The article developed a path planning method for mobile robots moving to the target position on the unknown environment, and uses the dynamic programming algorithm to solve the minimum displacement techniques. The mobile robot has the shape of cylinder and its diameter, height and weight is 8cm, 15cm and 1.5kg. The controller of the mobile robot is MCS-51 microchip. The mobile robot contains a controller module (including DC motor driver), an obstacle detection module, a voice module, a wireless RF module, an encoder module, and a compass module. Mobile robots can modify the error of the orientation using the compass module, and use encoder module to calculate displacement. We design the grid platform to implement the proposed method using the mobile robot. In the experimental results, the supervised computer controlled the mobile robot moving to the target position on the unknown environment, and receives the pulse numbers from the mobile robots via wireless RF interface. The supervised computer fined out the minimum displacement, and compared to the previous trajectories, and controlled the mobile robot moving to the start position according to the minimum displacement.