12-08-2013, 03:40 PM
AUTOMATIC GUIDED VEHICLE FOR MATERIAL HANDLING SYSTEM
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ABSTRACT
Automated guided vehicles (AGV) are one of the greatest achievements in the field of
mobile vehicles. Without continuous guidance from a human they navigate on desired
path thus completing various tasks, e.g. product transportation inside manufacturing
firm. Though most of the presently the AGV work in a retrofitted environment, work
space as they require some identification for tracing their guide path, works are going on
developing such AGVs which are dynamic in sense of navigation and whose locomotion
is not limited to just a retrofitted workspace. The aim of this work was developing such a
natural feature AGV which takes visual input in the form signal and gains detailed
object, obstacle, landmark, identification to decide its guide path. The AGV set up
developed, used a commercial electric motor based car chassis which was fitted with
sensors to take real time input and resolve it using segmentation and image processing
techniques to reach a decision of driving controls. These controls were communicated,
or better imparted to vehicle using parallel port of computer to servo motors, which in
turn controlled the motion of vehicle. The work was focused more on dynamically
controlling the vehicle using refinement of driving mechanism (hardware), however it
could be assisted using better segmentation and obstacle detection algorithm. The results
could be enhanced if a better stereoscopic camera were used with a dedicated CPU with
better graphics capability.
INTRODUCTION
A material-handling system can be simply defined as an integrated system involving
such activities as handling, and controlling of materials. Materials include all kinds of
raw material, work-in-progress, sub-assemblies, and finished assemblies. The main
motto of an effective material-handling system is to ensure that the material in the right
amount is safely delivered to the desired destination at the right time and at minimum
cost. It is a Fundamentals of CIM integral part of any manufacturing activity. Role of
AGVs have become strategic with respect to the modern material handling practices
followed in the present day industry. The primary goals of today‘s automation
technology are productivity and flexibility, which can only be achieved in fully
integrated manufacturing environments. In this required integration a carefully
designed and efficiently managed material handling system is of crucial importance.
Automated guided vehicles (AGVs) are among the fastest growing classes of
equipment in the material handling industry. They are battery-powered, un- manned
vehicles with sensing capabilities for path selection and positioning. They are capable
of responding readily to frequently changing transport patterns, and they can be
integrated into fully auto- mated intelligent control systems. Automated guided vehicles
(AGVs) are being increasingly used for material transfer in production lines of modern
manufacturing plants.
Raw Material Handling
AGVs are commonly used to transport raw materials such as paper, steel, rubber, metal,
and plastic. This includes transporting materials from receiving to the warehouse, and
delivering materials directly to production lines.
Work-in-Process Movement
Work-in-Process movement is one of the first applications where automated guided
vehicles were used, and includes the repetitive movement of materials throughout the
manufacturing process. AGVs can be used to move material from the warehouse to
production/processing lines or from one process to another.
Pallet Handling
Pallet handling is an extremely popular application for AGVs as repetitive movement
of pallets is very common in manufacturing and distribution facilities. AGVs can move
pallets from the palletizer to stretch wrapping to the warehouse/storage and/or to the
outbound shipping docks.
AUTOMATIC GUIDED VEHICLES
AGVS is a material handling system that uses independently operated, self-propelled
vehicles guided along defined pathways. They are powered by on-board batteries.
AGVS is appropriate where different materials are moved from various load points to
various unload points Automated guided vehicle systems (AGVs), commonly known as
driverless vehicles, are turning out to be an important part of the automated
manufacturing system. With the shift from mass production to mid-volume and mid-
variety, flexible manufacturing systems, are increasingly in use. They require not only
machine flexibility but also material-handling, storage, and retrieval flexibility. Hence,
the importance of AGVs has grown in manifold. It is a battery-powered driverless
vehicle with sensing capabilities for destination, path selection, and positioning. The
AGVs belongs to a class of highly flexible, intelligent, and versatile material-handling
systems used to transport materials from various loading locations to various unloading
locations throughout the facility. The capability related to collision avoidance is nicely
inbuilt in AGVS. Therefore, the vehicle comes to a dead stop before any damage is
done to the personnel, materials, or structures.
GYROSCOPIC NAVIGATION TYPE
This navigation system utilizes an inertial guidance mechanism. Transponders are
embedded in floor and the slightest change in orientation of the vehicle is traced and
corrected accordingly by the gyroscope. The transponders in the floor are connected to
the computer system, controlling the direction rectified. Deviation from ideal track is
hardly 1 inch.
CONCLUSION
Automated guided vehicle systems are particularly useful in material handling in
manufacturing systems. Along with their increasing use, design problem of AGV
systems has been a major concern of study. Simulation is widely used to evaluate the
system performance for both real and proposed AGV systems. Many attempts have
been made for developing AGV simulators either for specific problems or as generic
applicable to any AGV system--simulators. However, there is still a strong need for a
generic and extensible (by using object oriented programming approach) AGV
simulator with broad capabilities. Hence, future research efforts can be directed to
create such simulation systems.