Design of a series visco-elastic actuator for multi-purpose rehabilitation haptic device

<p>Abstract</p> <p>Background</p> <p>Variable structure parallel mechanisms, actuated with low-cost motors with serially added elasticity (series elastic actuator - SEA), has considerable potential in rehabilitation robotics. However, reflected masses of a SEA and variable structure parallel mechanism linked with a compliant actuator result in a potentially unstable coupled mechanical oscillator, which has not been addressed in previous studies.</p> <p>Methods</p> <p>The aim of this paper was to investigate through simulation, experimentation and theoretical analysis the necessary conditions that guarantee stability and passivity of a haptic device (based on a variable structure parallel mechanism driven by SEA actuators) when in contact with a human. We have analyzed an equivalent mechanical system where a dissipative element, a mechanical damper was placed in parallel to a spring in SEA.</p> <p>Results</p> <p>The theoretical analysis yielded necessary conditions relating the damping coefficient, spring stiffness, both reflected masses, controller's gain and desired virtual impedance that needs to be fulfilled in order to obtain stable and passive behavior of the device when in contact with a human. The validity of the derived passivity conditions were confirmed in simulations and experimentally.</p> <p>Conclusions</p> <p>These results show that by properly designing variable structure parallel mechanisms actuated with SEA, versatile and affordable rehabilitation robotic devices can be conceived, which may facilitate their wide spread use in clinical and home environments.</p

Universal haptic drive system (US)

A universal haptic drive system for arm and wrist rehabilitation is described comprising a hand accessory and a vertical handle for carrying the hand accessory, the vertical handle being movable in a transversal plane. It furthermore comprises a haptic actuator system for applying a force to the vertical handle. The vertical handle comprises a universal joint with locking ability. When the universal joint is unlocked, it enables movements for wrist rehabilitation, and when it is locked it causes a stiff substantially vertical handle enabling movements for arm rehabilitation.ApplicationFundación Fatroni

Universal haptic drive system (ES)

A universal haptic drive system for arm and wrist rehabilitation is described comprising a hand accessory and a vertical handle for carrying the hand accessory, the vertical handle being movable in a transversal plane. It furthermore comprises a haptic actuator system for applying a force to the vertical handle. The vertical handle comprises a universal joint with locking ability. When the universal joint is unlocked, it enables movements for wrist rehabilitation, and when it is locked it causes a stiff substantially vertical handle enabling movements for arm rehabilitation.GrantedFundación Fatroni

Universal haptic drive system (ES)

A universal haptic drive system for arm and wrist rehabilitation is described comprising a hand accessory and a vertical handle for carrying the hand accessory, the vertical handle being movable in a transversal plane. It furthermore comprises a haptic actuator system for applying a force to the vertical handle. The vertical handle comprises a universal joint with locking ability. When the universal joint is unlocked, it enables movements for wrist rehabilitation, and when it is locked it causes a stiff substantially vertical handle enabling movements for arm rehabilitation.GrantedFundación Fatroni

Universal haptic drive system (EP)

A universal haptic drive system for arm and wrist rehabilitation is described comprising a hand accessory and a vertical handle for carrying the hand accessory, the vertical handle being movable in a transversal plane. It furthermore comprises a haptic actuator system for applying a force to the vertical handle. The vertical handle comprises a universal joint with locking ability. When the universal joint is unlocked, it enables movements for wrist rehabilitation, and when it is locked it causes a stiff substantially vertical handle enabling movements for arm rehabilitation.GrantedFundación Fatroni

Development of an Apparatus for Bilateral Rhythmical Training of Arm Movement Via Linear and Elliptical Trajectories of Various Directions

Clinical rehabilitation of individuals with various neurological disorders requires a significant number of movement repetitions in order to improve coordination and restoration of appropriate muscle activation patterns. Arm reaching movement is frequently practiced via motorized arm cycling ergometers where the trajectory of movement is circular thus providing means for practicing a single and rather nonfunctional set of muscle activation patterns, which is a significant limitation. We have developed a novel mechanism that in the combination with an existing arm ergometer device enables nine different movement modalities/trajectories ranging from purely circular trajectory to four elliptical and four linear trajectories where the direction of movement may be varied. The main objective of this study was to test a hypothesis stating that different movement modalities facilitate differences in muscle activation patterns as a result of varying shape and direction of movement. Muscle activation patterns in all movement modalities were assessed in a group of neurologically intact individuals in the form of recording the electromyographic (EMG) activity of four selected muscle groups of the shoulder and the elbow. Statistical analysis of the root mean square (RMS) values of resulting EMG signals have shown that muscle activation patterns corresponding to each of the nine movement modalities significantly differ in order to accommodate to variation of the trajectories shape and direction. Further, we assessed muscle activation patterns following the same protocol in a selected clinical case of hemiparesis. These results have shown the ability of the selected case subject to produce different muscle activation patterns as a response to different movement modalities which show some resemblance to those assessed in the group of neurologically intact individuals. The results of the study indicate that the developed device may significantly extend the scope of strength and coordination training in stroke rehabilitation which is in current clinical rehabilitation practice done through arm cycling

An Exoskeleton Design Robotic Assisted Rehabilitation: Wrist & Forearm

Robotic systems are being used in physiotherapy for medical purposes. Providing physical training (therapy) is one of the main applications of fields of rehabilitation robotics. Upper-extremity rehabilitation involves shoulder, elbow, wrist and fingers’ actions that stimulate patients’ independence and quality of life. An exoskeleton for human wrist and forearm rehabilitation is designed and manufactured. It has three degrees of freedom which must be fitted to real human wrist and forearm. Anatomical motion range of human limbs is taken into account during design. A six DOF Denso robot is adapted. An exoskeleton driven by a serial robot has not been come across in the literature. It is feasible to apply torques to specific joints of the wrist by this way. Studies are still continuing in the subject. © 2019, Springer Nature Switzerland AG

Adaptive Dynamic Balance Training During Overground Walking with Assistive Device

Abstract-In this paper we describe a motorized device and corresponding adaptive control strategy for dynamic balance training during overground walking. The device provides adjustable level of supporting forces at the pelvis whereas adaptive control strategy periodically adjusts the training difficulty by adjusting gait velocity with respect to selected performance criterion. Results suggest that the proposed training paradigm may successfully ascertain training conditions that correspond well to patient capabilities and therefore may potentially be useful in improving dynamic balance during overground walking in gait rehabilitation of neurological individuals

Feasibility

study for cell electroporation detection and separation by means of dielectrophoresi