Research Interests

Extravehicular Activity (EVA) Research

Modeling the dynamics of human performance: To develop the computational capabilities to accurately model the complete integrated dynamic system preflight (e.g., astronaut, Orbiter, remote manipulator arm, and a spinning satellite). Quantitative analysis of humans performing extravehicular activity (EVA) and intravehicular activity (IVA) is investigated through inverse dynamics, Lagrangian techniques, and Kane’s theory of dynamics.

Dynamics and Control of Astronaut Motion

Adaptive physiological control: Engineering control theory is applied to human physiological systems. Characterization of dynamic motion control strategies is quantified through hierarchical control strategies, vestibular and proprioceptive feedback, and musculoskeletal impedance control. Insight into adaptive mechanisms operating on these motor programs is gained by focusing in particular on the changes in control strategies resulting from exposure to microgravity. Studies include pre- and post-flight astronaut jumping performance and novel false platform experiments where subjects “fall through the floor” to elicit preprogrammed motor control strategies.

Locomotion Modeling And Orthoses

The objective of this project is to build walking assistive devices for the physically handicapped by combining a deep understanding of the mechanism of walking, the physiology of the human body and engineering insight. This project began with the goal of building a Powered Assistive Walking Device for Paraplegics. This device would be inconspicuously mounted on a paraplegic and have compact actuators with an adaptive control system that would allow them to walk extended periods of time. There is an extensive background of assistive walkers.

Space Flight Experiments

The Enhanced Dynamic Load Sensors (EDLS) experiment flew on board the Russian MIR space station. Investigation of the dynamic response inside the spacecraft/vehicle including disturbances by crewmembers and investigations of the fundamental consequences of microgravity on living organisms during space flight. Engineering analysis, hardware design, and ground-based scientific studies precede flight opportunities. The Dynamic Load Sensors (DLS) spaceflight experiment investigated astronaut crew disturbance to the microgravity environment as measured by crew-induced loads in the middeck of the Space Shuttle. Follow-on experiments might include mitigation devices as well as an assessment of crew force measurements during Shuttle/MIR flights. The Mental Workload and Performance Experiment (MWPE) flew on Space Shuttle Mission STS-42 and assessed astronaut short term memory, motor control, and ergonomics in space.

Computer Simulation and Animation

Mathematical programming for analytical models that simulate in-space operations and activities. Developing 3-D visualization and animation packages for the dynamics and control research efforts. All computer simulations are verified with experimental data. Future efforts may include haptic input devices and virtual reality technologies to enhance the computer simulations.