JPH09315127A - Horizontal control method for deck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably run a deck by efficiently actuating a suspension mechanism. SOLUTION: Inclination sensors 8 and 9 detect the inclination of a deck body 1 and then calculate horizontal correction values for the distances from the deck body 1 to axles 3 for respective wheels 2. Ultrasonic sensors 7 detect heights in rugged portions on a floor F ahead of the wheels 2 for the respective wheels 2. The levels of the rods of cylinders 4 to be moved for the respective wheels 2 are obtained from the detected heights in rugged portions and horizontal correction values, on the basis of which level the cylinders 4 are driven to be raised or lowered respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for horizontally controlling a luggage carrier, in which a cylinder is provided between the luggage carrier body and each axle of a plurality of wheels so that the luggage carrier body can be moved up and down.

[0002]

2. Description of the Related Art A conventional horizontal control method for a cargo bed is disclosed, for example, in Japanese Patent Laid-Open No. 50-63618. That is, a height detection cylinder is attached to a suspension cylinder that supports the vehicle body of a self-propelled vehicle, which corresponds to a loading platform, and a height indicating cylinder that interlocks with this height detecting cylinder is provided. By connecting a switch and controlling the amount of oil flowing in and out of the suspension cylinder by a solenoid valve operated by this limit switch, and holding the suspension cylinder at an arbitrary height, the floor surface of the vehicle body can be held horizontally. There is.

An accumulator is attached to the suspension cylinder in order to improve the habitability of the self-propelled vehicle during traveling.

[0004]

However, if the horizontal control of the bed and the suspension mechanism are operated at the same time, there is a fear that neither function can be satisfied.

For example, the self-propelled vehicle makes a right turn, the left front end of the self-propelled vehicle inclines downward, and horizontal control of the luggage carrier is executed, and the suspension cylinder of the wheel located at the left front is extended to move the luggage carrier. When you try to level it against the floor,
If there is an uneven portion on the road surface in front of the wheel located at the front left, the suspension mechanism tries to contract the suspension cylinder. Therefore, neither the cargo bed horizontal control nor the suspension mechanism works, the cargo bed body is affected by the unevenness of the road surface, and the downward inclination of the left front end of the self-propelled vehicle is not recovered, resulting in unstable running. There was a fear of becoming.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a horizontal control method for a cargo bed which can effectively operate a suspension mechanism and realize stable traveling.

[0007]

In order to achieve the above-mentioned object, a horizontal control method for a luggage carrier according to the first aspect of the present invention is such that a cylinder is provided between the luggage carrier main body and each axle of a plurality of wheels, and the luggage carrier main body is A horizontal control method for a loading platform capable of raising and lowering, wherein a tilt angle of the loading platform body is detected, a horizontal correction value of a distance between the loading platform body and the axle is calculated for each wheel, and a wheel is set for each wheel. Detecting the height of the uneven portion of the road surface in front of, by the height of the uneven portion and the horizontal correction value, the movement amount of the rod of the cylinder of each wheel is obtained, and in accordance with this movement amount, each cylinder is raised, Alternatively, it is characterized by being driven downward.

Here, the inclination angle of the luggage carrier body is detected by, for example, an inclination sensor, and the height of the uneven portion on the road surface in front of the wheels is detected by an ultrasonic sensor. By the above method, the movement amount of the rods of the cylinders is obtained from the horizontal correction value for each wheel and the height of the uneven portion of the road surface in front of the wheels, and the rods of the cylinders of each wheel are driven in unison and the uneven portion of the road surface is obtained. The main body of the luggage carrier is kept horizontal without being affected by. Therefore, stable running is realized.

Further, the horizontal control method for the cargo bed of the second invention is as follows.
A horizontal control method for a cargo bed according to the first aspect of the present invention, which is characterized by determining whether the movement amount of a rod of a cylinder of each wheel is positive or negative and driving each cylinder upward or downward according to the positive or negative. is there.

According to the above method, each cylinder is driven by determining whether the movement amount of the rod of the cylinder is positive or negative, and thus a very simple control configuration can be realized.
A low-cost control method is realized.

Further, the load carrier horizontal control method of the third invention is the load carrier horizontal control method of the first invention, wherein the distance between the load carrier main body and each axle is detected, and the detected distance and wheel are detected. It is characterized in that the deviation of the movement amount of the rod of the cylinder is calculated, and each cylinder is driven up or down according to this deviation.

According to the above method, the distance between the luggage carrier main body and each axle is detected and used as a feedback value, whereby the rod position of the cylinder is accurately controlled and extremely stable traveling is realized.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a luggage carrier body of a cart using the method for horizontally controlling a luggage carrier according to the present invention, and FIG. 2 is a side view of a wheel portion thereof.

Four pairs of wheels 4 are provided on the bottom surface of the luggage carrier body 1 symmetrically in the front-rear direction and the left-right manner.
A cylinder 4 and a lift arm 5 are interposed between the axles 3, and the operation of the cylinder 4 allows the loading platform body 1 to move up and down. In addition, the support 6 protruding forward from the axle 3
An ultrasonic sensor 7 for measuring the distance from the center of the wheel 2 (axle 3) to the floor surface (road surface) F is attached to the.

Further, in the center of the upper surface of the luggage carrier body 1, a front-rear inclination sensor 8 for detecting an inclination in the front-rear direction (a forward downward angle is +), and a inclination for a left-right direction (a left downward angle is +) are detected. The horizontal inclination sensor 9 is attached. The inclination sensors 8 and 9 are, for example, Japanese Patent Publication No. 59-5348.
The tilt sensor disclosed in Publication No. 5 is used.

A control block diagram of the cylinder 4 is shown in FIG. The tilt sensors 8 and 9 and the ultrasonic sensor 7 of each wheel 2 are connected to a controller 11 provided on the luggage carrier body 1, and the controller 11 is a solenoid valve of each cylinder 4 (a solenoid valve of three ports and three positions) 12 Coils 12A, 12B
It is connected to the. When the coil 12A is excited by the controller 11, pressure oil is supplied from the pump to the cylinder 4, the rod 4A is pushed, the position of the bed main body 1 of this wheel portion is raised, and the coil 12B is excited by the controller 11. Then, the pressure oil flows out from the cylinder 4 to the tank, the rod 4A contracts, and the luggage carrier body 1 of this wheel portion descends.
When neither of the coils 12A and 12B is excited, the pressure oil in the cylinder 4 is retained and the height is maintained at present.

The configuration of the controller 11 will be described with reference to the block diagrams of FIGS. 4 and 5. Based on the tilt angle θ detected by the front-rear tilt sensor 8, as shown in FIG. 6, the calculator 21 and the inverter 21A for calculating the horizontal correction values A and B of the front and rear wheels 2 by the formula (1) are provided. Similarly, a calculator 22 and a reverser 22A for calculating the horizontal correction values C and D of the left and right wheels 2 according to the equation (2) based on the tilt angle β detected by the left and right tilt sensor 9 are provided. However, in the formula (1), a is the distance in the front-rear direction between the front-rear tilt sensor 8 and each of the front and rear wheels, and in formula (2), x is the distance in the left-right direction between the left-right tilt sensor 8 and each of the left and right wheels. is there.

Front wheels; A = atan θ Rear wheels; B = −atan θ (1) Left wheels; C = xtan β Right wheels; D = −xtan β (2) Ultrasonic sensor 8 detected by ultrasonic sensor 8
The distance δ between the tip of the vehicle and the floor surface is delayed by the time required for the body 1 to move between the wheel 2 and the ultrasonic sensor 1.
A next-delay circuit 23 is provided, and a subtractor 24 is provided to find the difference between the delayed distance δ and the radius r of the wheel 2, that is, the height h of the uneven portion 10 of the floor surface F shown in FIG.

Further, for each wheel 2, an adder 25 for adding horizontal correction values A, B, C, D according to the front-rear and left-right positions of the wheel 2, and a height h of the uneven portion 10 are subtracted from the adder 25. The subtracter 26 for obtaining the movement amount J of 4A and the comparison for outputting the raising command, that is, the excitation signal of the coil 12A, are determined if the movement amount J of the rod 4A is larger than a predetermined value α (> 0). vessel
27 and a comparator 28 for judging whether the movement amount J of the rod 4A is smaller than a predetermined value −α, and if it is smaller, outputting a down command, that is, an excitation signal of the coil 12B. In addition,
The moving amount J of the rod 4A is smaller than α (> 0), and-
When it is larger than α, no excitation signal is output and the position of the rod 4A is held.

The operation of the above structure will be described below.
Now, the cart body 1 is rotated by the cart turning to the right or by an unbalanced load.
Is inclined diagonally forward to the left, and there is an uneven portion 10 on the floor surface A in front of the wheel 2 located on the front left side.

At this time, the inclination angles θ and β detected by the inclination sensors 8 and 9 are θ> 0 and β> 0, so that the horizontal correction values are A> 0, B <0, C> 0 and D <. Becomes 0,
The movement amount J of the rod 4A of the cylinder 4 of the wheel 2 located on the left front is plus, that is, the raising direction, the wheel 2 located on the rear right.
The moving amount J of the rod 4A of the cylinder 4 is minus, that is, the lowering direction, the moving amount J of the rod 4A of the cylinder 4 of each wheel 2 located on the front right and the rear left is determined by the difference between the horizontal correction values. Rod of cylinder 4 of each wheel 2 all at once
4A is driven and controlled so that the loading platform body 1 is horizontal to the floor surface F.

In the case of the wheel 2 located on the front left side, when the ultrasonic sensor 7 detects the uneven portion 10, the height h of the uneven portion 10 is subtracted from the added value of the horizontal correction values, and the rod 4A
The direction of which is determined by the difference in the horizontal correction values.
The influence of the uneven portion 10 on the is absorbed.

As described above, the horizontal correction value and the height h of the uneven portion 10 determine whether the rod 4A is to be lifted or lowered, that is, the lift of the load carrier main body 1 on each wheel 2 is effective. It is possible to realize stable running even when turning or when an unbalanced load is applied. Also, the conventional accumulator can be eliminated.
Further, by driving the cylinder 4 by judging whether the movement amount J of the rod 4A of the cylinder 4 of each wheel 2 is positive or negative, an extremely simple control configuration including the controller 11 can be realized, and stable traveling at low cost can be achieved. Can be realized.

In the present embodiment, the positive / negative of the moving amount J of the rod is judged by the comparators 27 and 28 to output the raising command and the lowering command. However, the axle 3 and the luggage carrier body 1 (bottom surface). The distance between them is detected by a distance sensor (for example, a differential transformer), the deviation J is taken as a target value of the movement amount J of the rod and the value of the distance sensor as a feedback value, and the solenoid valve 12 is driven by this deviation. You can also
At this time, the position of the rod 4A of the cylinder 4 can be accurately controlled, and extremely stable running can be realized.

Further, in the present embodiment, the ultrasonic sensor 7 is used for detecting the height of the uneven portion 10, but it is also possible to detect it by a measuring instrument using light.

[0026]

As described above, according to the first aspect of the present invention,
The movement amount of the cylinder is obtained from the horizontal correction value for each wheel and the height of the uneven portion on the road surface in front of the wheel.By driving the cylinder, both the bed horizontal control and the suspension function can be effectively operated. It is possible to realize stable traveling even when turning or when an unbalanced load is applied.

Further, according to the second aspect of the present invention, the cylinder is driven by determining whether the movement amount of the rod of the cylinder of each wheel is positive or negative, so that an extremely simple control configuration can be realized, which is stable at low cost. Driving can be realized.

Further, according to the third aspect of the present invention, by detecting the distance between the luggage carrier body and each axle and using it as the feedback value, the rod position of the cylinder can be accurately controlled, and extremely stable traveling can be realized. You can

[Brief description of drawings]

FIG. 1 is a perspective view of a luggage carrier main body of a cart using the method for horizontally controlling a luggage carrier according to the present invention.

FIG. 2 is a side view of a wheel portion of a luggage carrier body of the same cart.

FIG. 3 is a horizontal control configuration diagram of a luggage carrier body of the same cart.

FIG. 4 is a block diagram of a controller of a luggage carrier body of the same cart.

FIG. 5 is a block diagram of a controller of a luggage carrier body of the same cart.

FIG. 6 is an explanatory diagram of horizontal control of a luggage carrier body of the same cart.

[Explanation of symbols]

 1 Body 2 Wheels 3 Axle 4 Cylinder 4A Rod 5 Lift arm 6 Support 7 Ultrasonic sensor 8, 9 Inclination sensor 10 Concavo-convex part 11 Controller 12 Solenoid valve F Floor (road surface)

Claims (3)

[Claims] 1. A horizontal control method for a luggage carrier, wherein a cylinder is interposed between the luggage carrier body and each axle of a plurality of wheels, and the luggage carrier body can be raised and lowered. For each wheel, calculate the horizontal correction value of the distance between the luggage carrier body and the axle, and detect the height of the uneven portion of the road surface in front of the wheel for each wheel,
From the height of the uneven portion and the horizontal correction value, the movement amount of the rod of the cylinder of each wheel is obtained, and according to the movement amount,
A horizontal control method for a cargo bed, characterized by driving each cylinder up or down. 2. The horizontal control method for a cargo bed according to claim 1, wherein the positive or negative of the movement amount of the rod of the cylinder of each wheel is determined, and each cylinder is driven upward or downward. Characterize. 3. The horizontal control method for a luggage carrier according to claim 1, wherein the distance between the luggage carrier main body and each axle is detected, and the deviation between the detected distance and the movement amount of the rod of the wheel cylinder is calculated. ,
It is characterized in that each cylinder is driven up or down according to this deviation.