Table of Contents
THE SYSTEM DYNAMICS APPROACH TO
DEVELOPING AVCS MAGLEV VEHICLE
DEVELOPMENT MODEL
SANG HYUP LEE
Korea Transport Institute, 2311, Daehwa-Dong, Ilsan-Gu, Koyang-Shi,
Kyunggi-Do 411-701, KOREA
Tel: 82-31-910-3110, Fax: 82-31-910-3228, Email: infohi2@ koti.re.kr
AVCS maglev is the synergistic combination of Advanced Vehicle Control Systems (AVCS) and
the high-speed magnetic levitation (Maglev) technology. AVCS maglev will provide a safe, high-
speed, high-capacity, energy-efficient, environment-friendly intercity and intracity transportation
system. The vehicles using the "magway" (maglev guideway), like present day automobiles,
would be privately owned and could operate on ordinary highways and streets as well as the
AVCS magways. In this paper, the AVCS Maglev Vehicle Development Model (VDM) is
developed to outline the important factors in reducing the weight and the price of the vehicle.
Reducing the weight of the vehicle will help increase the operating efficiency and reducing the
price will help increase the accessibility to this highly beneficial transportation system. The
AVCS Maglev Vehicle Development Model is described in two complementary forms of the
system dynamics modeling, causal diagrams and DY NA MO equations.
Keywords: AVCS maglev, Vehicle Development Model, causal diagram, DY NAMO
Features of AVCS Maglev Transportation System
Overview
AVCS maglev (Lee, 2002) is the synergistic combination of Advanced Vehicle Control
Systems (AVCS) and the high-speed magnetic levitation (Maglev) technology. AVCS
maglev vehicles would be designed with dual capabilities permitting them to run on
maglev guideways (magways) as well as conventional roadways.
The structural and geometric design requirements for AVCS maglev guideways
would be much less demanding than for maglev trains. These maglev vehicles, operating
on guideways constructed in freeway medians, would have to negotiate almost the same
tums and grades as lower-speed freeway traffic. Continually accelerating and
decelerating to negotiate turns would be compromising to speed, capacity and comfort.
Since centrifugal force increases as the square of velocity, the guideway must allow the
vehicle to bank with substantial angles.
AVCS maglev would be an electrodynamic suspension system. The repulsive force
between the vehicle-bome superconducting magnets and the guideway electromagnets
would keep the levitation height at a level of over 4 inches. The linear synchronous
motor would propel the vehicle at speeds of up to 300 mph (see Figure 1).
Features
Features of AVCS maglev would include: (1) advanced technology, (2) ultra-high speed,
(3) unmatched capacity, (4) improved safety, (5) innovative form, (6) energy benefit, (7)
environmental protection, and (8) economic development. Each will be discussed briefly.
Superconductivity is a phenomenon in which electric resistance of a specific material
approaches zero at low temperatures. A superconducting magnet is an electric magnet
made of a superconductive material. Without electric resistance, once the electric
current is circulated, it flows continuously. Very strong magnetic forces can be obtained
from relatively small magnets.
The three primary functions basic to an AVCS maglev transportation system are
levitation (or suspension), guidance and propulsion. It is believed that magnetic forces
would be used to perform all three functions. The vehicle is levitated by the repulsive
force between magnets. When the high-speed vehicle with superconducting magnets on-
board approaches and passes over the ground coils, the ground coils tum into
electromagnets by the induced current.
The vehicle with superconducting magnets on-board is propelled by the attractive and
repulsive force between the magnets. The ground coils for propulsion and guidance on
both sides of the guideway are controlled so as to be the S pole or N pole electromagnets
altematively by the electric current supplied from the substations. The interaction
between the superconducting magnets in the vehicle and the electromagnets on the
ground is the driving force of the ultra-high speed.
The guidance system provides the sideward forces that are required to make the
vehicle follow the curves and straightaways of the guideway. The necessary forces are
supplied in an exactly analogous fashion to the suspension forces, either attractive or
repulsive. The same magnets on-board the vehicle which supply levitation forces can be
used concurrently for guidance, or separate guidance magnets can be used. With an
automatic longitudinal control system, vehicles can be operated with very small
headways and the travel speeds would not be affected by the increase in traffic volume.
This feature, combined with ultra-high speed operation, would achieve ultra-high
capacities without compromising mobility.
As for safety, the vehicle/roadway interface is not affected by small stones, rain, snow
and ice because the vehicles "float" above the roadway surface. Collisions between
vehicles are impossible because headways are automatically maintained by control
centers. Also, vehicles cannot escape laterally because both sides on the guideway are
controlled magnetically. Magnetic flux leakage from the vehicle-bomne superconducting
magnets can be reduced to safe levels through shielding.
The AVCS maglev guideway requires about the same space as a normal highway lane
and many existing freeway medians could accommodate two guideway lanes, one in each
direction. Many of the geometric design constraints imposed by the tire/pavement
interface can be eliminated.
AVCS maglev would be energy efficient since the power is produced in the main
power stations, while the internal combustion engine automobile carries its own power
station whose power generation efficiency is much lower. Furthermore, this power is
provided in the form of electricity which is increasingly less dependent on petroleum for
production.
AVCS maglev is a powerful means of limiting damage to the environment without
curtailing mobility. Where atmospheric pollution is concerned, exhaust gases from
automobiles and aircraft engines combine to produce five of the main noxious substances
including toxic nitrous oxide and lead, corrosive sulfur dioxide, carcinogenic
hydrocarbons, and carbon monoxide which affects oxygen supply and climate. AVCS
maglev would reduce the generation of these harmful substances substantially.
As the last feature, AVCS maglev will enhance mobility and reduce traffic congestion
substantially, cutting down the transportation cost of production significantly. At the
same time, AVCS maglev industry itself will become a huge industry and also will
stimulate other related industries.
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Figure 1. Principles of AVCS Maglev Levitation, Guidance and Propulsion
AVCS Maglev Vehicle Development Model
Overview
The AVCS Maglev Vehicle Development Model (VDM) is described in two
complementary forms of the system dynamics modeling, causal diagrams and DY NAMO
equations. The causal diagram not only portrays the cause and effect relationships
between the independent variables and dependent variables of VDM but also facilitates
writing DY NAMO equations which permit one to perform the computer simulation.
In a causal diagram, arrows describe the direction of causality between each pair of
variables, where the arrow can be interpreted as ‘affects’ and the sign, plus or minus,
indicates the type of relationship between the independent variable and the dependent
variable. Two types of arrow lines are used. Solid lines indicate physical flows between
the rate variables and the level variable, and dashed lines indicate information flows
between any other pairs of variables. “L” represents the level variables such as the
number of maglev vehicles and the weight of the superconductor-cryostat assemblies.
“R” represents rate variables such as the vehicle production rate, vehicle discard rate,
etc. The whole simulation process is illustrated in Figure 2.
nl 7 TAT ASSE GET Mu
VD VUM ADT WMSC A ~PATVWM HTSBM
VPR “MV- >VDR WRR HTSB
' '
ME AVE LIFETIME WoT MAGLE GT MAGLEY
wt CUE aOTOTTE OTD NULT
ALVM ~ALV WMSCP* WMSCPM
Figure 2. Causal Diagram for AVCS Maglev Vehicle Development Model
Model Description
The number of maglev vehicles (MV) increases by the production of vehicles and
decreases by the disposal of them. The vehicle production rate (VPR) depends on their
demand. The demand for the vehicles (VD) increases as the price of the vehicle (VP)
decreases and decreases as the price increases. The initial price of the vehicle is assumed
to be $260,000 in the year 2000 which is taken as the base year of the analysis.
However, this price will go down as more vehicles are produced and as the weight of the
vehicle reduces. The reduction of the vehicular weight will result mainly from the
advances in the high-temperature superconducting technology. The sales revenue from
the vehicles (REV) is decided by the price and the demand.
MV.K=MV J+DT)(VPRJK-VDRJK)
VPR.KL=VD.K
VD.K=VDN*VDM.K
VDM.K=TABHL(VDMT,VPN/VP.K,1,10,.6)
VDMT=.8/1.2/1.4/1.8/2.8/5.2/13.6/15.8/22/32/38/43/46.5/48.2/49.3/50
VP.K=V PN*VUM.K*VPCM.K
VPN=260000
REV.K=VPCD.K*VD.K
MV - MAGLEV VEHICLES (VEH)
VPR - VEHICLE PRODUCTION RATE (VEH/Y R)
VDR - VEHICLE DISCARD RATE (VEH/Y R)
VD - VEHICLE DEMAND (VEH/Y R)
VDN - VEHICLE DEMAND NORMAL (VEH/Y R)
VDM - VEHICLE DEMAND MULTIPLIER (DIM)
NOrPHSPerae
VP - VEHICLE PRICE ($/VEH)
VPN - VEHICLE PRICE NORMAL ($/VEH)
VUM - VEHICLE UNAVAILABILITY MULTIPLIER (DIM)
VPCM - VEHICLE PRODUCTION COST MULTIPLIER (DIM)
REV - REVENUE ($/Y R)
The vehicle discard rate (VDR) is inversely proportional to the average life-span of
the vehicle (ALV). Also, it is assumed that for ten years after the AVCS maglev system
is implemented, no vehicles are discarded. For this period, the vehicle will be quite
expensive, and thus the owners will try to keep it as long as possible. The initial average
life-span of the vehicle is assumed to be 15 years. As more vehicles are produced, the
price will become lower and the consumers will buy new vehicles more often.
wa
Hearraor
VDR.KL=CLIP(MV.K/ALV.K,0,(TIME.K-2000),10)
ALV.K=ALVN*ALVM.K
ALVN=15
ALVM.K=CLIP(ALVM2.K,ALVM1.K,(MV.K/MVN)/1E4,11)
ALVM1.K=TABHL(ALVMI1T,(MV.K/MVN)/1E4,1,11,2)
ALVMIT=1/.98/.97/.95/.93/.92
ALVM2.K=TABHL(ALVM2T,(MV.K/MVN)/1E4,11,211,50)
ALVM2T=.92/.90/.85/.80/.75
VDR - VEHICLE DISCARD RATE (VEH/Y R)
ALV - AVE LIFETIME VEHICLE (YR)
ALVN - AVERAGE LIFETIME VEHICLE NORMAL (YR)
ALVM - AVE LIFETIME VEHICLE MULTIPLIER (DIM)
The weight of the maglev vehicle is assumed to be 6,000 pounds initially. The
vehicular weight reduces as the weight of the superconductor-cryostat assemblies
(WMSCA) decreases. The weight of the superconductor-cryostat prototype (WMSCP),
which is assumed to be 1,200 pounds initially, reduces as the high-temperature
superconducting technology develops. The development of the technology is assumed to
depend on the amount of R&D budget (HTSB) allocated. HTSB will increase as the
demand for maglev vehicles increases.
A
HP PHprmr4>>
WMV.K=MAX(WMSCA.K/FATVW.K,3000)
FATVW.K=FATVWN*FATVWM.K
FATVWM.K=TABHL(FAVWMT,WMSCA.K/WMSCAN,0,1,1)
FAVWMT=.25/1
WMSCA.K=WMSCA J-(DT)(WRRJK)
WRR.KL=CLIP((W MSCA.K-WMSCP.K)/ADT,0,WMSCA.K,WMSCP.K)
WMSCP.K=WMSCPN*WMSCPM.K
WMSCPM.K=TABHL(WMSCPMT,HTSB.K/HTSBN,0,2,1)
WMSCPMT=2/.5/.25
HTSB.K=HTSBN*HTSBM.K
HTSBM.K=TABHL(HTSBMT,(VD.K/VDN),1,31,10)
HTSBMT=0/1/1.5/2
WMV - WGT MAGLEV VEHICLE (LB)
FATVW - FRACT ASSEMBLY TO VEHICLE WEIGHT (DIM)
FATVWN - FRACT ASSEMBLY TO VEHICLE WEIGHT NORMAL (DIM)
FATVWM - FRACT ASSEMBLY TO VEHICLE WEIGHT MULTPLIER (DIM)
WMSCA - WGT MAGLEV SC-CRY OSTAT ASSEMBLIES (LB)
WRR - WEIGHT REDUCTION RATE (LB/Y R)
ADT - ASSEMBLY DEVELOPMENT TIME (YR)
WMSCP - WGT MAGLEV SC-CRY OSTAT PROTOTY PE (LB)
WMSCPN - WGT MAGLEV SC-CRY OSTAT PROTOTY PE NORMAL (LB)
WMSCPM - WGT MAGLEV SC-CRY OSTAT PROTOTY PE MULT (DIM)
HTSBN - HIGH TEMPERATURE SC BUDGET NORMAL ($/Y R)
HTSB - HIGH TEMPERATURE SUPERCONDUCTING BUDGET ($/Y R)
HTSBM - HIGH TEMPERATURE SC BUDGET MULT (DIM)
Simulation Results
The simulation results are presented in terms of the vehicle price, demand, sales revenue,
and vehicular weight as summarized in Table 1.
Table 1. Simulation Results of AVCS Maglev Vehicle Development Model
Year Numberof Demand for Vehicle Veh. Price in Revenue Vehicle
Vehicles Vehicles Price Cur. Dollars Weight
MV (veh) VD (veh/yr) __ VP ($/veh) VPCD ($/veh) REV ($/yr)_ WMV (lb)
2000 100 0.32 M 260.0 T 260.0 T 83B 6,000
2010 44.5M 9.29M 44.3T 56.8T 528 B 5,161
2020 122.5M 17.83M 33.0T 54.4T 970B 3,813
2030 185.3 M 20.00 M 26.0T 55.0T 1,099 B 3,000
2040 210.2M 20.00 M 26.0T 70.5T 1411B 3,000
2050 218.9M 20.00 M 26.0T 90.5 T 1,811 B 3,000
Note: T =thousand, M = million and B =billion
The number of maglev vehicles reaches over 210 million in 2040, when the U.S.
population is 379.6 million persons according to the National Development Model.
There were 143 million automobiles in 1991, when the population was about 250 million
persons (U.S. Bureau of the Census, 1993; Economist Intelligence Unit, 1992).
The demand for maglev vehicles reaches 20 million veh/yr in 2040. The price of the
vehicle will be very high initially, but it will go down as more vehicles are produced. In
2040, the price will be $26,000 in the year 2000 constant dollars and $70,500 in the year
2040 current dollars. In the same year, PCI will be $108,200 according to NDM.
The revenue from the sales of maglev vehicles amounts to $1,411 billion, which
corresponds to 3.4% of GNP. People in the United States spent $184.1 billion for motor
vehicles and parts in 1991, when GNP was $5,673 billion (The Economist Intelligence
Unit, 1992).
The weight of the vehicle is projected to decrease down to 3,000 pounds from 6,000
pounds, provided that the high-temperature superconducting technology develops to the
full extent. These results are illustrated in Figures 3 to 5.
Figure 3. No. of AVCS Maglev Vehicles and Demand
Figure 4. Vehicle Price (in Constant and Current Dollars) and Vehicle Weight
Figure 5. Revenue from Sales of Vehicles
Conclusions
Based on the analysis presented herein, several conclusions could be derived as follows:
* The price of vehicle will go down as more vehicles are produced and as the weight of
the vehicle reduces. The reduction of the vehicular weight will result mainly from the
advances in the high-temperature superconducting technology. The development of
this technology will depend upon the amount of R&D budget allocated and the
amount of R&D budget will increase as the demand for vehicles increases. In 2040
the price of vehicle will be $26,000 in the year 2000 constant dollars and $70,500 in
the year 2040 current dollars. The revenue from the sales of maglev vehicles will
amount to $1,411 billion, which corresponds to 3.4% of GNP.
* The AVCS Maglev Vehicle Development Model illustrates the relationship among
important factors in reducing the weight and price of the vehicle. When the model is
developed more in detail, it will provide more information which can be utilized in
transportation policy-making process.
References
1. Economist Intelligence Unit, (1992). USA: Country Profile 1992-93, Business
Intemational Ltd., London, U.K.
2: Lee, S. H., (2002). “The Conceptual Development of an Innovative Hybrid
Personal Transportation System Utilizing AVCS and High-Speed Magnetic
Levitation Technology,” Transportation Planning and Technology, to be
published.
3.
U.S. Bureau of the Census, (1993). Statistical Abstract of the United States
1993.
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