八索立式储罐并联机器人设计及性能优化

Design and Analysis of a Wire-Dirven Parallel Mechanism for Large Vertical Storage Tank

针对石油化工行业中广泛应用的大型立式储罐检修任务,传统的脚手架、导轨及爬壁机器人等工作平台存在拆装困难、结构复杂或运行速度较低等缺点,有效载荷能力和工作效率受限制。索并联机构具有工作空间大、承载能力强、模块化等优点,在大型立式储罐的检修领域极具应用潜力。提出一种采用四根支撑杆的八索驱动并联机器人工作平台及出索点位置可调的模块化支撑杆设计;建立了索并联机构的运动学模型和平面简化模型,分析机构参数对其工作空间的影响,并针对20 m口径典型立式储罐给出了优化结构参数;结合索牵引并联机器人的工作平台沿不同轨迹运动时索长、索力变化分析,确定了运动规划时优选运动轨迹。

Traditional working platforms for the maintenance work of large vertical storage tank such as scaffolding, rail and wall-climbing robots have many disadvantages like difficulty on disassembly, complex system or the low moving speed etc. These affect the efficiency of maintenance and limit the payload of working platform. Wire-driven parallel mechanism is new kind of robots with the advantages of large workspace, modular structure and big load capacity, which mean that it is promising to use it as working platform of large vertical storage tank. A new modular wire-driven parallel mechanism is proposed. Depending on the basic theory of parallel mechanism and modular design, the robot has eight wires and four modular rods. The position of each wire on rod is adjustable. After establishing the kinematic model, the influence on workspace by each parameter is given, which make it possible to optimize structure parameters for vertical storage tank of 20 m diameter. While the platform moves along different trajectory, analysis on the change of wire length and wire force shows better motion planning trajectory.