A passive compliance device for the end of a robot

Abstract

The present invention relates to a passive compliance device for a robot end, comprising: a floating end for connecting with an end tool, a limiting shaft being provided on the floating end, the lower end of the limiting shaft being fixedly connected to the middle part of the upper end of the floating end; an upper fixed end for connecting with a robot, an axial limiting mechanism being provided on the upper fixed end, the lower end of the axial limiting mechanism being in contact with the upper end of the limiting shaft; a lower fixed end, the lower fixed end being sleeved on the outer side of the upper end of the limiting shaft, the upper wall of the lower fixed end being fixedly connected to the lower wall of the upper fixed end, a radial limiting mechanism being provided between the lower fixed end and the limiting shaft, and a plurality of pre-tightening limiting mechanisms being provided between the lower fixed end and the floating end along the circumference of the limiting shaft. The present invention can respectively lock the limiting shaft in the axial and radial directions through the pre-tightening limiting mechanism, the axial limiting mechanism and the radial limiting mechanism, so as to avoid rigid collision between the end tool and the robot, and play the role of buffering and passive compensation.

Description

Technical Field

[0001] The invention relates to the technical field of robots, and in particular to a passive compliance device at the end of a robot. Background Art

[0002] With the rapid development of industrial automation, industrial robots are widely used in production and manufacturing. When sorting, assembling, grinding and other operations, the end fixture will inevitably come into direct contact with the workpiece. If both the working tool and the working object are very rigid and collision is not allowed, the end of the robot needs to be flexible. In addition, it is difficult to achieve collision-free contact by position control at the moment when the working tool and the object come into contact with each other. At this time, the robot is required to have a certain degree of flexibility so that the working tool and the working object can gradually achieve flexible contact or "soft landing". If a passive compliant wrist is installed between the end flange of the robot and the fixture, collision can be effectively avoided.

[0003] During the robot automatic assembly process, there may be deviations in the workpiece or high requirements for the robot's repeated positioning accuracy. If rigid assembly is used, the workpiece and tool will be damaged, or the robot will alarm and stop, affecting production efficiency. Using a robot end flexible device for tool transfer can effectively solve such problems. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a robot end passive compliance device that plays a role of buffering and passive compensation between the robot and the end tool, so as to solve at least one of the above technical problems.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] A passive compliance device at the end of a robot, comprising:

[0007] A floating end connected to the end tool, wherein the floating end is provided with a limit shaft, and the lower end of the limit shaft is fixedly connected to the middle part of the upper end of the floating end;

[0008] An upper fixed end connected to the robot, wherein an axial limiting mechanism is provided on the upper fixed end, and a lower end of the axial limiting mechanism abuts against an upper end of the limiting shaft;

[0009] The lower fixed end is sleeved on the outer side of the upper end of the limiting shaft, the upper wall of the lower fixed end is fixedly connected to the upper wall of the lower fixed end, a radial limiting mechanism is provided between the lower fixed end and the limiting shaft, and a plurality of pre-tightening limiting mechanisms are provided between the lower fixed end and the floating end along the circumference of the limiting shaft.

[0010] The beneficial effects of the present invention are: the present application can play a role of buffering and passive compensation between the end tool and the robot; in the present application, the axial and radial directions of the limit shaft can be locked respectively through the axial limiting mechanism and the radial limiting mechanism, which can avoid rigid collision between the end tool and the robot, and flexibly realize the "soft landing" between the end tool and the robot; the pre-tightening limit mechanism can enhance the stability between the lower fixed end and the floating end.

[0011] Based on the above technical solution, the present invention can also be improved as follows.

[0012] Furthermore, the radial limiting mechanism includes an annular cylinder and a plurality of piston tops, the annular inner side of the annular cylinder is provided with piston holes corresponding to the piston tops one by one, one end of the piston top extends into the piston hole and is slidably connected to the piston hole, the other end of the piston top passes through and extends out of the piston hole and abuts against the side wall of the limiting shaft, the lower fixed end is provided with an inner hole, the outer edge of the annular cylinder is transitionally matched with the inner hole of the lower fixed end, a first air connecting head is provided on one side of the lower fixed end, and one end of the first air connecting head is connected to the annular cylinder.

[0013] The beneficial effect of adopting the above further solution is that the radial limiting mechanism can lock the circumference of the limiting shaft, and the compressibility of the gas can be used to avoid the swing of the limiting shaft.

[0014] Furthermore, the axial limiting mechanism includes a cylinder body, a cylinder head, a piston and a locking shaft. The cylinder body is provided with an air groove opening downward, the cylinder head is sealed at the opening of the air groove and fixedly connected to the cylinder body, the piston is arranged in the air groove and is slidably connected to the side wall of the air groove, one end of the locking shaft is slidably connected to the other end of the piston, the other end of the locking shaft passes through the cylinder head and abuts against the upper end surface of the limiting shaft, a second air connecting head is provided on the side of the upper fixed end, and one end of the second air connecting head is connected to the air groove of the cylinder body.

[0015] The beneficial effect of adopting the above further solution is that the locking shaft of the axial limiting mechanism abuts against the upper end surface of the limiting shaft, which can effectively limit the circumferential movement of the limiting shaft.

[0016] Furthermore, the piston includes an upper piston part, a lower piston part and a sealing ring, the sealing ring is arranged between the upper piston part and the lower piston part, the upper piston part and the lower piston part are connected to the upper end of the locking shaft through bolts, and the outer edge of the sealing ring is slidably connected to the inner wall of the air groove.

[0017] The beneficial effect of adopting the above further solution is that the sealing ring can improve the sealing of the piston, and at the same time, the upper piston part, the lower piston part and the locking shaft are connected as a whole by screws to improve the locking effect of the locking shaft on the upper end of the limit shaft.

[0018] Furthermore, a first attitude sensor and a circuit board are provided on the upper fixed end, and a second attitude sensor is provided on the floating end. Both the first attitude sensor and the second attitude sensor are electrically connected to the circuit board.

[0019] The beneficial effect of adopting the above further solution is that the posture sensor can obtain the posture data of the upper fixed end and the floating end respectively, and send them to the robot, which can ensure that the device is not damaged.

[0020] Furthermore, a light strip is provided on the circumferential side wall of the upper fixed end, and the light strip is electrically connected to the circuit board.

[0021] The beneficial effect of adopting the above further solution is that the light strip can display the relative position between the floating end and the upper fixed end, which is convenient for manual judgment and operation and protects the end effector and the robot from damage.

[0022] Furthermore, the pre-tightening limit mechanism includes a pre-tightening bolt and a spring, the spring is sleeved on the outside of the pre-tightening bolt, the upper end of the spring is fixedly connected to the lower fixed end, the lower end of the spring is fixedly connected to the floating end, and the upper end of the pre-tightening bolt is fixedly connected to the upper fixed end.

[0023] The beneficial effect of adopting the above further scheme is that the spring of the preload limit mechanism can drive the floating end and the upper fixed end to be in a normal working state, which can reduce the changes between the floating end and the fixed end caused by rigid contact, so that the floating end and the fixed end are in a normal working state.

[0024] Furthermore, the spring is a conical spring.

[0025] The beneficial effect of adopting the above further solution is that the tower-shaped spring can not only reduce the effect along the axial direction of the pre-tightening bolt, but also reduce the swing effect caused by the swing of the floating end and the fixed end bracket.

[0026] Furthermore, the floating end includes a shell and a floating flange plate, the floating flange plate is arranged on the lower side of the shell and fixedly connected to the shell, a limiting groove is provided on the shell, and the lower end of the pre-tightening bolt extends into the limiting groove and is slidably connected to the limiting groove.

[0027] The beneficial effect of adopting the above further solution is that the limiting groove can limit the lower end of the locking bolt, thereby improving the stability between the fixed end and the floating shell.

[0028] Furthermore, a limiting portion is provided at the lower end of the pre-tightening bolt, a conical bushing is sleeved on the lower end of the pre-tightening bolt, the conical bushing is interference fit with the limiting groove, and the limiting portion is interference fit with the conical bushing.

[0029] The beneficial effect of adopting the above further solution is that the tapered bushing cooperates with the limiting portion to limit the line segment of the pre-tightening bolt, thereby maintaining the stability of the connection between the floating end and the fixed end. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the structure of the present invention;

[0031] Figure 2 It is a main cross-sectional view of the structure of the present invention;

[0032] Figure 3 is a top sectional view of the lower fixed end of the present invention;

[0033] Figure 4 It is a top sectional view of the floating shell of the present invention.

[0034] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0035] 1. Upper fixed end, 2. Lower fixed end, 3. First posture sensor, 4. Axial limiting mechanism, 401. Cylinder body, 402. Cylinder head, 403. Piston, 4031. Upper piston part, 4032. Lower piston part, 4033. Sealing ring, 404. Locking shaft, 405. Second air connection head, 5. Light strip, 6. Radial limiting mechanism, 601. Annular cylinder, 602. Piston top, 603. First air connection head, 7. Floating end, 701. Floating shell, 702. Floating flange plate, 703. Limiting groove, 704. Conical bushing, 8. Pre-tightening limiting mechanism, 801. Pre-tightening bolt, 802. Spring, 803. Limiting part, 9. Limiting shaft, 10. Second posture sensor, 11. Circuit board. DETAILED DESCRIPTION

[0036] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0037] Example

[0038] like Figure 1 As shown, a passive compliance device of a robot end of the present invention comprises: a floating end 7 for connecting with an end tool, a limiting shaft 9 is provided on the floating end 7, and the lower end of the limiting shaft 9 is fixedly connected with the middle part of the upper end of the floating end 7; an upper fixed end 1 for connecting with the robot, an axial limiting mechanism 4 is provided on the upper fixed end 1, and the lower end of the axial limiting mechanism 4 abuts against the upper end of the limiting shaft 9; a lower fixed end 2, the lower fixed end 2 is sleeved on the outer side of the upper end of the limiting shaft 9, the upper wall of the lower fixed end 2 is fixedly connected with the lower wall of the upper fixed end 1, a radial limiting mechanism 6 is provided between the lower fixed end 2 and the limiting shaft 9, and a plurality of pre-tightening limiting mechanisms 8 are provided between the lower fixed end 2 and the floating end 7 along the circumference of the limiting shaft 9.

[0039] The radial limiting mechanism 6 includes an annular cylinder 601 and a plurality of piston tops 602. The inner side of the annular ring of the annular cylinder 601 is provided with piston holes corresponding to the piston tops 602 one by one. One end of the piston top 602 extends into the piston hole and is slidably connected with the piston hole. The other end of the piston top 602 passes through and extends out of the piston hole to abut against the side wall of the limiting shaft 9. The lower fixed end 2 is provided with an inner hole. The outer edge of the annular cylinder 601 is transitionally matched with the inner hole of the lower fixed end 2. One side of the lower fixed end 2 is provided with a first An air connecting head 603, one end of the first air connecting head 603 is connected to the annular cylinder 601, an annular air duct is provided in the annular cylinder 601, one end of the piston hole is connected to the air duct, and the air duct is connected to the first air connecting head 603; the piston top 602 is cylindrical, the axis of the piston hole coincides with the radial direction of the limiting shaft 9, the piston top 602 moves along the piston hole, and one end thereof approaches and abuts against the side wall of the limiting shaft 9 to lock the limiting shaft 9; preferably, six piston tops 602 are provided in the present application.

[0040] The axial limiting mechanism 4 includes a cylinder body 401, a cylinder cover 402, a piston 403 and a locking shaft 404. The cylinder body 401 is provided with an air groove opening downward, the cylinder cover 402 is sealed at the opening of the air groove and is fixedly connected to the cylinder body 401, the piston 403 is arranged in the air groove and is slidably connected to the side wall of the air groove, one end of the locking shaft 404 is slidably connected to the other end of the piston, and the other end of the locking shaft 404 passes through the cylinder cover 402 and abuts against the upper end surface of the limiting shaft 9. A second air connector 405 is provided on the side of the upper fixed end 1, and one end of the second air connector 405 is connected to the air groove of the cylinder body 401.

[0041] The piston 403 includes an upper piston portion 4031, a lower piston portion 4032 and a sealing ring 4033. The sealing ring 4033 is arranged between the upper piston portion 4031 and the lower piston portion 4032. The upper piston portion 4031 and the lower piston portion 4032 are connected to the upper end of the locking shaft 404 through bolts, and the outer edge of the sealing ring 4033 is slidably connected to the inner wall of the air groove.

[0042] A first posture sensor 3 and a circuit board 11 are provided on the upper fixed end 1, and a second posture sensor 10 is provided on the floating end 7. The first posture sensor 3 and the second posture sensor 10 are both electrically connected to the circuit board 11; the models of the first posture sensor and the second posture sensor are both WT901C485; a first mounting threaded hole for connecting to the robot is provided on the upper end wall surface of the upper fixed end 2.

[0043] A light strip 5 is provided on the circumferential side wall of the upper fixed end 1, and the light strip 5 is electrically connected to the circuit board 11. The circuit board 11 is provided with a detection circuit for collecting the first posture sensor 3 and the second posture sensor 10, and is also provided with a chip writing posture judgment algorithm, which makes real-time judgment on the posture signal of the detection circuit and sends the signal to the robot controller and the light strip 5; when the floating end 7 reaches the maximum limit angle, the light strip 5 displays red, which means early warning or alarm. When it is in a locked state, the light strip 5 displays green. When it is in a floating state, the light strip 5 displays yellow.

[0044] The pre-tightening limit mechanism 8 includes a pre-tightening bolt 801 and a spring 802. The spring 802 is sleeved on the outside of the pre-tightening bolt 801. The upper end of the spring 802 is fixedly connected to the lower fixed end 2. The lower end of the spring 802 is fixedly connected to the floating end 7. The upper end of the pre-tightening bolt 801 is threadedly fixedly connected to the upper fixed end 1.

[0045] Spring 802 is a tower-shaped spring, and an inner concave hole is provided on the side of the floating end 7 facing the lower fixed end 2. The large diameter end of the tower-shaped spring extends into the inner concave hole and is fixedly connected to the bottom wall of the inner concave hole, and the small diameter end of the tower-shaped spring is fixedly connected to the lower wall of the lower fixed end 2. When the tower-shaped spring is in a working state, when the floating end 7 is subjected to external force, the tower-shaped spring is compressed, which plays a role of buffering and passive compensation.

[0046] The floating end 7 includes a floating shell 701 and a floating flange plate 702. The floating flange plate 702 is arranged on the lower side of the floating shell 701 and is fixedly connected to the floating shell 701. A limiting groove 703 is provided on the floating shell 701. The lower end of the pre-tightening bolt 801 extends into the limiting groove 703 and is slidably connected to the limiting groove 703. The floating flange plate 702 is provided with a second mounting threaded hole for connecting to the end tool.

[0047] A limiting portion 803 is provided at the lower end of the pre-tightening bolt 801, and a conical bushing 704 is sleeved on the lower end of the pre-tightening bolt 801. The conical bushing 704 has an interference fit with the inner wall of the limiting groove 703, and the limiting portion 803 has an interference fit with the conical bushing 704; the limiting portion 803 is truncated cone-shaped, and a conical hole is provided inside the conical bushing 704 to cooperate with the side wall of the limiting portion 803.

[0048] When the present invention is locked during operation: the cylinder body 401 is connected to the compressed air source through the second air inlet 405, and the piston 403 drives the lower end of the locking shaft 404 to be pressed against the upper end surface of the limiting shaft 9 under the action of air pressure, so that the limiting portion 803 of the pre-tightening bolt 801 is locked at the opening of the limiting groove 703 through the tapered bushing 704; the first air inlet 603 is connected to the air source, so that the six piston tops 602 move toward the limiting shaft 9, and one end presses the side wall of the limiting shaft 9, so that the axial and circumferential directions of the limiting shaft 9 are locked, and when the end tool is installed, the rigid collision of the end tool on the robot can be reduced; the first posture sensor 3 and the second posture sensor 10 respectively send posture signals to the circuit board 11, and after comparison, the relative position of the floating end 7 and the fixed end is determined, which can protect the end actuator and the robot from damage, and the light strip 5 is used to display the working status of the present application, which is convenient for manual judgment and operation.

[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A passive compliance device at the end of a robot, characterized in that: include: A floating end (7) for connecting to an end tool, wherein a limiting shaft (9) is provided on the floating end (7), and the lower end of the limiting shaft (9) is fixedly connected to the middle part of the upper end of the floating end (7); An upper fixed end (1) for connecting to the robot, the upper fixed end (1) being provided with an axial limiting mechanism (4), the lower end of the axial limiting mechanism (4) being in contact with the upper end of the limiting shaft (9); A lower fixed end (2), the lower fixed end (2) is sleeved on the outer side of the upper end of the limiting shaft (9), the upper wall of the lower fixed end (2) is fixedly connected to the lower wall of the upper fixed end (1), a radial limiting mechanism (6) is provided between the lower fixed end (2) and the limiting shaft (9), and a plurality of pre-tightening limiting mechanisms (8) are provided between the lower fixed end (2) and the floating end (7) along the circumference of the limiting shaft (9); The radial limiting mechanism (6) comprises an annular cylinder (601) and a plurality of piston tops (602); the inner side of the annular ring of the annular cylinder (601) is provided with piston holes corresponding to the piston tops (602); one end of the piston top (602) extends into the piston hole and is slidably connected to the piston hole; the other end of the piston top (602) passes through and extends out of the piston hole to abut against the side wall of the limiting shaft (9); the lower fixed end (2) is provided with an inner hole; the outer edge of the annular cylinder (601) is transitionally matched with the inner hole of the lower fixed end (2); a first air connection head (603) is provided on one side of the lower fixed end (2); one end of the first air connection head (603) is connected to the annular cylinder (601); The upper fixed end (1) is provided with a first posture sensor (3) and a circuit board (11), the floating end (7) is provided with a second posture sensor (10), and the first posture sensor (3) and the second posture sensor (10) are both electrically connected to the circuit board (11).

2. A robot end passive compliance device according to claim 1, characterized in that: The axial limiting mechanism (4) comprises a cylinder body (401), a cylinder cover (402), a piston (403) and a locking shaft (404); the cylinder body (401) is provided with an air groove opening downward; the cylinder cover (402) is sealed at the opening of the air groove and is fixedly connected to the cylinder body (401); the piston (403) is arranged in the air groove and is slidably connected to the side wall of the air groove; one end of the locking shaft (404) is slidably connected to the other end of the piston; the other end of the locking shaft (404) passes through the cylinder cover (402) and abuts against the upper end surface of the limiting shaft (9); a second air connection head (405) is provided on the side surface of the upper fixed end (1); one end of the second air connection head (405) is connected to the air groove of the cylinder body (401).

3. A robot end passive compliance device according to claim 2, characterized in that: The piston (403) comprises an upper piston portion (4031), a lower piston portion (4032) and a sealing ring (4033), wherein the sealing ring (4033) is arranged between the upper piston portion (4031) and the lower piston portion (4032), the upper piston portion (4031) and the lower piston portion (4032) are connected to the upper end of the locking shaft (404) via bolts, and the outer edge of the sealing ring (4033) is slidably connected to the inner wall of the air groove.

4. A robot end passive compliance device according to claim 1, characterized in that: A light strip (5) is provided on the circumferential side wall of the upper fixed end (1), and the light strip (5) is electrically connected to the circuit board (11).

5. A robot end passive compliance device according to any one of claims 1 to 4, characterized in that: The pre-tightening and limiting mechanism (8) comprises a pre-tightening bolt (801) and a spring (802), wherein the spring (802) is sleeved on the outside of the pre-tightening bolt (801), the upper end of the spring (802) is fixedly connected to the lower fixed end (2), the lower end of the spring (802) is fixedly connected to the floating end (7), and the upper end of the pre-tightening bolt (801) is threadedly fixedly connected to the upper fixed end (1).

6. A robot end passive compliance device according to claim 5, characterized in that: The spring (802) is a conical spring.

7. A robot end passive compliance device according to claim 5, characterized in that: The floating end (7) comprises a floating shell (701) and a floating flange plate (702); the floating flange plate (702) is arranged on the lower side of the floating shell (701) and is fixedly connected to the floating shell (701); a limiting groove (703) is provided on the floating shell (701); the lower end of the pre-tightening bolt (801) extends into the limiting groove (703) and is slidably connected to the limiting groove (703).

8. A robot end passive compliance device according to claim 7, characterized in that: The lower end of the pre-tightening bolt (801) is provided with a limiting portion (803), and the lower end of the pre-tightening bolt (801) is sleeved with a conical bushing (704), the conical bushing (704) and the inner wall of the limiting groove (703) are interference fit, and the limiting portion (803) and the conical bushing (704) are interference fit.

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