Design of Wheelchair Robot for Active Postural Support (WRAPS) for Users with Trunk Impairments

People with severe trunk impairments cannot maintain or control upright posture during sitting or reaching out with the upper body. Passive orthoses are clinically available to support the trunk and promote the use of upper extremities in this population. However, these orthoses only rigidly position the torso on a wheelchair but do not facilitate movement of the trunk. In this dissertation, we introduce a novel active-assistive torso brace system for upperbody movements by a subject while seated. We have named this system as Wheelchair Robot for Active Postural Support (WRAPS). We propose designs of two robots, one for the pelvis and the other for the trunk. Each of the two devices has a parallel chain architecture to accommodate the range of motion (ROM), respectively for the pelvic and thoracic segments. The first thoracic robot was designed for the upper trunk motion relative to the pelvis. It has a 2[RP]S-2UPS architecture which provides four degrees-of-freedom (DOFs) to the end-effector placed on the upper trunk. The second is a pelvic robot which is designed to orient the pelvic segment relative to the seat. It has a 3-DOF [RRR]U-2[RR]S architecture, coupled with translation to accommodate pelvic movements relative to the seat. These robot architectures are synthesized based on human movement data. WRAPS can modulate the displacement of both the pelvic and the thoracic segments. Additionally, the forces can be applied on the torso through the end-effectors of these robots. Each of the robot prototypes was evaluated with able-bodied subjects to assess the device wearability, kinematic performances, and control system

Robotic Exoskeletons for Torso Study, Training, and Assistance

Robotic exoskeletons are important tools in medicine for characterizing certain aspects of diseases, enabling physical therapy treatments, or providing assistance to those with impairments. One area in particular where these devices can make an impact is the study and treatment of scoliosis. First, I adapt a design of a robotic torso exoskeleton to serve the population most susceptible to scoliosis, female adolescents. I used the device to compare the torso stiffness of members of this group with and without scoliosis, and found an interaction effect of degree of freedom (DOF) and torso segment on translational stiffness, and an interaction effect of DOF and group on rotational stiffness. These results can inform the models used to create rigid orthoses for conservative treatment or to simulate the effects of surgical procedures. Second, I explore the effects of different types of augmented sensory feedback commonly used in scoliosis physical therapy. I compare visual and force feedback provided by the exoskeleton on one’s ability to replicate static poses and dynamic movements. I find that while force feedback leads to faster initial improvement, visual feedback may enable the user to learn finer details of the movement. Third, I design a torso exoskeleton for people with neuromotor impairments. People who are not able to sit up independently are at a high risk of developing neuromuscular scoliosis, and must balance the benefits of treatment with rigid orthoses, with the limits that these devices place on functional movements. The device allows users four degrees of freedom, to support functional movements such as reaching and pressure relief maneuvers, but prevents lateral translation and axial rotation, which can contribute to neuromuscular scoliosis. Together, these results demonstrate the potential for robotic exoskeletons in torso study, training, and assistance

Proceedings of the 5th international conference on disability, virtual reality and associated technologies (ICDVRAT 2004)

The proceedings of the conferenc