基于模块间误差测量解耦的可重构机器人精度补偿研究

The main reasons of actual kinematics model deviating from the theoretical model are numerous modules’ geometrical parameter errors and assembly errors between assembled modules, complicated superposition and coupling relationship as well as the ambiguous mechanism of transferring and mapping process. Seeing that the calibration method based on passive external measurement cannot ideally solve rapid precision compensation problem, which leads to the design intention of reconfigurable robot i.e. high precision work became unavailable after reconfiguration. It was analyzed the reasons of modules errors, interaction modes, errors transfer and mapping process between assembled modules and mechanism of superposition and coupling. It was researched modules type, mapping mechanism between modules error types and modular manipulator pose errors. It’s studied on the classification strategy of modules parameter errors that only need to be calibrated by external off-line measurement and further need to be decoupling by means of on-line measurement. It was on-line measured the modules errors via the multi-sensor technology in order to reduce or eliminate impact of modules error coupling on accuracy. Combining external measurement of module parameters, it accomplished rapid accuracy compensation of reconstructed robot arm pose. This research will provide new ideas for the automatic accuracy compensation of module robot pose error after reconfiguration. Meanwhile it will lay the theoretical and technical foundation for the quick accuracy compensation and could quickly solve key problems so as to promote reconfigurable robots to be widely applied in industrial applications such as precision assembly, minor operations and so on.

可重构机械臂中模块的几何参数误差及模块间装配误差数量众多，叠加耦合关系复杂、传递映射过程机理不清，是导致机器人实际运动学模型偏离理论模型的主要原因。完全依赖外部测量的运动学参数标定方法不能理想解决可重构机器人精度快速补偿问题，导致其重构后即可高精度作业的研究初衷难以实现。分析模块误差成因、作用方式，相互装配模块之间误差传递映射过程、耦合叠加机理，研究模块形式、模块误差形式与模块化机械臂位姿误差之间的映射关系。研究模块参数误差仅需外部离线测量标定和需要进一步在线测量解耦的划分策略，通过多传感器技术对模块间误差在线主动测量，降低或消除误差耦合对精度的影响，结合模块参数的外部测量信息，实现机械臂位姿的快速精度补偿。本项目研究工作可为模块化机器人重构后位姿误差快速补偿的实现提供新思路，解决关键问题，奠定理论和技术基础，促进可重构机器人在精密装配、细微操作等场合下广泛工业应用的实现。

针对模块化可重构机械臂面向任务完成重构后的实际运动学模型偏离理论模型的问题，开展基于模块间参数误差主动测量解耦和模块参数外部标定测量的模块化机械臂精度补偿研究。研制出一套由7个关节模块、6个直角连杆模块，4个平行连杆模块及上位机控制终端组成的模块化可重构机械臂实验系统。根据模块间装配误差在接触平面内的映射关系，提出一种接触平面内模块间位置及姿态误差测量解耦识别方法，研制一套装配误差在线识别接口及试验平台，通过仿真试验和物理试验验证了方法的有效性。基于提出的接口接触平面内位姿误差识别方法，给出一种重构后模块化机械臂位姿精度补偿模型，通过仿真试验对模型的正确性进行验证。根据模块间装配误差在三维空间的位姿关系，提出一种模块间位姿误差解耦识别方法，用于识别任意相互装配模块间位姿误差的3个位置分量及3个姿态分量。基于激光位移传感器及四面体结构，设计一种模块间位姿误差识别解耦接口。提出了基于三坐标测量装置的激光传感器光线方程标定建模方法及接口坐标系建立方法。基于局部指数积法，提出了一种包含关节约束条件的显式形式的模块化机械臂运动学参数标定模型。通过一种6自由度模块化机械臂的运动学参数标定仿真试验和物理试验验证了标定模型的正确性和有效性。针对基于全局指数积法的伴随误差模型所存在的参数更新不简洁、模型表达不统一等问题，提出了一种改进的伴随误差标定方法。分别给出基于末端执行器位姿误差和位置误差的运动学参数标定模型。通过仿真试验和物理试验验证了标定模型的正确性与有效性。本项目研究工作为模块化机器人重构后位姿误差快速补偿的实现提供了新的思路，解决关键理论问题和工程问题，可促进可重构机器人在精密装配、细微操作等场合下广泛工业应用的实现。