Our Latest Results on Exoskeletons and Assistive Robots

This video presents an adaptive EMG-driven gravity compensation algorithm that automatically adjusts the level of assistance based on the muscular activation of the biceps and triceps. One of the key features of the approach is its ability to work in synergy with the human and to automatically adapt to the operator’s needs: both the human and the robot work towards the same goal in a synergistic manner, creating a system of human-in-the-loop optimization. The video shows how the system significantly reduces the muscular activation of a healthy subject, providing nearly full assistance during movement. This level of performance and high assistance is not achievable with other methods in the literature (e.g., proportional EMG-based approaches).

Dimo, E., Costanzi, D., Pascucci, F., & Calanca, A. (2025). Myography-Based Adaptive Gravity Compensation Strategies for Powered Upper-Limb Exoskeletons. Submitted 

This video shows an initial application of the AGtuator concept on a wearable exoskeleton. The video displays preliminary results of the mechanical design.

Article in progress

This video presents an innovative actuation concept that we have named AGtuator (Anti-Gravity actuator), capable of compensating for gravitational forces acting on a robotic link without energy consumption. The system can be reconfigured for different loads and is not intended merely as a gravity compensation mechanism. It is capable of generating arbitrary force profiles by dynamically reconfiguring the spring according to the required forces. This is a truly unconventional force control system, whose theoretical stability properties are analyzed in the following article:

Pascucci, F., Dimo, E., & Calanca, A. A Semi-Active Actuator for Adjustable Gravity Compensation. To be submitted soon

This video presents an innovative friction compensation system for force control applications, featuring unparalleled robustness (passivity) in the literature. The video shows the application of the algorithm on an elbow exoskeleton that compensates for the user’s arm weight. Note the extremely accurate compensation. Thanks to the elimination of friction-related artifacts, the system exhibits very high transparency. In our experience, this represents a key feature for assisting individuals with muscular weakness, who report the sensation of feeling “as if in a bubble”.

Dimo, E., & Calanca, A. (2025). A Model Reference Friction Observer for Friction Compensation and Shaping in Interaction Control. Submitted to IEEE Robotics and Automation Letters.

This video presents a friction compensation system developed for benchmarking applications. While it demonstrates unmatched robustness (passivity), it requires precise knowledge of the mechanical characteristics of the interacting system—an assumption that holds in benchmarking scenarios but not in real-world applications. The above video, however, shows an equivalent solution that eliminates the need for prior knowledge. The system operates effectively under unknown environmental conditions.

Dimo, E., & Calanca, A. (2024). Environment Aware Friction Observer with Applications to Force Control Benchmarking. Actuators, 13(53).

This video shows experimental tests on the AGADEXO industrial exoskeleton, developed by AGADE s.r.l. It is one of the first active shoulder exoskeletons to be commercialized and used in industrial contexts. For a detailed evaluation of its effectiveness, see the following article:

Pascucci, F., Feola, E., Cesari, P., & Calanca, A. (2025). Evaluation of a Semi-Active Upper-Limb Exoskeleton while Performing Material Handling Tasks. IEEE Transactions on Medical Robotics and Bionics.

This video presents robotic assistance experiments for a muscular dystrophy patient: Davide Costanzi. Davide, currently a post-doctoral researcher in our lab, is both the designer and the user of the system. The video shows that while traditional gravity compensation approaches offer good usability, they fail to cope with unknown external loads. Alternative approaches based on surface electromyography allow Davide to lift arbitrary loads. This is because the EMG signal originates from Davide’s brain, which is highly adaptable to the surrounding context. Unfortunately, the EMG signal is very noisy and neuromuscular delays may cause oscillations, limiting the system usability.

D. Costanzi, M. Gandolla, and A. Calanca, “Towards Personalized Myoelectric Control Strategies,” in 2023 IEEE International Conference on Metrology for eXtended Reality, Artificial Intelligence and Neural Engineering (MetroXRAINE), 2023, p. 6.

This video presents a possible solution to the non-collocation problem. Typically, the presence of dynamics—such as those introduced by gear reducers—between the actuator and the force sensor imposes significant limitations on the choice of control gains. It is well known that increasing the force control gains can lead to oscillations and instability, especially when interacting with environments of varying stiffness. The solution demonstrated in the video shows that it is possible to achieve very high force gains in contact with both extremely rigid and highly compliant environments.

The manuscript is in preparation and builds upon the results presented in A. Calanca and P. Fiorini “A Rationale for Acceleration Feedback in Force Control of Series Elastic Actuators” IEEE Transactions on Robotics

This video presents a possible kinematic solution for extending our robotic concept (shown in the video below) to multiple degrees of freedom and functional tasks. By introducing an additional elbow degree of freedom, the system preserves its passive gravity compensation capabilities across three dimensions.

Article in progress