Exploiting contact dynamics for grasping and anchoring in the field

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This thesis is about how to equip robotic platforms with the capability to forcefully interact with their environments. These forceful interactions often entail designing grippers or end-effectors that can grasp or anchor to different environmental features. When designing these grippers, the general design approach has four common considerations. The first is the contact dynamics, where the gripper interacts with the surface. This includes both the contact mechanics at the surface and the dynamics caused by the interaction. The second is how to achieve the desired surface conformity between the gripper and the often irregular contact surface. The third is the incorporation of load sharing elements to uniformly distribute the interaction force across the contact area, especially in the case where astrictive contact dynamics are used. Last, we consider how the integrated system should respond to the dynamic interaction to achieve the desired system response. In this thesis, we present three different mobile robots intended for operations in the field with forceful interaction. Although they are different platforms, the design approach of their grippers is consistent and can be applied to many other different robotic platforms and field scenarios. The first of these robot platforms is Astrobee, a free-flying robot inside of the International Space Station (ISS). A gripper was designed for Astrobee and allowed it to grasp and perch onto flat surfaces inside of the ISS with gecko-inspired adhesives. The second gripper enabled a quadrotor to capture a flying target. We define a velocity sufficiency region of acceptable initial conditions immediately prior to contact and show that the incorporation of passive mechanisms greatly expands the region. Last, a new climbing robot concept, ReachBot, is designed for interaction with rocky caves. ReachBot is a robot that consists of a small body with long limbs created by extendable booms. We present the system design considerations, a planar prototype, and tests conducted with a partial (single arm) 3D system prototype with a microspine gripper in the Mojave Desert. In these examples, the dynamic interaction results in limits in the force space that must be satisfied to achieve successful grasping. Then, along with the incorporation of passive mechanisms, one can create a sufficiency region of possible initial conditions immediately prior to the contact, with a probability of grasp success. This approach to modeling and passive mechanism design can simplify the control of the robot and inform future design iterations and modifications to meet the requirements of other robotic platforms.


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 2023; ©2023
Publication date 2023; 2023
Issuance monographic
Language English


Author Chen, Anthony Guochenxiao
Degree supervisor Cutkosky, Mark
Thesis advisor Cutkosky, Mark
Thesis advisor Okamura, Allison
Thesis advisor Pavone, Marco
Degree committee member Okamura, Allison
Degree committee member Pavone, Marco
Associated with Stanford University, School of Engineering
Associated with Stanford University, Department of Mechanical Engineering


Genre Theses
Genre Text

Bibliographic information

Statement of responsibility Tony G. Chen.
Note Submitted to the Department of Mechanical Engineering.
Thesis Thesis Ph.D. Stanford University 2023.
Location https://purl.stanford.edu/dy138fm1029

Access conditions

© 2023 by Anthony Guochenxiao Chen
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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