Task-dependent controllers widely used in exoskeletons track predefined trajectories, which overly constrain the volitional motion of individuals with remnant voluntary mobility. Energy shaping, on the other hand, provides task-invariant assistance by altering the human body's dynamic characteristics in the closed loop. While human-exoskeleton systems are often modeled using Euler-Lagrange equations, in our previous work we modeled the system as a port-controlled-Hamiltonian system, and a task-invariant controller was designed for a knee-ankle exoskeleton using interconnection-damping assignment passivity-based control. In this paper, we extend this framework to design a controller for a backdrivable hip exoskeleton to assist multiple tasks. A set of basis functions that contains information of kinematics is selected and corresponding coefficients are optimized, which allows the controller to provide torque that fits normative human torque for different activities of daily life. Human-subject experiments with two able-bodied subjects demonstrated the controller's capability to reduce muscle effort across different tasks.

翻译：任务依赖型控制器广泛用于外骨骼中，通过跟踪预定义轨迹来辅助运动，但这过度约束了具有残余自主运动能力的个体的意愿性运动。而能量整形控制通过改变人体在闭环中的动态特性，提供与任务无关的辅助。虽然人-外骨骼系统常使用欧拉-拉格朗日方程建模，但我们在先前工作中将该系统建模为端口受控哈密顿系统，并利用互连-阻尼分配无源控制方法为膝踝外骨骼设计了任务无关控制器。本文将该框架扩展至可回驱髋关节外骨骼的控制器设计，以辅助多种任务。我们选取一组包含运动学信息的基函数并优化对应系数，使控制器能够生成适配不同日常生活活动的规范人体力矩。两名健康受试者的人体实验表明，该控制器可在不同任务中降低肌肉做功。