Exoskeleton design and adaptive compliance control for hand rehabilitation

Abstract

An adaptive robotic system has been developed to be used for hand rehabilitation. Previously developed exoskeletons are either very complex in terms of mechanism, hardware and software, or simple but have limited functionality only for a specific rehabilitation task. Some of these studies use simple position controllers considering only to improve the trajectory tracking performance of the exoskeleton which is inadequate in terms of safety and health of the patient. Some of them focus only on either passive or active rehabilitation, but not both together. Some others use EMG signals to assist the patient, but this time active rehabilitation is impossible unless different designs and control strategies are not developed. The proposed mechanical structure is extremely simple. The middle and the proximal phalanxes are used as a link of consecutively connected two 4-bar mechanisms, respectively. The PIP and MCP joints are actuated by a single electro mechanical cylinder to produce complex flexion and extension movements. It is simpler than similar ones from aspect with the mechanical structure and the biodynamic fit of the hand, making it practicable in terms of production and personal usage. Simple design lets to implement adaptive compliance controller for all active and passive rehabilitation tasks, instead of developing complex and different strategies for different rehabilitation tasks. Furthermore, using the Luenberger observer for unmeasured velocity state variable, an on-line estimation method is used to estimate the dynamic parameters of the system. This makes possible to estimate the force exerted by the patient as well, without a force sensor.

Towards collaborative drilling with a cobot using admittance controller

“…The research area that investigates how to integrate human and robot into tasks that involve physical interaction for improvements in performance is known as physical human-robot interaction (pHRI). From assembly tasks to furniture relocation in home/office setting (Mörtl et al, 2012), from industrial applications (Wojtara et al, 2009), surgery (Tabatabaei et al, 2019; Tavakoli et al, 2006) to rehabilitation (Akgun et al, 2020; Pehlivan et al, 2016), pHRI may bring high performance solutions to complex problems (please refer to extensive reviews by Ajoudani et al, 2018; Losey et al, 2018).…”

Data-Driven Predictive Control of Exoskeleton for Hand Rehabilitation with Subspace Identification

“…The linear actuator may move at a maximum speed of 12 mm per second and a maximum force of 45 N. A full hand opening or closing action requires roughly 5 s for a stroke of 50 mm. The mechanical structure and biodynamic fit of the hand make the designed system more practical in terms of usage and productivity than similar ones [ 2 , 23 , 24 ].…”

“…Specially designed hand rehabilitation robots are used to treat post-stroke hand movement limitations. These robots need to be made in accordance with the complex structure of the hand, which has about 20 degrees of freedom; it should also be supported by a robust and adaptive control algorithm so that it can function consistently for each patient [ 2 , 3 , 4 , 5 ]. Devices that support active rehabilitation can be used during the patient’s completely lost movement during the passive phase of the repetitive rehabilitation process.…”

“…In this instance, the control algorithm should find the best solution—not just any solution—for the targeted task while taking the constraints into account. Algorithms for model predictive control can be employed to achieve this [ 2 , 18 ].…”

Towards Collaborative Drilling with a Cobot Using Admittance Controller

“…The research area that investigates how to integrate human and robot into tasks that involve physical interaction for improvements in performance is known as physical human-robot interaction (pHRI). From assembly tasks to furniture relocation in home/office setting (Mörtl et al 2012), from industrial applications (Wojtara et al 2009), surgery (Tavakoli et al 2006;Tabatabaei et al 2019) to rehabilitation (Pehlivan et al 2016;Akgun et al 2020), pHRI may bring high performance solutions to complex problems (please refer to extensive reviews by Ajoudani et al 2018;Losey et al 2018).…”