Takeoff and landing in birds as a source of inspiration for designing aerial robots
Abstract/Contents
- Abstract
- Perching can enable small flying robots to extend their battery life and raises opportunities for a diverse set of tasks including exploration, inspection, and collection of samples. However, these robots are currently limited in their reliability and usefulness when interacting with objects in natural environments. On the other hand, birds make interactions in unstructured environments with apparent ease, in particular taking off and landing on a wide range of complex surfaces, including trees. To understand how, we studied takeoffs and landings made by Pacific parrotlets from instrumented perches ranging in diameter and surface texture. Across all perches, these birds employ stereotyped takeoff behaviors that enable them to simultaneously detach their feet while generating the impulse needed to initiate flight. They crouch and then extend their legs to push off, directing peak forces at a consistent angle relative to the perch. Meanwhile, they peel their feet from the surface starting from the rear toes. During landing, the parrotlets exhibit stereotyped leg and wing dynamics regardless of perch diameter and texture, but foot, toe, and claw kinematics become surface-specific upon touchdown. A new grasping model, which integrates our detailed measurements, reveals how birds stabilize their grasp. They combine predictable toe pad friction with probabilistic friction from their claws, which they drag to find surface asperities—dragging further when they can squeeze less. Synthesizing the learnings from the birds, we developed a bird-inspired bipedal robot that can dynamically perch on complex surfaces. Like birds, the robot employs a stereotyped set of behaviors for robustly handling varied surface geometries and textures, such as tree branches. The robot's two legs enable independent passive energy absorption responses to accommodate variable surface geometry. The underactuated grasping mechanism wraps around irregularly shaped objects in less than 20 ms and employs a bird-inspired release technique that can detach from objects consistently. A tendon differential allows the toes to share loads under elastic tension, and the tendon-driven claws scrape over the surface to find viable asperities. Closed-loop balance control increases the range of states, including kinematics, hardware design, and behavior, over which the robot can land, which we term the sufficiency region. This platform can be used not only to study how and why birds take off and land the way they do, but also for biological and environmental studies.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2020; ©2020 |
| Publication date | 2020; 2020 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Roderick, William Robert Thomas |
|---|---|
| Degree supervisor | Cutkosky, Mark R |
| Degree supervisor | Lentink, David, 1975- |
| Thesis advisor | Cutkosky, Mark R |
| Thesis advisor | Lentink, David, 1975- |
| Thesis advisor | Follmer, Sean |
| Degree committee member | Follmer, Sean |
| Associated with | Stanford University, Department of Mechanical Engineering. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | William Robert Thomas Roderick. |
|---|---|
| Note | Submitted to the Department of Mechanical Engineering. |
| Thesis | Thesis Ph.D. Stanford University 2020. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2020 by William Robert Thomas Roderick
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