100%). ) ”May be exceeded.

In the first embodiment, when the axial force basic component calculation unit 101 calculates the axial force basic component FΔθ, the deviation Δθ with the reference angle as the steering angle θs and the conversion angle as the steering conversion angle θp_s is used. Used, but not limited to this. For example, in the calculation of the deviation Δθ, these deviations in which the reference angle is the target pinion angle θp * and the conversion angle is the steering conversion angle θp_s may be used. In addition, in the calculation of the deviation Δθ, the reference angle is converted into the steering angle θs so as to be expressed as the index value of the pinion angle θp according to the rudder angle ratio, and the converted angle is the pinion angle θp. Deviation may be used. Further, in the calculation of the deviation Δθ, these deviations in which the reference angle is the pinion angle θp and the conversion angle is the target pinion angle θp * may be used. In this case, the steering angle conversion unit 65 can be deleted in the steering side control unit 60. This also applies to the second embodiment.

In each of the above embodiments, the deviation axial force calculation unit 73 may be set as a function of the steering side control unit 60. Further, not only the deviation axial force calculation unit 73 but also the axial force calculation unit 56 itself may be set as a function of the steering side control unit 60. In this case, the axial force F calculated by the axial force calculation unit 56 provided in the steering side control unit 60 is output to the target reaction force torque calculation unit 52 of the steering side control unit 50.

In each of the above embodiments, the code signal generation unit 66 may be set as a function of the steering side control unit 50. In this case, the detection results of the temperature sensor, the voltage sensor, etc. detected by the steering side control unit 60 are output to the code signal generation unit provided in the steering side control unit 50.

-In the second embodiment, the distribution ratio calculation unit 113 may calculate the first distribution gain D1 and the second distribution gain D2 based on the code signal Sm. In this case, the subtractor 117 and the storage unit 118 can be deleted. As described above, the deviation axial force component calculation unit may include at least the first deviation axial force component calculation unit 111, the second deviation axial force component calculation unit 112, and the distribution ratio calculation unit 113. Other configurations can be changed as appropriate.

-In the first embodiment, the gradient is different between the axial force basic component maps, for example, the gradient of the axial force basic component FΔθ with respect to the deviation Δθ in the axial force basic component map for the protection mode is increased. May be set to. In this case, the first deviation threshold value Δθ1 and the second deviation threshold value Δθ2 may be set to the same value between the axial force basic component maps, and the dead zone of the deviation Δθ may be set to the same degree. This can be similarly applied to each deviation axial force component map of the second embodiment.

-In the second embodiment, the distribution ratio calculation unit 113 may delete the function of gradually changing the distribution gain D1. In this case, the first distribution gain D1 calculated by the distribution ratio calculation unit 113 is output to the multiplier 114 and the subtractor 117 regardless of the code switching.

-In the first embodiment, it is conceivable that a plurality of situations in which the operation of the steering side motor 33 should be restricted overlap. For example, the situation where the operation of the steering side motor 33 should be restricted from the viewpoint of the heat generation state of the steering side motor 33 and the situation where the operation of the steering side motor 33 should be restricted from the viewpoint of the voltage state of the DC power supply overlap. It is possible that it will occur. In order to deal with this, a priority may be set for the code, for example, the code indicating the heat generation state of the steering side motor 33 is reflected with priority over the code indicating the voltage state of the DC power supply. You may. This also applies to the second embodiment.

-In the first embodiment, the operation of the steering side motor 33 may not be restricted in a slight overheating state or a slight voltage drop state. That is, the allocation of the normal mode and the protection mode for limiting the operation of the steering side motor 33 can be appropriately changed. This also applies to the second embodiment.

-In each of the above embodiments, the angle axial force calculation unit 81 may use at least the target pinion angle θp * when calculating the angle axial force Fr, and may not use the vehicle speed value V, or may use other vehicle speed values V. You may use a combination of elements. The angle axial force calculation unit 81 may use the pinion angle θp instead of the target pinion angle θp *. This is because using the pinion angle θp is the same concept as using the target pinion angle θp *.

In each of the above embodiments, the current axial force calculation unit 82 may use at least the actual current value Ib on the steering side when calculating the current axial force Fi, and may combine other elements such as the vehicle speed value V. You may use it. The current axial force calculation unit 82 uses the current value on the dq coordinate obtained by converting the actual current value Ib on the steering side based on the rotation angle θb on the steering side instead of the actual current value Ib on the steering side. The current command value obtained to eliminate the deviation may be used. This is because using the current command value is the same concept as using the actual current value Ib on the steering side.

-In each of the above embodiments, when the distribution ratio calculation unit 83 calculates the distribution gain Di, instead of or in addition to the vehicle speed value V, the pinion angle θp, the target pinion angle θp *, the steering angle θs, and the pinion Other factors such as the steering speed obtained by differentiating the angle θp may be used.

In each of the above embodiments, the distribution axial force calculation unit 71 may delete the angle axial force calculation unit 81 or the current axial force calculation unit 82. In this case, the distribution ratio calculation unit 83 may be deleted. Then, the angle axis force Fr calculated by the angle axis force calculation unit 81 or the current axis force Fi calculated by the current axis force calculation unit 82 is output to the adder 75.

-In each of the above embodiments, the end axial force calculation unit 72 may use a combination of other elements such as the vehicle speed value V when calculating the end axial force Fie. The end axial force calculation unit 72 may use the pinion angle θp instead of the target pinion angle θp *. This is because using the pinion angle θp is the same concept as using the target pinion angle θp *.

-In each of the above embodiments, the steering force calculation unit 55 may use at least a state variable related to the operation of the steering wheel 3 when calculating the steering force Tb *, and may not use the vehicle speed value V. , Other elements may be used in combination. As the state variable related to the operation of the steering wheel 3, instead of the steering torque Th exemplified in the above embodiment, the steering angle θs may be used or another element may be used.

In each of the above embodiments, the steering side control unit 60 may be added as a function of the steering side control unit 50.
In each of the above embodiments, the steering side motor 33 is, for example, a motor in which the steering side motor 33 is arranged coaxially with the rack shaft 22, or a rack shaft 22 via a belt type speed reducer using a ball screw mechanism. The one connected to may be adopted.

In each of the above embodiments, the steering control device 1 is 1) one or more processors that operate according to a computer program (software), and 2) an integrated circuit (ASIC) for a specific application that executes at least a part of various processes. ) Etc., or a processing circuit including 3) a combination thereof. The processor includes a CPU and a memory such as a RAM and a ROM, and the memory stores a program code or a command configured to cause the CPU to execute a process. Memory or non-temporary computer-readable media includes all available media accessible by general purpose or dedicated computers.

-In each of the above embodiments, the steering device 2 has a linkless structure in which the steering unit 4 and the steering unit 6 are mechanically separated at all times, but the present invention is not limited to this, and the two-dot chain line is shown in FIG. As shown, the structure may be such that the steering portion 4 and the steering portion 6 can be mechanically separated by the clutch 25.

1 ... Steering control device 2 ... Steering device 3 ... Steering wheel 4 ... Steering unit 5 ... Steering wheel 6 ... Steering unit 13 ... Steering side motor 50 ... Steering side control unit 52 ... Target reaction force torque calculation unit 72 ... End axial force Calculation unit 73 ... Deviation axial force calculation unit 74 ... Axial force selection unit 101 ... Axial force basic component calculation unit 102 ... Axial force viscous component calculation unit 111, 112 ... First, second deviation Axial force component calculation unit Fv ... Deviation axis Power

Claims (11)

It has a structure in which the power transmission path between the steering unit connected to the steering wheel and the steering unit that steers the steering wheel by operating the steering shaft according to the steering input to the steering unit is separated. It is a steering control device that controls the steering device.
The steering device has a function of changing the steering angle ratio, which is the ratio of the rotation amount of the steering wheel to the rotation amount of the steering wheel.
A control unit that at least controls the operation of the steering side motor provided in the steering unit so as to generate a steering reaction force that is a force that opposes the steering input to the steering unit is provided.
The control unit has a target reaction force torque calculation unit that calculates a target reaction force torque that is a target value of the motor torque of the steering side motor that is the steering reaction force.
The target reaction force torque calculation unit includes a deviation axial force calculation unit that calculates a deviation axial force for regulating steering for steering the steering wheel in a predetermined direction, which is reflected in the target reaction force torque.
The deviation axial force calculation unit uses an angle of either one of a steering angle set as a value indicating the rotation amount of the steering wheel and a steering angle set as a value indicating the rotation amount of the steering wheel as a reference. The deviation axial force is based on the deviation between the reference angle and the conversion angle, with the angle obtained by converting either one of the steering angle and the steering angle according to the steering angle ratio as the conversion angle. Steering control device configured to calculate. The deviation axial force calculation unit is
A deviation axial force component calculation unit that calculates a deviation axial force component based on the deviation between the reference angle and the conversion angle,
Including an axial force viscosity component calculation unit that calculates an axial force viscosity component based on an angular velocity that is a change amount of the reference angle or the conversion angle in order to adjust a change in the deviation axial force.
The steering control device according to claim 1, wherein the deviation axial force is configured to be obtained by reflecting the axial force viscous component with respect to the deviation axial force component. A turning state quantity set as information indicating the difference between the actual turning behavior of the vehicle and the turning behavior of the ideal vehicle is input to the control unit.
The steering control device according to claim 1 or 2, wherein the deviation axial force calculation unit is configured to calculate the deviation using the steering angle compensated based on the turning state amount. The deviation axial force calculation unit includes a first deviation axial force component obtained based on the deviation and a second deviation axial force component obtained based on the deviation so as to have characteristics different from the first deviation axial force component. Includes a deviation axial force component calculation unit that calculates multiple deviation axial force components including
The deviation axial force component calculation unit with the first deviation axial force component depending on whether the operation of the steering side motor provided in the steering unit is not restricted or the operation is restricted. The steering control device according to any one of claims 1 to 3, wherein any deviation axial force component of the second deviation axial force component is added to the deviation axial force. The deviation axial force component calculation unit switches between a situation in which the operation of the steering side motor is not restricted and a situation in which the operation is restricted, so that the first deviation axial force component and the second deviation axial force component are switched. When switching which of the deviation axial force components should be added to the deviation axial force, it has a function of gradually reducing the difference between the first deviation axial force component and the second deviation axial force component before and after the switching. The steering control device according to claim 4, which is configured in 1. The deviation axial force calculation unit includes a first deviation axial force component obtained based on the deviation and a second deviation axial force component obtained based on the deviation so as to have characteristics different from the first deviation axial force component. Includes a deviation axial force component calculation unit that sums up multiple deviation axial force components including
The deviation axial force component calculation unit changes the distribution ratio according to whether the operation of the steering side motor provided in the steering unit is not restricted or the operation is restricted. The steering control device according to any one of claims 1 to 3, wherein the deviation axial force component added up by the distribution ratio is added to the deviation axial force. When the deviation axial force component calculation unit changes the distribution ratio due to switching between a situation in which the operation of the steering side motor is not restricted and a situation in which the operation is restricted, the distribution ratio is changed. The steering control device according to claim 6, which is configured to have a function of gradually changing the speed. When the absolute value of the deviation is equal to or greater than the deviation threshold value, the deviation axial force component calculation unit determines the gradient of the deviation axial force component with respect to the deviation as compared with the case where the absolute value of the deviation is less than the deviation threshold value. It is configured to be set large and
The deviation axial force component calculation unit is configured to set the absolute value of the deviation threshold smaller in a situation where the operation of the steering side motor is restricted than in a situation where the operation of the steering side motor is not restricted. The steering control device according to any one of claims 4 to 7. The target reaction force torque calculation unit includes an end axial force calculation unit that calculates an end axial force for restricting steering in a direction exceeding the steering angle limit.
The steering control device according to any one of claims 1 to 8, wherein the target reaction force torque calculation unit is configured to have a function of individually calculating the deviation axial force and the end axial force. The target reaction force torque calculation unit has an axial force selection unit that selects the axial force having the largest absolute value among a plurality of axial forces including the deviation axial force and the end axial force.
The steering control device according to claim 9, wherein the target reaction force torque calculation unit is configured to obtain the target reaction force torque by reflecting the axial force selected by the axial force selection unit. The control unit is a steering side control unit that executes reaction force control for generating the steering reaction force through the drive control of the steering side motor, and the steering unit is rotated through the drive control of the steering side motor provided in the steering unit. It is equipped with a steering side control unit that executes steering control to steer the steering wheel.
The steering side control unit has a steering angle ratio variable control unit that controls to change the steering angle ratio based on a vehicle speed value set as information indicating the traveling speed of the vehicle, and the steering angle. Includes a steering angle conversion unit that calculates the steering conversion angle converted to the steering angle according to the steering angle ratio.
The reference angle is the steering angle.
The steering control device according to any one of claims 1 to 10, wherein the conversion angle is the steering conversion angle.

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