通过刚度编码生成具有稳定特性的动力系统,提升机器人控制可靠性。
Generation of Conservative Dynamical Systems Based on Stiffness Encoding
- 用刚度编码调控动力系统特性,实现对运动行为的精确控制。
- 生成的动力系统具备对称吸引性和可变刚度,闭环系统始终被动。
- 适用于复杂轨迹,尤其适合需要高稳定性的机器人控制场景。
动力系统(DS)为运动规划和人机交互提供了高灵活性、鲁棒性与控制可靠性,其性质直接决定机器人的运动模式与闭环控制性能。本文建立了刚度特性与动力系统之间的定量关系,提出一种刚度编码框架,通过嵌入特定刚度来调节动力系统特性。从闭环控制系统的无源性出发,通过编码保守刚度学习得到保守动力系统,其具有对称吸引行为和可变刚度分布。该方法适用于不同流形与类型的演示轨迹(如闭合及自交轨迹),在各类情况下均能保证闭环系统被动。对于跟踪一般动力系统的控制器,需通过能量罐保障系统无源性;为此,我们进一步提出基于保守刚度的通用矢量场分解策略,有效减缓能量罐中能量衰减速率,提升控制系统的稳定性裕度。一系列仿真及平面与曲线运动任务的实验验证了理论与方法的有效性。
原文摘要 · Abstract (English)
Dynamical systems (DSs) provide a framework for high flexibility, robustness, and control reliability and are widely used in motion planning and physical human-robot interaction. The properties of the DS directly determine the robot's specific motion patterns and the performance of the closed-loop control system. In this paper, we establish a quantitative relationship between stiffness properties and DS. We propose a stiffness encoding framework to modulate DS properties by embedding specific stiffnesses. In particular, from the perspective of the closed-loop control system's passivity, a conservative DS is learned by encoding a conservative stiffness. The generated DS has a symmetric attraction behavior and a variable stiffness profile. The proposed method is applicable to demonstration trajectories belonging to different manifolds and types (e.g., closed and self-intersecting trajectories), and the closed-loop control system is always guaranteed to be passive in different cases. For controllers tracking the general DS, the passivity of the system needs to be guaranteed by the energy tank. We further propose a generic vector field decomposition strategy based on conservative stiffness, which effectively slows down the decay rate of energy in the energy tank and improves the stability margin of the control system. Finally, a series of simulations in various scenarios and experiments on planar and curved motion tasks demonstrate the validity of our theory and methodology.
Thank you to arXiv for use of its open access interoperability. PaperDance 不是 arXiv 官方产品;中文卡片由大模型生成,请以原文为准。