Trajectory control of omni-directional mobile robot with considering shift of center of gravity and nonlinear friction which is affected by direction of movement

对全向轮式移动机器人进行了机理分析和性能改进研究。在这里，全向轮具有特殊的机构以实现全向运动。研究结果表明：1)建立了受运动方向影响的全向轮非线性摩擦模型。这一结果使全向轮式移动机器人的位置或速度的精确控制成为可能。2)提出了合适的重心动态位移模型。该模型具有很强的非线性。为了补偿这种非线性，提出了一种新的控制策略。通过全向轮式移动机器人及机械手系统的仿真和实验，验证了该控制策略的有效性。

Mechanism analysis and performance improvement of an omni-directional wheel mobile robot is purpose of this research. Here, an omni-directional wheel has special mechanism in order to achieve omni-directional movement. The results of this project are as follows: 1)Appropriate model of nonlinear friction of omni-directional wheel that is affected by direction of movement has been proposed. This result makes it possible to control position or velocity of an omni-directional wheel mobile robot accurately. 2)Appropriate model of dynamic shift of center of gravity has been proposed. Such model has strong nonlinearity. In order to compensate such nonlinearity, a novel control strategy has been proposed. The validity of the new control strategy has been investigated by simulations and experiments using an omni-directional wheel mobile robot and manipulator system.