NDC developed and prvided by Kollmorgen is a generic, complete and scalable system that suits all types of automated
guided vehicles from small and simple to big and complex. As RUSSELL ROBOTICS is a member of Kollmorgen partner group,
we serves not only supply of AGV system but also training service for NDC solution.
NDC works with all established navigation technologies. Advanced navigation technology Natural navigation
introduced above video, is a concept for navigation in the existing environment. By using Natural navigation
there is no need to install reflectors and markers, leading to lower commissioning costs.
NDC gives you access to a set of effcient design and service tools. The design tools helps you outline all kinds of layouts
as well as system and vehicle applications. Service tools include vehicle maintenance (e.g. fault-training, statistics and
software downloads) and automatic surveying of the environment.
NDC hardware consists of powerful and reliable components in a number of areas. All components are designed
for tough environments where vibrations, dust, moisture and temperature vibrations are all part of daily life.
End-users require high uptime, efficient daily operations and applications that are easy to change.
we help you meet these demands with NDC services. Our service portfolio consists of training service, support service
and consulting service.
RUSSELL ROBOTICS has supplied varoius type of AGVs that are controlled based on PLC solution.
The great advatage of PLC soultion is to provide maintenance personnel with easy-accessible control environment.
When PLC is used as vehicle controller, it controls all driving performance of vehicle by interfacing with navigation sensors
and supervises all main components for safety and loadhandling.
.
ACU 1000 Series has been developed by RUSSELL ROBOTICS and this solution provides specialized controller for driving
control purpose only, supports all floor based guidance methods and various driving patterns as well as other solutions.
In case that complicated load handling or other functios are required, those can be achived by using auxiliary controller, PLC.
Also one integrated design tool provides environment to create vehicle apllication easily and diagnostic functions as well.
VEHICLE CONTROLLER
SPECIFICATION
- Floor based guidance
- Supports all vehicle types
- Supports all driving patterns
- Max. 48m/min speed
- ± 10mm stop tolerance
- Programmable laser bumper
- Manual control device
- Graphical operator interface
FEATURES
- 32-bit RISC processor
- Linux operating system
- RS - 232 · 422 · CANbus
- All OK relay
- SD card reader
- LED Indicators
- Protection for reverse polarity
- Protection for over voltage
All vehicles can drives in both forward and reverse directions on the straight path and even curves as well.
However, please note that a SD(steer drive) vehicle runs much like a car on the curves when planning the AGV layout.
It means that SD vehicle has to 'over shoot' in order to keep the reference point over the deigned path through curves.
On the other hand, QUAD vehicle follows curves without 'over shoot' as it has a reference point on the center line generally
.
On a 'Diff' segment the vehicle steers by speeding up one wheel and slowing-down the other, the vehicle will always turn towards the side of the slower traveling wheel. Notice that the drive wheels never change angle while the vehicle is moving through the curves. Also this driving mechanism used when AGV moves to the side as wheel is being rotated 90 degrees .
Transports in the system are handled as orders.
Most of the time an order is a transport between
two pre-defined position or stations.
Once an order is started it will run a transport
procedures predefined by system designer
on the AGV control system.
Generally, transport order needs to be generated
automatically using one of following ways.
A. Push-button or sensor
pushing the button or trigger of the sensor bit makes
a transport start. usually they are connected to the
AGV control system directly or via I/O module.
B. Host System
The host system such as MES, WMS and ERP will send
a message to the AGV control system to start a transport
sequence using specified communication protocol over the network.
Once an order was generated, AGV control system finds the most suitable vehicle for a transport and finds the fastest way
to the destination. If there are more than one type of vehicle in the system, AGV control system will look for the vehicle type
that can handle this specific order. If there are no suitable vehicle free to handle the order, it will be put in a pending queue.
If there are more than one suitable free vehicle, the vehicle that is closest to the pick-up station will be choosen.
Once an order was completed, AGV communicates that order was completed sucessfully to AGV contol system.
Then if necessary, AGV control system reports order completion to process control system as well.
Transport sequence is repeated from order generation to order completion continuously while process is operating.
Sometimes an order can be finished unsucessfully by unexpected situation so that AGV control system is designed
to be able to handle many of the exception that can occur in transport sequence.
For example, if cancellation of an order was happened, AGV control system finishes the order immediately and makes
AGV do proper action programmed case by case.
In order to make the traffic flow as effective as possible, it is recommended to design the layout to have two-way path
so that vehicles are able to avoid collision with each other while driving. However if there is a place where vehicle needs
to drive on the single path or a crossing, AGV control system must determine which vehicle should drive first at there.
This is called as traffic management.
When there is a move command for a vehicle,
the AGV control system allocates segments where
vehicle drives and note that occupied segments
to prevent other vehicles from driving into there.
When two or more vehicles are blocking each other,
a deadlock situation may have occurred.
when such situations are detected by AGV control
system,it tries to solve the situation by re-routing
one or more of the vehicles.
To avoid traffic jams, traffic rules should be decided from the design phase.
Followings are general traffic rules applied in the single path area or crossing section.
However it is not necessary to keep them since system can be developed as being optimized with consideration of operting
conditions and system requirements.
- ·The first arrived vehicel has a priority for driving.
- ·The vehicle which is allocated for a good transport order.
- ·The vehicle which is executing an order currently.
- ·The vehicle which is loading a good.
- ·The vehicle which is transporting a good of higher priority.
Below figure shows the data flow between components in AGV system including interface data flow with Process Control
System.Generally, wireless communication is used for data transmission between AGV Control System and vehicles.
On the other hand, Ethernet is used for data transmission between AGV Control System and other contorl systems.
In some cases, AGV system needs to be interfaced with auto-door, conveyor and other equipment in the factory directly.
The digital inputs are usually used to indicate current operational status of equipment then AGV control system requests
for conditional operations to the equipment by changing the status of digital outputs.
If there is equipment on the AGV path, AGV control system interfaces with it to make AGV path through there.
After AGV leaves there, AGV control system interfaces again to withdraw request.
In case that load handling can be achived by operation of equipment at the station together with,
AGV control system does handshake to progress sequentional load handling steps.
Sometimes vehicle can handshake with equipment directly for load handling.
In order to avoid collision between AGV and equipment located nearby where AGV drives or operates for load
handling, AGV control system interfaces with it to request for stop of operation till AGV leaves there for safety.
There may be not only AGV control system but also other control systems in automated factory.
Therefore sometimes AGV control system is reqiured to interface with them for various purposes like order generation,
load handling, safety and so on. There is no fixed way to interface with them. Any method can be applied according to
communication requirements.
When database is used for interface, specified table is
created to share current operating information mutually.
Once one system updated information, the other system
recognized it by reading db table in regular time interval.
Another interface method is to communicate each other via
a message written in predefined data type protocol.
A message is sent when event is generated or in regular time
interval to notify updated information to the opponent.
Digital input and ouput can be used for interface as well.
Since systems communicates through connected I/O devices
directly, all shared information can be updated immediately.