AGVs right for FMCG job
June 1st 2011 Palletised raw materials and packaging tackled by AGVs from E&K Automation at UK
manufacturer of fast moving consumer goods
An analysis carried out by specialist manufacturer E&K
Automation compared forklift and conveyor based AGV
concepts and mixed fleets. It was concluded that for a
robust, reliable, flexible and resilient transportation system that
can automatically handle both 1,200 x 1,000 mm Chep pallets
and 1,200 x 800 mm Euro pallets at floor level and at various
conveyor heights, the use of two E&K Compact CBI-800
counterbalance fork lift AGVs was optimal.
Each of the two AGV systems deployed used seven laser-guided
vehicles of compact counterbalance design. Both AGV systems are
independent of each other, although any vehicle can be deployed
to work on either system for maximum resilience and flexibility.
This truck format allows pallet transfer positions to be passive,
leaving floors clear and free from powered conveyors. It also
avoids frames that would otherwise be needed to support a pallet
stacker AGV format and wide aisles that would be needed with a
straddle stacker AGV.
The counterbalance design also means that palletiser conveyor
interfaces do not need to be modified to accept the narrow or
wide load-wheel-arms that come with pallet stacker or straddle
stacker AGVs.
Operation
In essence, both AGV systems at the FMCG factory are designed
to take palletised raw materials and packaging from a conveyor
system in front of the warehouse to around 85 passive floor
positions in the production areas. Surplus material and finished
product from central palletiser conveyors are returned into
storage, while waste is taken to a compactor. Positioning accuracy
of the vehicles relative to each pick or drop location is ± 10mm.
There are three levels of control. In normal mode, vehicles
operate automatically under central AGV control. In semiautomatic
operation, they can be given instructions through onboard
or remote terminals. If operated by hand, the AGV is
driven and steered manually via its joystick control, with load
handling effected by push button.
Vehicle navigation is by E&K's NAV830 laser triangulation
system, which allows even the most complex AGV route including
load pick and drop positions to be simply created on a CAD
workstation and modified afterwards if necessary. Laser
navigation reflectors are fixed to elevated positions on walls,
columns or racking. Simulation tools help to optimise the routes,
select the optimum number of vehicles and check for conformity
with European standards. EK-REPORT provides user-friendly
presentations for analysing operating and performance data.
Safety
Although the factory and warehouse aisles of the manufacturer
are not defined as hazardous, there are safety issues.While the
low risk of explosion did not warrant fitting on-board gas
detection and shutdown equipment to each of the AGVs, they
are all interlocked with factory-wide fire and gas alarm systems
and interact with a number of automatic doors.
It was also considered expedient to incorporate features on the
vehicles to lessen the chance of product damage that could result
in gas being leaked into the warehouse or factory aisles, as well as
other measures to guard against ignition of any leaked gas that
may be present.
E&K Automation fitted AC motors to power the drive, steer
and lift on the battery powered vehicles, avoiding DC motors with
their potential risk of sparks from the brushes. To maximise safety
during travel, three laser scanners are employed, one at the front,
one at the rear and another at high level to detect obstacles on the
circuit. Electrically conductive tyres are employed to aid the
dissipation of static electricity.
To ensure the AGV knows the precise position of its forks when
a pallet is transferred or transported, two rotary encoders are
fitted on the lift mast, rather than the normal one. Additionally,
each fork tip includes a photoelectric sensor and there's a further
sensor on the forks carriage to detect that the pallet is fully on
board the AGV.
Three battery charging bays have been provided in each AGV
system to automatically top up vehicle power. In some AGV
environments, charging contacts are set into the floor but in this
installation, they are mounted on the wall. This approach avoids
having the battery contacts close to any leaked gas that might
collect at floor level and also removes the need for disruptive
building work.
In addition to the obstacle-detecting laser scanners at front and
rear, pressure-sensitive strips stop the vehicle immediately an
obstruction in the AGV's path is touched.Multi-colour status
lamps, amber turn-indicator lamps, two types of audible warning
device and four emergency stop buttons are standard equipment.
About 70 pallets per hour are transported by each system, 24x7,
and pallets weigh up to 1.25 tonnes. The AGVs drive at speeds of
up to 1.5 m/s, travel up and down ramps and cross a roadway, so
safety is paramount.
Summing up the benefits of the installation, Peter Holdcroft,
managing director of E&K in Bramley, Hampshire pointed to the
importance of automation in allowing Western economies to
compete with low-wage countries.
He added: "The flexibility of our latest AGV systems makes
them future-proof, enabling extensive modification, upgrading
and extension of capacity as
circumstances dictate." More articles from E & K Automation Ltd: | 
