Snake-arm robots to conduct CANDU pipe inspection

Feb. 13, 2009 - PRLog -- Ontario Power Generation (OPG) has awarded a contract to OC Robotics to design and build a snake-arm robot mounted on a mobile vehicle that will be used to inspect complex pipework and structures within CANDU reactors.

The snake-arm will be 2m (7’) in length and will have a rectangular cross-section measuring 25mm (1") in width and 50mm (2") in height. In the first instance the snake-arm will be equipped with tip cameras for pipe inspection.

This is a breakthrough contract for OC Robotics as this is the first time they have been the prime contractor to a nuclear utilities company. OC Robotics won the contract by demonstrating previous nuclear experience and the ability to meet the stringent quality requirements including ISO9001. This contract is a huge achievement considering the company currently employs only 17 people and was bidding against some of the largest companies in the world.

OC Robotics was founded in 1997 and raised venture capital in 2001. Since then the company has grown from a 2-person start-up in a garage to a 17-strong company in 10,000 sq ft premises. OC Robotics has worked with some of the largest companies in the world across aerospace, defence, nuclear and other industries building snake-arm robots for a wide range of applications.

OC Robotics completed its first commercial nuclear contract in 2004. Working with Uddcomb AB, OC Robotics supplied two types of robot (five in total) to Ringhals AB in Sweden to complete an urgent pipe replacement in an extremely awkward area below one of their reactors.

Snake-arm robots are flexible robotic arms which have many joints so they can “follow their nose” into confined spaces. OC Robotics is the only commercial manufacturer of snake-arm robots in the world.

CANDU (CANada Deuterium Uranium) reactors are Canadian invented nuclear reactors originally developed in the 1950s and 1960s. There are currently 19 operational reactors in Canada and 23 in the rest of the world. OPG owns and runs 10 of these reactors and leases 2 others.

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Background information

Over the last decade OC Robotics has found that there are many similarities between surgery and inspection and repair of high value equipment. In the past, surgery required large incisions with all the associated risks of infection and complications. Nowadays minimally invasive, keyhole surgery has reduced patient risk and hospital stays. And, as a prescient for the next paradigm shift, surgeons have already performed ‘scarless surgery’ using natural orifices to gain access to the abdomen.
As the world enters a global recession life extension projects for high value installations, such as nuclear reactors, submarines, subsea structures, are even more strategically important. Extending the life of an aging $1bn nuclear asset is necessary to ensure continuity of supply before new build takes up the strain. But that same asset may have already reached the end of its original design life and may not have been designed with maintenance in mind. Furthermore, the open-heart surgery option may be no option at all due to the costs involved and the risks of failure.
OC Robotics has been working to provide a solution to these challenges. We are working with customers around the world to develop snake-arm robots that can conduct minimally invasive maintenance and repair through small (typically pre-existing) access holes.

What are snake-arm robots?

The name ‘snake-arm robot’ gives a good description of how these robots look and move. They are slender, flexible manipulators which can follow a path into a confined space. A snake-arm robot is an extremely versatile robotic arm that can carry cameras and tools into environments which cannot otherwise be accessed.
The structure of a snake-arm robot is similar to a human spine in that it is comprised of a number of vertebrae. It is a tendon-driven arm with wires terminating at various points along the length of the arm allowing the joints to be controlled independently. (Please see the information and diagram on our website at www.ocrobotics.com/technology for more details.)
A motor is used to control the length of each wire independently. The control software calculates the necessary lengths of all the wires to produce the desired shape. While the operator uses a joystick to drive the tip, the computer does the maths to make the arm follow. This tip-following capability enables a snake-arm robot to avoid obstacles and “follow its nose” into complex structures. The operator can also control the arm in tool or world space, whilst continuing to avoid obstacles.
All OC Robotics snake-arm robots have a hollow bore that runs the length of the arm. This means that all services can be carried within the arm so that the external surface is smooth and continuous. It also means that the arm can be used as a steerable hose-pipe or a vacuum cleaner!
The technology is very scalable and OC Robotics has designed arms to be large and durable as well as small and compliant. Snake-arm robots can combine a significant payload with precise positioning and still snake into confined spaces.

History of OC Robotics

The company was founded in 1997 by Dr Rob Buckingham and Andrew Graham and began in Rob’s attic. The company began as a consultancy designing complex mechanisms for customers such as HP and Rolls Royce. In 2001 Rob and Andy decided to revisit some research they had done while at Bristol University which involved many jointed robot arms. They raised venture capital funding and expanded the company into Rob’s garage. Over the next few years the company won key contracts with the UK MOD, the US DOD, Ringhals AB (a Swedish nuclear operator), British Nuclear Group and Airbus, and out-grew the garage.
OC Robotics now has 17 people focused on the core areas of business development, design and software. The company is based in 10,000 sq ft of workshop and office space in Filton, Bristol, UK.

Ringhals nuclear repair

OC Robotics completed its first commercial nuclear contract in the summer of 2004. Two types of robot (five in total) were supplied to Ringhals AB to complete an urgent pipe replacement in an extremely awkward area below one of their reactors.  
Before the operation could be performed on the real environment, there was extensive training on a custom-built mock-up.  After thoroughly practising the whole procedure, the team, led by Uddcomb Engineering AB (now part of Areva), conducted a trial installation and operation within reactor containment as part of the acceptance tests.  Replacing the leaking section of pipe involved more than 30 distinct procedures with the majority being conducted by the robots working cooperatively.
The more flexible snake-arm was used to get the ideal camera location to monitor the process whilst the other snake-arm was used to deliver the processing tools and fixtures, remove the old pipe, introduce the new pipe and conduct tasks such as welding and inspection.
In August 2004 a single pipe repair was successfully completed and, a month later the generic solution, based on the snake-arm robots and able to repair any of the other 156 similar pipes, successfully completed the Factory Acceptance Tests.

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About OC Robotics:
OC Robotics helps companies reach the unreachable. Snake-arm robots are flexible robotic arms that don't have 'elbows', so they can follow their nose into confined spaces.
OC Robotics is the only commercial manufacturer of snake-arm robots in the world.