- 期刊
機械臂即時軌跡產生－以Delta Robot為例
Real Time Trajectory Generation for Delta Robot
摘要
本文開發一種即時軌跡產生演算法，能讓機械手臂動態狀態下，隨時接收新的目標命令，即時產生具有連續加速度的三階多項式運動軌跡。演算法可用於配備3D，視覺感測器的智慧機械人系統，上層控制器偵測到外部環境變化，而可立刻改變路徑，即時產生新軌跡。軌跡產生適用於任意初始速度與加速度狀態，並且可指定運動的最大速度，加速度與Jerk值，但目標狀態是靜止。運用本產生器於多自由度機械臂的運動控制時，可使各軸軌跡同時抵達目標點。新創的軌跡演算法，軌跡更新可在一個控制周期完成，達到即時反應。本演算法在自製的Delta機械臂，以虛擬模型模擬及實驗驗證其性能。透過model-based design，以電腦模型完成：開發演算法，模擬驗證，產生控制軟體和實驗測試的工作階段。
並列摘要
This article presents a real time motion-profile generation algorithm, which can instantly provide a profile based on the current velocity and acceleration with new destination target position. The motion profile has continuous acceleration with constant jerk. Dynamic motion profile generation is important to intelligent robots equipped with multiple vision or depth sensors to react instantaneously to external events under dynamic condition. The proposed algorithm adopts a third-order polynomial function in displacement to provide continuous acceleration under constraints of maximum velocity and maximum acceleration to generate a new profile at arbitrary instant during motion. The algorithm includes a motion-synchronization function to schedule profiles for all joints to arrive the target angles at the same time. Conceptual design and the aftermentioned methods are implemented in a self-made Delta robot arm. We take a model-base approach in the development stages. The algorithm is developed and simulated with 3D robot CAD model. Later, simulation-proven algorithm was combined with EtherCAT communication interface to control this EtherCAT-controlled robot arm. From the simulation and experiment results, the algorithm can react to suddenly changed target position command, and the total update time for the trajectory is less than one cycle time at the worst case.