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ME Dissertation Defense: Melisa Orta Martinez

August 22, 2019 - 11:00am to 1:00pm
Building 520, Room 131

Free

Design and Analysis of Open-Source Haptic Devices for Educational Applications

Open-source hardware significantly impacts the development of technology by allowing communities of users with varied expertise to share, customize and collectively improve on designs. Most haptic hardware available outside of the research community is proprietary and expensive. This prevents communities of users from easily obtaining, building, modifying, and learning from the devices. We propose that the ability to easily obtain, assemble and customize a haptic device is especially important for educational applications. In this work we present three open-source haptic devices, for which we carefully considered trade-offs in cost, ease of making, and performance -- toward making haptic devices more accessible for educational applications.

We first present Hapkit 3.0: an open-source, customizable, 3D printed, 1-DOF, kinesthetic haptic device developed for science, engineering and math learning. We performed an analysis of the mechanical components of the Hapkit family of devices, which includes two previous versions of the device. In order to understand the ability of the family of Hapkit devices to render mechanical properties in virtual environments, we performed a stiffness discrimination study in which we found that Hapkit 3.0 outperformed the previous two versions. We then discuss the use of the Hapkit family of devices in several educational environments: a middle school classroom, an online class, and undergraduate and graduate courses. We also investigated the use of Hapkit to illustrate abstract mathematical concepts for high school students, and found evidence that haptics could be used to display mathematical functions.

We then present Haplink: an open-source, 3D printed, kinesthetic haptic device that can be used as a 1- or 2-DOF device and where the kinematics of the 2-DOF device build on the kinematics of the 1-DOF device. Haplink was designed with the idea that students will benefit from learning concepts incrementally, and that a device that itself increments from one to two degrees of freedom using a simple mechanism will aid in this process. We analyze the resolution and force capabilities of Haplink throughout its workspace and present guidelines to render different virtual environments. We also describe the use of Haplink in a college freshman course on haptics, where we found benefits to teaching concepts incrementally.

Finally, we present HapCaps: an open-source, 3D printed, tactile haptic device for finger sense training. HapCaps are haptic buttons designed to sense a press and give a tactile cue in the form of a vibration. We used 10 HapCaps to build a system used in a four-week pilot study where first graders performed finger training at the same time as they were learning math. The purpose of the experiment was to evaluate our device in a classroom environment as well as understand the logistics of using the HapCaps hardware in a school setting. At the same time, we looked for any interesting educational results that would emerge from a short study. Design improvements were made based on the results of the study, and we found strong evidence that the HapCaps system can be used to improve finger perception.

Event Sponsor: 
Design Group, Mechanical Engineering
Contact Email: 
cofferb@stanford.edu
Contact Phone: 
650-725-9131