Sensing and Control for Robotic Fish Locomotion
Richard Mason, Joel Burdick

We are studying issues in fluid mechanics, nonlinear control, and sensing that are necessary for the development of self-propelled robot fish. (full report)

Set-Valued Analysis for Switching Systems
Todd Murphey, Joel W. Burdick

Conventional nonholonomic motion planning and control theories do not directly apply to "overconstrained vehicles,'' such as the Sojourner vehicle of the Mars Pathfinder mission. This research investigates some basic issues that are necessary to build a motion planning and control framework for this potentially important class of mobile robots. A power dissipation approach is used to model the governing equations of overconstrained vehicles that move quasi-statically. These equations are shown to be switched hybrid systems. Standard notions, such as the Lie bracket, are extended to these switched systems. We then develop a controllability test for such systems. We explore motion planning primitives in the context of simplified examples. Another application area is that of distributed manipulation, where parts are being oriented by a large array of actuators. Here, too, the issues of discrete behavior as the part traverses different contact states plays a large role in analyzing stability. (full report)

Actuated Surgical Endoscopes for Minimally Invasive Surgery
Hans D. Hoeg, Joel W. Burdick, A. B. Slatkin

Our effort is aimed at developing articulated surgical endoscopes that can access the interior of the human body in a minimally invasive manner for the purposes of visualization, diagnosis and therapeutic intervention. We have specifically focused on design and construction of scopes for use in brain surgery and gastrointestinal procedures. (full report)

Toward Prosthetic Systems Controlled by Parietal Cortex
Krishna Shenoy, Sohaib Kureshi, Richard Andersen, Shiyan Cao, Joel W. Burdick

At present there are no satisfactory treatments or assistive aids for people suffering from neurological disorders such as stroke, ALS, or spinal cord injuries. Neuroscientists have taken great strides in the past few decades toward uncovering basic principles underlying our ability to see and move. The combination of these discoveries and the revolutionary advances in computer technology have led to an emerging view that neural prosthetics --- or electronic interfaces with the brain --- may one day be possible. This project aims to demonstrate the potential for neural prosthetics to help patients with upper spinal cord injury, which results in the loss of arm movements. Andersen and colleagues recently discovered a cortical area in monkeys and humans that encodes the next intended arm movement. This area is ideally suited to provide high-level control signals for guiding real or prosthetic arms. We propose to implant chronic electrode arrays in this region of monkey cortex and to record neural activity generated during reaching arm movements. We will process these neural signals in real-time to construct control signals for guiding a prosthetic arm. Combining behaving-monkey electrophysiology techniques, state-of-the-art electrode array technology, and feedback control systems should provide the foundation on which to build neural prosthetics for humans. Below we outline our major aims and, in the achievements section, we describe our progress in the past year. (full report)