From Italy to Spain to advance learning-based control of legged robots

From late September to late October 2025, Giorgia Pazzi, research fellow at the University of Pisa, carried out her secondment at the Centro de Automática y Robótica (CAR) of the Spanish National Research Council (CSIC) in Madrid, within the NeutraWeed Project.

Her secondment focused on the development of advanced control systems for legged robots, with particular emphasis on gait trajectory tracking. The work explored a learning-based, model-free Iterative Learning Control (ILC) approach, enabling robots to iteratively improve their gait by learning from tracking errors observed during previous iterations.

During her stay, Giorgia implemented and evaluated the ILC framework in simulation, comparing its performance with a classical PID controller. The initial activities focused on trajectory tracking without considering ground contact forces, allowing the team to isolate and assess the behaviour of the control strategy. She also contributed to the development of benchmarking methodologies for evaluating legged locomotion performance on irregular and sloped terrains.

The secondment also provided valuable opportunities for scientific exchange and networking. Giorgia participated in the CAR research group meetings and engaged with researchers working across robotics and biomedical applications, gaining insights into how gait tracking challenges can be addressed across different robotic platforms and highlighting the multidisciplinary nature of legged locomotion research.

Preliminary results showed that the ILC controller can effectively reduce tracking errors when following smooth reference trajectories. However, more realistic gait trajectories, characterised by peaks and discontinuities, presented challenges for algorithm convergence and tracking accuracy. These findings highlight the importance of carefully designing reference trajectories and considering the physical constraints of real robotic systems.

The next phase of the research will focus on integrating contact dynamics and ground interaction forces into the ILC framework, with the ultimate goal of transferring the validated control strategy from simulation to real robotic hardware.

Giorgia’s secondment has strengthened collaboration between the University of Pisa and CSIC, contributing to the development of innovative, learning-based approaches for legged robot locomotion and creating new opportunities for future research and joint activities.

Stay tuned for more updates from the NeutraWeed international research community!