Design, Prototyping, and Testing of a Robotic Prosthetic Leg

The purpose of this graduate student research study is to test that a specifically designed and novel robotic prosthetic leg (RPL) is feasible, safe and improves symmetry, efficiency, and metabolic function during sit-to-stand and stand-to-sit transitions as compared to the subject's prescribed device, and as compared to no device at all.

Phase 2 case study Two subjects will be fitted with a heart rate monitor and with an adapted waist belt with mobile phone attached. RPL alignment will be verified. The subjects will use the RPL in parallel bars 10 times and take rests as needed in a chair. The subjects will perform the timed up and go test (TUGT), 10-meter walk test (10MWT), and the 6-minute walk test (6MWT). The subjects will be fitted with retro-reflective markers. The subjects will be fitted with a portable oxygen uptake analyzer. A 4D motion-capture camera system will be used while performing TUGT and five times sit to stand (5XSTS). The subjects will perform the above tests in their prescribed daily-wear prosthesis, and then in the RPL. The subjects will complete the activities-based balance confidence (ABC) scale test. The subjects will be asked a series of open-ended questions regarding the experience, while being audio recorded. Phase 3 pilot study Twenty subjects will be randomized into three treatment arms (no prosthesis, prescribed prosthesis, RPL). The subject will be fitted with a heart rate monitor. The subject will be fitted with a portable oxygen uptake analyzer. The subject will be fitted with the RPL, and the alignment of the RPL will be confirmed before testing. The subject will be fitted with retro-reflective markers. A 4D motion-capture camera system and force-plate will be used while performing the 5XSTS test in the assigned randomized condition. The test will be performed three times in each condition. The subject will return two more times to complete the tests in the remaining randomized conditions, with a two-week washout period between sessions. The subject will be given the ABC scale test in the beginning and at the end of this study. The subject will complete the technology attitudes questionnaire (TAQ). In total, subject participation will last 1 hour per day, for three sessions, two weeks apart.

The RPL consists of a passive-dynamic ankle, powered knee, and an on-board inertial measurement sensors with an on-board kinetic and kinematic data collection system for analysis.

The RPL consists of a passive-dynamic ankle, powered knee, and an on-board inertial measurement sensors with an on-board kinetic and kinematic data collection system for analysis.

The participant sits in a standard armchair with any assistive device used for walking nearby. The participant stands and at a self-selected walking speed, walks 3 meters, turns, and walks back to the chair, and sits down. A stopwatch records the time to of the test (in seconds).

The participant will be timed as he/she walks a known distance of 10 meters to determine his/her self-selected walking velocity (distance/time).

Phase 2 Inclusion Criteria: unilateral limb-loss. amputation or knee disarticulation/transfemoral amputation can walk with a variable cadence (Level K3) or play sports (Level K4) uses a prosthesis for walking daily can stand for 30 seconds on one limb can follow one-step commands. Exclusion Criteria: Those who can not walk with a variable cadence (Level K1 and K2) compromised skin on the residual limb (stump) uncontrolled swelling missing more than one limb Phase 3 Inclusion Criteria: unilateral knee disarticulation or transfemoral amputation. can walk at a single speed (Level K2), can walk with a variable cadence (Level K3) or play sports (Level K4) can follow one step commands. Exclusion Criteria: Those who do not use prosthesis for walking (Level K1) compromised skin on the residual limb (stump) uncontrolled swelling missing more than one limb