JPH0363085B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a parallel steering system in which the front and rear wheels are steered in the same direction when steering a working vehicle that is configured to be able to steer both the front and rear wheels. The present invention relates to a steering control device for an automated driving vehicle, which is configured to be able to freely switch between a steering type and a turning steering type in which the steering is operated in a relatively opposite direction, and is equipped with a remote control means.

[Conventional technology]

When using this type of work vehicle, such as a lawn mowing vehicle, to perform lawn mowing work by remote control,
In order to avoid leaving uncut areas, the steering is operated so that the treated work area is adjacent to the outside of the vehicle body and the vehicle sequentially travels in a straight line over the untreated work area. In steering operations such as width closing, which are performed to maneuver the vehicle so that the treated work area is adjacent to the outside of the vehicle,
Parallel steering, which allows the front and rear wheels to be steered in the same direction to correct the running direction without changing the direction of the vehicle, allows for more efficient vehicle body position correction and allows the vehicle to be steered in a way that matches the operator's sense of control. Because it was easy, the steering was controlled using parallel steering.

In working areas where the driving ground is poor, such as on slopes or uneven roads, the direction of the vehicle may change unexpectedly due to wheel slippage, etc., and the direction of the vehicle cannot be corrected using only the above-mentioned parallel steering method. There was an inconvenience that conversion could not be performed. Therefore, when correcting the vehicle orientation or changing direction, it is recommended to use a turning steering system that allows the vehicle orientation to be changed within a small turning radius by steering the front and rear wheels in relatively opposite directions. is considered.

[Problem that the invention seeks to solve]

However, in order to finely correct the orientation of the vehicle by remote control while using both the parallel steering type and the turning steering type, it is necessary to perform remote control while complicatedly switching between the two types of steering. Additionally, if the distance between the worker and the work vehicle is large or the positional relationship between the worker and the work vehicle is poor, it may be difficult to confirm the direction of the vehicle, making it difficult to operate the steering wheel. Ta.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to improve the operability of steering operation by remote control by automating the maintenance of straight running performance during steering operation using parallel steering type. It's about doing.

[Means for solving problems]

The steering control device for an automatic traveling work vehicle according to the present invention has the structure described above, and includes: an orientation detection means for detecting the orientation of the work vehicle; and an orientation control means for automatically correcting the orientation of the vehicle body; The control means automatically switches the steering operation temporarily to the turning steering type when the direction detected by the direction detecting means deviates from the reference direction by more than a certain value during remote control using the parallel steering type. A characteristic configuration is that the vehicle body orientation is automatically corrected in a direction that aligns the orientation with a reference direction.

The functions and effects of this characteristic configuration are as follows.

[Effect]

In other words, when the front and rear wheels are in a parallel steering state where they are steered in the same direction,
For example, the direction of the vehicle body at the time of starting the parallel steering type maneuver is set as the reference direction, and the direction of the vehicle body is maintained at the reference direction.In other words, even if a wheel slip occurs, the vehicle direction is automatically oriented in the direction before the slip occurred. It automatically corrects the orientation of the vehicle, much like it used to do when driving straight. Note that in a steering type for changing the orientation of the vehicle body, such as a turning steering type or a two-wheel steering type, the above-mentioned automatic correction of the vehicle body orientation is not performed.

〔Effect of the invention〕

Therefore, during remote control, the vehicle body can be quickly aligned to a predetermined steering course, and even though the vehicle can be driven with parallel steering, which is easy to steer with little meandering, the traveling direction is changed from the reference direction midway through the vehicle. Even if the vehicle deviates from the direction, the parallel steering mode is temporarily canceled and the vehicle direction is automatically corrected to maintain the reference direction using the turning steering mode.
As a result, even if the orientation of the vehicle changes unexpectedly due to wheel slipping, the operator does not have to perform steering operations to correct the orientation of the vehicle, and only needs to perform the steering operations necessary for the job. As a result, operability has improved significantly.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

As shown in FIGS. 5 and 6, a seat 2, a handle H, and a transmission case M are provided on the rear side of the fuselage frame 1 at the bottom of the vehicle body V, and an engine E is provided on the front side. Front and rear drive wheels 3F and 3R as wheels 3 are provided at the bottom, and a lawn mowing device 4 having a disc-type cutting blade inside is suspended between the front and rear wheels 3F and 3R so as to be movable up and down, thereby creating a four-wheel drive system. The lawn mowing work vehicle is configured as a type work vehicle.

As shown in FIGS. 3 and 4, the output of the engine E is transmitted to a hydraulic continuously variable transmission (HST) provided in the transmission case M.
A gear change operation is performed by a gear change pedal 9 or a motor 10 with a reduction gear as an actuator for automatic gear change, and each differential device 3a of the front and rear wheels 3F, 3R is operated.
3b, and is also transmitted to the lawn mower 4, so that the front and rear wheels 3F, 3R and the lawn mower 4 can be driven simultaneously.

To perform the gear shifting operation of the transmission device HST, the eighth
As shown in the figure, the gearshift pedal 9 is interlocked with the integrally swingable gearshift arm 11 via a push/pull rod 12, and the gearshift pedal 9 is operated by stepping from the gearshift neutral position N to the forward forward side F. The more the driver presses the pedal to the rearward side R, the more the driver can move the vehicle forward at high speed, and the more the driver presses toward the rearward side R, the more the driver can move the vehicle into a high-speed reverse state. A relay swinging arm 13 in which the motor 10 serving as an actuator for automatic speed change control is connected to the speed change arm 11 via a push/pull rod 12.
is connected using a multi-plate friction transmission mechanism D that allows operation by the speed change pedal 9,
Although the speed change operation can be performed automatically, the speed change operation can also be performed manually using the speed change pedal 9. The position of the speed change operation by the speed change pedal 9 or the motor 10 is detected by a potentiometer _R3 that is linked to the rotation of the speed change operation shaft 14 of the speed change device (HST), and is detected by the control device I.
It is designed to provide feedback to

The front and rear wheels 3F and 3R are configured so that they can be steered not only as drive wheels but also as steering wheels, and can be operated manually using the handle H, remotely controlled by radio guidance, etc.
Power steering can be operated by automatic steering control using preset control parameters.

The handle H is configured to be able to move up and down with respect to the vehicle body V, and when not needed such as during remote control or automatic steering control, it can be lowered toward the vehicle body V side to prevent it from becoming sluggish while driving. It is set as. and,
The amount of operation is detected by a potentiometer _R0 that is linked to the rotating operation of the handle H.

Further, as a means for detecting the running direction, an azimuth sensor 5 is installed which uses a geomagnetic sensor that detects the azimuth of the current running point by sensing changes in the geomagnetic field.

Incidentally, since both the front wheels 3F and the rear wheels 3R are configured to be able to be steered, by steering the front and rear wheels 3F and 3R in the same direction, the direction of the vehicle body V can be changed without changing the direction. A parallel steering type that moves the front wheels in parallel, a turning steering type that allows turning with a small turning radius by steering the front and rear wheels 3F and 3R in relatively opposite directions, and a normal steering type that allows only the front wheels 3F to be steered like a car. The two-wheel steering type is selectable.

The power steering operation for the front and rear wheels 3F and 3R will be explained below.

As shown in FIG. 3, reciprocating hydraulic cylinders 15F and 15R are provided so as to be movable in the left and right directions of the vehicle body, and are connected to the front and rear wheels 3F and 3R via steering tie rods 16.
It is configured to perform this by controlling ON/OFF of electromagnetic valves 17F and 17R that operate the hydraulic cylinders 15F and 15R. and a steering amount operated by the handle H or a steering amount by remote control;
Potentiometers as steering angle detection means provided on each of the front and rear wheels 3F and 3R
Feedback control is performed to drive the electromagnetic valves 17F and 17R so that the values detected by R ₁ and R ₂ match.

Further, the differential gear 3b for the rear wheels 3R is configured such that the differential rotation can be stopped and released by a deflock mechanism F.

As shown in FIG. 9, the differential gear mechanism F comprises a differential gear 3b supported within the transmission case M via bearings 18, 18.
A piston 21 that functions as a shift fork that slides on the differential gear shaft 20 is formed at one end side with an engaged portion 19b that engages with the engaging portion 19a of the shifter 19 to perform a deflocking action. It is supported in a biased state by a spring 23 on a bearing support case 22 formed integrally with the bearing support case 22 . Further, a hydraulic port 24 is formed in a portion of the bearing support case 22 corresponding to the sliding end of the piston 21.
The bearing support case 2 at the inlet end 24a of 4
A deflock operating solenoid valve 25 is attached to the upper end surface of the actuating device 3b, and the operation of the solenoid valve 25 controls maintenance and release of the deflocking action of the actuating device 3b.

The output signal of the orientation sensor 5 is inputted to the multiplexer 30 together with the signals from the potentiometers R ₀ to R ₃ via the bandpass filter 29 and the buffer A ₀ , and digitally converted by the A/D converter 31 . and is input to the CPU 27.

Further, in the manual mode, the parallel steering,
A steering type selection switch that selects which type of steering is to be used: turning steering or two-wheel steering.
SW ₁ and a remote control switch SW ₂ which instructs an operation mode for remote control using a transmitter 6a (not shown) based on the guidance signal received by the receiver 6b.
is provided.

As shown in FIG. 7, the transmitter 6a includes a steering lever 7 that can be operated in the front, back, left, and right directions, and a gear shift lever 8 for controlling forward and backward movement and stopping. The steering wheel is configured to switch between the parallel steering type and the turning steering type by the operation, and to control the steering amount by the left and right operations.

Then, as shown in FIG. 1, the receiver 6b
1st channel for steering type selection outputted from CH ₁ , 2nd channel for steering operation
The signals of CH ₂ and the third channel for speed change operation CH ₃ are converted into voltage signals by the F/V converter 32, and the remote control switch SW ₂ is turned on.
It is connected in the control device I via the analog switch G ₀ only when the signal is selected.

And the potentiometer during manual operation
The amount of steering operation by R ₀ or the amount of steering operation from the second channel CH ₂ by remote control is input to the drive circuits 33F, 33R of the electromagnetic valves 17F, 17R of the front and rear wheels 3F, 3R. , 3R until the detection values of the potentiometers R ₁ and R ₂ are equal to each other.
It is designed to drive 7R.

By the way, in the case of the turning steering type, the steering directions of the front and rear wheels _3F and _3R are opposite to _each other. The output of the potentiometer _R0 that detects the operation amount of the handle H based on the signal level determination result of the first channel _CH1 , or
The steering operation amount from CH ₂ is converted into an inverting amplifier.
The polarity is reversed by A ₂ and input to the electromagnetic valve drive circuit 33R on the rear wheel 3R side.

The signal of the third channel CH ₃ for shifting operation is inputted to the drive circuit 34 of the automatic shifting motor 10 via the analog switch G ₀ only when the remote control switch SW ₂ is ON, and the signal is inputted to the drive circuit 34 of the automatic shifting motor 10 to adjust the shifting position. The detected value of the detection potentiometer _R3 is the third
The transmission (HST) is driven to a position that matches the signal of channel _CH3 .

Further, the solenoid valve 25 of the deflock mechanism F selects the parallel steering type when the parallel steering type is selected by the steering type selection switch _SW1 , and when the parallel steering type is selected by the signal of the first channel _CH1 in the remote control mode. When this is selected, the solenoid valve 25 is maintained in the ON state in order to automatically stop the differential rotation of the rear wheels 3R and defrock the rear wheels 3R. Even if the steering type is other than the parallel steering type described above, if the amount of steering operation is small, the output of the potentiometer R1 for detecting the steering angle of the front wheels 3F is adjusted so that the front wheel 3F's steering angle detection potentiometer _R1 is automatically put into a deflock state. , is checked by comparators A ₁ and A ₁ having the same configuration as described above, and if the voltage is within a predetermined range, the electromagnetic valve 2 is
It is configured to output a signal that turns on 5.

In the automatic driving control by remote control, it is better to use a parallel steering type that allows parallel movement of the vehicle body V without changing the direction of the vehicle V.
Normally, steering is performed using a parallel steering type, since the meandering of the blade is reduced and uncut areas are less likely to occur. However, in steering control using only parallel steering,
If the direction of the vehicle body V changes unexpectedly, it is not possible to correct the direction of the vehicle body V. Therefore, the direction of the vehicle body V can be corrected using the turning steering method using the direction change detected by the direction sensor 5 as a control parameter. The system automatically selects the steering type and performs the steering operation so that the vehicle automatically travels while automatically maintaining straightness.

That is, as shown in the flowchart of FIG. 2, when the remote control switch SW ₂ is turned on and the remote control mode is entered, the first channel
By checking the signal change of CH ₁ , it is sensed that the steering type has been changed to the parallel steering type, and the direction sensor 5 at that time
The detected orientation Ψ is stored as the reference orientation Ψ ₀ ,
If the vehicle body V direction changes unexpectedly thereafter, the steering type is automatically switched from the parallel steering type to the turning steering type, and the vehicle body V direction is corrected so that the detected orientation Ψ matches the reference orientation Ψ ₀ . That's what I do. And this car body V
When the direction correction is completed, by automatically returning to the parallel steering type, the operator can control the vehicle so that straightness is automatically maintained by simply performing parallel steering. That is, the control device I is provided with an azimuth control means that automatically corrects the orientation of the vehicle body V so as to maintain the orientation of the work vehicle at the reference orientation Ψ ₀ , and
The azimuth control means is configured to temporarily cancel the parallel steering type and automatically correct the direction of the vehicle body V using the turning steering type when the parallel steering type is switched to remote control. It is.

In FIG. 1, A ₃ is a differential amplifier, G ₁ is the solenoid valve 25 for the defrock in manual mode and remote control mode, and the solenoid valve drive circuit 3 for front and rear wheels.
3F, 33R, and a three-state buffer for switching the control signals of the drive circuit 34 of the speed change operation motor 10 from manual operation or remote control to the CPU 27.

[Another example]

Another embodiment will be described below.

In order to automatically correct the vehicle body V direction using the above-mentioned azimuth control, the configuration is changed to a turning steering type in which the front and rear wheels 3F and 3R are steered in opposite directions, and only one of the front wheels 3F or rear wheels 3R is steered. It may also be operated.

Alternatively, while steering the front and rear wheels 3F and 3R in the same direction based on the steering operation amount from the second channel CH ₂ , based on the azimuth difference to be corrected, so that the overall steering type is parallel, , the direction of the vehicle body V may be corrected by performing a steering operation with a difference in the amount of operation of one or both of the front and rear wheels 3F, 3R.

Further, when setting the reference direction Ψ ₀ , a preset direction, for example, a reference traveling direction of the work area, may be used instead of the detected direction Ψ at the time when the steering type is switched to the parallel steering type.

Furthermore, the differential lock mechanism F may be provided not only on the rear wheel 3R but also on the front wheel 3F side.

[Brief explanation of drawings]

The drawings show an embodiment of the steering control device for an automatic traveling work vehicle according to the present invention, FIG. 1 is a circuit diagram showing the configuration of the control device, FIG. 2 is a flowchart of automatic direction correction control, and FIG. A block diagram showing the overall configuration of the control system, Fig. 4 is an explanatory diagram of the power transmission system from the engine, Fig. 5 is an overall plan view of the lawn mower, Fig. 6 is an overall side view, and Fig. 7 is a remote control system. FIG. 8 is an enlarged side view of essential parts showing the relationship between the speed change operation pedal and the automatic speed change actuator, and FIG. 9 is a partially cutaway sectional view showing the configuration of the deflock mechanism. 3F...Front wheel, 3R...Rear wheel, V...Work vehicle,
5...Direction detection means, Ψ...Detection direction, Ψ ₀ ...
Reference direction.

Claims (1)

[Scope of Claims] 1. A parallel steering type in which the front and rear wheels 3F, 3R are steered in the same direction when steering the work vehicle V configured to be able to steer both the front and rear wheels 3F, 3R; A steering control device for an automatic driving work vehicle, which is configured to be able to freely switch between a turning steering type and a turning steering type in which the steering is performed in a relatively opposite direction, and is equipped with a remote control means, the said work vehicle. Orientation detection means 5 for detecting V direction
and an azimuth control means for automatically correcting the orientation of the vehicle body, and the azimuth control means is configured such that the azimuth Ψ detected by the azimuth detection means 5 exceeds a certain value from the reference azimuth Ψ ₀ during the parallel steering type remote control. If it shifts,
An automatic system characterized by being configured to temporarily automatically switch steering operation to a turning steering type and automatically correct the vehicle body orientation in a direction that aligns the direction of the work vehicle V with a reference direction Ψ ₀ . Steering control device for traveling work vehicles.