Current Projects

Passive and Semi-Passive Devices for Gait Rehabilitation

Our lab has developed several fully passive and semi-passive devices for gait rehabilitation. These devices use eddy current brakes to provide velocity-dependent resistance during walking. The short-term and long-term effects of these devices are being tested in able-bodied as well as in individuals with neurological or orthopedic injuries.

Passive Elastic Leg Exoskeleton for Resistive Gait Rehabilitation

Gait impairments are a prominent source of disability after neurological or orthopedic injuries. Applying functional resistance training during walking is an emerging method for treating individuals with gait impairments. This training is administered by having a patient perform a task-specific training (in this case, walking) while a load is applied to resist the movement. This works simultaneously to improve muscle strength and coordination, which are often underlying sources of gait impairment. While there are several robotic solutions for this type of training, these devices are often too expensive for use in small clinics or in the home. Hence, we developed a unique, low-cost, passive exoskeleton to provide different types of elastic resistances (i.e., resisting flexion, extension, or bidirectionally) to the leg muscles during walking. This device uses a system of counteracting compressional springs, pulleys, and clutches to provide these different types of elastic resistance. We have shown that this device could specifically target knee flexors, extensors, or both, and increase eccentric loading at the joint. Additionally, these resistance types elicited different kinematic aftereffects that could be used to target user-specific spatiotemporal gait deficits. Hence, the device provides a potential low-cost option for addressing user-specific muscle weaknesses and gait deficits during functional resistance training.

Acute Biomechanical and Neurophysiological Adaptations after Functional Resistance Training

In this project, we seek to determine how functional resistance training using different resistance types acutely promotes biomechanical and neurophysiological adaptations during gait in able-bodied and individuals with stroke or ACL-reconstruction.

Passive Rehabilitation Robot (PaRRo) for Upper-Extremity Functional Resistance Training

In this project, we use eddy current brakes and exploit kinematic redundancies to provide direct resistive forces during planar reaching. Because there are no active actuators (i.e., motors) and the device can be mounted easily on a simple table, the device is expected to be more affordable and safe for in-home use.

Semi-Passive Rehabilitation Robot (SepaRRo) for Upper-Extremity Rehabilitation

Robotic rehabilitation is a promising approach to treat individuals with neurological or orthopedic disorders. However, despite significant advancements in the field of rehabilitation robotics, this technology has found limited traction in clinical practice. A key reason for this issue is that most robots are expensive, bulky, and not scalable for in-home rehabilitation. Here, we introduce a semi-passive rehabilitation robot (SepaRRo) that uses controllable passive actuators (i.e., brakes) to provide controllable resistances at the end-effector over a large workspace in a manner that is cost-effective and safe for in-home use. We also validated the device through theoretical analyses, hardware experiments, and human subject experiments. We found that by including kinematic redundancies in the robot's linkages, the device was able to provide controllable resistances to purely resist the movement of the end-effector, or to gently steer (i.e., perturb) its motion away from the intended path. When testing these capabilities on human subjects, we found that many of the upper-extremity muscles could be selectively targeted based on the forcefield prescribed to the user. These results indicate that SepaRRo could serve as a low-cost therapeutic tool for upper-extremity rehabilitation; however, further testing is required to evaluate its therapeutic benefits in patient population.

Low-Cost Virtual Reality for Rehabilitation

In this project, we are creating an open source, virtual reality system for upper- and lower-extremity rehabilitation. The virtual reality system (NeuRRoVR) has several in-built games and interfaces to provide several existing and novel therapies (e.g., mirror therapy, bimanual therapy, hand therapy, balance and coordination training) and also perform neuromuscular evaluations (e.g., Box and Block Test, joint excursions).

Mechanical Impedance of Ankle during Standing and Walking

In this project, we use a mechanical perturberator to provide controlled perturbations to the ankle during standing and walking and use Least-squares System Identification techniques to quantify the mechanical impedance of the ankle. We are evaluating the effects of muscle activation, ageing, stroke, and Botulinum Neurotoxin on ankle mechanical impedance during standing and stance phase of walking.