Research Of The Traction Six-axis Force Sensor For Human-Robot Collaboration

As the level of intelligentization of industrial robots continues to increase,human-machine collaboration based on force sensing has also become a research hotspot.Among them,robotic traction teaching for human-machine cooperation,due to its interactive and friendly features,has revolutionary significance for the development of robot teaching technology in the future.However,if there is a load at the end of the robot during the traction teaching,the decoupling measurement of the teaching traction force and the robot end contact force cannot be directly performed at this time,so the robot traction teaching is not widely used in the industry.In order to solve this problem,this paper designs a traction six-dimensional force sensor.The six-dimensional force sensor can structurally decouple the teaching traction and the robot end contact force when the traction type is directly taught.In this way,when the robot has a workload,direct teaching of the human hand traction can also be realized.The main design and research work of the traction six-dimensional force sensor is as follows:(1)Designed the traction sensor system for industrial robots,including industrial robot platform,six-dimensional force elastic body,strain gauge bridge circuit,data acquisition card hardware,data acquisition software and data processing algorithm.It also introduces the division of labor and role of each component of the sensor system.(2)According to the advantages and disadvantages of different sensor elastomer structures and the characteristics of human-handed six-dimensional force,an integrated full-cut six-dimensional thin-wall cylinder sensor is designed as the structure of the traction six-dimensional force sensor.Further,important dimensional parameters of the integral thin-walled cylindrical six-dimensional elastic body are assumed.The mechanical stress analysis of the elastomer structure was carried out under the action of six-dimensional force.The critical dimension parameters of the elastomer are obtained by using the sensitivity requirements of the elastomer and the allowable stress as the boundary conditions.The innovative design idea greatly reduces the pre-size design problem of the sensor,and proposes an effective method and criterion for the design of the thin-walled cylinder elastomer.(3)The finite element model of the elastic sensitive body is established.According to the stress and strain of the finite element model of elastic sensitive body under six-dimensional force,the main static characteristics of the sensor(sensitivity,inter-dimensional coupling and linearity)are analyzed.The sensitivity of the elastic sensitive body is high and the linearity is good,but there is a large inter-dimensional coupling..It provides a basis for subsequent patch and bridge circuit design.(4)The strain gauge group and its patch orientation for measuring the six-way signal are designed to ensure that the strain gauge group has the highest sensitivity to the measured force or moment.The bridge circuit of the six-way signal strain gauge group is designed to ensure that the coupling effect of other five-dimensional force or torque generation on the measured local-dimensional signal is zero.(5)The sensor calibration experiment was designed,and the actual static characteristics of the sensor were analyzed to meet the design requirements.Finally,the decoupling matrix is calculated by measuring multiple sets of data according to the least squares method,and the decoupling of the six-dimensional sensor is realized.