JP3551426B2 - Steering control device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a steering control device in which a steering mechanism and a turning mechanism are mechanically separated from each other, and an electrical control device replaces the connecting mechanism.
[0002]
[Prior art]
An example of a steering control device that electrically controls the operations of the steering mechanism and the turning mechanism in this way is disclosed in, for example, Japanese Patent Application Laid-Open No. 1-233170. This steering control device detects a steering position of a steering wheel by an encoder provided on a steering shaft, and detects a traveling direction of the vehicle by a yaw rate gyro. Then, the steered wheels are steered so that the deviation between the travel change instruction value based on the detected steering position and the actual travel direction change amount based on the yaw rate gyro detection result becomes zero.
[0003]
[Problems to be solved by the invention]
As described above, since the turning control of the steered wheels is performed based on the steering wheel operation, for example, from turning off the ignition key to stopping the engine, turning on the ignition key again to start the engine. In the meantime, if the steering wheel is operated to another steering position, the state of the positional relationship between the steering position of the steering wheel and the steering position of the steered wheels does not match when the engine is started. In such a case, how to perform the steering control is not disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 1-233170.
[0004]
The present invention has been made in order to solve such a problem, and an object of the present invention is to determine the driver's will when the steering position of the steering wheel does not match the steering position of the steered wheels when the engine is started. An object of the present invention is to provide a steering control device that can appropriately perform steering control.
[0005]
[Means for Solving the Problems]
Therefore, a steering control device according to a first aspect of the present invention is a steering control device for turning a steered wheel in conjunction with a steering wheel, a steering position detecting means for detecting a steering position of the steering wheel, and a steering wheel connected to the steering wheel. A steering shaft driving unit that drives the shaft, a load state detecting unit that detects a load state of the steering shaft driving unit, a steering shaft that is mechanically separated from the steering shaft and that is connected to a steered wheel, and a steering shaft. Turning shaft driving means for driving, turning position detecting means for detecting a turning position of a turning wheel, and first control means for driving the steering shaft driving means in a steering position direction corresponding to the turning position when the engine is started. And second control means for controlling the driving of the steering shaft driving means and the steered shaft driving means according to the load state of the steering shaft driving means driven by the first control means.
[0006]
When the engine is started, the first control means drives the steering shaft drive means to apply a rotational force to the steering wheel. At this time, if the driver holds the steering wheel against this torque or operates the steering wheel in the direction opposite to the direction of the torque, the load state of the steering shaft driving means becomes large. Further, when the driver releases his / her hand from the steering wheel or operates the steering wheel in the forward direction along the direction of the rotational force, the load state of the steering shaft driving means becomes small. The second control means controls the driving of the steering shaft driving means and the steered shaft driving means according to the magnitude of the load state.
[0007]
According to a second aspect of the present invention, there is provided a steering control device, wherein the second control means determines whether the load state of the steering shaft driving means is large or small. A third control unit that performs drive control of the shaft driving unit and turns the steered wheels to a steering position corresponding to the steering position; and a driving control of the steering shaft driving unit when the load state of the steering shaft driving unit is small. And a fourth control means for rotating the steering wheel to a steering position corresponding to the steered position.
[0008]
If the load state determined by the determination means is large, it is determined that the driver has a will to turn the steered wheels, and the third control means having received the determination result performs steering hold. The drive control of the steered shaft driving means is performed so that the steered wheels are steered to a position corresponding to the steering position of the steered steering wheel. If the load state determined by the determination means is small, it is determined that there is a driver's will to permit the rotation of the steering wheel up to the steering position corresponding to the steered position of the steered wheels. The fourth control unit that receives the result performs drive control of the steering shaft driving unit so that the steering wheel rotates to the steering position corresponding to the steering position of the steered wheel at that time.
[0009]
According to a third aspect of the present invention, there is provided the steering control device according to the first or second aspect, wherein the load state detection unit detects a driving current of the steering shaft driving unit and a torque sensor that detects a steering torque applied to the steering wheel. It consists of either.
[0010]
The magnitude of the load on the steering shaft driving means corresponds to the magnitude of the driving current of the steering shaft driving means or the magnitude of the steering torque applied to the steering shaft. Therefore, by detecting the current value or the magnitude of the steering torque with the current sensor or the torque sensor, it is possible to detect the load state of the steering shaft driving means.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0012]
FIG. 1 schematically shows a configuration of a steering control device according to the present embodiment. This steering control device includes a master unit 10 operated by a driver, a slave unit 20 for turning a steered wheel 21, and a controller 30 for electrically controlling the master unit 10 and the slave unit 20.
[0013]
The master unit 10 includes a steering shaft 12 to which a steering handle 11 is attached, and a steering shaft motor 13 for driving the steering shaft 12 to rotate. The steering shaft 12 has a steering angle for detecting a steering position of the steering handle 11. The vehicle includes a sensor 14 and a torque sensor 15 that detects a steering torque applied to the steering wheel 11. Further, the steering shaft motor 13 is provided with a current sensor 16 for detecting a drive current flowing through the steering shaft motor 13.
[0014]
The slave unit 20 includes a steered shaft motor 23 serving as a drive source when the steered shaft 22 is displaced and driven, and a steered shaft motor 23 is provided between the steered shaft motor 23 and the steered shaft 22. A converter 24 is provided for converting the rotational movement of the steering wheel 23 into a linear movement and displacing the steered shaft 22 along the axial direction. On both sides of the steered shaft 22, reaction force sensors 26 for detecting an axial force (steering reaction force) applied from the steered wheels 21 to the steered shaft 22 are provided. The steering shaft 22 is provided with a stroke sensor 25 for detecting the displacement position of the steering shaft 22. Since the displacement position of the steering shaft 22 corresponds to the steering position of the steered wheels 21, By detecting the displacement position of the rudder shaft 22 with the stroke sensor 25, the steered position of the steered wheels 21 is detected.
[0015]
The controller 30 is provided with the detection results of the steering angle sensor 14, the torque sensor 15, the current sensor 16, the stroke sensor 25, and the reaction force sensor 26, and based on these detection results, controls the steering shaft motor 13 and the turning shaft motor 23. Drive control is being performed.
[0016]
Hereinafter, each control process performed by the controller 30 will be described.
[0017]
The control of the reaction force applied to the steering wheel 11 is performed as follows. Based on the deviation between the steering torque T detected by the torque sensor 15 and the steering reaction force F detected by the reaction force sensor 26, the duty value V1 of the drive voltage applied to the steering shaft motor 13 is calculated by the following equation (1). And outputs a control signal corresponding to the calculated Duty value to the steering shaft motor 13. In the equation (1), K1 is a gain coefficient indicating the gain of the control signal.
V1 = K1 · (T−F) (1)
[0018]
The steering position control of the steered wheels 21 is performed as follows. Based on the actual steering position θr detected by the steering angle sensor 14, a target steering position Xm that is the steering position of the steered wheels 21 corresponding to the actual steering position θr is calculated. Then, based on the deviation between the actual turning position Xr detected by the stroke sensor 25 and the calculated target turning position Xm, the duty value V2 of the drive voltage applied to the turning shaft motor 23 is calculated by the following equation (2). And outputs a control signal corresponding to the calculated Duty value to the steered shaft motor 23. In the equation (2), K2 is a gain coefficient indicating the gain of the control signal.
V2 = K2 · (Xm−Xr) (2)
[0019]
When the phase relationship between the actual steering position θr of the steering wheel 11 and the actual steering position Xr of the steered wheels 21 does not match when the engine is started, the controller 30 performs phase adjustment control for adjusting the positional relationship between the two. .
[0020]
FIG. 2 shows a flowchart for determining the phase relationship between the actual steering position θr of the steering wheel 11 and the actual steering position Xr of the steered wheels 21. First, in step 101 (hereinafter, step is referred to as “S”), it is determined whether or not an ignition switch is turned on. When the ignition switch is turned on (“Yes” in S101), the process proceeds to S103, in which the actual steering position θr as the detection result of the steering angle sensor 14 and the actual steering position Xr as the detection result of the stroke sensor 25 are set. Is read.
[0021]
Next, in S105, a target turning position Xm as a turning position of the turning wheel 21 corresponding to the actual steering position θr is calculated from the read actual steering position θr. In subsequent S107, it is determined whether or not the target turning position Xm calculated in S105 matches the actual turning position Xr read in S103. When it is determined in S107 that the target turning position Xm matches the actual turning position Xr, the phases of the actual steering position θr of the steering wheel 11 and the actual turning position Xr of the steered wheels 21 match. Therefore, the phase adjustment is unnecessary, and this control flow ends.
[0022]
On the other hand, if it is determined in S107 that the target turning position Xm does not match the actual turning position Xr, the phase relationship between the actual steering position θr of the steering wheel 11 and the actual turning position Xr of the steered wheels 21 is one. I will not do it. In this case, the process proceeds to S200, and the phase adjustment control for matching the phase relationship between the actual steering position θr of the steering wheel 11 and the actual steering position Xr of the steered wheels 21 is performed.
[0023]
FIG. 3 shows a flowchart of the phase adjustment control performed in S200.
[0024]
First, in S201, a target steering position θm of the steering wheel 11 corresponding to the actual steering position Xr is calculated from the actual steering position Xr at that time based on the detection result of the stroke sensor 25.
[0025]
Next, in S203, based on the target steering position θm calculated in S201 and the actual steering position θr detected by the steering angle sensor 14, the actual steering position θr of the steering wheel 11 is moved toward the target steering position θm. Then, the steering shaft motor 13 is rotationally driven. At this time, the Duty value of the drive voltage applied to the steering shaft motor 13 is predetermined, whereby the turning force is applied to the steering wheel 11 by the predetermined output torque, and the direction of the turning force is This is the direction in which the steering wheel 11 moves toward the target steering position θm.
[0026]
In S205, the current value I of the drive current of the steering shaft motor 13, which is the detection result of the current sensor 16, is read, and the load state of the steering shaft motor 13 at this time is detected. In the following S207, the current value I read at this time is compared with a preset threshold value Is. If the current value I is smaller than the threshold value Is ("Yes" in S207), the steering shaft is adjusted. The load state of the motor 13 is small. In this case, it is assumed that the driver releases his / her hand from the steering wheel 11 or operates the steering wheel in the direction of the rotational force applied to the steering wheel 11. In such a case, it is determined that there is a driver's intention to permit the rotation of the steering wheel 11 to a position corresponding to the steered position of the steered wheels 21, and the steering shaft motor 13 driven in S203 is continued. Drive.
[0027]
In subsequent S209, it is determined whether or not the actual steering position θr of the rotationally driven steering wheel 11 matches the target steering position θm calculated in S201. When it is determined that the actual steering position θr of the steering wheel 11 does not coincide with the target steering position θm (“No” in S209), the processing from S205 is repeated again. If it is determined in S209 that the actual steering position θr of the steering wheel 11 matches the target steering position θm (“Yes” in S209), the actual steering position θr of the steering wheel 11 and the actual rotation of the steered wheels 21 are performed. Since the phase with the rudder position Xr matches, the phase adjustment control ends.
[0028]
On the other hand, in S207, when the read current value I is equal to or greater than the threshold Is ("No" in S207), the load state of the steering shaft motor 13 is large. It is assumed that the steering wheel 11 is held against the turning force applied to the steering wheel 11, or the steering wheel is operated in a direction opposite to the turning force. In such a case, it is determined that there is a driver's intention to turn the steered wheels 21, and the actual turning position Xr of the steered shaft 22 is calculated by the target turning calculated in S105 in FIG. The steering shaft motor 23 is driven to move to the rudder position Xm. In this case as well, the steering shaft motor 13 driven in S203 is continuously driven.
[0029]
In subsequent S213, it is determined whether or not the actual turning position Xr of the displacement-driven turning shaft 22 matches the target turning position Xm. If it is determined that the actual turning position Xr of the turning shaft 22 does not match the target turning position Xm ("No" in S213), the processing from S205 onward is repeated again. Then, if it is determined in S213 that the actual turning position Xr of the turning shaft 22 matches the target turning position Xm ("Yes" in S213), the actual turning position θr of the steering wheel 11 and the steered wheels are determined. Since the phase of the actual steering position Xr matches the phase of the actual steering position Xr, the phase adjustment control ends.
[0030]
As described above, even when a phase shift occurs between the actual steering position θr of the steering wheel 11 and the actual steering position Xr of the steered wheels 21 at the time of starting the engine, the controller 30 performs such control processing. By doing so, it is possible to perform the phase adjustment control according to the driver's will.
[0031]
In the flowchart of the phase determination in FIG. 2 among the embodiments described above, whether or not to shift to the phase adjustment control in S200 by comparing the calculated target turning position Xm with the actual turning position Xr of the turning wheel 21 is determined. For example, in step S105, the target steering position θm corresponding to the actual steering position Xr is calculated based on the read actual steering position Xr, and in step S107, the calculated target steering position θm is calculated based on the actual steering position θm. It is also possible to configure the flow of the phase determination so that when the position does not coincide with the position θr, the process shifts to the phase adjustment control in S200.
[0032]
Further, the case where the current sensor 16 is provided in order to determine the load state of the steering shaft motor 13 has been described as an example. However, the present invention is not limited to this example. The load state can also be determined. In this case, for example, in S207, the detected steering torque is compared with a predetermined threshold, and if the detected steering torque is smaller than the threshold, the load state of the steering shaft motor 13 is small. , The load state of the steering shaft motor 13 is determined to be large. Then, similarly, drive control of the steering shaft motor 13 and the steered shaft motor 23 may be performed.
[0033]
【The invention's effect】
As described above, according to the steering control apparatus according to the claims, the first control means drives the steering shaft driving means in the steering position direction corresponding to the steering position at the time of starting the engine. From the load state of the shaft driving means, the driver's will to steer the steered wheels to a position corresponding to the steering position of the steering wheel, or to rotate the steering wheel to a position corresponding to the steered position of the steered wheel, You can judge. Further, the second control means controls the driving of the steering shaft driving means and the turning shaft driving means in accordance with the load state of the steering shaft driving means at this time, so that the steering position and the turning position in accordance with the driver's will are controlled. It becomes possible to execute the phase adjustment control with the rudder position.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of a steering control device according to an embodiment.
FIG. 2 is a flowchart for determining a phase relationship between an actual steering position of a steering wheel and an actual steering position of a steered wheel.
FIG. 3 is a flowchart illustrating phase adjustment control between a steering position and a steered position.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Master part, 11 ... Steering handle, 12 ... Steering axis, 13 ... Steering axis motor, 14 ... Steering angle sensor, 15 ... Torque sensor, 16 ... Current sensor, 20 ... Slave part, 21 ... Steered wheel, 22 ... Rolling Rudder shaft, 23: steering shaft motor, 25: stroke sensor.

Claims (3)

In a steering control device that turns a steered wheel in conjunction with a steering wheel,
Steering position detection means for detecting a steering position of the steering wheel;
Steering shaft driving means for driving a steering shaft connected to the steering handle;
Load state detection means for detecting a load state of the steering shaft drive means,
A steered shaft mechanically separated from the steered shaft and connected to the steered wheels;
Turning shaft driving means for driving the turning shaft;
Turning position detecting means for detecting a turning position of the steered wheels,
First control means for driving the steering shaft drive means in a steering position direction corresponding to a steering position when the engine is started;
A steering control device comprising: a second control unit that controls driving of the steering shaft driving unit and the steering shaft driving unit in accordance with a load state of the steering shaft driving unit that is driven by the first control unit. The second control means includes:
Determining means for determining the magnitude of the load state of the steering shaft driving means;
When the load state of the steering shaft driving unit is large, a third control unit that performs drive control of the steering shaft driving unit, and turns the steered wheels to a steering position corresponding to a steering position;
4. A fourth control means for controlling the driving of the steering shaft driving means when the load state of the steering shaft driving means is small, and rotating the steering handle to a steering position corresponding to a steered position. Steering control device. The steering according to claim 1, wherein the load state detection unit is one of a current sensor that detects a drive current of the steering shaft driving unit, and a torque sensor that detects a steering torque applied to the steering wheel. Control device.

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