MODIFICATION OF A GEARBOX GO-KART TO ALLOW FOR FULL HAND CONTROL OPERATIONFinal Year Report PresentationBy: James King

PROJECT BACKGROUND

Project Introduction Physically impaired drivers struggle to continue driving their

vehicle without hampering comfort, ergonomics and safety. In a competitive situation (such as shifter karting), these factors could affect driver competitiveness and safety.

Subjects Drawn Upon 3D CAD Modelling Technical Communications

PROJECT OBJECTIVES

Project Objectives Research available human motions Determine optimum motion for each control Determine optimum method to actuate controls (How?) Generate and Evaluate concept ideas Generate 3D model of final concept design

SOURCES

Assistive Technology Partners (2011) Adaptive driving for persons with physical limitations

Case, K., Porter, M., Gyi, D., Marshall, R. and Oliver, R. (2001) Virtual fitting trials in ‘design for all’. Journal of Materials Processing Technology. [Online] Vol.117 (s 1–2), pp.255–261.

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Dols, J. F., García, M. and Sotos, J. J. (2014) Procedure for improving the ergonomic design of driving positions adapted for handicapped people. [Online] Vol.12.

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on traffic flow theory [Online]. Gyi, D. ., Sims, R. ., Porter, J. ., Marshall, R. and Case, K. (2004)

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Kong, Y.-K., Kim, D.-M., Lee, K.-S. and Jung, M.-C. (2012) Comparison of comfort, discomfort, and continuum ratings of force levels and hand regions during gripping exertions. Applied Ergonomics. [Online] Vol.43 (2), pp.283–289.

Koppa, R., J., McDermott Jr., M., Raab, C. and Sexton, D., J. (1980) HUMAN FACTORS ANALYSIS OF AUTOMOTIVE ADAPTIVE EQUIPMENT FOR DISABLED DRIVERS.

SOURCES Lawton, C., Cook, S., May, A., Clemo, K. and Brown, S. (2008) Postural support

strategies of disabled drivers and the effectiveness of postural support aids. Applied Ergonomics. Vol.39 (1), pp.47 – 55.

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SOURCES Reed, M. R., Manary, M. A., Flannagan, C. A. C. and

Schneider, L. W. (2000) Effects of vehicle interior geometry and Anthropometric variables on automobile driving posture. Human Factors. [Online] Vol.42 (4), pp.541–552.

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The Motor Sports Association (2015) The MSA Yearbook 2016 [Online]. Staines, Middlesex: The Royal Automobile Club Motor Sports Association Ltd.

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MAIN FINDINGS Anthropometrics and Ergonomics are

key Drivers often shift position under

braking/ cornering Forces acting on driver due to

cornering and braking Accelerator should not be actuated

using push motion Available forces of different human

motions (Right) Forces required to actuate different

controls systems

PRIMARY RESEARCH

EXISTING DESIGN

Accelerator and Brake Clutch and Gear Change

DESIGN BRIEFHigh End Objective Must allow for driver to actuate all control systems without

removing hands from wheel.Product Design Specification Survive in track environment with max. vibration frequency of

Approximately 10hz Must adhere to MSA (Motor Sport Association) safety and

technical regulations (Section H and Section J) Remove requirement for driver to take hand off steering wheel

DESIGN BRIEF Accelerator – precise, accurate activation

with max. force 25N Brake – precise, accurate activation, safe

with max. force 200N Clutch – only required ONCE, max. force

100N Gear Change – Driver can quickly and

comfortable change gear within 0.1 seconds Installation – Quickly and easily, Clamp

onto steering column Maintenance – Easy to maintain on the

move

DESIGN EXERCISE

ANALYSIS OF MOTIONS AND FORCES

► Analysing data from tables collected from Federal Aviation Authority (2008)

► Determining Optimum Elbow Flexion position (CEM Table)

► Determining optimum actuation motion for each control sub-system:

► Accelerator► Brake► Clutch► Gears

ELBOW FLEXION ANALYSIS

► Concept Evaluation Matrix Table► Looked at:

► Forces Available► Practicality and Comfort► Ergonomics with wheel

► 150 Degrees deemed optimum► Closest to natural driving position (Right)

ACCELERATOR MOTION SELECTION

Maximum Force 25N Requires accurate motion for

actuation All motions capable of force

requirement Pull, Push and Grip better

Ergonomically

BRAKE MOTION SELECTION

Maximum Force 200N Only Pull, Push and Grip motions

get close to force. Pull and Grip motions again

more ergonomic Grip motion selected for use

in final concept design

CLUTCH MOTION SELECTION

Maximum Force 100N Pull, Push and Grip motions best

to actuate Most comfortable and

ergonomic for driver Grip Motion selected for use

GEAR CHANGE SELECTION Current gear change system requires driver to remove hand from

wheel May result in driver instability, affecting drive and safety Ideal system removes this requirementIdeas Proposed

Push Button Flappy Paddle Bicycle Gear Change

Problems Uncertainty around rules, system would need to be verified by

MSA Karting governing body.

CONCEPT GENERATION

CONCEPT 1 – TRIGGER THROTTLE

Uses motorcycle brake system with master cylinder

Modified brake lever for better ergonomics/ comfort

Trigger fly-by-wire throttle located at top of brake lever using RC servo system

Problems Fingers joined by same muscle, no independent

movement (Right)

CONCEPT 2 – 2 PADDLE DESIGN Uses 2 levers to actuate accelerator and brake

sub-systems Same braking system (motorcycle brake), modified

handle Accelerator lever fly-by-wire system using RC

servoProblems 2 paddles require slight hand position adjustment

from one to the other

CONCEPT 3 – THUMB THROTTLE

Fly-by-wire thumb throttle using RC servo Thumb motion works independently from fingers

(Below Right) Allows neater control packaging space Suitable for use in final concept

CONCEPT 4 – BICYCLE BRAKE CLUTCH

Clutch only required ONCE, during get away Use bicycle brake lever to actuate Mount to back of steering wheel Once released, moves out of wayProblems Doesn’t allow for tidy package with other controls

CONCEPT 5 – GRIP LEVER CLUTCH

Motorcycle brake lever system (similar to brake sub-system)

Allows for neater product design package Suitable for use in final design package

FINAL CONCEPT DESIGN MODEL

FINAL DESIGN CONCEPT

Accelerator sub-system – Thumb throttle, fly-by-wire servo system

Brake sub-system – Motorcycle brake lever (modified handle)

Clutch sub-system – Motorcycle brake lever (modified handle)

Gear change sub-system – Electronic push button system (would require verification)

MODEL OF FINAL CONCEPT DESIGN

PROJECT LIMITATIONS

Ambiguity around gear change regulations Design layout due to Internet source model Limitation in references on subject

CONCLUSION Aim was to design an alternative control system for a gear

shift Go-Kart. This was achieved by:

Analysing available forces from human motions Determining which motions are suited for each control Identifying the optimum control actuation method Generate and analyse concepts Create final concept design

FUTURE WORK

Optimising package size Clearer understanding of gear change rules Look into linkages between controls and systems Look into materials and manufacture of parts Build and test prototype in controlled environment

Test for Functionality and Safety

THANK YOU FOR LISTENINGAny Questions?