Adaptive prescribed performance output feedback control for full-state-constrained DC motors subject to uncertainties and input saturation

An adaptive output feedback controller with prescribed performance is performed for full-state-constrained DC motors with uncertainties (including parametric uncertainties and disturbances). A distinguishing feature is that when only partial states are measurable, not only parametric uncertainties and disturbances are addressed but also the quantitative analysis of control error and state constraints is realized. For this purpose, an extended-state observer is constructed to estimate disturbances and unmeasurable states, while adaptive control is employed to approximate unknown parameters. A new prescribed performance-barrier Lyapunov function is established to maintain the control error and all system states within specified boundaries. Then, taking saturation compensation into account, the proposed control algorithm is designed through the backstepping technique to ensure that all signals in the closed-loop system are bounded. Finally, several experimental results demonstrate the effectiveness of the proposed algorithm.