Observer-based receding horizon controller for position and force control of a pneumatic actuator

Abstract

Pneumatic systems are widely used in automation industries and in the field of automatic control. Unfortunately, some nonlinearities are existed in these actuators. These nonlinearities have made controlling these actuators more difficult to get good dynamic performance. In this project, Receding horizon controller (RHC) is proposed to control the position and the force of a pneumatic actuator. RHC is a predictive controller that predicts the future output and decides the acting signal to reduce the future errors. The type of RHC used in this project is a state feedback controller. Three types of pole assignment observers are used in this project in order to estimate the states of the position and the force models. The observers are designed, incorporated with RHC and then compared in terms of their estimation errors. The implementations of RHC and the observers are carried out using MATLAB/Simulink. Using a data acquisition system (DAQ) real time control between the computer and the pneumatic actuator is established. The RHC shows good control performance both in controlling the position and the force. The experimental and the simulation results of RHC are compared to validate the controller. To further evaluate the RHC controller, its results are compared with other controllers done in previous works, and it is found that RHC has some advantages over these controllers in terms of the control performance criteria.