JP2003082701A - Locus deviation preventive device of articulated arm work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a locus deviation preventive device of an articulated arm work machine causing no damage of a sheet pile, a pile and an arm even when becoming an overload in locus control of an articulated arm. SOLUTION: Four arms 1 to 4 constitute the articulated arm 130 for controlling a locus, and are driven by hydraulic cylinders 1c to 4c. Pressure sensors 51 to 58 are installed in respective bottom chambers and rod chambers of the hydraulic cylinders 1c and 4c. An overload detecting device 50 outputs a stopping signal to a controller 20 so as to stop the locus control of the hydraulic cylinders 1c to 4c when either pressure of the hydraulic cylinders 1c to 4c detected by the pressure sensors 51 to 58 exceeds upper limit preset pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a trajectory deviation prevention device for a multi-joint arm working machine having a trajectory-controlled multi-joint arm for pulling out and press-fitting sheet piles, piles and the like.

[0002]

2. Description of the Related Art In a multi-joint arm working machine that attaches an attachment such as a vibro hammer to the tip of a multi-joint arm to perform work, a device for controlling the trajectory of the multi-joint arm is known. The articulated arm working machine has a plurality of arms swingably connected to each other so that it can be compactly operated to perform pile construction work especially in a narrow construction site such as an urban area. Furthermore, by controlling the trajectory of the end of the multi-joint arm to which the attachment is attached, it is possible to accurately pull out and press fit the sheet pile, the pile, and the like.

[0003]

However, the force input and the pull-out force of the sheet pile, the pile, etc. by the attachment change depending on the geology, the hardness of the ground, the existence of obstacles in the ground, and the like. When the sheet pile is pulled out by the trajectory control and sticks to sand or the like that has been compacted, the sheet pile cannot be pulled out smoothly and the pressure of the hydraulic cylinder that drives the multi-joint arm rises. If the pressure of the hydraulic cylinder exceeds the set pressure of the overload relief valve that prevents the overload condition, the pressure oil supplied to the hydraulic cylinder is relieved, and the hydraulic cylinder under flow control runs away. There is a problem. Since the multi-joint arm controls the trajectory, it tries to correct the displacement of the tip of the multi-joint arm caused by the escape of the hydraulic cylinder. However, if the trajectory control does not catch up with the runaway of the hydraulic cylinder or overshoots the runaway of the hydraulic cylinder and corrects too much, the displacement of the arm tip deteriorates the construction accuracy of the sheet pile or the pile.
Further, the sheet pile, the pile, the front attachment, and the arm may be bent or damaged.

The present invention provides a trajectory deviation preventing device for a multi-joint arm working machine and a multi-joint arm work which does not damage the sheet pile, the pile, or the arm even if an overload occurs during the trajectory control of the multi-joint arm. The purpose is to provide a machine.

[0005]

According to the present invention, a locus control target portion of an articulated arm having at least first and second arms is moved along a predetermined locus by the first and second hydraulic cylinders. It is applied to an articulated arm work machine whose trajectory is controlled to move. And the first and second
Load detector for detecting the load of the hydraulic cylinder, and a judging device for judging whether the load of the first or second hydraulic cylinder detected by the load detector exceeds a set value, and Alternatively, it is possible to achieve the above object by including a control device that stops or decelerates the trajectory control by the first and second hydraulic cylinders when it is determined that the load of the second hydraulic cylinder exceeds a set value. To do.

The set value is composed of an upper limit set value and a lower limit set value, and when the determination device determines that the load of the first or second hydraulic cylinder exceeds the upper limit set pressure, the control device determines When the locus control by the first and second hydraulic cylinders is stopped or decelerated and it is determined that the lower limit setting value is not reached, it is preferable to restore the locus control during stop or deceleration.

It is preferable that the set value of the load for stopping or decelerating the trajectory control of the first hydraulic cylinder or the second hydraulic cylinder be set differently for the first and second hydraulic cylinders.

The articulated arm working machine according to the present invention achieves the above object by including the trajectory deviation prevention device for the articulated arm working machine according to any one of claims 1 to 3.

[0009]

1 is a diagram showing a system of a trajectory deviation prevention device for an articulated arm working machine according to the present invention. FIG. 2 is a side view of an articulated arm working machine equipped with a trajectory control device. However, the front attachment is omitted for clarity. As shown in FIGS. 1 and 2, the articulated arm working machine includes a lower traveling body 110 and an upper rotating body 1 rotatably attached to the lower traveling body 110.
20 and an articulated arm 130 attached to the upper swing body 120.

The multi-joint arm 130 is a hydraulic cylinder 1c.
The first arm 1 connected to the upper revolving structure 120 so as to be able to move up and down, and the first arm 1 by the hydraulic cylinder 2c.
To the second arm 2 swingably connected to the second arm 2 by a hydraulic cylinder 3c.
An arm 3 and a fourth arm 4 swingably connected to the third arm 3 by a hydraulic cylinder 4 are provided. Fourth
A front attachment (not shown) such as a vibro hammer is pin-connected to the tip A of the arm 4.

In the vicinity of the fulcrum of each arm which constitutes the articulated arm 130, angle detectors 11, 12, 13,
14 is attached. The angle detector 11 is provided at the undulating fulcrum of the first arm 1 and detects the ground angle of the first arm 1 by a well-known pendulum mechanism and potentiometer. The angle detectors 12 to 14 include the second arm 2, the third arm 3,
Relative angles with respect to the respective arms are detected by a well-known lever mechanism and a potentiometer which are respectively provided at the swing fulcrums of the fourth arm 4. Each detected arm angle is input to the controller 20. Further, a work direction speed command for the tip of the fourth arm 4 by the trajectory control lever 21 provided in the driver's seat is also input to the controller 20.

The controller 20 performs calculations for controlling the trajectory of the articulated arm 130 from the input arm angle and speed command.

FIG. 2 shows an example of the trajectory control target straight line L. That is, the controller 20 controls the articulated arm 130 so that the tip A of the fourth arm 4 moves vertically along the trajectory control target straight line L. In the articulated arm working machine described in the present embodiment, the locus control is performed by controlling the hydraulic cylinder 2c that drives the second arm 2 and the hydraulic cylinder 3c that drives the third arm 3. The controller 20 also performs processing for preventing deviation of the trajectory from the trajectory-controlled state, which will be described later.

The hydraulic cylinders 2c, 3c are driven to expand and contract by pressure oil supplied from a hydraulic source (not shown). The electromagnetic proportional directional control valves 22 and 23 control the flow rate and direction of pressure oil from a hydraulic source (not shown) supplied to the hydraulic cylinder 2c that drives the second arm 2 and the hydraulic cylinder 3c that drives the third arm 3, respectively. It is a control valve that controls. The controller 20 outputs a flow rate control command value (PWM) to the electromagnetic proportional directional control valves 22 and 23 based on the input arm angle and the speed command input from the trajectory control lever.
Calculate the current command value). Then, the electromagnetic proportional direction switching valves 22 and 23 are switched according to the flow rate control command value to control the flow rate and direction of the pressure oil supplied to the hydraulic cylinders 2c and 3c, thereby controlling the trajectory of the articulated arm 130. To do.

The trajectory control of the articulated arm 130 has been described above. The trajectory deviation prevention device for a multi-joint arm working machine according to the present invention prevents the hydraulic cylinder from running away and damaging the arm or the like when the trajectory-controlled multi-joint arm falls into an overloaded state.

FIG. 2 shows a diagram in which the hydraulic cylinder for driving the articulated arm 130 escapes at the time of overload and the tip of the fourth arm 4 deviates to A '. As described above, according to the trajectory control of the multi-joint arm 130 calculated by the controller 20, the tip A of the fourth arm 4 moves along the trajectory control target straight line L. However, for example, when a pile is pulled out by using a vibro hammer as a front attachment, the pile and the ground may come into close contact with each other via sand or the like, and the pile may not be pulled out.

The articulated arm 130 without pulling out the pile.
When the trajectory control of the robot is continuously pulled out, a plurality of hydraulic cylinders 1c, 2c, 3 which drive the articulated arm 130 are driven.
The hydraulic pressures of c and 4c increase. When the pressure oil in one of the hydraulic cylinders reaches the set pressure of the relief valve, the pressure oil in the hydraulic cylinder whose flow rate is controlled is relieved and the hydraulic cylinder runs away. As a result, the articulated arm 13
The posture of 0 collapses, and as shown in FIG.
The tip of 0 deviates from A at the time of safety to A'at the time of overload.
As a result, the pile, sheet pile, or the like that was about to be pulled out by the vibro hammer may be damaged. Also,
The accuracy of construction of the piles and sheet piles at the time of press fitting may be deteriorated, and the arm may be bent or damaged.

Therefore, the trajectory deviation preventing apparatus for a multi-joint arm working machine according to the present invention is a trajectory-controlled multi-joint arm 1.
When 30 falls into an overloaded state, operations such as pull-out / press-fitting by trajectory control are stopped so that the posture of the arm is not disturbed. When the pulling-out / press-fitting operations are stopped, the vibro hammer, etc., vibrates at that position to release the close contact between the sheet pile or pile and the ground, reducing the frictional force.
This reduces the load on the articulated arm 130,
It is possible to perform operations such as pulling out and press fitting without causing damage to the arm and the like. The trajectory deviation prevention control of the articulated arm working machine will be described in detail below.

As shown in FIG. 1, pressure sensors 51, 52, 5 are provided in the bottom chamber and rod chamber of the hydraulic cylinders 1c, 2c, 3c, 4c for driving the articulated arm 130, respectively.
3, 54, 55, 56, 57, 58 are attached. The pressures on the bottom chamber side and the rod chamber side of the hydraulic cylinders 1c, 2c, 3c, 4c detected by the pressure sensors 51 to 58 are input to the overload detection device 50, respectively. Further, a signal from an on / off switch 60 for selecting whether to set or cancel the trajectory deviation prevention control function of the multi-joint arm is also input to the overload detection device 50. Further, the overload detection device 50 includes the above-described articulated arm 1
A controller 20 for controlling the locus of 30 and an alarm device 6
1 and the operation display device 62 are connected.

The overload detection device 50 determines whether or not the articulated arm 130 is in an overloaded state based on the input pressure signal. The articulated arm 130 includes four arms 1 to 1.
4 and the overload pressure differs depending on each arm. Therefore, the overload detection device 50 is set with an upper limit set pressure for judging that each arm 1, 2, 3, 4 is overloaded and a lower limit set pressure for judging the trajectory control recovery. . When any of the pressures of the hydraulic cylinders 1c, 2c, 3c, 4c detected by the pressure sensors 51 to 58 reaches the upper limit set pressure, the overload detection device 50 outputs a stop signal to the controller 20. Then, when the pressure of the hydraulic cylinder that has reached the upper limit set pressure falls to the lower limit set pressure, a locus control return signal is output to the controller 20.

The controller 20 includes an overload detection device 50.
When the stop signal is input, the electromagnetic proportional directional control valves 22 and 23 for controlling the pressure oils supplied to the hydraulic cylinder 2c that drives the second arm 2 and the hydraulic cylinder 3c that drives the third arm 3, respectively. Pause the flow control command. The electromagnetic proportional directional control valves 22 and 23 are switched to the neutral state, and the pressure oil from the hydraulic source is transferred to the hydraulic cylinder 2c,
It is prevented from being supplied to 3c. As a result, the operation of the articulated arm 130 is stopped. Also, the controller 2
When the locus control return signal is input from the overload detection device 50, the electromagnetic proportional directional control valve 22,
The flow rate control command to 23 is restored. Such control can be controlled using, for example, switches S1 and S2 that are closed during normal trajectory control, are opened by a stop signal from the controller 20, and are closed by a trajectory control return signal.

A signal indicating whether or not the trajectory deviation prevention control is selected by the on / off switch 60 is input to the overload detection device 50 and then sent to the operation display device 62. The operation display device 62 notifies the operator or the like by voice or a lamp that the trajectory deviation prevention control is in operation.
When the overload detection device 50 determines that one of the hydraulic cylinders has reached the upper limit set pressure, the alarm device 61 issues an alarm by voice or lamp.

As described above, the hydraulic cylinders 1c, 2
When any one of pressures c, 3c, and 4c reaches the upper limit set pressure and becomes an overload state, the stop signal is received and the articulated arm 13 is received.
0 operation is stopped. If the operation of the vibro hammer is continued while stopped, the vibration force of the vibro hammer can reduce the frictional force between the sheet pile and the ground that are in close contact with each other. As a result, the load on the articulated arm 130 is reduced, and the pressure of the hydraulic cylinder that has reached the upper limit set pressure is reduced. When the overload detection device 50 detects that the pressure of the hydraulic cylinder has decreased to the lower limit set pressure by the pressure sensors 51 to 58,
A trajectory control return signal is output to the controller 20. Upon receiving the trajectory control return signal, the trajectory control operation of the articulated arm 130 is restarted.

Here, the upper limit set pressure stored in the overload detection device 50 is set to the respective hydraulic cylinders 1c, 2c, 3c,
The pressure is set to be equivalent to the cracking pressure of an overload relief valve (not shown) provided at 4c. This prevents the hydraulic pressure of the hydraulic cylinder from being relieved by the relief valve when an overload occurs, and prevents the hydraulic cylinder from undesirably expanding and contracting. On the other hand, the lower limit set pressure stored in the overload detection device 50 is set to a pressure at which the cylinder pressure does not cause hunting between the upper limit set pressure and the lower limit set pressure.

The trajectory deviation prevention control processing procedure of the articulated arm 130 described above will be described with reference to the flowcharts shown in FIGS. Although the processing procedure of the trajectory control of the multi-joint arm 130 is also described in the flowchart of FIG. 4, the trajectory control is publicly known, and a detailed description thereof will be omitted.

The flowchart of FIG. 3 shows the processing procedure of the trajectory deviation prevention control program in the overload detection device 50. First, in step S1, it is determined whether the trajectory deviation prevention control on / off switch 60 is turned on. If it is determined in step S1 that the on / off switch 60 is turned on, the operation display device 62 is determined in step S2.
Informs the operator that the trajectory deviation prevention control is in operation. On the other hand, if the on / off switch 60 is off, the display by the operation display device 62 is turned off in step S11. In step S3, the pressure sensors 51-5
The pressure signals of the hydraulic cylinders 1c, 2c, 3c, 4c detected at 8 are input.

In step S4, the upper limit set pressure of each hydraulic cylinder previously stored in the overload detection device 50 is compared with the detected pressure of each hydraulic cylinder. Step S
If it is determined in step 4 that the pressure of any of the hydraulic cylinders exceeds the upper limit set pressure, the process proceeds to step S5, and the alarm device 61 issues an alarm. In step S6, a stop signal for stopping the trajectory control operation of the articulated arm 130 is output to the controller 20.

If it is determined in step S4 that the pressure of each hydraulic cylinder has not reached the upper limit set pressure, the process proceeds to step S7. In step S7, the current controller 2
It is determined whether or not the stop signal is output to 0. If it is determined in step S7 that the stop signal is output, it means that one of the hydraulic cylinders exceeds the upper limit set pressure, and the process proceeds to step S8 and step S3.
It is determined whether or not the pressure of each hydraulic cylinder input in step 3 has dropped below the lower limit set pressure. If it is determined in step S8 that the pressure has dropped to the lower limit set pressure, the alarm by the alarm device 61 is stopped (step S9), and a trajectory control return signal is output to the controller 20 in step S10. In addition, when step S7 and step S8 are denied determination, it returns to step S1.

The flowchart of FIG. 4 is based on the controller 2
A processing procedure of a trajectory control of the articulated arm 130 and a trajectory deviation prevention control program at 0 will be described. First, in step S10, it is determined whether the trajectory control lever 21 has been operated. If the trajectory control lever 21 is not operated, the process ends without performing the process. When the trajectory control lever 21 is operated, the process proceeds to step S11, and it is determined whether or not the reference work radius R0 is already set. When the reference work radius R0 is not set, the arm angle detected by the angle detectors 11 to 14 is input in step S12,
In step S13, the reference work radius R0 is calculated. As shown in FIG. 2, a trajectory control target straight line L in which the tip A of the articulated arm 130 is trajectory controlled by the reference work radius R0.
Is set.

In step S14, the speed command value Y'in the working direction is detected from the current operating state of the trajectory control lever 21. Here, either the upper or lower direction along the trajectory control target straight line L is the working direction. At step S15, the current second and third arms 2 and 3 detected by the angle detectors 12 and 13 are detected.
Enter the angle of and the current working radius X4 based on these
Is calculated (step S16).

In step S17, the following (formula 1)
Then, the speed command value X ′ in the correction direction is calculated.

X ′ = K × (R0−X4) × | Y ′ | (K: constant) (Equation 1) If the tip A of the articulated arm 130 does not deviate from the trajectory control target straight line L, correction is made. Direction speed command value X'is 0
Becomes

In step S18, the speed command value X ',
The angular velocities θ2 ′ and θ3 ′ targeted by the second and third arms 2 and 3 are calculated from Y ′ and the angles of the second and third arms so that the tip A moves along the trajectory control target straight line L. .
In step S19, the stroke amount of the hydraulic cylinders 2c and 3c corresponding to the angular velocities θ2 ′ and θ3 ′ is calculated. In step S20, the flow rate supplied to the electromagnetic proportional directional control valves 22, 23 is converted from the stroke amount calculated in step S19, and the electromagnetic proportional directional control valve 22, 23 is converted according to the flow rate.
The PWM current command value output to 23 is calculated (step S21).

In a succeeding step S22, it is determined whether or not a signal relating to the trajectory deviation prevention control is input from the overload detection device 50. If it is determined in step S22 that no signal is input, the trajectory deviation prevention control is not performed. Step S22
When it is determined that the stop signal is input from the overload detection device 50, the switches S1 and S2 are opened to stop the trajectory control of the articulated arm 130 (step S23). If it is determined in step S22 that the trajectory control return signal has been input from the overload detection device 50, the articulated arm 13
The switches S1 and S2 are closed to return the trajectory control of 0 (step S24).

In step S25, PWM is performed based on the determinations in step S22, step S23, and step S24.
Outputs or stops the current command value and switches the electromagnetic proportional directional valve 2
2 and 23 are controlled. By driving the electromagnetic proportional direction switching valves 22 and 23, the pressure oil supplied from the hydraulic source to the hydraulic cylinders 2c and 3c is controlled, and as a result, the multi-joint arm 130 is provided.
Can be controlled.

The above-described processing in the controller 20 is continued while the locus control lever 21 is operated,
The operation ends when the operation of the trajectory control lever 21 is released. At this time, the reference work radius R0 returns to the initial state.

As described above, the trajectory deviation prevention device for a multi-joint arm working machine according to the present invention detects the overload of the multi-joint arm and stops the trajectory control of the multi-joint arm. . As a result, there is no deviation of the tip of the multi-joint arm that occurs when the hydraulic cylinder that drives the multi-joint arm escapes due to overload, that is, the deviation of the position of the front attachment such as the vibro hammer. As a result, it is possible to prevent deterioration of the construction accuracy of the sheet pile or the pile, and further to prevent bending or damage of the sheet pile, the pile, the arm, or the like.

Further, the upper limit set pressure for stopping each hydraulic cylinder is made equivalent to the cracking pressure of the overload relief valve provided in each hydraulic cylinder, and the pressure of the hydraulic cylinder reaches the set pressure of the overload relief valve so that the hydraulic cylinder operates. Stop the hydraulic cylinders before making a runaway. As a result, the posture of the entire multi-joint arm does not collapse and the position of the front attachment such as the vibro hammer does not deviate, so that it is possible to prevent deterioration in the construction accuracy of the sheet pile, the pile, or the like. Further, since the arm posture does not collapse, when the hydraulic cylinder returns from the overloaded state to the safe state, the trajectory control can be restarted without remaking the arm posture.

Further, when the pressure of the hydraulic cylinder falls below the lower limit set pressure, the trajectory control is restored, so that the trajectory control can be restored after the friction between the sheet pile or the pile and the ground is reduced. Furthermore, since the trajectory control is automatically restarted instead of being manually performed, operability is good. Further, since the on / off switch for selecting whether or not to operate the trajectory deviation prevention control is provided, any one can be selected according to the operator's preference.

In the above-described embodiment,
When the pressure of any one of the hydraulic cylinders 1c, 2c, 3c, and 4c reaches the upper limit set pressure, the trajectory control operation of the articulated arm 130 is stopped. However, if the frictional force between the sheet pile and the ground is reduced due to the vibration of the vibro hammer or the like, and the pressure of the hydraulic cylinder drops to the lower limit set pressure, the speed may be reduced. Also. Although the trajectory control target straight line L of the articulated arm 130 extends in the vertical direction as shown in FIG. 2, it may be in the horizontal direction or any direction.

The multi-joint arm does not have to be composed of four arms as long as it can control at least two hydraulic cylinders for driving the multi-joint arm for trajectory control. For example, it is composed of three arms. May be done.
Also, a switch is used to stop the PWM current command to the electromagnetic proportional directional control valve, but the controller sets a flag by a stop signal from the overload detection device, and stops the PWM current command when the flag is generated. You may allow it.

In the above-described embodiment, the second arm 2 is used as the first and second arms whose locus is controlled,
Although the third arm 3 is used, the first or fourth arm 1, 4
May be used. In addition, the pressure sensor 5 as a load detector
1 to 58 are used, the overload detection device 50 is used as the determination device, and the controller 20 is used as the control device, but their configurations are not limited to the embodiments.

[0042]

As described above, the load applied to the hydraulic cylinder that drives the trajectory-controlled articulated arm is detected, and when the load applied to the hydraulic cylinder exceeds the upper limit set value, the trajectory control is stopped or decelerated. I chose As a result, it is possible to prevent the trajectory from being deviated due to the multi-joint arm being overloaded and the hydraulic cylinder running away.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a trajectory deviation prevention device for an articulated arm working machine according to an embodiment of the present invention.

FIG. 2 is a side view of the articulated arm working machine without the front attachment.

FIG. 3 is a flowchart showing a processing procedure of trajectory deviation prevention control in the overload detection device 50.

FIG. 4 is a flowchart showing a processing procedure of trajectory control and trajectory deviation prevention control in the controller 20.

[Explanation of symbols]

1-4: 1st-4th arms 1c-4c: hydraulic cylinder 11-14: Angle detector 20: Controller 21: Trajectory control lever 22, 23: Electromagnetic proportional directional control valve 50: Overload detection device 51-58: Pressure sensor 60: On-off switch 61: Alarm device 62: Operation display device

Continued front page    F term (reference) 2D003 AA00 AB03 AB04 AC11 BA02                       BA03 BA07 BB03 BB04 BB07                       BB10 CA02 DA02 DA03 DA04                       DB02 DB04 DC02 FA02                 2D015 GA03 GB04 GB05                 2D050 AA01 AA12 CB32 FF02 FF05                 3C007 AS21 BS10 CS08 CT05 CV08                       CW08 HS01 HS13 JT08 LU03                       MS03 WA17

Claims (4)

[Claims] 1. A locus control target portion of an articulated arm having at least first and second arms is a first and a second.
In a multi-joint arm working machine whose locus is controlled to move along a predetermined locus by the hydraulic cylinder, the load detector for detecting the load of the first and second hydraulic cylinders, and the load detector. A determination device for determining whether or not the detected load of the first or second hydraulic cylinder exceeds a set value, and the load of the first or second hydraulic cylinder exceeds the set value by the determination device. When it is determined that
A trajectory deviation prevention device for an articulated arm working machine, comprising: a controller for stopping or decelerating trajectory control by the first and second hydraulic cylinders. 2. The trajectory deviation prevention device for an articulated arm according to claim 1, wherein the set value includes an upper limit set value and a lower limit set value, and the control device is configured to determine the first or the first by the determination device. When it is determined that the load of the second hydraulic cylinder exceeds the upper limit set pressure, it is determined that the locus control by the first and second hydraulic cylinders is stopped or decelerated and the lower limit set value is exceeded. In this case, a trajectory deviation prevention device for an articulated arm working machine, which recovers trajectory control during stop or deceleration. 3. A trajectory deviation prevention device for an articulated arm according to claim 1 or 2, wherein a set value of a load for stopping or decelerating trajectory control of the first hydraulic cylinder or the second hydraulic cylinder. Are differently set for the first and second hydraulic cylinders, respectively, and a trajectory deviation prevention device for an articulated arm working machine. 4. An articulated arm working machine comprising the trajectory deviation prevention device for the articulated arm working machine according to any one of claims 1 to 3.