Yeatman Mark, Lv Ge, Gregg Robert D
Department of Mechanical Engineering, University of Texas at Dallas, Richardson, TX 75080.
Department of Electrical Engineering, University of Texas at Dallas, Richardson, TX 75080.
J Dyn Syst Meas Control. 2019 Oct;141(10):1010071-10100711. doi: 10.1115/1.4043801. Epub 2019 Jun 13.
This paper details a decentralized passivity-based control (PBC) to improve the robustness of biped locomotion in the presence of gait-generating external torques and parametric errors in the biped model. Previous work demonstrated a passive output for biped systems based on a generalized energy that, when directly used for feedback control, increases the basin of attraction and convergence rate of the biped to a stable limit cycle. This paper extends the concept with a theoretical framework to address both uncertainty in the biped model and a lack of sensing hardware, by allowing the designer to neglect arbitrary states and parameters in the system. This framework also allows the control to be implemented on wearable devices, such as a lower limb exoskeleton or powered prosthesis, without needing a model of the user's dynamics. Simulations on a six-link biped model demonstrate that the proposed control scheme increases the convergence rate of the biped to a walking gait and improves the robustness to perturbations and to changes in ground slope.
本文详细介绍了一种基于分散无源控制（PBC）的方法，以提高双足机器人在存在步态生成外部扭矩和双足模型参数误差的情况下的运动鲁棒性。先前的工作基于广义能量展示了双足系统的一个无源输出，当直接用于反馈控制时，该输出会增加双足机器人到稳定极限环的吸引域和收敛速度。本文通过一个理论框架扩展了这一概念，通过允许设计者忽略系统中的任意状态和参数来解决双足模型中的不确定性和传感硬件的缺乏问题。该框架还允许在可穿戴设备（如下肢外骨骼或动力假肢）上实现控制，而无需用户动力学模型。在一个六连杆双足模型上的仿真表明，所提出的控制方案提高了双足机器人到步行步态的收敛速度，并提高了对扰动和地面坡度变化的鲁棒性。
