ABSTRACT
As is well known, disturbances exist in most practical controlled processes, due to friction and load variations in mechanical and electrical systems, measurement noise, environmental disturbance, errors caused by sensors and actuators, and so on. Hence, to guarantee stability and improve performance, how to attenuate, compensate and reject the disturbances, especially for the nonlinear systems, becomes a crucial problem [30, 36, 106, 113, 159, 182, 221]. When a system encounters multiple disturbances, hierarchical/composite control strategies consisting of DOBC and another control scheme, such as robust control [202], sliding mode control [203, 201], adaptive control [93] and so on, are presented to achieve anti-disturbance performance.
