Quintero David, Villarreal Dario J, Lambert Daniel J, Kapp Susan, Gregg Robert D
Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080 USA.
Department of Mechanical Engineering, University of Texas at Dallas, Richardson, TX 75080 USA.
IEEE Trans Robot. 2018 Jun;34(3):686-701. doi: 10.1109/TRO.2018.2794536. Epub 2018 Feb 27.
Control systems for powered prosthetic legs typically divide the gait cycle into several periods with distinct controllers, resulting in dozens of control parameters that must be tuned across users and activities. To address this challenge, this paper presents a control approach that unifies the gait cycle of a powered knee-ankle prosthesis using a continuous, user-synchronized sense of phase. Virtual constraints characterize the desired periodic joint trajectories as functions of a phase variable across the entire stride. The phase variable is computed from residual thigh motion, giving the amputee control over the timing of the prosthetic joint patterns. This continuous sense of phase enabled three transfemoral amputee subjects to walk at speeds from 0.67 to 1.21 m/s and slopes from -2.5 to +9.0 deg. Virtual constraints based on task-specific kinematics facilitated normative adjustments in joint work across walking speeds. A fixed set of control gains generalized across these activities and users, which minimized the configuration time of the prosthesis.
动力假肢腿的控制系统通常将步态周期划分为几个阶段，并使用不同的控制器，这就产生了几十个控制参数，必须针对不同用户和活动进行调整。为应对这一挑战，本文提出了一种控制方法，该方法利用连续的、与用户同步的相位感知来统一动力膝-踝假肢的步态周期。虚拟约束将期望的周期性关节轨迹表征为整个步幅中相位变量的函数。相位变量由残留的大腿运动计算得出，使截肢者能够控制假肢关节模式的时间。这种连续的相位感知使三名经大腿截肢的受试者能够以0.67至1.21米/秒的速度行走，坡度范围为-2.5至+9.0度。基于特定任务运动学的虚拟约束有助于在不同步行速度下对关节功进行规范调整。一组固定的控制增益适用于这些活动和用户，从而将假肢的配置时间降至最低。
