仿避役舌弹射结构的多层弹性体嵌套柔性机器人运动机理研究

Flexible robots inspired by the octopus arm or the trunk mainly adopt the winding mode for grasping under unstructured environment, while the research on longitudinal extending motion mode is scarce. Therefore, technical limitations of low speed and efficiency exist in grasping operations. The flexible tongue of chameleon takes advantage of special energy releasing mechanism and performs rapid extension/contraction in longitudinal motion, which provides a new perspective in developing novel continuum robotics. Inspired by the rapid projection mechanism of the chameleon tongue, this project carries out research on biological structure, regulatory principle, biomechanics and motion control strategy of the chameleon tongue to take deep insight into the mechanism of such inherent behaviors; with the elaborate analysis of the biological phenomena of rapid extension/contraction induced by elastic-energy storage/release mechanism, a multi-body elastic nested robot is designed by using equivalent substitution, complex mechanism decoupling and topology analysis; then the parallel active control algorithm for the double modules of native driver and cable type external driver is adopted to develop the extension and contraction motions of the projection robot; via developing physical prototype and carrying out experiments, the motion principle analysis is verified and the function of the tongue-inspired structure is tested with specific control strategy. This research will provide novel theorem and technical support to addressing problems in high-speed grasping under the unstructured environment.

仿章鱼触角、象鼻类器官的柔性机器人较少涉及纵向伸缩运动机理的研究，主要依靠卷绕的方式实现非结构环境下的抓取作业，存在操作速度较慢的局限性，而同是“无脊椎”柔性结构的避役舌器官具备纵向快速伸缩的运动特性为突破这一局限提供了新的研究思路。受避役高速弹舌的启发，通过对避役弹舌的生理结构、作用机理、生物力学及运动调控机制等方面开展研究，揭示舌器官具备优异性能深层次原因；深入分析舌内鞘能量快速储存/释放机制促发肌体快速伸展/收缩形变的生理构造，综合采用等效功能替代、复杂机构解耦、拓扑结构分析等方法设计一种多单元弹性嵌套结构机器人；采用物态相变驱动和绳索驱动的混合双单元并行主动调控方法实现机器人的快速伸缩运动；通过开发物理样机验证对“弹舌”运动机理分析的正确性、仿生机构设计的合理性以及调控策略的有效性进行验证。本研究成果为突破非结构化环境下机器人柔性高速抓取研究瓶颈提供新的理论依据和技术支撑。

传统的刚性结构抓取机器人在非结构环境下完成远距离抓取作业时，存在本体不可移动、不具备伸展能力、环境适应性较差等局限性。避役高速、远距离弹舌的运动特性为突破这一局限提供了新的研究思路。避役捕食过程中舌头瞬间释放巨大的能量，以高达500m/s2的加速度弹射伸长至身体长度2倍的距离。受避役弹舌运动以及其舌器官生理结构的启发，提出一种模拟避役舌弹射能力的仿生弹射机器人。首先，分析避役舌器官的构成以及其高速弹射的运动机理，并建立弹射机构的简化物理模型，并进行基于MATLAB的动力学仿真分析；其次，基于多层弹性体嵌套结构建立弹射机器人的三维结构模型，并应用SolidWorks进行结构的运动学仿真分析；最后，完成该机器人样机的零件加工、组装和调试，并进行样机弹射试验。通过试验数据的采集处理，与仿真结果进行对比分析发现：该弹射机器人的弹射加速度能达到6653m/s2，最大弹射速度达到15m/s，且最大伸展距离约0.44m，为初始状态的2.6倍。结果表明该仿生弹射机器人的弹射速度和加速度都较高，验证了仿生弹射机器人的结构设计的有效性。本研究通过生物、力学、机械、材料、电子、控制等多学科交叉与融合，发明一种新型的机器人弹射抓取模式，显著提高机器人的抓取性能。