JP3897971B2 - Vehicle steering system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle steering apparatus configured to steer a steering wheel based on an operation of an operation member such as a steering wheel.
[0002]
[Prior art]
Eliminates the mechanical coupling between the steering wheel and the steering mechanism for steering the steering wheel, detects the steering wheel operation direction and the operation amount, and based on the detection result, the steering mechanism has an electric motor, etc. There has been proposed a vehicle steering device (so-called steer-by-wire system) in which a driving force from a steering actuator is applied.
[0003]
By adopting such a configuration, it is possible to prevent the steering wheel from being pushed up at the time of a vehicle collision. Moreover, the degree of freedom of the arrangement position of the steering wheel is increased, and further, it is possible to adopt other operation members such as a lever or a pedal other than the steering wheel.
[0004]
[Problems to be solved by the invention]
However, the steer-by-wire system as described above has a problem that it is expensive due to the large number of components of the system.
SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle steering apparatus in which the cost is reduced by simplifying the configuration.
[0005]
[Means for Solving the Problems and Effects of the Invention]
In order to achieve the above object, an invention according to claim 1 includes an operation member (30) for steering a vehicle, a steering mechanism (10) for turning a steering wheel of the vehicle, and the steering mechanism. The steering actuator (50) for generating a driving force to be applied to the operating member, the reaction force actuator (40) for generating an operating reaction force to be applied to the operating member, and the steering actuator and the reaction force actuator are connected in parallel to each other and are identical. And a common driver (80) for supplying the driving voltage in parallel to the steering actuator and the reaction force actuator .
[0006]
According to a second aspect of the present invention, there is provided a target rudder angle setting means (71) for setting a target rudder angle of the steering wheel according to the operation of the operation member, and a target rudder angle setting for setting the rudder angle of the steering wheel. A voltage command value setting means (73) for setting a voltage command value to be supplied to the steering actuator in order to match the target steering angle set by the means, and a voltage command value set by the voltage command value setting means. The vehicle steering apparatus according to claim 1, further comprising: a driver control means (70) for controlling the shared driver.
[0007]
In addition, the alphanumeric characters in parentheses represent corresponding components in the embodiments described later. Hereinafter, this is the same in this section.
According to the above invention, the driver for the steering actuator and the reaction force actuator are shared, so that the configuration is simplified compared to the conventional device in which the driver for the steering actuator and the driver for the reaction force actuator are provided separately. Yes. Thereby, reduction of apparatus cost can be achieved.
[0008]
Further, since the driver is shared, it is not necessary to prepare the control logic for the steering actuator and the reaction force actuator separately, and only one driver control means or the like as in claim 2 is required. This configuration can also be simplified.
According to a third aspect of the present invention, a power source (81) connected to the shared driver, a relay (83) interposed between the power source and the shared driver, and the power source are supplied to the shared driver. Current detection means (84) for detecting current, and relay control means (70, S2) for disconnecting the relay when the current value detected by the current detection means is a predetermined abnormal value. The vehicle steering apparatus according to claim 1 or 2, characterized in that.
[0009]
According to a fourth aspect of the present invention, there is provided a clutch mechanism (20) capable of mechanically connecting / disconnecting the operation member and the steering mechanism, and a current value detected by the current detection means is a predetermined abnormal value. 4. The vehicle steering apparatus according to claim 3, further comprising clutch control means (70, S3) for bringing the clutch mechanism into a connected state in some cases.
According to these inventions, the current supplied from the power source to the shared driver is constantly monitored. If the current supplied to the common driver becomes an abnormal value, that is, a value that can be taken when an abnormality occurs in the steering actuator, reaction force actuator, or common driver, the relay is disconnected and the steering actuator And the supply of the drive voltage to the reaction force actuator is stopped. As a result, when an abnormality occurs in the steering actuator, the reaction force actuator, or the common driver, the drive voltage supply to the steering actuator and the reaction force actuator is individually stopped. The logic of this can be simplified, and as a result, a further reduction in device cost can be achieved.
[0010]
In particular, in the case of the configuration of the fourth aspect, the vehicle can be steered satisfactorily even when a failure occurs in the steering drive system by setting the clutch mechanism in the connected state.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an illustrative view showing a configuration of a vehicle steering apparatus according to an embodiment of the present invention. This vehicle steering apparatus is mechanically connected to a steering mechanism 10 for causing a pair of steering wheels (normally front wheels) W, W to perform a steering operation, and to the steering mechanism 10 via a clutch 20. / A steering wheel 30 that can be separated and a reaction force actuator 40 that applies an operation reaction force to the steering wheel 30.
[0012]
The steering mechanism 10 includes a steering shaft 11 that extends in the left-right direction of the vehicle body, and knuckle arms 13 and 13 that are coupled to both ends of the steering shaft 11 via tie rods 12 and 12 and support wheels W and W. And have. The steering shaft 11 is supported by the housing 14 and is slidable in the axial direction. A steering actuator 50 is coaxially incorporated in the middle of the steering shaft 11. The steering actuator 50 is composed of, for example, a brushed DC motor. When the steering actuator 50 is driven, the rotation of the steering actuator 50 is converted into sliding of the steering shaft 11 by a motion conversion mechanism including a ball screw and the steering of the wheels W and W is achieved by the sliding of the steering shaft 11. Is done.
[0013]
A rack gear 11a is formed on a part of the steering shaft 11, and a pinion gear 22 at the tip of a shaft 21 coupled to one side of the clutch 20 is engaged with the rack gear 11a. A shaft 23 coupled to the other side of the clutch 20 is coupled to the steering wheel 30. Therefore, if the clutch 20 is in the connected state, the steering torque applied to the steering wheel 30 is mechanically transmitted to the steering shaft 11 via the clutch 20, thereby achieving the steering of the wheels W and W. The
[0014]
The reaction force actuator 40 is constituted by a brushed DC motor having a shaft 23 that couples the clutch 20 and the steering wheel 30 as a rotating shaft, and a casing thereof is fixed at a proper position of the vehicle body. A steering angle sensor 61 for detecting the steering angle δh of the steering wheel 30 is provided in association with the shaft 23 between the reaction force actuator 40 and the steering wheel 30. A detection signal from the steering angle sensor 61 is supplied to a controller 70 including a microprocessor.
[0015]
Further, a pinion angle sensor 62 for detecting the rotation angle (steering angle) δ of the pinion gear 22 is provided in association with the shaft 21 between the clutch 20 and the pinion gear 22, and the detection of the pinion angle sensor 62 is provided. A signal is also input to the controller 70. Further, a detection signal of a vehicle speed sensor 63 for detecting the vehicle speed SV is input to the controller 70.
The controller 70 sets a voltage command value V ^* based on the input signals from the sensors, and gives a control signal corresponding to the set voltage command value V ^* to the motor driver 80. In this embodiment, a steering actuator 50 and a reaction force actuator 40 are connected to the motor driver 80 in parallel. Thus, when the voltage command value V ^* is given from the controller 70 to the motor driver 80, a voltage corresponding to the given voltage command value V ^* is applied to the steering actuator 50 and the reaction force actuator 40 in parallel. As a result, torque for sliding the steering shaft 11 in the direction corresponding to the operation direction of the steering wheel 30 is output from the steering actuator 50, and reaction force corresponding to the operation of the steering wheel 30 is output from the reaction force actuator 40. Is output.
[0016]
For example, when a large steering torque is suddenly applied to the steering wheel 30, it is necessary to apply a large torque to the steering mechanism 10 and to apply a large operational reaction force to the steering wheel 30. On the contrary, when a small steering torque is slowly applied to the steering wheel 30, the torque applied to the steering mechanism 10 and the operation reaction force applied to the steering wheel 30 may be small. That is, when it is necessary to apply a large torque from the steering actuator 50 to the steering mechanism 10, it is necessary to apply a large operating reaction force from the reaction force actuator 40 to the steering wheel 30, and the torque applied from the steering actuator 50 to the steering mechanism 10 is small. When it is possible, the operation reaction force applied from the reaction force actuator 40 to the steering wheel 30 may be small. Therefore, even if the drivers of the steering actuator 50 and the reaction force actuator 40 are shared, the steering actuator 50 and the reaction force actuator 40 can be driven and controlled satisfactorily.
[0017]
In this embodiment, the power supply circuit 82 for supplying the voltage of the battery (power supply) 81 to the motor driver 80 is switched to the relay 83 for switching the supply and stop of the power supply voltage to the motor driver 80. A current sensor 84 for detecting a driver current supplied to 80 is interposed. The detection signal of the current sensor 84 is input to the controller 70. The controller 70 monitors the driver current detected by the current sensor 84, and controls the clutch 20 and the relay 83 based on the monitoring result.
[0018]
FIG. 2 is a block diagram showing a configuration for setting the voltage command value V ^* based on the steering angle δh, the steering angle δ, and the vehicle speed SV. The steering angle δh detected by the steering angle sensor 61 and the vehicle speed SV detected by the vehicle speed sensor 63 are input to a target steering angle setting unit 71 realized by a program process by a microcomputer provided in the controller 70. The The target rudder angle setting unit 71 has a table prepared for each predetermined vehicle speed range, and the target rudder angle setting unit 71 refers to a table corresponding to the vehicle speed SV detected by the vehicle speed sensor 63. A target steering angle δ ^* corresponding to the steering angle δh detected by the steering angle sensor 61 is set.
[0019]
The target rudder angle δ ^* set by the target rudder angle setting unit 71 is given to the subtracting unit 72. The subtraction unit 72 is also provided with a steering angle δ that is a rotation angle of the pinion gear 22 detected by the pinion angle sensor 62. Subtraction unit 72, a deviation [delta] ^* - [delta between the target steering angle [delta] ^* and the steering angle [delta], giving the obtained deviation [delta] ^* - [delta voltage command value setting unit 73. Voltage command value setting unit 73 sets voltage command value V ^* according to a predetermined steering angle feedback control law based on deviation δ ^* −δ given from subtraction unit 72.
[0020]
The subtracting unit 72 and the voltage command value setting unit 73 are also realized by a program process by a microcomputer provided in the controller 70.
FIG. 3 is a flowchart for explaining fail-safe processing executed by the controller 70. As described above, the controller 70 constantly monitors the driver current detected by the current sensor 84, and repeatedly determines whether the driver current is not an abnormal value (step S1).
[0021]
For example, when the voltage command value V ^* is set to a relatively large value, the driver current detected by the current sensor 84 is relatively small, or the voltage command value V ^* is set to a relatively small value. However, if the driver current detected by the current sensor 84 is relatively large, it is considered that an abnormality has occurred in any of the reaction force actuator 40, the steering actuator 50, or the motor driver 80. . Therefore, if the value of the driver current with respect to the voltage command value V ^* is abnormal, the controller 70 determines that an abnormality has occurred in any of the reaction force actuator 40, the steering actuator 50, or the motor driver 80. Then, the relay 83 interposed in the power supply circuit 82 is disconnected, and the supply of the driver current from the battery 81 to the motor driver 80 is stopped (step S2). Further, the clutch 20 is brought into a connected state (step S3). As a result, the steering torque applied to the steering wheel 30 is mechanically transmitted to the steering shaft 11, and the wheels W, W are steered in accordance with the operation of the steering wheel 30.
[0022]
As described above, according to this embodiment, the motor driver 80 is shared as the driver of the reaction force actuator 40 and the steering actuator 50, whereby the driver of the reaction force actuator 40 and the driver of the steering actuator 50 are provided separately. The configuration is simplified compared to the above apparatus. Thereby, reduction of apparatus cost can be achieved.
Furthermore, since the motor driver 80 is shared, it is not necessary to separately prepare the control logic of the reaction force actuator 40 and the steering actuator 50, so that the configuration for actuator control can be simplified.
[0023]
In this embodiment, the driver current supplied from the battery 81 to the motor driver 80 is constantly monitored. If the driver current becomes an abnormal value, it is determined that an abnormality has occurred in the reaction force actuator 40, the steering actuator 50, or the motor driver 80, and the drive voltage is supplied to the reaction force actuator 40 and the steering actuator 50. While being stopped, the clutch 20 is brought into a connected state. Thereby, the fail safe of the steering drive system can be realized, and the vehicle can be steered well even when a failure occurs.
[0024]
In addition, the supply of drive voltage to the reaction force actuator 40 and the steering actuator 50 is stopped by disconnecting a relay 83 interposed between the motor driver 80 and the battery 81. As a result, the logic for fail-safe can be simplified as compared with the conventional device that individually controls the supply / stop of the drive voltage to the reaction force actuator 40 and the steering actuator 50, and as a result, Further reductions in device costs can be achieved.
[0025]
As mentioned above, although one Embodiment of this invention was described, this invention can also be implemented with another form. For example, although the example in which the steering wheel 30 is used as the operation member has been described, other operation members such as a lever may be used.
In addition, various design changes can be made within the scope of matters described in the claims.
[Brief description of the drawings]
FIG. 1 is an illustrative view showing a configuration of a vehicle steering apparatus according to an embodiment of the present invention;
FIG. 2 is a block diagram showing a configuration for setting a voltage command value.
FIG. 3 is a flowchart for explaining fail-safe processing.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Steering mechanism 20 Clutch 30 Steering wheel 40 Reaction force actuator 50 Steering actuator 61 Steering angle sensor 62 Pinion angle sensor 63 Vehicle speed sensor 70 Controller 71 Target steering angle setting part 72 Subtraction part 73 Voltage command value setting part 80 Motor driver 81 Battery 82 Power supply Circuit 83 Relay 84 Current sensor W Wheel V ^* Voltage command value δ Steering angle δ ^* Target steering angle

Claims (4)

An operating member for steering the vehicle;
A steering mechanism for steering the steering wheel of the vehicle;
A steering actuator that generates a driving force to be applied to the steering mechanism;
A reaction force actuator that generates an operation reaction force to be applied to the operation member;
A steering apparatus for a vehicle, comprising: the steering actuator and the reaction force actuator connected in parallel to each other, and a common driver for supplying the same drive voltage to the steering actuator and the reaction force actuator in parallel . Target rudder angle setting means for setting a target rudder angle of the steering wheel according to the operation of the operation member;
Voltage command value setting means for setting a voltage command value to be supplied to the steering actuator in order to match the steering angle of the steering wheel with the target steering angle set by the target steering angle setting means;
2. The vehicle steering apparatus according to claim 1, further comprising driver control means for controlling the shared driver based on the voltage command value set by the voltage command value setting means. A power supply connected to the shared driver;
A relay interposed between the power source and the shared driver;
Current detection means for detecting a current supplied from the power source to the shared driver;
3. The vehicle steering apparatus according to claim 1, further comprising relay control means for disconnecting the relay when the current value detected by the current detection means is a predetermined abnormal value. A clutch mechanism capable of mechanically connecting / disconnecting the operation member and the steering mechanism;
4. The vehicle steering apparatus according to claim 3, further comprising clutch control means for bringing the clutch mechanism into a connected state when the current value detected by the current detection means is a predetermined abnormal value.

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