自驱动关节臂坐标测量机模块化关节设计

传统的关节臂测量机工作时是依靠工作人员牵拉实现运动和测量,存在路径规划不佳、主观性误差大、测量效率低等问题很难适应智能制造对在线自动测量系统的新要求。本文提出了利用含有无刷电机、谐波减速器及精密轴系的模块化关节构成自驱动关节臂坐标测量机的构想,并对模块化关节进行了构型设计,建立了单关节扭矩估算模型,在此基础上选择了关节2的电机和谐波减速器,设计了关节模块的测控电路,研制了单关节部件样机并进行了重复性实验。其中单方向测量数据表明,为保证较小的测量重复性误差,关节在运动时应尽量避免速度或加速度突变的运动形式;双方向测量的数据表明,当控制电机运动速率小于1.53rad/s时,测头因回弹产生误触发信号的概率较小,此时最大误差数据为±2.11″。上述实验也验证了模块化关节设计方案的可行性,为后续自驱动关节臂坐标测量机整机研制提供了理论和实验依据。

Design of modular articulation in self-driven AACMM

A large subjective error and low measurement efficiency occurs as a result of manual movement and measurement in a traditional Articulated Arm Coordinate Measuring Machine (AACMM) to solve the problem of worse path planning, In this case, it is difficult to adapt the system to the new requirements of online automatic measuring systems. As such, the concept of a self-driven AACMM is proposed which includes a brushless motor and a harmonic reducer, and demonstrates precise shafting in its articulation. A structure for the modular articulation and the torsion estimating model is also proposed. A prototype and experimental device of the Joint2 with a measurement and control circuit, motor and harmonic reducer were built to evaluate the performance and facilitate a series of repeatability experiments. A prototype with a single joint component was developed and repeatability experiments were performed. The single direction measurement data show that to ensure a small repeatability error, the joints should avoid drastic changes in velocity or acceleration when in motion. The data from the measurement of both sides show that when the motor speed of the control machine is less than 1.53 rad/s, the probability that the probe will produce a false trigger signal is small, and the repeatability error is ±2.11". The experiment also verifies the feasibility of the modular articulation design scheme. These research findings provide a theoretical and experimental basis for studying completely self-driven AACMM.