Design And Experimental Research Of Rigid-Flexible Hybrid Parallel Three-Dimensional Force Sensor With Large Deformability

Multi-dimensional force sensor possesses the advantage to measure multiple components of force and moment.Thus,it is widely used in different applications such as aerospace,mechanical processing,biomedical science,automatic assembly,etc.In recent years,with the rapid development of artificial intelligence and robotics,the demand for multi-dimensional force sensor with flexibility and deformability is increasing dramatically in the fields of human-robot interaction and medical rehabilitaition.In this paper,theoretical analysis and experimental research on a rigid-flexible hybrid parallel three-dimensional force sensor with large deformability are carried out.The main research contents of this paper are as follows:Firstly,the concept of rigid-flexible hybrid is introduced into multi-dimensional force sensing technology,and a translational parallel mechanism with constant force transfer relationship is introduced into the structure design of force-sensing element.Then a novel rigid-flexible hybrid parallel three-dimensional force sensor with large deformability is proposed.Based on the vector method,the mapping of the applied external load and the reacting forces of measuring branches of the sensor is derived.The deformable principle of the sensor is revealed.Based on the established measurement model of traditional parallel multi-dimensional force sensor,the characteristics of the proposed sensor are compared and analyzed.Secondly,combined with the static performance indexes of multi-dimensional force sensor,the isotropic performance of the rigid-flexible hybrid parallel three-dimensional force sensor with large deformability is studied by using mathematical analytic approach.Based on the constrained equation of the sensor's deformable range,the corresponding optimization objective function is established,and the influence of the main structural parameters on the deformable range of the sensor is analyzed.The reconfigurable principle of measurement range is described,and the relationship between the measurement range of the sensor and main structural parameters is studied.Then,based on the above optimization results,a rigid-flexible hybrid parallel three-dimensional force sensor with large deformability is designed in detail.The critical components of the sensor are manufactured by using 3D-printing technology.Finally,a prototype of the sensor is developed,and the modal analysis is also carried out.Based on that,a loading calibration experiment system is built.Finally,calibration experiment is performed based on the developed sensor prototype.The calibration matrix and error matrix of the sensor were obtained,and the main performance indicators of the sensor were analyzed.The eccentric loading experiment was carried out on the sensor,and the influence of the moment on the measurement accuracy of the sensor is studied.On this basis,the error sources of the sensor are analyzed.