3-DOF Distributed Flexibility Plane Compliant Mechanism Research On Motion Characteristics And Control

Precision positioning technology is widely used in nano-technology,bio-engineering,optical component positioning and other technical research in the field of basic key technologies which is playing an important role in these areas.Precision positioning platform is to ensure the precise positioning of the key technical support.Nowadays,with the rapid development of science and technology,precision positioning technology applications have been further expanded,which makes precision positioning platform positioning accuracy requirements are getting higher and higher.Therefore,the study of high-precision precision positioning platform has a very important theoretical value and practical significance.Based on the theory of flexible parallel mechanism,this paper analyzes the comprehensive performance of the distributed flexibility plane compliant mechanism combined with the topology theory,and designs the controller to track the dynamic platform of the flexible plane Track accuracy control.The details are as follows:(1)A three-degree-of-freedom distributed flexibility plane compliant mechanism is proposed.The characteristics of the flexible parallel mechanism and the distributed flexibility plane compliant mechanism are introduced respectively,and analyze the kinematics of this mechanism with closed-loop vector method.By using the obtained kinematics equation,the working space of the mechanism is solved,and obtaining the set of the end of the actuator,which is the required work space.The motion characteristics of the mechanism are simulated by three-dimensional analysis software.The results demonstrate the validity of the selected kinematics model.(2)Using the Lagrangian method to solve the dynamic equation of the distributed flexibility plane compliant mechanism,because this method is generally applied to the solution of the flexible parallel mechanism dynamics equation.The modal analysis of the mechanism is carried out by means of three-dimensional analysis software,and the natural frequency and mode of the first-order mode of the mechanism are obtained.The results show that it is effective in the establishment of the dynamic model of the distributed flexibility plane compliant mechanism.(3)Based on the input-output Jacobian matrix of the distributed flexibility compliant planar compliant mechanism,and designing the auto-disturbance-rejection controller.Through the design of the dilution state observer,the dynamic coupling of the distributed flexibility plane compliant mechanism and the total disturbance as the external disturbance are compensated,and comparing with the mechanism under the PID control.To realizes the high precision control of the distributed flexibility plane compliant mechanism.The simulation results show that the auto-disturbance rejection control is superior to the traditional PID control,satisfying the performance requirements of the system and proving the feasibility of the designed controller.(4)For the design of the three-degree-of-freedom distributed flexibility plane compliant mechanism for machining and experimenting.The trajectory tracking displacement curve of the mechanism are obtained,and it is proved that the distributed softness of the plane can be sub-micron.