Spring 2012
Phillip Daniel
Overview
Built a hardware platform to study the mechanical efficiency, speed and maneuverability of Thunniform swimmers.
Responsibility
Loads on the machine during constant speed swimming were estimated using Lighthill’s elongated body theory and the template kinematics of the swimming profile are based on work done by Barrett in “The Design of a Flexible Hull Undersea Vehicle Propelled by an Oscillating Foil.” The machine is designed to keep the inertia of each tail segment minimal to maximize the mechanical efficiency of the device. The components of the body are also laid out so that the center of buoyancy and center of gravity are nearly coincident, as with biological swimmers. Actuators were optimized based on the swimming loads, inertial properties of the structure, and efficiency of the gearboxes. A thermal model was used to ensure that any generated heat could be dissipated.
Spring 13-15
Spring 2012
Overview
I worked in a small team to design and build a medium-duty desk with an easy to adjust position and orientation. The primary goal was to rigidly support the weight of a laptop and forces from user interaction, such as leaning and typing, while remaining continuously repositionable in a plane.
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Skills Learned
I learned how to design and document tests, operate an Instron force testing machine, fabricate parts to within specified tolerances, model the stiffness of assemblies, trouble shoot mechanical assemblies, and model the interactions between deformable bodies in Matlab/use numerical analysis to inform design decisions.
Overview
I worked with Professor Sangbae Kim to design a modular foot with an integrated pressure sensor, for the lab's biomimetic cheetah robot. The phase of the robot's running gate is determined by torque feedback from the joint motors. However, this data has noise in it because of the joint inertia. To allow for an accurate determination of running phase, the sensor told the controller if a leg was in contact with the ground.
Outcome
A foot was successfully integrated into the robot and allowed for the gate phase to be more accurately determined. The high viscosity of one of the compliant polymers in the foot lead to a contact measurement that was true after the foot left the ground, for a fraction of a second. The next step is to change the design of the sensor so that the foot keeps the desired compliance without a detrimental time delay of the measurement, which leads to a limited bandwidth of the controller.