Videogallery - 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 a wearable exoskeleton based on the AGtuator concept. The video displays preliminary implemetation 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. Submitted

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

This video presents the implementation of a rehabilitation system which learn the rehabilitation trajectories set by th therapist. It is developed based on th exoskeleton described in the video below.

Palazzi et al., “An Affordable Upper-Limb Exoskeleton Concept for Rehabilitation Applications,” Technologies, vol. 10, no. 1, p. 22, 2022.

This video shows the development of an ultra-low-cost rehabilitative exoskeleton. The mechanical design implements gravity compensation using elastic elements to substantially reduce motor requirements and their cost (saving approximately €1500 per joint). The 3D-printed links allow for the inclusion of affordable force sensors (saving around €1000 per joint). The system features a smart mechatronic architecture which lead to high-performance force control, aiming to gently and precisely assist the user.

Calanca, E. Dimo, E. Palazzi, L. Luzi, “Enhancing Force Controllability by Mechanics in Exoskeleton Design,” Mechatronics, vol. 86, 2022.

This video shows an experimental setup developed by two students during a university project. It is a single-link robotic system with torque control capabilities comparable to those of high-end industrial systems. The system was built using a plastic link and low-cost electronics. The design is inspired by a concept we called Series Elastic Link (SEL), described in the following article.
Calanca, E. Dimo, R. Vicario, P. Fiorini, M. Serpelloni, and G. Legnani “Introducing Series Elastic Links for Affordable Torque-Controlled Robots” Robotics and Automation Letters, vol. 4, no. 1, pp. 137–144, 2019.

This video presents examples of impedance control on a Series Elastic Actuator (SEA). In simple terms, these algorithms allow to virtually modify the system’s stiffness. Although the physical system has an elastic constant K1, it behaves as if it had a different stiffness K2. The ability to impose an arbitrary elastic constant K2 while maintaining system stability enables to virtualize the “softness” of a robotic system. This technology may be considered speculative, but is actually the foundation of nearly all the videos on this page. One of our related publications is:

Calanca, R. Muradore, P. Fiorini “Impedance Control of Series Elastic Actuators: Passivity and Acceleration-Based Control” Mechatronics, vol. 47, pp. 37–48, 2017.

This video presents an extremely simple control algorithm capable of initiating the gait of a simplified biped model. The most interesting aspect of this work is that the algorithm enables the emergence of a locomotor pattern from the passive dynamics of the system. This work is related to the development of lower-limb exoskeletons.

This video shows a prototype of a robotic lower-limb orthosis designed for children with cerebral palsy. The system is a walker actuated by pneumatic systems that mimic human muscle activation dynamics. The system is non-coercive; through force control technologies, we do not impose a motor pattern but allow the user to express anticipatory signals of gait, supporting rather than forcing movement. The video shows how, throughout the experimentation phases, the subject learns new gait patterns. By the end of the trial, the subject was able to walk autonomously on the system even with the actuators turned off (stimulating brain plasticity)

Calanca, A. Cosentino, P. Fiorini “A motor learning oriented, compliant and mobile Gait Orthosis” Applied Bionics and Biomechanics, vol. 9, no. 1, pp. 15–27, 2012
N. Smania, M. Gandolfi, V. Marconi, A. Calanca et al. “Applicability of a new robotic walking aid in a patient with cerebral palsy” European Journal of Physical and Rehabilitation Medicine, vol. 47, no. 0, pp. 1–7, 2011.