Development of the Next Generation Underwater Construction Machinery

摘要

Recently, because of an increase in the number and size of ships, ports must become both larger and deeper. Moreover, short construction periods for development projects are desirable. Owing to these conditions, underwater construction work requires greater mechanisation to ensure high efficiency and guarantee the safety of divers who are working in deep water. For this reason, the underwater backhoe with a diver on the machine to act as the operator was developed. More than 10 backhoes are working at present. However, a remote-controlled underwater backhoe is preferable because operator-assisted underwater backhoes need many divers to work in turn, frequently on deep construction sites and for only short working periods. It is difficult to design the complete man-machine interface the first time. It is planned to construct a remote-controlled backhoe using mainly visual images for control because information for operators is mainly visual by nature. This visual image is to be received from an ordinary underwater TV camera and an underwater ultrasonic camera under development at the Port and Harbour Research Institute (PHRI). The backhoe position will be known and tracked by SBL(Short Base Line) and a GPS (Global Positioning System). The first experiment on this equipment was carried out at the end of 2000. For the next generation of underwater construction machines, several technologies are being researched at PHRI. Measuring the force by the motion of the underwater construction machine by using certain instrumentation and then feeding the results back to the operator is very helpful for the operation. Recently compact 6-axis force feed back system has become available and the fundamental research has been carried. The body angle of the underwater backhoe will not only be shown on the CRT but also move the seat of the operator to the same angles, ie the operator will be able to physically feel the inclination to enable operating to be easier. In near future, tele-existence technology will be more reliable by the introduction of sensor fusion and virtual reality technology. As the result, even in the case of remote-controlled operations, the operator will be able to get the sense that he or she is actually working on the ground.