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The approximate path synthesis of four-bar linkages with symmetric coupler curves is presented. This includes the formulation of a polynomial optimization problem, a characterization of the maximum number of critical points, a complete numerical solution by homotopy continuation, and application to the design of straight line generators. Our approach specifies a desired curve and finds several optimal four-bar linkages with a coupler trace that approximates it. The objective posed simultaneously enforces kinematic accuracy, loop closure, and leads to polynomial first order necessary conditions with a structure that remains the same for any desired trace leading to a generalized result. Ground pivot locations are set as chosen parameters, and it is shown that the objective has a maximum of 73 critical points. The theoretical work is applied to the design of straight line paths. Parameter homotopy runs are executed for 1440 different choices of ground pivots for a thorough exploration. These computations found the expected linkages, namely, Watt, Evans, Roberts, Chebyshev, and other previously unreported linkages which are organized into a 2D atlas using the UMAP algorithm.
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Exploration of Venus’ Upper Atmosphere Using an Aqua and Bacteria Inspired Aerial System
This paper aims to design a jellyfish-inspired robot for the exploration of Venus’ atmosphere. Venus’ hostile environment necessitates different methods for planetary analysis than that of Mars or Earth. In this research, an established jellyfish-inspired drone design is modified to take advantage of Venus’ dense atmosphere for the purpose of upper atmospheric exploration. The original design uses modified Stephenson-I 6-Bar linkages to actuate a soft skin to produce thrust in a fluid, similar to the movement of a jellyfish’s bell; this research compares the original actuator design to 3 new designs based on the 6-Bar and 4-Bar linkages. In addition, a Crank mechanism to change the profile of the balloon is proposed, and the resulting effect on the drag force is compared between the original spherical profile and the modified oblong profile. These mechanisms will allow the robot to maximize its operational time in Venus’s atmosphere. In combination with the design of the jellyfish-inspired robot is the proposal of flagellate-inspired robots that rely on Venus's strong winds to power its host of sensors.
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- Award ID(s):
- 1757793
- PAR ID:
- 10382427
- Date Published:
- Journal Name:
- AIAA SCITECH 2022 Forum
- Page Range / eLocation ID:
- 2581
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.2514/6.2022-2581
