软体仿蛙游动机器人关节式气动致动器研制

Development of a Joint-like Pneumatic Actuator Applied to Soft Frog-inspired Swimming Robot

为实现仿蛙游动机器人的微小型化,增强其环境适应能力,结合软体材料的优势特点和青蛙划动推进的游动方式,提出了一种关节式气动软体致动器,该致动器在满足软体仿蛙机器人游动过程中的运动性能和力学性能的同时,使得其肢体结构更加紧凑、轻量.利用Yeoh本构模型和虚功原理,结合关节式气动软体致动器的几何参数,建立了致动器的形变分析模型.进而,在致动器总体尺寸受约束的情况下,以一定弯曲角度下致动器输出恢复力矩最大为目标,确定了致动器的具体结构参数.融合3D打印、模塑成型等加工工艺方法,加工制备了关节式气动软体致动器,并通过对比分析,确定了采用纤维线限制致动器径向凸起效应时纤维线的绕线形式和绕线密度.最后经过实验测试分析,该致动器质量约7.5g,可实现由180°弯曲状态至伸直状态的形态变化,并且在弯曲角度一定时通过调整充入气压的大小可以匹配一定范围内不同大小的负载力矩,从而验证了针对软体仿蛙游动机器人设计的关节式气动软体致动器的可行性.

In order to realize the miniaturization of the frog-inspired swimming robot and enhance its environmental adaptability, a joint-like pneumatic soft actuator is proposed by combining the superior characteristics of the soft material and the swimming mode of the frog, which can achieve more compact and lighter limb structure, while satisfying the kinematics and mechanical properties during swimming of the soft frog-inspired robot. Based on the Yeoh constitutive model and the virtual work principle, the deformation analysis model of the actuator is established with the geometric parameters of the joint-like pneumatic soft actuator. Furthermore, the output recovery torque of the actuator is maximized at a certain bending angle in the case that the overall size of the actuator is constrained, and the specific structural parameters of the actuator are determined. The joint-like pneumatic soft actuator is fabricated by 3D printing, molding and other processing methods.Through the comparative analysis, the winding form and winding density of the fiber-line are determined to suppress the radial protrusion effect of the actuator. Finally, the experimental test and analysis show that the actuator with a mass of about 7.5 g can perform a morphological change from the 180° bending state to the straightening state, and can match different load torques within a certain range by adjusting the filling air pressure at a certain bending angle. Thus, the feasibility of the joint-like pneumatic soft actuator designed for the soft frog-inspired swimming robot is verified.