JP3375202B2 - Two-joint arm mechanism equipped with two-joint simultaneous drive source and operation control method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to robots, manipulators, power shovel arms, and the like which require rigidity control in the operation of advancing and retracting various loads in a posture of supporting them and positioning them. And a preferred two-joint arm mechanism and its operation control method.

[0002]

2. Description of the Related Art Conventionally, robots, manipulators,
Alternatively, various arms such as power shovels that use a two-joint arm mechanism have been proposed.
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 a load portion W for loading by a grip or a bucket is provided at the tip of the second arm A2. Connect one arm A1 and the second arm A2 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 example shown in FIG. 5 has two arms.
Telescopic actuator C such as a 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 position and force and rigidity of the load portion W1 or W2 at the tip of the second arm A2 are independent of the rear end of the first arm A1. Since control is extremely difficult in terms of control theory, the present situation is that control is performed approximately.

However, in the 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. Therefore, in the current robot, manipulator, or arm of a power shovel, a drive source that has an output and a braking force that are excessive in terms of the load allowed in the load section W in the drive source and that can be controlled Is used. However, such an excessive output, a driving source of braking force, a braking mechanism, a power shovel arm, 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 it requires a large capacity controller.

[0007]

SUMMARY OF THE INVENTION Therefore, the problem to be solved by the present invention is that in a two-joint arm mechanism, the position of the load point formed at the tip of the second arm and the force and rigidity are independent and accurate. And to provide a two-joint arm mechanism equipped with a two-joint simultaneous drive source that can be easily controlled, and a control method thereof.

[0008]

The structure of the present invention made for the purpose of solving the above-mentioned problems is such that a second arm is provided at the tip of a first arm rotatably supporting a rear end of a base as a base. In a two-joint arm mechanism in which a rear end of an arm is rotatably pivoted and a tip end of the second arm is a load point, the first arm and the second arm are independently provided in respective pivot axes. In order to rotate and cause the arm mechanism to perform an extension operation or 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 One drive source that acts on both arms at the same time is connected so as to straddle between the base and the second arm to drive the drive sources for the first arm and the second arm.
When moving the first and second arms to rotate,
The output of the drive source that acts on both arms at the same time is
Control the side that counteracts the rotation of the arm and the second arm
By control, the load point of the controls the rotation of the arms the second arm tip with is advanced or retracted relative to the rear end of the first arm, the load point of the second arm tip
It is characterized in that the positioning is performed.

Further, in the construction of the method for controlling the operation of the arm mechanism, 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 base. In a two-joint arm mechanism using the tip of the second arm as a load point, the first arm and the second arm are independently rotated about their respective pivot axes, and the extension mechanism or the bending mechanism is applied to the arm mechanism. In order to perform the above-mentioned operation, two drive sources that independently apply a rotational force to the both arms are connected to the first arm and the second arm, respectively, and act simultaneously on the rotation direction of the both arms. One driving source is connected to the base and the second arm so as to be straddled between the base and the second arm, and when the driving sources are simultaneously driven to extend or bend the entire two-joint arm mechanism, the two rotating arms rotate. Each drive transmitted as force By controlling the difference between the output that is cooperative with respect to the extension or flexion movement of the entire two-joint arm mechanism and the output that is antagonistic, and the sum of both outputs, It is characterized in that the position of the load point, the force of the load point, and the rigidity of the load point are individually controlled.

[0010]

In the two-joint arm mechanism in which the two arms, the first arm and the second arm, are independently rotated to extend or bend the entire arm mechanism, this arm mechanism is used. In order to extend or bend, two drive sources that act cooperatively with respect to the rotational movement of each arm and one drive source that acts antagonistically are provided, and each drive source is actuated at the same time. Thus, the position, force, and rigidity of the load portion formed at the tip of the second arm are separately controlled.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the arm mechanism of the present invention will be described with reference to FIGS.
Will be described. In FIG. 1, reference numeral 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. Reference numeral 8 is a load portion formed by a gripper, a bucket, or the like formed on the tip 5b of the second arm 5, and each member from the first arm to the load portion 8 forms a two-joint arm having shafts 2 and 6 as joints. 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,
By the forward and backward 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, the respective arms 1 and 5 independently move their shafts 2. , 6 can be rotated clockwise and counterclockwise, and the configuration up to this point is mechanically equivalent and substantially the same as the conventionally known two-joint arm mechanism shown in FIG.
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, as described above, with this two-joint arm mechanism, the force and rigidity of the load portion 8 provided at the tip of the second arm 5 viewed from the base 3 cannot be controlled accurately and quickly. That's right.

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

That is, here, the hydraulic cylinder 11 is provided between the rear end side of the second arm 5 and the base 3 and the piston rod 11 thereof is provided.
It is provided by connecting the tip of a and the extended rear end of a connecting rod 11b 'formed by extending from the rear end of the cylinder body 11b, and when both or one of the arms 1 and 5 rotates, the piston in this 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 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, 10a forward or backward, and rotates the arms 1, 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. It is assumed that both arms 1 and 5 are rotated counterclockwise (on the side of the solid arrow).

The cylinder 11 receives a force on the side where the piston 11c retracts due to the rotation of the arms 1 and 5, but in the present invention, the pressure oil supply / discharge port 11d of the cylinder 11 is rotated when the arms 1 and 5 rotate. , 11e are supplied with pressure oil of pressures P1 and P2, so that the output of the cylinder 11 acts on both arms 1 and 5 at the same time.

Here, the pressure P1 of the pressure oil applied to the front surface of the piston 11c serves as 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 serves as an antagonistic force. Therefore, if the pressure is in the 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 is stopped, and when the pressure difference becomes large, the arms 1 and 5 are reversed.

The present invention utilizes the fact that the one cylinder 11 simultaneously acts on the rotational force of each of the two arms 1 and 5, and makes use of the fact that the tip of the second arm 5 acts on the base 3 of the load section 8. This one cylinder to control force and stiffness
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 in which the two-joint arm mechanism of the present invention of FIG. 1 is 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. 1, 5) is the reverse of the example of FIG. 1, but other configurations are equivalent to the arm mechanism of FIG. In FIG. 2, 32
Is a crawler, and 8a is a drive source such as a cylinder for holding and deforming the posture of the load portion.

In FIG. 2, the action of the cylinder 9 causes the first arm 1 to rotate in the clockwise direction, and the action of the cylinder 10 causes the second arm 5 to rotate in the counterclockwise direction. The load 8 is displaced to the positions of the arms 1'and 5'in the figure, and to the position of the load 8 '. The clockwise rotation of the arm 1 acts on the side of the cylinder 11 that extends it, while 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, it is possible to cause the output of the cylinder 11 to act on the side cooperating with the rotation of the arms 1 and 5, or on the opposing side. Therefore, the position, force, and 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. is there.

Since the two-joint arm mechanism of the present invention can be constructed as the arm mechanism shown in FIGS. 3 and 4, the embodiment of 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.

In FIGS. 3 and 4, reference numeral 1 denotes 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. 21 is provided as a rotational force transmission portion and is integrated with the first arm 1, so that it is rotatably supported by a bearing 4 provided on a 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 attached to the rear end of the shaft 6 which is integrally fixed and erected. It is rotatably attached to a bearing 7 at the tip of the arm 1.
A rotating body 61 having a pinion 61a formed on the outer periphery is integrally provided as a rotational force transmitting portion on the shaft 6 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. A two-joint arm mechanism in which the two arms 1 and 5 are connected at the front and rear ends, and the rear ends 1a and 5a are independently rotatably supported via shafts 2 and 6, respectively. Is a pinion 21a, 6 of the rotating body 21, 61 integrated 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 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 so that the cylinders 9 and 10 actuate the respective piston rods 9a and 10a in forward and backward directions. By the pinion 21
The a and 61a can be rotated clockwise or counterclockwise in either direction, and the first arm 1 and the second arm 5 can be independently rotated.

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 via 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 the cylinder body 11b. Rack 15 extended to the rear side of
Is loosely inserted into the shaft 2 of the first arm 1 and is engaged with the pinion 21a 'of the rotary body 21' fixed on the base 3 on the opposite side of the rack 12 from the shaft 2. The pinions 61a 'and 21a' are provided so as to be able to act simultaneously on both pinions 61a 'and 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 that independently apply the rotational force to the arms 1 and 5 are pistons of those pistons.
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, with which the racks 12, 13 are meshed, 61a
Here, as an example here, since rotational forces in opposite directions are applied to each other, both arms 1 and 5 rotate in the same direction integrally with the respective pinions 21a and 61a.

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 Due to the action of the cylinder 11, the rotational force on the side that counteracts the rotational force of the arm that is given to the pinions 21a and 61a by the output of the cylinders 9 and 10 of the drive source, or the rotational force on the cooperating side, respectively, , The arm 1 through the pinion 21a ′ and the pinion 61a ′.
5 are given at the same time. Pinion by the cylinder 11
The force simultaneously applied to the arms 1 and 5 via 21a 'and the pinion 61a' is equal to the rotational force independently applied to the arms 1 and 5 by the cylinders 9 and 10 via the pinions 21a and 61a, respectively. The force is controlled as the maximum value.

That is, in the above-mentioned example, when the first arm 1 rotates counterclockwise as the rack 12 retreats, and at the same time the second arm 5 rotates clockwise as the rack 13 advances, the pressure oil of the cylinder 11 moves. The pressure oil P1 and the pressure oil P2, whose pressures are controlled, are supplied to the supply / discharge ports 11d and 11e, 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 output of the cylinder 9 causes the first arm 1 to move the arm 1 relative to the base 3.
The rotational force and rigidity of the tip of the
The rotational force and rigidity of the tip of the first arm 1 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, when both arms 1, 5 rotate, A cylinder 11 acting simultaneously on 5 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 for each arm 1, 5.
By the output of 10, the first and second arms 1 and 5 are independently rotated to bend and extend the entire arm mechanism, and at the same time, one drive is applied to both arms 1 and 5 at the same time. By controlling the output of the source 11, the position, force, and rigidity of the load portion 8 formed at the tip of the second arm 5 with respect to the base 3 are controlled by the first arm 1 when the arm mechanism bends and extends. The rotational force and the rigidity of the second arm 5 can be controlled separately.

[0032]

The present invention is as described above .
In a two-joint arm mechanism having an arm and a second arm, two drive sources that independently apply a rotational force to each arm in order to advance and retract the load point formed at the tip of the second arm, and the two drive sources One drive source for simultaneously applying another force acting on the rotation of the both arms due to the output of the
The drive source of the two arms is driven to move the first and second arms.
A drive source that acts on both arms at the same time when rotating
Output of the first arm and the second arm
Since it is controlled to the side that opposes to the fixed side, the force and rigidity for moving and positioning the load part formed at the tip of the second arm with respect to the fixed system such as the base are fixed between the first arm and the second arm. It can be controlled separately, which is a special effect that cannot be achieved by the conventional two-joint arm mechanism.

[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.

FIG. 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]

1 1st arm 2 1st arm rotary shaft 3 base 4 bearing 5 2nd arm 7 2nd arm rotary shaft 8 load part 9 hydraulic cylinder for rotary drive of 1st arm 10 hydraulic pressure for rotary drive of 2nd arm Cylinder 11 Hydraulic cylinder that simultaneously acts on both the first and second arms

Claims (3)

(57) [Claims] 1. A rear end of a second arm is rotatably pivotally attached to a tip of a first arm whose rear end is rotatably supported by a base as a base, and the tip of the second arm is a load point. And 2
In the articulated arm mechanism, the first arm and the second arm are independently rotated about their respective pivot axes, and the arm mechanism is caused to perform a stretching operation or a bending operation. And two drive sources for acting on the first arm and the second arm are connected to each other, and
One drive source that acts on both arms at the same time is straddled between the base and the second arm, and is connected to the first arm .
Drive the drive sources of the arm and the second arm, and
When rotating the arm, it acts on both arms simultaneously.
The output of the drive source is used to rotate the first and second arms.
By controlling to the side that cooperates and the side that opposes, the rotation of both arms is controlled to move the load point of the tip of the second arm forward or backward with respect to the rear end of the first arm , and
2 articulated arm mechanism equipped with a second joint simultaneous drive source, characterized in that so as to position the load point of the second arm tip. 2. A drive mechanism for rotating a first arm and a second arm respectively, wherein a rotational force transmitting portion such as a sprocket integrally with each arm is formed on the rotation center side of each arm, and the above-mentioned each Two driving sources that independently apply rotational force to the rotational force transmitting section are connected to each other, and one driving source that simultaneously applies rotational force to the two rotational force transmitting sections is used as the center of rotation of both arms. The two-joint arm mechanism equipped with the two-joint simultaneous drive source according to claim 1, wherein the two-joint simultaneous drive source is connected so as to straddle between the base and the second arm in the vicinity. 3. A rear end of a second arm is rotatably pivotally attached to a front end of a first arm whose rear end is rotatably supported by a base, and the front end of the second arm is a load point. In the articulated arm mechanism, the first arm and the second arm are independently rotated about their respective pivot axes, and the arm mechanism is caused to perform a stretching operation or a bending operation. And two drive sources that act on the first arm and the second arm are respectively connected to the first arm and the second arm, and one drive source that simultaneously acts on the rotation direction of the both arms is provided on the base and the second arm. Of the outputs of the respective drive sources transmitted as a rotational force to the both arms when the two drive arms are simultaneously driven to extend or bend the entire two-joint arm mechanism. , Extension of the two-joint arm mechanism or By controlling the difference between the output that is cooperative with respect to the bending motion and the output that is antagonistic, and the sum of the both outputs, the position of the load point, the force of the load point, and the rigidity of the load point. A method for controlling the operation of a two-joint arm mechanism equipped with a two-joint simultaneous drive source, which is characterized by individually controlling