面向离散地形的欠驱动双足机器人平衡控制方法

Balance Control of Underactuated Biped Robot for Discrete Terrain

欠驱动双足机器人在行走中为保持自身的平衡,双脚需要不间断运动.但在仅有特定立足点的离散地形上很难实现调整后的落脚点,从而导致欠驱动双足机器人在复杂环境中的适应能力下降.提出了基于虚拟约束(Virtual constraint,VC)的变步长调节与控制方法,根据欠驱动双足机器人当前状态与参考落脚点设计了非时变尺度缩放因子,能够实时重构适应当前环境的步态轨迹;同时构建了全身动力学模型,采用反馈线性化的模型预测控制(Model predictive control,MPC)滚动优化产生力矩控制量,实现准确的轨迹跟踪控制.最终进行了欠驱动双足机器人的随机离散地形稳定行走的仿真实验,验证了所提方法的有效性与鲁棒性.

To keep the balance of the underactuated biped robot during walking, its feet need to move continuously. However, it is difficult to achieve the adjusted foothold on the discrete terrain with only a specific foothold,which decreases the adaptability of underactuated biped robots in complex environments. This paper proposes a variable step-size adjustment and control method based on virtual constraints(VC). Time-invariant scaling factors are designed according to the underactuated biped robot’s current state and reference point, which can reconstruct the gait trajectory by adapting to the current environment in real-time. Meanwhile, the whole body dynamics model is constructed. The torque control is generated by rolling optimization using model predictive control(MPC) with feedback linearization to achieve accurate trajectory tracking control. Finally, an underactuated biped robot walking stably on random discrete terrain is simulated to verify the effectiveness and robustness of the proposed method.