Multi-Rate Control Design Under Input Constraints via Fixed-Time Barrier Functions
Multi-Rate Control Design Under Input Constraints via Fixed-Time Barrier Functions
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DOI：
10.1109/lcsys.2021.3084322
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发表时间：
2021-03
影响因子：
3
通讯作者：
Kunal Garg;Ryan K. Cosner;Ugo Rosolia;A. Ames;Dimitra Panagou
中科院分区：
文献类型：
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作者：
Kunal Garg;Ryan K. Cosner;Ugo Rosolia;A. Ames;Dimitra Panagou
在这封信中，我们引入了周期性安全的概念，它要求系统轨迹定期访问前向不变安全集的子集，并在多速率框架中使用它，其中高级规划器生成参考轨迹，由低级控制器在输入约束下跟踪该参考轨迹。我们引入了固定时间势垒函数的概念，该概念由二次规划框架中所提出的低级控制器利用。然后，我们设计了一种用于高层规划的模型预测控制策略，其对参考轨迹的变化率进行了限制，以保证实现周期性安全。我们在仿真示例中证明了所提出策略的有效性，其中所提出的固定时间稳定低级控制器显示出成功满足控制目标，而指数稳定低级控制器则失败。
In this letter, we introduce the notion of periodic safety, which requires that the system trajectories periodically visit a subset of a forward-invariant safe set, and utilize it in a multi-rate framework where a high-level planner generates a reference trajectory that is tracked by a low-level controller under input constraints. We introduce the notion of fixed-time barrier functions which is leveraged by the proposed low-level controller in a quadratic programming framework. Then, we design a model predictive control policy for high-level planning with a bound on the rate of change for the reference trajectory to guarantee that periodic safety is achieved. We demonstrate the effectiveness of the proposed strategy on a simulation example, where the proposed fixed-time stabilizing low-level controller shows successful satisfaction of control objectives, whereas an exponentially stabilizing low-level controller fails.