Model-based design and control of deformable robots and haptic devices

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Abstract/Contents

Abstract
Haptic interfaces are used in training, guidance, and teleoperation to provide force and tactile feedback to a user from a virtual or remote environment. In contrast to the rigid components typically comprising haptic devices, compliant materials could enable new haptic devices that move via deformation rather than via joints. However, the design and control of devices consisting of soft or deformable components is challenging, due to the complex coupling between actuation and end-effector motion and due to a lack of sensing. This thesis considers the potential for computational model-based methods to address challenges in the design and control of deformable haptic devices. In the first half of this thesis, we introduce a new haptic shape display made of soft materials for organ simulation for medical training. The device is a continuous, fully 3D shape-changing surface that a user can touch and hold. We develop a mass-spring model of the device that allows us to understand how different pneumatic actuators affect the shape. Further, we develop an automated design algorithm based on a heuristic controller and a simulation of the device to determine how to arrange a limited number of actuators to reproduce target shapes. This device and its associated algorithms show how a model can be used to understand complex deformations due to pneumatic actuation of a compliant system. The second half of this thesis focuses on the precise control of deformable haptic devices. Two deformable kinesthetic haptic devices are introduced: a 2-DOF planar device and a 5-DOF device. In these devices, forces are transmitted from the actuators to the user via deformable transmissions which allow for easy fabrication and reduced mass and friction in the device. Using these devices, we demonstrate methods for design, sensing, and control. We derive a general formula for the mapping of actuator stiffness to end-effector stiffness and verify it using the planar device. For sensing, we present results in model-based sensing using only actuator information or using model-calibrated embedded sensors. With these techniques, we can use the deformation of the device to measure the force applied to the device without an external force sensor. We extend techniques from rigid robot workspace analysis to deformable robots. Finally, we develop control techniques for haptic rendering which compensate for device mechanics and characterize the resulting forces. Together, these results in design and control show that model-based methods can overcome some of the challenges of deformable devices to enable new haptic interfaces

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 Koehler, Margaret Irene Schatz
Degree supervisor Okamura, Allison
Thesis advisor Okamura, Allison
Thesis advisor Duriez, Christian
Thesis advisor Khatib, Oussama
Degree committee member Duriez, Christian
Degree committee member Khatib, Oussama
Associated with Stanford University, Department of Mechanical Engineering.

Subjects

Genre Theses
Genre Text

Bibliographic information

Statement of responsibility Margaret Koehler
Note Submitted to the Department of Mechanical Engineering
Thesis Thesis Ph.D. Stanford University 2020
Location electronic resource

Access conditions

Copyright
© 2020 by Margaret Irene Schatz Koehler
License
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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