Due to the outstanding characteristics of the large structural flexibility and strong dexterity of soft robots, they have attracted great attention. However, the dynamic modeling and precise control of soft robots face huge challenges. Traditional model-based and model-free control methods find it difficult to obtain a balance between complexity and accuracy. In this paper, a dynamic model of a three-chamber continuous pneumatic manipulator is established based on the modal method. Moreover, a hybrid controller integrating model predictive control (MPC) and iterative learning control (ILC) is proposed, which can simultaneously perform model parameter learning and trajectory tracking control. Experimental results show that the proposed control method can optimize the parameters of the dynamic model in real time with less iterations than the traditional model-free method and have good control performance in trajectory tracking experiments. In the future, the proposed dynamic model and the hybrid controller should be verified on a multi-section manipulator.

The effects of SiC particles on the morphologies, microstructures, and mechanical properties of tungsten inert gas welded AZ31 magnesium alloy joints with TiO 2 flux coating were studied. The results showed that an increase in the amount of the TiO 2 coating improved the weld penetration and the depth/width (D/W) ratio of the TIG welded AZ31 magnesium alloy seams. The a-Mg grains of FZ of welded joints refined gradually with the addition of micro-sized SiC (<30%) =nano-sized SiC (<40%) particles in coatings, and then coarsened when more SiC particles added. In addition, the microhardness of the FZ and ultimate tensile strength of the welded joints increased with the addition of SiC particles, and nano-sized particles have more strong efficiency on the improvement of mechanical properties compared with micro-sized SiC particles.

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