Since the last Forkliftaction.com News
report on AGVs in 2009, some interesting developments have taken place. Melissa Barnett
reports on some of these advances, particularly in the area of hybrid vehicles.
Automated guided vehicles (AGVs) have always been a somewhat contentious piece of equipment in the world of materials handling. Many, including traditional forklift manufacturers and operators, see them as a threat to traditional forklift use. Those in manufacturing can see their potential in cutting costs and improving efficiencies but think them overly complicated and prohibitively expensive except in large-scale use, while those in distribution see them as unable to meet rapidly changing warehouse needs.
Many of these issues are being addressed not only by AGV OEMs but also forklift OEMs, a number of which have joined forces to create new hybrid machines better suited to the needs and demands of today's end-users.
AGV- A definition
AGVs can be defined as "computer-controlled mobile robots used to move materials around a facility", explains Mark Longacre, marketing manager for US AGV technology company JBT Group. "Essentially, this definition hasn't changed in 10 years," he adds.
Linde equipment fitted with Seegrid technology
An AGV can be moved by a number of means depending on its working environment. In the past, magnetic strips and imbedded wires controlled the AGV's route. These days, laser navigation is the preferred system and can be used in conjunction with magnetic strips or spots, particularly in confined warehouse spaces.
German AGV specialist E&K Automation recently designed a system employing seven counterbalance machines guided by E&K's NAV830 laser triangulation system. The system is capable of designing complex AGV routes very simply on a CAD workstation. Laser navigation reflectors are fixed to points around the warehouse, while simulation tools help to optimise the routes and select the required number of vehicles for the job.
Another option, vision navigation, uses a live video stream in real time from cameras mounted in strategic places around the warehouse. It can be interfaced with on-board or remote computers to provide real-time control and vehicle management. Visual guidance systems appear to be increasingly popular with hybrid machine designers.
US automation company Seegrid has been using similar visual navigation technology for some time and believes that the vehicle it has designed using this technology goes beyond the current description of an AGV. Seegrid believes it has developed a third class of vehicle: the robotic industrial truck. The industrial mobile robotics (IMR) technology used in Seegrid's robotic industrial truck employs artificial intelligence, Bayesian statistics, image processing and machine learning methods to enable the vehicle to automate core materials handling processes. Seegrid is currently working on expanding this technology to create a vehicle which it believes will eventually "think" and problem solve on its own.
The type of AGV employed will depend entirely on need. Almost all conventional AGVs share a common platform which is then customised for their specific work environment. In a manufacturing space, the most common AGVs are tuggers and carts equipped with crate and trailers or specifically designed carts to carry assembly parts or stock to a designated place. In a warehouse or distribution centre, automated pallet-handlers or stock pickers are common and will utilise similar attachments to a very narrow aisle (VNA), counterbalance or reach stacker forklift.
Issues and solutions
John Gardiner, general plant manager for Yale Materials Handling Corp US assembly operations, believes that AGVs work well when the material flow layout is well defined. However, he stresses that contrary to some perceptions, AGVs can also be highly flexible if the technology to expand the system is built in during the early planning stages. Peter Holdcroft, managing director of E&K Automation UK, notes that the latest AGV systems are "very flexible, making them future-proof, enabling extensive modification, upgrading and extension as circumstances dictate. The control systems and peripheral equipment are modular and with laser navigation changes to the layout, are particularly straightforward".
Rocla's ATX at work
With new technology available, AGV systems can be implemented without disruption to production and can be designed to complement a pre-existing warehouse management system (WMS). There is a growing trend to combine the two materials handling systems (conventional forklifts and AGVs) on the warehouse floor to maximise flexibility and cost-effectiveness. The success of this option depends largely on the capability and experience of the integrator - the person responsible for the planning and integration of motion systems.
Hesham Mahmoud of US-based Strategic PM Solutions says that "up to 80% of businesses in the US experience defective or inferior automation implementation". He believes this is because process solutions and an objective materials handling operational strategy are not carefully analysed before choosing an AGV vendor. It is suggested that when designing a system, it is important to factor in elements such as shift patterns, labour requirements and average peak demands to the process.
The initial expense of implementing an AGV system has been of main concern to many would-be investors, but cheaper technology and production costs have over the past few years lowered the price of AGVs. And, as Holdcroft points out, " an AGV system, with longer working hours and improved efficiencies, allows western manufacturers and distributors to compete with low-wage countries." However, Stefan Engardt, sales director for Finnish company Rocla Oy, warns that although AGVs have many advantages over conventional forklifts in sustaining quality and quantity of work, they do not necessarily perform well during high-peak material flows. This is because they actually move slower than a conventional forklift.
Another concern with AGVs was their small energy capacity, requiring them to frequently stop and recharge batteries. However, Yoko Ono, from Nissan Forklift Co., says that advances in lithium battery technology and capacitors have addressed this problem. Automatic recharging technology and designated charging stations are now common in recently constructed AGV environments.
Mahmoud believes that the overwhelming advantage of AGVs over forklifts is their safety - for employees, the product and the facility. All workplaces using AGVs report a decrease in the number of back injuries and collisions. This is because AGVs remove from the equation human tiredness, distraction and poor decision-making. AGVs can be fitted with any number of safety devices including obstacle-detecting photoelectric and laser sensors, cameras and automatic variable lift control. EU safety standard EN 1525 directs that all driverless vehicles operating in a mixed environment be fitted with anti-collision and stopping-sensing devices, bumpers and warning lights.
Hybrid - what is it?
In early 2009, E&K Automation and Leibniz Universität in Hannover released a paper outlining their partnership in developing a "people following automated guided order picker". The project aimed to investigate the benefits of automation. Given the recent spate of partnerships between forklift OEMs and AGV OEMs, it seems that the original project has not only been seen to have commercial value but research and development of the concept is being actively encouraged.
New Zealand company INRO specialises in laser guidance technology
A hybrid or dual-use forklift (DUF) is a semi-automated conventional forklift combining the capabilities of a forklift as well those of an AGV. The system combines in one machine the intelligence and flexibility of a person with the reliability and efficiency of an AGV. The equipment can be used with or without an operator, depending on requirements.
Belgian automation specialist Egemin and Mitsubishi Caterpillar Forklift America Inc. (MCFA) have combined expertise to launch the E'gv, a hybrid pallet-handling vehicle which uses the ignition key to either employ the vehicle as a fully automated AGV or manually, depending on which way the ignition key is turned.
In March, German automation company Dematic partnered with US-based Crown Equipment Corporation to collaborate on the research and development of hybrid vehicles. Their first product, the LaserTruck, is an integrated solution that combines Dematic's picking and voice AGV software technology with a Crown PC 4500 series pallet truck.
Both Linde and USA materials handling company Raymond Corporation have agreements with Seegrid to develop hybrid vehicles for the European and North American markets, respectively. The Linde/Seegrid prototype is an automated tow tractor - the P50C, which will be followed by further automated truck types. Raymond plans to launch its vehicle in 2012.
Retro-fitting of automated guidance technology has also been developed as a viable option for hybrid vehicles. New Zealand company INRO uses laser and sensor technology to automate conventional electric warehouse forklifts, heavy-lift LPG and diesel forklifts. It believes that the combination of AGV technology and forklift speed and endurance means better asset utilisation and lower risk for customers wishing to automate.
Slovenian grocery chain Engrotuš d.d uses automated forklifts in its distribution centre for fresh and chilled products. The forklifts are automated with Pick-n-Go technology form German motion specialist Kollmorgen. The technology can be fitted to an existing fleet of forklifts or at the factory. In the Engrotuš distribution centre, the NDC8-equipped forklifts are used to fetch empty roller cages, escort the RFID-controlled pickers to the pick location and to dispatch full roller cages.
Mahmoud believes dual-use/hybrid vehicles are a good way to introduce automation to traditional forklift users. "DUFs give flexibility to some companies, but are not threatening business from the AGV industry" he says. "DUFs are not an AGV replacement, but good for where human interface is already present and may continue. DUFs could be a gateway to AGVs," he adds.
With hybrid vehicles, the customer appears to get the best from both industries: AGV designers provide the navigation technology and automation software while the forklift manufacturers bring the quality and economies of scale that come from mass production, as well as established dealer networks that can service the mechanical systems of forklifts.
Hybrid AGVs are attracting a lot of interest in many sectors of industry, although not all. Pekka Joensuu, systems manager at Finnish AGV manufacturer, Solving Oy, is not convinced that all customers are ready just yet. Despite his reservations, Joensuu believes that within the next 10 years, automated forklifts will account for 10-20% of a company's forklift fleet. Consultant Mahmoud is even more optimistic and believes that up to 80% of new manufacturing and distribution centres will be using some type of automation within a decade.