Study Of Friction Compensation Based On Nominal Characteristic Trajectory Following Method

There are frictions in mechatronic servo systems inevitably, which degrade the systems' control performance greatly. Based on nominal characteristics trajectory following method, the friction compensation for the mechatronic servo systems is studied.The nonlinear friction models and friction compensation are presented based on the introduction of the friction's complexion. The friction models consist of static friction models and dynamic friction models. The friction compensation metheds based on friction models and not based on friction models are presented too.The theory of the nominal characteristics trajectory following method which is not based on friction models is studied as first step. The detailed design steps of the controller is presented too. The platform of the inverted pendulum sliding real time motion control system is construction in MATLAB7.0/xPC target environment. The hardware and the software of the platform are presented.The speed signal is disturbed heavily. The frequency spectrum analysis of the speed signal is carried out and the corresponding digital low-pass filters are designed for the subsequent experiments' favourable running. The nominal characteristics trajectory following controller which is under normal running condition is constructed after the real time open-loop identification.The digital PD controller is constructed under normal running condition, the running performance of the two controllers is compared under many different running conditions. Experiments not only demonstrate that the nominal characteristics trajectory following controller's control performance is better than the digital PD controller's, but also demonstrate that the nominal characteristics trajectory following controller has great rejection to friction for its high positioning accuracy.