Multi-axis force sensor
By adopting a vertically cross-shaped elastic cross beam and longitudinal beam design in a multi-dimensional force sensor, combined with a symmetrical hole structure, the problems of high stiffness, low sensitivity and difficult processing in the prior art are solved, and small size and solution are achieved A multi-dimensional force sensor with good coupling and high sensitivity, suitable for industrial robots.
Patent Information
- Application Number
- CN202011426950.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2020-12-09
- Publication Date
- 2024-12-13
- Estimated Expiration
- 2040-12-09
AI Technical Summary
In the application of existing multi-dimensional force sensors in the field of industrial robots, it is difficult to take into account the requirements of small size, good decoupling, high sensitivity and simple structure and easy processing. The design of traditional cross beams is relatively stiff and low sensitivity, and the gap between serpentine structure beams is small and difficult to achieve. Processing, the design of larger double cross beams has poor decoupling.
Design a multi-dimensional force sensor, using elastic cross beams and longitudinal beams arranged vertically between the external frame and the internal platform, the elastic beams have a cross-shaped cross-section, and the openings of the cross beams and longitudinal beams are symmetrically arranged to form a symmetrical plate-shaped beam Structure, easy to process and decouple, increase the position of the strain gauge patch, and facilitates the improvement of detection sensitivity.
It realizes a multi-dimensional force sensor with small size, good decoupling and high sensitivity. It has a simple structure and is easy to process. It is suitable for industrial robots and improves the detection sensitivity and fatigue resistance of the sensor.
Smart Images
Figure CN114608739B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of sensor technology, and in particular to a multi-dimensional force sensor for measuring force / torque. Background Art
[0002] With the continuous development of robot technology, the demand for force control at the end of the robot actuator is also increasing. Multi-dimensional force sensors can detect the magnitude of force and torque in space, and can meet the force control needs of the robot end to enrich the types of work that the robot can perform. There are already three-dimensional force sensors and six-dimensional force sensors in the existing technology, but for the application in the field of industrial robots, the performance requirements of sensors are higher, such as small size, high sensitivity, good rigidity, etc.
[0003] The patent with application number CN201010577466 provides a sensor design using a double cross beam, which reduces the inter-dimensional coupling and improves the sensor accuracy, but the sensor is large in size and is not suitable for industrial robots; the patent with application number CN201620008204 provides a six-dimensional force sensor with a more compact structure, which is small in overall size and low in height, but has the characteristics of a small range. The patent with application number CN201910064852 provides a force sensor with a serpentine structure beam, which improves the design of the traditional cross beam and improves the sensitivity of the elastic body when it is stressed, but when the overall size of the force sensor is small, the gap of the serpentine structure beam is small and difficult to process and manufacture. The patent with application number CN201910524444 provides a six-dimensional force sensor for industrial sites, which adopts the traditional cross beam knot design and sets a limit structure, and has a certain overload resistance, but the traditional cross beam has a large stiffness and the sensor has a low sensitivity, which is difficult to apply to the end of the robot actuator.
[0004] Therefore, it is necessary to design a multi-dimensional force sensor with small size, good decoupling, good sensitivity, simple structure and easy processing. Summary of the invention
[0005] In view of this, an object of the present invention is to provide a multi-dimensional force sensor with small size, good decoupling, good sensitivity, simple structure and easy processing.
[0006] The present invention can adopt the following technical solution: a multi-dimensional force sensor, including an external frame, an internal platform and a plurality of elastic beams radially distributed between the external frame and the internal platform, the elastic beams including elastic cross beams and elastic longitudinal beams arranged vertically and crosswise, and the two ends of the elastic cross beams and elastic longitudinal beams are respectively connected to the external frame and the internal platform.
[0007] Furthermore, the elastic beam has a cross-shaped cross section.
[0008] Furthermore, the elastic cross beam includes openings located on different sides of the elastic longitudinal beam.
[0009] Furthermore, the openings of the elastic cross beam are symmetrically arranged relative to the elastic longitudinal beam.
[0010] Furthermore, the elastic cross beam and the elastic longitudinal beam are plate-shaped beams respectively, and the elastic cross beam and the elastic longitudinal beam are symmetrically arranged with respect to each other.
[0011] Furthermore, the plate-like beam includes a large head end and a small head end, and the plate-like beam gradually decreases from the large head end to the small head end. The large head end is connected to the internal platform, and the small head end is connected to the external frame.
[0012] Furthermore, the elastic cross beam and the elastic longitudinal beam are both rectangular plate beams.
[0013] Furthermore, at least one of the elastic cross beam and the elastic longitudinal beam is a trapezoidal plate beam.
[0014] Furthermore, the number of the elastic beams is four, and the four elastic beams are distributed in a cross shape along a plane to form a cross beam.
[0015] Furthermore, the multi-dimensional force sensor includes a plurality of strain gauges, the strain gauges are symmetrically arranged on the upper and lower surfaces of the elastic cross beam, and the strain gauges are symmetrically arranged on the left and right surfaces of the elastic longitudinal beam.
[0016] Furthermore, the multi-dimensional force sensor is a six-dimensional force sensor or a three-dimensional force sensor.
[0017] Furthermore, the height of the elastic longitudinal beam does not exceed the height of the internal platform.
[0018] The present invention may also adopt the following technical solution: a robot comprises a working arm driven by an actuator to perform work, the end of the working arm comprises a connector for connecting various task tools, and the multi-dimensional force sensor described in any one of the above items is arranged in the connector.
[0019] Furthermore, the robot is an industrial robot. Preferably, the industrial robot is a collaborative robot.
[0020] Compared with the prior art, the beneficial effects of the specific implementation of the present invention are: the elastic beam of the multi-dimensional force sensor includes an elastic cross beam and an elastic longitudinal beam which are arranged perpendicular to each other and respectively connect the internal platform and the external frame. The elastic beam has good continuity, symmetrical structure, easy processing, good decoupling and good sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The above-mentioned objectives, technical solutions and beneficial effects of the present invention can be achieved through the following drawings:
[0022] Figure 1 Schematic diagram of a multi-dimensional force sensor according to an embodiment of the present invention
[0023] Figure 2 yes Figure 1 A cross-sectional view of the multi-dimensional force sensor of the embodiment shown along the BB cross-sectional line
[0024] Figure 3 is a schematic diagram of a multi-dimensional force sensor according to another embodiment of the present invention
[0025] Figure 4 yes Figure 3 A cross-sectional view of the multi-dimensional force sensor of the embodiment shown along the AA cross-sectional line
[0026] Figure 5 Schematic diagram of a multi-dimensional force sensor according to another embodiment of the present invention
[0027] Figure 6 yes Figure 5 Modified embodiment of the multi-dimensional force sensor of the illustrated embodiment
[0028] Figure 7 Schematic diagram of the position of strain gauges of a multi-dimensional force sensor according to an embodiment of the present invention
[0029] Figure 8 Schematic diagram of a robot according to an embodiment of the present invention DETAILED DESCRIPTION
[0030] In order to make the purpose, technical scheme and advantages of the present invention clearer, the scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. It should be noted that the terms "up", "down", "left", "right" and similar expressions used in this article are for illustrative purposes only and are not restrictive. The description of the orientation in this article takes the horizontal placement of the described object as the reference angle.
[0031] The present invention protects a multi-dimensional force sensor. Figure 1-Figure 7 The embodiment of the multi-dimensional force sensor 1 protected by the present invention is shown. The multi-dimensional force sensor 1 includes an external frame 10, an internal platform 20, and a plurality of elastic beams 30 radially distributed between the external frame 10 and the internal platform 20. The elastic beams 30 include elastic cross beams 31 and elastic longitudinal beams 32 arranged vertically and crosswise. The two ends of the elastic cross beams 31 and the elastic longitudinal beams 32 are connected to the external frame 10 and the internal platform 20, respectively. In one embodiment of the present invention, the reference Figure 1-Figure 2 ,in, Figure 2 yes Figure 1 The cross-sectional view of the multi-dimensional force sensor shown along the BB section line shows that the elastic cross beam 31 is arranged parallel to the horizontal plane, the elastic longitudinal beam 32 is arranged perpendicular to the horizontal plane, the elastic cross beam 31 and the elastic longitudinal beam 31 are vertically crossed, the elastic cross beam 31 divides the elastic longitudinal beam 32 into two upper and lower parts in the vertical direction, and the upper and lower parts are symmetrically arranged relative to the elastic cross beam 31, and the elastic longitudinal beam 32 divides the elastic cross beam 31 into two left and right parts in the horizontal direction, and the left and right parts are symmetrically arranged relative to the elastic longitudinal beam 32. By arranging the cross-arranged elastic cross beam 31 and the elastic longitudinal beam 32, the two ends of the elastic cross beam 31 and the elastic longitudinal beam 32 are connected to the external frame 10 and the internal platform 20 respectively, the elastic cross beam 31 and the elastic longitudinal beam 32 are continuously arranged to connect the internal platform 20 and the external frame 10 without interruption in the middle, the elastic beam 30 has no obvious mutation, no stress concentration, and good fatigue resistance. At the same time, the elastic cross beam 31 and the elastic longitudinal beam 32 extend in the horizontal direction and the vertical direction respectively, the elastic beam 30 includes a neutral axis, the positive stress value on the neutral axis is 0, the elastic cross beam 31 and the elastic longitudinal beam 32 are cross-arranged and extend in the horizontal direction and the vertical direction respectively, so that the detection of the multi-dimensional force sensor 1 is far away from the neutral axis, and the detection sensitivity is better.
[0032] The multi-dimensional force sensor 1 includes an elastic cross beam 31 and an elastic longitudinal beam 32. In one embodiment of the present invention, Figure 2 , the elastic beam 30 has a cross-shaped cross section. In another embodiment of the present invention, Figure 3 The elastic cross beam 31 includes openings located on different sides of the elastic longitudinal beam 32. Further, the openings of the elastic cross beam 31 are symmetrical along the elastic longitudinal beam 32. By setting the openings, the strain of the multi-dimensional force sensor 1 can be increased and the sensitivity of the multi-dimensional force sensor can be improved. Figure 4 , Figure 4 yes Figure 3 The cross-sectional view of the multi-dimensional force sensor of the illustrated embodiment is taken along the AA section line. The elastic beam of the multi-dimensional force sensor provided by the embodiment has a cross-shaped cross section.
[0033] The elastic beam 30 of the multi-dimensional force sensor 1 includes an elastic cross beam 31 and an elastic longitudinal beam 32. The elastic cross beam 31 is arranged parallel to the horizontal plane, and the elastic longitudinal beam 32 is arranged perpendicular to the horizontal plane. The elastic cross beam 31 and the elastic longitudinal beam 32 are plate-shaped beams respectively. The elastic cross beam 31 and the elastic longitudinal beam 32 are arranged symmetrically with each other. The symmetrical structure makes the multi-dimensional force sensor 1 have better decoupling. Further, the number of the elastic beams 30 is four, and the four elastic beams 30 are distributed in a cross shape along the horizontal plane to form a cross beam. That is, the four elastic beams 30 form a cross beam, and the elastic cross beam 31 and the elastic longitudinal beam 32 of each elastic beam 30 are perpendicular to each other, so that the multi-dimensional force sensor 1 can be completely decoupled. Within a certain range, as the height of the elastic longitudinal beam 32 increases, the sensitivity of the multi-dimensional force sensor is better. The two ends of the elastic longitudinal beam 32 are connected to the external frame 10 and the internal platform 20, and the height of the elastic longitudinal beam 32 does not exceed the height of the internal platform, so that the multi-dimensional force sensor 1 is more sensitive to detection and smaller in size.
[0034] In one embodiment of the present invention, Figure 5 , the elastic cross beam 31 and the elastic longitudinal beam 32 are respectively formed as plate-like beams, the plate-like beams include a large head end and a small head end, the plate-like beams gradually narrow from the large head end to the small head end, the large head end is connected to the internal platform 20, and the small head end is connected to the external frame 10. The size of the large head end of the plate-like beam is larger than the size of the small head end. Exemplarily, the plate-like beam is a trapezoidal plate-like beam, that is, the side where the lower bottom surface of the trapezoid is located is the large head end, and the side where the upper bottom surface of the trapezoid is located is the small head end. The elastic beam 30 with this structure increases the strain of the multi-dimensional force sensor 1, and the strain gradient is stable. At the same time, it can increase the patch position of the strain gauge, which is convenient for patching. Specifically, the elastic cross beam 31 and the elastic longitudinal beam 32 may include plate-like beams with the same structure, or the elastic cross beam 31 and the elastic longitudinal beam 32 may include plate-like beams with different structures, for example, Figure 5 As shown, the elastic cross beam 31 is a trapezoidal plate beam, and the elastic longitudinal beam 32 is a rectangular plate beam, or both the elastic cross beam 31 and the elastic longitudinal beam 32 can be trapezoidal plate beams. Figure 6 yes Figure 5 A modified embodiment, that is, the elastic cross beam 31 includes openings located on different sides of the elastic longitudinal beam 32. Specifically, the openings are symmetrically arranged relative to the elastic longitudinal beam 32. The openings are arranged on the elastic cross beam to facilitate the processing of the openings by the sensor. At the same time, the strain of the sensor can be increased and the detection sensitivity can be improved.
[0035] The multi-dimensional force sensor 1 is placed horizontally on a plane as an observation angle. At this time, the elastic cross beam of the elastic beam 30 is arranged parallel to the horizontal plane, and the elastic longitudinal beam of the elastic beam is arranged perpendicular to the horizontal plane. The multi-dimensional force sensor includes a plurality of strain gauges. The left and right surfaces of the elastic cross beam 31 can be provided with strain gauges 33, and the upper and lower surfaces of the elastic longitudinal beam 32 can be provided with strain gauges 33. Specifically, see Figure 7 , strain gauges 33 are symmetrically arranged on the upper and lower surfaces of each of the elastic cross beams, strain gauges are symmetrically arranged on the left and right surfaces of each of the elastic longitudinal beams 32, and the multi-dimensional force sensor 1 includes four elastic beams 30, and the strain gauges of the elastic beams 30 form a Wheatstone full-bridge circuit. In one embodiment of the present invention, the multi-dimensional force sensor 1 includes 24 strain gauges, and the multi-dimensional force sensor 1 is used to detect six-dimensional force information. The multi-dimensional force sensor 1 is a six-dimensional force sensor, and the strain gauges of the elastic beams form a Wheatstone full-bridge circuit. In other embodiments, by adjusting the number and installation position of the strain gauges, the multi-dimensional force sensor can be a sensor of other dimensions such as a three-dimensional sensor.
[0036] The beneficial effects of the above preferred embodiments are: the elastic beam of the multi-dimensional force sensor includes an elastic cross beam and an elastic longitudinal beam which are arranged perpendicularly and cross-sectionally and respectively connect the internal platform and the external frame. The elastic beam has good continuity, symmetrical structure, easy processing, good decoupling and good sensitivity.
[0037] The present invention is also used to provide a robot, Figure 8 The robot 6 includes a working arm 60 driven by an actuator to perform work, and the end of the working arm 60 includes a connector 70 for connecting various task tools, and the multi-dimensional force sensor described in any one of the above is arranged in the connector.
[0038] Specifically, the connector 70 is a tool flange, and the tool flange can be connected to various task tools, such as a gripper, a suction cup, etc. Specifically, the robot is an industrial robot, preferably, the robot is a collaborative robot that can perform work in collaboration with a human, and the collaborative robot can be manually taught to perform a predetermined task according to a teaching trajectory.
[0039] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.
Claims
1. A multi-dimensional force sensor, It is characterized in that It includes an external frame, an internal platform and a plurality of elastic beams radially distributed between the external frame and the internal platform, the elastic beams include elastic cross beams and elastic longitudinal beams arranged vertically and crosswise, the two ends of the elastic cross beams and elastic longitudinal beams are respectively connected to the external frame and the internal platform; the elastic cross beams and elastic longitudinal beams are respectively plate-shaped beams, and the elastic cross beams and elastic longitudinal beams are symmetrically arranged with each other; the plate-shaped beams include a large head end and a small head end, the plate-shaped beams gradually narrow from the large head end to the small head end, the large head end is connected to the internal platform, and the small head end is connected to the external frame; the number of the elastic beams is four, and the four elastic beams are cross-distributed along the plane to form a cross beam; the multi-dimensional force sensor includes a plurality of strain gauges, strain gauges are symmetrically arranged on the upper and lower surfaces of the elastic cross beams, and strain gauges are symmetrically arranged on the left and right surfaces of the elastic longitudinal beams.
2. The multi-dimensional force sensor according to claim 1, It is characterized in that The elastic beam has a cross-shaped cross section.
3. The multi-dimensional force sensor according to claim 1, It is characterized in that The elastic cross beam includes openings located on different sides of the elastic longitudinal beam.
4. The multi-dimensional force sensor according to claim 1, It is characterized in that The multi-dimensional force sensor is a six-dimensional force sensor or a three-dimensional force sensor.
5. A robot, It is characterized in that It comprises a working arm driven by an actuator to perform work, the end of the working arm comprises a connector for connecting various task tools, and the multi-dimensional force sensor according to any one of claims 1 to 4 is arranged in the connector.
6. The robot according to claim 5, It is characterized in that The robot is an industrial robot.