KR20120022318A - Multiaxial joint robot for vertical polyarticular - Google Patents

Abstract

PURPOSE: A multi-axis vertical articulated robot is provided to control a tensile force of tensile force generating units because a force for pulling an upper arm of a robot is optimally controlled by a separate clamping device. CONSTITUTION: A multi-axis vertical articulated robot comprises a two-axis unit(30), a three-axis unit(40), and a pair of tensile force generating units. A vertical three-axis rod(41) is installed in the two-axis unit to be rotated. A three-axis body(42) is installed in the upper part of the vertical three-axis rod. The pair of the tensile generating units are installed between a two-axis body(31) of the two-axis unit and the three-axis body of the vertical three-axis rod.

Description

Multiaxial joint Robot for vertical polyarticular}

The present invention relates to a multi-axis vertical articulated robot, and more particularly, a tension force generating means is installed between two and three axes to minimize the influence of gravity on the two axes of rotation to apply a small motor to the robot axis of rotation. The present invention relates to a multi-axis vertical articulated robot that can contribute to minimizing the space of the robot mechanism and reducing the weight of the robot.

In the case of a welding device or a robotic system that is portable while working in an industrial workplace, interest in the weight of the device or system is continuously increasing because the convenience and safety of the operator is the most important.

In the welding field, a robotic device having 1 to 3 axes is used for a simple welding operation. However, in case of basic U-Cell in ship block, multi-joint robot with 6 axes of about 3kg payload is needed to realize various welding motions.

The small 6-axis vertical articulated robot on the market as an industrial robot has a robot body weight of about 25 to 60 kg. Since the robot weight specification is difficult to meet the needs of the field customers, the necessity of developing the robot weight is raised.

In the case of industrial 6-axis vertical articulated robot, when 2 and 3 axes rotate, the 2 and 3 axes are most affected by gravity. Therefore, the motor capacity required for two and three axes is often the largest. In the case of a large-sized 6-axis vertical articulated robot with a payload of 10kg or more, the influence of gravity is minimized by using weight balance or hydraulic balance. The situation is raising. These balances are known to have a gravity damping effect of about 80%.

The series 6-axis vertical articulated robot is a structure that can be easily exposed to the effects of gravity in kinematic or dynamical in link-to-link connection. In addition, the 5-bar linkage type 6-axis vertical articulated robot that makes the connection between the robot links in parallel is difficult to avoid the effects of gravity in the case of 2 and 3 axes.

To overcome this problem, robot developers are installing hydraulic balance on two axes of the robot and weight balance on the three axes of the robot to counteract the effects of gravity and improve motor control.

However, in the case of a small 6-axis vertical articulated robot, the weight or the hydraulic balance itself can add weight, and since it is difficult to install mechanically, the robot employing such a balance is difficult to find in the market.

In many applications where the robot weight specification is not important, there is no problem when a general small 6-axis vertical articulated robot is easily purchased and used. However, in the case of welding robots requiring work movement, the research on miniaturization and lightening of robots is constantly being attempted.

In the present invention, in a small 6-axis vertical articulated robot, a tension force generating means is installed between two axes and three axes at an appropriate position according to the robot rotation radius to minimize the influence of gravity.

In addition, by placing a separate clamping device for optimally adjusting the force to pull the robot upper arm to adjust the tension of the tension generating means.

In order to weld a U-Cell with a horizontal length of 850mm and a vertical height of 350mm with a 6-axis vertical articulated robot, about 3kg of payload and about 300mm + 315mm (Lower Arm + Upper Arm) of the robot are required. In the case of a general industrial robot with this specification, each axis uses a servo motor in the range of about 50 to 200W.

The present invention provides a multi-axis vertical articulated robot that reduces the kinematic size and weight of a robot by using a 30W class servo motor by minimizing the influence of gravity by applying a tensile force generating means to two axes having the greatest influence of gravity.

In the present invention, a tension spring or a hydraulic return device, which is generally easily obtained between two and three axes, is installed at an appropriate position according to the rotation radius of the robot as a tension generating means, thereby minimizing the influence of gravity, and It is configured to adjust the value of the tensile force constant by having a separate clamping device for optimally adjusting the pulling force.

The present invention can be applied to a rotation axis having the greatest gravity effect of the robot by applying a tension spring that is commonly available around us, so that this small, lightweight, articulated robot specification is applied as one solution. It can satisfy the precision and controllability of the desired robot.

1 is an external configuration diagram of a six-axis small vertical articulated robot using a tension spring balance according to the present invention.
Figure 2 is a side configuration diagram of a six-axis small vertical articulated robot using a tension spring balance according to the present invention.
Figure 3 is a side configuration diagram of a six-axis small vertical articulated robot having a hydraulic return device as a tensile force generating means according to the present invention.
Figure 4 is an explanatory view showing the change in length of the tension spring according to the robot two-axis rotation according to the present invention.
Figure 5 (a) and (b) is a diagram illustrating the kinematic rotational motion according to the rotation of the two axes of the robot for explaining the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an external configuration diagram of a six-axis miniature vertical articulated robot using a tension spring balance according to the present invention, and FIG. 2 is a side configuration diagram of a six-axis miniature vertical articulated robot using a tension spring balance according to the present invention.

As shown therein,

A one-axis motor unit 20 having a built-in one-axis motor installed on one side of the robot body 10,

The two-axis unit 30 is horizontally rotated by the one-axis motor and the two-axis motor 30 is installed inside the two-axis body 31, and the three-axis rod 41 in the vertical direction is vertically driven by the two-axis motor. A three-axis portion 40 in which a three-axis motor is installed in the three-axis body 42 installed at an upper end of the three-axis rod 41 and rotated in a vertical direction by the three-axis motor and a four-axis motor therein. Is installed to enable horizontal rotation by a 5-axis unit 50 having a built-in 4-axis unit 50 and a 5-axis unit 60 and a 5-axis unit 60 rotated in a horizontal direction by a 4-axis motor and installed inside the 5-axis motor. It consists of a torch part 70.

In the six-axis small welding robot configured as described above, the three-axis portion 40 rotated by the two-axis portion 30 is a three-axis arm is installed in the vertical direction, the upper arm is installed on the upper portion of the three-axis portion 40 The upper arm is composed of a 4-axis portion 50, a 5-axis portion 60, and a torch portion 70 to receive the greatest force.

Therefore, in the present invention, the tension spring 100 is installed between the outer surface of the two shaft body 31 of the two shaft portion 30 and the outer surface of the three shaft body 42 of the three shaft portion 40 to pull the upper arm. It is designed to minimize the influence of gravity by force. The tension springs 100 are respectively installed on both sides and installed to form a pair.

3 is a side configuration diagram of a six-axis small vertical articulated robot having a hydraulic return device as a tensile force generating means according to the present invention. As shown in FIG. 1, instead of the tension spring 100 of FIGS. 1 and 2, the hydraulic return device 100 ′ may be installed as a tensile force generating means. The hydraulic return device 100 ′ exhibits a tension force when the fluid filled in the cylinder is pulled out of the piston to function as a tension spring. That is, in the present invention, the tension spring generating means 100 may be used or the hydraulic return device 100 'may be used.

On the other hand, the clamp 200 is formed on the outer surface of the biaxial body 31 is formed with a multi-stage coupling portion 201 for adjusting the fixing position of the tension spring 100 differently.

According to the present invention, when the three-axis rod 41 of the three-axis portion 40 is rotated in the vertical direction by a two-axis motor installed in the two-axis portion 30 of the robot, the tension spring 100 is the upper arm ( Gravity is compensated by pulling in the normal direction of the rotation radius with respect to the 4-axis part, the 5-axis part, and the torch part. Therefore, this compensated force requires less torque as compensating gravity from the standpoint of the servomotor, a two-axis motor.

Figure 4 is an explanatory view showing the change in length of the tension spring according to the robot two-axis rotation according to the present invention.

The initial length of the tension spring 100 was 192.5mm, but when the two shafts rotate 45 degrees 236.5mm, when rotated 90 degrees 318.7mm will be increased 44mm, 126.2mm compared to the initial length, respectively.

When the tension spring constant is defined as k, the pulling force F = k × elongated length (x) is defined as the normal force of the rotation radius by the F force to compensate for gravity. Therefore, this compensated force takes less torque as compensating gravity from the standpoint of the servomotor, and in this way it is possible to rotate large loads even with a small motor.

Equation (1) below developed the equation according to the rotational motion of the robot two axes. Therefore, applying the formula below, we can see how much the tension spring rotates according to the robot's rotation and how much pulling force is generated to compensate for gravity.

5 (a) and 5 (b) are explanatory diagrams of kinematic rotational motion according to rotation of two robot axes for explaining the present invention.

When the two shafts are rotated in the same state as in FIG. 5 (b) in the state as shown in FIG. 5 (a), it can be seen whether torque applied to the tension spring is applied. In other words, the torque applied to the tension spring can compensate for the torque against gravity applied to the upper arm.

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Equation (1)

는 상부암에 작용되는 토크,

는 인장 스프링에 작용되는 토크

Is the torque acting on the upper arm,

Is the torque acting on the tension spring

On the other hand, the two axes of the robot is installed a separate clamp 200 that can adjust the pulling force to the tension spring (100).

The clamp 200 has a coupling part 201 formed in multiple stages for fixing and fixing one end of the tension spring 100. That is, several holes are drilled to change the mounting position of the tension spring 100.

The method for adjusting the pulling force of the tension spring 100 includes a method of adjusting the pulling force by adjusting the k value by changing the material property of the material of the tension spring 100 or the size of the spring diameter, and FIG. 3. By changing the initial position of the tension spring 100, such as the clamp 200, the pulling force can be adjusted by adjusting the elongated length.

Through proper use of the tension spring 100 through the present invention, the servomotor used for two-axis rotation is reduced by one or two steps than the existing industrial robot. (In the case of the existing industrial robot, the 100W class servo motor is used. By using the invention, it is possible to reduce the mechanical size by using a 30W class servo motor), and accordingly the weight of the robot body can be reduced by the reduced size.

10: robot body 20: 1-axis motor unit
30: 2-axis part 31: 2-axis body
40: 3-axis part 41: 3-axis rod
42: 3-axis body 50: 4-axis
60: 5-axis portion 60: torch portion
100: tension spring 100 ': hydraulic return device
200: clamp 201: coupling portion

Claims (4)

In a multi-axis vertical articulated robot,
Between the two-axis body 31 of the two-axis portion 30, the three-axis rod 41 in the vertical direction is rotatably installed, and the three-axis body 42 installed on the upper end of the three-axis rod 41 in the vertical direction. Multi-axis vertical articulated robot, characterized in that installed by installing a pair of tension generating means.
According to claim 1, wherein the clamp 200 is formed on the outer surface of the biaxial body 31 is formed with a multi-stage coupling portion 201 for differently adjusting the one side end fixing position of the tension generating means Multi-axis vertical articulated robot, characterized by.
The method of claim 1 or 2, wherein the tension generating means,
A multi-axis vertical articulated robot, characterized in that it is a tension spring.
The method of claim 1 or 2, wherein the tension generating means,
Multi-axis vertical articulated robot, characterized in that the hydraulic return device.

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