Design, modelling and validation of a novel extra slender continuum robot for in-situ inspection and repair in aeroengine

In-situ aeroengine maintenance works are highly beneficial as it can significantly reduce the current cycle which is extensive and costly due to disassembly requirement of engines from aircraft. However, navigating in/out via inspection ports performing multi-axis movements with end-effectors in constrained environments (e.g. combustion chamber) fairly challenging. A novel extra-slender (diameter-to-length ratio < 0.02) dual-stage continuum robot (16 degree-of-freedom) proposed navigate out confined perform required configuration shapes for repair operations. Firstly, design presents several innovative mechatronic solutions: (i) tendon-driven structure bevelled disks provide selective stiffness carrying high payloads; (ii) various rigid-compliant combined joints enable different flexibility each stage; (iii) three commanding cables 2-DoF section minimise number actuators precise actuation. Secondly, a segment-scaled piecewise-constant-curvature-theory based kinematic model Kirchhoff-elastic-rod-theory static established by considering applied forces/moments (friction, actuation, gravity external load), where friction coefficient modelled function bending angle. Finally, experiments were carried validate modelling evaluate capabilities predefined shape stiffness.