Virtual slope control of a forward dynamic bipedal walker.
Virtual slope control of a forward dynamic bipedal walker.
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DOI：
10.1115/1.1835358
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发表时间：
2005-02
期刊：
影响因子：
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通讯作者：
Shawn Russell;K. Granata;P. Sheth
中科院分区：
文献类型：
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作者：
Shawn Russell;K. Granata;P. Sheth
主动关节扭矩是动态行走运动的动力和控制的主要来源。然而，实现自然稳定性能所需的关节扭矩的幅度、速率、时间和相位行为很难确定。本研究的目的是证明主动控制双足行走模拟的可行性和稳定行为，其中自然系统动力学由被动下坡行走后形成的主动、非线性、状态反馈控制器保留。通过在髋关节和站立腿踝关节处施加主动关节扭矩来实现二自由度的前向动态模拟。主动步行者产生的运动轨迹与被动动态步行相似，主动关节扭矩受规定步行速度的影响。该控制产生稳定的稳态步态模式，即步幅函数的特征值大小小于 1。修改类似于虚拟坡度的控制器系数以成功控制平均行走速度。未来的发展需要扩大步行速度的范围。
Active joint torques are the primary source of power and control in dynamic walking motion. However the amplitude, rate, timing and phasic behavior of the joint torques necessary to achieve a natural and stable performance are difficult to establish. The goal of this study was to demonstrate the feasibility and stable behavior of an actively controlled bipedal walking simulation wherein the natural system dynamics were preserved by an active, nonlinear, state-feedback controller patterned after passive downhill walking. A two degree-of-freedom, forward-dynamic simulation was implemented with active joint torques applied at the hip joints and stance leg ankle. Kinematic trajectories produced by the active walker were similar to passive dynamic walking with active joint torques influenced by prescribed walking velocity. The control resulted in stable steady-state gait patterns, i.e. eigenvalue magnitudes of the stride function were less than one. The controller coefficient analogous to the virtual slope was modified to successfully control average walking velocity. Furture developments are necessary to expand the range of walking velocities.