Alternate location method of a robot team in unknown environment

The alternate location method of a robot team is proposed. Three of the robots are kept still as beacon robots, not always the same ones, while the others are regarded as mobile robots. The mobile robots alternatively measure the distance between one of them and three beacon robots with ultrasonic measurement module. The distance data are combined with its dead-reckoning information using iterated extended Kalman filter (1EKF) to realize the optimal estimate of its position. According to the condition the future beacon robots' positions should be desired ones, the target function and the nonlinear constrain equations are set up which are used by nonlinear optimization algorithm to estimate the position of the future beacon robots. By alternately changing the robots' roles as active beacon, the alternate location in unknown environment can be realized. Process and result of the simulation test are given and the position estimation error is within ± 10 mm, which proves the validity of this method.