Kinematic Design And Calibration Simulation Of An Orthogonal Delta Parallel Robot

This thesis focuses on the kinematic design and kinematic calibration of an orthogonal deltaparallel robot that has three translation degrees of freedom based on the kinematic analysis. Themain work listed as follows:According to the geometry of the orthogonal delta parallel robot，mobility analysis of themechanism is performed．Then the configuration parameters are defined, forward andinverse position relations are established．Based on the closed-loop vector chain，themapping of velocity from three actuated prismatic joints to the output of moving platform,namely, speed Jacobian matrix，is obtained by taking a derivative with respect to time．The configuration parameters are defined, which make the kinematic analysis and designpossible. The parameter-finiteness normalization method is employed to quantify theparameters of the robot, and then the optimization design space of the orthogonal deltaparallel robot is defined. The mapping models of error, speed, and load from drive joints tomoving platform are formulated and all the indexes concerning condition, speed,load-bearing capability are defined. The global performance indexes are proposed. Therelationship between global performance indexes and the configuration parameters is studiedin the optimization design space, and the figures of global performances are obtained.Optimal design of the robot is implemented according to the figures of global performances.The kinematic calibration is studied based on the kinematic analysis of the orthogonal deltaparallel robot. According to the structural characteristics of the robot, a simplifiedmechanism model is obtained.24geometric error sources which affect the location accuracyare analyzed and studied. A linear error model is directly established using vectorperturbation method and the parameter identification model is further established by theleast squares method. Two strategies for error compensation are developed by modifying theideal input and the ideal parameters of the system. Similarly, the computer simulation of thecalibration is carried out successfully using MATLAB.A new, simple and effective non-parametric calibration method is used. This simple andstraightforward way of compensation uses the locally linear behavior of the kinematic model.A piecewise multi-linear interpolation is used for the transformation of the configurationspace. The calibration method is verified using computer-aided simulation in the case oforthogonal delta parallel robot.