仿生机器鱼高效推进的主动/被动控制机理研究

By deeply analyzing the propulsion mechanism and the conventional control algorithm of the biomimetic robotic fish, we now propose an active/passive control strategy with high-efficient propulsion, which aims at obtaining high thrust efficiency and improving the cruising ability of the robotic fish. The relationship among the thrust performance, the stiffness and the thrust efficiency of the robotic fish is first discussed from the perspective of negative work. Then we introduce a compliant control algorithm based on the virtual muscle, which combines the active plan and the passive adjustment, to improve the thrust efficiency. This project is based on the propulsion mechanism revealed from the negative work of the muscle in real fish. With the aid of a novel self-propulsion test bench, some researches, including the variable stiffness driving method of the actuator, the negative work model of the robotic fish and the active/passive compliant control strategy, are studied. Meanwhile the actuator with variable stiffness, the control system based on FPGA and the high thrust efficiency knowledge database based on the negative work are designed in this project. At last, the free-swimming platform of the robotic fish is designed to optimize the parameter and validate the control strategy proposed above. In this project, we will explore the new control idea and its research method to make an innovation and a breakthrough in the key techniques as well as to promote the development of the biomimetic robotic fish and relevant disciplines.

深入研究了仿生机器鱼的推进机理和控制方法，针对现有机器鱼推进效率低下、续航时间短的关键问题，提出了一种高效推进的主动/被动控制方法；首次从负功角度讨论机器鱼的运动参数、刚度和推进效率之间的关系，引入虚拟肌肉的柔顺控制思想，融合主动规划和被动调节，提高机器鱼的推进效率。课题以生物鱼游动中肌肉的负功状态所揭示的推进机理为基础，在自主推进测试平台的实验条件下，研究关节电机的变刚度驱动方法、机器鱼负功状态的模型辨识以及主动/被动柔顺控制算法；并针对提出的算法开发虚拟肌肉的变刚度驱动器和基于FPGA多异质阵列的主-从结构控制系统，建立基于负功的高效推进知识库，设计自由游动机器鱼样机平台进行算法优化和实验验证。项目的主要意义是探索新的控制思路及相应的研究方法，以求在关键技术上有所突破和创新，并推动仿生机器鱼技术和相关学科的研究和发展。

课题针对限制机器鱼应用的瓶颈问题，以提高推进效率为研究目标，主要进行了仿生机器鱼的运动学建模、动力学建模、水动力建模、推进效率评估方法、关节变刚度方法、基于负功高效推进方法及机器鱼样机研制方面的工作。在推进效率的评估方面，我们分析了生物鱼的运动规律，以此得到了两关节机器鱼的运动学模型，利用拉格朗日方程建立了两关节机器鱼的动力学模型，利用简化的公式得到了机器鱼的水动力模型；在刚度变化方面，我们从柔顺控制的角度出发，探索了基于虚拟肌肉模型实现关节变刚度的方法，提出了在位置闭环的控制中通过改变比例控制系数来改变刚度的方法；在高效推进方面，针对当前机器鱼推进效率较低的问题，我们基于生物学家对生物鱼负功的阐述，利用仿真分析的手段探索了利用关节负功改变关节刚度的控制方法，实验结果表明，利用该方法驱动关节能够提高机器鱼的推进效率；在实际的机器鱼样机的研制方面，我们分析了机器鱼的控制步骤，基于此利用ARM处理器开发了小体积的机器鱼多关节控制器。目前共发表SCI期刊5篇，EI论文3篇，申请发明专利2项，制作了机器鱼样机一台。