Implementing an AGV System

Concepting

This is the time when various system approaches are investigated. System requirements are defined such as throughput, load sizes, weights, and physical and control interfaces. Various system concepts are evaluated with respect to risk, cost, benefit, and functional compatibility in the operating environment. Out of this process a single concept is usually pursued in the design stage.

Less is More

One of the most common pitfalls in concepting systems is trying to accomplish too much. Often this results in a project, which is more difficult to implement, and which actually accomplishes less than planned. Some examples of trying to do too much are:

• System must handle all types of loads.

Maybe the most difficult load to handle occurs only two percent of the time. Does it really make sense to complicate the system with a lot of non-standard controls or mechanical designs for such a small number of loads? Not when considering the problems that can result compared with using standard equipment and designs for 98% of the loads. You should pursue alternate ways to handle the difficult loads without the AGVS system.

• In the future we want to be able to stack loads, etc.

Few systems use AGV fork lifts to stack loads. Yet many customers start out with this feature, or similar ones, on their wish list. In most cases, this is unrealistic. First, there are usually lower risk alternatives. Second, the AGVS systems will almost never utilize these features in the future.

Stacking loads is a nice feature, but is it practical? Not very. Are your loads easily stackable now and are they very stable? Does the double stack load make it necessary to buy a bigger AGV with more capacity? Many costs are involved in trying to accommodate possible "in the future" functions. You’ll have to make more space for a bigger vehicle now; it will likely run slower, cost more and be more complex. And it is likely you’ll never utilize the future features at all or at least the way you thought.

Look Before you Leap

The AGVS market is built on nearly 50 years of successful systems with sound methods that are proven in field use. Perhaps the most important step that can be taken in the concepting stage is to see AGVS systems that employ similar equipment and methods or are in similar applications. Talk to users. What has been their experience? Identify areas of concern and note them for quick resolution. The key question the engineer or manager should ask at this time is, "Can my system requirements be accomplished with equipment and techniques that are already proven in actual field use?"

Is it really necessary to invent something new to get the job done? Are special load transfer mechanisms really necessary? Just because your company is trying to standardize on a type or make of computer, is it really necessary to impose this on the AGVS companies that use a different make as their standard? Are you willing to risk the software rewrite effort even if the vendor says they can do it?

Risk assessment is built in at the concepting stage. Key decisions are made that affect the risk level for the remainder of the project and the life of the system. One of the best ways to develop a feel for the level of risk is to discuss the application requirements with multiple vendors, particularly those with experience in your type of application. Develop a rapport with the people with whom you are comfortable. Respect opinions that may not be what you want to hear. Combine this input with feedback from other users and a realistic assessment of your own plant’s environment. This will help you decide on an appropriate level of risk.

A more conservative approach at this stage can mean a smoother project to implement, and a more reliable system to operate in the long run.