Aerospace production volumes have increased over time and robotic solutions have been progressively introduced in the aeronautic assembly lines to achieve high-quality standards, high production rates, flexibility and cost reduction. Robotic workcells are sometimes characterized by robots mounted on slides to increase the robot workspace. The slide introduces an additional degree of freedom, making the system kinematically redundant, but this feature is rarely used to enhance performances. The paper proposes a new concept in trajectory planning, that exploits the redundancy to satisfy additional requirements. A dynamic programming technique is adopted, which computes optimized trajectories, minimizing or maximizing the performance indices of interest. The use case is defined on the LABOR (Lean robotized AssemBly and cOntrol of composite aeRostructures) project which adopts two cooperating six-axis robots mounted on linear axes to perform assembly operations on fuselage panels. Considering the needs of this workcell, unnecessary robot movements are minimized to increase safety, the mechanical stiffness is maximized to increase stability during the drilling operations, collisions are avoided, while joint limits and the available planning time are respected. Experiments are performed in a simulation environment, where the optimal trajectories are executed, highlighting the resulting performances and improvements with respect to non-optimized solutions.
翻译:航空航天生产量随着时间推移而增加,机器人生产量逐渐增加,在航空组装线中逐渐引入了机器人解决方案,以达到高质量标准、高生产率、灵活性和降低成本;机器人工作细胞有时以安装在幻灯片上的机器人为特征,以增加机器人的工作空间;幻灯片引入了额外程度的自由,使系统在运动上变得多余,但这一特性很少用于提高性能;本文件提出了轨迹规划的新概念,利用冗余来满足额外要求;采用了动态编程技术,计算出优化轨迹,最大限度地减少或最大限度地提高性能指数;在LABOR项目(Lean机器人化的Assembly和复合机器人结构的Ontrol)上界定了使用情况,该项目采用两种合作型六轴机器人安装在线轴上进行组装操作,提高性能;考虑到该工作室的需要,不必要机器人运动最小化,以提高安全性;采用了机械刻板,以在钻探作业中增加稳定性,避免碰撞,同时避免了联合限制,并按现有规划时间进行升级,在不进行最佳的环境下进行实验。