7eor _Tech THE GEORGE W. WOODRUFF SCHOOL OF

MECHANICAL ENGINEERING

Georgia Institute of Technology

Atlanta, Georgia 30332-0405

ME 4182

MECHANICAL DESIGN ENGINEERING

NASA/UNIVERSITY

ADVANCED DESIGN PROGRAM

LUNAR MATERIAL

TRANSPORT VEHICLE

MARCH 1988

Charles D. Fisher

Douglas Lyons

W. Allen Wilkins Jr.

Harry C. Whitehead Jr.

AnEqualEducationand EmploymentOpportunityInstitution

AUnitof the UniversitySystemof Georgia
ABSTRACT

The proposed vehicle, the Lunar Material Transport Vehicle (LMTV), has

a mission objective of efficient lunar soil material transport. The LMTV has

been designed to meet a required set of performance specifications, while

operating under a given set of constraints.

The LMTV is essentially an articulated steering, double-ended dump

truck. The vehicle moves of four wheels and has two identical chassis halves.

Each half consists of a chassis frame, a material bucket, two wheels with

integral curvilinear synchronous motors, a fuel cell and battery arrangement,

and electromechanically actuated dumping mechanism and a powerful

microprocessor. The vehicle, as designed, is capable of transporting up to 200

ft s of material over a one mile round trip per hour. The LMTV is capable of

being operated from a variety of sources. The vehicle has been designed as

simply as possible with attention also given to secondary usage of components.
TABLE OF CONTENTS

PROBLEM STATEMENT

INTRODUCTION

OBJECTIVES

CONSTRAINTS

DESCRIPTION OF LMTV

GENERAL DESIGN CONCEPT

CHASSIS

SOIL BUCKETS

WHEELS

DUMP MECHANISM

MOTORS

STEERING

POWER

BATTERY SOURCE

FUEL CELLS

POWER REQUIREMENTS

CONTROLS

HUMAN FACTORS - TELEOPERATION

CAMERAS

COOLING/HEATING

PRODUCTIVITY

CONCLUSIONS

RECOMlVIENDATIONS

ACKNOWLEDGEMENTS

REFERENCES

APPENDICIES

APPENDIX A - SAMPLE CALCULATIONS

APPENDIX B - VENDOR INFORMATION

APPENDIX C - PROGRESS REPORTS

APPENDIX D - FIGURES

1

2

3

4

5

7

9

10

11

13

14

15

16

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19

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21

22

25

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PROBLEM STATEMENT

INTRODUCTION

The moon was formed approximately 4.6 billion years ago. Until recently,

man has not known the physical characteristics and composition of the surface.

With the U.S.A. Apollo and U.S.S.R Lunar missions, research data has been

retrieved to answer many questions about the properties of the moon.

Research is currently underway to possibly colonize the lunar surface.

Many advantages exist in the possibility of permanent structures and

facilities for research. The combination of the gravitational setting with the

vacuum environment will be capitalized by increased scientific investigation.

The lunar surface can be considered a total vacuum with a pressure of 10E-12

Torr. The surface is lifeless, dry and contains oxygen abundant compounds.

Obstacles exist to construction and human operation on the surface. The

surface soil is similar to sand; therefore, traction and the abrasive

characteristics of the sand-like soil will create problems with any lunar

vehicular machinery. The vehicles will have the same inertia but will be onesixth of the earth weight. This reduction in weight will decrease the traction

of the wheels on the surface. All moving parts must be encased to prevent

damage by abrasive soil contact.

With the possibility of colonizing the lunar surface, a definite need would

exist for the transport of lunar soil and other bulk materials. A suitable

vehicle must be designed, within the following objectives and constraints, for

this purpose.
OBJECTIVES

PERFORMANt_E

SLOPE

The loaded vehicle should be able to perform on a 20% grade.

SPEED

The loaded vehicle should be able to operate in a range of 5-

15 mph.

TRACTION

The vehicle should be designed in order to provide sufficient

traction on the lunar surface.

SELF-RIGHTING

The vehicle must be able to maneuver itself out of all possible

situations.

PRODUCTIVITY

The vehicle should transport 100 cubic feet of soil in each load

or an equivalent weight of 1,800 moon pounds. The vehicle

should transport this load in a 8 minute, 1 mile round trip.

The time will be 6 minutes at 10 mph with 2 minutes for

unloading.

SPECIFICATIONS

GENERAL

The vehicle must be as mechanically simple as possible in order

to ensure maximum reliability.

LOW HORSEPOWER

The loaded vehicle must be able to operate on 5 - 15 hp.
LOWCENTER OF GRAVITY

Due to the 1/6 gravity force on the lunar surface, the center

of gravity must be as low as possible to prevent easy

overturning.

GROSS WEIGHT

The gross weight must be kept to a minimum due to the

extremely high shipping cost.

CONTROL

The operation of the vehicle should be controllable from the

following: a local controller, an earth based controller, and

from the vehicle itself.

SIZE

The following factors will be considered in the determination of

the vehicle size: turning radius, wheel size, bucket capacity,

and overall dimensions.

The vehicle must also fit in the 15 foot wide Space Shuttle

cargo bay.

BRAKING

It is desirable to engage a regenerative braking system.

CONSTRAINTS

GENERAL

BODY

The vehicle must operate on four wheels with two bodies and

two buckets.
BODY PROPORTIONS

The proportion and shape of the wheels to the buckets must

be constant, as it is desirable to have interchangeability with

other proposed lunar devices.

OPERATIONAL

RANGE

The operating range of the vehicle is limited to line-of-sight

due to the transmission characteristics of radio equipment

operating in a vacuum.

TEMPERATURE

The vehicle must be able to withstand extreme temperature

differences (-120°C to +120°C).

ENVIRONMENT

The vehicle must be able to operate in a vacuum.

The vehicle must reliably operate in the highly abrasive lunar

environment.

DESCRIPTION OF LMTV

GENERAL DESIGN CONCEPT

The major components of the LMTV will consist of four wheels, two

identical halves of the chassis frame, two soil buckets and an articulated

steering system (Fig. l). Both chassis frames are in the shape of a tuning

fork. A platform is located in the V- section of the frame. The controls,

fuel supplies and other operational equipment will be located in this V-section

of the chassis halves.
The motors will be located at the connection of the wheels and axles.

The regenerative braking and wheel speed will be a computer controlled

function and will be performed, through controls, at the wheel interface. The

dump mechanism will lie parallel to the inner sides of the fork of the chassis

frame. Articulated steering will be utilized at the connection of the two

chassis halves. The dump mechanisms and the articulated steering devices are

electromagnetic actuators. The steering of the vehicle will be controlled

through the actuators and by varying the speed of each individual wheel. All

mechanisms and computer controls are accessed through the center section

¢omponen ts.

The control devices can be accessed through local remote control or

through teleoperator communications. Visual communications will be the major

source of earth-initiated control. The teleoperator communications will have

the capability of override of on-board computer-originated sensors.

CHASSIS

In formulating the design of the chassis, there were a number of

constraints and objectives that had to be considered. First, the chassis is

required to support the shear forces, torsional forces, and bending moments

that are placed on it by the LMTV components, yet still must remain

lightweight. Secondly, the chassis is designed so that it can be used in other

applications once the mission of the LMTV has been completed. In addition,

the material used to manufacture the chassis has to withstand the harsh lunar

environment.

The final chassis design consists of four rectangular box beams (for each
half of the vehicle) which are made of a fiber composite material. These

beamsare joined by three high strengthaluminum fastenersas shown in Figure

2. This configuration provides a number of advantages. First, the chassisin

its disassembledform is easily transported form earth and can be easily

assembledonce in orbit. Second,the materials used offer substantial weight

reduction with high strength. Third, the four beamsand plates can be usedin

almost limitless applications after the LMTV has reached the end of its

usefulness. The overall dimensionsof the chassisare illustrated in Figure 1.

The fiber compositebeamsare to be synthesizedusing IM6 fibers (High

Modulus Graphite Fibers) with a Polyether-ether-ketone(PEEK) matrix. This

provides a favorable strain to failure ratio, high toughness, and good

repairability. The maximum usable temperature of the beams is 220°C.

Another important advantageto using compositematerial is that the beamscan

bereusedby heating to the "melting" point and reshaping.

Quasi-Isotropic stress-strain characteristics are achieved using by 0°,

+__45 °, and 90° fiber oriented plies. The 0° oriented fibers provide support for

bending stress (in plane stress), the 90° oriented fibers support transverse

stress,and the +_45° oriented fibers support torque stresses (shear).

A filament wound mandrel can be used to lay the 90 ° and +45 ° plies. By

using pegs placed in the proper positions, the fastener holes, actuator mounts,

and axle holes (see Fig. 3) are provided. Next, 0 ° U-D Pre-Preg tape is

applied to the outer surface and the entire beam is placed in an autoclave for

a short period of time. The resulting laminate will have 32 plies, but will only

be .34 inches thick. The weight of the beam will be very light (density= .0561

lb/in 3) in view of the strength and toughness characteristics provided. The

total cubic feet of the beams for the chassis is 5.64034; this gives a computed
weight of the chassis frame (composite beams only) of 546.78 lb (earth weight)

or 91.13 lb (moon weight).

The section fasteners are to be constructed out of a high strength

aluminum alloy, 2024AL. The aluminum density is .0975 lb/in 3 which is lighter

than most alloyed metals, and it possesses good fatigue and fracture

characteristics. The section fasteners provide an easy solution to the problem

of angling the fibers to conform to the chassis contours which tend to reduce

composite performance substantially. The fasteners will be joined to the beams

using aluminum or titanium rivets.

In the front section of the vehicle will be a compartment to house the

microcomputer, batteries, and fuel cell. The fiber composite compartment will

be produced in the same manner as the composite beams. The compartment

will be riveted to the chassis frame. This compartment will have a sealed lid,

so that it is easily accessible.

SOIL BUCKETS

The buckets used on the design of the LMTV have a dimensional

proportionality to the wheels which must be maintained. This is the major

constraint on the buckets. Therefore, they will be constructed with the

primary goal of saving weight. The relative proportions of the bucket are

shown in Figure 4.

It is desirable for the buckets to serve a dual purpose, if necessary. For

instance, the buckets could be used for the ends of a pressure vessel after the

moon base is completed. For this reason, it is difficult, at this time, to fully

specify the material and actual performance requirements of the buckets. It
seemslogical that the best approach would be sometype of compositematerial.

The buckets could then be made very lightweight yet the compositecould be

oriented in a mannerto serveasa pressurevessel.

A further consideration in the structural bowl design is the reinforcement

required at the dump mechanism connection and also at the stationary pivot

point. The amount of reinforcement will again depend on the inherent

strength of the bowl as it is designed for alternate uses. For the case of the

pressure vessel, they would likely be strong enough with no additional

reinforcement for use on the LMTV. On the other hand for a light duty

secondary usage, the material of the bowl may be just strong enough for

LMTV application.

Other factors governing the material selection must also be considered.

The two other primary considerations are temperature sensitivity and abrasion

resistance. Due to the tremendous temperature extremes encountered, the

material will have to function with very high reliability in an environment

ranging from -120°C to 120°C. It is desirable for the material properties to

remain relatively constant over that range.

Abrasion resistance will be another important consideration. Due to the

highly abrasive lunar soil, bowl wear must be expected even from simple

loading and dumping. It may be possible to construct the bowls with an inner

liner of material specifically designed to resist wear while the other layers

would be designed to give strength.

For our design purposes, the bowl size was maximized based on the power

requirements and motor performance. A wheel diameter of 4 feet corresponds

to a torque per wheel of 246 foot-pounds which is within our theoretical limit

for the motors. This wheel size defines a bowl size due to their constant
proportions. Thus, this definition yields a vehicle capacity and the capacity

weight is used to determine the required torque. After the final calculations,

the wheel sizeis set at 4 feet and the bowl diameter is setat 5.33feet.

This specifies the general size of the largest vehicle possible. The

dimensions of the bowl are shown in Figure 5. By using two of theses bowls,

the vehicles total carrying capacity is approximately 2,000 moon pounds of

lunar material.

WHEELS

The design constraints for the LMTV specify a four-wheeled vehicle.

Two wheels will be placed on each chassis half, near the line of action of the

center of mass of the bowl, as shown in Figure 1. This will serve to limit the

load at the steering joint. As discussed in the bowl section, the wheel

diameter can be determined by capacity and torque requirements for any given

bowl/wheel combination (Figure 6a,e).

The wheels will resemble those used on the Lunar Rover. The physical

dimensions are a four foot wheel diameter with an 18 inch wide tread. A

interwoven wire mesh design will be utilized. Eight hundred wires measuring

0.032 inches will be woven into a 0.25 inch mesh. Each wire will be crimped

at fixed intervals and then woven into a flat mesh. Tubular spacers will be

placed between the tread strip to prevent clamping of the wire mesh.

A cylinder will be formed with the mesh and will create the outer frame.

A stiff inner frame will provide support through absorption of impact loads and

this inner frame is essentially a stiff spring. The inner frame will limit

vertical and lateral direction of the outer frame. The tread strips will cover
approximately fifty percent of surface contact.

A stub axle will be utilized as the interface of the wheel and motor.

The diameter of the axis will be 2 inches and will designed for a 1,000 pound

force on each axle. The dimensions of the axle are given in Figure 3. A

fender will placed over each wheel to act as a blocker of wheel-induced

airborne soil.

The curvilinear synchronous motor will be incorporated into the hub of

the wheel and will be discussed in the Motors section. The wheel motion will

be a direct result of the power from the motor and this interaction of the

wheel and motor assemblies is essential for proper performance.

DUMP MECHANISM

The dumping mechanism for the LMTV will consist of a pair of linear

actuators operating under a tension load for the dump cycle. The exact

position of the bowl pivot point was determined based on ground clearance and

the requirement that the bowl rotate 110 °. The actuators will be placed on

either side of the bowl and lie along the inside of the chassis.

Because the fully loaded bowl will have a maximum capacity of

approximately 1000 moon lbs., each actuator must be capable of supplying half

of the force needed to dump. The maximum loading was determined to be at

the very beginning of the dump cycle. Our calculations show that a total

force of 800 lbs. or 400 lbs. per actuator will be required to initiate the

dumping action. The exact position of the actuators and their connection

points is shown in Figure 7. The line of action of the actuator remains

relatively constant throughout the range of motion in order to minimize any

10
mechanical loss due to misalignment or pulling at an angle. The actuators will

be computer controlled with sufficient feedback to prohibit binding due to

variations in actuator position or speed with respect to the other contributing

actuator. Our design utilizes the Duff-Norton Super-Pac Electromechanical

Actuators. These actuators are rated at 500 lbs. applied load and travel at

approximately 36 in/min using a 12 V DC motor drawing a maximum of 15

amps. These actuators were chosen for their simplicity, compactness, and the

fact that they are well sealed and maintenance free. These actuators contain

their own position transducers which will be used in the feedback control

system. It is estimated that using these actuators, a total dump cycle can be

executed in approximately 90 seconds, including a slight pause for direction

change.

MOTORS

Dr. Kent Davey (Georgia Tech Electrical Engineering Department) and

personnel at the Veterans Administration Medical Center are currently

designing a low speed fractional horsepower synchronous drive motor. This

motor will be applied as an alternative for the electric wheelchair motor. The

increased efficiency and reliability of the curvilinear synchronous motor are

advantages for implementation of this motor and replacement of existing

wheelchair motors.

The design of the curvilinear synchronous (CS) motor is applicable to a

motor for the LMTV. Through size, electrical and structural modifications, an

encased CS motor would be an excellent drive source for the LMTV. The

major attraction of the CS motor is efficiency and simplification by the direct

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drive mechanism. Through the projections, predications, and calculations of

Dr. Davey and this report, the CS motor can be utilized for the LMTV drive

mechanism.

The design for the LMTV will be a 3 foot radius, double-sided stator

motor. Current design of the CS motor requires a rotor as a rotating fixture

of the wheel and the stator as a non-rotating component of the wheel

assembly. The rotor section of the wheel is a set of magnets radially oriented

in the peripheral direction around the wheel. The magnets of the rotor are

currently designed with a ceramic material. The magnets are arranged in an

alternating north-south pattern. The stator consists of a three phase winding

embedded in a iron laminate. By alternating a three phase excitation of

current on the stator winding, control and torque generation can be achieved.

Although this motor is a direct drive DC motor, it can be considered as a

three-phase AC motor. The stator windings are arranged in a pattern of three

groups of winding slots that allow each group to be excited by single phase.

The three phase groups are offset by 120 degrees. The windings can be

considered as having a pole pitch equal to twice the tooth spacing. Every

other slot in a sector of the stator carries a current antiparallel to its

neighbor and therefore the wavelength is twice the slot spacing. The angle

between the windings is 7.20 degrees and this spacing is required for the

excitation of the windings (see Fig. 11, 12, 13, 14).

In the application of this smaller design to the larger structure for the

LMTV, the proportionality of the torque versus the radius of the rotor was

determined to be that the torque is equivalent to the square of the radius.

The LMTV design is capable of delivering a torque of 275 foot-pounds and

through calculations, the greatest amount of torque needed will be

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approximately 246 ft-lb.

The current requirementsare in direct proportional to the values of the

wheelchair motor; the CS motor for the LMTV will need approximately 55

amperes (Figure 9). The voltage will be 12 volts DC and this will be

provided by the fuel sourcesthat alsopower the other mechanismcontrols.

STEERING

The vehicle will be steered by an articulated mechanism utilizing

electromechanicallinear actuators (power screws). The steering of the vehicle

will also be aided by varying the wheel speed in sequencewith actuator

motion.

The steering mechanism is located between the two bodies. A pin

connects the point of the chassis to a plate thus providing a swivel for

turning. A bearing is located between the plate of each respective body

(Figure 10). this bearing provides free roll rotation of each body (i.e., when

one body is on an incline and the other is not). There are four actuators; two

located on each plate. The actuators are pinned to oppositesides of the plate

and connectedto the chassis. The coordinated retraction and extension of

theseactuatorsprovides the forces necessaryto turn the vehicle.

The actuators that we have chosen are Duff-Norton Mini-Pac

Electromechanical units. Theseactuatorsare rated for a maximum 100 pound

load with a speedof 145 inches/minute utilizing a special high speedmotor.

At maximum load, these12V DC motorswill require 21 amperes.

The action of the actuators and the individual wheel speedare controlled

by the on-board microcomputer. It has been determined through calculation

13
that the vehicle will have a turning circle radius of 16.5 feet (total turning

circle of 33 feet diameter).

This central section of the vehicle must also support the "tongue" weight

of each chassis half. The loading at the hinges has been calculated to be 148

pounds on each side at full load. For this reason, the pins have been

oversized at 2 inches diameter and 18 inches in length. It should be noted

that problems occur with the pin joints due to the extreme temperatures

incurred and the lack of liquid lubrication. This problem can be solved by

using a pressure and temperature impregnated teflon-like coating on the pins.

Coatings are now available which will easily withstand the temperature

extremes and provide dry permanent lubrication of the pins. The entire

steering mechanism will be enclosed with a flexible type structure in order to

keep out the abrasive lunar dust.

POWER

BATTERY SOURCE

The Viking Lander (Mars) contains two series-connected 35-watt

radioisotope thermoelectric generators (RTG) and four, 24-cell Nickel Cadmium

batteries. These batteries are long-usage batteries and can be regenerated

with the RTG apparatus after prolonged usage. This long-life characteristic

could be utilized in the power of the LMTV.

Research must be done for the adaptability of the battery system.

Currently, the voltage output is approximately 28 volts with a current of 8

amperes-hours. The weight of the batteries is 50.5 pounds per unit. The

necessity of the RTG and regenerative systems could be included but the

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weight of this system must be compared with the recharging advantages.

NiCd batteries are utilized in satellites and provide specific energy

densities of 10 Whr/kg at a 10% to 20% depths of discharge. In the

recharging process, there is a need to prevent overcharging due to the

sensitivity of the NiCd batteries.

FUEL CELLS

Regenerative monolithic fuel cell systems seem to attractive for space

application. The key qualities of this system is the simplicity of a solid state

system and the minimal heat rejection requirements. The fuel cell is highly

efficient in that there is no need for the heat rejection apparatus associated

with other systems.

The fuel cells utilize hydrogen and oxygen to provide power. Reactants

are stored as gas in tanks at elevated temperatures and pressures. The

gases,hydrogen and oxygen, are combined into water and the heat produced is

utilized to provide DC power. The products are stored after the temperature

has been reduced.

The system is capable of a regenerative process. The cell proceeds in a

reverse mode and the regenerative process is determined by the external

power source. The gases are stored into the product tanks.

The system can operate at temperature of 1,000°C and additional heat

injection may be required. The voltage and current output must be analyzed

before this system. The overall efficiency of this system is projected to be

66% in the overall electrical round trio from electrolysis back to regeneration.

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POWER REQUIREMENTS

The fuel cells and batteries are the energy sources to provide power for

the motors, actuators, and electronic and computer systems. All power sources

are ocated in the V-sections of the chassis and the connectors will run from

this area to the power demand.

The torque required for rolling only is estimated to be 50 ft-lb per

wheel. For a 20% grade, the per wheel torque demand is approximately 245 ftlb. The maximum theoretical torque output is calculated to be 295 ft-lb per

wheel. The horsepower per wheel is computed to be 0.664 hp for a flat

surface and 3.93 hp for a 20% grade. Calculations show that the dump

mechanism actuators must supply at least 0.0727 hp each.

CONTROLS

The on-board microcomputer controls all the functions of the vehicle.

This microcomputer is teleoperated from a base station on earth and/or the

lunar surface. This computer is located in the environmentally controlled

compartment which is located just in front of the bowl.

The computer must control the amperage from the batteries and fuel cell

supplied to the motors in each wheel, thus controlling the speed of the

vehicle. The computer must also control the activation and coordinated

control of the dump mechanism power screws for each bowl. The computer

also activates and coordinates the action of the steering actuators and the

wheel speed in order to turn the vehicle.

An extensive feedback control system will be required for the vehicle to

operate correctly. Each aspect of the LMTV's operation must be continuously

16
monitored for position and status. It may also be desired for the computer to

operate and receive input from some type of navigation/control system. It is

obvious that this vehicle will require a very powerful system. Due to the

complexity of the system and the rapidly changing technology, a system

specification is beyond the scope of this report.

HUMAN FACTORS - TELEOPERATION

An efficient interaction of humans and automation is necessary for

maximum productive output in space. The factors that need to be analyzed are

the role of humans in space, the man/machine interfaces, tools and procedures.

Start-of-the-art, totally autonomous robotic systems will not be available in

the near future. Remotely controlled systems utilizing human flexibility and

adaptability are in use and are being developed to increase the capability of

space operations.

The key element in the teleoperator process is the human operator. The

human interaction utilizes the perceptive, cognitive and decision-making

abilities and incorporates the natural human body and manual skills. The

performance of these factors will determine the overall efficiency of the

teleoperator process.

The efficiency issues are the time-constrained capabilities, perceptive and

cognitive limits, and the endurance and information assimilation rate and

capacity of the operator. The number of operators and the response time must

also be analyzed. The components of the teleoperator system are the

workstation, the interface unit, and the remote end effector and actuating

systems.

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CAMERAS

Definite perceptual limitations are inherent in a narrow field of view

system. Depending of the orientation of the Line of Sight (LOS) and the

video system relative to the longitudinal axis of the vehicle, a steep approach

may cause the horizon to be lost from view. If the vehicle is pitched up, the

runaway view may not be seen by the viewing system.

Variable Acuity Remote Viewing System (VARVS) was conceived as a

technique of integration of the human eye acuity function. The human eye

only requires 130,000 pixels for full support of vision. This factor is well

within the capabilities of conventional video systems.

The technique of the VARVS incorporates a non-linear optical system for

both the sensing and display equipment. A special lens is utilized and is

translated from a uniform pixel array on its image plane into the object field

as a variable angular array. This lens records the same angular detail the eye

would view and compresses the detail into a uniform matrix of equal-sized

picture elements on its image plane. Conventional transmission equipment can

be used to send the image information to a remote location.

The projected image must be viewed by the observer's eye aligned with

the projector optical axis to ensure high acuity and correct geometric

perspective. This optical system has very unique properties and a series of

psychophysiological studies on the interaction of human operators and remotely

controlled vehicles must be performed.

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COOLING/HEATING

The problem of controlling the temperature in the equipment housing is a

very difficult one. It is evident that during the lunar day a means of

dissipating heat must be incorporated into the design, and during the lunar

night, some equipment may need to be heated to function properly. A possible

solution to the cooling problem is that the equipment compartment be slightly

pressurized with any non-reactive gas. This would allow convection within the

compartment. A simple cooling system could then be installed in the

compartment utilizing a heat exchanger mounted on the underside of the

chassis in the shade. By using this approach, the equipment could be evenly

cooled with a very simple system. This system would also incorporate thermal

insulating and reflective blankets on the upper surfaces of the compartment.

During the lunar night, it may be necessary to allow the heat in the

equipment housing to remain, or the heat generated by the fuel cell and

computer system may still need to be dissipated. It is not possible at this

point to determine this aspect.

The second aspect of cooling is for the motors. These motors will

dissipate heat to the integral motor housing/heat sink and also to the entire

wheel. This method will effectively block the heat flow from the motors to

the chassis. All heat can be dissipated to the lunar soil and the wheels.

PRODUCTIVITY

The LMTV has been designed to operate at 10 mph. The design

objectives call for an average 1 mile round trip (loading and dumping cycle).

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The actual travel time per trip is approximately 6 minutes and a dump cycle

takes approximately 1.5 minutes. If two additional minutes are allowed for any

unforseen obstacles and turnaround or direction reversal procedures, a total

round trip, excluding loading, can be accomplished in approximately 9.5

minutes. The capacity of the LMTV is estimated at 100 ft 3 of material

weighing approximately 2000 lunar lbs. A loading rate has arbitrarily been

assumed at 5 ft a of material per minute. Using this value the loading time

would be 20 minutes. Therefore, the vehicle could carry out 2 complete cycles

per hour, thereby transporting 200 ft 3 of material per hour.

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CONCLUSIONS

The LMTV has been designed in an attempt to meet the needs of a lunar

construction process as set forth in the problem statement. The vehicle must

operate with high reliability under extreme conditions. The proposed vehicle

will meet the design objectives and constraints, although due to the size of

this project, future specialized development will be required. This project is

meant to serve more as a concept study than a finalized designed study due to

its wide scope and our relatively short allotted time period. The vehicle has

been designed based around an experimental DC motor. The largest vehicle

possible due to power considerations has been specified. The general layout

consists of three parts. There are two identical chassis halves, each of which

contains or supports a material carrying bucket, two individually powered

wheels, a fuel cell, a battery storage system, a variety of electromechanical

actuators, and a computer system. The third part of the system is the

articulated steering mechanism. This component allows the vehicle to be

steered by rotating the chassis halves relative to each other. It also allows

the chassis half to roll independently. The LMTV will be monitored by the

redundant computer systems and is capable of being remotely operated from

the lunar surface, earth and manually from the vehicle itself.

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RECOMMENDATIONS

The design of a vehicle such as the LMTV is very complex because each

system must be evaluated on its own and with regard to the vehicle as a

whole.

We feel that this project should be broken into smaller sections or more

time allotted for the development of the project. Some major areas that could

be further studied include:

1) REGENERATIVE BRAKING

A worthwhile method of incresing the LMTV power efficiency would be

through the recovery of the kinetic energy during deceleration or of the

potential energy created in the descent of an incline. The kinetic energy is

recovered through the charging of an on-board storage unit and the load

applied in the charging process will create a braking effect. The recovery of

the energy will increase the efficiency of the vehicle. This form of energy

recovery is referred to as regenerative braking and this process could be used

for the braking mechanism on the LMTV.

Regenerative braking involves a storage device to hold energy received

during braking until it is reused for propulsion. There must be a means of

transmitting the energy between the wheels and the storage device and a

means of controlling the degree of braking. Several methods of storage are

available including: mechanical, hydropnematic, thermal, and electrochemical.

The environmental constraints prohibit usage of the hydropnematic system and

size limitations restrict usage of the thermal and electrochemical systems. A

mechanical system could be utilized through a flywheel mechanism or through

22
capacitance storage. These options are discussed in the conclusions.

The mechanical system allows substantial power levels of charging and

discharging and the energy efficiencies can be high since no conversion of

energy states is necessary. The useful life is many million deep discharge

cycles. However, high quality and costly gear reduction systems may be

necessary for the drives. The environmental constraints need to be analyzed

before the storage system can be chosen.

Regenerative braking will greatly increase the efficiency of the total

vehicle and will recoup some of the expended energy. The LMTV will operate

in a straight line motion without frequent stops. The utilization of the

braking system should be limited to the complete stop of the LMTV at the end

of the haul process and to the deceleration of the vehicle at declines and at

the upper limits of the speed range. The assessment of energy impact and

recovery outweigh the cost and design factors of regenerative braking.

The regenerative braking could utilize the same electronic control

elements for motoring and braking functions. The method of storage could be

mechanical through a storage process and a battery system. By maintaining

computer monitored control with available human interaction, the speed of the

vehicle can be regulated from a small decrease in speed to a complete stop.

Through proper control and design, the regenerative braking could increase the

efficiency of the LMTV.

2) CHASSIS AND STEERING MECHANISM

It is recommended that an in depth study be made of the composite

chassis including a thorough stress analysis and more research be done on the

articulated steering joint. We also feel that the chassis could be made

23
considerably smaller with a next generation design by better utilization of

space available.

3) VEHICLE SIZE (SCALING)

An in depth study should be conducted to evaluate different sizes and

speeds of the LMTV. This project has attempted only to set an upper limit on

size based upon present motor technology.

4) SELF-RIGHTING

The problem of self-righting can be approached in many ways. It seems

that one of the simplest and most eloquent solutions is that of an oval shaped

roll over hoop. Using this method, if the vehicle were to overturm, it would

have no choice but to roll back onto its wheels. An entire study could be

conducted on self-righting possibilities.

24
ACKNOWLEDGEMENTS

1. Mr. Jim Brazell the hours of guidance and knowledge to get us on the

right path.

2. Dr. Kent Davey - for his input and literature on the curvilinear synchronous

motor.

3. Mr. Jim Criscuolo - the drawing and time spent discussing the model of the

CS motor.

4. Mr. Gary McMurray and Mr. Brice McLarin - for filling in the details and

support through out the quarter.

25
REFERENCES

American Nuclear Society. Viking Lander NiCd Battery Special Reconditioning

Sequences. 1982 Intersociety Energy Conversion Engineering Conference. Los

Angeles, California. Report 829125.

American Nuclear Society. Design Considerations For a 10-kW Integrated

Hydrogen-Oxygen Regenerative Fuel Cell System.1984 Intersociety Energy

Conversion Engineering Conference. San Francisco, California. Report 849218.

American Nuclear Society. Monolithic Fuel Ceils. 1986 Intersociety Energy

Conversion Engineering Conference. San Diego, California. Report 869375.

Ashton, Angustus, III, et al. Lunar Surface Transport Vehicle. Atlanta. Georgia

Institute of Technology, [1986].

Baumeister, T. M_rk'_ Han_lb00k for Mechanical Engineers. New York: McGraw

Hill Book Company, 1978.

Davey, Kent, et al. On the Design And Control Of Low

Horsepower Synchronous Drive Motors. Georgia Institute of

Veterans Administration Medical Center. [1987].

Speed Fractional

Technology and

Dilg, Jeff, et al. Lifting and Transport For Lunar Applications. Atlanta: Georgia

Institute of Technology, [1986].

26
ElectrochemicalSociety.Advances in Lead-Batteries. Pennington, N. J., 1984.

Hord, R. Michael. t_RC Handbook of Space Technology: Status and Proiections.

CRC Press, Inc. Boca Raton, Florida, 1985.

Martin, Louis. Storage Batteries _nd Rechargeable Cell Technology. Noyes Data

Corporation, Park Ridge, N. J., 1974.

Mendell, W. W. Lunar Bases and Space Activities of the 21st Century. Lunar

and Planetary Institute. [1985].

National Aeronautical and Space Administration (NASA). Lunar Rover Vehicle.

Report N72-12165, [1972].

NASA. Mechanical Accessories for Mobile Transports. Report DE85-014310,

[1985].

NASA. Regenerative Braking. Report UCRL-52306 Volumes 1 & 2.

NASA. Visual Systems for Remotely Controlled Vehicles. Report N85-14512,

[19851.

NASA. Wire Mesh Wheels. Report N70-29528, [1970].

Smith, Earl, et al. Lunar Material Transport Vehicle. Georgia Institute of

Technology. [1987].

27
_A_PLE _LC.UL-_T_OM_:

F_.,. F' = L "C:,,-= Ls'_) (..o¢') = Z.¢"

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MPD-6405

DUFF-NORTONM INI-PAC

ELECTROMECHANICAL

ACTUATORS WITH

BUILT-IN CLUTCH

The Duff-Norton Mini-Pac TM electromechanical actuator is

available in standard travels of 3, 6, 12 or 18 inches.

Its compact size, high speed and ease of installation make it

ideally adaptable toa wide variety of power applications. It can be

used indoors or outdoors*, for stationary or mobile

equipment--wherever there isa requirement for up to 18 inches of

linear motion of applied loads up to 500 pounds at speeds to 145

inches per minute. Speed varies with load, stroke and type of

motor specified.

The Mini-Pac TM actuator package, which weighs about eight

pounds (3" travel unit), consists of an enclosed electric motor, an

overtravel protector and load-limiting friction-disc clutch,a

patented automatic.set spring brake, D.C. unit& bat1 brake A.C.

unit, SuperoidTM gear set, and mechanical screw and nut with steel

translating tube and end fitting.

Motor may be specified for operation on standard (SPA-6405

MODEL) 115 VAC, single phase, 60 Hz, (for stationary

applications), or ona (MPD-6405 MODEL) 12 VDC battery system

(for mobile applications). Optional high-speed AC or DC motors

are available at extra cost (see descriptions on page 75).

All components are sealed ina corrosion-resistant, aluminum

alloy, die-cast housing with integral pivot mount. Optional 90o

clevis mount or mount with threaded insert are available at extra

cost.

Installation of the factory-assembled package Jsfast and

simple. It needs only to be supported witha single pin, attached to

its load with another pin, and wired to its power source and

controls.

1.1mit switches are recommended to protect motor and prevent

damage caused by overtravel.

Mlni-Pec TM actuators are available with built-in Ilmlt switches

(see page 76).

*(Consult Duff-Norton for outdoor applications)

TYPICAL APPLICATIONS

* Valve actuators• Truck cab tilters• Machinery leveling

and height adjustment• Web edge positioning• Feed

chute openers• Boat stern drive or outboard motor tilters

• Hospital bed adjustment• Fixture positioning= Flue

or damper actuation• Bus door operators• Spreader

control• Farm implement adjustments= Medical

examination table height adjustment= Dental chair

inclining mechanism

73
JFF-NORTON MINI-PAC'" ELECTROM ECHANICAL

;TUATORS

CHNICAL

©

Pivot Mount is integral part

aluminum alloy, die-cast

housing. Optional 90 ° clevis

mount or mount with threaded

insert are available at extra cost. 115 VAC or 12 VDC Motor

may be specified as prime

mover. High Speed AC or

DC motors are available at

extra cost. See data on

next page.

9

Housing and Motor

Adaptor are die-cast of

rugged, lightweight,

corrosion-resistant,

aluminum alloy.

Patented Spring Brake

D.C, Unit (Shown)

is hi-directional. No

adjustment required.

Minimal drift: less than

V4" with DC motor, under

=_" with AC motor, under

full load. AC units equipped

• with patented bell brake.

and'Plnion Bearlngs " " ":"_'" "-:

are of,trapped design to - .

'withstand compression...

"" and tension loads. -_ ;_ , .,Y ii_ : .

:. '-, Superoid"'GearSetfeatureshigh

•strength, high efficiency, and long

Y 'life. Gear and pinion have 20:1

Double Lead Screw and Nut feature

high efficiency and long wear. Screw

has rolled thread with high microinch finish; nut is of high quality

bronze alloy.

Screw and Nut Protector of 2"

diameter tubular aluminum shields

mechanical actuator from impacts

and corrosion.

jTrenslating_ Tube k; zinc.coated steel

_ _for added strength and weather ; _ "',

,.,,oc. Bronze Guide Bushing

I_ JB_J . Wiper Seal keeps dirt out reduces lateral movement

/ and lubricant in to assure of translating tube. Helps

/- longest operating life• maintain axial loading and reduces side thrust.

_ _ Friction.Disc Clutch is standard.

_ Freewheels at born ends of stroke, ORIGINAL PAGE IS

=_ Limit switches recommended to protect motor and prevent damage -- OF POOR QUALITY

i caused by overtravel.

, •_ " Clevll can be removed by unpinning

J - and unlmrewlng from t hrelded ecrew _ _ " "*_ SuperoM lee tmdemadc of Duff.Norton

( _ end. Any type of threaded connection' Co_,l lubeldlap/of Amofar

I f _ may be substituted, depending on

I _ /' application. Mini.Pac actuator may

I _ be specified from factory without U.S. PaL No¢ $_,499; 3,S87,71_ 3,/04,7B5

Other U.S. Ind ForMgn Patm applied for. clevis, if desired.

i
OPTIONAL

THREADED MOUNT

_z

! _)z .._aM- IDBUSNINa

NTERNA.., _. ._ _ . , _rv,L._,,, ",r. . ,

i. I _ ; O / I-, TRAVB. +4-1/2" , =1/11"

- THREAD _l.7rta- w • [ I---_---3-3/8"--.---._ t

- 2 "---.._ 1-3/$ (

33/54" I.D. BUSHING 3/4"

90" CLEVIS MOUNT _ s/_ "_ i I t I _ '--'t"

"T'- ....... T-_;_"7" I/ I I ..... "f _ _-:){I'X_4"WIOE

] MOTOR ADAPTOR J _ _," ) J

I & BRAKE HOUSING 121t32" R. _ L _ _ I ..... t

ACTUATOR / I Y" I

• / I I I][ I IHOU$ING -- (" ' ' MOTOR ADAPTOR OIRT ;EAL\

| / _i _ _, I I x,BRAKe HOUSING t \

/ I F _ _ _ _ I TRAVELING NUT &

I__ _ 7 11/16 I TELESCOPING TUBE 11-1/4" DIA.) I I

f2".20.3A

8-5/ S° I I ]PERMANENT // I _ THREAD

115 VOLT MAGNET ;"_o° ,

........... I | j DO MOTOR OPTIONAL END

f _., LESS CLEVIS i

sP.,O M.o.,os

"H 115 V. 60 Hz AC MOTOR

_ed

bd

s.)

0

0

0

0

0

:died ]

)acl i

i=sJ I

2

Nots: Dimensions are

S_.,d

(Inlmln)

Optlonal

Standard High Speed

Moto_r Motor

(SPA,.640$) (HSPA-6405)

42 80

41 75

39 73

37 70

Amps

Smeda_ OptiOnal

Meteor High Spell

Motor

2.5 450

2,55 4.80

2.6. 4.65

2.88 4.70

• , 2.7 4.80

12 V. DC MOTOR

Speed

(INmin)

Standard Optional

Motor Higtl Speed

Motor

(MPD-6405) (HM P0-6405)

I

Amps

t Slel_lord _ Optional ! HIQI1 Speed

Motor I " Motor

m I

' 13

f CAPAC|TOR

-:¢0\ I [

0_< N

:,.J-i

.o

CUSTOMER REVERSING SWITCH .,_

Minimum voltage 103.S

CW - R.tr.ct; CCW - Ext.nd _¢dt_ nld_

me Actuator

r CUsToMER _" " _"

1 DOUBLE POLE

I | DOUBLE THROW SWrrCN -._

1_<o I I I/ Cw, _ _1 I>:=_, I _ .... ; I _ I

I_,_/ : _.._*; _ _1

L _- JUMpLrR WIRES

68 14,5

60 132

52 120

42

32

ITY CYCLE CHART

eOuty Cycle (Ihchee Per HOur|

AC Motto'

Standard Hlgb Sgaed

28-33 mid 64-77 mfd

P_lpe¢itor Capacitor

5_ .¢90

540

520 470

500 4a5

44O 45o

I DO Moto_

21

28

36

Standard

DC Moloe

ZS_O' r350

1750 I0_0

toe0 7O0

360

High Speed

DC Motor

|l Inches trlivol (up end down| per hour with squaldy timed Intli_llls

vmm cyclll.

"22 stops n,mning; 30 =rnps atell

CrW =,Retract; COW - Extend

ORIGINAL PAGE IS

OF POOi_ QUALITY

subject to change without notice,

115 VAC Motor is enclosed, permanent

split capacitor induction type. Load/

no-load speeds are approximately

equal. Equipped with thermal overload

which opens and resets automatically.

Standard motor requires 28-33 mid

capacitor (supplied by customer, or by

Duff-Norton at additional cost) for loads

up to 500 pounds. A capacitor box is

avaitabte on AC ruDders onty, to provide

an enclosure for electrical connections

and to give a convenient conduit

installation.

12 VOC Motor is totally enclosed,

weather-resistant, permanent magnet

type. Magnets act as secondary brake

for added safety. Smaller, more efficient,

cooler running, with higher duty cycle

than series-wound designs. Lower

current draw for longer battery life,

Equipped with thermal overload trtat

opens and resets automaticafly. Rotation

reversible by reversing two color-coded

leads; torque equal in bo(h directions.

A high-speed DC motor is available at

extra cost.

The littoral cmm'_l mtly meetl In 10 ee_ tl sill DC mol_,

_l_l i_hlgt_ Iq:e_l mm_, 10 m_,/_ AC molem _ 8tanm_l "n_l

OUly _ i cm _" smaMnt teml_etu_.

NOTE: The new SPA Sodas Mlni-Pac'"sctustora (AC models

without limit switches) supersede the previous MPA Serial

equivalent models. The SPA sctustors incorporate major internal

advancements, principally in the brske design, while the external

dimensions remain unchanged. SPA Series models wlll serve ss

direct field replacements for MPA SenBs actuators.

NOTE: Some actuator external surface temperatures may reach

230°F during use at or near maximum duty cycle. All ratings are

nominal and are based on actuator being broken.in for approximately 2500 inches of travel.

NOTE: ThB data listacl is from our test results. Your data may differ.
3FF-NORTON SUPER-PAC"

.ECTROMECHANICAL ACTUATORS

_)uff-Norton Super-Pac TM electromechanical actuator is

able in standard travels of 3, 6, 12, 18 and 24 inches.

compact size, light weight, high speed and ease of

Lllation make it especially adaptable to a variety of

ications requiring the movement or positioning of heavier

s. Models are available for stationary or mobile

;)ment--wherever there is a requirement for linear motion of

led loads up to 1500 pounds, at speeds to 50 inches per

Jte.

)eed wil vary with the load and the type of motor specified.

)r may be specified for operation on standard 115 VAC, single

_e,60 Hz (for stationary applications), or on a 12 VDC system

nobile applications).

_estandard AC unit has built-in adjustable limit switches to

rolthe stroke. The limit switches can be set to stop the motion

e lifting screw at any point required by the application. The

:age weighs only 25 pounds, including motor. (For 3" travel

le standard DC unit has a built-in friction-disc clutch.

le built-in friction-disc clutch can be set externally to slip at

"lesired capacity, thereby protecting the actuator and your

pment from excessive shock loads. However, limit switches

ecommended to protect the motor.

3th AC and DC Super-Pac actuators have an automatic-set

lg brake, Evoloid* gear set and mechanical screw and nut

steel translating tube. All components are sealed in a

)sion-resistant cast aluminum alloy housing. The unit comes

)u complete--mady to be insta led. Optional trunnion mount

ailable at extra cost. An optional weather-resistant treatment

ailable tor outdoor applications.

) install, just support with one pin, attach the load with

her pin and wire the package to its power source and controls.

remote screw position indicating system is available

onal, extra cost) in case the actuator is operated from a

_te location, such as from another building or from a central

:rol console.

TYPICAL APPLICATIONS

, Valve actuators • Farm implement adjustments

, Heating/air conditioning flue and damper actuators

, Fixture positioning * Door openers for laundry extractors,

urnaces, incinerators, freezers • Conveyor height adjustnent • Solar collector positioning • Printing press roll

_djustment. Feed chute openers • Idler wheel positionng for belt-tension

i.,

,

ubhshed trademark of Quaker City Gear Company Incorporated

SPA.6415 Q
-INICAL DATA

Umit switches are protected by sealed weatherresistant cover. Optional position

transducer is mounted

within limit switch _ x

enclosure.

Easily adjustable limit t

switches control the _ I II

stroke of the actuator

_tage gear set corn- I I

;the patented Evo- _._ A II

lear set with spur _ _ _ II

ng for smooth, quiet_ ___J===L__,

ztlon. •

Pivot mount can be ordered in

desired position. Any type Of

threaded end may be sul_tituted

on special order, depending on

application.

for optional trunnion

ding.

_rand long weer - :.,_'. _-_[

Vent prevents pressure

build-up in the actuator. __

Aluminum tubing protects

screw and nut.

TransJatlng tube is zinc

coated for weather

resistance.

Bronze guide bushing J

reduces lateral movement " /

of translating tube. /

Wiper-scrapm seal keeps j

dirt out and lubrlcltlon in.

_is end is standard. A threaded

::1Is available and any type of

_:lecl connection may be subIuted on special order, dependIon application. I

f

Capacitor box provides a

weatherproof enclosure

for the motor capacitor.

Threaded access to motor

leads provides for conduit

connection.

Motor leads are internally

routed and connected to

capacitor and limit

switches.

Housing and cover are

sand cast of rugged, lightweight, corrosion-resistant aluminum alloy.

Spdng brake is a bidirectional no.back type,

automatically actuated by

•pinion tondo¢_ Released ....

_'when motor turns. Design,

features harde_edstee_ ._.

•spdng, No adlustment

required. Maximum drift:

less than _1_"with DC;

motor, and _t_!°with AC

motor under full load.

115 VAC motor Is pdme

mover.

ORIGINAL PAGE IS

OF POOR QUALITY

Screw ddver slot In motor

at_=ft for power-off,

manual operation.

The 12 VDC _.-tuator as shown

on page 83 is pr_ with a

fdctlon-dlec clutch in plsce of

adjustable llmlt switches. It freeWlliNHI at Ix_h ecKle of the stroke

to protect the actuator and edulpment from severe shock lO8_S.

81
t

=1- t ,..,o

1 _ / I _Jl,0 -- / ==-

, , Tirmtnall for .is o_ _ _"

I I 1 _._// I \ ./ =I|

_.r, I

+_ 2._,/ -J J"

i_L. i I ..-x" 1

_ -r-

;_ 10_-'- -_-_-d d 1"--_

"-" :_ I , I I i I / |i

4-, r ! j

' ' " "_ ,_. _,9' ;.._:_ ._._ f

----J- 3/4 Dictator Holil ,

Trlvol Clelll End _ _ '

a 1.00 Wide

SPD.e41S(OQ

12 VDC Motor is totally enclosed, weatherresistant, permanent magnet type. Magnets act

_s secondary brake for added safety. Smaller,

more efficient, cooler.running, with higher duty

cycle than series-wound designs. Lower

current draw for longer battery life• Rotation

reversible by reversing two color-coded leads;

torque equal in both directions.

CUSTOMER'

i OOUeLE POLE

>,il 0 , , .

I_. _1 !Dtc_ ! _1

I "_=-A__._J---_t:: =l I_ J/__. - I ,÷;

WARNINQ: I

1. Slierc all,field will cain latherer clutch to IIIp I

and allow thl laid Io till lower. I

2. Maximum IIIowibll bending moment On S/8" I

threaded Ihank under normal O¢Nlrailng ¢ondl- I

Ileal il 300 inch, pounds. I

3. Position hooded vent to prevent molature and dirt I

from Intorthg actuator (see Instruction and I

lltntlnin¢l lhC@l). I

4. Soma actuator external lUrllCn temperatures i

lay filch 130"l during lie it or near maximum '

/llowaDll duty cycle.

$. Duty cycle and ¢onlinuoui duty ratings of the

actuator should not be CXClNld@d. TO do SO COuld

cause damage tO the motor thus voiding any

wan'anty on the motor, See Initrictlol_ and _1

malntlnlnco shell for thlli rlllngl. I

@. FOr luit ripllcilanl ill only LIII|ItuIi Part NO. I

SI1025 ($ at, 32 volt, 25 Imp) rnedlum a¢fln e

tisel.

I, DO not p|lCl foreign obillil in till lull hold@f or

use tiles not meomm_ ay Duff.Norta_n Co.

WITH 12 V.

Applied

Load

{Ibl.) (an/mini

$oo 36

tOO0 31

_500 20

DC MOTOR

Aml_

_5

21

2?

_Duty (iNhr_

15_O

2OO

tloill In¢llto ot travel lip and down) per hour wtth Kluilly timed Intnillll i_ltween

cy¢lN.

ORIGINAL PAGE IS

OF POOR QUALITY

1

I

I

!: Both duty charts are based on 75"F ambient tempera.

All ratings are nominal and ire based on actuator being

_n.ln for approximately 2500 inches of travel,

The data listed Is from our test results. Your data may differ.

Note: Dimensions ire subject to change without notice.

63
PROGRESS REPORT

WEEK 1 ............. LUNAR DUMP TRUCK

ME 4182

Charlie Fisher

Cass Whitehead

Allen Wilkens

This week we had our first group meeting and received the initial

information about our project. We will be developing one possible design for

a lunar dump truck. This first week was devoted purely to organization and

initial background research. The following items have been addressed.

1. We have reviewed the report submitted by last quarters group and

discussed some rough ideas.

2. We have set up two group meetings per week, one on Mondays at 3:00

and one on Thursdays at 3:00.

3. We have made an initial attempt to locate available information which

may be of use on this project.

4. Plans for next week include assigning specific areas of research for team

members and defining the constraints exactly for the entire project.
Progress Report

Week 2

Charlie Fisher

Doug Lyons

Harry Whitehead

Allen Wilkins

January20,1987

We have identified a large number of reports of significance to our project.

A considerable amount of time will be devoted to the study of these reports and

noting problems incurred along with technology developed.

We have divided our project and research into four basic areas: Power,

Wheels, Controls, and Chassis. These areas were then broken down into more

specific areas as shown in our organization wheel. This wheel will serve to

organize our research and pinpoint areas needing further investigation

Our plans for the upcoming week include a series of brainstorming sessions

in order to solidify the basic concept for the project design. At this time the group

will assign specific areas of concentration for each team member..
Lunar

Dump

Truck

\
Progress Report

Week 3 ......... LunarMaterial Transport Vehicle

2harlie Fisher

Ooug Lyons

Harry Whitehead

Allen Wilkins

Ianuary 27, 1987

This week the group concentrated mainly on formulating a concise problem statement

:onsisting of a set of performance objectives and a set of system constraints. A copy of this

problem statement is attached. In addition, the following items were acted upon as indicated.

• The reports identified last week are not available in the GT library and

must be ordered from NASA.

• The management of the four basic areas to be developed has been

divided as follows.

Wheels & Chassis -- Cass and Allen

Power -- Charlie

Controls -- Doug

• Several brainstorming sessions were held this week. This has resulted

in a solidification of the general layout for the vehicle as shown on the

attached graphic.

• Measurements were made to the scale model from last quarter in order

to specify the dimensional relationship between the wheels and

buckets.

• During the brainstorming sessions some rough calculations were done to evaluate

the power needed to drive the vehicle. We have determined that somewhere

between 1000 and 2000-ft.-lbs. of torque will be required per wheel in order to

climb a 20 degree incline. We have made several attempts to contact Dr. Davey in

order to discuss future power predictions for his motors.

• Charlie is currently in the process of gathering power information

from truck manufacturers to see if any power to capacity relationship

can be made.

° We have decided that it may be beneficial if all or several members of

our group could visit the Huntsville center in order to study the lunar

rover which is on display there.
LUNAR BULK MATERIAL TRANSPORTER

PROBLEM STATEMENT

With the possibility of colonizing the lunar surface, a definite need would

exist for the transport of lunar soil and other bulk materials. A suitable vehicle

must be designed, within the following objectives and constraints, for this purpose.

OBJECTIVES

PERFORMANCE

SLOPE

The loaded vehicle should be able to perform on a 20% grade.

SPEED

The loaded vehicle should be able to operate in a range of 5 to

15 mph.

TRACTION

The vehicle should be designed in order to provide sufficient traction

on the lunar surface.

SELF-RIDING

The vehicle must be able to maneuver itself out of all possible situations.

SPECIFICATIONS

GENERAL

The vehicle must be as mechanically simple as possible in order to ensure

maximum reliability.

LOW HORSEPOWER

The loaded vehicle must be able to operate on 5 - 15 hp.

LOW CENTER OF GRAVITY

Due to the 1/6 gravity force on the lunar surface, the center of

gravity must be as low as possible to prevent easy overturning.

GROSS WEIGHT

The gross weight must be kept to a minimum due to the extreme

high shipping cost.

CONTROL

The operation of the vehicle should be controllable from the

following: a local controller, an earth based controller, and from

the vehicle itself.

SIZE

The following factors will be considered in the determination of the

vehicle size: turning radius, wheel size, bucket capacity, and overall

dimensions.
BRAKING

It is desirable to engage a regenerative braking system.

CONSTRAINTS

GENERAL

BODY

The vehicle must operate on four wheels with two bodies and two buckets.

BODY PROPORTIONS

The proportion and shape of the wheels to the buckets must be

constant, as it is desirable to have interchangeable parts with other

proposed lunar devices.

OPERATIONAL

The operating range of the vehicle is limited to line-of-sight due to the

transmission characteristics of radio equipment operating in a vacuum.

The vehicle must be able to withstand extreme temperature differences

(- 120°F to + 120°F).

The vehicle must be able to operate in a vacuum.

The vehicle must reliably operate in the highly abrasive lunar environment.
LUNAR MATERIAL

TRANSPORT VEHICLE

BULK

MATERIAL

BUCKET

PlVIDUALLY

WERED

IEELS

FUEL CELL

&

CPU

IOINTED

FOR ARTICULATED

STEERING

BULK

MATERIAL

• BUCKET

INITIAL DESIGN CONCEPT
Progress Report

Week 4 ......... Lunar Material Transport Vehicle

Charlie Fisher

Doug Lyons

Harry Whitehead

Allen Wilkins

February 3, 1987

This week the calculations were begun in order to determine the realistic size envelope

for the LMTV. Simplified calculations were performed and the attached graphs show their results.

The group has set up a meeting with Dr. Davey from the EE department for Friday February 5 at

4:00 p.m. At this time we will discuss the realistic possibilities for his motors.

This week we have also gathered some information on the lunar soil characteristics and

mechanics. This information was required on order to determine the load capacities etc.

As a result of our meeting last week we now have a more realistic idea of the general

size that the vehicle should be. We have therefore redefined our constraints somewhat in order to

reflect these changes.

Following our meeting on Friday we hope to be able to define the maximum size

vehicle possible. From that point we can scale down in order to achieve any desired possible size.

This will enable us to optimize the vehicle size for a given application. For example, the capacity

will depend on the length of the trip that the vehicle will be needed for. We hope that for next

weeks presentation we will have a well def'med vehicle.
O

('JA) _I3J_31gVIG "IA_09
Bowl Diameter VS. Wheel Diameter for LMTV

6

0

0 2 4 6 8 10

Bowl Diameter (ft.)
Bowl Diameter VS. Total Volume for LMTV

500

40O

_, 300

=__..

0

20O I100

0

0 2 4 6 8

Bowl Diameter (ft.)
[- oO

('Slt'I NIOOIAI) A,LIDVJVD
Bowl Diameter VS. Torque / Wheel for LMTV

tO

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2O

10

| • I

0 1 2 3 4

Bowl Diameter (ft.)
Progress Report

Week 5 ......... Lunar Material Transport Vehicle

Charlie Fisher

Doug Lyons

Harry Whitehead

Allen Wilkins

February 10, 1987

This week our group met with Dr. Davey to discuss the curvilinear

synchronous motors. We discussed scaling and size parameters for the motors.

This has enabled us to generate graphs showing motor performance versus motor

size. By comparing this information with the power required information we have

narrowed our vehicle size to a specific range as shown on our graphs.

Also this past week we have begun gathering information on fuel cells.

We hope to define the power requirements during the upcoming week. After this

has been done we should be able to specify a particular fuel cell setup.

We have begun a material study for the vehicle chassis. We have contacted

a graduate student who is involved in material science specializing in composites.

In the coming week we hope to narrow the possibilities to only a few very good

alternatives.
_J

('sqi-'lj) _I_1_)_I01
Progress Report

Week 6 ......... Lunar Material Transport Vehicle

Charlie Fisher

Doug Lyons

Harry Whitehead

Allen Wilkins

February 17, 1988

This week we continued to look for information concerning fuel cells.

We looked at several technical papers in the Intersociety Energy Conversion

Engineering Conference (1984,1986) publications. Several systems were analyzed

and the H/O regenerative fuel cell system seems to be the most suitable for our

application. However, this system presents some difficulties (i.e. temperature and

efficiency relationships) which will require further study.

A study is being performed conceming bowl rotation geometries in order

to determine ground clearance at various pivot points. This study will aid in the

determination of dump mechanism requirements, center of gravity calculations,

limits for ground clearance, and rate of material dump.

We are also continuing our search and analysis of composite structure

design. The arrival of NASA reports concerning the lunar rover and wheel design

is anticipated, so that more information can be gathered in these areas. In the

upcoming week, we expect to identify and analyze types and geometries of various

dump mechanisms.
Progress Report

Week 7 ......... Lunar Material Transport Vehicle

Charlie Fisher

Doug Lyons

Harry Whitehead

Allen Wilkins

February 24, 1988

This week our group made a check list for all areas of our project. Thus

we recognized areas that require further concentration.

The pivot point of our bowl has been determined as shown in the graphic.

This pivot point allows for adequate ground clearance when the bowl is rotated a

full 110 degrees. The dump mechanism for this bowl will be a slider crank

mechanism which will be mounted to the frame on each side of the bowl. This

mechanism will be computer controlled to insure exact simultaneous motion on

each side of the bowl.

The chassis for our vehicle will be a composite with a box cross section.

The size of this cross section will be determined as the composite characteristics are

determined.

The power for the vehicle will consist of hydrogen/oxygen fuel cells

which will be mounted in the controller section. The environment of this controller

section will be maintained at a workable temperature. Lead acid batteries will be

mounted in the frame box section near each motor. The fuel ceils will constantly

recharge these batteries.

In the upcoming week, our group plans to observe an articulated steering

machine at the Yancey Bros.-Caterpillar location in west Atlanta. We also plan to

calculate the slider crank forces and their exact positioning.
iiiiiiiiiiii!i!iiii_iiiiiiiiiii!iiiiiiiiiiiiiiiiiiiiii_!i!iiiiii_iii

i_iiiiiiiiiiii_ii_iiii_iii_ii_ii_iiT_
Record of Invention No.

UTC No. (if applicable)

GEORGIA INSTITUTE OF TECHNOLOGY

APPROVAL SHEET (Attach to DISCLOSURE OF INVENTION)

The following questions should be answered by the laboratory or school director,

asapplicable. The questions are designed to verify the ownership of the invention. This approval should be included when the Invention Disclosure form is

submitted to the Office of Technology Transfer.

I. Title of Invention:

Lunar Material Transport Vehicle

2. List of Inventor(s):

Harry C. Whitehead, Jr. Charles D. Fisher

W. Allen Wilkins, Jr Douglas Lyons

Ownership:

In my opinion this invention:

__z._A. Is owned by the Institute in accordance with the Patent Policy.

B. Was developed by the inventor(s) without use of Institute time,

facilities or mterlals, and is not related to the inventor's area

' of technical responsibility to the Institute and hence belongs

to the inventor(s).

4. Research project advisor approval for student submissions (if applicable):

Advisor Date

Reviewed for Institute ownership by laboratory or school director.

Name Date

Title/Unit

9/87
Record of Invention No.

UTC No. (if applicable)

GEORGIA INSTIIXrrE OF TECHNOLOGY

DISCLOStrRE OF INVEI_ION

;ubmit this disclosure to the Office of Technology Transfer (OTT) or contact

:hat office for assistance. Disclosure must contain the following items: (I)

:itle of invention, (2) a complete stat_nt of invention and suggested scope,

3) results demonstrating that the concept is valid, (4) variations and alterrate forms of the invention, (5) a statement of the novel features of the inven-

:ion and how these features distinguish your invention from the state of the art

ts known to you, (6) applications of the technology, and (7) supporting informa-

:ion.

Title

Technical Title: Lunar Material Transport Vehicle

La_nnan's Title (34 characters maximum, including spaces): A moon surface

mover of'ibu]k material0

Inventor(s): (Correspondence, patent questions, etc. will be directed to the

first named inventor)

A. Signature'S. __ Revenue Share% Date3/9/_'

Printed Name Harry Cans Whitehead, Jr. Citizenship U.S.A.

First Middle Last

Home Address 914 Collier Road, Apt S1

City Atlanta Count Z Fu%ton

Campus Unlt/Mall Address

StateGeorgiazip Code 30318

Campus Phone 355-8895
Record of Invention No.

UTC No. (if applicable)

DISCLOSURE OF INVENTION

2. Statement of Invention:

Give a complete description of the invention. If necessary, use additional

pages, drawings, diagrams, etc. Description may be by reference to a separate document (copy of a report, a preprint, grant application, or the like)

attached hereto. If so, identify the document positively. The description

should include the best mode that you presently contemplate for making (the

apparatus or material invented) or for carrying out the process invented.

Inventor(s) _ /]//__-

//. _/J:$,a _.

,_o.,.. /',/_ //F_/

Date_I_I_

Date -_/_/_9

O

Date

_The witness should be technically competent and understand the invention.

9/87 Page 2 of 7
Record of Invention No.

UTC No. (if applicable)

DISCLOSURE OF INVENTION

Results Demonstrating the Concept is Valid:

Cite specific results to date. Indicate whether you have completed preliminary research, laboratory model, or prototype testing.

Variations and Alternative Forms of the Invention:

State all of the alternate forms envisioned to be within the full scope of

the invention. List all potential applications and forms of the invention,

whether currently proven or not. (For example, chemical inventions should

consider all derivatives, analogues,

section. Indicate what testing, if

nate forms.

etc.) Be speculative in answering this

any, you have conducted on these alterCO'_SF,-_,,'_ ,I,,.s _4u Ol,,,_r.._.l-,'_.,_c.

Inventor(s)

Witness*

¢

(printed name)

9/87

(printed name)

Date 3/ 9 16_

Date -_../_/_

o,,.zloq( 

VcDate

Date

Page 3 of 7
Record of Invention No.

UTC No. (if applicable)

DISCLOSURE OF INVENTION

Novel Features :

a. Specify the novel features of your invention. How does the invention

b, What deficiencies or limitations in the present technology does your

overcome?

Co

I

Have you or an associate searched the scientific literature with

respect to this invention? Yes _ No . Have you done a patent

search7 Yes No _ . If yes in either case, or both, indicate

what pertinent information you found and enclose copies if available.

Also indicate any other art you are aware of (whatever the source of

your information) that is pertinent to your invention. Enclose copies

of descriptions if available. (Note: An inventor is under duty by law

to disclose to the U.S. Patent and Trademark Office any prior art known

to him or her.)

inventor(s) _ /__....2 _.

.b.

Witness

(printed name)

(printed name)

Date

Date

Date

Date

Date

)/87 Page 4 of 7
Record of Invention No.

UTC No. (if applicable)

DISCLOSURE OF INVENTION

Application of the Technology:

List all products you envision resulting from this invention. For

each, indicate whether the product could be developed in the near term

(less than 2 years) or would require long-term development (more than 2

years).

Inventor(s) __ _#_-__"/I _-'t, .-

/ _

Witness.

(printed name)

(printed name)

Date

Date

9/87 Page 5 of 7
Record of Invention No.

UTC No. (if applicable)

DISCLOSURE OF INVENTION

SUPPORTING INFORMATION

Are there publications such as theses, reports, preprints, reprints, etc.

pertaining to the invention? Please list with publication dates. Include

manuscripts (submitted or not), news releases, feature articles and items

from internal publications. Supply copies if possible.

566

On what dat_ was the invention first conceived? //&/[_Jls this date documented?/_Where? ._.------- Are laboratory records

and data available? Give reference numbers and physical location, but do

not enclose.

Give date, place, and circumstances of any disclosure.

cific individuals, give names and dates.

If disclosed to speWas the work that led to the invention sp/onsored by an entity external to

Georgia Institute of Technology? Yes VNo

a) If yes, has sponsor been notified? Yes J No

b) Sponsor Names: __

GIT Project Nos.

What firms do you think may be interested, in the invention and why.

specific persons within the companies if possible.

Name

Page 6 of 7
Record of Invention No.

UTC No. (if applicable)

DISCLOSURE OF INVENTION

SUPPORTING INFORMATION

Setting aside your personal interest, what do you see as the greatest

obstacles to the adoption of your Inventlon7

Alternate Technology and Competition:

a. Describe alternate technologies of which you are aware that accomplish

the purpose of the invention.

ga e

b. List the companies and their products currently on the market which make

use of these alternate technologies.

c. List any research groups currently engaged in research and development in

this area.

Future Research Plans:

a. What additional research is needed to complete development and testing of

the invention? What time frame and estimated budget is needed for the

completion of each step7

b. Is this additional research presently being undertaken? Yes No_

c. If yes, under whose sponsorship?

d. If no, should corporate sponsorship be pursued? YesS____ No

Suggested corporatlon(s)__

Attach, sign and date additional sheets if necessary. Enclose sketches,

drawings, photographs and other materials that help illustrate the description. (Rough'artwork, flow sheets, Polaroid photographs and penciled graphs

are satisfactory as long as they tell a clear and understandable story.)

)/87 Page 7 of 7
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