JP2004182008A - Steering control system of vehicle and steering system control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering control device of a vehicle capable of making itself as a reaction force generating means not required to be furnished with an actuator of large capacity by alarming at the time when deviation between manipulated variable of a steering means and an actual angle of a steered wheel becomes excessive and capable of making a steering control system small, light in weight and low in cost and a steering system control method of the vehicle. <P>SOLUTION: This steering control device is furnished with a CPU (central processing unit) of a steered wheel control circuit 30 to detect a steered wheel angle abnormality unable to control a tire T in a direction in accordance with a rotating angle of a steering wheel 10, a reaction force motor driving control part 200 to generate an alarm to a driver at the time of detecting abnormality by the CPU of the steered wheel control circuit 30 and a reaction force motor 12. The alarm to the driver is made by microscopically vibrating the steering wheel 10, etc. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a steering control system for a vehicle that controls the direction of a steered wheel according to an operation amount of a steering device operated by a driver of the vehicle, and particularly issues a warning when an abnormality occurs in control of the direction of a steered wheel. The present invention relates to a vehicle steering control device and a vehicle steering system control method.
[0002]
[Prior art]
Patent Document 1 discloses a steer-by-wire system that eliminates mechanical connection between a steering wheel of a vehicle and a mechanism for changing the direction of a steered wheel, and controls the direction of a steered wheel according to the rotation angle of the steering wheel. is there. This document discloses that a reaction force generating means for applying a reaction force in a direction opposite to a direction in which a steering wheel is operated is provided, and the strength of the reaction force is controlled according to a vehicle speed or a road surface condition.
[0003]
[Patent Document 1]
JP-A-9-142330
[0004]
[Problems to be solved by the invention]
In such a steer-by-wire system, the angle of the steering wheel and the actual direction of the steering wheel may not match when the steering wheel is fitted into a groove or hits a curb. That is, in the conventional steering device, the steering wheel and the link mechanism for changing the direction of the steering wheel are mechanically connected, and the angle of the steering wheel always matches the actual direction of the steering wheel. However, in the steer-by-wire system, the angle of the steering wheel is only one piece of input information. Therefore, if the direction (steering angle) of the steering wheel corresponding to the angle of the steering wheel cannot be obtained, the target angle of the steering wheel and the actual steering angle A deviation occurs between the angle and the actual angle. When the vehicle is started in such a state, the vehicle travels in a direction slightly different from the direction intended by the driver.
[0005]
For this reason, when the deviation between the target angle and the actual angle of the steered wheels becomes excessive, the reaction force generation means returns the steering wheel to a position corresponding to the actual angle of the steered wheels, so that the reaction force corresponding to the deviation is returned. It is conceivable to give power. However, when the steering wheel is operated beyond the reaction force that can be generated by the reaction force generating means, the position of the steering wheel cannot be returned by the reaction force generating means. In addition, even when the driver operates the steering wheel with a large force, a large-capacity actuator is required to generate a reaction torque that can return the steering wheel to a position corresponding to the actual angle of the steered wheel. The size of the generating means increases, the weight increases, and the cost increases.
[0006]
The present invention can be a reaction force generating means that does not need to have a large-capacity actuator by issuing a warning when a deviation between the operation amount of the steering means and the actual angle of the steered wheels becomes excessive. It is another object of the present invention to provide a vehicle steering control device and a vehicle steering system control method that can reduce the size, weight, and cost of a steering control system.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 is an operation amount detection unit that detects an operation amount of a steering unit, a steering wheel driving unit that drives a steering wheel to change its direction, and the steering wheel according to an operation amount of the steering unit. A steering control system for a vehicle, comprising: a steering wheel control unit that gives an instruction to a driving unit to control the direction of a steering wheel.In the vehicle steering control system, based on a monitoring result of a control target state quantity to be controlled by the steering wheel control unit, A steering wheel angle abnormality detecting unit that detects a steering wheel angle abnormality that cannot control a steered wheel in a direction corresponding to the operation amount of the steering unit; and an alarm when a steering wheel angle abnormality is detected by the steering wheel angle abnormality detecting unit. Alarm means for issuing an alarm.
[0008]
According to a second aspect of the present invention, there is provided the steering control system for a vehicle according to the first aspect, further comprising a steering wheel angle detecting means for detecting an actual angle of the steering wheel, wherein the abnormal steering wheel angle detecting means comprises the steering means. And detecting an abnormal steering wheel angle based on a deviation between a target angle of the steering wheel corresponding to the operation amount of the steering wheel and an actual angle of the steering wheel.
[0009]
According to a third aspect of the present invention, there is provided the steering control system for a vehicle according to the first aspect, further comprising a load detecting unit that detects a driving load of the steering wheel driving unit, and the steering wheel angle abnormality detecting unit includes the load detection unit. The steering wheel angle abnormality is detected based on the driving load detected by the means.
[0010]
According to a fourth aspect of the present invention, there is provided the vehicle steering control system according to any one of the first to third aspects, wherein the steering control system is connected to the steering means to provide a driver with a sense of response during steering. A force generating means is provided, and the warning means issues a warning by vibrating the steering means by the reaction force generating means.
[0011]
According to a fifth aspect of the present invention, there is provided a steering system control method for a vehicle for controlling the direction of a steered wheel according to an operation amount of a steering means, wherein a control object to be controlled when the angular position of the steered wheel is controlled. Based on the monitoring result of the state quantity, detecting a steering wheel angle abnormality that cannot control the steered wheels in a direction corresponding to the operation amount of the steering means, and issuing an alarm when the steering wheel angle abnormality is detected. I do.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a first embodiment in which the present invention is embodied in a steer-by-wire system mounted on a vehicle will be described in detail with reference to FIGS.
[0013]
FIG. 1 shows a conceptual diagram of the present embodiment. The steer-by-wire system according to the present embodiment includes a steering wheel unit 100, a reaction motor drive control unit 200, a steering wheel drive control unit 300, and a steering mechanism 400.
[0014]
(Steering wheel unit 100)
The steering wheel 10 (steering means) of the steering wheel unit 100 is connected to a rotating shaft 11 rotatably supported on a vehicle frame (not shown). The reaction force motor 12 is attached to the rotating shaft 11 and applies a steering reaction force to the steering wheel 10. The reaction motor 12 is constituted by a drive motor (for example, a brushless DC motor) having an output shaft integrated with the rotating shaft 11.
[0015]
The elastic mechanism 13 is connected between an end of the rotating shaft 11 opposite to the steering wheel 10 and a vehicle frame (not shown). The elastic mechanism 13 is composed of an elastic member such as a spiral spring. Even when the reaction motor 12 does not apply torque to the steering wheel 10, the elastic mechanism 13 returns the steering wheel 10 to the neutral position (straight forward steering position) by its elastic force.
[0016]
The rotating shaft 11 is provided with a steering angle sensor 14 as operation amount detecting means, and the steering angle sensor 14 detects a steering angle of the steering wheel 10 corresponding to the rotation angle (operation amount) of the rotating shaft 11. . In addition, for convenience of description, the rotation angle may be hereinafter also referred to as a steering wheel rotation angle. Further, a torque sensor 15 is provided on the rotating shaft 11, and the torque sensor 15 detects an operation torque applied to the steering wheel 10. Output signals from the steering angle sensor 14 and the torque sensor 15 are input to the sensor information processing unit 16. The sensor information processing unit 16 converts a signal input from the steering angle sensor 14 into steering wheel angle data, and converts a signal input from the torque sensor 15 into steering wheel torque data.
[0017]
(Reaction motor drive control unit 200)
Next, the reaction motor drive control unit 200 will be described.
The reaction force motor drive control section 200 includes a reaction force motor control circuit 20 and a reaction force motor drive circuit 21. The reaction force motor control circuit 20 is connected to the sensor information processing unit 16 and controls the reaction force motor 12 mainly based on handle angle data and handle torque data obtained from the sensor information processing unit 16. Specifically, a torque to be generated by the reaction force motor 12 is calculated based on the handle angle data and the handle torque data, and a current command value corresponding to the calculated torque is sent to the reaction force motor drive circuit 21. The reaction motor drive circuit 21 generates a PWM waveform by switching the power transistor according to the current command value, and supplies the PWM waveform to the reaction motor 12. The “reaction force generating means” in the claims corresponds to the reaction force motor drive control unit 200 and the reaction force motor 12. The reaction force motor 12 corresponds to an actuator.
[0018]
(Steering wheel drive control unit 300)
Next, the steering wheel drive control unit 300 will be described.
The steering wheel drive control unit 300 includes a steering wheel control circuit 30, a steering wheel drive circuit 31, and a steering wheel angle detection circuit 32.
[0019]
The steering wheel control circuit 30 controls the direction of the steering wheel (steering wheel angle) according to the steering wheel angle data obtained from the sensor information processing unit 16. Specifically, the steering wheel control circuit 30 calculates an ideal angle (target angle) of the steering wheel according to the steering wheel angle data, and calculates the target angle and the actual steering wheel angle (hereinafter, the actual angle or the steering angle) of the steering wheel. A current command is sent to the steering wheel drive circuit 31 in accordance with a deviation from the actual steering wheel angle (hereinafter, referred to as an angle deviation). The steering wheel drive circuit 31 supplies a drive current to the steering mechanism 400 according to this command. A hole CT33 is provided on a power supply line through which a drive current flows, and an output signal of the hall CT33 is fed back to the steering wheel drive circuit 31. The information on the actual angle of the steered wheels is processed by a steering wheel angle detection circuit 32 based on a signal from an angle detector 43 of the steering mechanism 400 and fed back to the steering wheel control circuit 30.
[0020]
FIG. 2 shows the configuration of the steered wheel control circuit 30.
As shown in FIG. 1, the steering wheel control circuit 30 mainly includes a CPU 101 serving as a central processing unit, a ROM 101 storing a program to be executed by the CPU 110, and a RAM 102 storing data necessary for executing the program. Elements. Further, the steering wheel control circuit 30 includes an I / F 103 as an interface circuit with the sensor information processing unit 16, an I / F 104 as an interface circuit with the steering wheel drive circuit 31, and an interface with the steering wheel angle detection circuit 32. An I / F 105 as a circuit is a main component.
[0021]
(Steering mechanism 400)
Next, the steering mechanism 400 will be described.
The steering mechanism 400 includes a motor unit 40 including a stator 41, a motor shaft 42, and an angle detector 43. The stator 41 has an electric winding that generates a magnetic field by a driving current supplied from the steering wheel driving circuit 31. On the other hand, a magnet (not shown) is arranged on the outer edge of the motor shaft 42, and a torque is generated by the action of the magnet and the magnetic field generated by the driving current, so that the motor shaft 42 rotates. A ball screw mechanism 44 is provided at one end of the motor shaft 42. A shaft 45 is screwed into the ball screw mechanism 44, and when the motor shaft 42 rotates, the shaft 45 moves in the left-right direction in FIG. The shaft 45 is connected to a tire T of a front wheel of a vehicle, which is a steering wheel, via a tie rod (not shown). That is, the rotation angle of the motor shaft 42 changes the steering angle of the tire T.
[0022]
Although the basic configuration of the present embodiment is the same as that of the conventional one, the present invention provides a steering wheel angle abnormality indicating that the tire T cannot be controlled to the target angle, such as when the tire T is taken in a groove. It is characterized by the processing when the error occurs. Hereinafter, this problem will be described, and the problem solving means according to the present embodiment will be described.
[0023]
The solid line in FIG. 3A shows a state where the tire T is fitted in the groove G. In FIG. 3A, the upper part of the drawing corresponds to the front part of the vehicle. When the driver turns the steering wheel 10 to the left in such a state, steering wheel angle data indicating the angle is transmitted from the sensor information processing unit 16 to the steered wheel control circuit 30. The steering wheel control circuit 30 attempts to control the tire T to a target angular position (the position indicated by a dotted line in FIG. 3A) calculated from the steering wheel angle data. At the position shown by the solid line. That is, a deviation of θ occurs in the angle of the tire T. On the other hand, since the steering wheel 10 is at an angle corresponding to the target angle position, the driver recognizes that the tire T is oriented in the direction shown by the dotted line. When the vehicle is started in this state, the vehicle travels in a direction different from the driver's intention. This problem is specific to vehicles using a steer-by-wire system. A similar problem also occurs when the tire T hits the curb R as shown in FIG. In FIG. 3B, the dotted line indicates the target angular position of the tire T calculated from the steering wheel angle data as in FIG. 3A, and the solid line indicates the case where the actual tire T is located. ing.
[0024]
FIG. 4 shows “steering wheel rotation angle” and “steering” when the tire T hits an obstacle (for example, groove G or curb R) and cannot be steered while the driver operates the steering wheel 10 in the vehicle according to the present embodiment. The graph shows changes in the state quantities of the wheel actual angle, the angle deviation, and the reaction motor output torque. Among them, the “angle deviation” corresponds to a state quantity to be controlled, which is a control target.
[0025]
The vertical axis shows these state quantities, and the horizontal axis shows time. Hereinafter, the phenomenon will be described for each time domain.
(Time t0 to t1)
t0 is a time when the driver starts operating the steering wheel, and t1 is a time when the tire T hits an obstacle. During the period from t0 to t1, the “steering wheel rotation angle” changes due to the operation of the steering wheel, and accordingly, the “steering wheel actual angle” follows by the processing of the steering wheel drive control unit 300. “Angle deviation” occurs according to the load amount when steering the tire T. In addition, the operation of the reaction motor drive control unit 200 generates a “reaction motor output torque”, and the reaction force in the direction opposite to the rotation direction is transmitted to the steering wheel 10. This reaction force gives the driver a sense of response.
[0026]
(Time t1 to t2)
t2 is a time when the “angle deviation” exceeds a predetermined threshold S1. Since the tire T hits an obstacle at the time t1, the time period from the time t1 to the time t2 is a time zone in which the steering wheel 10 is cut but the tire T does not follow. Accordingly, during this time, the “angle deviation” gradually increases. Further, the reaction motor drive control unit 200 increases the “reaction motor output torque” in accordance with the “angle deviation”, and attempts to return the steering wheel 10 to a position corresponding to the actual angle of the tire T.
[0027]
(Time t2 to t3)
When the “angle deviation” exceeds the predetermined threshold value S1 at time t2, it is determined (detected) that the steering wheel angle abnormality of the tire T has occurred in the processing of the steering wheel control circuit 30, and the reaction force motor drive control unit 200 is alerted. Generate. The reaction force motor drive control unit 200 controls the drive of the reaction force motor 12 and slightly vibrates the “reaction force motor output torque” from when the warning is issued to when the warning is canceled. The driver recognizes that an alarm is being issued by this minute vibration. The period of the fine vibration may be in the range of 0.1 to 1 second, but is preferably in the range of 0.2 to 0.5 second. The width of the minute vibration may be such that the driver can sense the vibration of the steering wheel 10 and does not startle the driver. In addition, the present invention is not limited to the fine vibration, and may be a pulse-like vibration in addition to a sinusoidal vibration.
[0028]
When the driver notices an abnormality, the driver starts to return the steering wheel 10 at time t3.
(Time t3 to t4)
Time t4 is a time at which the “angle deviation” falls below a predetermined threshold value S1 due to the returning operation of the steering wheel 10. When the "angle deviation" falls below the threshold value S1, an alarm release is commanded by the processing of the steering wheel control circuit 30, and the slight vibration of the steering wheel 10 stops.
[0029]
(Time t4 to t5)
Time t5 is the time when the driver finishes returning the steering wheel 10. When the driver stops operating the steering wheel 10, the “angle deviation” becomes substantially zero, and the “reaction motor output torque” becomes a constant value corresponding to the “steering wheel rotation angle”.
[0030]
FIG. 5 shows a flowchart of a process related to the determination of an abnormal steering wheel angle and the generation / cancellation of an alarm performed as a process of the CPU 110 of the steering wheel control circuit 30 in the above series of operations, and will be described in detail below.
[0031]
In the process of step S100, it is determined whether an alarm is being generated. If the alarm is not occurring, the process of step S130 is executed. In step S130, it is determined whether or not the angle deviation is equal to or greater than threshold value S1. If the angle deviation is equal to or larger than the threshold value S1, an instruction to generate an alarm is issued to the reaction force motor drive control unit 200 in step S140, and an alarm is generated. If the angle deviation is not equal to or larger than the threshold value S1, nothing is performed, and this flowchart is temporarily terminated. On the other hand, if it is determined in step S100 that an alarm is being generated, the process of step S110 is executed. In step S110, it is determined whether or not the angle deviation is less than the threshold value S1. If the angle deviation is less than the threshold value S1, an alarm cancellation instruction is issued to the reaction force motor drive control unit 200 in step S120, and the alarm is stopped. If the angle deviation is equal to or larger than the threshold value S1, this flowchart is ended without canceling the alarm. The processing of the flowchart in FIG. 5 is repeatedly executed at a predetermined cycle regardless of the state of the steering system.
[0032]
Thus, in the present embodiment, the “steering wheel control means” in the claims corresponds to the steering wheel control circuit 30, the “steering wheel driving means” corresponds to the steering wheel driving circuit 31 and the steering mechanism 400, The “steering wheel angle detecting means” corresponds to the angle detector 43 and the steering wheel angle detecting circuit 32. The “warning means” corresponds to the reaction motor drive control unit 200 and the reaction motor 12. The “steering wheel angle abnormality detecting means” is realized as processing performed by the CPU 110 of the steering wheel control circuit 30. That is, the CPU 110 corresponds to a steering wheel angle abnormality detection unit.
[0033]
As described above, the steering control system according to the present embodiment has the following effects.
(1) If the direction of the tire T cannot be changed to an angle corresponding to the rotation angle (operation amount) of the steering wheel 10, a warning is issued to the driver, so the driver notices an abnormality and returns the steering wheel. Therefore, it is possible to prevent the vehicle from traveling in a direction not intended by the driver.
[0034]
(2) An abnormal steering wheel angle can be detected based on an angular deviation between an ideal angle (target angle) of the steering wheel calculated from the steering wheel angle data obtained from the sensor information processing unit 16 and the actual angle of the steering wheel. Therefore, the abnormality determination can be performed easily and reliably.
[0035]
(3) The warning to the driver is made by the minute vibration of the torque generated by the reaction motor 12. When the steering wheel angle abnormality of the tire T occurs, the driver always grips the steering wheel 10, so that a warning can be reliably transmitted to the driver.
[0036]
Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, the abnormality determination of the steering wheel angle in the first embodiment is performed based on the driving load at the time of driving the steering wheel. In other respects, the configuration is the same as that of the first embodiment. It has become. Therefore, only the difference will be described below, and the same parts as those in the first embodiment will be denoted by the same reference numerals and redundant description will be omitted.
[0037]
FIG. 6 is a graph in which “angle deviation” is replaced with “steering wheel drive load” in the graph showing the change of the state quantity shown in FIG. The “steering wheel driving load” is a load for driving the motor unit 40 and is detected by the processing of the CPU 110 of the steering wheel control circuit 30. Specifically, it is obtained by calculation according to the drive current detected by the hall CT 33 or the current command value to the steering wheel drive circuit 31. That is, the “load detecting means” in the claims is realized as processing performed by the CPU 110 of the steering wheel control circuit 30.
[0038]
The steering wheel driving load corresponds to a driving load of a steering wheel driving unit. The drive load corresponds to a control target state quantity to be controlled.
At times t0 to t1, a drive current is supplied to the motor unit 40 to steer the steered wheels according to the change in the “steering wheel rotation angle”, and a drive load is generated. After the rising of the driving load, a substantially constant driving load is generated until time t1 when the steered wheels hit the obstacle. When the steered wheels hit an obstacle at time t1, the driving load increases to control the steered wheels to a target angle corresponding to the "steering wheel rotation angle", and eventually exceeds the threshold value S2 (time t2). An alarm is issued by the slight vibration of the steering wheel 10 due to the drive load exceeding the threshold value S2. The driver recognizes the abnormality by this warning and starts to return the steering wheel 10 (time t3). Then, the “steering wheel drive load” rapidly decreases and falls below the threshold value S2 (time t4a). Thereby, the warning is released. Thereafter, in order to advance the steered wheel angle in the reverse direction, the "steered wheel drive load" becomes a negative value, and when the "steering wheel rotation angle" does not change, the "steered wheel drive load" becomes zero (time t5).
[0039]
FIG. 7 shows a flowchart of the processing related to the determination of the abnormal steering wheel angle and the generation / release of the alarm performed in this process. In the flowchart of FIG. 5, the CPU 110 of the steering wheel control circuit 30 determines whether an alarm has been issued / released based on the angle deviation in the flowchart of FIG. 7 according to the driving load. Step S200 is processing to determine whether or not an alarm is being generated. If the alarm is not being generated, the process of step S230 is executed to determine whether the driving load is equal to or greater than the threshold value S2. If the driving load is equal to or greater than the threshold value S2, an instruction to generate an alarm is issued to the reaction force motor drive control unit 200 in step S240, and an alarm is generated. If the driving load is not equal to or more than the threshold value S2, nothing is performed, and this flowchart is temporarily ended. On the other hand, when it is determined in step S200 that the alarm is being generated, the process of step S210 is performed, and it is determined whether the driving load is less than the threshold value S2. If the driving load is less than the threshold value S2, an instruction to cancel the alarm is issued to the reaction force motor drive control unit 200 in step S220, and the alarm is canceled. If the driving load is equal to or more than the threshold value S2, the flowchart is temporarily terminated without canceling the alarm. This series of processing is repeatedly executed at a predetermined cycle regardless of the state of the steering system.
[0040]
Therefore, according to the present embodiment, an abnormality in the steering wheel angle is detected based on the driving load, and a warning is issued to the driver, so that the same effects as in the above (1) and (3) are obtained. In addition, since a steering wheel angle abnormality can be detected based on a driving load for driving the steering wheel, the abnormality determination can be easily and reliably performed. Furthermore, since the alarm is released earlier when the driver starts to return the steering wheel 10, the driver can immediately recognize the validity of the operation of returning the steering wheel 10.
[0041]
The above embodiments can be modified and implemented in the following different forms.
The control target state quantity to be monitored for detecting the abnormal steering wheel angle is not limited to the angular deviation and the steering wheel drive load, but may be the load of the reaction force generating means (reaction motor output torque). . Since the load on the reaction force generating means increases in accordance with the difference between the target angle corresponding to the steering wheel rotation angle and the actual steering wheel angle, for example, a predetermined ratio (preferably, a continuous maximum torque that can be output by the reaction force motor) (80% to 95%), the steering wheel angle abnormality may be detected when the threshold value is exceeded. This modified example also has the same effects as the above (1) and (3). Further, the modified example and the invention described in claim 4 may be implemented in combination.
The vibration of the steering means by the reaction force generating means as a warning is not limited to continuous vibration, but may be intermittent vibration. Also, impact-like vibrations generated at predetermined time intervals may be used. Alternatively, the strength of vibration (amplitude, vibration cycle, or vibration generation interval) is increased in accordance with the angle deviation or the excess rate when the steering wheel drive load exceeds the threshold (the angle deviation or the ratio of the steering wheel drive load to the threshold). It may be something. In this way, when the steering wheel angle abnormality occurs, the vibration intensity increases as the angle deviation or the steering wheel driving load increases, so the driver can more clearly recognize that the operation of the steering means is the cause of the alarm. it can.
The warning means for the driver may be a buzzer, a warning light, or a voice message output device. According to the voice message output device, a voice message is issued, and the driver can more clearly recognize the content of the abnormality and the coping method.
The determination of the steering wheel angle abnormality of the tire T may be a determination based on the and condition by combining the “angle deviation” and the “steering wheel driving load”. Further, it may be determined that the steering wheel angle is abnormal when the state quantities to be controlled suddenly change. Furthermore, when the “angle deviation” or the “steering wheel driving load” changes abruptly as compared with the change amount of the “actual steering wheel angle”, it may be determined that the steering wheel angle is abnormal. According to these determination methods, the steering wheel angle abnormality can be determined more accurately.
[0042]
Next, technical ideas other than the inventions described in the claims, which can be understood from the above embodiments, will be described below together with their effects.
(A) In the vehicle steering system control method according to claim 5, a target angle of the steered wheels corresponding to an operation amount of the steering means is calculated, and based on a deviation between the target angle and an actual angle of the steered wheels. A steering system control method, comprising: determining a steering wheel angle abnormality. This has the same effect as the second aspect of the invention.
(B) The method for controlling a vehicle steering system according to claim 5, wherein a driving load at the time of steering the steering wheel is detected, and a steering wheel angle abnormality is determined based on the detected driving load. Steering system control method. This has the same function and effect as the third aspect of the invention.
(C) In the vehicle steering system control method according to any one of (5) or (A) or (B), a reaction force coupled to the steering means for giving a driver a feeling of steering response. A steering system control method, wherein a warning is issued to a driver by vibrating the steering means by a generation means. This has the same effect as the fourth aspect of the invention.
[0043]
【The invention's effect】
As described above, according to the first or fifth aspect of the present invention, a warning is issued to a driver when a steering wheel angle abnormality occurs in which a steering wheel cannot be controlled in a direction corresponding to the operation amount of the steering means. Since it emits, it is possible to prevent the driver from further cutting the steering means and to prompt the returning operation of the steering means. Thus, it is possible to provide a reaction force generating means that does not need to include a large-capacity actuator, and it is possible to reduce the size, weight, and cost of the steering control system.
[0044]
According to the second aspect of the present invention, the abnormality of the steering wheel angle is detected based on the deviation between the ideal angle (target angle) of the steering wheel corresponding to the operation amount of the steering means and the actual angle of the steering wheel. Therefore, the abnormality determination can be performed easily and reliably.
[0045]
According to the third aspect of the present invention, a steering wheel angle abnormality can be detected by a driving load for driving a steering wheel, so that abnormality determination can be performed easily and reliably.
[0046]
According to the fourth aspect of the present invention, a warning is issued to the driver by vibrating the steering means by the reaction force generating means connected to the steering means. Therefore, it is necessary to provide a special device for issuing a warning. Therefore, an alarm can be reliably transmitted to the driver.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an overall configuration of a steer-by-wire system according to an embodiment.
FIG. 2 is a schematic diagram showing a configuration of a steering wheel control circuit 30.
FIGS. 3A and 3B are explanatory diagrams showing a state in which a tire T has hit an obstacle.
FIG. 4 is a diagram showing a relationship between each state quantity and a steering wheel rotation angle in the first embodiment.
FIG. 5 is a flowchart showing a procedure of abnormality determination and alarm generation / cancellation in the first embodiment.
FIG. 6 is a diagram showing a relationship between each state quantity and a steering wheel rotation angle in the second embodiment.
FIG. 7 is a flowchart showing a procedure of abnormality determination and alarm generation / cancellation in the second embodiment.
[Explanation of symbols]
100 ... steering wheel
10 ・ ・ ・ Steering wheel
11 ... Rotary axis
12 ... Reaction force imparting motor
13 ・ ・ ・ Elastic mechanism
14... Steering angle sensor (operation amount detection means)
15 ... Torque sensor
16 ... Sensor information processing unit
110... CPU (steering wheel angle abnormality detecting means, load detecting means)
200: reaction force motor drive control unit (constitutes alarm means and reaction force generation means with reaction force motor 12)
20 ... Reaction force motor control circuit
21 ... Reaction motor drive circuit
300: Steering wheel drive control unit
30 ... steering wheel control circuit (steering wheel control means)
31 ... steering wheel drive circuit
32 ... steering wheel angle detection circuit
400... Steering mechanism (constitutes steering wheel drive means with steering wheel drive circuit 31)
40 ・ ・ ・ Motor part
41 ・ ・ ・ Stator
42 ・ ・ ・ Motor shaft
43 ··· Angle detector (constitutes steering wheel angle detection means with steering wheel angle detection circuit 32)
44 ・ ・ ・ Ball screw mechanism
45 ... shaft
T: tire
G: groove
R: curb

Claims (5)

Operation amount detection means for detecting the operation amount of the steering means, steering wheel drive means for driving and changing the direction of the steered wheels, and instructing the steering wheel drive means in accordance with the operation amount of the steering means, Steering wheel control means for controlling the direction of the vehicle, the steering control system of the vehicle comprising:
Steering wheel angle abnormality detection for detecting a steering wheel angle abnormality in which the steering wheel cannot be controlled in a direction corresponding to the operation amount of the steering means based on a monitoring result of a control target state quantity to be controlled by the steering wheel control means. Means,
And a warning means for issuing a warning when the steering wheel angle abnormality is detected by the steering wheel angle abnormality detecting means. The vehicle steering control system according to claim 1,
A steering wheel angle detecting means for detecting an actual angle of the steered wheels,
The steering wheel angle abnormality detecting means detects a steering wheel angle abnormality based on a deviation between a target angle of the steered wheels corresponding to an operation amount of the steering means and an actual angle of the steered wheels. system. The vehicle steering control system according to claim 1,
A load detecting unit that detects a driving load of the steering wheel driving unit,
The steering control system according to claim 1, wherein the steering wheel angle abnormality detecting means detects a steering wheel angle abnormality based on the driving load detected by the load detecting means. The steering control system for a vehicle according to any one of claims 1 to 3,
A reaction force generating means coupled to the steering means for giving a driver a sense of response during steering;
The warning control means issues a warning by vibrating the steering means by the reaction force generating means. In a vehicle steering system control method for controlling the direction of a steered wheel according to an operation amount of a steering means,
Based on the monitoring result of the control target state quantity to be controlled when controlling the direction of the steered wheels, a steering wheel angle abnormality that cannot control the steered wheels in a direction corresponding to the operation amount of the steering means is detected, A method for controlling a steering system of a vehicle, wherein an alarm is issued when a steering wheel angle abnormality is detected.

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