Projects
ANATOMICALLY CORRECT TESTBED (ACT) ROBOTIC HAND MECHANISMS AND CONTROL
The Anatomically Correct Testbed (ACT) Hand has been under construction for several years. Its purpose is to discover mechanisms and control salient features in human hands that allow robust, versatile, dexterous movements and rich object/world exploration. Currently these human hand’s structural and functional features are being uncovered using cadaveric and computational models that are difficult to emulate realistic object interactions. An anatomical robotic tool will allow advancement in biomechanics and neuroscience as well as for current prosthetic, industrial, and personal assistance robotic hand design and control.
↑ Back to TopLIFE-SIZE SAFE BRAKE-ACTUATED MANIPULATOR FOR REHABILITATION, EXERCISE, AND REALISTIC HAPTIC DISPLAY
If a dissipative physical human-robot interaction (pHRI) device can produce the transparency and controllability of an active device, it would dramatically change the safety of such interactions. A 2m^3 workspace (life-size) brake-actuated manipulator (BAM) is developed with sophisticated controllers that utilizes human neural and perceptual science findings.
↑ Back to TopDISTORTED FEEDBACK ROBOTIC REHABILITATION
A robotic rehabilitation environment with distorted feedback introduces an undisclosed discrepancy between the actual movement and the virtual fisual feedback subjects receive about their movement. Feedback distortion targets individuals with chronic stroke, traumatic brain injury, and others with mobility difficulties who have capacity to make functional improvements but may have self0imposed limits on their performance due to entrenched habits , learned-non-use, or psychological barriers. Our study has shown that the finger’s range of motion can increase by more than 50%, spasticity measure to be reduced, and functional scores (such as AMAT score) to improve from a 6-week therapy for subjects 2-8 years post injury.
↑ Back to TopHUMAN HAND NEUROMUSCULAR STRUCTURE AND CONTROL
Human psychophysical experiments are conducted to understand neuromuscular control of the hand. We record EMGs, joint angles, forces, and stiffness from subjects to understand what humans optimize as they select a neural control strategy from redundant/overactuated structure. In addition, Constructing and controlling the ACT hand has resulted in further understanding about the tendon shapes and routing, bone shapes, non-linear moment arms, and neural control optimization.
↑ Back to TopCHARACTERIZATION OF MULTI-FINDER TWISTING MOTION
In order to work on diagnostic and rehabilitation paradigms for dexterous finger movements, the finger coordination strategies must be understood. Twist-cap motion is chosen as a simple multi-finger coordinated movement to study. We characterize hand movements from subjects who are healthy (younger and elderly) and those who have difficulty producing these movements.
↑ Back to TopCORTICAL CONTROL OF PROSTHETIC HAND (in collaboration with Andrew Schwartz)
With population coding strategy, arm movement can be specified in a three dimensional space. This project addresses the next step to allow orienting the hand and manipulating objects such as a twist cap with multiple fingers.
↑ Back to TopREVERSE-ENGINEERING THE HUMAN BRAIN’S ABILITY TO CONTROL THE HAND (in collaboration with Francisco Valero-Cuevas and Emo Todorov)
In collaboration with USC, we record hand-object interactions and neuromuscular activity during real-world manipulation tasks; use the experimental data to approximately infer the underlying sensorimotor control laws; refine these control laws in physically realistic simulations via optimal control methods; implement, test and adapt them on the ACT hand; and use the engineering insights obtained from the synthetic system to better understand its biological counterpart.
↑ Back to Top