JP2003146232A - Steering angle control system for working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering angle control system enabling easy mounting work for potentiometers. SOLUTION: A forklift using an operation lever for lateral direction control with front wheels in a traverse mode comprises a movable end operation command part 21 for changing the direction of the wheeled device to a one-end-side position in a movable range in the traverse mode, a movable end position reading part 22 for reading an output value for a lever-side potentiometer at the movable-end position, and a table making part 23 for making a correlation table for making the read output value correlate to an output value for a drive- side potentiometer corresponding to the direction control range of the traversing operation lever, previously found. During work for mounting a front-wheel-side potentiometer on a front wheel device, no troublesome work is required for making an output value for the front-wheel-side potentiometer correspond to an output value for the lever-side potentiometer.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering angle control system for a working vehicle. 2. Description of the Related Art Recently, in a working vehicle, for example, a forklift, in order to improve working performance, not only a front wheel device or a rear wheel device but also all wheel devices are steered. Some have functions. That is, this forklift is provided with a traversing mode capable of traveling in a lateral direction in addition to a normal traveling mode in which the forklift travels in a front-back direction. In contrast, fine adjustment of the traveling direction in the lateral direction is performed by the traversing operation lever. In the steering angle control of the wheel device, the steering angle, which is the direction of the wheel, is detected through a potentiometer for detecting the operation amount of the direction control cylinder device. The operation amount of the operating lever is also detected by the potentiometer,
Therefore, the values of both potentiometers must be matched. Conventionally, the operation of matching the output value of the potentiometer on the operation lever side with the output value of the potentiometer for detecting the steering angle has been performed when the potentiometer is attached to the front wheels. In the operation of attaching the potentiometer to the front wheel, the movable range of the front wheel in the traversing mode [± 22.5 degrees around a position rotated, for example, 90 degrees to the left with respect to the forward direction in the traveling mode] ( 45 degree range)]
Output value (reading value) of potentiometer at both end positions
Was mounted so as to match the output value corresponding to the same angle range on the lever-side potentiometer. More specifically, the mounting position of the potentiometer was adjusted while measuring the output value, that is, the voltage, using a tester in a state where a voltage was applied to the potentiometer by a power supply for measurement. As described above, the work of adjusting the mounting position of the potentiometer while measuring the voltage with the tester requires time and causes a mounting error. If there is an individual difference between the power supply for the vehicle and the power supply (battery) provided in the actual vehicle,
Had to be readjusted. SUMMARY OF THE INVENTION It is an object of the present invention to provide a steering angle control system for a working vehicle that can easily perform a potentiometer mounting operation and can make unnecessary extra work such as readjustment unnecessary. In order to solve the above-mentioned problems, a steering angle control system for a working vehicle according to the present invention comprises:
The vehicle has front and rear left and right wheel units, and has a traveling mode that can travel in the front and rear direction and a traversing mode that can travel in the left and right direction, and the steering angle of the front wheel device or the rear wheel device. The turning in the running mode is performed by the control, and the direction adjustment in the traversing mode in which each wheel in each of the wheel devices is turned in the lateral direction is performed by using the traversing operation means. A steering angle control system in a working vehicle that is configured to be performed by steering angle control of a rear wheel device or a front wheel device different from the wheel device that performs the direction adjustment by the traversing operation means in the traversing mode. A driven potentiometer for detecting an operation amount of a direction control cylinder device for performing a turning of a wheel device to be performed, and a driving potentiometer for detecting an operation amount of the traversing operation means. And a control device for inputting at least output values from both of the potentiometers and operating the direction control cylinder device based on output values from the drive-side potentiometers. A movable end operation command section for turning the wheel device to one end position of the traversing movable range at the time of attaching the potentiometer to the wheel device, and a movable end position for reading an output value of the driven-side potentiometer at the movable end position. A reading unit, and a table creation unit that creates a table that associates the read output value with the output value of the drive-side potentiometer corresponding to the direction adjustment range of the traversing operation unit that is determined in advance. Things. According to the configuration of this steering angle control system, the direction adjustment in the traversing mode is performed based on the correspondence table between the output values of the driven potentiometer and the driving potentiometer. When attaching to the device, the troublesome work of adjusting the output values of the potentiometers at both ends of the movable range to the output values of the drive-side potentiometer corresponding to the movable range of the traversing operation means can be eliminated. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A steering angle control system for a working vehicle according to an embodiment of the present invention will be described below with reference to FIGS. In the present embodiment, a forklift that can travel in a lateral direction in addition to ordinary traveling in a front-rear direction will be described as a working vehicle. As shown in FIG. 1, this forklift is provided with wheel devices 2 and 3 at front, rear, left and right positions of a vehicle body 1 provided with a fork portion (not shown) for holding luggage on the front surface, and also in a front-rear direction. It is possible to cope with a traveling mode of traveling and a traversing mode of traveling in a lateral direction. In the traveling mode, the directions of the wheels 4 and 5 of the left and right front and rear wheel devices 2 and 3 are basically directed in the front-rear direction, and the operation provided on the driver's cab. The left and right rear wheels 5 (5
A, 5B) are turned, and in the traversing mode, the directions of the wheels 4, 5 in the wheel devices 2, 3 are basically in the left-right direction (lateral direction); The left and right front wheels 4 are turned by a traversing operation lever (traversing operation means) provided on the driver's cab, for example, in a direction of 90 degrees to the left with respect to the direction.
The direction of (4A, 4B) can be adjusted in the same direction within a small angle range (for example, a range of ± 22.5 degrees around the horizontal direction). The gist of the present invention resides in a steering angle control system provided with a function for matching the steering angle position of the front wheel 4 with the operation position of the operation lever in such a forklift. The description will focus on the parts. As shown in FIG. 2, the steering angle control system is basically connected to the steering shafts of the left and right front wheels 4 (4A, 4B) to control the turning or the direction of the front wheels 4. The steering angle of the control cylinder device 11 (11A, 11B) and each front wheel 4 (4A, 4B) is detected by the amount of movement (movement amount) of the rod portion 11a of the direction control cylinder device 11 (11A, 11B). In order to detect the operation angle (operation amount), the front wheel-side potentiometer (driven side potentiometer) 12 (12A, 12B) interlocked (coupled) to the rod portion 11a and the operation lever 13 (linkage). Side potentiometer (drive side potentiometer) 14 for controlling
(11A, 11B), a hydraulic pump 16 for supplying a hydraulic pressure via a hydraulic pipe 15, an electric motor 17 for driving the hydraulic pump 16 to rotate, and the above-described directional control cylinder device 1
1 (11A, 11B), an electromagnetic proportional switching valve (more precisely, an electromagnetic proportional flow control valve) 18 (18A, 18B) interposed in the middle of the hydraulic pipe 15 and an operation from the operating lever 13 in the transverse mode. The angle, that is, the output value of the lever-side potentiometer 14 is input, and the amount of oil corresponding to this output value (operation angle) is set in each direction control cylinder device 11.
(11A, 11B), and a control device 19 for outputting a control command to each of the electromagnetic proportional changeover valves 17. Further, as described above, the front wheel-side potentiometer 12 is connected to the front wheel device 2. A setting function (matching function) for attachment is provided. That is, the control device 19 is provided with a potentiometer setting button 20.
As shown in FIG. 3, a movable end operation command unit 21 for turning the front wheel 2 to a movable end position in the lateral direction (for example, a position of 90 degrees + 22.5 degrees to the left in the forward direction), and the movable end operation A movable end position reading unit 22 for reading an output value (voltage value) of the front wheel potentiometer 12 when the front wheel 2 is positioned at a predetermined movable end by the command unit 21;
The two potentiometers 12 and 14 are connected to each other based on the output value read by the control unit and both output values (voltage values) of the lever-side potentiometer 14 corresponding to the direction adjustment range (both ends of the range) of the operation lever 13 input in advance. Table creation unit 23 for creating a correspondence table (also referred to as a conversion table) for the output values of the table, and a table storage unit 2 for storing the correspondence table created by the table creation unit 23
4 are provided. In the table creating section 23, as shown in FIG. 4, both potentiometers 12 and 14 are used.
The output value a actually detected when creating the correspondence table between the output values is the one end position of the movable range of the front wheel 2 of the front wheel potentiometer 12 attached to the front wheel device 2, The output value b at the other end position of the movable range is determined by calculation by adding the numerical value to the output value at the one end position since the numerical value of the movable range is determined in advance. The output values a and b at both ends of the movable range of the front wheel potentiometer 12 obtained in this way and the output values c and d at both ends of the direction adjustment range of the lever potentiometer 14 set in advance are determined. Mutual correspondence is performed. A straight line indicating this association is as shown by a solid line K in FIG. Next, the setting operation of the front wheel potentiometer in the steering angle control system will be described. The setting operation is performed by pressing a setting button 20 provided on the control device 19. When the setting button 20 is pressed, first, the movable-end operation command unit 21 causes the front wheel 4 to be moved to the electromagnetic proportional switching valve 18. An operation command for turning in the horizontal direction is output. In response to this operation command, the direction control cylinder device 1
1 is actuated to rotate the front wheel 4 laterally and to its mechanically limited movable end position (90 ° + 22.5 °). When the front wheel 4 rotates to the movable end position and a predetermined time elapses (sufficient time until the front wheel 4 rotates to the movable end position), the movable end position reading unit 22 causes the front wheel potentiometer 12 at the movable end position to read. Is read (input), and this output value is temporarily stored. Next, based on the output value a read by the table creating unit 23, the output values a and b of the front wheel potentiometer 12 at both ends of the movable range and the output values a and b of the operation lever 13 in the operation range are determined. A correspondence table (actually, data of discrete values) as shown by a straight line K in FIG. 4 that associates the output values c and d of the lever-side potentiometer 14 at the operation end position is created and stored in the table. Stored in the unit 24. In the traversing mode, when the operation lever 13 is operated and the output value from the lever-side potentiometer 14 is input, the output value is calculated based on the correspondence table stored in the table storage unit 24. The corresponding reading of the front wheel potentiometer 12 is read,
The direction control cylinder device 11 is controlled so as to have the indicated value, and the direction adjustment at the time of traversing is performed. Of course, in other operation modes, for example, in a normal traveling mode, the amount of rotation of the operation handle is input to the control device 19 and the rear wheel 5 of the rear wheel device 3 is operated.
Is turned, the vehicle body 1 is turned. Therefore, a control command is output from the control device 19 to the motor control unit 31 that controls the drive motor 17 of the hydraulic motor 16. As described above, the front-wheel-side potentiometer 12
The direction adjustment in the traversing mode is performed based on the correspondence table between the output value of the lever-side potentiometer 14 and the lever-side potentiometer 14, so that when the front-wheel-side potentiometer 12 is set, the front-wheel-side potentiometer is connected to the front-wheel device 2 When mounting on the end of the movable range, the troublesome work of adjusting the output value of the potentiometer to the output value of the lever-side potentiometer corresponding to the movable range of the operating lever is not required. However, when there is an individual difference between the power supply for measurement and the power supply of the actual vehicle, readjustment can be made unnecessary. In the above embodiment, the control device is provided with a setting button for the front-wheel-side potentiometer. However, it is needless to say that the setting button can be provided at any location.
In the above embodiment, the control device for setting the front-wheel-side potentiometer includes a movable-end operation command unit,
A movable end position read command unit, a table creation unit, and a table storage unit are provided with four components. These components are classified based on their functions.
The component may have any name as long as it has these functions. Further, in the above embodiment, the steering in the normal running mode is performed by the rear wheel device, and the direction adjustment in the traverse mode is performed by the front wheel device. The steering in the traveling mode may be performed by the front wheel device, and the direction adjustment in the traverse mode may be performed by the rear wheel device. In the above embodiment, the forklift is described as the working vehicle. However, the working vehicle is not limited to the forklift, and may be applied to other vehicles such as a luggage transporting trolley. It is. As described above, according to the configuration of the steering angle control system in the working vehicle of the present invention, the traversing mode in the traversing mode is based on the correspondence table between the output values of the driven potentiometer and the driving potentiometer. Since the direction adjustment is performed, when the driven-side potentiometer is mounted on the wheel device, which has been conventionally performed, the output value of the potentiometer at both ends of the movable range corresponds to the movable range of the traversing operation means. The troublesome work of adjusting to the output value of the drive potentiometer becomes unnecessary,
It is possible to eliminate the need for readjustment when there is an individual difference between the power supply for measurement and the power supply of the actual vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing an arrangement state of a wheel device in a forklift according to an embodiment of the present invention. FIG. 2 is a block diagram showing a schematic configuration of a steering angle control system according to the present embodiment. FIG. 3 is a block diagram showing a schematic configuration of a control device in the steering angle control system. FIG. 4 is a graph showing the contents of a table created by a table creation unit of the control device. DESCRIPTION OF SYMBOLS 1 Vehicle main body 2 Front wheel device 3 Rear wheel device 4 Front wheel 5 Rear wheel 11 Direction control cylinder device 12 Front wheel potentiometer 13 Operation lever 14 Lever potentiometer 19 Control device 20 Setting button 21 Moving end operation Command unit 22 Movable end position reading unit 23 Table creation unit 24 Table recording unit

Claims (1)

Claims: 1. A vehicle comprising a wheel device on each of front, rear, left and right sides of a vehicle body, and having a traveling mode capable of traveling in a front-rear direction and a traversing mode capable of traveling in a left-right direction. The turning in the traveling mode is performed by the rudder angle control in the side wheel device or the rear wheel device, and the direction adjustment in the traversing mode in which each wheel in each of the wheel devices is turned in the lateral direction is performed by a traversing operation. Means for controlling the steering angle of the rear wheel device or the front wheel device different from the wheel device performing the turning in the running mode by means of the steering device. A driven potentiometer for detecting an operation amount of a direction control cylinder device for turning a wheel device whose direction is adjusted by the traversing operation means, A drive-side potentiometer that detects the operation amount of the control device, and a control device that inputs the output values from at least the both potentiometers and that activates the direction control cylinder device based on the output values from the drive-side potentiometers, and A movable end operation command unit for turning the wheel device to one end position of the traversing movable range at the time of attaching the driven potentiometer to the wheel device; and a driven potentiometer at the movable end position. And a table for associating the read output value with the output value of the drive-side potentiometer corresponding to the previously determined direction adjustment range of the traversing operation means. A steering angle control system for a working vehicle, comprising: a table creating unit. .