Navistar selected Jervis B. Webb to supply the integrated AGV/Conveyor material transportation system. It includes 103 pickup and delivery stations.
The customer was able to phase installation of the inertially-guided AGV system over a four-year period in conjunction with increases in their production schedule.
The system provides just-in-time delivery of raw material to specific locations in manufacturing and assembly, consolidates staging of material to the dock area for better material control, and allows offshift re-stocking of production material.
Each of seven AGVs is equipped with a two level powered roller conveyor loadbed capable of transferring a full load on its upper level and an empty container/pallet on the lower level. The vehicles are also capable of transferring an empty container/pallet on the upper level if required. The vehicles have a maximum load capacity of 4,000 pounds.
The Vehicle System Manager (VSM™) which communicates with the AGVs via FM radio, performs traffic vehicle management, monitors delivery requirements at conveyors via a plant-wide modbus network, and initiates load movements within the system. Powering the VSM is a DEC MicroVAX 3100 Model 40.
When loads are to be transported to a specified area, the VSM directs the appropriate vehicle to perform the
operation. Because system uptime is critical, the VSM has a hot backup computer system. This system transfers control to a backup computer to maintain system performance and control, in the event of a primary computer failure.
Vehicle control and inertial guidance is managed by a solid state gyroscope and SmartMark™ landmark codes that accurately maintain the AGV's path of travel throughout the "virtual" guidepath in the system.
The VSM monitors battery status messages from each vehicle in the system, and sends vehicles to the battery exchange area when needed.
The conveyor system includes chain driven live roller, pallet accumulators, shuttle carts, lift and tilt devices, and chain transfers.
Dual-height heavy-duty roller conveyors are located at many of the pick/drop stations to allow empty and full load exchange with a single automatic guided vehicle.
To facilitate installation and minimize plant changeover time, all conveyor equipment was delivered pre-assembled, wired, and tested.
AGV System Benefits
- Effective inventory tracking and control interfaced with material handling system
- Reduced material handling costs and product damage when compared to manual means of product transport
- Increased material throughput capacity
- Non-wire inertial guidance navigation system provides flexibility to easily relocate pick/drop stations or expand the system
- Reliable, flexible control architecture
- Vehicle System Manager (VSM) software continuously monitors, directs, and coordinates vehicle operations via continuous, radio communications link
Auto-Trans Vehicle Features
- Inertial Guidance and SmartMark
™ Location Sensing
Bi-directional Automatic Travel
Dual Side Conveyor Transfer (dual level)
On-board Microcomputer
32-Character Display and Keypad
Continuous Radio Communication
Emergency Bumpers and Remote Object Detection
Highly Accurate Speed Control Over Battery Operating Range
Vehicle Specifications
- Max.Travel Speed (loaded) ..... 180 Feet Per Minute
Load Capacity (maximum) .......................... 4,000 lb
Load Description ..................... Multiple Size Pallets
Stopping Accuracy ........................................... +/-1"
Vehicle System Manager
Software:
- Vehicle Traffic Control and Blocking
- Vehicle Routing and Dispatch
- Color Graphics Monitoring
- Real-time FM Radio Communication
- Hot Backup VSM Computer
Hardware:
- DEC MicroVAX 3100, Model 40
- DEC 423 Interface Board
- Color Graphic Terminal
- Factory Modem
- Printer
- Operator Pushbutton Call Station
- Webb Heavy-Duty Pallet Accumulation Conveyor Stations, Chain Transfers, Chain Driven Live Roller Conveyor, Shuttle Cars, and Tilt Stations at over 100 Operator Work Stations
