This letter proposes a mobile quad-arm robot: ARMS that unifies wheel-legged tripedal mobility, wheeled mobility, and quad-arm manipulation. The four arms have different mechanics and are designed to be general-purpose arms to enable the wheel-legged hybrid mobilities and manipulation. The three-degree-of-freedom (DOF) front arm has an active wheel, which is used for wheel-legged tripedal walking and wheel driving with passive wheels attached to the torso. The three-DOF rear arms are series elastic arms, which are used for wheel-legged tripedal walking, object grasping, and manipulation. The two-DOF upper arm is used for manipulation only; its position and orientation are determined by coordinating all arms. Each motor is controlled by an angle controller and trajectory modification with angle, angular velocity, angular acceleration, and torque constraints. ARMS was experimentally validated on the basis of the following four tasks: wheel-legged walking, wheel-driving, wheel-driving with grasping, and carrying a bag.

翻译：本文提出一种移动四臂机器人ARMS，该机器人融合了轮腿三足移动、轮式移动与四臂操控功能。四个机械臂具有不同机械结构，被设计为通用型机械臂以实现轮腿混合移动与操控。三自由度前臂装有主动轮，用于轮腿三足行走及与躯干被动轮协同的轮式驱动；三自由度后臂为串联弹性臂，用于轮腿三足行走、物体抓取与操控；二自由度上臂仅用于操控，其位置与姿态通过各臂协同确定。每个电机由角度控制器控制，并在角度、角速度、角加速度及扭矩约束下进行轨迹修正。基于轮腿行走、轮式驱动、抓取状态下的轮式驱动及背包搬运四项任务，对ARMS开展了实验验证。