Development and Calibration of a Hyperstatic Six-component Force/Torque Sensor

The six-component force/torque sensor has become one kind of the most important sensors with the ability of measuring all the external forces and torques. A novel hyperstatic six-component force/torque sensor based on the Stewart platform structure,which can be used for the force measurement of the robot wrist,is proposed,and its structural optimal design,finite element analysis and calibration experimentation is presented. The characteristic of the sensor structure is analyzed in comparison with the traditional Stewart platform-based sensor. The mathematical expression of the sensor's force mapping matrix is introduced. The condition number and generalized amplifying coefficient defined by singular values of force Jacobian matrix are used to evaluate the performances of isotropy and sensitivity of the sensor respectively. The optimal design of the sensor structure is performed with the objective of achieving high measurement sensitivity and good isotropy. The sensor prototype is fabricated,and the static and dynamic characteristics of the sensor are analyzed with finite element analysis software package ANSYS. The calibration device is manufactured,and the data acquisition and processing system is developed. The theoretical and experimental study of the static calibration of the sensor prototype is carried out. The results of simulation analysis and calibration experimentation prove the feasibility of the hyperstatic sensor structure,and the contents of this paper possess theoretical significance and engineering value for the further research and practical application of the six-component force sensor.