We developed an easy-to-operate, omni-directional vehicle including the power assist technology that acts for both the lon-gitudinal and rotational motions of the cart. We had two challenges during the development of this powerassisted cart. The first one was that, due to the relatively long body of the cart, it was difficult to keep the balance between lateral movement and turning movement of the cart when shifting the cart laterally. Therefore we modified the equation for calculating the cart

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... turning speed so that the moment, which was driven by the operating force in the right/left direction, was offset. This way, we could stabilize the balance, resulting in a largely increased operating performance in the lateral direction. The second problem was that, during the one-hand pull-operation, the cart tended to run off its course to the right/left, especially during cornering. To solve this problem, we developed a positional control that detects the amount of lateral deviation by dead reckoning. Do-ing so, we could efficiently reduce the lateral deviation of the cart. We have succeeded in largely improving the operating performance by developing the above control technique.