Matched Feedforward/Model Reference Control of a High Precision Robot With Dead-Zone

A matched feedforward/model reference control is proposed in this brief to improve the transient characteristics of systems with uncertain parasitic nonlinearities. In particular, attention is focused on a New England Affiliated Technologies (NEAT) four-axis positioning system which is designed for high-precision applications. Due to the presence of a dead-zone with variable boundaries in this robot, most conventional methods tend to produce unacceptable transients or steady-state errors. The proposed control method is analyzed for its properties and subsequently implemented on the NEAT robot for experimental verifications. It is observed that the matched feedforward/model reference control method is effective while robust to plant and dead-zone boundary uncertainties.