In-situ aeroengine maintenance works (e.g. inspection, repair) are highly beneficial as it can significantly reduce currently accepted maintenance cycle which is extensive and costly due to the need to remove engines from the wing of an aircraft. However, feeding in/out via inspection ports and performing a multi-axis movement of an end-effector in a very constrained environment such as aeroengine combustion chamber is a fairly challenging task. This paper presents the design and development of a highly slender (i.e., low diameterto-length ratio) dual-structure continuum robot with 16 degrees of freedom (DoFs) to provide the feeding motion needed to navigate into confined environments and then perform a required configuration shape for further repair operation. This continuum robot is a compact system and presents a set of innovative mechatronic solutions such as: (i) two-stage tendondriven structure with bevelled disk design to perform required configuration shape and to provide selective stiffness for the ability of taking high payloads; (ii) various compliant joints to enable different flexibility requirement in each stage; (iii) three commanding cables for each 2-DoF section to minimise the number of actuators with a precise actuation. To be able to achieve the desired configuration shape, a kinematic model has been established and the configuration-cable kinematics has been implemented. Finally, the continuum robot has been built and tested for performing the predefined configuration shape.

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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.