Variable structure pantograph mechanism with spring suspension system for comprehensive upper-limb haptic movement training

Abstract

Abstract-Numerous haptic devices have been developed for upper-limb neurorehabilitation, but their widespread use has been largely impeded because of complexity and cost. Here, we describe a variable structure pantograph mechanism combined with a spring suspension system that produces a versatile rehabilitation robot, called Universal Haptic Pantograph, for movement training of the shoulder, elbow, and wrist. The variable structure is a 5-degree-of-freedom (DOF) mechanism composed of 7 joints, 11 joint axes, and 3 configurable joint locks that reduce the number of system DOFs to between 0 and 3. The resulting device has eight operational modes: Arm, Wrist, ISO (isometric) 1, ISO 2, Reach, Lift 1, Lift 2, and Steer. The combination of available work spaces (reachable areas) shows a high suitability for movement training of most upperlimb activities of daily living. The mechanism, driven by series elastic actuators, performs similarly in all operational modes, with a single control scheme and set of gains. Thus, a single device with minimal setup changes can be used to treat a variety of upper-limb impairments that commonly afflict veterans with stroke, traumatic brain injury, or other direct trauma to the arm. With appropriately selected design parameters, the developed multimode haptic device significantly reduces the costs of robotic hardware for full-arm rehabilitation while performing similarly to that of single-mode haptic devices. We conducted case studies with three patients with stroke who underwent clinical training using the developed mechanism in Arm, Wrist, and/or Reach operational modes. We assessed outcomes using Fugl-Meyer Motor Assessment and Wolf Motor Function Test scores showing that upper-limb ability improved significantly following training sessions.

Interaction force and motion estimators facilitating impedance control of the upper limb rehabilitation robot

“…One of its main advantages is the possibility of varying its mechanical structure through the use of three lockable/unlocking joints. This allows eight different modes of training, which can be used to rehabilitate all joints of the upper limb [18]. Among these eight mechanical configurations or modes of operation, this work focuses on one of the most used, the ARM mode, in which the UHP executes planar flexion/ extension motions of the arm through 2 degrees of freedoms (DOF) movement in quasi x-y plane [18], allowing to rehabilitate the three movements of the shoulder (rotation, flexion/extension and abduction/adduction) and the flexion/extension movement of the elbow.…”

“…So in this work, we present interaction force and motion estimators for one of upper-limb rehabilitation robots, Universal Haptic Pantograph (UHP), which has been shown in several publications [18], [19], [20]. The UHP is an innovative rehabilitation robot for complete upper limb training and used for the rehabilitation of shoulders, elbows and wrists in people who suffer motor disability after a stroke.…”

Robotic Wrist Rehabilitation With High-density Electromyographic Biofeedback for Reducing Co-activation of Antagonist Muscles and Improved Motor Coordination: A Feasibility Study

“…1 right). The robot provided linear resistance de ned by the spring-force mechanism [15] during the wrist movement. We estimated that the applied wrist force had been adequate to the UHD's resisting force also measured in all three dimensions.…”

Dispositivo Robótico Multifuncional para la Rehabilitación de las Extremidades Superiores

“…Por tanto, se utiliza para la rehabilitación de hombros, codos y muñecas en personas que sufren discapacidad motora debido a un ataque cerebrovascular o ictus. Una de sus ventajas principales es la posibilidad de variar su estructura mecánica mediante el uso de tres articulaciones bloqueables/desbloqueables (B, D y E) (Figura 1), lo que permite configurar hasta ocho modos de funcionamiento (Perry et al, 2011). Entre estas ocho configuraciones mecánicas o modos de funcionamiento que posee, en este artículo se detallarán las dos más usadas: los modos ARM (Brazo) y WRIST (Muñeca).…”