Haptic Feedback System for a Virtual Environment ECE 4902 | Team - - PowerPoint PPT Presentation

Haptic Feedback System for a Virtual Environment

ECE 4902 | Team 1820 | Spring 2018

Project Sponsor: Professor Steven Harrison - University of Connecticut Psychology Department

Team 1820:

Derrick Chen (CompE), Benjamin Marcotte (EE) Ethan Freund (EE), Meridith Kuperstein (CSE/EE)

Advisor:

Professor Shengli Zhou

Outline

• Overview of Project
• Requirements
• Hardware Design
• Programming Design
• Cost Breakdown

Haptic Feedback Systems

“...Of or relating to tactile sensations and the sense of touch as a method of interacting with computers and electronic devices: smartphones that incorporate haptic feedback [1].”

[1] http://www.dictionary.com/browse/haptic

Overview of Project

• Professor Steven Harrison studies human-object interaction, and wants a 1D

linear motion haptic feedback system

• The linear motion system will allow users to simulate frictional forces, and other

forces, while pushing real physical blocks in one dimension and will interact with virtual environments, which they can see projected on a screen

• This system will be used to study how people interact and adapt their motion in

novel, simulated environments with touch feedback

Linear Motion Haptic Feedback System

Virtual Environment Projection Force Feedback Will be able to simulate interactions with springs, different surface coefficients of friction, and virtual walls.

Requirements

• Must handle loads up to 150N
• Feedback delay must be <10ms, or small enough that delay is

unnoticeable

• Must have minimal audible noise
• Must have built in safety features
• Must have two blocks that can move either independently of

each other or concurrently

Design Overview

Belt-Driven Motor Braking System

Motor Force Sensor Motor Controller Circuit CPU Sliding Block F_applied (hand) F_applied (motor) Applied motor torque DAQ Encoder

Design: Rail

• 2 meters: PBC AAE Linear Rail
• Precision Rail Extrusion
• Channels for timing belts

Design: Motors

• AC Servo Motors: Kollmorgen AKM42H-EKDNCA00
• Max Torque: 3.5 Nm
• Provides Position and Velocity Feedback

• To Ensure Minimal Audible Noise, using UMHW

Design: Wheels

Foam Covered Guards Block for User Interaction Insulating Layers Force Sensor Wheels

Carriage Design

a

Aluminum Block Shaft Bearings Pulley Base

System Design

System Design

Carriage and Motor Design

Programming: Requirements

• Multithreading

○ Parallel processes ○ Enough processing power ○ E.g. visual & calculation processes

• Instantaneous data storage to RAM between processes

○ Smaller delay

• On termination of system, save all data to text file.

Programming: Features

• Multithreading for sampling and calculations

○ Maximum of 20 full powered threads

• Wall and spring implementation
• Safety features
• Variable friction negation

Programming: Wall

• Position

○ Cart location w/r to both physical and virtual walls

• Change in time

○ Velocity

• Block movement, with relevant subcases

○ Safety slowdown at 2.5 cm from the wall ○ Wall maintenance

Programming: Visualization

C++ using OpenGL

Programming: Visualization Approach

• OpenGL runs on a separate thread

○ Calls public function that reads DAQ

• Reads DAQ and updates vertices of block based on the display frequency

○ Readings are absolute position ○ 200 cm from 0V - 10V ○ 20 cm/V

Cost Projection

Item Cost ($) Test budget 200 Rail Mount System 350 Motor System 4000 Computing System, DAQ, F/T Sensors 0 (Readily Available) System Machining & Misc. Part Ordering 700 Total 5250

Current Status Completed Tasks Tasks To Do

• Hardware Designed in CAD
• Hardware Assembled
• Completed Real Time

Animation/Projection

• Programming for reading

and controlling Motor, DAQ, and Force/Torque Sensor

• Create ‘Wall’ haptic

feedback simulation

• Create User Manual
• Integrate Safety Features

Questions?