CN113561163B

CN113561163B - Dual-channel multidimensional force sensor and robot

Info

Publication number: CN113561163B
Application number: CN202110848936.XA
Authority: CN
Inventors: 孙恺; 任少雄
Original assignee: Suzhou Elite Robot Co Ltd
Current assignee: Suzhou Elite Robot Co Ltd
Priority date: 2021-07-27
Filing date: 2021-07-27
Publication date: 2023-06-27
Anticipated expiration: 2041-07-27
Also published as: CN113561163A

Abstract

The invention relates to a double-channel multidimensional force sensor and a robot, wherein the multidimensional force sensor comprises an outer frame, an inner platform and a plurality of elastic beams which are radially distributed between the outer frame and the inner platform, and the elastic beams comprise elastic cross beams and elastic longitudinal beams which are vertically and crosswise arranged to form a cross section; the outer frame comprises floating beams and supporting parts connected with adjacent floating beams, one ends of the elastic cross beams and the elastic longitudinal beams are connected with the floating beams, and the other ends of the elastic cross beams and the elastic longitudinal beams are connected with the inner platform; the sensor comprises two groups of strain gages for redundant detection of stress information of each dimension of the multi-dimensional force sensor, wherein the first group of strain gages are distributed on the elastic beam, and the second group of strain gages are distributed on the elastic beam and/or the floating beam. The beneficial effects of the specific embodiment of the invention are as follows: the multidimensional force sensor has good decoupling performance, high sensitivity and higher reliability of detection results.

Description

Dual-channel multidimensional force sensor and robot

Technical Field

The invention relates to the technical field of sensors, in particular to a double-channel multidimensional force sensor for measuring force/moment and a robot.

Background

With the continuous development of robotics, the force control demands on the end of the robot actuator are increasing. The multidimensional force sensor can detect the force and moment in the space, and can meet the force control requirement of the tail end of the robot so as to enrich the work types which can be executed by the robot. Three-dimensional force sensors and six-dimensional force sensors are available in the prior art, but for application in the field of industrial robots, the requirements on the performance of the sensors are higher, such as small volume, high sensitivity, good rigidity and the like.

The patent with the application number of CN201010577466 provides a sensor design adopting double cross beams, so that the inter-dimensional coupling is reduced, the sensor precision is improved, but the sensor is large in size and not suitable for being applied to an industrial robot; the patent with application number of CN201620008204 provides a six-dimensional force sensor with more compact structure, small whole volume and low height, but has the characteristic of small measuring range. The patent application number CN201910064852 provides a force sensor with a serpentine beam, which is improved in design to improve sensitivity when an elastic body is stressed, but when the overall size of the force sensor is smaller, the gap of the serpentine beam is smaller, and the force sensor is difficult to process and manufacture. The patent with the application number of CN201910524444 provides a six-dimensional force sensor applied to an industrial field, adopts a traditional cross beam structure design, is provided with a limiting structure, has certain overload carrying capacity, but the traditional cross beam has higher rigidity, the sensitivity of the sensor is lower, and the sensor is difficult to be applied to the tail end of a robot actuating mechanism.

Meanwhile, on the basis of ensuring small sensitivity and volume, when the multidimensional force sensor is applied to a precise detection scene, the stability of the operation of the multidimensional force sensor is ensured, the output data of the multidimensional force sensor is ensured to be always accurate and reliable, and adverse consequences caused by misjudgment are avoided.

Therefore, it is necessary to design a multidimensional force sensor and a robot which are small in size, good in sensitivity and high in working reliability.

Disclosure of Invention

In view of the above, the present invention aims to provide a multidimensional force sensor and a robot which are small in size, good in sensitivity and high in working reliability.

The invention adopts the following technical scheme: the multi-dimensional force sensor comprises an outer frame, an inner platform and a plurality of elastic beams radially distributed between the outer frame and the inner platform, wherein the elastic beams comprise elastic cross beams and elastic longitudinal beams which are vertically and crosswise arranged to form a cross-shaped section; the outer frame comprises floating beams and supporting parts connected with adjacent floating beams, one ends of the elastic cross beams and the elastic longitudinal beams are connected with the floating beams, and the other ends of the elastic cross beams and the elastic longitudinal beams are connected with the inner platform; the sensor comprises two groups of strain gages for redundant detection of stress information of each dimension of the multi-dimensional force sensor, wherein the first group of strain gages are distributed on the elastic beam, and the second group of strain gages are distributed on the elastic beam and/or the floating beam.

Further, at least most of the strain gages of the first group of strain gages are arranged on one side of the elastic beam close to the inner platform, so that the detection sensitivity of the sensor is improved.

Further, the sensor comprises four elastic beams forming a cross beam, and the sensor comprises four floating beams, wherein each of the four elastic beams is connected with one floating beam.

Further, the second group of strain gages are distributed on the floating beam and/or the elastic beam, and at least most of the strain gages of the second group of strain gages are arranged at positions, close to the supporting parts, at two ends of the floating beam, so that the detection sensitivity of the sensor is improved.

Further, the multi-dimensional force sensor is a six-dimensional force sensor, the sensor comprises 48 strain gauges, and the first group of strain gauges and the second group of strain gauges respectively comprise 24 strain gauges to form 6 full-bridge circuits so as to redundantly detect six-dimensional stress of the six-dimensional force sensor.

Further, the elastic cross beam, the elastic longitudinal beam and the floating beam are respectively formed as plate-shaped beams, and the elastic beams are connected to the maximum plane of the floating beam.

Further, the elastic cross beam and the elastic longitudinal beam respectively comprise a big head end and a small head end, the big head end gradually reduces in the extending process of the small head end, the big head end is connected to the inner platform, and the small head end is connected to the floating beam.

Further, the spring beam is connected to the middle section of the floating beam, which includes a recess such that the height of the middle section is smaller than the height of both sides.

The invention can also adopt the following technical scheme: the invention relates to a robot, which comprises a working arm driven by an actuator to execute work, wherein the tail end of the working arm comprises a control module and a connector used for connecting various task tools, the multidimensional force sensor of any one of the previous items is arranged in the connector, the sensor is used for detecting first multidimensional force information and second multidimensional force information, and the control module judges that the robot normally operates compared with the prior art only when the first multidimensional force information and the second multidimensional force information are consistent, the beneficial effects of the specific embodiment of the invention are that: the elastic beam of the multidimensional force sensor comprises an elastic cross beam and an elastic longitudinal beam which are mutually perpendicular and crossed and are respectively connected with the inner platform and the outer frame, and the elastic beam has good continuity, good decoupling performance and good sensitivity. The redundant detection stress information of the two groups of strain gages can improve the working reliability of the multidimensional force sensor, and the fault information of the sensor can be easily found. Meanwhile, the structural design of the elastic beam and the floating beam is convenient for arranging a plurality of strain gauges meeting the requirement of double channels.

Drawings

The above-mentioned objects, technical solutions and advantages of the present invention can be achieved by the following drawings:

FIG. 1 is a schematic diagram of a multi-dimensional force sensor according to an embodiment of the invention

FIG. 2a is a top view of the multi-dimensional force sensor of the embodiment of FIG. 1

FIG. 2b is a cross-sectional view of FIG. 2a taken along section line A-A

FIG. 3 is a top view of the multi-dimensional force sensor of the embodiment of FIG. 1

FIG. 4 is a bottom view of the multi-dimensional force sensor of the embodiment of FIG. 1

FIG. 5 is a schematic view of a robot according to one embodiment of the invention

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, a clear and complete description of the solutions according to the embodiments of the present invention will be given below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention. It should be noted that the terms "upper", "lower", "left", "right" and the like are used herein for illustrative purposes only and are not limiting. The description of the orientations herein is with the multi-dimensional force sensor placed horizontally as a reference angle.

The present invention provides a multi-dimensional force sensor, referring to fig. 1-4, the multi-dimensional force sensor 1 includes an outer frame 10, an inner platform 20, and a plurality of elastic beams 30 radially distributed between the outer frame and the inner platform, wherein the elastic beams 30 include elastic cross beams 31 and elastic stringers 32 vertically crossing each other to form a cross-shaped cross section. The elastic cross beam 31 is arranged parallel to a horizontal plane, the elastic longitudinal beam 32 is arranged perpendicular to the horizontal plane, the elastic cross beam 31 divides the elastic longitudinal beam 32 into an upper part and a lower part in the vertical direction, and the upper part and the lower part are symmetrically arranged relative to the elastic cross beam 31; the elastic longitudinal beam 32 divides the elastic cross beam 31 into a left part and a right part in the horizontal direction, and the left part and the right part are symmetrically arranged relative to the elastic cross beam 31. Through setting up elastic cross beam 31 and the elastic longitudinal beam 32 of perpendicular alternately setting, make the both ends of elastic cross beam 31 and elastic longitudinal beam 32 connect outer frame 10 and interior platform 20 respectively simultaneously, elastic cross beam 31 and elastic longitudinal beam 32 set up in succession and connect interior platform 20 and outer frame 10, the centre does not have the blocking, elastic beam 30 does not have obvious abrupt change, stress concentration does not have, and fatigue resistance is good. Meanwhile, 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 comprises a neutral axis, the normal stress value on the neutral axis is 0, the elastic cross beam 31 and the elastic longitudinal beam 32 are arranged in a crossed mode and extend in the horizontal direction and the vertical direction respectively, and therefore the detection of the multidimensional force sensor 1 is far away from the neutral axis, and the detection sensitivity is good.

Preferably, the elastic cross beam 31 includes openings located at different sides of the elastic longitudinal beam 32, and further, the openings of the elastic cross beam 31 are symmetrical along the elastic longitudinal beam 32, and 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.

The elastic beam 30 of the multidimensional force sensor 1 is stuck with a strain gauge 40, the elastic beam is deformed when stressed, and the strain gauge detects stress information. The outer frame 10 includes a floating beam 12 and a supporting portion 11, the supporting portion 11 is connected to the adjacent floating beam 12, one end of the elastic beam 30 is connected to the floating beam 12, the other end is connected to the inner platform 20, the multi-dimensional force sensor 1 includes two sets of strain gauges to detect stress information of each dimension of the multi-dimensional force sensor 1, wherein the first set of strain gauges is distributed on the elastic beam 30, and the second set of strain gauges is distributed on the elastic beam 30 and/or the floating beam 12. Through setting up two sets of strain gages of redundancy, when the inaccurate circumstances of detection takes place for one of them strain gage, can in time be found, avoid adopting inaccurate sensor information, guaranteed the reliability that the sensor detected. Meanwhile, the structural design of the elastic beam is convenient for arranging more strain gages, so that when two groups of strain gages are adopted, the elastic beam can be provided with two groups of strain gages, and meanwhile, the strain gages can be distributed on the floating beam, so that the strain gages are concentrated on the position with better detection effect of the elastic beam and/or the floating beam as much as possible.

When the strain gauge is disposed on the elastic beam 30, the first set of strain gauges is preferentially disposed, and the sensitivity of detection on the side of the elastic beam close to the inner platform is better, so that at least most of the strain gauges 40 of the first set of strain gauges are disposed on the side of the elastic beam 30 close to the inner platform 20, so as to improve the sensitivity of detection of the sensor.

In a specific embodiment, the second set of strain gages is distributed on the elastic beam 30 or the elastic beam 30 and the floating beam 12, at least most of the strain gages 40 of the second set of strain gages are arranged at positions of two ends of the floating beam 12 close to the supporting portion 11 in real time, and because two ends of the floating beam 12 are easier to deform, the strain gages 40 are arranged at two ends of the floating beam, which is beneficial to improving the sensitivity of the sensor detection, meanwhile, when the information of the force detected by the multidimensional force sensor 1 is more, the first set of strain gages comprise more strain gages 40, the position with the best sensitivity of the elastic beam 30 is mainly used for distributing the first set of strain gages, and the second set of strain gages are mainly distributed at positions with better sensitivity of the floating beam 12, which is beneficial to improving the sensitivity of the multidimensional force sensor.

The elastic beam 30 of the multidimensional force sensor 1 comprises an elastic cross beam 31 and an elastic longitudinal beam 32, the elastic cross beam 31 is parallel to the horizontal plane, the elastic longitudinal beam 32 is perpendicular to the horizontal plane, the elastic cross beam 31 and the elastic longitudinal beam 32 are respectively plate-shaped beams, the elastic cross beam 31 and the elastic longitudinal beam 32 are mutually symmetrically arranged, and the multidimensional force sensor 1 is better in decoupling performance due to the symmetrical structure. 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, four elastic beams 30 constitute a cross beam, and an elastic cross beam 31 and an 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. Meanwhile, the sensor includes four floating beams 12, and four elastic beams 30 are connected to one floating beam 12 each, and adjacent floating beams 12 are connected by a support 11.

The support part 11 is used for connecting adjacent floating beams 12 to support the floating beams 12 on the outer ring of the sensor, and the sensor can further comprise a base 13, the support part 11 is connected to the base 13, the support part 12 extends along the vertical direction to set the base 13, the elastic beams 30 and the floating beams 12 on different planes, the base 13 is used for fixedly mounting the multi-dimensional force sensor 1, and in particular, the base 13 comprises radial holes so as to facilitate radial connection, such as connection to a robot joint.

In one embodiment of the present invention, the elastic cross beam 31, the elastic longitudinal beam 32 and the floating beam 12 are respectively formed as plate-shaped beams, the elastic beam 30 is connected to the maximum plane of the floating beam 12, the floating beam 12 is easy to deform, and the detection is relatively sensitive when the strain gauge 40 is arranged on the floating beam 12. Meanwhile, since the inner platform 20 and the outer frame 10 are mainly connected by the elastic beams 30, in order to solve the overload problem, it is preferable that an overload protection portion is disposed between the supporting portion 11 and the inner platform 20, so as to avoid damage caused by overload of the force sensor, and the specific structure of the overload protection portion is not the protection focus of the present invention, and is not repeated herein.

The elastic cross members 31 and the elastic stringers 32 are both plate-like beams, preferably comprising a large head end and a small head end, the plate-like beams tapering from the large head end to the small head end, the large head end being connected to the inner platform 20 and the small head end being connected to the floating beam 12. The plate-shaped beam is a trapezoid plate-shaped beam, namely, the side where the lower bottom surface of the trapezoid is located is a big head end, and the side where the upper bottom surface of the trapezoid is located is a small head end. The elastic beam 30 with the structure increases the strain of the multidimensional force sensor 1, has stable strain gradient, can increase the patch position of the strain gauge, and is convenient for patch. Specifically, the elastic cross member 31 and the elastic side member 32 may include plate-like beams having the same structure, or the elastic cross member 31 and the elastic side member 32 may include plate-like beams having different structures.

When the multi-dimensional force sensor 1 is attached with strain gauges, the strain gauges 40 may be disposed on the left and right surfaces of the elastic cross beam 31, and the strain gauges 40 may be disposed on the upper and lower surfaces of the elastic longitudinal beam 32, i.e., the strain gauges may be disposed on the upper, lower, left and right surfaces of the elastic longitudinal beam. Meanwhile, the strain gauge 40 of the floating beam 12 is arranged on the largest surface of the floating beam, so that the deformation condition of the floating beam 12 is sensitively detected, and the stress information of the sensor is further obtained. In a specific embodiment, the multi-dimensional force sensor 1 is a six-dimensional force sensor, the sensor comprises 48 strain gages, and the first set of strain gages and the second set of strain gages each comprise 24 strain gages forming 6 full bridge circuits for redundant detection of six-dimensional forces of the six-dimensional force sensor. In other embodiments, the multi-dimensional force sensor may be a three-dimensional sensor or the like with other dimensions by adjusting the number and mounting positions of the strain gages.

The elastic beam 30 is connected to the floating beam 12, and the sensitivity of the detection is improved as the height of the elastic longitudinal beam 32 becomes larger within a certain range. The height of the spring beam 30 is less than the height of the floating beam 12. The spring beam 30 is connected to the middle section of the floating beam 12, and the middle section of the floating beam 12 includes a recess so that the height of the middle section is smaller than the heights of both sides, thereby facilitating the processing of the multi-dimensional force sensor.

The beneficial effects of the above preferred embodiment are: through the design of the elastic beam of the multidimensional force sensor, the elastic beam is convenient for arranging more strain gauges, and meanwhile, the elastic beam has good continuity, symmetrical structure, easy processing, good decoupling performance and better sensitivity. The multi-dimensional force sensor comprises two groups of stress information of the strain gauge redundant detection sensors, so that the detection reliability of the sensors can be improved, and the multi-dimensional force sensor has great significance for scenes with high precision requirements.

The present invention is also used to provide a robot, referring to fig. 5, the robot 6 includes a working arm 60 driven by an actuator to perform a task, the end of the working arm 60 includes a control module and a connector 70 for connecting various task tools, the multi-dimensional force sensor described in any one of the foregoing is disposed in the connector 70 to detect the stress of the end of the robot, the sensor is used to detect first multi-dimensional force information and second multi-dimensional force information, the first multi-dimensional force information and the second multi-dimensional force information are based on redundant detection of the same detection object, and the control module determines that the robot is operating normally only when the first multi-dimensional force information and the second multi-dimensional force information are consistent. Specifically, when the first multidimensional force information and the second multidimensional force information are detected to be inconsistent, the control module can control to generate an alarm instruction and the like so as to remind a user of abnormal conditions of the multidimensional force sensor, the situation that the robot cannot identify the abnormal conditions is avoided, reliability of multidimensional force information detection is ensured, and reliable operation of the robot is ensured. Specifically, the robot is a collaborative robot capable of performing specific tasks according to user teachings. In a specific embodiment, the multi-dimensional force sensor is a six-dimensional force sensor, referring to fig. 1-5, the multi-dimensional force sensor 1 includes 48 strain gages 40, the first set of strain gages and the second set of strain gages each include 24 strain gages to form 6 full bridge circuits, each full bridge circuit is used for detecting one-dimensional force information, and the six full bridge circuits can detect the six-dimensional force information, and meanwhile, the first set of strain gages and the second set of strain gages respectively detect the six-dimensional force information, that is, redundant detection of the six-dimensional force information is achieved, for example, the first set of strain gages can be distributed on an elastic beam, and the second set of strain gages can be distributed on a floating beam, so that the first set of strain gages and the second set of strain gages are respectively distributed at positions better than the elastic beam and the floating Liang Lingmin degrees.

The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. The double-channel multidimensional force sensor is characterized by comprising an outer frame, an inner platform and a plurality of elastic beams which are radially distributed between the outer frame and the inner platform, wherein the elastic beams comprise elastic cross beams and elastic longitudinal beams which are vertically and crosswise arranged to form a cross-shaped section; the outer frame comprises floating beams and supporting parts connected with adjacent floating beams, one ends of the elastic cross beams and the elastic longitudinal beams are connected with the floating beams, and the other ends of the elastic cross beams and the elastic longitudinal beams are connected with the inner platform; the sensor comprises two groups of strain gages for redundant detection of stress information of each dimension of the multi-dimensional force sensor, wherein the first group of strain gages are distributed on an elastic beam, the second group of strain gages are distributed on a floating beam or on the elastic beam and the floating beam, at least most of strain gages of the second group of strain gages are arranged at positions, close to a supporting part, of two ends of the floating beam, the first group of strain gages and the second group of strain gages respectively comprise 24 strain gages to form 6 full-bridge circuits for redundant detection of six-dimensional stress of the six-dimensional force sensor, and the multi-dimensional force sensor is the six-dimensional force sensor.

2. The multi-dimensional force sensor of claim 1, wherein at least a majority of the strain gages of the first set of strain gages are disposed on a side of the spring beam proximate the inner platform to increase the sensitivity of the sensor detection.

3. The multi-dimensional force sensor of claim 1, wherein the sensor comprises four spring beams forming a cross beam, the sensor comprising four floating beams, one connected to each of the four spring beams.

4. The multi-dimensional force sensor of claim 1, wherein the elastic cross beams, elastic side beams, and floating beams are each formed as plate-like beams, the elastic beams being connected to a maximum plane of the floating beams.

5. The multi-dimensional force sensor of claim 4, wherein the elastic cross beams and the elastic stringers comprise a large head end and a small head end, respectively, the large head end tapering during extension to the small head end, the large head end being connected to an internal platform, the small head end being connected to a floating beam.

6. The multi-dimensional force sensor of claim 1, wherein the spring beam is connected to a middle section of the floating beam, the middle section of the floating beam including a recess such that the height of the middle section is less than the height of both sides.

7. A robot comprising a working arm driven by an actuator to perform work, wherein the tail end of the working arm comprises a control module and a connector for connecting various task tools, the multi-dimensional force sensor as set forth in any one of claims 1-6 is arranged in the connector, the sensor is used for detecting first multi-dimensional force information and second multi-dimensional force information, and the control module judges that the robot is normally operated only when the first multi-dimensional force information and the second multi-dimensional force information are consistent.