全方位移动机械手运动控制Ⅰ——建模与控制

Motion Control of Omnidirectional Mobile Manipulators (PartⅠ)——Modeling and Control

针对一类由轮式驱动全方位移动平台和机械臂所组成的全方位移动机械手,首先通过对机械结构和运动特性的分析,建立一体化运动学模型,并利用拉格朗日力学法建立动力学模型,分析这两种模型的运动性质。然后根据所建立的模型,分别设计轨迹跟踪控制器,并对控制器的稳定性予以证明。在基于动力学模型的轨迹跟踪控制器中,通过结合全方位移动平台的运动学模型和全方位移动机械手的动力学模型,定量地分析移动平台运动状态对机械臂的耦合作用,并在相应的轨迹跟踪控制器中予以补偿。仿真结果不仅显示所提出两种模型的正确性和相应轨迹跟踪控制器的有效性,而且也说明所述方法可以作为一类移动机械手通用的建模和控制方法。

Aiming at a certain kind of omnidirectional mobile manipulators, which generally consist of an omnidirectional mobile platform driven by wheels and a robot arm, an integrated kinematics model is built based on the mechanical structure and motion properties of the omnidirectional mobile manipulator. In addition, its dynamic model is deduced by Lagrangian formalism. In terms of the proposed models, two tracking controllers are designed subsequently. Stability analyses of the proposed controllers are also given. Especially in the tracking controller based on the dynamic model, the coupling torque between the mobile platform and the robot arm is analyzed quantitatively, and compensated in the tracking controller. Simulation results show the correctness of the proposed models and the effectiveness of the control approaches, and indicate that the research can be a general method for modeling and controlling a certain kind of mobile manipulators.