Design And Static Calibration Of Six-dimensional Force Sensor With Parallel Structure

Six-dimensional force sensor is a force sensor which can measure three-dimensional force and torque.Through continuous exploration,researchers have developed a six-dimensional force sensor with parallel structure,which can directly transform the measuring force of six connecting rod and the six-dimensional force on the platform under test.Due to its advantages such as large structural stiffness,small coupling effect and good measuring effect,it has been well applied in industrial robots,medical treatment and other fields.In this paper,a six-dimensional force sensor with parallel structure is designed according to the actual work needs,and some key problems in the structural layout and overall design of the sensor are analyzed.The specific contents of the paper are as follows:The isotropic evaluation index is the evaluation standard of the structure design and performance of the six-dimensional force sensor,and the detailed analysis and comparison of the used isotropic evaluation indexes are made,which provides the theoretical basis for the optimization design and the evaluation of the characteristics of the six-dimensional force sensor structure of the parallel structure.Six dimensional force sensor structure of parallel structure model,makes a preliminary analysis based on screw theory to build the space model of parallel mechanism,the action of external force analysis platform,the relationship between force and connecting rod bearing mechanics,structural parametric model is established,and the force of the structure and the mechanics of connecting rod bearing deduction,be based on the basic structural parameters of the force expression of jacobian matrix condition number.The overall design of the sensor is carried out,and the structural parameters under the conditions of decoupling constraint and isotropy of force and torque are analyzed.The structural parameters based on the optimal value of the matrix condition number are analyzed by numerical method,and the parameter range under the optimal structure is obtained.In this paper,the key problems of measuring thin section thickness of support rod,flexure hinge flexibility and SMT bridge design are analyzed,and the sensor model design is completed.The static calibration test analysis of the parallel structure six-dimensional force sensor prototype is carried out.The calibration device is designed according to the calibration principle of six-dimensional force sensor.The calibration is carried out by means of weight loading step by step,six measuring branches are calibrated and checked,six dimensional force and torque are statically calibrated for the six-dimensional force sensor,and the calibration matrix and error matrix of the designed six-dimensional force are obtained through the analysis of the calibration data.