JPH0819973A - Two-articulated arm mechanism provided with two articlar simultaneous driving source and its motion control method - Google Patents

Abstract

PURPOSE:To precisely and easily control a position, force, and rigidity of a load point formed at the tip of the second arm independently in a two- articulated arm mechanism. CONSTITUTION:In a two-articulated arm mechanism, in which the rear end of the second arm is pivoted rotationally at the tip of the first arm whose rear end is rotationally pivoted in a base 3 while the tip of the second arm 5 is set as a load point, two driving sources 9, 10 individually applying rotational force to both arms are connected to the first arm and the second arm 5 respectively, so that the first arm and the second arm 5 are rotated independently in their respective pivot shafts, and the arm mechanism is operated to be extended or to be bent. A single driving source 11 working on both arms simultaneously is connected to both members 3, 5, and the respective driving sources 9, 10, 11 are driven at the same time, so that a load part 8 at the tip of the second arm 5 is positioned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to robots and manipulators that require rigidity control in the operation of advancing and retracting various loads in a posture in which they are supported by raising them.
The present invention relates to a two-joint arm mechanism suitable for application to an arm of a power shovel or the like, and a method of controlling the operation thereof.

[0002]

2. Description of the Related Art Conventionally, robots, manipulators,
Or, in the arm of a power shovel, etc., two joint arms
Various types have been proposed for the one using the moving mechanism.
For example, as shown schematically in FIGS. 5 and 6, the rear end is the axis P1.
The rear end of the second arm A2 is pivotally attached to the tip of the first arm A1 pivotally attached by means of the shaft P2, and the load portion W for the load by a grip or bucket is attached to the tip of the second arm A2. On the other hand, the first arm A1 and the second arm A2 are connected to the axis P of the pivot point.
There is one that can turn in any direction in 1 and P2. The directions of the axes P1 and P2 are either horizontal or vertical. Therefore, depending on the directions of the axes P1 and P2, the arm mechanism is deformed in the vertical plane or in the horizontal plane.

The example illustrated in FIG. 6 includes two arms A1 and
A motor M is attached to each of the axes P1 and P2 as a drive mechanism for rotating A2 in any direction about the pivot points P1 and P2.
1 and M2 are provided, and the forward and reverse rotational forces of the motors M1 and M2 are selectively transmitted to the arms A1 and A2,
Rotate both arms A1 and A2 in an arbitrary direction, and load part W1
The position of can be changed freely.

The one illustrated in FIG. 5 has two arms.
Telescopic actuator C such as hydraulic cylinder for A1 and A2
1 and C2 are erected, and the arms A1 and A2 are connected to the axes P1 and P2 of their pivot points by the expansion and contraction motions of the actuators C1 and C2 respectively.
In this case, the load portion W2 such as a bucket at the tip is caused to perform work such as excavation. Incidentally, C3 is an actuator for controlling the attitude of the load section W2.

However, in the known two-joint arm mechanism as described above, the second arm is connected to the rear end of the first arm A1.
Independent control of the position of the load W1 or W2 at the tip of the frame A2 and the force and rigidity is extremely difficult in terms of control theory, and therefore is currently controlled approximately.

However, in the well-known two-joint arm mechanism, when the position, force, and rigidity of the load portion W are approximately controlled, when the load supported by the load portion W is large,
There is a problem that it is difficult to perform accurate and quick positioning control. For this reason, the current robot, manipulator, or arm of a power shovel has an output and a braking force which can be said to be excessive in terms of the load allowed in the load section W in the drive source, and the control thereof. Is used. However, such a power source and a braking mechanism for the excessive output and the braking force are provided by an arm of a power shovel, a robot, or
Incorporation into a manipulator is wasteful not only in terms of structure but also in terms of economy, and it is difficult to operate and requires a large capacity controller.

[0007]

Therefore, the problem to be solved by the present invention is to determine the position, force and rigidity of the load point formed at the tip of the second arm in the two-joint arm mechanism. It is an object of the present invention to provide a two-joint arm mechanism equipped with a two-joint simultaneous drive source that can be independently controlled accurately and easily and a control method thereof.

[0008]

The structure of the present invention, which has been made for the purpose of solving the above-mentioned problems, has a basic basis.
The rear end of the second arm is rotatably attached to the front end of the first arm whose rear end is rotatably supported by the second arm.
In a two-joint arm mechanism using the tip of the arm as a load point, the first arm and the second arm are independently rotated about their respective pivot axes and extended to this arm mechanism. In order to perform a motion or a bending motion, two drive sources that independently apply a rotational force to the both arms are provided respectively connected to the first arm and the second arm, and One drive source acting on both arms at the same time is connected so as to be straddled between the base and the second arm, and the drive sources are driven at the same time. And the load portion at the tip of the second arm is advanced or retracted with respect to the rear end of the first arm to position the load point at the tip of the second arm. Is.

Further, in the construction of the method for controlling the operation of the arm mechanism, the rear end of the first arm is rotatably supported at the base, and the rear end of the first arm is connected to the rear end of the second arm. In a two-joint arm mechanism in which the end is rotatably pivoted and the tip of the second arm is a load point, the first arm and the second arm are pivotally pivoted respectively. In order to rotate the arm mechanism independently of each other and to cause the arm mechanism to perform an extension motion or a bending motion, two drive sources that independently apply a rotational force to the both arms are provided with the first arm and the second arm. It is connected to the arm, respectively, and one driving source that acts simultaneously on the rotating and rotating directions of both arms is provided between the base and the second arm. When the two drive arms are connected to each other and the two joint arm mechanisms are extended or bent at the same time by driving the respective drive sources at the same time, the respective driving forces transmitted to the both arms as rotational forces. By controlling the difference between the output that is cooperative with respect to the extension or flexion motion of the entire two-joint arm mechanism and the output that is antagonistic, and the sum of both outputs The position of the load point, the force of the load point, and the rigidity of the load point are controlled respectively.

[0010]

A two-joint structure in which the two arm arms, the first arm and the second arm, are rotated independently of each other so that the entire arm mechanism can be extended or bent. In the arm mechanism, in order to extend or bend the arm mechanism, two drive sources that act in cooperation with the rotational movement of the respective arms and one that acts antagonistically. By providing a drive source and operating each drive source at the same time, the second
The position and the force and rigidity of the load portion formed at the tip of the arm are controlled separately.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the arm mechanism of the present invention will be described with reference to FIGS.
This will be described below. In FIG. 1, 1 is a first arm, and a horizontal shaft 2 at a rear end 1a thereof is a bearing 4 of a fixed base 3
It is rotatably and pivotally supported. 5 is the second arm,
A horizontal shaft 6 at its rear end 5a is rotatably attached to a bearing 7 formed at the tip 1b of the first arm 1. 8 is the second
A load part formed by a gripping tool, a bucket, or the like formed at the tip 5b of the arm 5 forms a two-joint arm having the shafts 2 and 6 as joints by the respective members from the first arm to the load part 8. There is.

The two-joint arm is an actuator installed between the intermediate portion of the first arm 1 and the base 3, for example,
The respective movements of the hydraulic cylinder 9 and the hydraulic cylinder 10 installed between the tip side of the first arm 1 and the intermediate portion of the second arm 5 cause the respective arms 1 and 5 to move. It is independently rotatable about its axes 2 and 6 in the clockwise and counterclockwise directions. The structure up to this point is mechanically equivalent to the conventionally known two-joint arm mechanism shown in FIG. Are virtually the same.
In the hydraulic cylinders 9 and 10, 9a and 10a are piston rods, 9b and 10b are cylinder bodies, 9c and 10c are pistons, and 9d, 10d, 9e and 10e are pressure oil supply / discharge ports.

However, with this two-joint arm mechanism, the force and rigidity of the load portion 8 provided at the tip of the second arm 5 as seen from the base 3 can be accurately and quickly controlled. What cannot be done is as described above.

Therefore, in the arm mechanism of the present invention, by providing a hydraulic cylinder as one drive source that acts on the arms 1 and 5 at the same time when the arms 1 and 5 rotate, The force and the rigidity of the load portion 8 with respect to the base 3 can be controlled separately from those of the first arm 1 and the second arm 5.

That is, here, a hydraulic cylinder 11 is provided between the rear end side of the second arm 5 and the base 3 to connect the piston rod 11 thereof.
It is provided by connecting the tip of a to the extended rear end of a connecting rod 11b 'formed by extending from the rear end of the cylinder body 11b, and when the arm 1 or 5 or both of them rotate, the cylinder 11 The pressure P1 of the pressure oil supplied to and discharged from the pressure oil supply / discharge ports 11d and 11e of the cylinder 11 against the force generated by the rotation of the arms 1 and 5 acting on the front and rear surfaces of the piston 11c.
Or, it controls P2.

However, the pressure oil is supplied to the pressure oil supply / discharge ports 9d and 9e of the cylinders 9 and 10 and the pressure oil supply / discharge ports 10d and 10e, respectively. Ten
Moves the rods 9a and 10a forward or backward, and rotates the arms 1 and 5 clockwise or counterclockwise. Here, for convenience of description, the pressure oil is supplied to the pressure oil supply / discharge ports 9d, 10d so that the rods 9a, 10a of both cylinders 9, 10 advance together, or the cylinder bodies 9b, 10b retreat. Both arms 1 and 5 are assumed to be rotated counterclockwise (on the side of the solid arrow).

By the rotation of both arms 1 and 5, the cylinder 11 receives a force on the side where the piston 11c retreats, but in the present invention, when the both arms 1 and 5 rotate, the pressure oil of the cylinder 11 is changed. By supplying pressure oil of pressures P1 and P2 to the supply / discharge ports 11d, 11e, the output of the cylinder 11 acts on both arms 1, 5 at the same time.

Here, the pressure P1 of the pressure oil applied to the front surface of the piston 11c becomes a force that cooperates with the rotational force of the arms 1 and 5, and the pressure P2 of the pressure oil applied to the back surface of the piston 11c opposes it. Therefore, if the pressure has a relation of P1> P2, the arms 1 and 5 rotate as they are. However, the difference between the two pressures P2-P1
Is equal to the force applied to the piston 11c by the rotation of the arms 1 and 5, the rotation of the arms 1 and 5 stops, and when the pressure difference becomes large, the arms 1 and 5 reverse.

The present invention utilizes the fact that one cylinder 11 simultaneously acts on the rotational force of each of the two arms 1 and 5, and the load portion 8 at the tip of the second arm 5 is utilized. This cylinder is used to control the force and rigidity of the base 3 against the base 3.
Pressures P1 and P2 of pressure oil supplied to the pressure oil supply / discharge ports 11d and 11e of 11
I controlled the size of.

FIG. 2 is a conceptual side view of the two-joint arm mechanism of the present invention of FIG. 1 applied to a so-called power shovel. In the example of FIG. 2, the base 3 of FIG. 1 is formed on the vehicle body 31 of the power shovel, and the bearing 7 of the first arm 1 and the shaft 6 of the second arm rear end 5a of FIG. The members (arms 1 and 5) for installing and are reversed from the example of FIG. 1, but other configurations are equivalent to the arm mechanism of FIG. In FIG. 2, 32
Reference numeral 8a is a drive source such as a cylinder for holding and deforming the posture of the load portion.

In FIG. 2, the first arm 1 is rotated clockwise by the action of the cylinder 9 and the second arm 5 is rotated counterclockwise by the action of the cylinder 10, whereby both arms are rotated. The arms 1 and 5 are displaced to the positions of the arms 1'and 5'in the figure, and the load portion 8 is displaced to the position of the load portion 8 '. This a
The clockwise rotation of the arm 1 acts on the side of the cylinder 11 that extends it, whereas the counterclockwise rotation of the second arm 5 acts on the side of the cylinder 11 that contracts. Therefore, at this time,
By controlling the pressures P1 and P2 applied to the front and rear of the piston 11c of the cylinder 11, the output of this cylinder 11 is made to act on the side cooperating with the rotation of the arms 1 and 5, or on the side which opposes. Therefore, the position, the force, and the rigidity of the tip of the second arm 5 with respect to the main body 31 of the load portion 8 can be controlled. In FIG. 2, 1 ", 5", and 8 "indicate the positions of the respective members 1, 5, 8 in another example in which the first arm 1, the second arm 5, and the load portion 8 are displaced. It is shown.

Since the two-joint arm mechanism of the present invention can be configured as the arm mechanism shown in FIGS. 3 and 4, the embodiment shown in FIGS. 3 and 4 will be described below. 3 and 4, the same symbols as those in FIGS. 1 and 2 indicate the same members.

3 and 4, reference numeral 1 is a first arm, the rear end of which is integrated with the shaft 2 and which is attached to the shaft 2 and has a pinion 21a formed on the outer periphery thereof. The rotating body 21 is provided as a rotational force transmitting portion, and the first arm
Since it is integrated with the frame 1, it is rotatably supported by the bearing 4 provided on the base 3 about the shaft 2.

A tip base 1c integral with the first arm 1 is formed at the tip of the first arm 1, and a rear end 5a of the second arm 5 is integrally fixed to the rear end of the shaft. At 6, a bearing 7 at the tip of the first arm 1 is rotatably attached.
A rotating body 61 having a pinion 61a formed on the outer periphery is integrally provided on the shaft 6 as a rotational force transmitting portion and is integrated with the second arm 5. 8 is the tip of the second arm 5.
The load portion is formed by a load supporting means such as a grip and a hook provided on 5b. The two arms 1 and 5 are connected at their front and rear ends, and their rear ends 1a and 5a are independently rotatably supported via shafts 2 and 6, respectively. The arm mechanism comprises pinions 21a, 6 of rotating bodies 21, 61 which are integral with both arms 1, 5 via shafts 2, 6, respectively.
1a can be independently rotated clockwise or counterclockwise by applying a rotational force to each.

In the arm mechanism of the present invention shown in FIGS. 3 and 4, the piston rods 9a and 10a are attached to both the pinions 21a and 61a.
By disposing, for example, hydraulic cylinders 9 and 10 provided with racks 12 and 13 on the front end side of each of them by engaging the respective racks 12 and 13 with each other, the pinions 21a and 61a can be independently moved in the forward and reverse directions. It is arranged as a drive source for transmitting the rotational force of. In the illustrated example, the cylinder 9 is attached to the base 3 and the cylinder 10 is attached to the first arm 1, respectively, and the cylinders 9 and 10 advance and retract the respective piston rods 9a and 10a. By operating the pinion 21
The first arm 1 and the second arm 5 can be rotated independently of each other by rotating the a and 61a clockwise or counterclockwise, respectively. There is.

Here, 11 is a drive source by a hydraulic cylinder, and a rack 14 provided at the tip side of the piston rod 11a thereof.
Is engaged with the pinion 61a 'of the rotating body 61' which is integrated with the second arm 5 through the shaft 6 on the opposite side of the rack 13 from which the shaft 6 is sandwiched, and is integrally formed with the cylinder body 11b to form a cylinder. A rack 15 extending and formed on the rear side of the main body 11b
On a pinion 21a 'of a rotating body 21' which is loosely inserted in the shaft 2 of the first arm 1 and fixed on the base 3, on the side opposite to the rack 12 with the shaft 2 interposed. It is installed between the two pinions 61a ', 21a' so that they can be engaged with each other and can act simultaneously on the two pinions 61a ', 21a'. Although the erection holding means of the cylinder 11 is not shown,
The cylinder 11 is to be supported by an appropriate means that can be freely supported in the forward / backward direction.

The cylinders 9 and 10 of the drive source for independently applying the rotational force to the respective arms 1 and 5 are pistons thereof.
By supplying pressure oil to either the front surface side or the rear surface side of 9c, 10c, the racks 12, 13 are independently advanced and retracted, and the pinions 21a in which the racks 12, 13 mesh with each other. 61a
Here, as an example, since the rotational forces in opposite directions are applied to each other, the both arms 1 and 5 rotate integrally with the respective pinions 21a and 61a in the same direction.

On the other hand, in the cylinder 11, which is one driving source that acts on the two pinions 61a 'and 21a' at the same time, the pressure oil is supplied to the pressure oil supply / discharge ports 11e and 11d while adjusting the supply pressure. As a result, the rack 14 integrated with the piston rod 11a and the rack 15 integrated with the cylinder body 11b are operated so as to be relatively separated from each other, approach each other, or fixed. To be By the action of the cylinder 11, the rotation on the side that counteracts the rotational force of the arms given to the pinions 21a and 61a by the outputs of the cylinders 9 and 10 of the drive source, or on the side that cooperates with them. A force is applied to the arm 1, through the pinion 21a 'and the pinion 61a'.
5 are given at the same time. Pinion by the cylinder 11
The forces simultaneously applied to the arms 1 and 5 via 21a 'and the pinion 61a' are independently applied to the arms 1 and 5 by the cylinders 9 and 10 via the pinions 21a and 61a, respectively. The force equal to the rotational force is controlled as the maximum value.

That is, in the above example, when the first arm 1 is rotated counterclockwise by the backward movement of the rack 12 and at the same time the second arm 5 is rotated clockwise by the forward movement of the rack 13, the cylinder 1 is rotated. Pressure oil P1 and pressure oil P2, whose pressures are controlled, are supplied to the pressure oil supply / discharge ports 11d and 11e of 11, respectively. Here, if the pressure of the pressure oil is P2> P1, the rack 14 and the rack 15 advance in the directions in which they are separated from each other, whereby the advance of the rack 14 is given to the rotating body 61 by the cylinder 10. It acts as a force that opposes the rotational force, and the advance of the rack 15 acts as a force that cooperates with the rotating body 21. Pressure is P2 <
P1 has the opposite effect.

In the arm mechanism of the present invention, the first arm 1 outputs the output from the cylinder 9 to the base 3 to the arm 1 concerned.
The rotational force and rigidity of the tip of the robot are controlled, and the second arm 5
The rotational force and rigidity of the tip of the arm 5 at the tip of the first arm 1 are controlled by the output of the cylinder 10.
However, this alone cannot control the force and rigidity of the load portion 8 formed at the tip of the second arm 5 with respect to the base 3. Therefore, in the present invention, the load portion 8 of both arms 1 and 5 cannot be controlled. A cylinder 11 that acts on both arms 1 and 5 at the same time during rotation is provided so that the force and rigidity of the load portion 8 on the base 3 at the tip of the second arm 5 can be controlled.

As described above, the two-joint arm mechanism of the present invention has two independent drive sources 9 and 9 for each arm 1 and 5.
By the output of 10, the first and second arms 1 and 5 are independently rotated to cause the arm mechanism as a whole to perform flexion and extension motions, while at the same time, to both arms 1 and 5. By controlling the output of one driving source 11 that acts at the same time, the position of the load portion 8 formed at the tip of the second arm 5 with respect to the base 3 is controlled when the arm mechanism bends and extends. The force and the rigidity can be controlled separately from the control of the rotational force and the rigidity of the first arm 1 and the second arm 5.

[0032]

The present invention is as described above. In the two-joint arm mechanism, since the load point formed at the tip of the second arm is advanced and retracted, the rotational force is independently applied to each arm. And two different driving forces that give output to the two driving sources and act on the rotations of the two arms by the outputs of the two driving sources.
Since one drive source applied to both arms at the same time is provided across both arms so that each drive source can be driven and controlled simultaneously, the base of the load part formed at the tip of the second arm is fixed. A special effect that cannot be achieved by the conventional two-joint arm mechanism that the force and rigidity for movement and positioning with respect to the system can be controlled separately from the first arm and the second arm. Is obtained.

[Brief description of drawings]

FIG. 1 is a side view of an example of an arm mechanism of the present invention.

FIG. 2 is a side view of an example in which the arm mechanism of FIG. 1 is applied to a power shovel.

FIG. 3 is a plan view of another example of the arm mechanism of the present invention.

4 is a side view of the arm mechanism shown in FIG.

FIG. 5 is a side view of an example of a known arm mechanism.

FIG. 6 is a plan view of another example of the known arm mechanism.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 1st arm 2 Rotation shaft of 1st arm 3 Base 4 Bearing 5 2nd arm 7 Rotation shaft of 2nd arm 8 Load part 9 For rotation drive of 1st arm Hydraulic Cylinder 10 Hydraulic Cylinder for Rotating and Driving the Second Arm 11 Hydraulic Cylinder Acting on Both First and Second Arms at the Same Time

Claims (3)

[Claims] 1. A rear end of a second arm is rotatably attached to a front end of a first arm whose rear end is rotatably supported by a base base so as to rotate. The load point is the tip of the arm 2
In the joint arm mechanism, the first arm and the second arm are independently rotated about their respective pivot axes to allow the arm mechanism to perform an extension motion or a bending motion. Two drive sources for independently applying a rotational force to both arms are provided respectively connected to the first arm and the second arm, and
One drive source acting on both arms at the same time is applied to the beam.
And the second arm, the two driving arms are driven at the same time to swivel the two arms so that the load portion at the tip of the second arm is located at the first position. A two-joint arm mechanism equipped with a two-joint simultaneous drive source, characterized in that the load point at the tip of the second arm is positioned by advancing or retracting with respect to the rear end of the arm. 2. A drive mechanism for rotating the first arm and the second arm, respectively, has a rotational force transmitting portion such as a sprocket integrated with each arm on the rotation center side of each arm. One drive source that is formed on each of the two rotary force transmitting portions and that is connected to each of the rotary force transmitting portions independently of each other, while simultaneously applying a rotary force to the two rotary force transmitting portions. 2. A two-joint arm drive mechanism equipped with a two-joint simultaneous drive source according to claim 1, wherein said two arms are connected to each other by straddling between the base and the second arm in the vicinity of the center of rotation of both arms. 3. A rear end of a second arm is rotatably attached to a front end of a first arm whose rear end is rotatably supported on a base, and the second arm is rotatably attached. In a two-joint arm mechanism with the tip of the arm as a load point, the first arm and the second arm are independently rotated about their respective pivot axes, and the arm mechanism is extended. Alternatively, in order to perform a bending operation, two drive sources that independently apply a rotational force to the both arms are provided respectively connected to the first arm and the second arm, and the two drive sources are connected to each other. A
One drive source that simultaneously acts on the rotation direction of the frame is connected between the base and the second arm so that the drive sources are driven simultaneously to form the two-joint arm. When the entire arm mechanism is extended or bent, among the outputs of the respective driving sources transmitted as rotational force to the both arms, the two joint arm mechanism cooperates with the extension or bending operation of the entire arm mechanism. The position of the load point, the force of the load point, and the rigidity of the load point are respectively controlled by controlling the difference between the output that becomes and the output that becomes antagonistic, and the sum of the both outputs. And a method for controlling the operation of a two-joint arm mechanism equipped with a two-joint simultaneous drive source.