本研究發展一組以彈性體作為連結之機器蛇,並設計一套最佳避障路徑搜尋法。機器蛇由五節模組化的單體所構成,每個單體擁有兩個步進馬達分別驅動左右輪,單體之間以彈簧或海綿等彈性體作為連結,整條機器蛇由十顆微控制器擔任信號處理、協調、控制與通訊等任務。路徑規劃之目的在於找出最短避障路徑。本研究將障礙物近似簡化為圓形,以起點與終點連線當主軸,首先對主軸上的圓做切線,規劃以切線和圓弧銜接而成的可行路徑。利用簡單的幾何關係比較模式比較路徑長度並界定可能為最短路徑之搜尋範圍。此方法可以縮小搜尋空間,並且大幅降低需實際計算路徑長度之運算量。同時,本研究亦提出視窗法(Windowing)求取機器蛇的容許速度,使得機器蛇各單體動作協調一致,而不致解體。
The study develops a snake-like robot with a flexible body and also presents a novel approach to determine an optimal path for obstacle avoidance. The snake-like robot consists of five modular units. Each unit is driven by two stepper motors in a differential way and connected by springs or sponges. Ten microcontrollers are incorporated into the design of the robot and are primarily used for signal processing, motion coordination, control and communication. The purpose of path planning in the study is to find an optimal way from a starting position to a target point without a collision with obstacles. To simplify the planning process, we describe obstacles approximately by circles. Feasible collision-free paths are simply formed by lines tangent to the circles and arcs on the circles. A length comparison approach based on geometric relationship is developed to examine the length of paths and to reduce the searching space of feasible optimal paths. Consequently, the paths necessary to calculate their length for comparison with others could decrease dramatically. Furthermore, the study also proposes a windowing approach to decide the feasible velocity for the snake-like robot to move in accord from falling apart.