Arctangent-Based Extended State Observer with Terminal Attractor

Aiming at the numerous adjustable parameters, poor chattering attenuation ability and unsystematic parameter tuning method of arctangent-based extended state observer (AESO), an arctangent-based extended state observer with terminal attractor (AESOT) is designed. By introducing the terminal attractor in sliding mode control, ESO could obtain a better interference rejection ability and a fewer quantity of adjustable parameters. Then, the parameter tuning method of AESOT is summarized by frequency domain analysis. Finally, the simulations include the testing for the estimated ability with the measurement noise and a typical application for AESOT in aircraft pitch angle controller. The simulation results show that the estimated ability, disturbance rejection ability and chattering attenuation ability for the second-order signal and disturbing signal of AESOT are better. And AESOT can be applied in the pitch angle controller.