Wireless Assistive Control System

Wireless Assistive Control System

Project leader: Benjamin Danziger, EETodd Bentley, ISEJim Corcoran, CEJay Radhakrishnan, EEPeter Drexel, EEVianna Mullar, EE

Video

AgendaProject Overview

• Customer Requirements• System Architecture

Design Summary• Front End• Strap• Bioradio• Testing

• Signal Processing• RC vehicleBudget

Scheduling

Future Improvements

Final Summary

Project Criteria Mission: Prove a control system can model bio-

signals

Goal: Design an interactive proof of concept that prospective students can use at open houses

Purpose: show off the Biomedical Engineering Option

Must be safe and robust!

Commissioned by the Electrical Engineering Department

Project Overview

RC Vehicle controlled by Electromyographic (EMG) signals

Convert surface EMG signals from human muscle to computer commands

Send commands wirelessly to an RC Vehicle

Customer Requirements Strap

Eliminate movement artifact/transients/noise Simplify electrode application

Signal Processing Properly distinguish between the muscle groups Robust Control Algorithm Wireless Output

RC Vehicle Bio-signals must control the vehicle's

movements Visual and Audible feedback

System Architecture

Filter

Control System

USB

RF Transmitter

RF ReceiverMicroProcessor

DC Motor (Forwards/Backwar

ds)DC Motor

(Left Right)

Lights

Audio

Right Bicep

Right Thenar

Left Bicep

Left Thenar

BioRadio

150 TX

BioRadio

150 RX

Design Summary: Front End

Strap Design Originally wanted glove-like design Infeasible – 25 dimensions on human

hand and arm Anthropometric Design

Adjustable from 5th thru 95th percentile body types.

Expedites application of EMG sensors. Nylon material construction

Incredibly durable Nylon tubing hides wires and prevents

movements

Design Summary: Front End

EMGs Non-invasive, uses surface

electrodes

Institute Review Board (IRB) Need approval for human testing

Use of BioRadio Collects up to 8 bio-signal channels

(we’re using 4) Safely collects all data Transmits the data wirelessly

Data Acquisition Testing

0 1 2 3 4 5 6 7 8 9 10-0.5

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

time (s)

volta

ge (v

)

Cross talk with movement B

Muscle A

Muscle B

• Acquired data from 5 males and 5 females• Recorded Body Mass Index (BMI)

• Tested Normal Weight, Overweight and Obese

• Asked if they went to the gym• Ensured action could be

performed and recorded by BioRadio150 on all individuals

• Observe Crosstalk• Tested strap• Confirmed EMG frequency

range• Fatigue Factor

Design Summary: Signal Processing

Custom Moving Average

Filter

Normalization(Finds max

value)

Difference(Forward-Reverse)

(Right-Left)

Level Coding

All on or

All off

Data Packet

Customer Requirements met:•Channels distinguished•EMG based algorithm•Wireless output

Design Summary: RC Vehicle Receives commands by an RF Receiver

Powered by 6 NiMH AA batteries

Uses a ATtiny2313 Microprocessor

Uses two DC motors (one for turning, one for acceleration), each with its own H-bridge

Visual Feedback: Uses LED system

Audible Feedback: ChipCorder IC is used to play different sound effects correlating to the user’s actions

Design Summary: RC Vehicle

Light Scheme on RC Car

Full System Testing

Live System Tests Used all members of the team and

several IRB participants

Ensured all 4 commands were functional

Drove car around the Wetlab

Budget

Final expenditure is $411.32

Initial cost was $339.59

Does not include the BioRadio

Budget~ $1000

Schedule•Strap prototyping completed end of week 5

•Had motion and control end of week 7, preliminary demo for customer

•IRB testing completed end of week 9

•Final construction of RC car prototype by week 10

Difficulties and Future Improvements

Future Improvements: Electrode Pairs Implement DSP Use servo instead of DC motor RC Vehicle with sharper turning radius

Difficulties: Obtaining a clean signal Parallel processing in “Real time”

Final Summary

Meets all Customer Requirements

Within budget Cost= $411.32 Budget~ $1000

We will let YOU determine if it’s a success.

Questions?

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