Category: News

Volitional control systems for powered prostheses require the detection of user intent to operate in real-life scenarios. Ambulation mode classification has been proposed to address this issue. However, these approaches introduce discrete labels to the otherwise continuous task which is ambulation. An alternative approach is to provide users with direct, voluntary control of the powered prosthesis motion. In this study, we show that a small and lightweight A-mode ultrasound system can continuously predict prosthesis joint kinematics in seven individuals with transfemoral amputation across different ambulation tasks. Features from the A-mode ultrasound signals were mapped to the user’s prosthesis kinematics...

Kuntz Lab paper, “Toward Continuum Robot Tentacles for Lung Interventions: Exploring Folding Support Disks” has been published in the IEEE Robotics and Automation Letters (RA-L)....

Passive prostheses are able to dissipate limited amounts of energy using resistive damper systems during “negative energy” tasks like sit-down. Consequently, users are forced to over-compensate with their upper body, residual hip, and intact leg. In contrast, powered prosthetic joints are controlled by motors, which can produce higher levels of resistance at a larger range of joint positions than passive damper systems.  In this study, we found that a powered knee-ankle prosthesis significantly improved weight-bearing symmetry during sit-down compared to passive prostheses. However, we did not observe a corresponding decrease in intact-limb muscle effort. These results indicate that powered...

Kuntz Lab paper, “Screw-tip Soft Magnetically Steerable Needles” has been published in the IEEE Transactions on Medical Robotics and Bionics (TMRB) journal....

Lower-limb-powered prostheses can provide users with volitional control of ambulation. To this end, they require a sensing modality that reliably interprets user intention to move. Ultrasound has been shown to have better resolution and specificity than surface EMG. However, this technology has yet to be integrated into lower-limb prostheses. In this paper, we show that A-mode ultrasound sensing can reliably predict the prosthesis walking kinematics of individuals with a transfemoral amputation. Ultrasound features from the residual limb of 9 transfemoral amputee subjects were recorded with A-mode ultrasound during walking with their passive prosthesis. The manuscript is freely available at this...

Torque-sensitive transmissions have emerged as promising solutions to meet this need by significantly increasing actuator efficiency and power density, but their modeling and analysis remain an open research topic. In this paper, we introduce the sensitivity between input displacement and output torque as a key metric to analyze the performance of these complex mechanisms in dynamic tasks. Our results show that sensitivity analysis is a valuable tool for designers to systematically analyze and create transmission systems capable of human-like physical behavior. The manuscript can be downloaded freely at this link: Actuators | Free Full-Text | Analysis and Validation of Sensitivity...