JPH09175800A - Cargo carrying machine by means of force control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a heavy cargo to be handled lightly by detecting the magnitude of lifting force put forth in the anti-gravity direction, when a cargo is lifted up, by a sensor provided in the operating unit, which is held by a worker, and amplifying the hoisting force of a cargo carrying machine correspondingly to the magnitude of such lifting force. SOLUTION: When a cargo 16 of heavy weight is to be handled, first, a grip 12b is lifted upward and the force in the anti-gravity direction is detected by a force sensor 12a. An electropneumatic proportional valve 14b is driven by sending an electrical signal from the force sensor 12a to the control board 14a of a control unit 14 where signal amplification process is carried out. In other words, a force F1 in the anti-gravity direction added to the force sensor 12a is made as a hoisting force F2 of a cargo carrying machine by amplifying the force F1 by a parallel link mechanism composed of the control unit 14, a cylinder 11 and the respective arms and the operating unit 12 is made to act upon it. If it is (F1+F2)>=W, a cargo can be lifted up and if it is (F1+F2)<W by slacking the force F1 in the anti-gravity direction, the cargo can be unloaded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cargo handling machine having a lifting / lowering mechanism such as a parallelogram link type or a jib type, which lifts and lowers cargo using an actuator such as an air cylinder or an electric motor. .

[0002]

2. Description of the Related Art Conventionally, in this type of cargo handling machine, as a control method for raising and lowering a cargo, there are a method using an air cylinder as a driving source and a method using a motor as a driving source. There are a balance control method and a flow rate control method. In addition, a speed control method and a position control method are generally used when a motor is used as a drive source.

[0003]

Here, the contents and disadvantages of the conventional control method described above will be described.
First, the balance control method that uses an air cylinder as a drive source is a method that raises and lowers a cargo by constantly supplying air having a pressure corresponding to the weight of the cargo to the air cylinder. Since it was necessary to set the pressure, it was not possible to cope with changes in the weight of cargo.
Although it is possible to cope with changes in the weight of cargo by a complicated circuit structure and mechanism, there are problems such as deterioration of responsiveness and increase of cost. Further, the flow rate control method is a control method in which a flow rate control valve is provided between an air source and a cylinder, and the air of a constant pressure is adjusted by controlling the opening of the flow rate control valve to raise and lower the cargo. In this flow rate control method, the flow control valve is closed because it is a control method that closes the flow control valve to fix the amount of air in the cylinder when the lifting / lowering operation state shifts to the stop state. Immediately after that, an inertial force acting to ascend and descend acts on the elevating mechanism. By this inertial force,
The balance between the cylinder pressure and the weight of the cargo is lost, causing a bounce phenomenon. In other words, when the stop operation is performed from the ascending operation state, the elevating mechanism that has been performing the ascending operation even when the flow control valve is closed tries to further ascend due to inertial force. As a result, the cylinder pressure becomes lower than the pressure required to balance with the cargo, and the lifting mechanism with no inertial force tries to descend. The bounce phenomenon is attenuated and stopped while repeating this operation. Since the flow rate control method is a control method in which the above-mentioned bouncing phenomenon is always generated, there is a side that operability is deteriorated. Furthermore, the balance control method and the flow rate control method are control methods in which the lifting mechanism stops when the command is stopped and the neutral state is reached. Because of this, the neutral point is indispensable. Since this neutral point becomes the dead zone of the lifting operation, when moving to the lifting operation, the operation always starts from the dead zone, and the command signal is input too much due to the delay in the reaction speed to the command, and it moves at a speed faster than expected. There was a side that was lost.

Next, a speed control method and a position control method using an electric motor as a drive source are a control method for moving a motor up and down by driving the electric motor at a speed or a position change amount corresponding to the speed command signal or the position command signal. Therefore, if it is the same command signal, it will go up and down at the same speed regardless of the weight of the cargo, and the operator will not feel the weight of the cargo at all, so it is safe. There was a problem in terms of. For example, when a lifting instruction is given to the lifting mechanism while the cargo is being lifted, even if the cargo interferes with peripheral equipment, the operator does not feel the weight and continues to issue the lifting command. As a result, an excessive external force is applied to the cargo, and there is a risk that troubles such as dropping and damage of the cargo may occur. Further, in the speed control method and the position control method, like the above-described flow rate control method, the lifting mechanism stops when the command is stopped and the neutral state is set. Since the ascending operation and the descending operation by the descending command are performed, the neutral point is indispensable. Since this neutral point is the dead zone of the lifting operation, the operation always starts from the dead zone when shifting to the lifting operation, and the command signal is input too much due to the delay in the reaction speed to the command, and it moves at a speed faster than expected. There was such a side.

As a conventional example of this type, there is, for example, Japanese Patent Laid-Open No. 7-61800 (name of development: operating method for moving load supported in the air by intensifying device and operating portion therefor). . This device controls the direction and output from which the cargo is supported in the air as the starting point, and it has a neutral point as in the above-mentioned control methods, so it moves up and down. When moving to, the operation always starts from the dead zone, and the command signal was input too much due to the delay in the reaction speed to the command, and there was the aspect that it moved at a speed faster than expected.

[0006]

The present invention has solved the above-mentioned problems and common problems,
In a cargo handling machine having a mechanism for raising and lowering a cargo, a drive source for driving the lifting mechanism, and a control unit and an operating unit for controlling the driving source, a person has an operating unit and lifts the cargo. The magnitude of the lifting force in the anti-gravity direction (hereinafter abbreviated as "anti-gravity direction force")
It is detected by the force yancer provided on the operation unit, and the lifting force of the cargo handling machine is amplified according to the magnitude of the lifting force,
It is a cargo handling machine characterized by having a force control method for raising and lowering a cargo by its lifting force and lifting force.

Next, an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a conceptual diagram of the embodiment. One end of an A-arm 4 is fixed to a fixed shaft 5 on a side plate of a main body 3 connected to a support 1 and a swivel 2, and the other end of the A-arm 4 is connected to a one end of a C-arm 7 via a support shaft 6. And link arm 8 and B
The arm 9 and the A arm 4 and the B arm 9 form a parallel link mechanism. Further, a guide that supports the force point 10 of the parallel link mechanism is provided in a direction perpendicular to the rotation axis of the swivel base 2, and the force point 10 of the parallel link is increased by the cylinder 11 that can move up and down in parallel with the rotation axis of the swivel base 2. The operation unit 1 that moves up and down and has the force sensor 12a and the grip 12b incorporated therein is provided at the other end of the C arm 7.
2 is provided with a hook 13 for suspending a load. Further, regarding the control configuration, the control unit 14 includes a control board 14a and an electropneumatic proportional valve 14b.
a and the control board 14a are connected by the signal wire 15, and the control board 14a is connected to the electropneumatic proportional valve 14b. The electropneumatic proportional valve 14b is connected to the cylinder 11 via an air pipe. It is also possible to use a torque motor, a servomotor, or the like as a drive source to perform torque control.

[0008]

From the above structure, the operation will be described with reference to FIG. 1. W is the weight of the cargo 16; F1 is the force in the antigravity direction; F2 is the force in the antigravity direction. Lifting power. First, when trying to lift the grip 12b upward, the force in the antigravity direction is transmitted to the force sensor 12a. The force sensor 12a converts the received force into an electric signal and sends it to the control board 14a of the control unit 14 through the signal wire 15. The control board 14a amplifies the signal and drives the electropneumatic proportional valve 14b. The electropneumatic proportional valve 14b adjusts the pressure of the cylinder 11 so that the pressure is proportional to the signal. When the grip 12b is lifted to lift the cargo W by the hook 13, the anti-gravity direction force F1 applied to the force sensor 12a is amplified by the parallel link mechanism including the control unit 14, the cylinder 11 and the arms, and the cargo transporter. Lifting force F2
Next to the operation unit 12. When (F1 + F2) ≧ W, the cargo can be lifted, and when the force F1 in the antigravity direction is relaxed to (F1 + F2) <W, the cargo can be unloaded. Further describing the concept of force control from the function explanatory diagram of FIG. 2, b is the balance point at which the cargo is stationary in the air,
Fb is a force in the antigravity direction (hereinafter, abbreviated as "balance force") that is applied by hand to balance the cargo.
The straight line a is a characteristic curve of the control system. In this figure, a straight line is drawn for convenience, but it is not necessarily a straight line. or,
The figure shows the case of the force amplification ratio (F1 + F2) / F1 = 10, but the numerical values are for reference only and do not limit the technical scope of the present invention. Anti-gravity force F
1 is proportional to the weight W of the cargo 16 and inversely proportional to the force amplification ratio. The larger the force amplification ratio, the smaller the force F1 in the antigravity direction can support the weight W of the cargo 16 but the amplification ratio has an appropriate range from the viewpoint of stability of the control system and operational feeling. When attempting to move the grip 12b in the antigravity direction, the load is lifted when the force F1 in the antigravity direction exceeds the balance force Fb. The rising acceleration is proportional to the difference between the force F1 in the antigravity direction and the balance force Fb, and is inversely proportional to the weight W of the cargo 16.
That is, if the force F1 in the anti-gravity direction is increased, the force can be increased at a high speed, but since the acceleration of a heavy object is smaller than that of a light object, it is commensurate with the weight of the cargo. Can be raised at a safe speed. When the force F1 in the antigravity direction is the same as the balance force Fb, the balance state is achieved. When the lifting force of the grip 12b is loosened and the force F1 in the antigravity direction becomes smaller than the balance force Fb, the cargo is lowered.

[0009]

From the above structure and operation, the effect thereof will be described. By using the force control method according to the present invention, the force of the hand of the person trying to lift can be adjusted to freely raise the cargo work. , Neutral hold (balance), can be lowered. The force control method according to the present invention performs exactly the same control as the operation when a person transfers a cargo by himself, that is, the operation of raising and lowering the cargo by controlling only the force in the ascending direction. Therefore, it matches the natural movement of a human, and the operation feeling is almost the same as when a light cargo is held directly by hand. In addition, since the control directly amplifies the strength of the force in only one direction of the ascending direction, it does not have a neutral point and there is no dead zone in the control system, so not only the response is good but also the positioning accuracy is It has superior characteristics compared to conventional control methods.
Also, since the weight of the cargo to be handled is transmitted proportionally to the hands of people who actually carry out the cargo work, heavy cargo is heavy and light cargo is light, and the load condition is always transmitted to the worker. You can carry out cargo handling work with peace of mind.
Further, since the force control method shown in the embodiment controls the pressure of the air cylinder by using the electropneumatic proportional valve, it is possible to instantly lift a cargo material having high responsiveness and different weight, Work efficiency can be improved. Moreover, since the pressure is constantly adjusted, the bounce phenomenon does not occur, and a smooth operation feeling can be obtained. Further, since the hand and the cargo are moved as a unit, there is no troublesomeness of correcting the operation force applied to the operation lever while observing the lifting speed of the cargo unlike the conventional machine. Furthermore, since there is no need to use the conventional speed control method or position control method, the structure is relatively simple, and as a result, it is possible to manufacture at low cost, which is a great effect that has never been achieved.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an embodiment of the present invention.

FIG. 2 is a functional explanatory diagram of the embodiment of the present invention.

[Explanation of symbols]

 1 prop 2 swivel base 3 main body 4 A arm 5 fixed shaft 6 supporting shaft 7 C arm 8 link arm 9 B arm 10 power point 11 cylinder 12 operating part 12a force sensor 12b grip 13 hook 14 control part 14a control board 14b electro-pneumatic proportional Valve 15 Signal wire 16 Cargo material a Characteristic curve b Balance point F1 Anti-gravity direction force F2 Cargo lifting machine lifting force Fb Balance force W Cargo weight

Claims (2)

[Claims] 1. A cargo handling machine having a mechanism for raising and lowering a cargo, a drive source for driving the lifting mechanism, and a control unit and an operating unit for controlling the drive source. The force sensor installed in the operating unit detects the amount of lifting force in the anti-gravity direction when trying to lift a cargo, and the lifting force of the cargo carrier is determined according to the amount of lifting force. A cargo handling machine characterized by having a force control method for amplifying and lifting the cargo by a lifting force and a lifting force thereof. 2. The cargo handling machine according to claim 1, wherein an air cylinder is used as a drive source and an electropneumatic proportional valve is used as a control unit.