Saturated output feedback control of uncertain helicopter dynamics and saturation compensator

Practically the control of actuators is limited and saturations can occur, so we are interested to investigate the control of the unmanned helicopter dynamics with bounded control inputs, actuator saturation compensation scheme and a nonlinear saturated observer for estimate the velocities without measuring them. The altitude and yaw angle tracking with saturated torque inputs is considered for an unmanned model helicopter dynamic with the nonlinearities such as high model uncertainties and dynamic coupling. A saturated adaptive output feedback tracking observer controller has been employed to deal with the uncertainties and the saturation compensation designing without velocity measurements.The closed -loop system performance and Semi-Global Uniform Ultimate Boundedness (SGUUB) of tracking errors are guaranteed based on the Lyapunov stability synthesis. The designed adaptive Multi-Layer Neural Network controller ensures that the altitude and the yaw angle track the reference signals under the input saturations. This paper also considering (1) the saturation problem of actuators, (2) Limit the error signals by utilizing the saturated hyperbolic tangent function, (3) compensate the actuator saturation by MLNN controller and (4) a nonlinear saturated observer to estimate robot velocities.

Keywords:

actuator saturation , output feedback control , model uncertainty , trajectory tracking , saturated observer