JP2010241518A - Cargo handling machine and method of controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cargo handling machine inexpensively and surely reducing operation force during balance mode. <P>SOLUTION: The pneumatic cargo handling machine 1 settable to the balance mode includes: a lift mechanism 5 movable vertically and horizontally and having a holding mechanism 8 for holding a predetermined cargo handling object 10; an air cylinder 20 for vertically driving the lift mechanism 5 by air pressure; a pressure proportional control valve 22 adjusting an air pressure supplied from an air source 21 to a predetermined pressure and supplying it to the air cylinder 20; and acceleration sensor 11 for detecting the vertical acceleration of the lift mechanism 5. In the balance mode, an output air pressure of the pressure proportional control valve 22 with respect to the air cylinder 20 is adjusted based on the acceleration information of the cargo handling object 10 obtained by the acceleration sensor 11, and information of the pressure within the air cylinder 20. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

   The present invention relates to a cargo handling machine for raising and lowering a cargo handling object, and more particularly to a cargo handling machine that drives a lifting mechanism by an air-type drive source.

Traditionally, in factory production lines or warehouses, a wide variety of transportation has been performed, including transportation associated with the removal and installation of relatively heavy equipment, transportation of semi-finished goods to the next process, and transportation of shipped products. Yes.
In the work of transporting various cargo handling items, a cargo handling machine that reduces labor and increases safety, has a small turn, and has mobility and simplicity is used.

As shown in FIG. 6, for example, the basic structure of the cargo handling machine 101 includes a main body 103 having a support column that is vertically raised from a bottom surface or a carriage.
An air cylinder 120 is disposed inside the main body 103 of the cargo handling machine 101, and an arm 104 (104 a to 104 c) constituting the elevating mechanism 105 is connected to the tip of the piston rod 120 a of the air cylinder 120 by a link mechanism. Has been.
This link mechanism serves as a power point when the arm 104 moves up and down, and the arm 104 is supported inside the main body 103, and this support portion serves as a fulcrum of the arm 104.

The arm 104c on the distal end side is provided with an operation box 109 having a load balance button 109a, a no-load balance button 109b, a grip button 109c, and a grip release button 109d. A gripping mechanism 108 for holding the cargo handling article 100 is provided at the tip of the arm 104c.
An air supply / exhaust control circuit 123 is connected to the air cylinder 120, and air is supplied from the air source 121 to the air cylinder 120 via the pressure proportional control valve 122 in response to an up / down command from the operation box 109. An exhaust process is performed.

In this case, for example, when an operation grip (not shown) is operated upward, air is supplied to the air cylinder 120 via the control circuit 123, whereby the piston rod 120a of the air cylinder 120 is downward in the figure. The cargo handling object 100 that is operated by the gripping mechanism 108 at the distal end of the arm 104c moves upward in accordance with the lever principle.
By the way, as such a cargo handling machine 101, there is a machine equipped with a control mode called a balance mode in which an operator 130 can directly grab the cargo handling article 100 and freely move and transfer it with a sense of weightlessness.

The circuit operation in the balance mode will be described with reference to FIG.
In the balance mode, the load handling machine 101 is supported by the piston rod 120a of the air cylinder 120 and the moment M1 of the counterclockwise force due to the weight of the arm 104 and the weight of the gripped load 100 with respect to the fulcrum A. By matching the moment M2 of the clockwise force caused by the force point B, the arm 104 is stopped (hereinafter referred to as a balance mode).

  In the balance mode, the output air pressure of the pressure proportional control valve 122 is controlled by the control circuit 123 so that the air pressure in the air cylinder 120 is always constant. When the operator 130 applies force to the cargo handling object 100 in this balanced state, the balance of the moments M1 and M2 of both these forces is lost, and the operator 130 can freely move the cargo handling object 100 in the direction in which the force is applied. It becomes possible.

  For example, an operation method in the case of transporting the cargo handling object 100 by the cargo handling machine 101 will be described. After the cargo handling object 100 is gripped by the gripping mechanism 108, when the operator 130 presses the load balance button 109 a, the control circuit 123 is proportional to the pressure. An air cylinder pressure (load balance pressure) when gripping the cargo handling object 100 is set to an input port (not shown) of the control valve 122, and the cargo handling machine 101 is set to the load balance mode.

When the cargo handling object 100 is conveyed to a predetermined place in the load balance mode and the cargo handling object 100 is landed, when the no-load balance button 109b is pressed, the cargo handling machine 101 is set to the no-load balance mode.
When the grip release button 109d is pressed in this state, the cargo handling object 100 is released (the grip is released). However, since the cargo handling machine 101 is set to the no-load balance mode, the cargo handling machine 101 does not rise. Stay stopped on the ground.

By the way, when working in the balance mode, compared with the work in the crane mode, there are merits such as quicker transfer work and easier positioning work, but the handling machine 101 with heavy (large) operating force is used. When working in a balance mode for a long time using the operator 130, the worker 130 may feel a great sense of fatigue or may cause muscle pain in some cases.
In recent years, there has been an increase in transportation work by elderly people and women, and there has been an increasing demand for lightening the operating force in the balance mode as much as possible.

For the reasons and requests as described above, when carrying the cargo handling object 100 in the balance mode, it is necessary to reduce the operation force during balancing as much as possible.
In the balance mode, if the weight of the cargo handling object 100 to be conveyed is light and the link mechanism of the cargo handling machine 101 is in an ideal state without friction or the like, the cargo handling object 100 can be moved with a relatively small operating force. However, in the actual cargo handling machine 101, the sliding friction between the piston 120b and the cylinder tube inner wall 120c when the air cylinder 120 operates, the friction of the link mechanism portion of each arm 104a to 104c, the cargo handling material 100 to be transported and the cargo handling machine 101 Due to the inertia of the arm 104, a certain amount of operating force is required.

In addition, when the weight of the cargo handling object 100 becomes heavy and the large cargo handling machine 101 becomes necessary, a particularly large operating force is required.
When the handling force of the load handling machine 101 in the balance mode is light, fatigue is not easily generated even if the operator 130 operates the load handling machine 101 for a long time. However, when the handling force becomes heavy, the work time is extended. In addition to this, there is a possibility that health problems of the worker 130 may occur as described above.

In order to reduce the operating force in the balance mode, it is necessary to study and improve each of the factors that increase the operating force.
In recent years, the problem of operating force has been improved by improving and reviewing the parts used, improving the quality, etc., but there are problems in the structure of the cargo handling machine, manufacturing costs, physical problems, etc. It was not easy to reduce the operating force with the cargo handling machine.

In order to solve the above-described problem of operating force, we invented a function for reducing operating force during balance using a force sensor in Japanese Patent Application No. 2005-285975 (JP 2007-91439 A: Patent Document 1). Proposed.
In the present invention, the force applied to the operation handle of the cargo handling machine by the operator in the balance mode is detected by the force sensor, and the cylinder pressure is adjusted to reduce the operation force. And, by installing this operation force reduction function in the cargo handling machine, the operation force during balancing could be greatly reduced.

However, the control method of the operation force reduction function has the following problems.
That is, in this prior art, an attempt was made to detect the operation force in the balance mode by attaching a force sensor to the operation handle. However, when the operation is performed by grasping a place other than the operation handle (for example, holding the arm of the handling machine) In such a case, the operation force cannot be detected, and the operation force reduction function does not function effectively.
In addition, the operation force detection unit (force sensor unit) including the force sensor in the balance mode can detect the operation force with high accuracy, has excellent responsiveness and can withstand long-term use. Since the structure is required, there is a problem that the manufacturing cost is high.

JP 2007-91439 A

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a cargo handling machine that can reliably reduce the operation force in the balance mode at a low cost.

The present invention made to achieve the above object is an air-type cargo handling machine that can be set in a balance mode, and is configured to be movable in the vertical and horizontal directions, and has a holding mechanism that holds a predetermined cargo handling object. Elevating mechanism, an air cylinder that drives the elevating mechanism in the vertical direction by air pressure, and pressure proportional control that adjusts the air pressure supplied from a predetermined air source to a predetermined pressure and supplies the air cylinder to the air cylinder An acceleration information detecting sensor for detecting acceleration information in the vertical direction of the elevating mechanism, and the acceleration of the cargo item obtained based on information from the acceleration information detecting sensor in the balance mode The output air pressure of the pressure proportional control valve for the air cylinder is adjusted based on the information and the pressure information in the air cylinder. Are those configured urchin.
In the present invention, there is provided a pressure sensor for detecting the pressure in the air cylinder, and based on the information obtained by the acceleration detection sensor and the pressure information obtained by the pressure sensor in the balance mode. This is also effective when the output air pressure of the pressure proportional control valve with respect to the air cylinder is adjusted.
The present invention is also effective when the holding mechanism is provided with an acceleration sensor for detecting vertical acceleration as the acceleration information detection sensor.
The present invention is also effective when the lifting mechanism has an arm for lifting a cargo handling object, and the arm is provided with a gyro sensor or a tilt sensor as the acceleration information detection sensor.
The present invention is also effective when a position sensor or a speed sensor is provided as the acceleration information detection sensor on the piston rod of the air cylinder.
On the other hand, the present invention provides a method for controlling any of the above-described cargo handling machines, wherein an operator lifts the lifting mechanism in a state where a cargo handling object is held by the lifting mechanism and the cargo handling machine is set to a balance mode. When moving in the direction or downward, according to the acceleration information of the cargo item obtained based on the information from the acceleration information detection sensor, the lifting mechanism is urged in the movement direction, It is the control method of the cargo handling machine which controls the output air pressure of the said pressure proportional control valve with respect to the said air cylinder.

  In the case of the present invention, in the balance mode, the output air pressure of the pressure proportional control valve to the air cylinder based on the acceleration information of the cargo handling object obtained based on the information from the acceleration information detection sensor and the pressure information in the air cylinder. Therefore, even if the operator grips any part of the moving part (operating part, operating handle, cargo item, arm, etc.) by the lifting mechanism, the operating force is reliably reduced. Can be made.

Therefore, according to the present invention, the balance function can be effectively utilized, and a wide range of work can be handled.
Further, in the present invention, if a small and low-cost acceleration sensor based on MEMS (Micro Electro Mechanical Systems) technology is used as the acceleration information detection sensor, a cargo handling machine having an operation force reducing function can be provided at low cost. Can do.

  According to the present invention, since the operation force in the balance mode can be surely and greatly reduced, even if the worker performs the work in the balance mode for a long time, the worker can work without feeling tired.

Schematic which shows the external appearance structure of embodiment of the cargo handling machine which concerns on this invention. Block diagram showing the control system of the cargo handling machine The conceptual diagram for demonstrating the basic principle of the operation force reduction function by this invention The block diagram which shows the control system of other embodiment of the cargo handling machine which concerns on this invention. The block diagram which shows the control system of further another embodiment of the cargo handling machine which concerns on this invention. Block diagram showing the control system of a cargo handling machine according to the prior art

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram showing an external configuration of an embodiment of a cargo handling machine according to the present invention, and FIG. 2 is a block diagram showing a control system of the cargo handling machine.
As shown in FIG. 1, a cargo handling machine 1 according to the present embodiment has a support column 2 erected vertically, and a main body 3 including a control box is provided above the support column 2.

  As shown in FIG. 2, an air cylinder 20 similar to the prior art is provided in the main body 3. The air cylinder 20 is connected to an air source 21 via an air piping portion 28, a pressure proportional control valve 22, and an air piping portion 27.

  The cargo handling machine 1 includes an elevating mechanism 5 for elevating and transporting the cargo handling object 10, and the elevating mechanism 5 includes an arm 4 including first to third arms 4 a to 4 c. Here, the first arm 4a is supported at the fulcrum A so as to constitute a lever in a state in which the first arm 4a can be rotated by a predetermined angle in the vertical direction, and the force point B is driven by the piston rod 20a of the air cylinder 20. Are linked by a link mechanism.

Further, the first arm 4 a is supported so as to turn in the horizontal direction around the central axis of the support column 2.
The second arm 4b is connected to the distal end of the first arm 4a in a state that always maintains a horizontal state via the joint portion 6, and is further connected to the distal end (lower end) of the second arm 4b. Are connected so that the third arm 4c extending in the vertical direction can rotate in the horizontal direction.

An operation box 9 having an operation grip 90a is attached to the lower part of the third arm 4c.
Here, the operation box 9 is provided with a load balance button 9a, a no-load balance button 9b, a grip button 9c, and a grip release button 9d.

The load balance button 9 a, the no-load balance button 9 b, the grip button 9 c, and the grip release button 9 d are connected to the control circuit 23 and configured to send an on / off signal to the control circuit 23.
The control circuit 23 includes a microcomputer, a memory, and the like. The control circuit 23 is electrically connected to the pressure proportional control valve 22 via a D / A converter 26, and sends various control signals to the pressure proportional control valve 22 to supply pressure. The proportional control valve 22 is controlled.

Furthermore, a gripping mechanism (holding mechanism) 8 that holds (holds) the cargo handling object 10 by, for example, air suction is attached to the lower end portion of the third arm 4c.
The gripping mechanism 8 is configured to grip the cargo item 10 or release the gripping by operating a grip button 9 c or a grip release button 9 d provided on the operation box 9.

In the present embodiment, the pressure of the air supplied from the air source 21 is adjusted by the pressure proportional control valve 22 according to a command from the control circuit 23 and output to the air cylinder 20.
Further, a pressure sensor 24 is provided at the subsequent stage of the pressure proportional control valve 22. This pressure sensor 24 measures the pressure in the air piping section 28 between the pressure proportional control valve 22 and the air cylinder 20, and is electrically connected to the control circuit 23 via the A / D converter 25. The measured pressure data is sent to the control circuit 23.

  In the present embodiment, the gripping mechanism 8 is provided with an acceleration sensor 11 that detects vertical acceleration. The acceleration sensor 11 is electrically connected to the control circuit 23 via the A / D converter 25 and sends the detected acceleration data to the control circuit 23.

FIG. 3 is a conceptual diagram for explaining the basic principle of the operation force reducing function according to the present invention.
Here, in order to simplify the description, the description will be made assuming an ideal cargo handling machine.

That is, the cargo handling machine 1 to be described below is an ideal mechanism in which there is no sliding friction in the air cylinder 20 and the joints and other mechanical parts of the arm 4 have no friction. Is assumed to be concentrated at the point of action C in the figure.
Further, it is assumed that the air supply from the pressure proportional control valve 22 into the air cylinder 20 can be instantaneously performed without delay, and further, if the input set pressure of the pressure proportional control valve 22 is constant, the air cylinder can be used in any device state. Assume that the air pressure in 20 can be kept constant.

First, assuming that the air pressure in the air cylinder 20 is set to P (load balance pressure) and the load balance mode is set, the moment of force in the clockwise direction and the counterclockwise direction at the fulcrum A becomes equal, so that It holds.

(Ma + Mw) · G · La = P · S · Lb (G: gravity acceleration)
Mt · G · La = P · S · Lb (1)

Here, the effective length of the arm 4 is La, the effective length of the arm 4 in the main body 3 is Lb, the weight of the cargo handling object 10 is Ma, the weight of the arm 4 is Mw, and Mt = Ma + Mw.
In this balance mode, when the operator 30 applies a force to the cargo handling object 10 gripped by the cargo handling machine 1 and moves it upward with an acceleration a, a force F represented by the following equation is required.

F = (Ma + Mw) · a = Mt · a Equation (2)

Further, in this balance mode, if the pressure in the air cylinder 20 is increased by ΔP, assuming that the force generated at the action point C at the tip of the arm 4 is F1, F1 is expressed by the following equation.

F1 ・ La = Lb ・ ΔP ・ S
F1 = ΔP · S · Lb / La (3)

In the state where the air pressure in the air cylinder 20 is increased by ΔP, if F2 is the force required for the operator 30 to apply force to the cargo handling object 10 and increase it with acceleration a, F2 is expressed by the following equation (2), From the formula (3), it is expressed by the following formula.

F = F1 + F2 = Mt · a
F2 = Mt · a−F1
= Mt · a−ΔP · S · Lb / La (4)

In the equation (4), the pressure increase ΔP in the air cylinder 20 is set as follows.

ΔP = k · Mt · a (k is a proportional constant) (5)

When Formula (5) is substituted into Formula (4), F2 is expressed by the following formula.

F2 = Mt.a-k.Mt.a.S.Lb / La
= Mt · a (1-k · S · Lb / La) (6)

In formula (6), in order to make the operating force F2 zero as much as possible,

1-k · S · Lb / La = 0 Formula (7)

Should just hold.
When the proportionality constant k set in Expression (7) to Expression (5) is obtained,

k = La / (S · Lb) (8)

become.

From the formula (1), the total weight Mt obtained by adding the weight of the arm 4 and the weight of the cargo handling material 10 is expressed by the following formula.

Mt = P · S · Lb / (G · La) (9)

It is considered that the operating force F2 in the balance mode can be reduced to zero as much as possible by increasing or decreasing the pressure in the air cylinder 20 from the air pressure in the balance mode.

The air pressure increase / decrease amount ΔP set in the air cylinder 20 in the balance mode can be obtained by the following equation by substituting Equation (8) and Equation (9) into Equation (5).

ΔP = k · Mt · a = {La / (S · Lb)} {P · S · Lb / (G · La)} · a
= P · a / G (10)

Expression (10) is set so that the pressure increase ΔP of the air cylinder 20 in the balance mode set to reduce the operating force is proportional to the acceleration at the tip of the arm 4 and the pressure in the air cylinder 20 in the balance mode. It shows that it should be done.

Therefore, Equation (10) is rewritten as the following equation using the proportionality constant K.

ΔP = K · P · a (K = 0 to 1 / G) Equation (11)

In Expression (11), when K = 0, ΔP = 0. Therefore, F2 = Mt · a from Expression (4), and the operation force reduction function becomes invalid.
On the other hand, if K = 1 / G, ΔP = P · a / G and F2 = 0, indicating that the operating force during balancing can be set to 0 (ideal state).

However, in actual work, if the operating force is too light, the elevating mechanism 5 moves with a slight force, which may be difficult to use.
For this reason, it is necessary to set the value of K according to the work content to adjust the operating force at the time of balancing, and to provide a threshold value for determining whether or not to process the detected acceleration value as valid.

Hereinafter, specific examples of the present invention will be described with reference to the embodiments shown in FIG. 2, FIG. 4 and FIG.
In the cargo handling machine 1 according to the embodiment shown in FIG. 2, the acceleration in the vertical direction of the cargo handling object 10 is detected by the acceleration sensor 11 provided in the gripping mechanism 8, and the air pressure in the air cylinder 20 is as follows. The air pressure supplied to the air cylinder 20 (≈air pressure in the air cylinder 20) is detected by a pressure sensor 24 provided in an air piping portion 28 connecting the pressure proportional control valve 22 to the pressure 20.

In this case, the information on the cylinder pressure from the pressure sensor 24 detects information such as the weight of the cargo handling article 10 and the weight of the cargo handling machine 1 as equivalent.
The sensor information detected by the acceleration sensor 11 and the pressure sensor 24 is read into the control circuit 23 via the A / D converter 25.
Setting of the input set pressure to the pressure proportional control valve 22 is performed via the D / A converter 26. When the input set pressure to the pressure proportional control valve 22 is kept constant, the air pressure in the air cylinder 20 is kept constant regardless of the position of the piston rod 20a.

  When the operator 30 presses the load balance button 9 a of the operation box 9, the air pressure in the air cylinder 20 is set so that the balance state can be maintained while the cargo handling object 10 is gripped. When the balance button 9b is pressed, the balance state is set when the cargo handling object 10 is released.

In such a configuration, for example, it is assumed that the load handling mode 10 is held and the load balance mode is set.
In this state, when the operator 30 applies a force to the gripping mechanism 8 or the gripping article 10 or the like to operate in the vertical direction, the control circuit 23 uses the output information from the acceleration sensor 11 provided in the gripping mechanism 8 to grip the gripping mechanism 8. It is possible to know the vertical direction in which the mechanism 8 (or the arm 4) is moved and the magnitude of the acceleration at that time.

Here, assuming that the acceleration detected during this operation is a and the load balance pressure in the air cylinder 20 is P, the air pressure P ′ in the air cylinder 20 newly set via the pressure proportional control valve 22 when detecting the acceleration. Is represented by the following equation based on the equation (11).
In this case, the acceleration a is a positive value when moving in the upward direction, and a negative value when moving in the downward direction.

P ′ = P + ΔP
= P + K · P · a (K = 0 to 1 / G)
= P (1 + K · a) (12)

In Equation (12), for example, assuming a case of moving in the upward direction by 0.1 [G], the control force at this time is controlled to approach 0 as much as possible by controlling the pressure proportional control valve 22 ( K = 1 / G), and the air pressure in the air cylinder 20 is set as follows.

P ′ = P (1+ (1 / G) · 0.1G) = 1.1 × P (13)

Equation (13) indicates that when the load handling object 10 is raised by 0.1 G by the lifting mechanism 5, the operating force can be reduced to 0 as much as possible by increasing the balance pressure in the air cylinder 20 by 1.1 times. Show.

  In the conventional cargo handling machine, if an operator tries to move the cargo handling object in the upward direction at an acceleration of 0.1 G, the ideal cargo handling machine requires a force of Mt (= Ma + Mw) × 0.1 G. In the cargo handling machine 1 according to the embodiment, an operation force necessary for moving the cargo handling object 10 in the upward direction at the same acceleration can be obtained by increasing the air pressure in the air cylinder 20. 30 shows that if a slight force is applied to the cargo handling object 10 or the gripping mechanism 8, the elevating mechanism 5 can be moved at a desired acceleration by simply attaching the hand.

  However, the above explanation was made assuming an ideal cargo handling machine.In an actual cargo handling machine, there is a delay in the friction of each part of the cargo handling machine and the response of the control processing. It cannot be set to zero at all. However, it has been confirmed that even in an actual cargo handling machine, the operating force in the balance mode can be greatly reduced by the configuration of the cargo handling machine 1 of the present embodiment.

As described above, according to the present embodiment, the operation force in the balance mode can be greatly reduced, so that the worker can work without feeling a feeling of fatigue even when working in the balance mode for a long time. It can be carried out.
Moreover, since the acceleration sensor 11 used in this Embodiment can be comprised with the small and low-cost components by MEMS technology, the cargo handling machine 1 excellent in workability | operativity at low cost can be provided.

  Furthermore, in the case of an operation force reduction function using a force sensor using a conventional strain gauge or the like, there is a limitation due to usage conditions such as, for example, it is necessary to grip and move a place where the operation force can be detected, such as an operation handle. However, in the present embodiment, since the acceleration sensor 11 can detect the movement (acceleration) as long as the arm 4 of the cargo handling machine 1 moves in the vertical direction, the operation grip 90a, the gripping mechanism 8, the cargo handling object 10, the arm 4, etc. The manipulation force reduction function is enabled no matter what place is gripped. Therefore, the balance function can be effectively used, and a wide range of work can be handled.

In the above embodiment, the case where the acceleration sensor 11 is mounted on the gripping mechanism 8 has been described as an example. However, the acceleration sensor 11 may be attached to the arm 4, or the inside of the main body 3 of the cargo handling machine 1. The same effect can be obtained even if the piston rod 20a or the force point B portion is equipped.
In this case, for example, when the acceleration sensor 11 is attached to the force point B portion in the main body 3, the acceleration that can be detected is small, but after the control circuit 23 reads the acceleration information, the read acceleration value is multiplied by the arm ratio ( La / Lb), it is equivalent to the case where the gripping mechanism 8 is equipped.

FIG. 4 is a block diagram showing a control system according to another embodiment of the present invention. Hereinafter, parts corresponding to those in the above embodiment are given the same reference numerals, and detailed descriptions thereof are omitted.
In the embodiment shown in FIG. 2, the acceleration sensor 11 is provided in the gripping mechanism 8 to detect the acceleration during the up-and-down operation of the lifting mechanism 5. However, in this embodiment, as shown in FIG. A gyro sensor 31 or a tilt sensor 32 is provided on the arm 4 of 1A.

The gyro sensor 31 or the inclination sensor 32 is electrically connected to the control circuit 23 via the A / D converter 25 and sends the detected data to the control circuit 23.
Here, in the case of the gyro sensor 31, the angular velocity when the arm 4 is moved up and down is detected. The angular velocity information detected by the gyro sensor 31 is differentiated by the first floor time to calculate the angular acceleration. If the effective arm length is multiplied by the angular acceleration, the acceleration at the tip of the arm 4 can be calculated.

On the other hand, since the tilt sensor 32 is a sensor that detects an angle component, the tip end portion of the arm 4 is calculated by calculating the angular acceleration by differentiating the angle information detected by the tilt sensor 32 by the second floor time. Acceleration information can be calculated.
Then, by controlling the pressure proportional control valve 22 based on the acceleration information thus obtained, the balance pressure in the air cylinder 20 is set to a predetermined value, and the operating force is made as close to 0 as possible. To do.

Also in the present embodiment described above, the operation force in the balance mode can be greatly reduced as in the above embodiment, so that the worker 30 feels fatigue even when working in the balance mode for a long time. You can work without it.
In addition, according to the present embodiment, since the low-cost gyro sensor 31 based on the MEMS technology is used, it is possible to detect the angular acceleration of the arm 4 and calculate the acceleration of the tip of the arm 4 at a low cost.
Since other configurations and operational effects are the same as those of the above-described embodiment, detailed description thereof is omitted.

FIG. 5 is a block diagram showing a control system according to still another embodiment of the present invention. Hereinafter, the same reference numerals are given to the portions corresponding to the above-described embodiment, and the detailed description thereof will be omitted.
In the present embodiment, as shown in FIG. 5, a position detection sensor 41 or a speed detection sensor 42 is provided on the piston rod 20a on the main body 3 side of the cargo handling machine 1B.

The position detection sensor 41 or the speed detection sensor 42 is electrically connected to the control circuit 23 via the A / D converter 25, and sends the detected data to the control circuit 23.
Here, when the position detection sensor 41 is provided in the piston rod 20a, the acceleration can be calculated by performing second-order time differentiation.
On the other hand, in the case of the speed detection sensor 42, acceleration can be calculated by performing first-order time differentiation.
Then, by controlling the pressure proportional control valve 22 based on the acceleration information thus obtained, the balance pressure in the air cylinder 20 is set to a predetermined value, and the operating force is made as close to 0 as possible. To do.

Also in the present embodiment described above, the operation force in the balance mode can be greatly reduced as in the above embodiment, so that the worker 30 feels fatigue even when working in the balance mode for a long time. You can work without it.
Further, according to the present embodiment, the present invention is realized by using sensors that have been rapidly spread in recent years by MEMS technology, such as the acceleration sensor 11 and the gyro sensor 31 in the embodiments of FIGS. However, according to the present embodiment, there is an effect that the present invention can be realized even if a conventional sensor such as a linear scale is used.
Since other configurations and operational effects are the same as those of the above-described embodiment, detailed description thereof is omitted.

The present invention is not limited to the above-described embodiment, and various changes can be made.
For example, in the embodiment shown in FIG. 2, the acceleration pressure of the cargo handling machine 1 and the air pressure in the air cylinder 20 during the balance mode are detected by the acceleration sensor 11 and the pressure sensor 24 to control the balance pressure. Even if the acceleration is detected and controlled by the acceleration sensor 11 without detecting the air pressure in the air cylinder 20, a certain degree of operation force reduction effect can be obtained.

  The air pressure in the air cylinder 20 uses the load or no-load balance pressure information stored and registered in the control circuit 23 in advance without detecting the cylinder pressure in the load balance mode by the pressure sensor 24. It is also possible to calculate by calculating. In this case, there is an advantage that the apparatus configuration can be simplified.

Further, in the embodiment shown in FIG. 2, the case where the low-cost pressure sensor 24 and the acceleration sensor 11 are used to realize the operation force reduction function of the present invention at a low price has been described. As will be understood, the same effect can be obtained by using the weight of the load handling object 10 with a weight sensor such as a load cell instead of the pressure sensor to directly measure the weight and use it for control.
Furthermore, in each of the above-described embodiments, the arm type cargo handling machine has been described as an example, but also in a hoist type cargo handling machine equipped with a balance mode, by installing an acceleration sensor in the gripping mechanism portion of the cargo handling object, It is clear that the present invention can be applied in the same manner as an arm type cargo handling machine.

DESCRIPTION OF SYMBOLS 1 ... Material handling machine 3 ... Main body 4 ... Arm 5 ... Elevating mechanism 8 ... Grip mechanism 9 ... Operation box 10 ... Load handling object 11 ... Acceleration sensor (acceleration information detection sensor)
20 ... Air cylinder 21 ... Air source 22 ... Pressure proportional control valve 23 ... Control circuit 24 ... Pressure sensor

Claims (6)

An air-type cargo handling machine that can be set to balance mode,
An elevating mechanism configured to be movable in the vertical direction and the horizontal direction, and having a holding mechanism for holding a predetermined cargo item;
An air cylinder for driving the lifting mechanism in the vertical direction by the pressure of air;
A pressure proportional control valve that adjusts the pressure of air supplied from a predetermined air source to a predetermined pressure and supplies the air cylinder;
An acceleration information detection sensor for detecting acceleration information in the vertical direction of the lifting mechanism;
In the balance mode, the output air pressure of the pressure proportional control valve to the air cylinder based on the acceleration information of the cargo item obtained based on the information from the acceleration information detection sensor and the pressure information in the air cylinder. A cargo handling machine that is configured to adjust the.   A pressure sensor for detecting the pressure in the air cylinder, and in the balance mode, based on the information obtained by the acceleration detection sensor and the pressure information obtained by the pressure sensor; The cargo handling machine according to claim 1, wherein the cargo handling machine is configured to adjust an output air pressure of the pressure proportional control valve.   The cargo handling machine according to claim 1, wherein the holding mechanism is provided with an acceleration sensor that detects acceleration in the vertical direction as the acceleration information detection sensor.   The cargo handling machine according to any one of claims 1 and 2, wherein the lifting mechanism has an arm for lifting a cargo handling article, and the arm is provided with a gyro sensor or a tilt sensor as the acceleration information detection sensor. .   The cargo handling machine according to claim 1, wherein a position sensor or a speed sensor is provided as a sensor for detecting acceleration information on a piston rod of the air cylinder. A method for controlling a cargo handling machine according to any one of claims 1 to 5,
In a state where the lifting mechanism holds the cargo handling object and the cargo handling machine is set to the balance mode,
When the operator moves the elevating mechanism upward or downward, the elevating mechanism is moved in the moving direction according to the acceleration information of the cargo item obtained based on information from the acceleration information detecting sensor. A control method for a cargo handling machine that controls an output air pressure of the pressure proportional control valve with respect to the air cylinder so that the air cylinder is biased.

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