Slosh suppression for infinite modes in a moving liquid container

Control of a moving liquid container is challenging because of unwanted transient and residual slosh. Although significant progress has been achieved at eliminating the fundamental sloshing mode, less success has been achieved with designing a controller to suppress slosh for an infinite number of modes. This study presented two methods to reduce an infinite number of sloshing modes in a moving liquid container. The first method is command smoothing to eliminate slosh by using the first-mode frequency. The second one is a combined input-shaping and command-smoothing architecture. The input shaper reduces slosh for the first mode, while the command smoother suppresses slosh for the third and higher modes. Both the command smoothing and the combined control scheme eliminate the transient and residual slosh to a very low level. However, the rise time of the combined controller is shorter than that of the command smoother. Simulations of a large range of motions are used to analyze liquid sloshing dynamics by using the proposed methods. Experimental results obtained from a moving container validate the simulated dynamic behavior and the effectiveness of the methods.