Model Reference Adaptive Control for Steering Application of Agriculture Machines

Modern agricultural machines happens to work for prolonged periods of time in a considerably harsh environments. This puts a higher demand on the automatic control systems and steering control in particular. Long-term machine operation leads to variance of the physical parameters of the working fluid, positive overlap in proportional valve, working temperature and machine components. This problem can be addressed by introduction of adaptive controllers. The present research is focused on the design and application of model reference adaptive controller (MRAC) for control of steering angle of a heavy duty agriculture mobile machine through a hydraulic cylinder. The synthesized controller is based on simple integrator model of the steering cylinder and Lyapunov stability theorems. The closed-loop system achieves good performance and the adaptive gain is stabilized around its mean value too.