【摘要】 提出一种名为MultiCal的新型接触式三维测量装置，可用于机械臂的现场标定和在线精度测量，具有使用方便、成本低（低于5000美元）、性能可靠等优点。该设备可灵活地设置在机械臂的工作环境中进行微米级精度三维测量。在标定过程中，通过一个三维位移测量装置，让机械臂的工具中心点运动至一个固定点，之后再绕该点旋转运动至不同姿态角并测量各关节角度（单点约束测量）。然后采用一个创新设计的夹具，将三维位移测量装置精确地安装在该夹具的不同工位上，并重复上述测量过程，从而实现多点约束测量。夹具上不同工位的相对位置在标定前已被精确测量，并作为标定的先验信息，以提高标定的精度与鲁棒性。理论分析表明，在相同水平的测量误差下，MultiCal的理论标定精度与传统的非接触式三维或六维测量设备（如激光跟踪器）相比降低10%—20%。而在StaubliTX90机械臂上进行的实际标定实验结果表明，MultiCal实际标定精度仅比带激光扫描仪的测量臂低7%—14%，时间效率比六维双目视觉测量系统低21%—30%，标定后的机械臂的最大和平均绝对定位误差分别为0.831mm和0.339mm。更多还原

【Abstract】 A novel in-contact three-dimensional(3D) measuring device, called MultiCal, is proposed as a convenient,low-cost(less than US$5000), and robust facility for onsite kinematic calibration and online measurement of robot manipulator accuracy. The device has μm-level accuracy and can be easily embedded in robot cells. During the calibration procedure, the robot manipulator first moves automatically to multiple end-effector orientations with its tool center point(TCP) constrained on a fixed point by a 3D displacement measuring device(single point constraint), and the corresponding joint angles are recorded. Then, the measuring device is precisely mounted at different positions using a well-designed fixture, and the above measurement process is repeated to implement a multi-point constraint. The relative mounting positions are accurately measured and used as prior information to improve calibration accuracy and robustness. The results of theoretical analysis indicate that MultiCal reduces calibration accuracy by 10% to 20% in contrast to traditional non-contact 3D or six-dimensional(6D) measuring devices(such as laser trackers) when subject to the same level of artificial measurement noise. The results of a calibration experiment conducted on a Staubli TX90 robot show that MultiCal has only 7% to 14% lower calibration accuracy compared to a measuring arm with a laser scanner, and 21% to 30% lower time efficiency compared to a 6D binocular vision measuring system, yielding maximum and mean absolute position errors of 0.831 mm and 0.339 mm,respectively.更多还原