具控制打擊後球體軌跡能力之擊球機器人設計與實現

Abstract

本研究使用雙眼相機偵測投球者投出的球，搭配自行設計的四軸機械手臂，可將球擊至所指定的目標點。在雙眼相機的影像處理上，可對高速飛行下的球體進行追蹤，並且利用切換影像處理區域以及程式的平行化運算，來提高影像處理速度。透過相機校正以及立體視覺，可將球體位置從二維影像平面轉換到三維空間，並且使用拋物線方程式來估測球體飛行時的軌跡。在機械手臂方面，推導出機械手臂動態模型，使用參數估測法求得手臂未知參數，並設計控制器來控制手臂，使手臂可以追隨所設定之軌跡位置以及速度，在擊球時間點到達擊球點以及達到所需的擊球速度。建立球與拍子之間的碰撞模型，加入拍子速度於模型中，對於擊球後球的飛行軌跡增加一項可控制項，並且利用機構限制來算出擊球時間點以及擊球點，透過RS232將擊球資訊傳輸至高效能數位訊號處理器來即時規劃軌跡與擊球，使擊球後球的飛行軌跡通過所設定的目標點，達成擊球至指定目標的目的。

This thesis is dedicated to the design and implementation of a four-joint robot in order to bat a flying ball to a designated position. The ball-batting robot uses a stereo camera and image processing techniques to identify the ball in a cluttered environment and to predict its flying trajectory in the 3D space. Then a collision model is established to characterize the relation between the velocities of the ball and the racket installed at the end of the robot. Based on the collision model, the contact point and contact time are determined, and the trajectory of the batted ball can be controlled by adjusting the orientation and velocity of the racket. Through RS232 communication, the predicted contact point and the desired velocity of the racket are sent from the image processing unit (a personal computer) to the motion controller (a high-performance DSP processor) of the robot for path planning. Then the robot is commanded to the predicted contact point on time with desired velocity and orientation. Therefore the batted ball can reach the target position as desired.