A Miniaturized Tendon-Driven Continuum Robot for Direct Laser Deposition
Luca Raimondi, Matteo Russo, Xin Dong, andy norton, Dragos Axinte
AI summary
Problem
Conventional direct laser deposition setups for aeroengine repair are bulky and require costly engine disassembly, while existing continuum robots lack the precision needed for high-accuracy in-situ manufacturing.
Approach
The authors developed an 8 mm diameter tendon-driven continuum robot with optimized kinematics, integrated actuation, and a protected internal channel for fiber optics, controlled via a portable unit and joystick interface.
Key results
- 0.02 mm standard deviation repeatability on linear paths
- Sub-0.1 mm repeatability on simulated blade reconstruction paths
- 0.999 coefficient of determination for path linearity
- 8 mm diameter arm with protected fiber optic channel preventing bending damage
Why it matters
Enables precise, portable in-situ additive manufacturing for aeroengine blade repair, significantly reducing downtime and maintenance costs.
Abstract
Direct laser deposition, a form of additive manufac- turing, shows potential in numerous high-value applications such as aeroengine blade repair. However, conventional setups are bulky and unsuitable for in-situ repair, requiring costly engine disassem- bly. This letter presents a miniaturized high-repeatability tendon- driven robot that showed good potential for delivering additive manufacturing equipment for in-situ processes like direct laser deposition. The integrated actuation and ruggedized control unit make the robot portable and compatible with various aeroengines. The actuation design prevents excessive fiber optic bending and damage. While continuum robots have the advantage of flexible and redundant structures, they often lack accuracy and repeatability. The optimized kinematics and actuation of the robot presented per- mitted to achieve in controlled laboratory conditions an excellent repeatability with a standard deviation of 0.02 mm on a linear path and below 0.1 mm on a path that simulates the reconstruction of a blade. The robot showed excellent linearity on each segment of the path with a coefficient of determination to the 3D best-fit line of 0.999, while maintaining the commanded end effector velocity mag- nitude with a standard deviation of 0.05 mm/s along the whole path.