Communication System of Realtime Two-Dimensional Position Data with Scanning Laser Beam

Most construction work; indoors and outdoors, involves movements. In the development of robots to be used at the construction site, one of their intended functions is movement control, positioning in particular. In the field of industrial robots as well, recent developments incorporate movement functions represented by AGV (Automatically guided vehicle), in addition to such fundamental functions as arms and manipulators. However, these movement functions usually employ optical or electromagnetic navigation and the area of movement is extremely limited. Whereas in the case of robots performing construction jobs, the required area of movement is expanded two- or even three-dimensionally to fifty meters or so. It is therefore considerably difficult to control the movement of such robots that travel along the predetermined travelling route. The use of positioning systems utilizing GPS was proposed in many case histories of robot development, some of which report their practical use. However, fluctuations in the systems' positioning accuracy are still heavy, making their application to fast-travelling robots difficult. Moreover, the systems' mechanical instability may cause run-away of robots. Another problem is that such systems are usually bulky and expensive, restricting their application and widespread use. A few other problems still remain unsolved. In view of the situation, the authors developed a surveying system that allows real-time positioning of a moving target with high accuracy by scanning laser beams at a high velocity from two known coordinate points. Positioning data is transmitted and displayed to the target. This paper presents an overview of the "Real-time two-dimensional positioning data transmission system" developed by the authors along with case histories of its application.