Research On Position-posture Measurement And Control System For 3-PSP Parallel Manipulator

Based on 3-PSP parallel manipulator, the paper presents the parallel manipulator system with position-posture measurement and control. Meanwhile, the system is studied by theoretical analysis, numerical simulation and experimental verification methods.The paper analyzes the kinematics of the 3-PSP parallel manipulator, builds its kinematics equations using the Euler transformation and deduces the analytical expression of the forward kinematics solution for the first time. Under circumscribed space, it identifies the characteristic boundary and the change regulation of the position-posture space and obtains the corresponding relations of the structural parameters and the position-posture space for the purpose of the largest volume of position-posture space. In the condition of single-variable control, the law of motion is discussed with numerical simulation.The position-posture measurement system adopts high accuracy laser displacement sensor. As the existing problem that the value of the sensor is unstable under measuring multilayer dielectric, the fitting algorithm based on waveform characteristics and the peak recognition algorithm based on correlation are proposed. The 3-DOF position-posture measurement system is designed and its mathematical models and calibration approaches are discussed in detail.The paper designs the closed-loop control system of parallel manipulator, establishes its mathematical models, provides closed-loop control model and expounds the effect relationship of the structure errors and position-posture errors of the closed-loop control system. In order to improve the accuracy, parameter calibration algorithm based on artificial bee colony algorithm is implemented to calibrate the angles on the move platform.The paper introduces the design of hardware and software of the system. The experiment results corresponds to the static regulation and dynamic reaction indicate that the accuracy of rotation is no more than 0.0001 rad and the accuracy of translation is in the range of ±0.002 mm while static regulation and the accuracy of translation is ±0.002 mm while dynamic reaction. Finally, the 3-PSP parallel manipulator can reach the precision with micrometer-level.