For decades, batter-powered Automated Guided Vehicles (AGVs) have been a mainstay in assembly lines and material-handling centers because they are well suited for transporting small, light loads on varying paths. The cost of this approach is not insignificant, as it requires a stock of spare batteries and a stable of powered-up AGVs to be at the ready. In addition, more and more US companies are taking costly steps to address the environmental impact of the disposal of lead in batteries. In spite of this, battery-powered AGVs remain a frequently chosen option for transporting light loads.
But when it comes to handling heavy loads, the battery-powered AGV is not up to the task. Its short battery life limits it to light loads of limited duration. The need for AGVs is just as great for heavy materials, but a different design is required.
Now, vehicle manufacturers, aerospace companies, and material handlers with heavy products can choose inductive power transfer (IPT) based battery-free AGVs. Off-road vehicle manufacturers, automakers, and aircraft manufacturers are working to design systems to carry tens of thousands of pounds. Well-established in Europe, battery-free AGVs are relatively new to the US. Hereís a time-lapse video of one of these AGV lines in action.
Superior Controls recently helped a construction vehicle manufacturer move production to the US from Japan. That decision was based on three primary benefits:
- Minimal time for installation and future line changes
- Integrated software and controls with asynchronous line indexing
- Safer work environment with less maintenance
Traditional chain-based conveyance requires a major capital investment thatís physically attached to the building. For example, an overhead power and free conveyor for a vehicle manufacturer requires thousands of pounds of steel, and in-floor conveyance requires deep pits and complicated mechanical assemblies to pull the product along the line.
Alternatively, IPT-based conveyance lines are created by carving out two shallow floor channels to contain power and communications cables which are then epoxied over to create a flat floor. Rather than relying on mechanical parts to guide the system, battery-free AGVs rely on integrated software and controls. This makes for a faster installation and change process, since the floor changes are simple and the software and controls are changed independently. There are no pits to be dug, no structural steel to be hung.
The factory creates multiple vehicle types on a single line, and task completion time can vary greatly. A traditional conveyance system moves only as fast as the slowest task. Integrated software and controls for asynchronous indexing solves this problem. Since thereís no chain tying one product to the next, each one moves forward when a process is complete. Potential bottlenecks are anticipated and paths can branch off and rejoin at any point. Since battery-free AGVs can power up in the station and/or in transit, thereís no loss of power by waiting for the next station or changing paths.
One particular customer wanted a safer working environment with lower maintenance costs. With traditional conveyance, there are worker risks, such as trip hazards and collisions. Today, operators perform all of their work on a clean, smooth, flat floor that is free of obstructions, trenches, or floor-mounted rails. In addition, the battery-free AGVs have sensors so that they stop when something crosses their paths. Approachable from 360 degrees, access to a vehicle is safe and ergonomic, and does not require the operators to avoid any conveyance moving overhead or below.