JPH0160396B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a robot having a five-bar link structure.

Conventionally, arm-type link robots as shown in Figure 1 have been used. In this arm-type robot, the first arm 31 is directly driven by a first drive section 33 installed on the second arm 32 in order to improve positioning accuracy. For this reason,
When the second arm 32 is driven by the second drive unit 34, the inertia of the first drive unit 33 is added, and the inertia applied to the rotation axis of the second drive unit 34 becomes large. The section 34 has the drawback of requiring a large output. Furthermore, since the arm type is basically an open-loop structure, it has the unavoidable drawback of low rigidity of the arm portion. Further, a parallel link type as shown in FIG. 2 has also been used in the past. This parallel link type robot has 2
Since the two drive sections 41 are installed on the same axis, the posture of the apparatus becomes high, and the required outputs of the two drive sections 41 are different due to the structure, making it easy to lose balance.

Therefore, the present inventors have long proposed the application of a five-bar linkage mechanism to robots, and have conducted various theoretical and experimental studies. Its basic features can be summarized in the following three points.

(1) Closed-loop structure allows for dramatically higher rigidity and weight reduction.

(2) High machining accuracy is required only for the distance between the axes, and parts are generally easy to process and assemble. Therefore, it can be done at low cost.

(3) High operational reliability and high-speed operation.

The schematic diagram shown in FIG. 3 was proposed by the present inventors prior to the present invention. However, as a result of repeated studies under the conditions that industrial robots actually encounter, this conventional configuration was
Although I was able to confirm the basic advantages of the above three points, and my confidence increased, there were still some drawbacks. That is, in the case of the configuration shown in FIG. 3, the rotary brake 51 is installed only at two locations: the connection point between the first link 52 and the second link 53, and the connection point between the first link 52 and the third link 54. Therefore, in order to firmly maintain the position of the attachment point 55 of the working mechanism even if some external force is applied to the link, it becomes necessary to use a rotary brake 51 with a large output.
And even after doing this, joints 56, 57, 58
Even if the error becomes slightly larger, the positional accuracy of the working mechanism attachment point 55 will deteriorate significantly. Furthermore, it has also been found that it is difficult to dampen residual vibrations of the link that occur during positioning of the working mechanism attachment point 55 in a short period of time.

The purpose of the present invention is to eliminate the newly discovered drawbacks mentioned above, to provide a new five-bar link that has the inherent high rigidity of a five-bar link robot, and that can perform high-accuracy positioning at high speed with a low-output rotation mechanism. Our goal is to provide robots.

According to the present invention configured as claimed, the working mechanism is rotated by rotating the second link and the third link with the same output and with the low output first rotation mechanism and second rotation mechanism. A novel five-bar link robot is obtained in which the attachment point can be moved to any position on a plane and the rigidity of the links is increased by rotary brakes provided at the connection points of each link.

Hereinafter, as an example of a typical implementation of the present invention, a general-purpose working mechanism equipped with a hand attachment part that freely rotates in a uniaxial direction will be described.
This will be explained more specifically. The key points of the efforts made to install such a hand attachment part are as follows. First, a first link fixed on one plane,
a second link whose one end is rotatably connected to one end of the first link and rotates around the connection point;
One end is rotatably connected to the other end of the first link, and a third link rotates in the same manner as the second link; one end is rotatably connected to the other end of the second link, and the connecting point is a fourth link that rotates on the plane at the center; one end is rotatably connected to the other end of the third link, rotates in the same manner as the fourth link, and the other end is connected to the other end of the fourth link; a fifth link that is rotatably connected to the first link; and a first rotation mechanism that is installed at a connection point between the first link and the second link and rotates the second link at a predetermined angle with respect to the first link. and a second rotation mechanism that is installed at a connection point between the first link and the third link and rotates the third link at a predetermined angle with respect to the first link, forming a five-bar link. , a connection point between the first link and the second link, a connection point between the first link and the second link, and a connection point between the first link and the second link.
A connection point between a link and the third link, a connection point between the second link and the fourth link, a connection point between the third link and the fifth link, and a connection point between the third link and the fourth link.
first, second, third, and third links that brake the rotational motion of the link and the fifth link, respectively;
fourth and fifth rotary brakes, and further includes a freely rotatable hand attachment part at a connection point between the fourth link and the fifth link, and a fixed position on the first link; Freely rotatable first, second, and A third transmission wheel and a fourth transmission wheel are provided, the first transmission wheel and the second transmission wheel, the second transmission wheel and the third transmission wheel, and the third transmission wheel and the fourth transmission wheel. and a third rotation mechanism for rotating the first transmission wheel at a predetermined angle, each of which is provided with a first, second, and third conduction band, the first rotation mechanism and the second transmission wheel. A control unit that controls the movement of each of the rotation mechanism, the first rotation brake, the second rotation brake, the third rotation brake, the fourth rotation brake, the fifth rotation brake, and the third rotation mechanism. A five-section link robot was constructed.

FIG. 4 is a perspective view schematically showing a more specific example of the above embodiment, and FIG. 5 is a schematic diagram showing the structure of the link in FIG. 4.

1 is a first link fixed on a plane. 2
has one end rotatably connected to one end of the first link,
This is a second link that rotates on a plane using the first joint 3 as a fulcrum. Reference numeral 4 designates a third link whose one end is rotatably connected to the other end of the first link 1, and which rotates on a plane using the 21st joint 5 as a fulcrum. 6 connects one end to the other end of the second link 2 in a freely rotatable manner;
This is the fourth link that rotates around the third joint 7 as a fulcrum. 8 has one end rotatably connected to the other end of the third link 4, rotates on a plane using the fourth joint 9 as a fulcrum, and has the other end rotatably connected to the other end of the fourth link 6. This is the fifth link. 1
0 is the connection point between the fourth link 6 and the fifth link 8, which is the fifth joint. 11 is a hand attachment part;
In this embodiment, it is installed at the center of the fifth joint 10,
It is configured to rotate around its center. 1
2 is an example of the first rotation mechanism, and the first joint 3
This is a first servo motor that is installed above and rotates the second link 2 to set the connection angle θ ₁ between the first link 1 and the second link 2 to a predetermined value. 13 is an example of a second rotation mechanism, which is installed on the second joint 5 and rotates the third link 4 to set the connection angle θ ₂ between the first link 1 and the third link 4 to a predetermined value. This is the second servo motor to be set. 14 is an example of a first rotary brake, which is installed on the first joint 3 to brake the rotation of the second link 2 and finally adjust the connection angle θ ₁ between the first link 1 and the second link 2. This is a first electromagnetic brake that fixes the brake. 15 is an example of a second rotary brake, which is installed on the second joint 5 to brake the rotation of the third link 4 and finally adjust the connection angle θ ₂ between the first link 1 and the third link 4. This is a second electromagnetic brake that fixes the position. 16 is an example of a third rotary brake, in which a third electromagnetic brake is installed on the third joint 7 and brakes the change in the connection angle θ ₃ between the second link 2 and the fourth link 6 and finally fixes it. It's the brakes. Reference numeral 17 is an example of a fourth rotary brake, in which a fourth electromagnetic brake is installed on the fourth joint 9 and brakes changes in the connection angle θ ₄ between the third link 4 and the fifth link 8 to finally fix it. It's the brakes. 18 is an example of a fifth rotary brake, which is installed on the fifth joint 10 and brakes the change in the connection angle θ ₅ between the fourth link 6 and the fifth link 8 and finally fixes it. It is an electromagnetic brake.
Reference numeral 19 denotes a first pulley as an example of a first transmission wheel which is fixed to a fixed position on the first link 1 so as to be freely rotatable, and 20 is a first pulley which is rotatably installed on the first joint 3. It is a second pulley as an example. 21 is a third pulley as an example of a third transmission wheel installed freely on the third joint 7;
Reference numeral 22 denotes a fourth pulley as an example of the fourth transmission wheel fixed to the hand attachment portion 11. 23 is a first belt as an example of a first transmission band in which the first pulley 19 and the second pulley 20 are interlocked;
4 is a second belt as an example of a second transmission band in which the second pulley 20 and the third pulley 21 are interlocked, and 25 is a third transmission belt in which the third pulley 21 and the fourth pulley 22 are interlocked. This is a third belt as an example of the belt. 26 is a third servo motor constituting a third rotation mechanism that rotates the first pulley 19 at a predetermined angle. 27, the first servo motor 12, the second servo motor 13, and the third servo motor 12;
Servo motor 26, the first electromagnetic brake 1
4. A control unit that controls the movements of the second electromagnetic brake 15, the third electromagnetic brake 16, the fourth electromagnetic brake 17, and the fifth electromagnetic brake 18.

Next, the operation of the above embodiment will be specifically explained.

The first servo motor 1 is controlled by the control unit 27.
2, the second link 2 is rotated, the connection angle θ ₁ between the first link 1 and the second link 2 is set to a predetermined value, and at the same time, the second link 4 is rotated by the second servo motor 13, and the first Connection angle between link 1 and third link 4 θ ₂
Set to a predetermined value. With this, the connection angles θ ₃ , θ ₄ , and θ ₅ of the other links are determined based on the structure of this link, and the hand attachment portion 11 is moved to a predetermined position.

In addition, the first electromagnetic brake 1 installed on each joint
4, second electromagnetic brake 15, third electromagnetic brake 1
6, 4th electromagnetic brake 17, 5th electromagnetic brake 1
8 and 8 are respectively controlled by the control unit 27, and are gradually activated immediately before the coupling angles θ ₁ and θ ₂ are set to predetermined values. By operating in this manner, each electromagnetic brake plays the role of a damper, producing the effect of suppressing vibrations that occur when the link is stopped, so that the hand attachment portion 11 can be positioned quickly. Furthermore, when each electromagnetic brake is fully activated after the positioning of the hand attachment part 11 is completed, the connection angle θ ₁ of the link,
θ ₂ , θ ₃ , θ ₄ , and θ ₅ are fixed, and the position of the hand attachment portion 11 can be firmly held without changing even if some force is applied to the link. Then, when the third servo motor 26 rotates the first pulley 19 by a predetermined angle, the first belt 2
3 to the second pulley 20, from the second pulley 20 to the third pulley 21 via the second belt 24, and from the third pulley 21 to the fourth pulley 22 via the third belt 25. Transmits 19 movements,
The hand attachment portion 11 fixed to the fourth pulley 22 is set in a predetermined posture. Therefore, a chuck or the like (not shown) installed in the hand attachment section 11 performs the work. Note that if the distance between each pulley is constant, the relationship between the pulley and the belt is kept constant, so the third
The power of the servo motor 26 is transmitted, and the posture of the hand attachment section 11 can be set. here,
Considering the magnitude of the contribution to the holding force of the link when the output torque of each electromagnetic brake is the same, due to the structure of the link, the third electromagnetic brake 16 and the fourth electromagnetic brake are stronger than the first electromagnetic brake 14 and the second electromagnetic brake 15. 17 is larger, and the fifth electromagnetic brake is larger than the third electromagnetic brake 15 and the fourth electromagnetic brake 16.
The electromagnetic brake 17 is larger. This means that the present invention newly provides the third electromagnetic brake 15 and the fourth brake.
It is shown that by installing the electromagnetic brake 16 and the fifth electromagnetic brake 17, the posture holding force of the entire link is significantly increased. Now,
In this embodiment, servo motors 12 and 1 are used as rotational drive sources constituting the first, second, and third rotation mechanisms.
3 and 26 are used, but this is not limited to a servo motor; for example, a pulse motor or the like may of course be used. Furthermore, in the above embodiment, the transmission band and the transmission wheel are explained as using a belt and a pulley, respectively, but the invention is not limited to this, and it is of course possible to use a timing belt and a timing pulley, a chain and a sprocket, etc. It is. Note that when performing highly accurate positioning, it is desirable to use a timing belt and a timing pulley.

By the way, although the first and second rotation mechanisms are directly connected to the rotation centers of the respective links in this embodiment, they may be installed outside to drive the links indirectly. Furthermore, although we have explained that the first, second, third, fourth, and fifth rotary brakes use electromagnetic brakes that are directly connected to the rotating shaft of each link, mechanical brakes may also be used. , muscle-like mechanisms that externally fixate each joint can also be used.

Further, although an example has been shown in which the rotational positioning of the hand mounting portion is performed indirectly using a transmission band and a transmission wheel, this is not limited to this either. It is also possible to directly connect the third rotation mechanism to the rotation shaft of the hand attachment part. If the third rotation mechanism is directly connected to the rotating shaft of the hand attachment part, the entire configuration can be simplified and the positioning accuracy can be improved. However, when the link is driven, the inertia of the third rotation mechanism is added, and the
Since the inertial force applied to the rotation shaft of the second rotation mechanism increases, it becomes necessary to increase the outputs of the first and second rotation mechanisms in order to obtain the same drive speed. If the output is left unchanged, the drive speed will decrease. In the case of the configuration in which power is transmitted using the transmission wheel and transmission band described in the above embodiment, the hand attachment portion can be made lightweight, so there is an advantage that the driving speed can be increased while maintaining a small output. Therefore, the selection will depend on the purpose.

Furthermore, although an example has been described in which a shaft-directly connected motor is used as the rotation mechanism, there is no need to limit this mechanism to this type of mechanism either. For example, as shown in FIG. 6, the rack 61, pinion 62, cylinder 6
It is also possible to use the mechanism configured in point 3.

As explained above, according to the present invention, an inexpensive robot can be obtained because the closed loop structure is adopted and the structure is simple. Moreover, since it is possible to use a low-output drive motor and at the same time has high rigidity, highly accurate positioning can be performed at high speed. Furthermore, by using parts with corrosion resistance in mind, a brake is installed on each joint to increase the holding power of the link, so even when working under external forces such as on the seabed with tidal currents, the working mechanism remains stable. The effect is remarkable because the position does not change.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the basic configuration of a conventional arm type robot, and FIG. 2 is a schematic diagram showing the basic configuration of a conventional parallel link type robot. FIG. 3 is a schematic diagram illustrating the conventional configuration of a five-bar link type robot previously proposed by the present inventors in order to eliminate these conventional drawbacks. FIG. 4 is a schematic diagram showing the configuration of an embodiment of the present invention, which is an improvement over the conventional configuration shown in FIG. 3, and FIG. 5 is a schematic diagram for explaining the configuration of the link in FIG. It is a diagram. FIG. 6 is a schematic diagram showing another example of the configuration of the rotational drive mechanism of the present invention. In the figure, 1 is the first link, 2 is the second link, 3 is the first joint, 4 is the third link, 5 is the second joint, 6 is the fourth link, and 7 is the third link.
Joints, 8 is the fifth link, 9 is the fourth joint, 10 is the fifth joint, 11 is the hand attachment part, 12 is the first servo motor, 13 is the second servo motor, 14
is the first electromagnetic brake, 15 is the second electromagnetic brake,
16 is a third electromagnetic brake, 17 is a fourth electromagnetic brake, 18 is a fifth electromagnetic brake, 19 is a first pulley, 20 is a second pulley, 21 is a third pulley, 22
indicates the fourth pulley, 23 the first belt, 24 the second belt, 25 the third belt, 26 the third servo motor, 27 the control section, 61 the rack, 62 the pinion, and 63 the cylinder, respectively. ing.

Claims (1)

[Claims] 1 A first link fixed on one plane, a second link having one end rotatably connected to one end of the first link and rotating around the connection point, and one end connected to the other end of the first link. The second
a third link that rotates in the same way as the link; a fourth link that has one end rotatably connected to the other end of the second link and rotates on the plane about the connection point; and one end that rotates on the plane a fifth link which is rotatably connected to the other end and rotates in the same manner as the fourth link, and whose other end is rotatably connected to the other end of the fourth link; and the first link and the second link.
a first rotation mechanism installed at a connection point with a link and rotating the second link at a predetermined angle with respect to the first link; installed at a connection point between the first link and the third link; a second rotation mechanism that rotates the third link at a predetermined angle with respect to the first link, forming a five-bar link; a connection point between the first link and the second link; and the third link, a connection point between the second link and the fourth link, a connection point between the third link and the fifth link, and a connection point between the fourth link and the fifth link. The connection point is provided with first, second, third, fourth, and fifth rotary brakes for braking the rotational motion, respectively, and the connection point between the fourth link and the fifth link is connected to the working mechanism. Five-bar link robot used as an attachment point.