Absolute kinematic calibration of six-axis serial industrial robots using relative measurements

使用相对测量对六轴串行工业机器人进行绝对运动校准

• 批准号: 451559-2013
• 负责人: Hayes, John
• 金额: $ 1.82万
• 依托单位: Carleton University
• 依托单位国家: 加拿大
• 项目类别: Engage Grants Program
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=540380
• 关键词: Absolute; kinematic; calibration; six; axis

The inherent lack of positioning accuracy in standard, un-calibrated industrial robots is a limiting factor for their use in the automation of manufacturing processes, such as those at Enclosures Direct Inc. (EDI). Robots utilized for manufacturing are generally designed to have excellent repeatability (ability to continually reach the same position and orientation, or pose, defined by a set of joint angles stored in the controller) but are lacking in accuracy (moving to a pose for which the joint angles must be computed by the controller). To overcome the accuracy shortcomings the robots are typically used in a "record and play" mode where poses are manually taught by a technician and repeated for long production runs. When dealing with shorter production runs of customized products, as is the case at EDI where over 3000 different products are offered, it is not viable to manually teach all of the required poses which are instead calculated based on part dimensions or a CAD model. This approach requires the robots to be calibrated in order to meet accuracy requirements. Existing kinematic calibration methods require accurate and precise knowledge of the absolute pose of the robot end effector with respect to the robot base. Achieving this requires an elaborate and expensive measurement system and often requires moving the robot offsite to a calibrated measurement cell. This research project will use recent advances in joint mastering to identify the errors in the six joint angles using relative measurements of tool point position using a novel combination of position sensitive devices and a linear encoder. Once the joint zero values have been identified, the encoder measurements will be used to identify the remaining parameter errors. Observations that the joint angle error is generally larger than the error in the remaining parameters has led to the development of a measurement system that will allow for the separation of the joint angle calibration from the remaining parameters while employing the same experimental data set. The goal of the proposed project is to develop a complete and general system for the kinematic calibration of serial industrial robots.

标准、未校准的工业机器人固有的定位精度缺乏是其在制造流程自动化中使用的限制因素，例如 Enclosures Direct Inc. (EDI) 的自动化流程。用于制造的机器人通常被设计为具有出色的可重复性（能够持续达到相同位置和方向或姿势，由控制器中存储的一组关节角度定义），但缺乏准确性（移动到一个姿势，该姿势是由控制器中存储的）。关节角度必须由控制器计算）。 为了克服准确性缺陷，机器人通常用于“记录和播放”模式，其中由技术人员手动教授姿势并在长时间生产运行中重复。在处理定制产品的较短生产周期时，就像 EDI 提供 3000 多种不同产品的情况一样，手动教授所有所需的姿势是不可行的，而是根据零件尺寸或 CAD 模型计算。 这种方法需要对机器人进行校准以满足精度要求。 现有的运动学校准方法需要准确且精确地了解机器人末端执行器相对于机器人基座的绝对位姿。 实现这一目标需要复杂且昂贵的测量系统，并且通常需要将机器人移至异地校准的测量单元。该研究项目将利用关节掌握方面的最新进展，使用位置敏感设备和线性编码器的新颖组合，通过工具点位置的相对测量来识别六个关节角度的误差。一旦识别出联合零值，编码器测量将用于识别剩余的参数误差。 观察到关节角度误差通常大于其余参数的误差，这导致了测量系统的开发，该系统将允许在采用相同的实验数据集的同时将关节角度校准与其余参数分开。该项目的目标是开发一个完整且通用的系统，用于串行工业机器人的运动校准。