A Constructive Method for Designing Safe Multirate Controllers for Differentially-Flat Systems
A Constructive Method for Designing Safe Multirate Controllers for Differentially-Flat Systems
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DOI：
10.1109/lcsys.2021.3136465
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发表时间：
2024-03
影响因子：
3
通讯作者：
Devansh R. Agrawal;Hardik Parwana;Ryan K. Cosner;Ugo Rosolia;A. Ames;Dimitra Panagou
中科院分区：
文献类型：
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作者：
Devansh R. Agrawal;Hardik Parwana;Ryan K. Cosner;Ugo Rosolia;A. Ames;Dimitra Panagou
我们提出了一个多速率控制架构，利用微分平坦的基本属性来合成安全关键非线性动力系统的控制器。我们提出了一个两层的架构，其中高级别使用线性模型预测控制器生成参考轨迹，低级别使用反馈控制器跟踪此参考。新颖之处在于我们如何耦合这些层，以实现形式保证MPC问题的递归可行性和非线性系统的安全性。此外，使用微分平坦，我们提供了一个建设性的手段来合成多速率控制器，从而消除了需要寻找合适的李雅普诺夫或障碍函数，或近似线性化/离散化非线性动力学。我们表明，合成控制器是一个凸优化问题，使其适合实时实现。该方法在地面漫游车和四足机器人系统上进行了实验验证。
We present a multi-rate control architecture that leverages fundamental properties of differential flatness to synthesize controllers for safety-critical nonlinear dynamical systems. We propose a two-layer architecture, where the high-level generates reference trajectories using a linear Model Predictive Controller, and the low-level tracks this reference using a feedback controller. The novelty lies in how we couple these layers, to achieve formal guarantees on recursive feasibility of the MPC problem, and safety of the nonlinear system. Furthermore, using differential flatness, we provide a constructive means to synthesize the multi-rate controller, thereby removing the need to search for suitable Lyapunov or barrier functions, or to approximately linearize/discretize nonlinear dynamics. We show the synthesized controller is a convex optimization problem, making it amenable to real-time implementations. The method is demonstrated experimentally on a ground rover and a quadruped robotic system.