Adaptive robust control of the surface mounting equipment based on dynamic LuGre model

摘要

The surface mounting equipment (SME) is critical and complex in electronic assembly process. The key issue of SME is to realize accurate positioning and high-speed under the influence of parametric uncertainties (e.g., unknown gravitational load) and uncertain nonlinearities (e.g., friction). For achieving this aim, the adaptive robust control (ARC) based on dynamic LuGre model algorithm is proposed. This algorithm uses a discontinuous projection-type online parameter adaptation method for unknown parameters estimation. Compared with the traditional static friction compensation method, dynamic LuGre model is introduced. In order to estimate unmeasurable friction state, the nonlinear state observer is designed. Under the assumption that the disturbance is bounded, the system can achieve exponential stability. The backstepping technique with Lyapunov function is employed to construct the controller. Then, the controller is implemented on the SME system, along with PID and adaptive control scheme. Experimental results indicates the improved of tracking accuracy and the effectiveness of its application in the SME system.