Abstract: The multi-cavity soft actuator is assembled from single-cavity soft actuator through a reasonable geometric distribution. It has the characteristic that the pneumatic soft actuator is driven by its own deformation and has more degrees of freedom. Pneumatic soft actuator is widely used as an emerging discipline and its strong compliance has been greatly developed and applied. However, as the most application potential type of soft actuators, there is still a lack of simple and effective deformation prediction methods for studying the spatial deformation of multi-cavity soft actuators. To solve this problem, a vector equation method is proposed based on the analysis of the principle of the space deformation of the two-cavity, three-cavity and four-cavity soft actuators. Furthermore, a nonlinear mathematical model of the air pressure, space position and deformation trajectory of the soft actuator end is established by combining the vector equation method. Finally, the three-channel soft actuator is verified through experiments. The results show that the mathematical model can better predict the space deformation trajectory of the soft actuator, which provides a new research method for studying the space deformation of the multi-channel soft actuator.

Key words: soft actuator, multi-cavity soft, vector equation method, finite element simulation