JPS5850838B2 - Articulated robot drive mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive mechanism for driving an arm mechanism and a hand mechanism of an articulated robot.

Conventionally, as shown in FIG. 1, an arm mechanism connected between a main body 1 of an articulated robot and a hand mechanism 2 consisting of a chuck or the like for grasping an object includes a crank lever 3 and a crank lever 4.
A motor 5 for rotating the crank lever 3 is installed at the connection point between the main body 1 and the crank 3 of the articulated robot, and a motor 5 for rotating the crank lever 3 is installed at the connection point between the crank lever 3 and the crank lever 4. On the other hand, a motor 6 for rotating the crank lever 4 is provided, and the connection point between the crank lever 4 and the hand mechanism 2 is provided with a motor 6 for rotating the crank lever 4.
A motor 7 for rotating the hand mechanism 2 relative to the hand mechanism 2 is provided.

However, in this type of arm mechanism, a motor with considerable weight is placed at the moving end of the crank lever, so
The inertial force of the crank lever becomes large, making it impossible to quickly control the posture and position of the hand mechanism, and the disadvantage is that it induces vibration and slippage.

As an articulated industrial robot that solves this problem,
The one disclosed in Japanese Patent Application Laid-Open No. 47-7418 was known.

However, in this conventional articulated robot, the hand mechanism (wrist)
It was not possible to drive the posture of the robot, and as an articulated robot, it lacked a degree of freedom, and had the disadvantage of being unable to perform complex assembly and processing operations.

An object of the present invention is to eliminate the drawbacks of the above-mentioned prior art, to gather rotary actuators for driving an articulated robot having at least four degrees of freedom on a support member (shoulder part), to reduce the weight of the arm mechanism, and to reduce the weight of the arm mechanism. The drive mechanism of an articulated robot is designed to easily control the position of the tip of the arm mechanism (the tip of the arm mechanism) and control the hand mechanism in at least two degrees of freedom, making it possible to perform complex assembly and processing operations at high speed. It is on offer.

That is, the present invention provides a support member (shoulder) that supports the arm mechanism on the first axis so that it can be connected to at least two degrees of freedom of the arm mechanism and at least two degrees of freedom of the hand mechanism (wrist) by rotational movement only. The present invention is constructed so that at least four rotational motion outputs can be obtained.

Since a rotary actuator is used as a drive source, the first and second rotary drive shafts are arranged on this first shaft, and the first and second rotary drive shafts are connected to the first and second rotary drive shafts from both sides. The rotary actuators are connected, and first and second rotary members are arranged on the first axis, and third and second rotary members are arranged on a second axis provided on the support member (shoulder) parallel to the first axis. Fourth
a rotary drive shaft, the third and fourth rotary drive shafts are connected to the third and fourth rotary actuators and connected to the first and second rotary members by a connecting member; The first and second rotary actuators and the third and fourth rotary actuators are arranged symmetrically on opposite sides of the shoulder so that at least four rotary motion outputs are obtained on one axis. In addition, the drive mechanism that drives the arm mechanism and the hand mechanism from the drive source can all be configured as rotating pairs.
The present invention is characterized in that the mechanism is simplified, and a drive groove for an articulated robot with excellent durability and high reliability can be obtained.

Hereinafter, the present invention will be specifically explained based on embodiments shown in the drawings.

FIG. 2 is a perspective view of a combination of parts constituting an embodiment of the arm mechanism of an articulated robot according to the present invention, FIG. 3 is an enlarged view of the differential gear mechanism, and FIG. FIG. 3 is an explanatory diagram showing the operating principle of the arm mechanism shown in the figure.

That is, the main body 1 of the articulated robot rotatably supports a shaft 9 fixed to an L fitting 8, and a motor (not shown) for rotating this shaft 9 is mounted.

Reference numeral 10 denotes a support member (hereinafter referred to as a shoulder portion) that supports the arm mechanism, and supports the shaft 11 on the L fitting 8 so as to be rotatable.

This shaft 11 is connected to a motor (not shown) originally mounted on 1 via a ball joint (not shown).

Reference numeral 12 denotes a first rotary drive shaft rotatably supported by the support member 10, which is provided at one end of the first arm member 13, and a first rotary actuator (not shown) which is a motor. ) is connected to the output shaft of the

14 is a second rotary drive shaft rotatably supported by the support member 10 coaxially with the first rotary drive shaft 12, and is provided at one end of the first link member 15, It is connected to the output shaft of a second rotary actuator (not shown), which is a motor.

Note that the connection here includes not only the case of direct connection but also the case of indirect connection via, for example, a reduction gear.

A second link member 17 has the same length as the first arm member 13, and one end thereof is rotatably connected to the swinging end of the first link member 15 by a connecting shaft 16.

Reference numeral 19 denotes a second arm member, which is rotatably connected to the other end of the second link member 17 by a connecting shaft 18, and is further connected to the first arm member.
The arm member 13 is rotatably connected to the swinging end of the arm member 13 by a connecting shaft 20.

The length from the connecting shaft 18 to the connecting shaft 20 is equal to the length of the first link member 15.

Therefore, the first arm member 13, the first link member 15, the second
The link member 17 and the second arm member 19 form a parallelogram link mechanism.

21 is a rond with a hand mechanism such as a chuck for holding an object attached to the tip, and a bevel gear 22 is placed opposite to the rear end.
and 23 are rotatably supported.

A rotating shaft 24 is rotatably supported at the tip of the second arm member 19, and a bevel gear 25 that meshes with the bevel gears 22 and 23 is fixed to one end.

A rotating shaft 26 is rotatably supported at the tip of the second arm member 19, and a bevel gear 27 that meshes with the bevel gears 22 and 23 is fixed to one end.

Therefore, the bevel gears 22, 23, 25, and 27 form a differential gear mechanism 28.

29 is a lever, one end of which is fixed to the rotating shaft 24;
The other end is rotatably coupled to one end of a link member 31 via a pin 30.

A joint plate 32 has a triangular shape and is rotatably supported by the connecting shaft 20. One end is rotatably connected to the other end of the link member 31 by a pin 33, and the other end is connected to the link member 35 by a pin 34. It is rotatably connected to one end of the.

36 is rotatably supported by the first rotary drive shaft 12;
A joint plate having a square shape is formed, and one end is rotatably connected to the other end of the link member via a pin 37,
The other end is rotatably coupled to one end of a link member 39 via a pin 38.

42 is a third rotary drive shaft connected to the output shaft of a third rotary actuator, which is a motor, rotatably supported by the support member 10, and fixed to one end of the crank 41.

The other end of the crank 41 is rotatably coupled to the other end of the link member 39 by a pin 40.

That is, the important point is that the length of the link member 35 is made equal to the distance between the first rotary drive shaft 12 and the connecting shaft 20, and the swing radii of the joint plate 36 and the joint plate 32 are made equal. 35, joint plate 3
2 and 36 to form a parallel linkage.

Similarly, the length of the link member 31 is made equal to the distance between the rotating shaft 24 and the connecting shaft 20, and the swing radius of the joint plate 32 and the lever 29 are made equal, so that the length of the link member 31. The joint plate 32 and the lever 29 form a parallel link mechanism.

43 is a lever, one end of which is fixed to the rotating shaft 26;
The other end is rotatably coupled to one end of a link member 45 via a pin 44.

Reference numeral 46 is a triangular joint plate rotatably supported by the connecting shaft 20, one end of which is rotatably connected to the other end of the link member 45 by a pin 47, and the other end is connected to the link member 49 by a pin 48. It is rotatably connected to one end of the.

Reference numeral 50 is rotatably supported by the second rotary drive shaft 14, is a triangular joint plate, one end is rotatably connected to the other end of the link member 49 via a pin 51, and the other end is is rotatably coupled to one end of a link member 53 via a pin 52.

Reference numeral 56 is a fourth rotary drive shaft connected to the output shaft of a fourth actuator, which is a motor, rotatably supported by the support member 10, and one end of the crank 55 is fixed.

The other end of the crank 55 is rotatably coupled to the other end of the link member 53 by a pin 54.

between the lever 43, the link member 45, the joint plate 46, and the joint plates 46 and 50.
A parallel link mechanism is formed between the link member 49 and the link member 49.

Therefore, the rotation axis 24°26 becomes the base of the hand mechanism, that is, the wrist.
The positional information (X, y) of the point t where is located is given by the following equation (1).

x = 1cosα+mcos(π-β)a=,5. .

cE+msi. (,,,-β))・・・・・・・・・(1
) However, l is the total length of the first arm member 13 as shown in FIG. 4, and m is the length from the connecting shaft 20 to the rotating shaft 24.2 as shown in FIG.
6, α is the length of the first arm member 13 as shown in FIG.
β is the angle between the first link member 15 and the X axis, and β is the angle between the first link member 15 and the X axis, as shown in FIG.

Therefore, when the positional information of a point t (x, y) on the wrist is given, the angles α and β are determined from equation (1), and the first rotary actuator (motor) is adjusted so that the angle α is achieved. The first arm member 13 is rotated by a predetermined angle by rotating the first rotary drive shaft 12, and the angle β
The second rotary actuator (motor) is rotated so that the second rotary drive shaft 14 is rotated so that the first
The link member 15 is rotated by a predetermined angle.

At this time, the third rotary drive shaft 42 and the fourth rotary drive shaft 5
6 is stopped and the joints 36 and 50 are stopped, so the joint plates 32 and 46 are kept parallel to the joint plates 36 and 50, and the levers 29 and 43 are also kept parallel to the joint plates 36 and 50. plate 32
The posture of the rod 21, which is held parallel to the rods 46 and 46 and supports the hand mechanism, is always maintained constant as shown in FIG.

That is, as shown in FIG. 4, for example, even if the first arm member 13 rotates by a predetermined amount, the rod 21 supporting the hand mechanism can always be held in a parallel state, that is, in a fixed direction, and the hand mechanism can be held in a fixed direction. In order to rotate the rod 21 while keeping the supported rod 21 constant, the third rotation drive shaft 42 and the fourth
This can be obtained by rotating the rotary drive shafts 56 of 1 and 2 by the same predetermined amount in opposite directions, and by rotating the bevel gears 25 and 27 of the differential gear mechanism 28 by the same angle in opposite directions.

Furthermore, if it is desired to change only the posture of the rod 21 supporting the hand mechanism without rotating it around the axis, the third rotary drive shaft 42 and the fourth rotary drive shaft 56 can be rotated by the same predetermined amount in the same direction. , bevel gears 25 and 2 of the differential gear mechanism 28
7 by an equal predetermined amount of rotation in the same direction relative to each other.

The rod 21 supporting the hand mechanism can move freely within the same plane as described above, but horizontal movement can be achieved by rotating the vertical shaft 9 with a motor, Rotation about the support member 10 can be achieved by means of a motor on the shaft 11 to which the support member 10 is fixed.

As explained above, according to the present invention, the drive source is concentrated on the support member (shoulder) closest to the main body of the industrial robot,
In a drive mechanism for driving an articulated robot designed to reduce weight and simplify the mechanism, a first rotary drive shaft is connected to a 10-turn rotary actuator, and a second rotary drive shaft is connected to a second rotary actuator. A third rotary drive shaft is rotatably supported on a support member so that the axis of the rotary drive shaft is aligned with the first axis, and a third rotary drive shaft is connected to a third rotary actuator, and a fourth rotary drive shaft is connected to a third rotary actuator. A fourth rotary drive shaft connected to the shaped actuator is rotatably supported on a support member on a second shaft whose axis center is parallel to the first shaft, and each output of the third and fourth rotary drive shafts is is connected to the first and second rotating members provided on the first shaft by a connecting member, and the first and second rotary drive shafts and the first and second rotating members are connected to each other on the first shaft. Since the configuration is configured to obtain at least four rotational movements, it is possible to connect the drive source to the arm mechanism and hand mechanism by rotational movement, and to achieve high-speed and smooth operation.
Moreover, the posture of the hand mechanism can be controlled with two degrees of freedom independently of the arm mechanism, making it possible to perform complex assembly and processing operations with a wide range of movement. It has the advantage of being able to be placed in an articulated robot with good weight balance and high-speed operation, and the drive mechanism can be configured as a rotating pair, which simplifies the mechanism and makes it possible to obtain an articulated robot with excellent durability and high reliability. play.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing the arm mechanism of a conventional articulated robot, FIG. FIG. 4 is an enlarged view of the differential gear mechanism, and is a diagram showing the operating principle of an embodiment of the arm mechanism of the articulated robot shown in FIG. 2. 1... Main body of articulated robot, 10...
・Support member (shoulder part), 12...First rotational drive shaft, 13...First arm member, 15...
First link member, 17... Second link member, 19... Second arm member, 14... Second rotational drive shaft, 21... ...Rod, 24°26
...Rotary axis, 29,43...Lever,
31° 35.39, 45, 49.53... Link member, 32.36, 46.50... Joint plate, 41.55... Crank, 42.
...Third rotary drive shaft, 56...Fourth rotary drive shaft.

Claims (1)

[Claims] 1. In a drive mechanism for driving an articulated robot having at least four degrees of freedom, the arm mechanism of the articulated robot is rotatably supported on a first axis provided on a support member;
a first rotary drive shaft connected to the first rotary actuator; and a second rotary drive shaft connected to the second rotary actuator.
A rotary drive shaft, a first rotary member, and a second rotary member are each supported on the first shaft so as to be rotatable independently, and are connected to a third rotary actuator; 3
A third rotary drive shaft to which a rotating member is fixed, and a fourth rotary drive shaft connected to a fourth rotary actuator and to which a fourth rotary member is fixed are connected in parallel to the first axis. The first rotating member is supported on a second shaft provided on a support member so as to be able to rotate independently, and the second rotating member is supported on a second axis that is rotatable independently of the third rotating member. A drive mechanism for an articulated robot, characterized in that the drive mechanism is connected to each member via a connecting member so that four rotational movements can be obtained in the first axis.