There is a substantial financial incentive for in-situ repair of industrial assets. However, the need for highly trained mechanics to travel to the location of a repair often results in inconveniently long downtimes. The emergence of robots capable of replicating human interventions on industrial equipment can be coupled with remote control strategies to reduce the response time from several days to a few hours. This work outlines the design and remote control strategy for a novel robotic system to carry out repairs on aeroengine compressors in-situ via the internet. A high-level control computer serves as an interface with the skilled operator. A low-level controller receives instruction packets from the high-level controller via the internet and uses them to determine the necessary movements to carry out a machining operation. The robot, comprising a combination of rotary, prismatic and flexible (continuum) joints, was designed to replicate the degree of freedom of hand-held tools. Sensors and encoders on the robot enable the low-level controller to independently detect faults and stop all motion despite the high latency of internet communications. The remote control system was tested by machining stress relief features on eleven compressor blades with a median RMS error of 0.064 mm between the desired and measured blends. A successful demonstration on a production aeroengine shows the capability of the system.

No abstract

Automation of inspection and repair tasks on complex installations is gaining attention from industries with high-value assets such as aerospace, nuclear and marine. This paper reports on a five degrees of freedom robotic system capable of performing accurate and repeatable repair procedures through a narrow inspection port, which minimizes the cost and downtime associated with unscheduled maintenance. Careful study of the target working volume and repair process informed the design of a robotic probe capable of replicating the operation. Kinematic analysis of the robot's flexible, prismatic and rotary joints was used to define accurate machining paths in 3D space, and the results were verified using an optical motion capture system (accuracy of 0.25 mm). After comprehensive verifications of the constitutive elements, the robotic system was successfully demonstrated for repair of a high-pressure compressor aerofoil in a gas turbine. The results not only proves the ability of the system to address such difficult repair scenarios but also highlights a domain of opportunities in developing specialist robotics for repair of high-value assets, which is a subject to growing global demand.