直立抗扰任务下的踝关节外骨骼协作控制策略研究

In the field of human-exoskeleton interaction, the complexity of “human-in-the-loop” and diversities of tasks impose great challenges on exoskeleton control modeling, which consequently leads to an unpromising cooperation performance between exoskeleton and human. Starting from interaction between human and single-joint exoskeleton under simple task, the project concentrates its research interest on studying the cooperative control strategy of ankle exoskeleton under human push-recovery task. The main consideration of the project is to enhance the cooperative performance between human and ankle exoskeleton via bionic and optimization. . The following three parts will be investigated in the project：1) the impedance properties of human ankle joint; 2) the impedance-based cooperation control strategy of ankle exoskeleton; 3) the dynamical allocation discipline of impedance between human ankle joint and ankle exoskeleton. . The project commits to solving the following two key issues: 1) the fast response mechanism involved in human ankle under push-recovery task; 2) the establishment of an optimization framework for the ankle exoskeleton cooperative control strategy. . The main contributions of the project are: 1) a human-inspired reflex control loop is inserted into the impedance control strategy of the ankle exoskeleton to enhance the response speed of the exoskeleton; 2)a newly-developed method based on human compensatory function detection is proposed to establish the objective function for optimizing the cooperative control stratetegy of the ankle exoskeleton under the push-recovery task. . The expected research results of the project would not only promote the development of human-exoskeleton interaction of multiple-joint exoskeleton under some complicated tasks, but also suggest some clues of the bionic study of lower-limb robotics.

人与外骨骼交互过程的复杂性源自两个方面：人在回路中，但建模极其困难；协作任务变化多样，建模同样困难；最终导致人机协作效果不理想。本项目从简单任务下单关节外骨骼的人机协作出发，研究直立抗扰任务下踝关节外骨骼的协作控制，通过仿生和优化两个手段，获取最佳协作控制策略。主要研究：1)直立抗扰过程中人体踝关节阻抗特性；2)基于阻抗的踝关节外骨骼协作控制策略；3)直立抗扰时人与外骨骼的阻抗分配规律。重点解决：1)直立抗扰过程中人体踝关节的快速响应机制；2)直立抗扰辅助用踝关节外骨骼控制策略的优化框架。创新点在于：1)在外骨骼阻抗控制策略中加入仿人体关节的反射控制环节，以提高外骨骼快速响应能力；2)基于人体代偿行为的监测，为直立抗扰任务下外骨骼人机协作控制策略的优化建立目标函数。本项目的结果将为复杂任务下多关节外骨骼人机协作研究奠定基础，推动外骨骼相关研究进展，并为机器人下肢的仿生控制研究提供理论支撑。

辅助人体直立抗扰时，外骨骼与人紧密耦合，形成一个完整闭环系统，可提升人体抗扰能力。但在两者交互过程中，人体抗扰机制的关节控制机理及其复杂，往往导致交互效果不理想，增加了研究难度。本项目从人机协作出发，研究直立抗扰任务下踝关节外骨骼的协作控制，通过仿生和优化两个手段，获取最佳协作控制策略。主要研究：1)直立抗扰过程中人体踝关节阻抗特性；2)基于阻抗的踝关节外骨骼协作控制策略；3)直立抗扰时人与外骨骼的阻抗分配规律。为此，通过仿生与优化手段，首先建立基于阻抗的外骨骼控制策略，然后，建立“人在回路”优化框架对外骨骼阻抗控制策略进行控制参数寻优，为每个穿戴者找到合适的外骨骼控制参数，解决外骨骼控制参数个性化设计的难题。实验结果表明本项目提出的方法不仅解决了外骨骼控制参数个性化设计的难题，还能够有效降低人体直立抗扰的能量消耗，提高人体直立抗扰效能。因此，本项目提出的方法有望为复杂任务下多关节外骨骼人机协作研究奠定基础，推动外骨骼相关研究进展，并为机器人下肢的仿生控制研究提供理论支撑。