Design And Control Of A Spherical Motor For Conformal Printing Of Curved Surface

Multi-DOF platform has been applied in various fields,such as radar base,AR device and CNC milling machine.Traditional multi-DOF platform is constituted by moving platform and rotary motor.Several 1-DOF rotary motors are connected to realize the rotation in multi-DOF which is complicated and bulky.Besides Singularity problem may appear in its moving range.In the process of conformal printing,substrate is fixed on multi-DOF platform in order to realize the circuit printing process which is required to be continuous and is sensitive to velocity change.Spherical motor has a swift response and nonsingular moving range which is suitable for this application.This paper designs a spherical motor as the alternative of traditional rotary motor in the multi-DOF system of conformal printing platform,which is one part in Flexible Curved Electronic Conformal Manufacturing Integrated Platform,to provide better printing performance.the spherical motor which provides 3-DOF in rotation together with the displacement stage construct a 6-DOF system.This paper illustrates the design processes of spherical motor which include the mechanical design,dynamic model deduction and electromagnet torque model formulation.two methods are presented in order to solve the inverse solution question of 6-axis system's kinematic model.Besides,sliding mode control system is developed to deal with the model uncertainty and nonlinear problem in spherical motor.The feasibility of applying spherical motor in conformal printing and the result of sliding mode control has been verified by simulation.The accuracy of spherical motor models and the control performance of sliding mode control has been tested by experiment and the average error is 0.056°.