Brain–computer interface and assist-as-needed model for upper limb robotic arm

Abstract

Post-stroke paralysis, whereby subjects loose voluntary control over muscle actuation, is one of the main causes of disability. Repetitive physical therapy can reinstate lost motions and strengths through neuroplasticity. However, manually delivered therapies are becoming ineffective due to scarcity of therapists, subjectivity in the treatment, and lack of patient motivation. Robot-assisted physical therapy is being researched these days to impart an evidence-based systematic treatment. Recently, intelligent controllers and brain–computer interface are proposed for rehabilitation robots to encourage patient participation which is the key to quick recovery. In the present work, a brain–computer interface and assist-as-needed training paradigm have been proposed for an upper limb rehabilitation robot. The brain–computer interface system is implemented with the use of electroencephalography sensor; moreover, backdrivability in the actuator has been achieved with the use of assist-as-needed control approach, which allows subjects to move the robot actively using their limited motions and strengths. The robot only assists for the remaining course of trajectory which subjects are unable to perform themselves. The robot intervention point is obtained from the patient’s intent which is captured through brain–computer interface. Problems encountered during the practical implementation of brain–computer interface and achievement of backdrivability in the actuator have been discussed and resolved.

State-of-the-Art Assistive Powered Upper Limb Exoskeletons for Elderly

“…Also, controlling the trajectory of the joint results in the stiffness of an exoskeleton [98]. Impedance control cause users to feel less inertial forces during the usage of assistive exoskeletons by providing required assist-asneeded motions and allowing exoskeletons to actively follow human movements [99][100][101]. EMG based AAN impedance control was integrated in the 7 DOF upper limb assistive exoskeleton (presented in Table 1) by Kiguchi et al The experimental results suggest that this approach can be adapted to any user [71].…”

Assist as Needed Control Strategy for Upper Limb Rehabilitation Robot in Eating Activity

“…Several Assist As Needed control techniques have been formulated for lower and upper limb rehabilitation treatments for various types of patients [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. Gui et al introduced the progressive Assist As Needed (pAAN) controller for a lower limb exoskeleton system.…”

“…The Assist as Needed control scheme for upper limb rehabilitation [13][14][15][16][17][18][19][20][21][22][23][24][25] was included in the works by Pérez-Rodríguez et al [13]. It was composed of three subsystems: (1) biomechanical prediction, (2) assistance decision, and (3) command generation.…”

“…The technique enabled the patients to move the robot utilizing the limited motion and strength that they had and the robot assisted for the remaining course of trajectory that they were unable to perform by themselves. [14]. The major challenge in AAN control strategy is to effectively determine the patients' movement/functional ability, and then to adjust the robot assistance consistently with the changes in the patients' movement abilities [15,16].…”

End-effector wheeled robotic arm gaming prototype for upper limb coordination control in home-based therapy

“…The other researcher focused on studying the mechanical design of the robot used for treatment and how significant the impact of the robot toward rehabilitation process. It covers the model of interaction between man and robot, how the control is ignited, and how the training model is performed [15][16][17][18][19][20]. Rehabilitation using robotic generally divided into cluster end-effector (EE) and exoskeleton (Exo) robot according to mechanical construction of the robot [8].…”