JPH0692250A - Steering gear - Google Patents

Abstract

PURPOSE:To stably control the direction of a vehicle with high follow-up prop erty to the operation of steering wheel over a wide range from low vehicle speed to high vehicle speed in a steering gear for controlling the azimuth of the advancing vehicle with the steering angle of the steering wheel. CONSTITUTION:An indicating angle theta inputted from a steering wheel by a steering indicating angle detecting means 4 is detected to obtain a desired azimuth value phiM through a steering indicating angle.azimuth corresponding means 11. The azimuth deviation E of the desired azimuth valve phiM from the present orientation phi of advancing vehicle is supplied to a steering angle specifying means 14 which is set so as to reduce a steering angle delta outputted along with the increase of vehicle speed V and increase the increase rate of a steering angle along with the increase of the azimuth deviation E in relation between the azimuth deviation E and steering angle delta. The steering angle deltaoutput is supplied to a steering mechanism driving means 16 through a low pass filter means 15 to steer wheels through a steering mechanism 8 for controlling the direction of the vehicle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering system in which a traveling azimuth angle of a vehicle is controlled by operating a steering wheel.

[0002]

2. Description of the Related Art The applicant of the present invention has proposed, in Japanese Patent Application Laid-Open No. 1-233170, a steering device having a steering method which is completely different from the conventional steering operation. This steering device controls the traveling azimuth of the vehicle with the operation angle of the steering wheel, thereby eliminating the need for the steering wheel turning back operation, and intends to steer the vehicle with fewer steering wheel operations. This conventional steering apparatus is a power steering system in which the deviation between the amount of change in the traveling direction input using the steering instruction means (handle) and the amount of change in the traveling direction detected by the traveling direction detection means becomes zero. It is configured to steer the device.

[0003]

When controlling the azimuth of the vehicle in proportion to the steering wheel angle in this way, if there is a delay in following the direction of the vehicle with respect to the operation of the steering wheel, the steering wheel angle and the vehicle Since the correspondence with the azimuth angle is not established, the behavior of the vehicle cannot be grasped and the vehicle cannot be properly steered. If the relationship between the azimuth deviation and the actual steering angle (δ) of the vehicle is uniquely set regardless of the vehicle speed, the vehicle will follow the direction until it reaches the desired direction during low-speed traveling with a large operating angle. It is not possible to achieve both good driving performance and elimination of sensitive followability at high speeds.

The present invention has been made to solve the above problems, and stably controls the direction of the vehicle in response to the steering wheel operation over a wide range from low vehicle speed to high vehicle speed. An object of the present invention is to provide a steering device capable of performing the above.

[0005]

In order to solve the above-mentioned problems, the invention according to claim 1 detects steering direction instructing means for instructing the amount of change in the traveling direction of a vehicle with respect to a reference direction, and detecting the amount of change in the traveling direction of the vehicle. A traveling direction detecting means, and a control means for controlling the steering mechanism so that the azimuth angle deviation between the traveling direction change amount input from the steering instruction means and the traveling direction change amount of the vehicle detected by the traveling direction detection means becomes zero. In the steering apparatus including the above, the control unit includes a steering angle designating unit that outputs a signal related to the steering angle based on the azimuth angle deviation, and the steering angle designating unit decreases the steering angle that is output as the vehicle speed increases. It is characterized in that it is configured to.

According to a second aspect of the present invention, steering instruction means for instructing the amount of change in the traveling direction with respect to the reference direction of the vehicle, traveling direction detecting means for detecting the amount of change in the traveling direction of the vehicle, and input from the steering instruction means. In the steering device including the control means for controlling the steering mechanism so that the azimuth deviation between the traveling direction change amount and the traveling direction change amount of the vehicle detected by the traveling direction detection means becomes zero, the control means comprises: The steering angle designating means outputs a signal relating to the steering angle based on the azimuth deviation, and the steering angle designating means determines the relationship between the deviation and the steering angle to be output with the increase rate of the steering angle as the azimuth deviation increases. Is set to be large.

It should be noted that the steering angle may be supplied from the steering angle designating means to the steering mechanism via the low-pass filter means.

The time constant of the low-pass filter means may be changed according to the steering angle.

[0009]

In the steering system according to the first aspect of the present invention, the steering angle output is reduced as the vehicle speed increases, so that the azimuth control of the vehicle is sufficiently responsive to the operation of the steering instruction means (steering wheel) at low vehicle speeds. Therefore, it is possible to prevent a hypersensitive response when driving at high speed.

According to a second aspect of the present invention, the steering apparatus has a relationship between the output steering angle and the azimuth deviation between the amount of change in the traveling direction input from the steering instruction means and the amount of change in the traveling direction of the vehicle detected by the traveling direction detection means. Is set so that the rate of increase of the steering angle increases as the azimuth deviation increases, so when the azimuth deviation is large, a large steering output is supplied, which improves the responsiveness of the azimuth control of the vehicle and also reduces the steering wheel size. Since the steering output with respect to the operation input is small, the response is not sensitive. That is, maneuverability is stable.

In the steering apparatus according to the third aspect of the present invention, the steering angle output from the steering angle designating means is supplied to the steering mechanism through the low pass filter means. It is possible to save a hypersensitive response to a high frequency operation input.

According to the fourth aspect of the present invention, since the time constant of the low-pass filter means is made different according to the steering angle, the time constant of the low-pass filter means is set in the large steering angle range where high frequency input is difficult to enter. By setting it low, the followability of azimuth control of the vehicle is improved, and in the small rudder angle range where high frequency input is likely to occur, the time constant of the low pass filter means is set high and the cutoff frequency is lowered to increase the high frequency. Can suppress the hypersensitive response to.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block configuration diagram of a control means of a steering device according to the present invention, FIG. 2 is a schematic structural diagram showing an overall structure of the steering device, and FIG. 3 is an example of a relationship between a steering instruction and a vehicle azimuth angle. FIG.

First, the overall structure of the steering apparatus according to the present invention will be described with reference to FIG. The steering device 1 includes a steering instruction angle detecting means 4 and a reaction force applying means 5, which are provided on a steering shaft 3 connected to a steering instruction means (handle) 2, a vehicle speed detecting means 6, and a traveling direction detecting means. Means 7, steering mechanism 8,
And a control means 9. The steering shaft 3 rotatably instructs a vehicle body (not shown) or the like.

The steering instruction angle detection means 4 detects the rotation of the steering shaft 3 by using a rotary encoder or the like, so that the steering instruction angle (handle angle) from a predetermined position of the steering instruction means (handle) 2 ) The signal 4a relating to θ is supplied to the control means 9. In addition, steering instruction angle (handle angle)
θ represents an azimuth angle with this predetermined azimuth as a reference, where the above-mentioned predetermined position is the absolute azimuth such as north, or the current traveling azimuth of the vehicle.

The reaction force applying means 5 applies a steering reaction force to the steering instructing means (handle) 2, and the reaction force generating motor 1 is provided.
0 (see FIG. 1) and a gear mechanism (not shown) are provided to apply a steering reaction force according to the magnitude of the motor current 9a supplied from the control means 9.

The vehicle speed detecting means 6 uses a speedometer and supplies a signal 6a relating to the vehicle speed V to the control means 9. The traveling direction detection means 7 is configured by using a yaw rate gyro or the like, and controls the signal 7a relating to the yaw rate γ by the control means 9.
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The steering mechanism 8 is configured to steer a steering wheel (not shown) based on a steering drive signal 9b output from the control means 9.

The control means 9 receives the signal 4a relating to the steering angle θ, the signal 7a relating to the yaw rate γ, and the signal 6a relating to the vehicle speed V, and controls the polarity and current value of the motor current 9a. A steering reaction force is applied to the steering instruction means (steering wheel) 2 and the azimuth angle φ of the vehicle is controlled corresponding to the steering instruction angle (steering wheel angle) θ as shown in FIG. .

Next, the structure of the control means 9 will be described with reference to FIG. The control means 9 includes a steering instruction angle / azimuth angle correspondence means 11
A vehicle azimuth calculation means 12, a deviation calculation means 13,
The steering angle designating unit 14, the low-pass filter unit 15, the steering mechanism driving unit 16, the reaction force setting unit 17, and the reaction force motor driving unit 18.

The actual steering angle is changed by the operation of the steering mechanism 8 to the vehicle 1.
9 to change the traveling direction of the vehicle 19, and a yaw rate corresponding to the change occurs. Then, the azimuth angle φ of the vehicle is controlled in a form in which the change in the traveling direction of the vehicle 19 is integrated by the integral term 20.

In the case where the vehicle speed detecting means 6 shown in FIG. 1 outputs a pulse signal corresponding to the rotation of the wheels, the vehicle speed is calculated in the control means 9 based on the cycle of the pulse signal and the like. A configuration may be provided in which a vehicle speed calculation unit that outputs a signal related to the vehicle speed V is provided.

The steering instruction angle / azimuth angle correspondence means 11 has a steering instruction angle (steering wheel angle) detected by the steering instruction angle detection means 4.
The signal 11a relating to the azimuth target value φM is output based on the signal 4a relating to θ. The steering instruction angle (steering wheel angle)
The ratio k1 between θ and the azimuth target value φM can be set arbitrarily.

When the ratio k1 is set to 1.0, the steering instruction angle (steering wheel angle) θ becomes equal to the azimuth target value φM. That is, when the steering instruction means (handle) 2 is rotated 180 degrees, if the current heading of the vehicle is north, the azimuth target value φM is changed to south. When the ratio k1 is set to 0.5 and the steering instruction means (handle) 2 is rotated rightward by 180 degrees, the azimuth target value φM is 90 degrees rightward with respect to the traveling direction of the vehicle (for example, traveling direction). Direction from north to east).

The vehicle traveling azimuth angle calculating means 12 outputs a signal 7a relating to the yaw rate γ output from the traveling azimuth detecting means 7.
Is provided and outputs a signal 12a relating to the current traveling direction φ of the vehicle obtained by the integration.

The deviation calculation means 13 outputs a signal 11a relating to the azimuth target value φM output from the steering instruction angle / azimuth angle correspondence means 11 and the current traveling of the vehicle output from the vehicle traveling azimuth angle calculation means 12. An azimuth angle deviation E from the signal 12a relating to the azimuth φ is obtained, and a signal 13a relating to the azimuth angle deviation E (E = φM−φ) is supplied to the steering angle setting means 14.

The steering angle setting means 14 outputs a signal 14a relating to the steering angle δ based on the signal 13a relating to the azimuth angle deviation E and the signal 6a relating to the vehicle speed V detected by the vehicle speed detecting means 6. The rudder angle setting means 14 is composed of, for example, a ROM or the like, and is configured by a conversion table that stores the rudder angle δ set in advance corresponding to each azimuth angle deviation E and each vehicle speed V. The rudder angle setting means 14 may be configured to calculate and output the rudder angle δ based on a pre-registered functional expression or the like.

FIG. 4 is a graph showing the input / output characteristics of the steering angle setting means. The horizontal axis represents the azimuth deviation E which is the input, the vertical axis represents the steering angle δ which is the output, and each characteristic curve shows that the vehicle speed V is 20 / h.
The cases of 30, 40, 50 and 60 kilometers are shown respectively. As shown in FIG. 4, the steering angle designating means 14
Is configured to decrease the steering angle δ that is output as the vehicle speed V increases. This is because the large rudder angle is the main operation in the low vehicle speed range, and a high gain is set to ensure a small turning performance, and the low rudder angle is the main operation in the middle and high speed range, and the gain is set low so that the response is not sensitive. This is because it is set.

Further, each characteristic curve is set by using the exponential function shown in the equation 1 having the characteristic that the rate of increase of the steering angle δ increases as the azimuth angle deviation E increases.

[0030]

[Equation 1]

This is because when the value of the steering instruction input (steering wheel angle) θ is small, the gain is reduced to suppress the hypersensitive response, and steering is performed as the value of the steering instruction input (steering wheel angle) θ becomes large. This is because the output of the angle δ is increased to improve the responsiveness. Not only an exponential function, but also a quadratic function or two proportional functions whose slopes change in a small area and a large azimuth angle deviation E may be used.

The low-pass filter means 15 attenuates the high-frequency component of the signal 15a relating to the steering angle δ output from the steering angle designating means 14, and adds 1 to the signal 15a relating to the steering angle δ.
The signal 15a relating to the steering target value δM given the next delay element (1/1 + τS) is supplied to the steering mechanism drive means 16, and the low pass filter means 15 has a time constant τ according to the magnitude of the steering angle δ. Is configured to be switched in multiple stages.

In this embodiment, as shown in FIG. 4, when the steering angle δ is δ1 degrees or less, the time constant τ of the low-pass filter means 15 is τ1 second, and when the steering angle δ exceeds δ1 degrees, the time constant τ is 1 second. τ is set to τ2 seconds, and τ1 is set to be larger than τ2.

FIG. 5 is a graph showing a specific characteristic example of the low-pass filter means. The horizontal axis represents frequency and the vertical axis represents gain. The low-pass filter means 15 is provided to suppress a hypersensitive response. Further, since the time constant τ of the low-pass filter means 15 is made different according to the steering angle δ, the time constant τ2 of the low-pass filter means 15 is set low in a large steering angle range where it is difficult to input a high frequency. In order to improve the followability of the azimuth control of the vehicle, and to set the time constant τ1 of the low-pass filter means 15 to a high value in the small rudder angle range where a high frequency input is likely to enter, the cutoff frequency fC2 is lowered to make it sensitive to high frequencies. Various responses can be suppressed.

The steering mechanism driving means 16 outputs the signal 1 relating to the steering target value δM output from the low-pass filter means 15.
A steering drive signal 9 for driving the steering mechanism 8 based on 5a.
It is configured to output b. When the steering mechanism 8 includes a DC motor, a gear mechanism, and the like, and the steering angle of the vehicle is controlled based on the polarity and the current value of the motor current supplied to the DC motor, the steering mechanism driving means 16 causes the steering target value δM. A preset motor current is supplied with a preset polarity corresponding to. When the steering mechanism 8 is configured by using a pulse motor or the like, the steering mechanism driving means 16 is configured to supply the required number of forward rotation or reverse rotation pulses.

The reaction force setting means 17 outputs a signal 17a relating to the reaction force torque target value T based on the signal 13a relating to the azimuth angle deviation E and the signal 6a relating to the vehicle speed V. The reaction force setting means 17 is composed of, for example, a ROM or the like, and is composed of a conversion table storing a reaction force torque target value T preset corresponding to each azimuth angle deviation E and each vehicle speed V. The reaction force setting means 17 may be configured to calculate and output the reaction force torque target value T based on a previously registered function formula or the like.

FIG. 6 is a graph showing the input / output characteristics of the reaction force setting means. The horizontal axis represents the azimuth deviation E, the vertical axis represents the reaction force torque target value T, and each characteristic represents the case where the vehicle speed V is 0, 10 kilometers, and 20 kilometers per hour. As the vehicle speed V increases, the limit value of the reaction force torque target value T is set larger. Thus, by changing the reaction force torque value T according to the vehicle speed V, an appropriate reaction force is applied to the steering instruction means (handle) 2 according to the vehicle speed V,
It is possible to prevent excessive steering and stabilize the steering.

With the above-described structure, the steering system according to the present invention drives the steering mechanism 8 based on the azimuth angle deviation E between the azimuth angle target value φM and the current traveling azimuth φ of the vehicle to advance the vehicle. Motor 1 for controlling reaction and generating reaction force
The steering reaction force is applied to the steering instruction means (handle) 2 by driving 0.

Here, since the steering angle designating means 14 is configured to decrease the steering angle δ that is output as the vehicle speed V increases, the vehicle in response to the operation of the steering instructing means (handle) 2 during low speed traveling. The responsiveness of the azimuth angle control can be increased, and the behavior of the vehicle can be prevented from becoming irritable when traveling at medium and high speeds.

Further, since the function having the characteristic that the steering angle δ increases with the increase of the azimuth angle deviation E is used for the relationship between the azimuth angle deviation E and the output steering angle δ, the steering instruction means (handle) When the operation angle of 2 is large, a large steering angle output can be obtained, and when the operation angle is small, a small steering angle output can be obtained.
Therefore, when the operation angle is large, the azimuth of the vehicle can be controlled with good responsiveness, and when the operation angle is small, the hypersensitive response can be prevented.

Further, since the steering angle output δ of the steering angle designating means 14 is subjected to the low-pass filter processing, it is possible to suppress a hypersensitive response to a sudden steering wheel operation.

When the steering angle δ is large, the time constant τ of the low-pass filter means 15 is set small, and when the steering angle δ is small, the time constant τ is set large, so that the azimuth angle of the vehicle is large. It is possible to improve the control response and suppress the hypersensitive response in the small steering angle range.

[0043]

As described above, the steering device according to the first aspect of the present invention has a structure in which the steering angle output based on the azimuth angle deviation is decreased as the vehicle speed increases. Therefore, when the vehicle speed is low, the steering instruction means ( It is possible to sufficiently secure the responsiveness of the azimuth control of the vehicle to the operation of the steering wheel) and prevent the hypersensitive response at high vehicle speed.

According to a second aspect of the present invention, the steering apparatus has a relationship between the output steering angle and the azimuth deviation between the amount of change in the traveling direction input from the steering instruction means and the amount of change in the traveling direction of the vehicle detected by the traveling direction detection means. Is a function having a characteristic that the rate of increase of the steering angle increases as the azimuth deviation increases. Therefore, when the operation angle of the steering instruction means (steering wheel) is large, a large steering output is supplied and the azimuth angle of the vehicle is increased. Since the control response is improved and the steering output for a small steering wheel operation input is reduced, it is not a hypersensitive response. That is, maneuverability can be stabilized.

Since the steering apparatus according to the third aspect is configured to supply the steering angle output from the steering angle designating means to the steering mechanism through the low-pass filter means, it is possible to save a sensitive response.

The steering apparatus according to the fourth aspect of the present invention has a structure in which the time constant of the low-pass filter means is made different according to the steering angle. Therefore, for example, by setting the time constant of the low-pass filter means low in the large steering angle range. By improving the followability of the azimuth control of the vehicle and by setting the time constant of the low-pass filter means to be high in the small steering angle range, it is possible to suppress a hypersensitive response.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a control means of a steering device according to the present invention.

FIG. 2 is a schematic structural diagram showing the overall structure of the steering device.

FIG. 3 is an explanatory diagram showing an example of a relationship between a steering instruction and a vehicle azimuth angle.

FIG. 4 is a graph showing the input / output characteristics of the steering angle setting means.

FIG. 5 is a graph showing a specific example of characteristics of the low-pass filter means.

FIG. 6 is a graph showing the input / output characteristics of the reaction force setting means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steering device 2 Steering instruction means (handle) 4 Steering instruction angle detection means 6 Vehicle speed detection means 7 Traveling direction detection means 8 Steering mechanism 9 Control means 11 Steering instruction angle / azimuth correspondence means 12 Vehicle traveling azimuth calculation means 13 deviation calculation means 14 steering angle designating means 15 low pass filter means E azimuth deviation V vehicle speed δ steering angle δM steering angle target value (output of low pass filter means) φ advancing azimuth φM azimuth target value

Claims (4)

[Claims] 1. A steering instructing means for instructing an amount of change in the traveling direction of a vehicle with respect to a reference direction, a traveling direction detecting means for detecting an amount of change in the traveling direction of the vehicle, and a traveling direction change inputted from the steering instructing means. In the steering apparatus including a control unit that controls the steering mechanism such that the azimuth angle deviation between the amount of movement and the amount of change in the traveling direction of the vehicle detected by the traveling direction detection unit is zero, the control unit is the azimuth angle deviation. The steering apparatus is provided with a steering angle designating means for outputting a signal relating to the steering angle based on the above, and the steering angle designating means is configured to decrease the steering angle output with an increase in vehicle speed. 2. A steering direction instructing means for instructing an amount of change in the traveling direction of the vehicle with respect to a reference direction, a traveling direction detecting means for detecting an amount of change in the traveling direction of the vehicle, and a traveling direction change inputted from the steering instructing means. In the steering apparatus including a control unit that controls the steering mechanism such that the azimuth angle deviation between the amount of movement and the amount of change in the traveling direction of the vehicle detected by the traveling direction detection unit is zero, the control unit is the azimuth angle deviation. And a steering angle designating means for outputting a signal relating to the steering angle based on the steering angle designating means, and the steering angle designating means relates the relationship between the azimuth angle deviation and the steering angle output to the steering angle increasing rate as the azimuth angle deviation increases. The steering device is characterized in that it is set to be large. 3. The steering apparatus according to claim 1, wherein a signal relating to a steering angle from the steering angle designating means is supplied to the steering mechanism via a low pass filter means. 4. The steering apparatus according to claim 3, wherein the time constant of the low-pass filter means is changed according to the steering angle.