论文标题
具有差异性层次任务控制的工业操纵器的实时模型预测控制
Real-Time Model Predictive Control for Industrial Manipulators with Singularity-Tolerant Hierarchical Task Control
论文作者
论文摘要
本文提出了一种实时模型预测控制(MPC)方案,以使用有限的时间范围内的机器人执行多个任务。在工业机器人应用中,我们必须仔细考虑避免关节位置,速度和扭矩限制的多个限制。此外,无奇异性和平稳的动作需要连续,安全地执行任务。我们没有制定非线性MPC问题,而是使用沿层次控制器产生的名义轨迹线性的运动学模型来设计线性MPC问题。这些线性MPC问题可通过使用二次编程来解决;因此,我们大大减少了提出的MPC框架的计算时间,因此所得更新频率高于1 kHz。与基于操作空间控制(OSC)相比,我们提出的MPC框架在减少任务跟踪错误方面更有效。我们在数值模拟和使用工业操纵器的实际实验中验证方法。更具体地说,我们在机器人物流的两个实用方案中部署方法:1)在考虑扭矩限制的同时控制携带重载的机器人,以及2)控制最终效果,同时避免奇异性。
This paper proposes a real-time model predictive control (MPC) scheme to execute multiple tasks using robots over a finite-time horizon. In industrial robotic applications, we must carefully consider multiple constraints for avoiding joint position, velocity, and torque limits. In addition, singularity-free and smooth motions require executing tasks continuously and safely. Instead of formulating nonlinear MPC problems, we devise linear MPC problems using kinematic and dynamic models linearized along nominal trajectories produced by hierarchical controllers. These linear MPC problems are solvable via the use of Quadratic Programming; therefore, we significantly reduce the computation time of the proposed MPC framework so the resulting update frequency is higher than 1 kHz. Our proposed MPC framework is more efficient in reducing task tracking errors than a baseline based on operational space control (OSC). We validate our approach in numerical simulations and in real experiments using an industrial manipulator. More specifically, we deploy our method in two practical scenarios for robotic logistics: 1) controlling a robot carrying heavy payloads while accounting for torque limits, and 2) controlling the end-effector while avoiding singularities.