Design of a Cable-Driven Hyper-Redundant Robot with Optimal Cable Routing

Currently, inspection and maintenance operations in industrial and infrastructure environments are conducted by operators. Such inspections should be carried out in hazardous locations or in scenarios where conditions are extreme for humans. In this context, inspection robotics is extremely helpful, reducing the operator's risks and the intervention times. In this thesis work, a new cable-driven hyper-redundant robot design is studied. Thanks to the hyper-redundancy, these robots can access restricted spaces avoiding obstacles along the path. In addition to reducing the weight of the robot, the cable actuation allows the system to enter places where temperatures are high. This novel cable-driven hyper-redundant robot is fully actuated. It features a pulley-less design because it does not require a free pulley to route the cables within its structure. Part of the work describes the joint design of the robot and related experiments. Another part of the work regards kinematics and forces modelling. The decoupling of the cable kinematics is presented and analysed for a robot with n DOF. A cable routing optimisation methodology based on multi-objective genetic algorithms is presented. This methodology is then applied to both a 5 DOF and a 10 DOF robot. In the latter case, the optimisation is preceded by a sensitivity analysis to reduce the optimisation variables. Two novel linear actuators are presented. Their designs are based on the results obtained in the optimisation process. The robot is then simulated within two industrial scenarios. The first scenario is the inspection of a gas turbine combustion chamber, a case study for Ansaldo Energia company. The second concerns a frequent industrial scenario, namely the inspection of weld seams of pressurised tanks located in places inaccessible to humans. Finally, a design of experiments with multiple objectives is proposed. The first goal is to validate the kinematics and statics model and implement contingency action to solve any problems. The second objective is to evaluate robot design using standard performance indicators based on UNI EN ISO 9283:1999.