Design of Modular Actuators for Innovative Robots

Robots are widely used across various sectors and require a range of capabilities, from highspeed dynamic actions to gentle, precise movements. At the core of these capabilities are actuators, which enable complex movements with precision and resilience. Ideal actuators combine high torque density with inherent compliance, providing both power and adaptability. These qualities allow robots to maintain stability and control in dynamic environments, making actuators a central focus in advancing robotic functionality and versatility. This thesis investigates two complementary approaches to developing cost-effective actuator solutions for dynamic robotic systems: (1) optimizing existing, conventional actuators and (2) designing novel actuators that offer affordability and flexibility to meet specific design goals. The first approach focuses on enhancing established actuator designs to balance cost efficiency with high functionality. Here, two modular actuator models are introduced—M-Act and Elastic M-Act (EM-Act)— which are tailored for legged and multimodal robots requiring dynamic movements. The development process involves defining jump height as a performance metric, identifying optimal parameters through simulations, and selecting and testing mechatronic components. Additionally, the EM-Act design incorporates integrated compliance, which minimizes impact forces during operation and enhances longevity and robustness. The thesis details the practical implementation of both actuator solutions on a two-degree-of-freedom robotic leg and presents experimental validation of their jumping capabilities, demonstrating their effectiveness in real-world applications. The second approach explored in this research emphasizes innovative actuator designs, culminating in the development of RM-Act and RM-Act 2.0. This research focuses on developing speed reducers that offer the typical advantages of conventional harmonic drives while avoiding their complex components. The novel design also improves the range of speed reduction ratios available in harmonic speed reducers. A comprehensive description of the actuation principle, theoretical foundations, and technical specification is provided. Prototype testing is conducted to validate the RM-Act and RM-Act 2.0 models. This innovative design offers an affordable alternative to traditional harmonic actuators, expanding access to advanced robotic functionalities. The actuator solutions presented in this thesis constitute helpful resources for academics and developers as they offer affordable alternatives for implementing advanced actuators in practical applications. Ultimately, the advancements presented here are expected to improve progress in the field of robotics, paving the way for more agile, adaptable, and affordable robotic solutions that can be effectively utilized across diverse sectors.