No abstract

Feedback linearization is widely used for the purpose of quadrotor control. Unfortunately, feedback linearization is highly sensitive to any quadrotor model uncertainties. This paper provides feedback linearization-based control with robustness by integrating it with a disturbance observer. The proposed approach maintains the simplicity of the control structure without ignoring the high nonlinearities existing in the model by considering these nonlinearities as disturbances to be attenuated by the disturbance observer. Thus, the requirement to include complex high-order Lie derivatives in the controller is eliminated even in the presence of the high nonlinearities. Simulation results show that the proposed controller successfully force the quadrotor to follow the desired position and heading trajectories in the presence of different types of disturbances including ignored nonlinear dynamics, wind disturbances and partial actuator failure.

Cranes are used to move loads from one location to another in minimum time such that the load reaches its destination without swinging. This swinging problem gets aggravated in the presence of external disturbances such as in the case of marine cranes. This paper investigates the modeling of a tower crane model and different types of control schemes for both anti-swaying and input tracking control for the tower crane model under continuous external disturbances. The input shaping technique was applied for a tower crane model under continuous external disturbance. Then a closed-loop PID input shaper was implemented instead of the open-loop input shaper to compensate for the external disturbances. Also the response of the closed-loop PID input shaper was compared to a controller based on inverse dynamics. Environmental disturbances such as sea waves were simulated by the movement of a Stewart platform.