Design and analysis of a discrete angular joint for use in digital robotic systems
Abstract
Research into discrete actuation for robotic systems has led to the creation of smaller, more efficient means of manipulation than continuous joints. Suggested uses for such robots include pick and place operations, positioning within a grid system, and uses where hyper-redundancy leads to a large workspace even with discrete movements. Discrete or binary actuations offer accurate and repeatable positioning without the need for control loops that traditional manipulators necessitate. Three primary achievements are accomplished in this research. The first contribution is the design, analysis, and prototyping of a three position mechanism for use in digital robotic systems. The mechanism relies on linear translation and a pin in slot connection to provide three angular output positions: a nominal position of 0° and two equal angular displacements. Full kinematic and static force analyses are outlined and sample results are given. The design has infinite mechanical advantage in all three output positions. The prototype is discussed and compares favorably with a previously designed mechanism used as a benchmark. The second contribution is the design and analysis of an angular three position mechanism capable of cyclical motion. As in the linear design, the mechanism uses a pin in slot connection and provides three angular output positions: a nominal position of 0° and two equal angular displacements. Unlike the linear mechanism, the angular mechanism relies on angular motion driven by linear input and can actuate from any output position to either of the two remaining output positions. Full kinematic and static force analyses are outlined and sample results are given. The angular mechanism also has infinite mechanical advantage in all three output positions. The third contribution is the presentation of a novel mechanism that uses repeated linear motions to drive an intermittent angular device. This mechanism is the modified Geneva drive, so named because it is similar to a Geneva drive. A kinematic analysis is included and several design alternatives are outlined.
Degree
M.S.M.E.
Advisors
Cipra, Purdue University.
Subject Area
Mechanical engineering|Robotics
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