JPH082900A - Regulation control method for boom in vehicle for high lift work, etc. - Google Patents

Abstract

PURPOSE:To adopt an open loop control method as a regulation control method for a boom, which is not influenced by a failure of a sensor because a detection signal of the sensor is not used, and to simplify system configuration so as to improve reliability as safety control technology to that extent. CONSTITUTION:If a boom reaches a regulation line La for marking an allowable range and further the operation is conducted beyond the allowable range, a control method for an oil pressure circuit of an expansion cylinder is switched to an open loop control method, a flow rate to the expansion cylinder matching the lowering operation is computed according to the preset flow relational expression between both cylinders, and the oil pressure circuit of the expansion cylinder is controlled, according to the computed result, whereby the tip part of the boom is controlled to operate along a correction line Lb inside the regulation line La.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boom safety control technique used in aerial work vehicles, cranes and the like. More specifically, when an operation command is issued to the boom that exceeds a preset allowable range based on the overturning moment, etc., in order to improve the safety of the boom by correcting the operation within the allowable range. Regulation control method.

[0002]

2. Description of the Related Art Conventionally, in the operation control of a boom of this kind, from the viewpoint of ensuring safety, a regulation range for allowing the movement of the boom trajectory has been set in advance, and the boom exceeds the allowable range. If an operation command is issued,
There is known a safety control technology in which the operation command is corrected to stop the extension operation of the boom or add a contraction operation corresponding to the inward movement so as to automatically control it so that it is within an allowable range ( Japanese Patent Publication No. 4-19159). As a control method in this conventional technique, a closed loop control method has been adopted in which the boom posture is calculated at any time based on the detection signal from each sensor, and re-correction processing is repeated along with the operation regulation line while applying feedback. . For this reason, the control system becomes complicated, and the regulatory control process is directly affected by a sensor failure, erroneous detection, or the like, which is a problem in terms of reliability as a safety control technique.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a system configuration relating to correction control for correcting an operation command within an allowable range. The point is to provide a method for controlling boom control in aerial work vehicles that promotes simplification and improves reliability as a safety control technology that is not affected by sensor failures and the like.

[0004]

According to the present invention, in the operation control of a boom in which the attitude is controlled via a hoisting cylinder and a telescopic cylinder, the boom reaches a regulation line that defines a preset allowable range, and the boom is further permitted. When the operation outside the range is performed, the control system for the hydraulic circuits of the undulating cylinder and the telescopic cylinder is switched to the open loop control system, and the flow rate of the telescopic cylinder corresponding to the basting operation is preset. Calculated based on the flow rate relational expression between the two cylinders, and controlling the hydraulic circuit of the telescopic cylinder based on the calculation result, the tip of the boom is within the allowable range according to the tilting operation. It is characterized in that it is controlled so as to operate along a predetermined correction line.

[0005]

According to the present invention, in boom operation control,
When the boom reaches the regulation line that defines the preset allowable range and is operated outside the allowable range, the control method for the hydraulic circuit of the telescopic cylinder is switched to the open loop control method, and the boom The contraction motion is added in correspondence with the tilt motion so that the tip moves along the preset correction line within the allowable range. That is, the flow rate for the expansion / contraction cylinder corresponding to the tilting operation is calculated based on the preset flow rate relational expression, and the boom is allowed by controlling the flow rate of the hydraulic circuit for the expansion / contraction cylinder based on the calculation result. It will be controlled along a predetermined trajectory within the range. As described above, since the boom regulation control according to the present invention adopts the open loop control method that does not use the detection signal of the sensor, it is not affected by the failure of the sensor and the system configuration is simplified. To that extent, the reliability as safety control technology is improved. In addition, if there is an operation command in the allowable direction,
At that point, the system is switched to the original closed-loop control method to shift to normal operation control.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram when the present invention is applied to an aerial work vehicle. In the figure, reference numeral 1 denotes a vehicle body of an aerial work vehicle, and a revolving structure 2 is horizontally rotatably installed on the vehicle body 1 so that it can be revolved by a revolving motor described later. A boom 3 is supported on the revolving structure 2 so as to be vertically rotatable around a support shaft 4, and is configured so that it can be hoisted by a hoisting cylinder 5. further,
The boom 3 is configured to be capable of expanding and contracting in the axial direction by an expanding and contracting cylinder 6, and a bucket 7 for work is attached to the tip end thereof.
Is installed. In the figure, 8 is an operation panel.

FIG. 2 is an explanatory diagram regarding the operation restriction of the boom 3. In the figure, La is a regulation line, which is preset in order to regulate the operation of the boom 3 within an allowable range from the viewpoint of ensuring safety. Whether the trajectory of the tip of the boom 3, for example, the portion of the bucket 7 is inside or outside the regulation line La is determined to be within the allowable range. The regulation line La is defined by the load of the boom 3 itself and the bucket 7
It is set in advance in consideration of the overturning moment based on the load applied to the vehicle, the influence of wind, and the like. In the case of this embodiment,
Below the point A on the locus Lm in the most extended state where the boom 3 is extended to the maximum extent, it is regulated by the regulation line La. Lb is a correction line, and is a control that indicates the target trajectory of the tip of the boom 3 that is set to correct the operation command when the boom 3 reaches the regulation line La and is operated outside the allowable range. It is a line. Then
For example, when the tilting operation in the most extended state is performed on the boom 3 via the operation panel 8, the tip of the boom 3 descends along the locus Lm and reaches the point A, as described above. Then, the control system is switched from the closed loop control system to the open loop control system, and thereafter, the system automatically operates along the correction line Lb. As described above, when there is an operation command in the permissible inward direction, the operation is switched to the original closed loop control method and the operation is shifted to the normal operation control at that time.

Next, the open loop control for obtaining the locus along the correction line Lb will be described. In this example, the case where the correction line Lb is a straight line that descends in the vertical direction will be described. That is, during operation, the tip portion of the boom 3, for example, the point P on the bucket 7 is the regulation line L.
A case will be described in which a point intersecting with a is set as the current position and the vehicle is lowered vertically from there. Here, as shown in FIG. 1, the tip of the boom 3 from the support shaft 4, that is, the bucket 7
Let L be the length to the upper point P, and let L ₁ be the distance between the support shaft 4 and the point of action B of the hoisting cylinder 5 on the boom 3.
And the distance between the pivot point C of the undulating cylinder 5 is L ₂ , and the distance between the action point B and the pivot point C is S. Also, the piston diameter of the undulating cylinder 5 is A ₁ , and the extensible cylinder 6 is
Let A _{2 be} the piston diameter of. Now, assuming that the hydraulic oil is supplied to the undulating cylinder 5 by the flow rate Q ₁ in the state in which the undulation angle β is tilted from the horizontal state, the change angle α in the undulating direction, which changes accordingly, is as follows.

[Equation 1]

Further, when the change angle α changes with respect to the undulation angle β as described above, the hydraulic oil for the telescopic cylinder 6 necessary for vertically lowering the bucket 7 while reducing the boom 3 is used. The flow rate Q _{2 of} is as follows.

[Equation 2]

That is, the flow rate Q ₁ of the hydraulic oil according to the first equation
The change angle α based on the above equation is determined, and by substituting this into the second equation, the flow rate Q ₂ required for the vertical decrease can be obtained. That is, since a functional relationship regarding the flow rate of Q ₂ = f (Q ₁ ) is established, if each flow rate is adjusted so as to satisfy this relational expression, the bucket 7 will be lowered in the vertical direction. Therefore, when the P point of the bucket 7 exceeds the regulation line La in response to the turning operation,
With this flow rate relational expression, the hydraulic control of the undulating cylinder 5 and the expansion / contraction cylinder 6 are linked to perform open-loop control, so that it is possible to move down along the correction line Lb.

Next, the hydraulic pressure supply control to each cylinder will be described. FIG. 3 shows the hydraulic pressure supply circuit. In the figure, 9 to 11 are electromagnetic proportional flow rate control means with pressure compensation for the swivel motor 12, the undulating cylinder 5, and the telescopic cylinder 6, respectively, and electromagnetic proportional flow rate control valve sections 9a to 11a and pressure compensators 9b to 11b, respectively. Composed of. Then, as described above, when the tilting command for exceeding the regulation line La is issued to the boom 3 via the operation panel 8, when the tip portion of the boom 3 reaches the regulation line La. The control system is switched to the open loop control system, and thereafter, the controller (not shown) automatically controls along the correction line Lb.
That is, in accordance with the bending operation, the controller calculates the flow rate Q ₂ for the telescopic cylinder 6 corresponding to the flow rate Q ₁ for the undulating cylinder 5 using the flow rate relational expression, and the control means 11 based on the calculation result. Control is added in tandem. Thereby, in response to the tilting operation, the operation of the hoisting cylinder 5 by the control means 10 and the operation of the telescopic cylinder 6 by the control means 11 are linked to lower the tip end portion of the boom 3 along the correction line Lb. Loop control is possible. In the above description of the operation, when the tip of the boom 3 reaches the regulation line La in response to an operation command from the operation panel 8, the operation is once stopped, and when the operation beyond the regulation line La is performed, It is also possible to switch the control system to the open loop control system and perform the correction control. 13 in the figure
Is a hydraulic pressure source, 14 is a relief valve for safety, 15 is a bypass valve for setting circuit pressure, 16 and 17 are shuttle valves, and 18 is a tank.

[0012]

As described above, according to the present invention, since the open loop control system is adopted as the boom regulation control system and the detection signal of the sensor is not used, it is not affected by the sensor failure or the like. Since the system configuration is simple, the reliability as safety control technology is improved accordingly.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment in which the present invention is applied to an aerial work vehicle.

FIG. 2 is an explanatory diagram related to boom operation restriction.

FIG. 3 is a circuit diagram showing an embodiment relating to a hydraulic pressure supply circuit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Car body, 2 ... Revolving structure, 3 ... Boom, 4 ... Shaft, 5 ... Cylinder for undulation, 6 ... Cylinder for expansion / contraction, 7 ... Bucket, 8
... Operation panel, 9 to 11 ... Electromagnetic proportional flow rate control means, 9
a to 11a ... Electromagnetic proportional flow rate control valve section, 9b to 11b ... Pressure compensator, 12 ... Swing motor, 13 ... Hydraulic pressure source, 14 ... Relief valve, 15 ... Bypass valve, 16, 17
… Shuttle valve, 18… Tank

Claims (1)

[Claims] 1. In a boom operation control for performing posture control via a hoisting cylinder and a telescopic cylinder, the boom reaches a regulation line that defines a preset allowable range, and an operation outside the allowable range is performed. In this case, the control system for the hydraulic circuits of the hoisting cylinder and the telescopic cylinder is switched to the open loop control system, and the flow rate of the telescopic cylinder corresponding to the yaw operation is set in advance. Based on the calculation result and controlling the hydraulic circuit of the telescopic cylinder based on the calculation result, the tip of the boom operates along a predetermined correction line within the allowable range according to the tilting operation. A method of controlling a boom in an aerial work vehicle or the like, which is characterized in that the boom is controlled to be controlled.