A stable scheme for automatic control reconfiguration in the presence of actuator failures

The paper describes the design of an automatic control reconfiguration scheme for accommodation of actuator failures in a class of plants where the number of control inputs is larger than the number of controlled outputs. One of the main features of the proposed scheme is that the control reconfiguration is achieved automatically based only on the response of the overall system. The method is developed for the case when one or more actuators freeze in a certain position and do not respond to subsequent commands. We assumed that the information about the failure is not available to the controller. To solve this problem, a control law with adjustable parameters is introduced, and, using a convenient parametrization of the overall system, the resulting error model is expressed in a somewhat modified form as compared to those arising in standard adaptive control. The design of the corresponding adaptive laws based on Lyapunov analysis allow us to prove global stability of the overall scheme in the presence of multiple actuator failures