Adaptive robust control of linear electrical loading system with dynamic friction compensation

Linear electrical loading system (LELS) driven by electrical cylinder with permanent magnet synchronous motor (PMSM) offers several advantages of high transmission efficiency and high precision positioning, however these advantages are obtained at the expense of larger friction in mechanism and added difficulties in controlling such a force servo system. To address the problems, the LuGre friction model is modified with a smooth transition function between low speed and high speed to make the internal state steady, then the modified LuGre model is applied for dynamic friction compensation. Then a discontinuous-projection-based desired compensation adaptive robust controller (ARC) is constructed, which makes full use of the LuGre friction model in the presence of dynamic friction effects. Comparative simulation results are conducted on a LELS simulation system. The simulation results illustrate the effectiveness of the proposed scheme.