Actuator Position Saturation Research Articles

Semi‐global consensus with position limited and rate disturbances via low gain feedback and integral sliding mode control

In this study, the authors investigate the semi-global leader-following consensus problem of multi-agent systems in the presence of both position saturation and bounded rate disturbances. Each follower agent is described by a general linear dynamic with actuator position saturation and rate disturbances. Based on low-gain feedback design technique and integral sliding mode, discontinuous and continuous control protocols are developed. It is established that semi-global leader-following consensus can be achieved under the assumptions that the system is asymptotically null controllable with bounded controls and the leader agent has a directed path to every follower agent. Simulations are presented to illustrate the results.

Stable adaptation in the presence of input constraints

For a class of linear dynamical systems with unknown parameters a direct model reference adaptive control framework is developed that provides stable adaptation in the presence of input constraints. The proposed design methodology, termed “positive μ -modification”, has the ability to protect the control law from actuator position saturation. The reference system is adaptively modified to ensure global asymptotic tracking for open-loop stable systems. For unstable systems an estimate for the domain of attraction is derived based on the input saturation magnitude and system parameters. Simulation of a benchmark example verifies the theoretical statements.