具軟式夾爪與欠驅動手臂之自主移動機器人設計及自主導航應用

Abstract

本研究旨在開發可搭載於自主移動機器人之欠驅動機械手臂，並設計一具有四隻爪子之夾爪作為手臂之末端致動器。本研究使用之自主移動機器人為四舵輪機構，透過運動學的轉換，使其具備差速運動模式以及全向移動模式，並且具備里程計之回授。此外，自主移動機器人配備光學雷達以及慣性測量單元，並透過人工勢能場實現路徑規劃，使機器人能夠建置地圖並且導航及自主避障。經驗證，導航過程中最高時速可達每秒0.67公尺。此外，本研究開發兩種不同的欠驅動手臂，其均為三節串列式連桿機構，且透過拉線驅動使手臂運作，分別採用3D列印以及金屬製造。手臂上的每顆關節均配置絕對式磁編碼器，結合諧波減速機可實現高精度之位置控制，並且混合速度控制以及電流控制架構，實現響應快速且穩定的線驅動控制系統，實驗驗證各關節的平均誤差均小於0.2度，可滿足大多應用場合之需求。最後，本研究開發的軟式夾爪採用3D列印製成，並且透過線性軸承以及簡易四連桿機構使夾爪能以拉線方式驅動。各個爪子均為多材料之機構，使夾爪具有更好的物件輪廓順應性，此外，夾爪搭載多個感測器，結合物件辨識模型，可實現物件辨識、電流控制等功能。實驗證實透過物件辨識模型，夾爪可分辨不同種類的水果，並及時調整爪力進行物件夾取任務。

This study focuses on developing an underactuated manipulator mounted on an autonomous mobile robot (AMR) with a four-fingered gripper as its end effector. The AMR utilizes a four-steering-wheel mechanism to support both differential-drive and omnidirectional motion, providing odometer feedback. It is equipped with a 2D LiDAR and an inertial measurement unit (IMU), utilizing an artificial potential field approach for path planning, navigation, and obstacle avoidance. The robot achieved a maximum navigation speed of 0.67 m/s. Two versions of the underactuated manipulator were designed, consisting of a three-link serial-chain mechanism driven by cables: one made from 3D printing and the other from metal. Each joint features an absolute magnetic encoder and a harmonic reducer for high-precision control, maintaining an average tracking error below 0.2°. A soft, four-fingered gripper was developed using 3D printing and a four-bar linkage for cable-driven actuation. Each finger is designed for improved contour compliance and includes sensors for real-time object detection and adaptive force control. Experimental results confirm the gripper can distinguish various types of fruit and adjust its grasp accordingly.