Rugged Encoders for Subsea Robotics

The Challenge

In subsea robotics, remotely operated underwater vehicles (ROVs) are unmanned underwater vehicles (UUVs) controlled by a crew above the water. ROVs have become an indispensable tool to the offshore oil and gas sector, for use in intervention tasks in deep water environments. Work class (class Ill) type ROVs are large systems, sometimes the size and weight of a small car, and can feature multiple manipulators, used to perform tasks such as removing debris and operating valves in deep water environments.

While many manipulators are hydraulically actuated for high payload requirements, a rise in BLDC actuated manipulators are being sought for advanced tasks requiring high reliability or fine control of gripper position and contact force sensing. These BLDC actuated manipulators are oil filled systems, and have typically depended on analog resolvers, which offer reliable position sensing when subject to high pressures at depth. Resolvers however, are typically bulky devices, requiring an external AC excitation signal as well as additional signal processing hardware to convert the analog output.

The Solution

The Celera Motion IncOder™ Series are the next generation of resolver, providing the robust benefits of an analog resolver with a high resolution digital position output. Featuring a DC supply input, and numerous digital output options as standard, the IncOder feedback sensor can easily be integrated into a closed loop manipulator control system. All IncOder options can function when submerged in oil, and by selecting extended option “V” IncOder is potted under vacuum to significantly reduce internal voids in the potting compound structure, for use at high pressures. Each product features a robust low corrosion anodized aluminium alloy housing, designed with a compact, large bore, low profile form factor.

The Benefit

With high resolution outputs up to 22-bits, the IncOder series offers more precise torque sensing and control of each individual robotic joint in the ROV manipulators, enabling more demanding manipulator functions. IncOder features a robust design with the ability to extend performance for operation at high pressures, which is suited for use in ROV manipulators. The low-profile form factor enables a more compact manipulator design reducing the impact of dynamic coupling between the arm and the vehicle.

Specifications