Amplitude-saturated control of underactuated double-pendulum tower cranes: Design and experiments

Abstract

In practical industrial transportation applications, tower cranes play a crucial role. However, the existing control methods for tower cranes often overlook the double-pendulum effect or only consider the linearized double-pendulum dynamic model. To address these issues, for double-pendulum tower cranes, this paper proposes an amplitude-saturated nonlinear control method without velocity measurement. This design approach does not require any linearization operation and effectively eliminates the effect of steady-state error through elaborately constructed composite variables. The theoretical analysis guarantees that the controller can effectively suppress load oscillation and satisfy input constraints. Furthermore, it is proved that the state variables of the closed-loop system can asymptotically converge to the equilibrium point by means of Lyapunov theorem and LaSalle’s invariance principle. Finally, experimental results are provided to validate the feasibility of the proposed method.