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AGV nAvigation system based on flexible and innovatiVE UWB positioning

Final Report Summary - AGAVE (AGV nAvigation system based on flexible and innovatiVE UWB positioning)

Automatic guided vehicles (AGV) are designed to perform their operations without direct human guidance. They are used in a wide variety of industrial applications and usually can be laser, inertially or Cartesian-guided. An automatic guided vehicle system (AGVS) consists of one or more computer-controlled wheel based load carriers (normally battery-powered) that runs on the plant floor (or if outdoors on a paved area) without the need for an onboard operator or driver. AGVs have defined paths or areas within which or over which they can navigate.

The aim of this project was to provide a new guidance system based on ultra wide band technology, thus overcoming the main constraints of the classic guidance methodologies, such as the impossibility to drive a vehicle in non line of sight (NLOS) conditions or the inadequacy of the laser in harsh environments. The main breakthrough will be the possibility to drive an AGV in narrow aisles or, more in general, in NLOS conditions, without the need of installing a lot of beacons, exploiting the features of UWB technology that, thanks to the spread frequency spectrum of the emitted pulses, allows the penetration of the obstacles, showing a positioning accuracy both in navigation and in docking of about 1 cm.

Another important improvement of our AGV is the statistical error correction and data fusion technique based on Monte Carlo particle filter, that allows multiple inputs (odometry, DGPS, UWB, gyroscope for bearing and attitude determination) to feed the on board pc, giving a more reliable estimation of vehicle's position.

AGV can be the best horizontal transportation method for material handling in many applications. Summarised below are the benefits of AGVSs and the situations in which they are the best solution.

Low to medium throughput
In applications where the throughput relative to the distances travelled are in the low to medium range and do not warrant fixed path conveyor (25-100 loads per hour), an AGV system should be considered. Very low throughput can be best served with a manual delivery method such as fork lift trucks, while high throughput requirements are better suited for conveyor or towline.
- Zone containment of manual forklifts
Lifting stacking, and loading are functions best accommodated by manual forklift trucks. AGVs are better suited for horizontal transportation. In a properly designed system, forklift trucks are contained to specific areas of a facility (i.e. shipping dock or staging areas). An orderly systemised facility will not allow random disbursement of manual fork lift trucks over long distances.
- Consistent and stable loads
Applications where the load profile is relatively consistent are well suited for an AGV system. A common load footprint, which allows repeat interface by an AGV is a fundamental requirement.
Long distances -
The distance between load pickup and delivery points will influence the material delivery system solution. AGVSs are typically favoured in applications where distances between stations are approximately 200 feet or more. However, shorter distances can be justified if the vehicles are used as a bridge between two points.
- Steady and continuous throughput
In applications where material delivery requirements are steady, continuous, and repetitive shift after shift, AGVs can be the best solution. AGVs can respond well to steady, continuous flow because AGVs operate at fixed speeds and fixed operating cycles.
- Electronic dispatching of loads
Efficient scheduling and movement of loads can be accomplished with AGVs. Load movement scheduling can be queued in an efficient pre established manner (FIFO or prioritisation). AGVs can respond to calls for pickup and delivery; this improves material handling efficiency.
- Process automation
AGVs can be the best solution when scheduled material flow is required in to and out of manufacturing cells. Automated manufacturing and production systems operate most efficiently when tied together by an AGV.
- Sortation
AGVs provide an excellent horizontal transportation medium when many pickup and delivery points are required. AGVs have an advantage over a conveyor solution in these situations due to the complexity and cost of the latter solution.
- Need for Flexibility
If system expansion and system changes are anticipated, an AGVS may be the best solution. AGVs are more adaptable to change compared to other horizontal transportation methods such as towline, monorail or conveyor.
- AS / RS interface
AGVs offer an excellent transportation method when load movement in to and out of an AS / RS is required. AGVs scan interface at multiple storage aisle P / D points while keeping the interface points free of a fixed obstruction. AGVs also blend well with AS / RS because both are automated computer controlled systems. A manufacturing cell can request a load to be delivered out of storage to a station. The partnership between the AS / RS and the AGV allows for combined automated storage and horizontal transportation.

Wireless body area networks (WBANs) are another example of how our life could be influenced by UWB. Probably the most promising application in this context is medical body area networks. Due to the proposed energy efficient operation of UWB, battery driven handheld equipment is feasible, making it perfectly suitable for medical supervision. Moreover, UWB signals are inherently robust against jamming, offering a high degree of reliability, which will be necessary to provide accurate patient health information and reliable transmission of data in a highly obstructed radio environment. The possibility to process and transmit a large amount of data and transfer vital information using UWB wireless body area networks would enable tele-medicine to be the solution for future medical treatment of certain conditions. In addition, the ability to have controlled power levels would provide flawless connectivity between body-distributed networks. UWB also offers good penetrating properties that could be applied to imaging in medical applications; with the UWB body sensors this application could be easily reconfigured to adapt to the specific tasks and would enable high data rate connectivity to external processing networks (e.g. servers and large workstations).

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