Page 535 - The ROV Manual - A User Guide for Remotely Operated Vehicles 2nd edition

532 CHAPTER 19 Manipulators
19.7.6 Tooling stabilization techniques
With a human analogue to a subsea task, a carpenter or mechanic performing precise tasks (such as cutting a board or turning a nut) must first steady the board or bolt with one hand and perform the task with the other. This allows the manipulator with end effector (i.e., hand with saw or wrench/ spanner) to steady the work item with reference to the tool (board or bolt).
The standard further provides recommendations for access to the work item along with methods of steadying the tool (locking the tool frame with the work item frame). The following stabilization methods are used:
1. Attach a flat horizontal platform to the work item (just adjacent to the interface) for the ROV to park and then steady itself onto the platform by downward thrusting onto the platform.
2. Provide a horizontal or vertical bar on the face of the interface for the ROV to grasp with a limited function grabber so that the other (more dexterous) manipulator can work while steadied by the gripper.
3. Provide docking points (such as Figure 19.27) directly on the interface.
4. Design the interface with relatively flat, smooth surfaces for using suction cup (“sticky foot”)
attachments, such as those depicted in Figure 20.9.
19.7.7 Standards summary
To summarize the discussion on tooling interface configurations covered within the standard, remote tooling is delivered to the work site as either integrated into the ROV or as a separate ROT in either manipulator or TDU mode. While specific differences are discussed, manufacturers of both subsea production components, as well as ROV tooling, can use this standard to design tooling interfaces compatible with the standard production system. The process from inception to final design is charted in Figure 19.30.
Within the ISO 13628 (sections other than Part 8), specific subsea production system design guidelines are discussed toward a (hopefully) seamlessly standardized ROV-friendly system.
19.7.8 Subsea facility and tooling design
Per the ISO 13628 standard, some of the facility and vehicle design philosophies that should be
considered include (with section number referenced from the standard):
• ROV access to the work site (Section 4.4.8)
• Intervention system selection considering FMECA (Section 6.2.1)
• ROV load constraints while in operational mode (Section 6.2.6)
• “Fail-to-free” TDU connections (Section 4.4.3)
• Minimization of damage potential and other facility protective measures (Section 4.4.4)
• Structural design so as to minimize the potential for tether snagging (Section 4.4.6)
• Provide a positive means of stabilizing the work platform (besides thrusters) (Section 4.4.7)
• Proper identification markings (both description and function) for all components
(Section 6.4.1)
• Height of interfaces above bottom (Section 6.5.5)
• Load reaction imposed on the interface (as opposed to on the vehicle) (Section 4.4.5)