Presentation Transcript

1. Material’s HandlingAutomated Guided Vehicles(AGVs)

   10/28/2009 Britton Nilsen
2. What are AGVs Automated Guided Vehicles (AGVs) are vehicles that are equipped with automatic guidance systems and are capable of following prescribed paths. Unlike traditional robots, AGVs are not manipulators, they are driverless vehicles that are programmed to follow a guidepath. In automated factories and facilities AGV's move pallets and containers. In offices they may be used to deliver and pick up the mail. They are even used to transport patrons around in airports. http://www.youtube.com/watch?v=6VU6Ygk21ww http://www.youtube.com/watch?v=Yayaet55okU&feature=related
3. Current State
4. Uses AGVS Towing Vehicleswere the first type introduced and are still a very popular type today. Towing vehicles can pull a multitude of trailer types and have capacities ranging from 8,000 pounds to 60,000 pounds.[9] AGVS Unit Load Vehiclesare equipped with decks, which permit unit load transportation and often automatic load transfer. The decks can either be lift and lower type, powered or non-powered roller, chain or belt decks or custom decks with multiple compartments. AGVS Pallet Trucksare designed to transport palletized loads to and from floor level; eliminating the need for fixed load stands. AGVS Fork Truckhas the ability to service loads both at floor level and on stands. In some cases these vehicles can also stack loads in rack. Light Load AGVSare vehicles which have capacities in the neighborhood of 500 pounds or less and are used to transport small parts, baskets, or other light loads though a light manufacturing environment. They are designed to operate in areas with limited space. AGVS Assembly Line Vehiclesare an adaptation of the light load AGVS for applications involving serial assembly processes.
5. Costs Rent for $6000/month (whereas for 3 forklift operators it would cost $12,000/month) http://www.ndcta.com.au/costing.html
6. Supporting Technology Vehicle Guidance Guide Tape Wired Laser Target Gyroscopic Traffic Control Zone Control Forward Sensing Control Combination Control System Management Programming software and user interface
7. Applications Diverless trains Pallet trucks Unit load carriers Driverless train operations Storage/distribution systems Assembly line operations Flexible manufacturing systems Miscellaneous applications (sensitive waste, mail, etc.) Repetitive movement of materials over a distance Regular delivery of stable loads Medium throughput/volume When on-time delivery is critical and late deliveries are causing inefficiency Operations with at least two shifts Processes where tracking material is important
8. Rules ANSI B56.5 Safety Standard for Guided Industrial Vehicles and Automated Functions of Manned Industrial VehiclesANSI B56.5 defines safety requirements for powered, unmanned automatic guided industrial vehicles. The standard requires that the users are responsible for all factors affecting the operation and maintenance. This responsibility includes load stability and marking the travel path on the floor, including turning and maneuvering clearances. There are also requirements for manufacturers. Deviation from the travel path of more than 3 inches for an external reference (e.g. guide wire), or, more than 6 inches for inertial guidance system shall, require an emergency stop. A loss of speed control also requires an emergency stop. Vehicle warning indicators, audible and/or visual, shall operate when the vehicle is in motion. Emergency controls are required which would stop the vehicle if there is a loss of speed control, loss of guidepath reference, or an object is detected in the direction of travel. Accessible emergency stop switches are required on the vehicle itself. Proximity Laser Scanner and Laser Scanner Interface (PLS/LSI) TechnologyA Proximity Laser Scanner (PLS) creates a sensing field with a pulsed light that is reflected off of a rotating mirror so that it is transmitted in a 180 degree pattern. When an object enters the sensing field, the light is reflected back to the PLS. The distance to the object is computed using the time interval between the transmitted pulse and the reflected pulse, and, the angle of the rotating mirror. The sensing field is divided into three areas; safety zone, warning zone, and surveyed zone. The surveyed area is the maximum radius surveyed by the PLS. When the PLS determines that an object is on the safety zone, hazardous motion is stopped. When an object is detected in the warning zone, it initiates a warning or an avoidance maneuver. Laser BumpersTMSICK's Laser BumperTM technology uses PLS/LSI technology to provide a non-contact means for object detection. This advanced system permits increased speed and productivity because the size and shape of the stopping/slow-down/warning zones can be adjusted in real time depending on speed and the load. The protective area can be automatically extended on the sides of the vehicle when turning corners. Vehicle speeds can be increased in straight, unobstructed paths for improved productivity. Response times are as low as 60 ms depending on the system. AGVs equipped with the Laser BumperTM do not have to hit an object or person to stop. Worker apprehension about whether the AGV is actually going to stop, after contact is made is eliminated. Injuries due to workers trying the beat the AGV are eliminated because the AGV will adjust speed, and stop if necessary, as a person moves in and out of the sensing zones. Safety Guidelines for Employees and ContractorsAGV travels paths should be clearly marked and should be kept clear of material. Employees should be trained not to ride the AGVs. Training should also include instructing personnel to stay clear of an approaching AGV. Weighed cones or other portable obstacles can be placed where workers may be working on or near an AGV travel path. The training program should also include contractors that may come into a plant or warehouse to perform work.
9. Limitations Battery life is a limitation 8-12 hours to charge 5-10 minutes to manually change battery Exist no passing zones due to size of robots Programming limitations AGVs are not as versatile as humans AGVs are slow due to safety concerns
10. Primary Vendors of Technology JBT corporation Chicago, IL NDC Technology Australia Chatswood, Australia Egemin Automation Holland, MI
11. Existing or Evolving Standardssee Safety Standards under “Rules”
12. Summary AGVs usually pay for themselves in the long run. They replace repetitive manual labor They increase production Safety Standards AGV travels paths should be clearly marked, including turning areas. Workers should be trained to watch out for AGVs and to keep clear of an AGV path if a vehicle is approaching. Companies should provide similar training for contractors that may be working in their plant. Weighted safety cones should be placed around a work area when working on or near an AGV travel path. "Virtual" bumper systems can increase productivity and system flexibility. Improve plant safety with regard to object detection/avoidance.
13. References http://en.wikipedia.org/wiki/Automated_guided_vehicle http://www.asse.org/ http://www.jbtc-agv.com/ http://www.mhia.org/