Automated Guided Vehicles (AGVs): approach, advantages and examples
Automated guided vehicles – AGVs for short – have long been established in modern factories. Once installed, they take over automated tasks in the plant and ensure an efficient flow of materials. One component of the automated guided vehicle system is a driverless transport vehicle (AGV). These transport pallets, skeleton containers or small load carriers. On the other hand, an AGV consists of load transfer and load takeover stations. The AGVs are navigated by inductive or optical line guidance or freely by laser scanners with or without reflectors. The operation of AGVs takes place in the so-called cab mode (source and sink flexible depending on the order), flow line mode (same sequence of sources and sinks, mainly for assembly activities) and in mixed forms. An AGV can be taken out of the system and brought in, e.g. when it has to be loaded. The AGV receives its orders via a central master control or directly at the vehicle. The vehicle is in constant communication with its environment via its master controller and thus ensures, for example, that the gates are opened.
What are the advantages of a driverless transport vehicle?
Automated guided vehicles bring many advantages compared to traditional manual material handling equipment such as forklifts or fixed conveyor systems:
- Support for repetitive activities such as driving from A to B
- High availability around the clock
- More transparency through defined travel routes and times
- Reduced risk of accidents due to high safety standards
- Reduction of personnel costs
- Full flexibility due to routes that can be changed at any time
- Constant and low throughput times
- Minimization of transport damage and incorrect deliveries
What is the procedure for planning an automated guided vehicle system?
The planning of an AGV begins with the conceptual design. Here, the requirements for the transport task to be conceptualized are collected. The requirements for the description of the transport task are defined in the guideline VDI 2710. The requirements can be taken from the following illustration:
What are the possible AGV solutions in the market?
After the conceptual design has been completed by listing the requirements for the AGV, these are compared by Bross & Partner with a market overview. An excerpt of AGVs from established manufacturers such as Linde, Jungheinrich, KUKA, Gebhardt, DS Automotion, EK Automation or Still can be found in the following overview.
What costs and investments need to be considered in the business case?
In a business case, the investment level is compared with the annual savings potential. Therefore, we first look at the investment side. In addition to the acquisition costs of the AGV itself, an enormous planning effort must be factored in with the installation of an AGV. In particular, the planning of the route network is costly. This planning effort must definitely be included in the investment calculation. In addition to the costs for the AGV, the costs for the other system components, consisting of the load transfer stations and the AGV control system, must also be considered. Ongoing costs include operating costs for energy and maintenance. The savings potential of a monetary nature weighs most heavily on personnel costs. In addition, an AGV brings many other potential savings in terms of time, such as a reduction in throughput time. In addition, there is no need for personnel planning, for example for forklift drivers.
Load-pulling AGVs (e.g. tugs)
Load-bearing AGV (e.g. with fork )
Load-bearing AGVs (e.g. with lift table)
How safe are automated guided vehicles?
AGVs are equipped with comprehensive sensor technology. Sensors mounted all around enable protection in every direction in all operating modes. Personal protection scanners in the drive direction, side scanners and personal protection scanners in the load direction provide non-contact safety all around the vehicle. The scanners create two virtual fields around the AGV, the warning field and the protection field. If a person is detected in the warning field, the AGV reduces speed quickly in milliseconds. If a person enters the narrower protective field, the AGV stops immediately. The protective fields are dynamic, they adapt to the current speed of the AGV. The higher the speed, the wider the warning and protective field. And the AGVs even react to surprising indications as they scan the travel path. The AGV is also prudent in its own behavior. It emits visual and acoustic signals, for example, during the loading process. The automated hauler emits an acoustic signal before continuing and then travels at reduced speed for the first few seconds. This gives the operator enough time to move away from the trailers. The AGV always uses the same travel paths, which are not deviated from. If the travel path is used by the AGV and personnel at the same time, increased path widths must be used. Ground markings and corresponding warning signs must not be missing, of course.
What rules of conduct apply when working with AGV’s?
Despite the many safety features built into an AGV, it is important to minimize the risks through your own behavior. For smooth cooperation, the AGV comes with a few rules:
- Driveways must be kept clear
- Never step directly in front of the AGV into the travel path
- The AGV always has the right of way to work efficiently
- Always remain outside the danger zone during the charging process.
- Elevated things cannot be detected by the sensors and must not protrude into the travel path