Comparison of linear and nonlinear control of a slewing beam

The performance of two position control systems was studied. Proportional p lus derivative (PD) feedback control was considered along with PD plus posi tion times velocity feedback. An analytical model of the plant (a single li nk, very flexible manipulator) was identified, and computer simulations usi ng the two controllers were performed. The results clearly showed a decreas e in control effort for the system using nonlinear control when compared to a similar response for the system using PD control. Experimental results o n a slewing beam system verified this result. The system using the proposed nonlinear feedback control required significantly less energy to complete the same maneuver as the system using the standard PD feedback control. Oth er measures of performance (e.g., rise time, settling time, overshoot) show ed marginal improvement when the nonlinear feedback was added to the contro ller The principal issue here is the control effort required by the linear versus nonlinear controller to obtain the same, or similar, response to a c ommand.