JP2008168840A - Vehicle steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular steering device capable of increasing and decreasing a rudder angle of a wheel with easy operation according to a driver's intention. <P>SOLUTION: The rudder angle of the wheel is changed according to a steering angle given by the driver's operation of a steering wheel 7. When grips 9L, 9R attached to a steering wheel body 8 is operated concurrently with the steering wheel 7 being operated, turning motion of a vehicle can be promoted or suppressed because a relation between the steering angle of the steering wheel 7 and the rudder angle of the wheel is changed according to an amount of operation of the grips 9L, 9R detected by grip rotation angle sensors SdL, SdR. In this case, since the grips 9L, 9R are collectively attached to the steering wheel body 8, an operating burden on the driver can be alleviated when compared with the case where they are separately attached. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle steering apparatus that changes a turning angle of a wheel according to a steering angle of a steering wheel operated by a driver.

The motor is fixed to the steering wheel, the first gear fixed to the output shaft of the motor is engaged with the second gear fixed to the steering shaft, and the motor is driven when the steering wheel is steered by the driver. Japanese Patent Application Laid-Open Publication No. 2004-151867 discloses a technique in which the relationship between the steering angle and the steering angle of a wheel can be changed.
JP 2005-35363 A

  By the way, in the conventional system, the electronic control unit predicts the vehicle behavior desired by the driver from the vehicle motion state and the vehicle operation system state, and the motor is controlled based on the predicted behavior. Although the relationship with the turning angle has been changed, the vehicle behavior desired by the driver is not always the same as that predicted by the electronic control unit depending on the road conditions, etc., and the intended turning angle of the wheel cannot be obtained. Therefore, the driver may feel uncomfortable.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle steering apparatus that can increase or decrease the turning angle of a wheel according to the driver's intention with a simple operation.

  In order to achieve the above object, according to the first aspect of the present invention, in the vehicle steering apparatus for changing the turning angle of the wheel according to the steering angle of the steering wheel operated by the driver, the steering wheel A grip provided on a main body and operated by a driver, and a steering actuator that changes a relationship between a steering angle of the steering wheel and a turning angle of the wheel according to an operation amount of the grip. A vehicle steering apparatus is proposed.

  The front wheels WFL and WFR in the embodiment correspond to the wheels of the present invention.

  According to the configuration of claim 1, when the driver operates the steering wheel, the turning angle of the wheel changes according to the steering angle. If you operate the grip on the steering wheel body in parallel with the steering wheel operation, the relationship between the steering angle of the steering wheel and the turning angle of the wheel will change according to the amount of operation. Can be assisted or suppressed. At this time, since the grip is provided on the steering wheel body, the operation burden on the driver is reduced as compared with the case where they are provided separately.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 to 3 show a first embodiment of the present invention. FIG. 1 is a diagram showing an overall configuration of a vehicle equipped with a steering device, FIG. 2 is a perspective view of a steering wheel, and FIG. 3 is a control system. FIG.

  As shown in FIG. 1, a four-wheel vehicle equipped with the steering device of the present embodiment includes left and right front wheels WFL, WFR as drive wheels to which the driving force of engine E is transmitted via transmission T, Left and right rear wheels WRL, WRR, which are driven wheels that rotate as the vehicle travels, are provided. The left and right front wheels WFL, WFR are steered by SBW (steer-by-wire). That is, the steering wheel 7 and the steering gear box 6 are not mechanically connected, and the operation of the steering wheel 7 by the driver is converted into an electric signal, and the steering gear box 6 is operated by the steering actuator 5 to move the front wheel. Steer WFL and WFR. The electronic control unit U that controls the operation of the steering actuator 5 includes a steering angle sensor Sa that detects the steering angle of the steering wheel 7, a vehicle speed sensor Sb that detects the vehicle speed, a lateral acceleration sensor Sc that detects lateral acceleration, Grip rotation angle sensors SdL and SdR described later are connected.

  The vehicle speed sensor Sb and the lateral acceleration sensor Sc are not used in the first embodiment, but are used in the second embodiment.

  As shown in FIG. 2, the steering wheel 7 includes an annular steering wheel main body 8, and the two positions that the driver grips with the left and right hands are constituted by grips 9 </ b> L and 9 </ b> R that are separate members. Each of the grips 9L and 9R can rotate around the rotation axes 10 and 10 extending in the tangential direction, and the rotation angle is detected by the grip rotation angle sensors SdL and SdR. The grips 9L and 9R are urged toward the neutral position by a return spring (not shown).

  As shown in FIG. 3, the electronic control unit U includes basic turning angle command value calculating means M1, left superimposed turning angle command value calculating means M2L, right superimposed turning angle command value calculating means M2R, An adding means M3, a second adding means M4, and an actuator control means M5 are provided. A steering angle sensor Sa is connected to the basic turning angle command value calculation means M1, and the left and right grip rotation angle sensors SdL, SdR is connected to each other, and the steering actuator 5 is connected to the actuator control means M5.

  Next, the operation of the first embodiment of the present invention having the above configuration will be described.

  The steering angle at which the driver steers the steering wheel 7 to the left and right is detected by the steering angle sensor Sa, and the basic turning angle command value calculation means M1 to which the steering angle is input has a basic turning angle proportional to the steering angle. Calculate the command value. When the driver does not operate the grips 9L, 9R, the actuator control means M5 drives the steering actuator 5 with the command value of the basic turning angle as a target value, and the turning angle of the left and right front wheels WFL, WFR is the basic turning. Match the corner. Thereby, even if the steering wheel 7 and the steering gear box 6 are not mechanically connected, the left and right front wheels WFL, WFR can be steered at a turning angle proportional to the steering angle of the steering wheel 7.

  When the driver rotates the left grip 9L provided at a position where the driver normally holds the steering wheel body 8 with his left hand, the rotation angle of the left grip 9L detected by the left grip rotation angle sensor SdL is changed to the left superimposed rotation of the electronic control unit U. It is input to the steering angle command value calculation means M2L. The left superimposed turning angle command value calculating means M2L calculates a command value for the left superimposed turning angle corresponding to the rotation angle of the left grip 9L. When the driver rotates the right grip 9R provided at a position where the driver normally holds the steering wheel body 8 with the right hand, the rotation angle of the right grip 9R detected by the right grip rotation angle sensor SdR is the right superimposed rotation of the electronic control unit U. It is input to the steering angle command value calculation means M2R. The right superimposed turning angle command value calculating means M2R calculates a command value of the right superimposed turning angle corresponding to the rotation angle of the right grip 9R.

  The left and right superimposed turning angle command value calculation means M2L and M2R calculated by the left and right superimposed turning angle command value calculation means M2L and M2R are added by the first addition means M3. Normally, only one of the left and right grips 9L and 9R is operated. However, when the left and right grips 9L and 9R are operated simultaneously, the left superimposed turning calculated by the left superimposed turning angle command value calculating means M2L. The command value of the angle and the command value of the right superimposed turning angle calculated by the right superimposed turning angle command value calculating means M2R are added and canceled out, and the command value of the superimposed turning angle is the first adding means. Output from M3.

  The superposed turning angle command value output from the first adding means M3 and the basic turning angle command value are added by the second adding means M4 to calculate the final turning angle command value. The actuator control means M5 operates the steering actuator 5 based on the value to generate a turning angle corresponding to the final turning angle command value.

  For example, when a driver who has determined that an understeering tendency occurs during a right turn rotates the right grip 9R, the steering angle in the right direction increases and the understeering tendency can be eliminated. Conversely, when the driver who has determined that there is an oversteer tendency during a right turn rotates the left grip 9L, the steering angle in the left direction increases and the oversteer tendency can be eliminated.

  Even during left turn or straight running, the turning angle can be controlled by operating the left and right grips 9L and 9R.

  As described above, the turning angles of the front wheels WFL and WFR can be adjusted to an arbitrary direction and an arbitrary size only by rotating the left and right grips 9L and 9R that allow a part of the steering wheel body 8 to rotate. Therefore, while turning the vehicle by operating the steering wheel 7, the left and right grips 9L and 9R can be rotated to assist or suppress the turning. At this time, since the left and right grips 9L and 9R can be operated by the driver's hand attached to the steering wheel body 8, the operation burden on the driver is reduced.

  Next, a second embodiment of the present invention will be described based on FIG. 4 and FIG.

  In the second embodiment, the vehicle speed and steering angle sensor Sa detected by the vehicle speed sensor Sb is the sum of the command values of the left and right superimposed turning angles calculated by the left and right superimposed turning angle command value calculating means M2L and M2R. The correction is made by the detected steering angle and the lateral acceleration detected by the lateral acceleration sensor Sc.

  That is, the correction coefficient calculation means M6 to which the vehicle speed detected by the vehicle speed sensor Sb is input calculates the first correction coefficient K1 based on the map of FIG. 5A using the vehicle speed as a parameter. The first correction coefficient K1 takes a maximum value of 1 when the vehicle speed is 0, and gradually decreases from the maximum value when the vehicle speed increases from 0.

  Further, the correction coefficient calculation means M6 to which the steering angle detected by the steering angle sensor Sa is input calculates the second correction coefficient K2 based on the map of FIG. 5B using the steering angle as a parameter. The second correction coefficient K2 takes a minimum value less than 1 when the steering angle is 0, and increases from the minimum value toward 1 when the steering angle increases from 0 to the left and right.

  The correction coefficient calculation means M6 to which the lateral acceleration detected by the lateral acceleration sensor Sc is input calculates the third correction coefficient K3 based on the map of FIG. 5C using the lateral acceleration as a parameter. The third correction coefficient K3 takes a value of 1 when the lateral acceleration is 0, and decreases from 1 when the lateral acceleration increases from 0 to the left and right.

  The command value of the superimposed turning angle output from the first addition means M3 is corrected by the multiplication means M7 by multiplying the first, second, and third correction coefficients K1, K2, and K3, and the corrected superimposed rotation is corrected. The command value of the steering angle and the command value of the basic turning angle are added by the second adding means M4 to calculate the final turning angle command value. Based on the command value, the actuator control means M5 performs the steering. By operating the actuator 5, a turning angle corresponding to the final turning angle command value is generated.

  Therefore, when the vehicle speed is high, the driver is tense and grips the steering wheel 7, so that the driver slightly shakes when operating the grips 9L and 9R, and noise is easily applied to the steering angle command value. . However, the first correction coefficient K1 reduces the first correction coefficient K1 and reduces the turning angle command value at high vehicle speeds, so that fluctuations in the turning angle due to the influence of noise can be reduced. On the contrary, when the vehicle speed is low, the driver does not hold the steering wheel 7 strongly, so that it is difficult for the driver to ride the command value of the turning angle output by the operation of the grips 9L and 9R. At this low vehicle speed, the first correction coefficient K1 increases and the steering angle command value increases, so that it is possible to control the steering angle that sufficiently reflects the driver's intention to operate the grips 9L and 9R.

  Further, since the amount of change in the turning angle is increased according to the increase in the steering angle by the second correction coefficient K2, the amount of change in the turning angle is made small at the small steering angle at which the driver does not intend to turn. This suppresses an undesirable change in vehicle behavior due to erroneous operation of the grips 9L and 9R, and at the time of a large steering angle at which the driver wants to make a sudden turn, the driver operates the steering wheel 7 by increasing the amount of change in the turning angle. The operation burden can be reduced.

  Further, the third correction coefficient K3 decreases the change amount of the turning angle in accordance with the increase of the lateral acceleration. Therefore, when a sudden lateral acceleration occurs, the change amount of the turning angle is reduced to reduce the left and right grips. It is possible to suppress an undesirable change in the vehicle behavior due to erroneous operation of 9L and 9R, and to generate a large lateral acceleration according to the driver's intention when sufficient lateral acceleration is not generated only by operating the steering wheel 7.

  FIG. 6A shows a third embodiment of the second correction coefficient K2. In the third embodiment, in the region where the absolute value of the steering angle is less than the threshold value, the second correction coefficient K2 is uniformly 0, and the superimposed turning angle commanded by the left and right grips 9L, 9R does not occur. In the region where the absolute value of the steering angle is equal to or greater than the threshold value, the second correction coefficient K2 increases instantaneously or gradually from 0 to 1, and finally the total amount of the superimposed turning angle commanded by the left and right grips 9L and 9R is appear.

  FIG. 6B shows a third embodiment of the third correction coefficient K3. In the third embodiment, in the region where the absolute value of the lateral acceleration is less than the threshold value, the third correction coefficient K3 is uniformly 1, and the total amount of the superimposed turning angle commanded by the left and right grips 9L and 9R is generated. . In the region where the absolute value of the lateral acceleration is equal to or greater than the threshold value, the third correction coefficient K3 decreases instantaneously or gradually from 1 to 0, and the superimposed turning angle commanded by the left and right grips 9L and 9R is accordingly finalized. Will not occur.

  Next, a fourth embodiment of the present invention will be described with reference to FIGS.

  The fourth embodiment is a modification of the above-described first embodiment. In the first embodiment, the basic steering of the front wheels WFL and WFR generated based on the operation of the driver's steering wheel 7 is performed. The command value of the superimposed turning angle generated based on the operation of the grips 9L and 9R is added to the command value of the corner to calculate the final turning angle command value. As shown in FIG. In the fourth embodiment, the sum of the left and right superimposed turning angle command values generated based on the operation of the grips 9L and 9R is corrected by the superimposed turning angle command value correcting means M8, and the corrected superimposed rolling is corrected. The final steering angle command value is calculated by adding the steering angle command value to the basic steering angle command value calculated by the automatic steering means M9.

  The automatic steering means M9, for example, drives the steering actuator 5 to follow the preceding vehicle detected by the radar device and performs automatic steering, or drives the steering actuator 5 to avoid contact with an obstacle. One that performs automatic steering and one that drives the steering actuator 5 to perform automatic steering in order to maintain a lane between two white lines are included.

  The superimposed turning angle command value correcting means M8 uses as a parameter the addition value of the left and right superimposed turning angle command value calculating means M2L and M2R calculated by the left and right superimposed turning angle command value calculation means, and based on the map shown in FIG. The command value of the superimposed turning angle corrected by the above is calculated. The corrected command value of the superimposed turning angle is set so that the amount of increase decreases as the parameter increases.

  Also according to the fourth embodiment, the steering angles of the front wheels WFL, WFR can be set in an arbitrary direction during the automatic steering only by rotating the left and right grips 9L, 9R that allow a part of the steering wheel body 8 to rotate. Since it can be adjusted to an arbitrary size, the left and right grips 9L and 9R can be rotated to assist or suppress turning while turning the vehicle by turning the front wheels WFL and WFR by automatic steering. . At this time, since the left and right grips 9L and 9R can be operated by the driver's hand attached to the steering wheel body 8, the operation burden on the driver is reduced.

  Next, a fifth embodiment of the present invention will be described based on FIG. 9 and FIG.

  The fifth embodiment is a modification of the above-described fourth embodiment, and the fifth embodiment is a control instead of the superposed turning angle command value correcting means M8 of the fourth embodiment. Constant calculation means M10 is provided. The control constant calculation means M10 uses the sum of the left and right superimposed turning angle command values calculated by the left and right superimposed turning angle command value calculating means M2L and M2R as a parameter, and searches for the control constant based on the map shown in FIG. To do. The control constant is set so that the increase amount decreases as the parameter increases.

  The control constant functions as a gain when the automatic steering means M9 calculates the command value of the basic turning angle, and the final turning angle command value can be changed by increasing or decreasing the control constant. it can.

  Also according to the fifth embodiment, the same effect as that of the fourth embodiment can be achieved.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, in the embodiment, the rotation angles of the grips 9L and 9R are detected, but the rotation angular speed and the rotation torque of the grips 9L and 9R may be detected.

  Further, the grips 9L and 9R of the steering wheel 7 may be stepless (continuously) rotating or swinging, or may be rotating or swinging stepwise.

  The steering wheel 7 according to the embodiment includes left and right grips 9L and 9R. However, a single grip that is operated with the right hand or the left hand is provided, and the grip is rotated in two directions, forward and reverse, from the neutral position. The generation of the turning angle and the left turning angle may be commanded.

  Further, if the grips 9L and 9R are made of a flexible material so that the steering wheel body 8 maintains a circular shape even when the grips 9L and 9R are rotated, the operability is further improved.

The figure which shows the whole structure of the vehicle carrying the steering device which concerns on 1st Embodiment. Steering wheel perspective view Block diagram of control system Block diagram of a control system according to the second embodiment The figure which shows the map which searches the 1st-3rd correction coefficient The figure which shows the map which searches the 2nd, 3rd correction coefficient which concerns on 3rd Embodiment. Block diagram of control system according to fourth embodiment The figure which shows the map which searches the correction amount of the command value of superposition turning angle Block diagram of control system according to fifth embodiment Diagram showing a map to search for control constants

Explanation of symbols

5 Steering actuator 7 Steering wheel 8 Steering wheel body 9L Left grip 9R Right grip WFL Front wheel (wheel)
WFR Front wheel (wheel)

Claims (1)

In a vehicle steering apparatus that changes a turning angle of a wheel (WFL, WFR) according to a steering angle of a steering wheel (7) operated by a driver,
Grips (9L, 9R) provided on the steering wheel body (8) and operated by the driver;
A steering actuator (5) for changing a relationship between a steering angle of the steering wheel (7) and a turning angle of the wheels (WFL, WFR) according to an operation amount of the grip (9L, 9R);
A vehicle steering apparatus comprising:

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