A cylindrical six-dimensional force sensor for sensing traction

Abstract

The present invention belongs to the field of robot teaching, and specifically discloses a cylindrical six-dimensional force sensor for sensing traction, which includes a flange column, a cylindrical elastic sensitive body, a resistance strain gauge and a seal, wherein the end of the flange column is connected to the actuator, and the top is connected to the mechanical arm; the cylindrical elastic sensitive body is sleeved on the outside of the flange column and connected to the flange column, and its upper part is a stress sensitive area, and the lower part is an external connection area, and the stress sensitive area is used to paste the resistance strain gauge, and then measure the six-dimensional traction it receives; the seal is sleeved on the outside of the cylindrical elastic sensitive body, and is used to protect the cylindrical elastic sensitive body while transmitting the six-dimensional traction acting on the seal, and the top of the seal is connected to the top of the cylindrical elastic sensitive body. The present invention can transmit the working load force of the end actuator to the mechanical arm through the series-connected flange columns, and will not generate force interference to the cylindrical elastic sensitive body, thereby realizing the decoupled measurement of traction and end execution force.

Description

Technical Field

[0001] The invention belongs to the field of robot teaching, and more specifically, relates to a cylindrical six-dimensional force sensor for sensing traction. Background Art

[0002] Direct teaching of industrial robots needs to be realized by sensing the traction force applied by the operator to the end effector of the industrial robot. Direct teaching of industrial robots does not require the operator to have knowledge of robotics technology. Ordinary workers can complete the teaching in a short time by pulling the end of the industrial robot, so it has good application prospects.

[0003] However, although many researchers have developed various direct teaching systems for industrial robots, direct teaching systems for industrial robots have not been widely used. First, due to the ambiguity and inaccuracy of human activities, the direct teaching error is large, and the existing data filtering and fitting algorithms are all filtering and teaching reproduction for specific trajectories (such as straight lines, arcs, rectangles, etc.), and it is difficult to achieve accurate reproduction of all trajectories, which makes it difficult for the direct teaching system of industrial robots to meet the requirements of accurate reproduction of complex spatial trajectories in industrial sites; second, the force sensor installed on the wrist can accurately obtain the external force acting on the end of the robot, but cannot accurately decouple the contact force and traction force in the external force, so it is difficult to directly pull the end load of the industrial robot for traction teaching when the end load is in direct contact with the operated object; third, due to the limited range of human activities, the existing direct system of industrial robots can only directly teach light-load industrial robots, but cannot teach heavy-load industrial robots with a larger range of motion.

[0004] When the robot moves in a constrained space, such as grinding, assembly, and glass cleaning, there is contact force between the robot and the environment. Existing force sensors can sense contact force, but it is difficult to measure the traction force applied by humans to the robot and the contact force between the robot and the environment at the same time. This is because it is necessary to measure the traction force (traction force is applied by humans to the outer wall of the force sensor to teach the robot) and the contact force at the same time, and the traction force and the contact force cannot interfere with each other, which is difficult to achieve with existing force sensors. Summary of the invention

[0005] In response to the above defects or improvement needs of the prior art, the present invention provides a cylindrical six-dimensional force sensor for sensing traction force, in which the two ends of a flange column are respectively connected to a robotic arm and an end effector, and the cylindrical elastic sensitive body and a seal are arranged on the outside of the flange column. This can effectively achieve the decoupling of traction force and end effector force, and is therefore particularly suitable for applications in robot teaching.

[0006] To achieve the above-mentioned purpose, the present invention proposes a cylindrical six-dimensional force sensor for sensing traction force, comprising a flange column, a cylindrical elastic sensitive body, a resistance strain gauge and a sealing member, wherein:

[0007] The flange column comprises a flange and a column connected to each other, the flange is provided with a first through hole for connecting with the end effector, and the top end of the column is provided with a second through hole for connecting with the robot arm;

[0008] The cylindrical elastic sensitive body is sleeved on the outside of the flange column and connected to the flange of the flange column through a base. The cylindrical elastic sensitive body adopts a stepped cylinder, the upper part of which is a stress sensitive area, and the lower part of which is an external connection area. The stress sensitive area is used to stick the resistance strain gauge to measure the six-dimensional traction force it receives. The external connection area is provided with an aviation plug hole for connecting to a power supply and outputting signals.

[0009] The sealing member is sleeved on the outside of the cylindrical elastic sensitive body to protect the cylindrical elastic sensitive body and transmit the six-dimensional traction force acting on the sealing member. The top end of the sealing member is connected to the top end of the cylindrical elastic sensitive body.

[0010] As a further preferred embodiment, the stress sensitive area includes a preset number of patches, and each patch is attached with two mutually perpendicular resistance strain gauges.

[0011] As a further preferred embodiment, the stress sensitive area is divided into a stress sensitive area A, a stress sensitive area B and a stress sensitive area C from top to bottom, wherein the stress sensitive area A and the stress sensitive area C are provided with four evenly distributed grooves, and the grooves on the stress sensitive area A and the stress sensitive area C are staggered.

[0012] As a further preferred embodiment, the stress sensitive area A includes four patches arranged between the grooves, which are sequentially recorded as area A1, area A2, area A3 and area A4, and the X direction is specified as the direction from area A2 to area A4, the Y direction is the direction from area A3 to area A1, and the Z direction is the vertically upward direction, wherein the resistance strain gauges in areas A1 and A3 constitute a first strain gauge full bridge for measuring the stress Fx in the X direction, and the resistance strain gauges in areas A2 and A4 constitute a second strain gauge full bridge for measuring the stress Fy in the Y direction.

[0013] As a further preferred embodiment, the stress sensitive area B is equally divided into 16 areas, which are recorded as area B1, area B2, ..., area B16 in sequence, wherein the resistance strain gauges attached to the left side of area B2, the right side of area B8, the left side of area B10 and the right side of area B16 constitute a third strain gauge full bridge for measuring the moment Mx in the X direction, the resistance strain gauges attached to the right side of area B4, the left side of area B6, the right side of area B12 and the left side of area B14 constitute a fourth strain gauge full bridge for measuring the moment My in the Y direction, and the resistance strain gauges attached to the same side of area B2, area B4, area B6, area B8, area B10, area B12, area B14 and area B16 constitute a fifth strain gauge full bridge for measuring the stress Fz in the Z direction.

[0014] As a further preference, the stress-sensitive C zone includes four patches arranged between the grooves, which are respectively recorded as zone C1, zone C2, zone C3 and zone C4, and the resistance strain gauges at the above four patches form a sixth strain full bridge for measuring the moment Mz in the Z direction.

[0015] As a further preference, the stress sensitivity of the cylindrical six-dimensional force sensor for sensing traction force is 1 με / N, and the torque sensitivity is 20 με / Nm.

[0016] As a further preferred embodiment, a winding groove is provided on the inner side of the outer connection area of ​​the cylindrical elastic sensitive body.

[0017] In general, the above technical solution conceived by the present invention has the following technical advantages compared with the prior art:

[0018] 1. The present invention uses the two ends of the flange column to connect with the robot arm and the end effector respectively, so that the working load force of the end effector is transmitted to the robot arm through the series-connected flange column structure, and no force interference is generated on the cylindrical elastic sensitive body, thereby realizing the decoupled measurement of the traction force and the end effector force. In addition, the operator can teach the robot by pulling the cylindrical six-dimensional force sensor provided by the present invention, and can realize the accurate reproduction of all trajectories, meeting the requirements for accurate reproduction of complex spatial trajectories in industrial sites. At the same time, the present invention is arranged at the front end of the end effector, has a large activity space, and is easy to operate, so it can directly teach a heavy-load industrial robot with a large range of motion;

[0019] 2. In particular, the present invention divides the stress sensitive area into zones and optimizes the patch position of the resistance strain gauge and the composition of the strain full bridge. The stress sensitive B area with severe coupling is tested by connecting multiple resistors in series. This ensures that the stress sensitivity of the cylindrical six-dimensional force sensor reaches 1με / N and the torque sensitivity reaches 20με / Nm, thereby obtaining more accurate test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a partial cross-sectional view of a cylindrical six-dimensional force sensor for sensing traction force constructed according to a preferred embodiment of the present invention;

[0021] Figure 2 is a three-dimensional exploded diagram of a cylindrical six-dimensional force sensor for sensing traction force constructed according to a preferred embodiment of the present invention;

[0022] Figure 3 is a schematic diagram of a cylindrical six-dimensional force sensor for sensing traction force constructed according to a preferred embodiment of the present invention;

[0023] Figure 4 is a schematic diagram of the expansion of the sensitive area in the preferred embodiment of the present invention;

[0024] Figure 5 It is a circuit diagram of the sixth strain gauge full bridge in a preferred embodiment of the present invention.

[0025] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0026] 1-flange column, 2-cylindrical elastic sensitive body, 3-sealing element, 4-sixth through hole, 5-fifth through hole, 6-aviation plug hole, 7-second through hole, 8-third through hole, 9-first through hole, 10-fourth through hole, 11-stress sensitive area A, 12-stress sensitive area B, 13-stress sensitive area C. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0028] like Figures 1 to 3 As shown, the embodiment of the present invention proposes a cylindrical six-dimensional force sensor for sensing traction, including a flange column 1, a cylindrical elastic sensitive body 2, a resistance strain gauge and a sealing member 3, wherein:

[0029] The flange column 1 includes a flange and a column connected to each other. The flange is provided with a first through hole 9 for connecting with the end effector. The top of the column is provided with a second through hole 7 for connecting with the robot arm. Since the working load force of the end effector is transmitted to the robot arm through the series-connected flange column 1, no force interference is generated on the stress sensitive area of ​​the cylindrical elastic sensitive body, thereby achieving decoupling of the traction force and the end execution force in the structure. At the same time, the inner ring of the flange is provided with a third through hole 8 for connecting with the cylindrical elastic sensitive body 2.

[0030] The cylindrical elastic sensitive body 2 is sleeved on the outer side of the flange column 1, and is connected with the third through hole 8 of the flange column 1 through the fourth through hole 10 of the base. The cylindrical elastic sensitive body 2 adopts a stepped cylinder, the upper part of which is a stress sensitive area, and the lower part is an external connection area. The stress sensitive area is used to stick the resistance strain gauge to measure the six-dimensional traction force it receives. The external connection area is provided with an aviation plug hole 6 for connecting the power supply and outputting the signal. At the same time, the inner side of the external connection area is provided with a winding groove;

[0031] The seal 3 is sleeved on the outside of the cylindrical elastic sensitive body 2, and is used to protect the cylindrical elastic sensitive body 2 while transmitting the six-dimensional traction force acting on the seal 3. A fifth through hole 5 is provided at the top of the seal 3, which is connected by cooperating with the sixth through hole 4 at the top of the cylindrical elastic sensitive body 2, and the lower end of the seal 3 does not contact the external connection area of ​​the cylindrical elastic sensitive body 2. When in use, the operator applies traction through the seal 3, and measures the traction through the cylindrical elastic sensitive body 2.

[0032] Further, if Figure 4 As shown, the stress sensitive area includes a preset number of patches, each of which is attached with two mutually perpendicular resistance strain gauges, and the stress sensitive area is divided into a stress sensitive A area 11, a stress sensitive B area 12 and a stress sensitive C area 13 from top to bottom, wherein the stress sensitive A area 11 and the stress sensitive C area 13 are provided with four evenly distributed grooves, and the grooves on the stress sensitive A area 11 and the stress sensitive C area 13 are staggered;

[0033] The stress sensitive A area includes four patches arranged between the slots, which are sequentially recorded as A1 area, A2 area, A3 area and A4 area. The X direction is defined as the direction from A2 area to A4 area, the Y direction is the direction from A3 area to A1 area, and the Z direction is the vertically upward direction. The resistance strain gauges in A1 area and A3 area form the first strain gauge full bridge, which is used to measure the stress Fx in the X direction. The resistance strain gauges in A2 area and A4 area form the second strain gauge full bridge, which is used to measure the stress Fy in the Y direction. There is one resistor on each bridge arm of the first strain gauge full bridge and the second strain gauge full bridge.

[0034] The stress sensitive B area is equally divided into 16 areas, which are recorded as B1 area, B2 area, ..., B16 area in sequence, wherein the resistance strain gauges attached to the left side of B2 area, the right side of B8 area, the left side of B10 area and the right side of B16 area form a third strain gauge full bridge, which is used to measure the moment Mx in the X direction, and the resistance strain gauges attached to the right side of B4 area, the left side of B6 area, the right side of B12 area and the left side of B14 area form a fourth strain gauge full bridge, which is used to measure the moment My in the Y direction, and two resistors are connected in series on each bridge arm of the third strain gauge full bridge and the fourth strain gauge full bridge, and the resistance strain gauges attached to the same side of B2 area, B4 area, B6 area, B8 area, B10 area, B12 area, B14 area and B16 area form a fifth strain gauge full bridge, which is used to measure the stress Fz in the Z direction, and four resistors are connected in series on each bridge arm of the fifth strain gauge full bridge;

[0035] like Figure 5 As shown, the stress sensitive C area includes four patches arranged between the slots, which are sequentially recorded as C1 area, C2 area, C3 area and C4 area. The resistance strain gauges at the above four patches form a sixth strain full bridge for measuring the moment Mz in the Z direction. Two resistors are connected in series on each bridge arm of the sixth strain gauge full bridge.

[0036] The arrangement of the resistance strain gauges in the above manner can ensure that the stress sensitivity of the cylindrical six-dimensional force sensor for sensing traction force is 1με / N and the torque sensitivity is 20με / Nm. In actual measurements, the traction force measurement sensitivity can reach 0.1N.

[0037] When the robot is directly taught or traction taught, the cylindrical six-dimensional force sensor provided by the present invention can be connected in series with another cylindrical six-dimensional force sensor for measuring the end load, thereby realizing simultaneous measurement of traction force and contact force.

[0038] It will be easily understood by those skilled in the art that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A cylindrical six-dimensional force sensor for sensing traction, characterized in that: It comprises a flange column (1), a cylindrical elastic sensitive body (2), a resistance strain gauge and a sealing element (3), wherein: The flange column (1) comprises a flange and a column connected to each other, the flange is provided with a first through hole (9) for connecting to an end effector, the top end of the column is provided with a second through hole (7) for connecting to a robot arm, and the inner ring of the flange is provided with a third through hole (8) for connecting to a cylindrical elastic sensitive body (2); The cylindrical elastic sensitive body (2) is sleeved on the outside of the flange column (1) and connected to the flange of the flange column (1) through a base. The cylindrical elastic sensitive body (2) adopts a stepped cylinder, the upper part of which is a stress sensitive area, and the lower part of which is an external connection area. The stress sensitive area is used to stick the resistance strain gauge to measure the six-dimensional traction force it is subjected to. The external connection area is provided with an aviation plug hole (6) for connecting a power supply and outputting a signal. The sealing member (3) is sleeved on the outer side of the cylindrical elastic sensitive body (2) and is used to protect the cylindrical elastic sensitive body (2) while transmitting the six-dimensional traction force acting on the sealing member (3). The top end of the sealing member (3) is connected to the top end of the cylindrical elastic sensitive body (2).

2. The cylindrical six-dimensional force sensor for sensing traction as claimed in claim 1, characterized in that: The stress sensitive area includes a preset number of patches, and each patch is attached with two mutually perpendicular resistance strain gauges.

3. The cylindrical six-dimensional force sensor for sensing traction as claimed in claim 1 or 2, characterized in that: The stress sensitive area is divided into a stress sensitive A area (11), a stress sensitive B area (12) and a stress sensitive C area (13) from top to bottom, wherein four evenly distributed grooves are arranged on the stress sensitive A area (11) and the stress sensitive C area (13), and the grooves on the stress sensitive A area (11) and the stress sensitive C area (13) are staggered.

4. The cylindrical six-dimensional force sensor for sensing traction as claimed in claim 3, characterized in that: The stress sensitive A area includes four patches arranged between the grooves, which are sequentially recorded as A1 area, A2 area, A3 area and A4 area. It is stipulated that the X direction is the direction from the A2 area to the A4 area, the Y direction is the direction from the A3 area to the A1 area, and the Z direction is the vertical upward direction. The resistance strain gauges in the A1 area and the A3 area constitute a first strain gauge full bridge for measuring the stress Fx in the X direction, and the resistance strain gauges in the A2 area and the A4 area constitute a second strain gauge full bridge for measuring the stress Fy in the Y direction.

5. The cylindrical six-dimensional force sensor for sensing traction as claimed in claim 4, characterized in that: The stress sensitive B area is equally divided into 16 areas, which are recorded as B1 area, B2 area, ..., B16 area in sequence, wherein the resistance strain gauges attached to the left side of the B2 area, the right side of the B8 area, the left side of the B10 area and the right side of the B16 area form a third strain gauge full bridge, which is used to measure the moment Mx in the X direction, the resistance strain gauges attached to the right side of the B4 area, the left side of the B6 area, the right side of the B12 area and the left side of the B14 area form a fourth strain gauge full bridge, which is used to measure the moment My in the Y direction, and the resistance strain gauges attached to the same side of the B2 area, the B4 area, the B6 area, the B8 area, the B10 area, the B12 area, the B14 area and the B16 area form a fifth strain gauge full bridge, which is used to measure the stress Fz in the Z direction.

6. The cylindrical six-dimensional force sensor for sensing traction as claimed in claim 5, characterized in that: The stress sensitive C area includes four patches arranged between the grooves, which are sequentially recorded as C1 area, C2 area, C3 area and C4 area. The resistance strain gauges at the above four patches form a sixth strain full bridge for measuring the moment Mz in the Z direction.

7. The cylindrical six-dimensional force sensor for sensing traction as claimed in claim 6, characterized in that: The stress sensitivity of the cylindrical six-dimensional force sensor for sensing traction force is 1 με / N, and the torque sensitivity is 20 με / Nm.

8. The cylindrical six-dimensional force sensor for sensing traction as claimed in claim 1 or 2, characterized in that: A winding groove is arranged on the inner side of the outer connection area of ​​the cylindrical elastic sensitive body (2).

Images