JP2651667B2 - Steering system for automatically traveling vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering system for an automatically traveling vehicle, and more particularly to a steering system for an automatically traveling vehicle that can switch between automatic steering and manual steering.

[0002]

2. Description of the Related Art In recent years, various techniques have been studied for automatically driving vehicles such as automobiles and transport vehicles.
For example, some guided automatic traveling vehicles that travel along a required course have already been put into practical use. An unguided unmanned vehicle that can travel autonomously while recognizing its own position by giving course information to the control system has also been proposed. Guided or non-guided autonomous vehicles have been developed on the premise that humans do not ride as pilots, so many of them do not have steering handles, but they are used for emergency steering. There is also a handle provided. Steering devices capable of performing automatic steering and manual steering using a steering wheel include the following (i). (I) separating the steering axis into an upper steering axis and a lower steering axis;
When operating the steering device by transmitting the rotation of the handle attached to the upper steering shaft to the lower steering shaft via the engagement / disengagement switching means, the rotation of the steering servomotor is stopped, and the rotation of the steering servomotor is paired with the chain. Vehicle steering in which the rotation of the steering servomotor is not transmitted to the upper steering shaft by switching the engagement / disengagement switching means when operating the steering device by transmitting the transmission to the lower steering shaft via a transmission mechanism comprising Apparatus (for example, Japanese Utility Model Publication No. 58-4759).

[0003]

Among the conventional guided or non-guided vehicles that do not have a steering wheel, those that do not have a steering wheel require an operation for returning to the correct course when the vehicle has gone off the course. There are drawbacks that are cumbersome. 2. Description of the Related Art Some vehicles and the like equipped with a conventional automatic steering device are provided with a steering handle. However, if the handle shaft turned by the handle and the output shaft of the turning drive means of the autopilot are not alternatively connectable to the steering shaft, the handle may rotate during the autopilot, However, there is a disadvantage that it becomes complicated. For example, it is conceivable that automatic driving can be performed in an electrically driven electric vehicle or the like used in a golf course, and if it is possible to switch between automatic driving and manual driving so that a human can ride even during automatic driving, it is very possible. It becomes convenient. In this case, when an output shaft such as a motor of a turning drive unit is connected to the steering shaft and a handle shaft turned by the handle is connected to the steering shaft, a phenomenon in which the steering wheel rotates during automatic steering cannot be avoided. For this reason, when the occupant is gripped by the steering wheel during automatic driving, the arm must be moved together with the movement of the steering wheel, and there is a drawback that the riding comfort is deteriorated. According to the steering device of the above (i), the steering wheel does not rotate during automatic steering, but it is necessary to provide complicated engagement / disengagement switching means for vertically moving the upper steering shaft at the time of switching.
In addition, a chain is mounted on a chain wheel attached to the output shaft of the steering servomotor and a chain wheel attached to the lower steering shaft, so that the rotation of the steering servomotor can be transmitted to the lower steering shaft to operate the steering device. This disadvantageously complicates the device and increases the occupied space. The problem to be solved by the present invention is to provide a steering device for an automatically traveling vehicle that does not have the above-mentioned disadvantages of the prior art, in other words, switching between automatic steering and manual steering is easy, and It is an object of the present invention to provide a compact steering apparatus for a self-running vehicle that is simple and has no structure.

[0004]

The present invention employs the following structure as means for solving the above-mentioned problems. The configuration of the present invention controls at least one wheel steered by turning the steering shaft, turning drive means for turning the steering shaft, rotation driving means for rotating the wheels, turning driving means, and rotation driving means. In a self-driving vehicle equipped with a control device, a handle shaft extending in a vertical direction is supported by a member provided on a vehicle body frame so that the handle shaft can be rotated by the handle, and a turning drive means includes a steering motor and a speed reducer. The rotation shaft of the steering motor, the input shaft and the output shaft of the speed reducer are arranged and connected so as to be located on the same axis extending vertically, and the housing of the speed reducer is supported by a support member provided on the body frame. A steering motor fixed to an upper side of a housing of a speed reducer, rotatably supported and connected to the support member via a first switching means so as to be detachable; The connected portion is detachably connected to a steering shaft disposed below the speed reducer or a portion connected to the steering shaft via the second switching means, and a portion separated from the rotation axis of the housing and a handle shaft. When the handle shaft is turned by operating the handle with the first switching means in the disengaged state and the second switching means in the connected state, the handle shaft is rotated. Is transmitted to the steering shaft via the link, the housing of the speed reducer and the second switching means, and the first switching means is connected and the second switching means is disengaged to rotate the steering motor. The rotation of the vehicle is transmitted to a steering shaft via a speed reducer. As the turning drive means, for example, a step motor is used, but the present invention is not limited to this.

[0005]

According to the steering apparatus for an automatically traveling vehicle of the present invention, when it is desired to perform automatic steering by the turning drive means, the first switching means is connected and the second switching means is disengaged, thereby enabling steering. When the rotation of the motor is decelerated by the speed reducer and transmitted to the steering shaft, and when it is desired to perform manual steering using the steering wheel, the first switching means is disengaged and the second switching means is engaged so that the steering wheel is engaged. The rotation of the handle shaft by the operation of the link, the housing of the reduction gear and the second
The information is transmitted to the steering shaft via the switching means. During automatic steering by the turning drive unit, the connection between the housing of the reduction gear and the steering shaft is disconnected by setting the second switching unit to the disengaged state, and the first switching unit is set to the coupled state by setting the first switching unit to the connected state. Since the housing cannot be rotated, the steering wheel does not rotate with the steering shaft, and a person can ride with confidence.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiment is an example in which the invention of this application is applied to a steering device for a vehicle that travels automatically. In this embodiment, a description will be given of an unmanned, three-wheeled vehicle which is driven by one steering wheel and is not steered and has two front wheels which are steered by a steering shaft shown in FIG. 1. The vehicle may be a two-wheeled, unmanned, self-running vehicle with two unsteered rear wheels. The body frame 1 is formed of, for example, a pipe frame made of a steel pipe, and an upper frame 1a extending upward in an inverted L-shape is coupled to a rear end thereof. A head pipe 3 is provided at a front end of the vehicle body frame 1, a steering shaft 4 is rotatably supported by the head pipe 3, and a front wheel 2 is mounted below the steering shaft 4. A pair of axles connected via a differential mechanism 6 are provided at the rear of the body frame 1, and rear wheels 5 are attached to outer ends of these axles.
a, 5b are attached, and the rear wheels 5a, 5b are rotated by a traveling drive motor 7 mounted on the rear portion of the body frame 1. The rotation of the motor 7 is transmitted to the differential mechanism 6 after being reduced by a speed reducer including gears, chains 8a, 8b, and the like.

At the rear end of the body frame 1, a step 9 for a person to ride is fixed. A turning drive means for turning and driving the steering shaft 4 is attached to a holder 10 constituting a support member provided at a front end of the body frame 1, and the turning drive means is constituted by a speed reducer 12 having a steering motor 11 mounted on an upper side. The output shaft of the speed reducer 12 is connected to the upper end of the steering shaft 4 via a coupling 32. The handle shaft 14 is connected to the housing 12a of the speed reducer 12 by the link 13
And either the rotation of the output shaft of the reduction gear 12 or the rotation of the handle shaft 14 is connected to the steering shaft 4.
It is transmitted to. Moreover, when transmitting the rotation of the motor 11 to the steering shaft 4,
When transmitting the rotation of the handle shaft 14 to the steering shaft 4 at a reduced speed by a factor of one, the rotation is transmitted as 1: 1. The handle shaft 14 is rotatably supported by a support portion 15a provided on the body frame 1 and a support portion 15b fixed to the upper frame 1a.
4a is fixed.

In this embodiment, a pair of rotary encoders 20a and 20b are used to separately detect the rotational speeds of the rear wheels 5a and 5b attached to the left and right axles connected via the differential mechanism 6, respectively. The rotation of the axle corresponding to each rear wheel 5a, 5b is provided to the encoder 20 via a chain or the like.
a, 20b. A battery 21 as a power supply unit such as the traveling drive motor 7 and the steering motor 11 is mounted on the bottom of the vehicle and almost at the center of the body frame 1. Encoders 20a and 20b are provided below the steering wheel 14a at the center of the vehicle. The traveling drive motor 7 and the steering motor 11 are controlled in accordance with the preset course information while calculating the traveling distance and the azimuth from the rotational speeds of the left and right rear wheels 5a and 5b detected at the time and constantly recognizing the own position. A computer box 16 is mounted. In this embodiment, three laser projectors 23a to 23c are provided at the front end of the upper frame 1a formed so as to protrude forward from the handle 14a, and a pair of laser projectors 23a for position checking is provided. , 23b emit a laser beam in a direction orthogonal to the center line of each vehicle, that is, right beside the vehicle, and can scan up and down. Other auxiliary laser emitter / receiver 2
3c is provided only on one side (for example, left side) of the vehicle, and emits a laser beam diagonally forward of the vehicle and can scan up and down.

The laser beams emitted from the laser projectors 23a to 23c are reflected by a reflector RFi called a corner cube disposed at appropriate intervals along both sides of the traveling course of the vehicle. Since this corner cube has a characteristic of reflecting incident light in the same direction as the incident direction, the reflected laser beam reaches the laser projectors 23a to 23c which emitted the laser beam and is detected. Thereby, the self-position of the vehicle can be checked. In addition, since one side (left side in the embodiment) of the vehicle is provided with two laser emitters and receivers, which are directed sideways and obliquely forward, the distance from the corner cube on the left side of the course can be reduced by a kind of triangulation. You can now know. In the vehicle shown in FIG. 1, an input operation device 27 for setting course information from the outside is attached to a position rearward of the upper handle 14a of the upper frame 1a. A storage device for storing the course information and the like is provided in the computer box 16.
Inside, along with a computer. The encoder 2 is positioned above the differential mechanism 6 below the input operation device 27.
Counter for counting pulse signals from 0a and 20b, i
A control box 18 containing an / o interface circuit and the like is provided. Further, the input operation device 27
A key 19 for turning on and off a main switch for turning on a power supply is attached to a lower portion of the key.

FIGS. 2 and 3 show switching means for switching between automatic steering and manual steering, that is, an apparatus for switchingly connecting one of the steering motor 11 and the handle shaft 14 to the steering shaft 4. The specific structure is shown. A holder 10 fixed to the front end of the body frame 1 includes a speed reducer 1
The second housing 12a is rotatably supported, and the steering motor 11 is arranged such that its rotating shaft 11a, the input shaft 12b of the speed reducer 12, and its output shaft 12c are located on the same axis extending in the vertical direction. Housing 1 of reduction gear 12
It is fixed to the upper end of 2a and can rotate integrally with the housing 12a. An input shaft 12b of the speed reducer 12 is coupled to a rotation shaft 11a of the steering motor 11 via a cylindrical coupling 31, and a coupling 32 is similarly connected to an output shaft 12c projecting from a lower end of the speed reducer 12. The steering shaft 4 is connected to the steering shaft 4. A flange 12d is formed on the housing 12a of the speed reducer 12, and bolts (hereinafter referred to as "el balls") 33 having a pair of spherical heads are provided on the lower surface of the flange 12d at positions 180 ° apart. And a pair of el balls 34, 34 are also fixed at positions 180 ° apart from each other on the lower surface of the plate 14b fixed to the handle shaft 14, and both ends of the links 13, 13 are connected to the respective el balls 33, 33, 34. , 34 are rotatably connected to the spherical heads. Therefore, handle shaft 1
When the rotating mechanism 4 is rotated, the entire reduction gear 12 including the housing 12a is rotated by the same angle in the same direction as the handle shaft 14 via the pair of links 13 and 13. And the speed reducer 12
The steering shaft 4 is connected to the handle shaft 14 in a 1; 1 relationship because the steering shaft 4 is connected to the output shaft 12c.

An engaging recess 12 is formed on the outer periphery of the housing 12a.
e is formed, and a through hole 40a is formed in the block 40 fixed to the holder 10 corresponding to the engaging concave portion 12e, and the first lock pin 35 is inserted into the through hole 40a. The first lock pin 35 is moved by the operation of the solenoid 36.
Is engaged with the engagement recess 12e, the rotation of the housing 12a is prevented, and the rotation of the handle shaft 14 is also prevented. An engaging recess 12e formed in the housing 12a, a through hole 40a formed in the block 40 fixed to the holder (support member) 10, and the through hole 40a
The first lock pin 35, which is inserted into the motor and moved by the operation of the solenoid 36, constitutes a first switching means. An engagement recess 32a is formed in the coupling 32 connecting the output shaft 12c of the speed reducer 12 and the steering shaft 4, and the housing 12a of the speed reducer 12 corresponds to the engagement recess 32a.
When the second lock pin 37 is inserted into the through hole 41a and the second lock pin 37 is moved by the operation of the solenoid 38 to be engaged with the engagement recess 32a. The rotation of the housing 12a can be transmitted to the steering shaft 4 via the coupling 32, provided that the first lock pin 35 is disengaged from the engagement recess 12e. An engagement recess 32 a formed in the coupling 32 connected to the steering shaft 4,
A second switching means is constituted by a through hole 41a formed in a block 41 integral with the housing 12a and a second lock pin 37 inserted into the through hole 41a and moved by the operation of the solenoid 38. Therefore, when the first lock pin 35 is removed, that is, the first switching means is disengaged, and the second lock pin 37 is fitted, that is, the second switching means is connected, the handle 14a is operated. Then, the turning force is transmitted in the order of the handle shaft 14 → the link 13 → the housing 12a → the coupling 32 to rotate the steering shaft 4.

When the first lock pin 35 is engaged, that is, the first switching means is connected, and the second lock pin 37 is removed, ie, the second switching means is disengaged, the housing 12a The rotation of the coupling 32 is prevented, and the rotation of the coupling 32 becomes free.
Is rotated, the rotational force of the rotating shaft 11a of the motor 11 is transmitted to the input shaft 12b of the speed reducer 12, the rotation of which is reduced to 1/30, and the rotation is reduced by the output shaft 12c via the coupling 32. The information is transmitted to the steering shaft 4. At this time, the rotation of the handle shaft 14 is prevented. Since there is only one engaging recess 12e, the handle 14a
Is fixed at the center position. In other words, handle 1
If the first lock pin 3 is not in a state where the first lock pin
5 is fitted into the engagement recess 12e so that the handle shaft 14 cannot be locked. In addition,
In the above embodiment, the lock pins 35 and 37 are connected to the solenoid 3
Although it is operated at 6, 38, it can be configured to be operated manually. In this embodiment, a stepping motor is used as the steering motor 11 instead of the servomotor, and the steering motor 11 is controlled in an open-loop manner.

FIG. 4 shows an example of a control circuit for the steering system. The computer CUP is connected to a motor controller MTC for controlling the drive of the step motor 11 via a parallel i / o controller PIC. When one pulse is input, the motor controller MTC supplies an excitation signal for rotating the motor by one step in the designated direction to the step motor 11. Further, a timer controller PMC is provided to enable control of the interval (cycle) of the pulse supplied to the step motor 11. The parallel i / o controller PIC, motor controller MTC, timer controller PMC and the like are provided in a controller box 18 in FIG. 1 showing a mechanical configuration of the vehicle.

Next, an example of a specific control procedure of the step motor 11 by the computer CUP will be described. When the computer CPU knows that the steering condition has been established from the course information and the information indicating the current position of the vehicle,
First, an appropriate steering direction and steering speed are obtained (step). Next, since the speed of the step motor 11 is determined by the interval (cycle) of the drive pulse, cycle value data for setting an appropriate speed is set in the timer controller PMC (step). Then, the timer controller PMC performs a timing operation based on the cycle value, and sends an interrupt signal to the computer when the set time has elapsed (step). When the timer interrupt signal is input, the computer sends binary data indicating normal rotation or reverse rotation to the parallel i / o controller PIC. At the same time, the computer counts and stores "+1" for normal rotation and "-1" for reverse rotation in order to recognize that the forward / reverse rotation signal has been sent (step). Then, returning to the step again, the steering direction and the speed are obtained based on the cycle data thus far, and the steps from the step are repeated.

Next, the step motor 1 is sent from the computer.
For example, an example of a method of determining a steering speed when outputting a steering command, that is, a cycle of a drive pulse of a step motor will be described. When driving a step motor for steering, if the angular velocity of the steering shaft is suddenly greatly changed,
The tires of the wheels of the vehicle that travels automatically cause slip on the running surface (ground). Therefore, in this embodiment, when the current steering position is set to "0" and then the steering shaft is turned clockwise or counterclockwise, respectively, as shown in FIG. When starting the steering toward, first, gradually increase the angular velocity, move from a certain point to constant velocity, and finally, gradually decrease the angular velocity and perform control to reach the target steering angle. It is supposed to do it. Specifically, as shown in Table 1 below, the angular velocity can be reduced by increasing the period of the pulse, and the angular velocity can be increased by shortening the period.

[Table 1] Further, in the example of Table 1, the rate of change of the angular velocity is initially increased during acceleration, and the rate of change is increased at the end during deceleration, without setting the cycle at equal intervals.

Further, when the steering shaft is to be turned in the opposite direction while turning, as shown in FIG. 5 (B), the steering shaft is once decelerated and then turned in the opposite direction. Gradually increase the angular velocity, go to constant velocity, and then
Control to gradually reduce the angular velocity may be performed. By controlling the step motor as described above, a smooth steering operation that does not cause tire slip can be realized as in the case of using the servo motor. According to this embodiment, unlike the case of using a servomotor, there is no need to provide an encoder or the like for detecting the number of revolutions for applying feedback in the turning drive means, and the turning drive means (steering motor ) Can be performed.

[0017]

According to the present invention, the following effects (a) and (b) are obtained by providing the structure described in the claims. (A) A steering apparatus for an automatically traveling vehicle according to the present invention is supported by a member provided on a body frame so that a handle shaft extending in a vertical direction can be rotated by a handle, and a turning drive means includes a steering motor and a speed reducer. The rotation shaft of the steering motor, the input shaft and the output shaft of the speed reducer are arranged and connected so as to be located on the same axis extending vertically, and the housing of the speed reducer is provided on the body frame. The steering motor is fixed to the upper side of the reduction gear housing, and is rotatably supported by the member and connected to the support member via the first switching means. A steering shaft disposed below the speed reducer or a portion connected to the steering shaft via the second switching means is detachably connected to the steering shaft and a portion separated from the rotation axis of the housing and a rotation axis of the handle shaft. When the first switching means is disengaged and the second switching means is coupled and the handle is operated to rotate the handle shaft, the rotation of the handle shaft is changed to the link, the speed reducer. Is transmitted to the steering shaft via the housing and the second switching means, and the first switching means is connected and the second switching means is disengaged to rotate the steering motor. , The automatic steering by the turning drive means and the manual steering by the steering wheel can be performed. Further, in the steering apparatus for an automatically traveling vehicle according to the present invention, the connection between the housing of the reduction gear and the steering shaft is cut off by the second switching means being disengaged during automatic steering by the turning drive means, and Since the housing cannot be turned by the switching means 1 being in the coupled state, the steering wheel does not rotate with the steering shaft, and a person can ride with confidence. (B) In the steering apparatus for an automatically traveling vehicle according to the present invention, the turning drive means includes a steering motor and a reduction gear, and the rotation axis of the steering motor, the input shaft of the reduction gear, and the output shaft of the reduction gear are vertically moved. Are arranged and connected so as to be located on the same axis extending in the direction, the housing of the speed reducer is supported by a support member provided on the vehicle body frame, the steering motor is fixed to the upper side of the speed reducer, and the lower side of the speed reducer Is equipped with a steering axis,
The space occupied by the steering motor, the speed reducer, these support members, the steering shaft, and the like that constitute the turning drive means of the steering device can be reduced, and these can be compactly assembled. (C) In the steering apparatus for an automatically traveling vehicle according to the present invention, the housing of the speed reducer is rotatably supported by a support member provided on the vehicle body frame and is detachably connected to the support member via the first switching means. The steering motor is fixed to the upper side of the speed reducer, and the portion connected to the housing of the speed reducer is connected to the steering shaft arranged below the speed reducer via the second switching means or a member connected thereto. Since the part separated from the rotation axis of the housing and the part separated from the rotation axis of the handle shaft are connected via a link so as to be detachable,
The structure of the transmission means for transmitting the rotation of the handle shaft to the steering shaft via the housing of the speed reducer, which constitutes a part of the turning drive means, is simplified, and the steering device itself can be made compact.

[Brief description of the drawings]

FIG. 1 is a side view showing a configuration of an automatically traveling vehicle according to an embodiment.

FIG. 2 is a side view in which a part of the steering device of the automatically traveling vehicle according to the embodiment is cut longitudinally.

FIG. 3 is a front view of a main part of the steering apparatus for an automatically traveling vehicle according to the embodiment, which is longitudinally cut through the main part;

FIG. 4 is a block diagram illustrating a configuration of a steering device for an automatically traveling vehicle according to the embodiment.

5A and 5B are diagrams showing a relationship between a target steering angle and an angular velocity according to the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body frame 2 Front wheel 4 Steering shaft 5a, 5b Rear wheel 7 Traveling drive motor 10 Holder 11 Steering motor 12 Reduction gear 12a Housing 12e, 32a Engagement recess 13 Link 14 Handle shaft 14a Handle 16 Computer box 32 Coupling 35 First 1 lock pin 36, 38 solenoid 37 second lock pin 40, 41 block 40a, 41a through hole

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Showa 61-59163 (JP, U) Japanese Utility Model Showa 60-157474 (JP, U) Japanese Utility Model Showa 58-4759 (JP, Y2)

Claims (1)

(57) [Claims] At least one wheel steered by turning a steering shaft, turning driving means for turning a steering shaft, rotation driving means for rotating wheels, control for controlling the turning driving means and the rotation driving means. In a self-propelled vehicle provided with a device, a handle shaft extending in a vertical direction is supported by a member provided on a vehicle body frame so that the handle shaft can be rotated by the handle, and a turning drive unit includes a steering motor and a speed reducer. The rotating shaft of the steering motor, the input shaft and the output shaft of the speed reducer are arranged and connected so as to be located on the same axis extending vertically, and the housing of the speed reducer is rotated by a support member provided on the body frame. A steering motor is movably supported and is detachably connected to the support member via a first switching means, and a steering motor is fixed to an upper side of a housing of the speed reducer and is connected to the housing. The separated portion is detachably connected to the steering shaft disposed below the speed reducer or a portion connected to the steering shaft via the second switching means, and the portion of the handle shaft that is separated from the rotation axis of the housing and the steering shaft. A portion separated from the rotation axis is connected via a link, the first switch is disengaged and the second switch is connected, and the handle is operated to rotate the handle. The signal is transmitted to the steering shaft via the link, the housing of the speed reducer and the second switching means, and when the first switching means is connected and the second switching means is disengaged to rotate the steering motor, the steering motor is rotated. A steering device for an automatically traveling vehicle, wherein the rotation is transmitted to a steering shaft via a speed reducer.