Research On A Six-axis Heavy Force Sensor And Its Calibration System

Huge manufacturing equipments, such as large metal processing machinery and heavy equipment operators, play an important role in large complex parts manufacturing in harsh environment. But heavy equipment operators with multi degrees of freedom still need to be strengthened in our country. Heavy equipment operators, which are characterized by large inertia, multi degrees of freedom and heavy loads, require that its terminus executive arms be compliance with force and displacement. Hence, researches on developing heavy force sensors that can provide real-time feedback of six-dimensional forces is of vital importance.Multi dimensions and magnitude of force is a contradiction in multi axis heavy force measuring. To solve the contradiction, a measurement method is proposed and a sensor is designed based on principle of load-sharing with a six-axis heavy force measurement sensor. Effort is made to find the rule of the isotropy and the sensitivity performance indices which change with parameters of the structure. And a six-axis heavy force sensor with a max measurement range of 200KN is design and manufactured based on Stewart structure.To solve the similar problem between multi axis and magnitude of force in sensor calibrating, a six-axis heavy force calibration equipment with single force source is designed. The calibration equipment has a structure of 3 girders and 4 pillars, which is driven by motors, firstly decelerated by a synchronous belt, and then by gear change mechanism. The active girder moves with a lead screw which is driven by output motion of the gear change mechanism. By choosing the corresponding output equipment, the six-axis heavy force measurement sensor is calibrated by comparing with the standard force sensor on the active girder. The capability of the calibration machine is verified by finite element analysis model, and a calibration system which has a max measurement range of 200KN and a motion range of 700×800×1000mm.The sensor is calibrated by changing the position and direction of the 200KN steward six-axis heavy force sensor on the single source force calibration machine. Results show that the repeatability errors of the sensor is not more than 1%, the non-linearity error is not more than 1.2%, and the interference error in each direction is not more than 5%. It proves that the sensor designed is fine in performance, and can provide an important theoretical base for usage of the six-axis heavy force measurement sensor in heavy equipments.