JP2003513813A - Oriented robot arm assembly - Google Patents

Abstract

(57) Abstract: A robot arm assembly and a method for moving a workpiece while maintaining a fixed orientation. A robot arm assembly (10) and method for moving a workpiece (12) while maintaining a fixed orientation rotatably supports a first pulley (20) at a first end (16). A first link (14). A second pulley (22) is located at the second end (18) of the first link (14). The coupling (24) prevents relative rotation between the first pulley (20) and the second pulley (22). The first and second pulleys (20), (22) have different radii, whereby the rotation ratio is determined. A release tool (26) for releasably gripping the workpiece (12) is fixed to the first pulley (20). The second link (28) is supported at a first end (30) of the support and is rotatably supported at the second end (34) by the first link 14. The coupling (24) of the pulleys (20), (22) is such that when the second link (28) rotates with respect to the support and the first link (14) rotates with respect to the second link (28), Limit rotation of tool (26) and workpiece (12) with respect to reference plane A. Rotating the first link (14) with respect to the second link (28) is the role of the robot motion software program for moving the workpiece (12).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a robot arm assembly utilized to transfer a work piece.

[0002]

[Prior art]

A workpiece transfer mechanism is used to move the workpiece between work terminals. One example of how the workpiece transfer mechanism is utilized is in a panel press line for automobiles. In an automobile panel press line, panels are moved through a line of a press machine and sequentially pressed to form a desired panel shape. For economic reasons, minimizing cycle time is very important.

In the conventional method, the panel is removed from the first press machine in a straight path, once removed from the first press machine, 18 before being placed on the second press machine.
It is necessary to rotate it by 0 degrees. This entire pathway is inefficient. This inefficiency increases when moving large and heavy panels. Optimal cycle times are achieved if the panel is a straight path that is not rotated. The rotation of the workpiece places a significant inertial load on the transfer mechanism, necessitating a large and costly structure.

US Pat. No. 3,010,587 to Hollinger discloses a workpiece transfer mechanism adapted to move a workpiece in a linear path between press machines. The workpiece transfer mechanism of Hollinger's 3,010,587 patent comprises a stationary sprocket wheel that is adjustably fixed to the upper surface of a support plate. A shaft from the power drive extends vertically above the sprocket wheel.

A main radial arm is fixed on the shaft. The second vertical shaft
It is rotatably mounted on the second end of the main radial arm. A rotating sprocket wheel is fixed to the lower end of the second vertical shaft. The rotating sprocket wheel is connected to the stationary sprocket wheel by a chain. The first end of the auxiliary radial arm is secured to the rotating sprocket wheel. Gripping means for releasably gripping the workpiece is arranged at the second end of the auxiliary radial arm.

Linear movement of the workpiece is accomplished by a primary radial arm and an auxiliary radial arm having an equivalent effective length, and a radial ratio between the stationary sprocket wheel and the rotating sprocket wheel of 1 to 2. Achieved by keeping at 2.
In operation, the power drive means rotates the main radial arm in a counterclockwise direction, and since the stationary sprocket wheel and the rotary sprocket wheel are connected, the auxiliary radial arm rotates clockwise.

The Hollinger transfer mechanism moves the workpiece in a straight path, but rotates the workpiece 180 degrees with respect to the support. The rotation of the work piece or panel creates a significant inertial load, which limits the size of the work piece that can be transferred in a given structure. In addition, the rotation of the part prevents the optimum cycle time from being achieved. In addition, the Hollinger transfer mechanism is not programmable to accommodate pitch or height variations between press machines, or has a slight longitudinal direction to assist with work piece or panel release as is possible with the use of robots. Or it cannot meet the frequent need to add lateral movement.

[0008]

SUMMARY OF THE INVENTION AND ADVANTAGES

The present invention relates to a robot arm assembly utilized to move a workpiece between work terminals while maintaining the orientation of the workpiece with respect to a reference plane. The robot arm assembly includes a first link having first and second ends, a tool attached to the first end of the first link, and a first end rotatably attached to the support. A second link having a second end rotatably attached to the first link is provided. The robot arm assembly has a second link that rotates with respect to the support,
And is characterized by a coupling between the second link and the tool that limits rotation of the tool with respect to the reference plane when the first link rotates with respect to the second link.

The present invention provides for rotating the second link about the support, rotating the first link with respect to the second link, and a predetermined rotation ratio of the second link to the first link. A method of moving a workpiece, including rotating the tool with respect to a first link. Furthermore, the steps of rotating the second link around the support, rotating the first link with respect to the second link, and adjusting the rotation angle of the work piece are performed by a robot operating software program that moves the work piece. Achieved as part.

The robot arm assembly does not require the workpiece to be rotated 180 degrees and maintains the orientation of the workpiece during transfer between work terminals. Optimal cycle times can be achieved by maintaining the orientation of this workpiece. In addition, maintaining the orientation of the workpiece minimizes the inertial loads on the robot arm assembly caused by rotation of the workpiece.

Other advantages of the invention will be readily apparent as they will be better understood when considered in conjunction with the accompanying drawings in view of the following detailed description.

[0012]

Detailed Description of the Preferred Embodiments

Referring now to the drawings, like numerals indicate like or corresponding parts throughout the several views. A robot arm assembly 10 that moves a workpiece 12 while maintaining a constant orientation of the workpiece 12 is shown in FIG. The robot arm assembly 10 comprises a first link 14 having a first end 16 and a second end 18. A tool 26 is rotatably attached to the first end 16 of the first link 14. A coupling 24 is provided to limit rotation of the tool 26 with respect to the reference plane A. The coupling 24 includes a first pulley 20 rotatably supported at a first end 16 of the first link 14 and a second pulley 20 disposed at a second end 18 of the first link 14. The pulley 22 is provided. Pulley 20 and tool 26
Are fixedly connected.

The robot arm assembly 10 controls to drive the links 28, 14 of the robot arm assembly 10 in accordance with a robot operation software program that can obtain a required operation of the robot arm assembly 10 and an operation of the tool 26. Controlled by the system.

The pulleys 20, 22 shown in FIG. 1 have grooved peripheral edges (not numbered).
Is disk-shaped with a peripheral portion having and is connected by a belt 24 provided around the pulleys 20, 22 and arranged in a grooved peripheral edge. It will be appreciated that the combination of pulleys 20 and 22 and belt is but one of many possible connections. Examples of other configurations may include sprocket and chain configurations, lever configurations, or gear systems. Still other coupling means known in the art may be used in place of the preferred forms of pulleys 20,22 and belt 24.

The robot arm assembly 10 is provided with a second link 28 having a first end 30 attached to a support 32 and a second end 34 rotatably connected to the first link 14, and It is characterized by a coupling 24 that limits rotation of the tool 26 with respect to the reference plane A when the second link 28 rotates with respect to the support 32 and the first link 14 rotates with respect to the second link 28. The second link 28 shown in FIG. 1 comprises two links mounted at the central pivot axis. The central pivot axis provides an overall distance between the first and second ends of the second link 28,
It can be changed during movement of the workpiece 12. FIG. 3 illustrates how this configuration allows the robot arm assembly 10 to extend into a restricted area while maintaining the orientation of the workpiece 12 substantially unchanged with respect to the reference plane A.

Referring now to FIG. 2, the first and second pulleys 20, 22 have different radii so as to form a certain rotation ratio. The second pulley 22 in the first embodiment
The ratio of the radius of the first pulley 20 to the radius of is 1 to 2. It will be appreciated that the ratio of the radius of the first pulley 20 to the radius of the second pulley 22 will vary with the application and can therefore be adjusted to accommodate multiple configurations of the robot arm assembly 10. Referring now to FIG. 4, the radius ratio between the pulleys can be determined using the equation below.

Δθ3 = Δθ2 (1- (R1 / R3)) + (Δθ1) Equation 1 Here, Δθ1 is the rotation angle of the second link 28 around the support 32, and
Δθ2 is the rotation angle of the first link 14 with respect to the second link 28, and Δθ
3 is the rotation angle of the workpiece 12 with respect to the support 32, R1 is the second
Is the radius of the pulley 22 and R3 is the radius of the first pulley 20.
Further, if it is desired to maintain the orientation of the workpiece 12, ie Δθ3 at 0, then Equation 1 becomes:

R1 / R3 = (Δθ2 + Δθ1) / (Δθ2) Equation 2 or Δθ1 / Δθ2 = ((R1 / R3) −1) Equation 3 Equations 1 and 2 for obtaining the rotation ratio and The use of 3 makes it possible to support a plurality of forms of the robot arm.

Different forms of the robot arm can be obtained by changing the lengths of the first link 14 and the second link 28. Further, the second link 28 can be composed of a plurality of rotatably sequentially connected links. Multiple rotatably connected links could form multiple configurations of robot arm assembly 10 to accommodate different applications.

In practice, the ratio of the radius of the first pulley 20 to the radius of the second pulley 22 is such that the rotation angle Δθ3 of the workpiece with respect to the support 32 is at least 1 in the working space of the robot arm assembly 10. It is usually sized to be zero at one position. In operation, the robot arm assembly 10 can be programmed to vary the rotation of the workpiece 12 according to Equation 1 to control the rotation of the workpiece 12 and minimize cycle time.

A motor 36 mounted on the pulley 22 and the second link 28 and mounted on the first link 14 facilitates rotation of the first link 14 with respect to the second link 28 and the pulley 22. To do. It will be appreciated that other means known in the art may be employed to rotate the first link 14 with respect to the second link 28.

In the standard robot arm assembly 10, a motor 36 drives a robot flange disposed within the wrist housing and capable of mounting the first link 14. The pulley 22 is fixed to the wrist housing.

The present invention is directed to a method of moving a workpiece 12 by a tool 16 rotatably mounted on a first end 16 of a first link 14, and to a second end 18 of the first link 14. A method of moving the pivotally connected second link 28 is included. With reference to FIGS. 3 and 4, the method includes rotating the second link 28 about the support 32, rotating the first link 14 with respect to the second link 28, and with respect to the first link 14. At a predetermined rotation ratio of the second link 28, the first link 14
Rotating the tool 26 with respect to. The marker 13, which is shown in detail in FIG. 4 and is arranged on the workpiece 12, follows the change in orientation of the workpiece 12 through the rotation angle Δθ3.

Further included is coupling the rotation of the second link 28 with respect to the first link 14 to the rotation of the tool 26 with respect to the first link 14. By coupling the rotation of the tool 26 to the rotation of the first link 14 at a predetermined ratio, the tool 26 is aligned with the second link 28 as the second link 28 rotates with respect to the first link 14. I will rotate.

Another method of moving the workpiece with the robot arm assembly 10 is to form the rotary coupling 24 such that the tool 26 and the second link 28 rotate with respect to the support 32 at a predetermined rotation ratio, second. Supports link 28 at angle 32 around support 32
The step of rotating the first link 14 by the motor 36 so that the center of gravity of the workpiece 12 shifts along a predetermined path, and the step of rotating the workpiece at a minimum rotation angle Δθ3. The first link 1 with respect to the second link 28
4 includes adjusting the rotation angle Δθ2 of 4. Additionally, rotating the second link 28, rotating the first link 14, and adjusting the rotation angle Δθ2 of the first link 14 with respect to the second link 28 move the workpiece 12. It is a part of the robot operation software program.

Having described the invention graphically, it will be appreciated that the terminology used is intended to be descriptive in nature, rather than limiting.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. The invention may be practiced other than as specifically described within the scope of the appended claims,
What is prior art there precedes the novelty described in the "Characterization" section. This novelty means that it is described particularly clearly in the "characterization" section, whereas the preceding entries merely describe the well-known and old combinations in which the present invention resides.

These preceding statements are intended to cover any combination where the novelty of the invention has utility. In addition, reference numerals are for convenience only and are not to be understood as limiting in any way.

[Brief description of drawings]

[Figure 1]   It is a side view of a robot arm assembly.

[Fig. 2]     It is a top view of a robot arm assembly.

FIG. 3 is a process diagram of the steps required to move a workpiece between work terminals using the robot arm assembly.

FIG. 4 is a plan view of a robot arm assembly illustrating the angular relationship between the components of the robot arm.

─────────────────────────────────────────────────── ─── [Continued summary] 8) When rotating with respect to reference plane A, the tool (2 6) Limit the rotation of the workpiece (12). Second Rotate the first link (14) with respect to the link (28) It is a robot to move the work piece (12). This is the role of the operating software program.

Claims (16)

[Claims] 1. A robot arm assembly (10) for moving a workpiece (12).
), A first link (14) having a first end (16) and a second end (18), and the first end (16) of the first link (14). )) (2)
6), a first end (30) rotatably mounted on a support (32) and said first
A second link (28) having a second end (34) rotatably connected to said link (14), a first end connected to said tool (26) and said second A coupling (24) with a second end fixed with respect to the link (28), said coupling with said second link (28) so as to limit rotation of said tool (26) with respect to reference plane A. Disposed between a tool (26) such that the second link (28) rotates with respect to the support (32), and the first link (14) comprises the second link (). With respect to the coupling (24) and the second link (28), the orientation of the workpiece (12) with respect to the reference plane A is maintained when rotating the workpiece (12) with respect to (28). And the second link (28 Independent of, and independent of the coupling (24) for securing the first link (14) to the second link (28) and to the first link (14). A motor (36) functionally mounted to the robot arm assembly (10). 2. A first pulley (20) rotatably mounted to the first end (16) of the first link (14) at the first end of the coupling (24). ) And the second end of the coupling is disposed adjacent to the second end (18) of the first link (14).
22. The assembly of claim 1, comprising 22), wherein the second pulley (22) is secured to the second link (28). 3. The first pulley (20) and the second pulley (22).
The assembly of claim 2, wherein the radii have different radii such that a predetermined turn ratio is formed between the first pulley (20) and the second pulley (22). 4. The pulleys (20, 22) are disc-shaped with a peripheral portion, and the coupling (24) is a seamless belt (24) provided around the pulleys (20, 22). An assembly according to claim 2, comprising: 5. A set according to claim 4, wherein the pulleys (20, 22) have a grooved peripheral edge and the seamless belt (24) is disposed within the grooved peripheral edge. Three-dimensional. 6. The first pulley (20) and the second pulley (22).
The ratio between and is determined by an equation, which is Δθ3 = Δθ2 (1-
(R1 / R3)) + (Δθ1), where Δθ1 is the support (32)
Is the rotation angle of the second link (28) around, Δθ2 is the rotation angle of the first link (14) with respect to the second link (28), and Δθ3 is the The angle of rotation of said workpiece (12) with respect to the support (32), R1
The assembly of claim 3, wherein is the radius of the second pulley (22) and R3 is the radius of the first pulley (20). 7. The first pulley (20) and the second pulley (22)
The assembly of claim 3, wherein the ratio between and is 2 to 1. 8. The assembly of claim 1, wherein the second link (28) comprises a plurality of rotatably sequentially connected links. 9. (Delete). 10. A support (32), a first link (14), rotatably mounted on a first end (16) of the first link (14) and a workpiece (1).
A tool (26) bearing 2), a second link (rotatably mounted on a support (32) and rotatably connected to a second end (18) of the first link (14). 28), a rotary coupling arranged between the second link (28) and the tool (26) for connecting the tool (26) and the second link (28) so as to rotate at a predetermined ratio. , And a method of moving a workpiece (12) with a robot arm assembly (10) having a motor (36) mounted on a second link (28) that rotates a first link (14), Rotating the second link (28) about the support (32), the first link (14) with respect to the second link (28) and the second link (28).
28) to rotate independently of the coupling (24)
Rotating the link (14) with a motor (36) and a second link so that the orientation of the workpiece (12) is maintained with respect to the reference plane A when the workpiece (12) is moved. Rotating the tool (26) with respect to the first link (14) at a predetermined ratio with respect to the rotation of (28). 11. Rotation of the second link (28) so that the tool (26) rotates at a predetermined ratio and in line with the rotation of the second link (28).
Method according to claim 10, further comprising the step of coupling with rotation of the tool (26) with respect to 14). 12. Rotating the tool (26) at a predetermined ratio with respect to the first link (14) is further defined by determining the predetermined ratio according to an equation,
The equation is Δθ3 = Δθ2 (1- (R1 / R3)) + (Δθ1), where Δθ1 is the rotation of the second link (28) around the support (32). Is the angle and Δθ2 is the first link () with respect to the second link (28).
14) is the rotation angle, Δθ3 is the rotation angle of the workpiece (12) with respect to the support (32), R1 is the radius of the second pulley (22), and R3 is The method of claim 10, wherein the radius of the first pulley (20). 13. Rotating the tool (26) at a predetermined ratio with respect to the first link (14) comprises a tool (26) at a ratio of 2 to 1 with respect to rotation of the second link (28).
11. The method of claim 10, further defined by rotating). 14. (Deleted) 15. The support (32), the first link (14), the second link (28), the end (3) of the second link (28) rotating the first link (14).
Workpiece (12) with a robot arm assembly (10) having a motor (36) arranged in 4) and a tool (26) for supporting the workpiece (12).
Forming a rotary coupling (24) such that the tool (26) and the second link (28) rotate with respect to the support (32) at a predetermined rotation ratio. And rotating the link (28) of the workpiece (12) around the support (32) by an angle Δθ1 so that the center of gravity of the workpiece (12) moves along a predetermined path.
Only with respect to the second link (28), independently of the second link (28), and independent of the coupling (24), the first link (1).
4) rotating, and the rotation angle Δθ2 of the first link (14) with respect to the second link (28) such that the rotation angle Δθ3 of the workpiece (12) is minimized.
In the method including the step of adjusting, Δθ1 is the second around the support (32).
Is the angle of rotation of the link (28), Δθ2 is the angle of rotation of the first link (14) with respect to the second link (28), and Δθ3 is the workpiece () with respect to the support (32). The method which is the rotation angle of 12). 16. Rotating the second link (28), the first link (
14) rotating the stage, and with respect to the second link (28) the first link (1
Adjusting the rotation angle Δθ2 of 4) is part of a robot manipulation software program that moves the workpiece (12) while maintaining the orientation of the workpiece (12) with respect to the reference plane A. The method described.