Posture measurement and coordinated control of twin hoisting-girder transporters based on hybrid network and RTK-GPS

In this paper, a typical application of multimobile robots, i.e., twin hoisting-girder transporters cooperating to transport a giant concrete girder, is studied. An overall solution based on the hybrid network communication framework is presented and the key issues, such as the accurate posture estimation and coordinated control of the two independent transporters forming a team, are researched. In order to obtain the relative distance and orientation angle between two transporters while traveling, a measurement data fusion method using real-time kinematic global positioning system for kinematic locating and in-vehicle speed sensors for speed measuring is proposed. Furthermore, a distributed master-slave coordinated control strategy based on the hybrid network framework is proposed to meet the reliability and accuracy requirements. The application results show that the deviations of the relative distance and the orientation of two transporters during working are not more than 0.1 m and 0.2°, respectively, and it can meet the requirements of the technological specifications.