2020

A knee orthosis is an external medical device that is used to counter an impairment of the knee joint. These orthoses can provide stability, alignment and mechanical stress relief for ligaments, muscles and tendons and are designed for specific use cases. A novel approach was focused on an electro-adhesive clutch. This type of joint is made up of a combination of a clutch and a capacitor, where round electrode discs are placed on a shaft and separated by a dielectric material. Each electrode disc is fixed to a lever connecting the thigh, or the lower leg.

Under the application of high voltage, the electrostatic attraction force of the electrodes increases the compression force on the electrodes. In turn, this increases the friction at the electrode-dielectric interface and the stiffness of the whole knee orthosis. The controllability of this orthosis with the applied voltage makes it easily adaptable to the current patient condition, such as for an adaptable, post-operative rehabilitation process. Using printed circuit boards has been found to be a suitable solution for the core structure and electrode manufacturing. The Altium design and ordering process was supported by the Microelectronics Design Center of the ETH Zürich.