A UK-led, EU-funded research project has significantly advanced robotics technology, developing a robotic system for in-situ repair and maintenance that makes work in hazardous environments easier and safer which could be on the market in three to five years.

Photo of a crane in an offshore drilling platform

The MiRoR project can put two major innovations to its name: a novel walking hexapod robot and a flexible robot arm, also known as a ‘continuum robot’. The team of researchers built both elements with specific areas of application in mind: the system is uniquely suited to maintenance and repair tasks, including machining, in tight, difficult or dangerous-to-access spaces in power plants, construction and aero-engines, or on offshore platforms.

However, thanks to its autonomy, versatility and manoeuvrability, the MiRoR robot is not limited to these fields. For instance, the medical sector has already shown interest, seeing its potential for minimally invasive surgery.

The team behind the robot was coordinated by Dragos Axinte from the University of Nottingham and including academia/research organisations (IK4-Tekniker, IPA Fraunhofer and ETH Zurich) as well as experts from the aerospace, civil engineering and energy industries (Rolls-Royce and Acciona).

Walk and snake

The hexapod robot – which gets its name from its six legs and was developed by the Spanish technological innovation centre IK4-Tekniker in collaboration with University of Nottingham – consists of a flat platform with the legs attached to it. Each leg boasts a special articulation system, which means it can be steered individually in any direction.

While the researchers had already developed the initial concept for the hexapod before the project started, early versions had to be placed manually. The intelligent control developed by IPA allowed them to make the robot more autonomous; equipped with a camera and sensors to help detect defects and facilitate direction, it can now either be guided by an operator or navigate itself to the location where maintenance or repair works are needed.

“There is a sensor attached to the front of the robot that works like a scanner and can detect objects in its surroundings, so that it can avoid obstacles and find the best way to the target ,” explained Aitor Olarra from Tekniker, who was tasked with the design of the hexapod robot.

Controlling stiffness

Mounted on the walking hexapod is the continuum arm robot that has been developed by the researchers from the University of Nottingham. With an outer minimum diameter of 15 mm and 1200 mm in length, its snake-like flexibility lets the robot bend and reach inside confined spaces such as a jet engine, for example. But its outstanding feature is that the arm has two states of stiffness.

Xin Dong of the University of Nottingham commented:

“Imagine the compressor is damaged. Conventional robots cannot do the proper repairs because they require the robot to have sufficient degrees of freedom to reach the location by passing through the ‘compressor forest’ and also very good stiffness when repairing,”

He and his colleagues used twin-pivot compliant joints, which help avoid having to twist the arm when bending into convoluted shapes. Each link of the arm can be articulated individually. A through-hole inside the arm allows for a selection of machining tools to be passed through to the tip, so that – once in place – the arm can be made completely stiff and inflexible with the help of thermal plastics to carry out whatever repair task is required.

Following successful system testing in a mock-up environment as well as under real-world conditions at project partner Rolls-Royce’s aerospace branch, Dong is hopeful that the MiRoR system will soon be ready for application in the real world. He predicts that the first robots may be employed for in-situ repair of aircraft in large airports within the next three to five years.

The UK acted as coordinator on the €4.98 million MiRoR project, partnering with researchers from Spain, Switzerland, Romania and Germany.