Pi Ming
School of Information and Control Engineering, Southwest University of Science and Technology, Mianyang 621000, China.
Sensors (Basel). 2025 Aug 12;25(16):4975. doi: 10.3390/s25164975.
By sensing changes in the contact force between the leg and level ground, humans can perceive their walking speed and adjust leg stiffness to accommodate walking terrains. To realize this natural regulation mechanism on the lower limb amputee, noninvasive functional electrical stimulation (nFES) was used to assist the subject in sensing the change in contact force between the leg and level ground, allowing for the adjustment of control parameters in the prosthetic leg. The cost function was designed to combine the tracking errors of the joints and changes in the stimulating current. For different walking terrains, an extremum-seeking control (ESC) method was employed to search for suitable control parameters in real time by monitoring the changes in the cost function. The stability of the proposed controller with extremum-seeking dynamics was demonstrated. The experimental results demonstrated that the extremum-seeking method effectively adjusted the control parameters of the prosthetic leg in response to changes in the cost function.
通过感知腿部与水平地面之间接触力的变化，人类能够感知自己的行走速度，并调整腿部刚度以适应行走地形。为了在下肢截肢者身上实现这种自然调节机制，采用了无创功能性电刺激（nFES）来辅助受试者感知腿部与水平地面之间接触力的变化，从而能够调整假肢的控制参数。成本函数被设计为结合关节的跟踪误差和刺激电流的变化。对于不同的行走地形，采用极值搜索控制（ESC）方法，通过监测成本函数的变化实时搜索合适的控制参数。证明了所提出的具有极值搜索动态特性的控制器的稳定性。实验结果表明，极值搜索方法能够根据成本函数的变化有效地调整假肢的控制参数。
