Nonlinear model predictive control with set terminal constraint for safe robot motion planning via speed and separation monitoring

IF 5.4 2区计算机科学 Q1 AUTOMATION & CONTROL SYSTEMS

Control Engineering Practice Pub Date : 2024-11-08 DOI:10.1016/j.conengprac.2024.106155

Aigerim Nurbayeva, Matteo Rubagotti

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Abstract

This paper proposes a methodology for safely planning the motion of a robot manipulator sharing its workspace with a human operator. The motion of the robot is continuously re-planned via nonlinear model predictive control (NMPC), imposing the so-called speed and separation monitoring (SSM) condition to guarantee human safety. Contrary to previous works in the field, the NMPC algorithm is designed with an ellipsoidal terminal constraint, to enlarge the domain of attraction compared to the case in which a point terminal constraint was imposed. This is a very important aspect in real-world applications, allowing the robot to plan its motion from initial configurations that are relatively far from the goal point. Theoretical results are proved on recursive feasibility and closed-loop stability for both cases of NMPC with point and set terminal constraints, under the simplifying assumption of a static human. The effectiveness of the proposed approach is verified via numerical evaluation of the domain of attraction and with experiments on a UR5 manipulator.

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非线性模型预测控制与设定终端约束，通过速度和分离监控实现安全的机器人运动规划

本文提出了一种方法，用于安全规划与人类操作员共享工作空间的机器人机械手的运动。通过非线性模型预测控制（NMPC）不断重新规划机器人的运动，并施加所谓的速度和分离监控（SSM）条件，以确保人类安全。与该领域以前的工作不同，NMPC 算法设计了一个椭圆形终端约束，与施加点终端约束的情况相比，扩大了吸引域。这在实际应用中是非常重要的，它允许机器人从离目标点相对较远的初始配置开始规划运动。在人类静态的简化假设下，证明了带有点和集合终端约束的 NMPC 两种情况下的递归可行性和闭环稳定性的理论结果。通过对吸引域进行数值评估以及在 UR5 机械手上进行实验，验证了所提方法的有效性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Control Engineering Practice 工程技术-工程：电子与电气

CiteScore

9.20

自引率

12.20%

发文量

183

审稿时长

44 days

期刊介绍： Control Engineering Practice strives to meet the needs of industrial practitioners and industrially related academics and researchers. It publishes papers which illustrate the direct application of control theory and its supporting tools in all possible areas of automation. As a result, the journal only contains papers which can be considered to have made significant contributions to the application of advanced control techniques. It is normally expected that practical results should be included, but where simulation only studies are available, it is necessary to demonstrate that the simulation model is representative of a genuine application. Strictly theoretical papers will find a more appropriate home in Control Engineering Practice''s sister publication, Automatica. It is also expected that papers are innovative with respect to the state of the art and are sufficiently detailed for a reader to be able to duplicate the main results of the paper (supplementary material, including datasets, tables, code and any relevant interactive material can be made available and downloaded from the website). The benefits of the presented methods must be made very clear and the new techniques must be compared and contrasted with results obtained using existing methods. Moreover, a thorough analysis of failures that may happen in the design process and implementation can also be part of the paper. The scope of Control Engineering Practice matches the activities of IFAC. Papers demonstrating the contribution of automation and control in improving the performance, quality, productivity, sustainability, resource and energy efficiency, and the manageability of systems and processes for the benefit of mankind and are relevant to industrial practitioners are most welcome.