In this paper, a new kind of omnidirectional wheelchair typed robot is developed. The robot not only can accomplish the walking support or walking rehabilitation as an aged person or a disabled person is walking, but also can realize power assistance for a caregiver when he/she is pushing the robot to move. The basic structure of the robot is described and the principle of omnidirectional movement of the robot is presented. Further an admittance based human-machine interaction controller is introduced for power assistance. Moreover, an approach of the power assistance on a slope with speed compensation is proposed, and the experimental verification the availability of the approach.