IIT

Prosthetic Wrist Unit

Active wrist prosthesis. Allows rotational movements in both directions. The gearbox is the strong point of this invention, with a planetary stage followed by a cycloidal one, with two opposing discs for mechanical balance.

Patent Status

PENDING

Priority Number

IT201800007400A

Priority Date

20/07/2018

License

INTERNATIONAL

Market

The advanced prosthetics was valued as $1.42 billion in FY 2018 and is forecasted to grow with a CAGR of 10.31% in the period of 2019-2024 and is estimated to be valued $2.55 billion in FY 2024.

Problem

The problem consists in the realization of an active prosthesis of the wrist in pronation-supination, composed of a commercial motor and a custom mechanical reducer that meets the high standards of compactness required, capable of guaranteeing the performance of a human wrist, silent operation and irreversibility of the system. with the engine off.

Nowadays, active wrist prostheses are underdeveloped, especially due to the difficulty of being able to create an active device compact enough to fit into the anthropometric encumbrances and into the patient’s cradle.

In addition to this, to be used by patients, the mechanism must meet high standards of strength and silence, and provide irreversibility of the system in the event that the user tries to turn the wrist with the engine off.

Current Technology Limits

In terms of commercial availability, most devices are passive, generally 1 or 2 DOF devices, with few motorized rotators available
Few rotary motors available
Most multi DOF wrists are serial mechanisms which, while simple to design and manufacture, are more prone to excessive length
Active wrists that can reach moments similar to the healthy human pulse can be quite heavy or long
Relatively compact active wrists have very low torque. This trade-off must be addressed in the development of more sophisticated wrist prostheses

Killer Application

This invention is intended for a prosthetic type application. a further application can be found in the field of humanoid robotics

Our Technology and Solution

This prosthetic wrist has a particular gearbox, connected to an electric motor: the first stage is epicyclic, operating with three friction wheels, and the second is cycloidal. This last stage uses two opposing discs (with an angle of 180 ° between them) with the typical shape of cycloidal applications, and a camshaft, to allow their reciprocating movement against the external profile. The resulting transmission is robust and rigid, with low play and a high ratio (264: 1) to weight and dimensions.

Double cycloidal / planetary stage
Eccentric drive shaft
Lobate discs

Advantages

High reduction ratio
High strength and transmissible torque
Structural and construction simplicity
High compactness of the union of the epicycloidal and cycloidal mechanisms
High degree of customization of the two-stage reduction system
Dynamic balance
Silence
Absence of vibrations
High resistance to mechanical shocks

Review the Technology

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Team

Paolo Rossi

Mechanical engineer working as a technician in the Hannes team, in the Rehab Technologies Lab

Paolo Rossi is a mechanical engineer working as a technician in the Hannes team and he is responsible for assembling, repairing and adjustments of the prototypes of prosthetic hand, elbow and shoulder developed in the Rehab Technologies Lab. He graduated in Mechanical Engineering in 2009 at the University of Genoa, focusing his studies on the design of wind turbines. He acquired significant experience in the general maintenance of industrial facilities and machinery, before arriving in the Rehab Lab in 2017 as a technician, with the aim of assembling and supporting the mechanical improvements of the prostheses and exoskeletons' prototypes of the lab.

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Lorenzo De Michieli

Head of the Rehab Technology Lab at the Italian Institute of Technology (IIT), an Innovation Lab co-funded by INAIL

Lorenzo De Michieli is the Head of the Rehab Technology Lab at the Italian Institute of Technology (IIT), an Innovation Lab co-funded by INAIL to develop new prostheses, exoskeletons and rehabilitation devices of high market potential in the healthcare sector.He received a M.S. in Physics in 1999, and a Ph.D. in Mechanical Engineering (Humanoid Robotics) from the University of Genoa, Italy. He also accomplished an extensive training on innovation management both in Italy at Jacobacci & Partners (Turin, IT) and abroad at the European Patent Office (The Hague, NL) and the Bergen Teknologioverføring (Bergen, N). From 2014 to 2019 he was contract Professor at the University of Genoa - Faculty of Economics - in Collaborative Innovation and Technology Transfer. He is currently Board member of Movendo Technology, one of the most promising biomedical companies in Italy.

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Nicolò Boccardo

Senior Mechatronic Engineer and Team Leader for the Hannes prosthetic System at the Rehab Technologies Lab.

His expertise lies in the development of novel mechatronic systems in the robotics and prosthetic field. He received his Master’s Degree in Robotics Engineering at Polytechnic School of Engineering of Genoa in 2013 with thesis developed at CERN concerning the position control of the collimation system for the particle beam of the LHC. After a brief experience in the transportation industry at Bombardier, he was involved in the development of the Hannes prosthetic System at the Italian Institute of Technology form 2014. Since then, he is actively involved into product development activities for technology transfer. Currently, he is the Team Leader of the upper limb prosthetic systems at the Rehab Technologies Lab, with main focus on hi-tech medical devices.

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Samuel Stedman

Mechanical Engineer working for the Hannes group at Rehab Technologies Lab

He specializes in the design and simulation of robotic and mechatronic devices, however he also has strong interests in the field of product design and product development. He received his Master’s degree in Mechanical Engineering and German at the University of Sheffield in 2015, whilst also studying for a year at TU Dresden. He worked for several years in the field of product management at BMW, before deciding to pursue his interest in robotics at IIT. Since joining in 2018 he has been responsible for the mechanical design, manufacture and testing of a 6 degree of freedom robotic arm and hand system for amputees. He is currently involved in several research and development activities at the Rehab Technologies Lab, focusing mainly on the development of mechanical systems for robotic prostheses and exoskeletons. In his spare time he regularly works on interesting and novel product ideas at the local Fablab, in addition to supporting a Red Crescent project that distributes 3D printed hand prostheses Syria.

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Michele Canepa

Senior Technician and Electronics Team Leader of the Rehab Technologies Lab.

His expertise lies in developing electrical and electronics system for medical robots. He received his master’s degree in Electrical Engineering at University of Genoa in 2014. After a brief experience in developing embedded measurements devices for a consulting firm, he joined the Rehab Technologies Lab as a Junior Technician, developing electronics and firmware for the first release of the Hannes prosthetic hand and the electronics for Twin, a lower-limb exoskeleton. In 2017 he joined the Rehab Technologies spin-off company, Movendo Technology, as Lead Electrical Engineer in R&D area: he oversaw various R&D, Industrialization and cost-reduction projects on the award-winning rehabilitation machine Hunova. He is currently involved in research development activities at the Rehab Technologies Lab, focusing on the development of electronics systems for robotic prostheses and orthoses.

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Andrea Marinelli

PhD student of research and development activities of iHannes project at the Rehab Technologies Lab

Andrea Marinelli is Biomedical PhD student of the iHannes project at Rehab Technologies Lab and of the DIBRIS department at the University of Genova. His expertise lies in the development of software and firmware architecture in the prosthetic field and Human-machine interfaces to translate human intention into prosthetic action. He received his Bachelor's Degree in Biomedical Engineering at Università Politecnica delle Marche in 2016 and a Master’s Degree in Neuroengineering at the University of Genova in 2019. After a brief experience as a research fellow in the robotics field at the Italian Institute of Technology, in 2019, he is a PhD student at the same institute from 2020. Since then, he is actively involved into the iHannes project to develop upper limb prosthetics high-tech. During his Master's thesis and currently PhD, he spent 4 years developing Pattern Recognition control strategies to translate muscle contraction into prosthetic movements. Currently, he is the PhD student of research and development activities of iHannes project at the Rehab Technologies Lab, with focus on closed-loop control strategies on prosthetic hand to provide proprioceptive sensations on users.

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Lorenzo Lombardi

Junior Electronics Engineer at Rehabilitation Technology Department

Electronics Engineer from Italy.In 2012 he joined Imperial College of London where he obtained his Master’s degree in Biomedical Engineering with Electronics. In 2017, he joined the Rehabilitation Technology Department at the Italian Institute of Technology as a Junior Electronics Engineer. Here he is responsible for the development of the electronics and firmware of the prosthetic upper-limb system Hannes. The application focuses on sensors (EMGs and IMUs), battery management and motor control. He is also involved in the validation of the robotic devices developed within the department and clinical trials with patients.

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