2. • IT’S A PART OF ‘MATERIAL TRANSPORT SYSTEMS’
AND COME UNDER ‘VEHICLE-BASED SYSTEMS’.
• AGV IS A MATERIAL HANDELING SYSTEM THAT
USES INDEPENDENTLY OPERATED,SELF
PROPELLED VEHICLES GUIDED ALONG DEFINED
PATHWAYS.
TYPES OF AGV:
• DRIVELESS TRAINS
• PALLET TRUCKS
• UNIT LOAD AGVs
3. • First type of AGVS to
be introduced around
1954
• Common application
is moving heavy
payloads over long
distances in
warehouses and
factories without
intermediate stops
along the route
4. • Used to move
palletized loads along
predetermined routes
• Vehicle is backed into
loaded pallet by
worker; pallet is then
elevated from floor
• Worker drives pallet
truck to AGV guide
path and programs
destination
5. • Used to move unit loads from station to station
• Often equipped for automatic loading/unloading of pallets
and tote pans using roller conveyors, moving belts, or
mechanized lift platforms
6. • TWO GRAPHICAL TOOLS ARE USED FOR
DISPLAYING & ANALYSING THE DATA IN THESE
DELIVERIES:
1.FROM-TO-CHART
IT’S A TABLE THAT CAN BE USED TO INDICATE
MATERIAL FLOW DATA AND DISTANCES B/W
MULTIPLE LOCATIONS.
2. NETWORK DIAGRAM
THESE CAN ALSO BE USED TO INDICATE THE
SAME INFORMATION. IT CONSISTS OF NODES AND
ARROWS{INDICATE THE RELATIONSHIP B/W
NODES}.
IN MATERIAL HANDELING NODES REPRESENT
LOCATIONS{LOAD & UNLOAD STNS}, THE ARROWS
REPRESENT MATERIAL FLOW & DISTANCES B/W
7.
8. • MATHEMATICAL EQUATIONS CAN BE USED TO
DESCRIBE THE OPERATION OF VEHICLE BASED
MATERIAL TRANSPORT SYSTEMS.
• ASSUMPTIONS:
1.VEHICAL OPERATES AT A CONSTANT VELOCITY
THROUGHOUT ITS OPERATION.
2.IGNORING EFFECTS OF ACCELERATION,
DECELERATION, & OTHER SPEED DIFFERENCES THAT
MIGHT DEPEND ON THAT WHETHER VEHICAL IS
TRAVELLING LOADED OR EMPTY.
3.THE TIME FOR TYPICAL DELIVERY CYCLE CONSISTS OF:
• LOADING AT THE PICKUP STN.
• TRAVEL TIME TO THE DROP-OFF STN.
• UNLOADING AT THE DROP-OFF STN.
• EMPTY TRAVEL TIME OF VEHICLE B/W DELIVERIES.
9.
10. • THE T(C) CALCULATED MUST BE CONSIDERED AN
IDEAL VALUE, AS IT IGNORES ANY TIME
LOSSESDUE TO RELIABILITY PROBLEM, TRAFFIC
CONGESTION & OTHER FACTORS THAT MAY SLOW
DOWN A DELIVERY.
• NOT ALL DELIVERY CYCLES ARE SAME.
ORGANISATIONS AND DESTINATIONS MAY BE
DIFFERENT FROM ONE DELIVERY TO THE NEXT.
WHICH WILL AFFECT L(D) & L(E) TERMS.
• SO THESE TERMS ARE CONSIDERED AS AVERAGE
VALUES FOR LOADED & EMPTY DISTANCES
TRAVELLED BY THE VEHICLE.
• WE CAN CALCULATE TWO PARAMETERS-
1.RATE OF DELIVERIES PER VEHICLE
2.NO. OF VEHICLES REQUIRED
11. • THE POSSIBLE TIME LOSSES INCLUDE IN AGVs-
1.AVAILABILITY(A)
IT’S A RELIABILITY FACTOR DEFINED AS
PROPORTION OF TOTAL SHIFT TIME THAT THE
VEHICLE IS OPERATIONAL & NOT BE BROKEN
DOWN OR BEING REPAIRED.
2.TRAFFIC CONGESTION
‘TRAFFIC FACTORF(T)’ IS CONSIDERED FOR THIS
PURPOSE.
IT INCLUDES-
• WAITING AT INTERSECTIONS
• BLOCKING OF VEHICLES(MAINLY IN AGVs)
• WAITING IN A QUEUE AT LOAD/UNLOAD STN.
12. • IF THESE SITUATIONS DO NOT OCCUR THEN
F(T)=1.
• AS BLOCKING INCREASES, VALUE OF F(T)
DECREASES.
• WAITING AND TRAFFIC IS AFFECTED DUE THE NO.
OF VEHICLES IN USE IN SAME PATH ETC.
• IF THERE IS ONE VEHICLE, THEN NO BLOCKING
SHOULD OCCUR, AND THE TRAFFIC FACTOR WILL
BE 1(ONE).
• TYPICAL VALUES OF TRAFFIC FACTOR FOR AN
AGVS RANGE FROM 0.85 TO 1.0.
13. • AVAILABLE TIME-
AT = 60 * A * F(T) * E(W)
WHERE,
AT-AVAILABLE TIME E(W)-WORKER EFFICIENCY
A- AVAILABILITY F(T)-TRAFFIC FACTOR
• RATE OF DELIVERIES PERVEHICLE-
R(DV) = [AT/T(C)]
WHERE,
R(DV)-HOURLY DELIVERY RATE/VEHICLE
T(C)- DELIVERY TIME
14. • WORKLOAD-
IT IS DEFINED AS THE TOTAL AMOUNT OF WORK,
EXPRESSED IN TERMS OF TIME, THAT MUST BE
ACCOMPLISHED BY THE MATERIAL
TRANSPORTSYSTEM IN 1 HOUR.
WL = R(f)* T(C)
WHERE,
R(F)-SPECIFIED FLOW RATE OF TOTAL
DELIVERIES/ HOUR FOR THE SYSTEM
