The Research On Adaptive Method Of Force And Position Control For Industrial Robot

With the rapid progress of modern science and technology,the industrial robot is developing towards the direction of high intelligence and has been playing an important role in the field of multiple domains.Force control and trajectory tracking capability of industrial robot are its main core,most applications require that robot can force control or trajectory tracking at least.The model of the industrial robot has the character of nonlinear and strong couple,which makes the controller design for the industrial robot become more difficult.In order to make the industrial robot better serve for social production,the research topic of this paper are force control and trajectory tracking.The main research work of this paper is illustrated as follows:(1)The impedance control principle and realization method are studied in this paper,and impedance control method based on position is proposed to control the interaction between robot and environment.The dynamic equation of force error of this method is analyzed and the influence of environmental parameters on force control accuracy is known.Through simulation study we summarize that how impedance parameters influence static force control dynamic force control when environmental parameters is unchanged.It lays a theoretical foundation for the design of adaptive impedance control strategy.(2)In order to overcome workpiece parameter uncertainty,we apply the model reference adaptive control(MRAC)to the force error dynamic equation of impedance control,and then design a adaptive impedance controller that satisfy asymptotically stable through lyapunov stability design method.This method can indirectly adjust impedance parameters to improve system's environmental adaptability and robustness.By comparing the simulation results,it proves that the designed adaptive impedance controller has better control performance than the pure position type impedance controller.(3)It is difficult to quantitatively determine the dynamic and steady-state performance of the tracking error for the traditional robot adaptive control method,and can not realize the global problem of tracking initial value,thus a motion control strategy with adaptive guaranteed performance(PPB)is proposed.As a result,for any given initial states,the tracking error will converge into a preset set at a conservatively well-defined speed within a pre-specified time,and then further deduce into a smaller and preassigned residual set.All internal signals in the closed-loop are ensured to be globally ultimately uniformly bouned through through lyapunov stability certificate.Finally,the effectiveness of this method is verified by simulation experiments.Meanwhile,the algorithm can also be applied to impedance force control and obtain good results.