The ARM (Automated Remote Manipulation) Project has developed a new subsea systems for the cleaning and inspection of nodal welds. It consists of an advanced robotic manipulator mounted on an extend/roll mechanism. This is part of a special toolskid carried by a standard workclass ROV. The manipulator was developed specially for inspection by Slingsby Engineering Limited. It is controlled by a unique, PC-based robot system developed by Technical Software Consultants Limited. This provides a full 3D manual, semi-automatic and robotic control of the manipulator (with collision detection). The ARM systems will be completed, and undergo testing, during the summer and autumn of 1995. This will culminate in full offshore trials during the spring of 1996.
The ARM 1 Project ended in September 1994 with the build of the new underwater manipulator and computer supervisory control system. Work continues in the ARM 2 Project to complete an entire inspection system consisting of the manipulator, an attachment systems, a compliant tracking system and an array based subsea NDT sensor. As before, this phase is being conducted by Slingsby Engineering Ltd (SEL) and Technical Software Consultants Limited (TSC) with sponsorship from Mobil North Sea Ltd (MNSL) and the Offshore Supplier Office (OSO).
The aim of the ARM Projects has been to produce a wholly new kind of sub-sea inspection systems, capable of doing advanced cleaning and inspection tasks in areas beyond the reach of divers. It will also be able to work at the same operating depths as divers but at lower cost and with greater safety and reliability. In particular, it was a requirement to be able to clean and inspect complex node welds on sub-sea structures, these nodes generally consisting of a number of intersecting tubulars and the welds therefore being of a very complex shape. Because of the difficulties of accessing these welds, a completely new systems has to be designed ‘from the grounds up’. Under the sponsorship of Mobil and OSO, a cleaning and inspection system was planned which would incorporate a completely new underwater manipulator-to be designed, built and tested by Slingsby Engineering Limited (SEL)- and an advanced computer control system, designed, built and programmed by Technical Software Consultants Limited (TSC) in conjunction with University College London (UCL). The first build manipulator and control system were completed during ARM 1.
The ARM supervisory controller comprises a fast PC surface graphics control unit linked via the Remotely Operated Vehicle (ROV) umbilical to a subsea arm controller. This provides full control of the manipulator, including manual master-slave tele-manipulation and fully automated, robotic task execution. A 3D video representation of the ROV, manipulator and work site is presented to the operator using solid shaded colour graphics, and can be used to monitor the arm whilst planning or executing tasks. The viewpoint can be modified to aid visualization, and secondary windows used to display plan and elevation views of the arm and its work area. Also the arm can be viewed as if from an ROV mounted camera to give a close up