Controller Design And Parameters Tuning Based On The Dynamic Identification Of A Serial Robot

Nowadays,the industrial fields have been constantly calling for even higher automatic efficiency—On the one hand,the increase of running speed and positioning accuracy of traditional industrial robots is one of the solutions,on the other hand,the expansion of robot to such interaction manipulation applications as part assembly,human-robot collaboration is another.In view of the former,firstly,it is of crucial significance that the most precise dynamic parameters describing the robot model should be identified and then considered,for vibrations,frictions,inertial forces,among other things,induced by the robot dynamics would otherwise make it difficult to be realized.Secondly,based on the precise identified parameters,it is then possible for the model-based controllers,which take into account of state feedback compensation,to be designed.While for the latter,it is required that the interaction control strategies based on the identified parameters be studied and applied.As for the first issue—dynamic identification of robot,this paper takes KUKA LBR iiwa 14 R820 as the object of study.Then firstly,the kinematics and dynamics models of it are derived from the given corresponding theories.Secondly,the basic procedures of parameter identification is outlined,where heavy emphases are put on parameter identification algorithm and acquisition of optimal excitation trajectory.Thirdly,the dynamic parameters of iiwa are identified through the procedures including experimental data acquisition,data processing and calculation of dynamic parameters using identification algorithm.Finally,the precision and credibility of the parameters are validated by conducting both direct and indirect validation experiments.As for the second issue—study of interaction control strategies,this paper mainly focuses on impedance control strategy which is adopted by and integrated into the controller of iiwa.Since there is difficulty when choosing the suitable parameters of impedance controller in the face of various different interaction manipulation scenarios,and that's because there is a tradeoff between the high trajectory tracking precision and the small joint torque abrupt change,this paper first analyzes and then builds up the impedance controller based on the above identified parameters,therefore,a parameter tuning platform is set up in this paper,which facilitates the faster and more convenient determination of suitable impedance controller parameters.It can be seen in this paper that,validated by experiments,the identified parameters are of very high precision,and the comparisons between parameter tuning results of impedance controller show expected results,so the impedance controller built based on the identified dynamic parameters can be employed for the parameter tuning when using the impedance controller for interaction manipulation such as assembly.