Intelligent Robotic Machining Systems: Integrated Process Planning, Monitoring, and Control

制造业是加拿大现代经济的基石，占加拿大商品出口的68%（3540亿美元）和GDP总量的10%以上（1740亿美元）[GC，2018]。机加工是制造航空航天、汽车、电子、生物医学和能源行业精密金属零件的最广泛使用的操作。目前，加工工艺的优化需要多次迭代，并通过设计，工艺规划，监控和检查步骤进行直接的人工监督。这些迭代增加了最终产品的成本和交付周期，并占用了工程资源。与被称为工业4.0（智能工厂）的新工业范式相一致，我的研究计划的长期目标是开发下一代"智能加工系统"，该系统可以为给定的零件自主生成最佳加工策略，在操作过程中监控自己的过程，在真实的时间内相互沟通，并在线做出正确的决策。我目前的重点是智能机器人加工（RM）系统。由于其灵活性，可重构性和相对较大的工作空间，工业机器人在加工应用中的利用已经在研究人员和制造商中获得了大量的兴趣，特别是在过去的5 - 10年中。然而，已知机器人具有低的结构刚度和差的精度，这阻止了它们在航空航天和汽车工业中的精密加工应用中的广泛使用。我目前的研究旨在通过整合基于物理的金属切削模型，监控系统和主动控制策略来解决这些问题。本申请追求以下两个短期目标：** 1）基于模型的工艺规划和机器人加工操作的监控：* 将对加工机器人的结构动力学进行建模。根据估计的切削力预测机械加工操作期间臂的偏转。工件放置、加工方向和机器人的姿势将被优化以实现最小的偏转。将调整刀具路径以补偿预测的偏转误差。** 2)机器人加工系统中的在线过程校正：* 通过监控伺服关节的控制需求，间接测量切削力。颤振不稳定性将通过分析测量振动的频率内容来检测。进给速度和主轴转速将在出现过度偏转和振动时进行智能在线调整。**一个内部开发的开放式结构的机器人加工系统将用于实施的概念。学员（1名博士，3名硕士，1名SS）将获得先进加工，工业机器人以及过程监控和控制方面的基础知识和独特技能，这些技能在加拿大航空航天和汽车行业中非常受欢迎。

Manufacturing is a cornerstone of Canada's modern economy accounting for 68% ($354 billion) of Canadian merchandise exports and over 10% ($174 billion) of the total GDP [GC, 2018]. Machining is the most widely used operation for manufacturing precision metal parts for the aerospace, automotive, electronics, biomedical, and energy industries. Currently, optimization of machining processes requires numerous iterations and direct human supervision through the design, process planning, monitoring, and inspection steps. These iterations add to the cost and lead times of final products and occupy engineering resources. Aligned with the new industrial paradigm known as Industry 4.0 (Smart Factory), the long-term goal of my research program is to develop next-generation “intelligent machining systems” which can autonomously generate optimal machining strategies for a given part, monitor their own processes during the operation, communicate internally with each other in real time, and make online corrective decisions. My current focus is on intelligent robotic machining (RM) systems. Owing to their flexibility, reconfigurability, and relatively large workspace, utilization of industrial robots for machining applications have gained a significant amount of interest among researchers and manufacturers, particularly over the past 5-10 years. However, robots are known to have low structural stiffness and poor accuracy, which have prevented them from widespread use in precision machining applications in the aerospace and automotive industries. My current research aims at tackling these issues by integrating physics-based metal cutting models, monitoring systems, and active control strategies. The following two short-term objectives are pursued in this application:******1) Model-based process planning and monitoring of robotic machining operations:***The structural dynamics of a machining robot will be modeled. The deflections of the arm during a machining operation will be predicted based on the estimated cutting forces. The workpiece placement, machining direction, and the robot's pose will be optimized for minimal deflections. The toolpath will be adjusted to compensate for the predicted deflection errors.******2) Online process correction in robotic machining systems:***Cutting forces will be measured indirectly by monitoring the control demand of the servo joints. Chatter instability will be detected by analyzing the frequency contents of the measured vibrations. The feedrate and spindle speed will be intelligently adjusted online in the face of excessive deflections and vibrations.******An in-house developed open-architecture robotic machining system will be used for the implementation of the concepts. The trainees (1 PhD, 3 MSc, 1 SS) will gain fundamental knowledge and unique skills in advanced machining, industrial robotics, and process monitoring and control, which are highly sought-after skills particularly in the Canadian aerospace and automotive industries.