M AT E R I A L H A N D L I N G , E A R T H M O V I N G , M I N I N G & L O G I S T I C S E Q U I P M E N T S

39Oct/Nov-12

vast majority being found throughout construction, manufacturing, logistics, and service. Companies are expecting material handling solutions to be flexible with abilities to easily adjust as the facility/operation adjusts. Using the facility infrastructure as a means for location identification, vision navigation makes the fixed target way of navigating obsolete. Vision navigation solution provides customers the ability to quickly adjust material handling solutions to meet the ever changing demands. No longer is the automation supplier needed to make the required adjustments. Vision system robots provide the lowest cost of ownership compared to competing fixed navigation solutions.

Distribution environments are less structured and require more employees to operate. Companies turn to stereo vision to automate non-value-added movement because stereo vision is flexible.

Stereo vision-guided robotic trucks transport finished goods from the end of the line to the warehouse, wrapper, and shipping dock. Robotic trucks automatically transfer product to the appropriate destination and then return to the line for more work.

Stereo Vision-Guided for Navigation

Daimler Trucks North America, North America's leading manufacturer of commercial industrial vehicles, was seeking to institute a system-wide continuous process improvement initiative, with the stated goals of streamlining parts inventory management, reducing excessive labor and improving fulfillment processes. Moravec's Seegrid team offered Daimler multiple shift and route flexibility which were easy to change as shifts and needs arose. This was accomplished without facility modifications, allowing Daimler to avoid costly tape, wire guides and other expensive, unfamiliar AGV (automated guided vehicle) technology.

This stereo vision-guided robotic solution was easy to use and train, required less maintenance, and presented a lower Total Cost of Ownership than similar platforms with existing equipment.

Stereo Vision Applications in Other Industries and Applications

Moravec believes companies will leverage success in the materials handling industry into additional addressable markets. “This solution has the potential to solve problems in other markets that face similar problems, including: indoor/outdoor industrial vehicles—vehicles that operate in shipping ports, corporate campuses, and military bases—and dedicated outdoor vehicles for agriculture, military, and forestry,” suggested Moravec.

Disadvantages of Vision-Guided Alternatives: Floor Bases & Non-Floor Based

The most widely accepted groupings for vision-guided alternatives are floor based and non-floor based.

Floor Based Solutions

The hallmark of floor based systems is that the floor typically never changes therefore it is a source of constant feedback; this characteristic does not apply to tape, as it is pulled up easily.

Wire solutions have great limits on capabilities. Once installed it is difficult to change as the floor needs to be recut and new wire placed in the grooves. It is also very expensive to install at roughly $20 per foot.

Few companies provide professional floor cutting, and few applications still use wire guidance (the exception being Very Narrow Aisle systems), so it is a scheduling issue often taking more than a month.

The most typical applications are VNA and these are typically 300 foot aisles with roughly 10 aisles. This typically takes two days to cut and one day to install the wire and grout. Significant productively losses are incurred, since no facility operations (where the floor is being cut) are permitted due to the cutting equipment and in some cases the dust produced by the cutting.

There are feature benefits to wire in certain instances; the data driven results can include savings of money, time, safety, mobility, training, cultural adaptation. Wire guidance is a stable guidance method as the floor does not change and the wire is protected in the grooves. When a breakage in the wire does occur (typically at expansion joints where the floor moves) it is very difficult to find the breakage and requires specialized equipment. When a breakage occurs, the entire path using that frequency is down and AGVs cannot navigate. More productivity is lost.

Tape solutions also have great limits on capabilities since it is very susceptible to damage due to industrial equipment (however it is fairly easy to change the path due to the tape being placed on the floor surface). It is quick to install, as the tape is typically stocked by the vendor. Installation time is fairly quick since it is placed on the floor surface. Much like wire facility work, the area needs to be cleared for the workers to lay the tape.

The benefits of tape are the speed at which it can be installed and the speed at which it can be modified as a floor based system. The reference point (the floor) rarely changes but the tape is very susceptible to damage. It is easy to repair by placing new tape on the damaged area.

Magnet solutions have significant limits as well. Once installed, it is difficult to change, but not nearly as difficult as wire since magnets are placed every 10 to 20 feet apart. The magnets need to be placed in holes that are drilled throughout the facility which also causes a disruption to operations. In some systems the magnets are also surveyed into the guidance system, causing additional disruption and costly loss of productivity.

Typically, magnets can be installed within a month because there are more companies that

can accurately drill and place the magnets. An

entire system is normally installed and surveyed

in two days. Magnets are more flexible than wire

and far less expensive to install. Magnets

typically cost about $10 apiece and the drilling

represents an additional cost calculation.

Non-Floor Based Solutions

Non-Floor based solutions are by far the most

flexible.

Laser has certain limits on capabilities,

specifically LINE OF SIGHT. Due to the

technology the system must see the targets to

navigate so they must remain visible. This is

sometimes a problem due to plant operations.

Laser targets also must remain clean and the

targets usually mounted in a position that is

difficult to reach. Laser guidance, being a non-

floor based system, is highly reliant on the

vehicle calibration and the perfect mounting of

the laser heads on the vehicles. Any

discrepancies across the fleet will make it very

difficult to install a system as the vehicles will all

guide differently. The biggest issue with Laser

guidance is cost. Typical laser targets cost the

end user roughly $100 each and typical vendors

mount a target every 25 feet; this requires a

surveyor to precisely get the X,Y coordinates

and pass these to the vendor.

Laser is the most flexible navigation system

(aside from vision) as there are no floor based

modifications and the guide paths are virtual.

Change is easy, but must be done by the vendor

(even though some vendors claim that users can

make the changes, which has been proven

blatantly false.)

Installation of lasers is less impactful than a

floor- based system, but still has operational

impact as the targets must be mounted and

surveyed.

Stereo Vision-Guided Solutions are the Future

Now

Cur rent s tereo v is ion requi res h igh

manufacturing precision and complex software.

As processing power increases, it will be

possible to develop self-correcting stereo

systems. It will also allow for specialized

processors that reduce the computation costs.

Stereo vision will be more broadly applied to

vision tasks. This will allow for more robust

systems for object identification, tracking, and

navigation. The alternatives are past (and

antiquated) technologies. Leadership requires a

vision, a stereo vision-guided solution.

President Truman concluded, “Men make

history not the other way around. In periods

where there is not leadership, society stands

still. Progress occurs when courageous, skillful

leaders seize the opportunity to change things

for the better.”

M AT E R I A L H A N D L I N G , E A R T H M O V I N G , M I N I N G & L O G I S T I C S E Q U I P M E N T S

38 Oct/Nov-12

Thomas R. CutlerPresident & CEO TR Cutler, Inc.E : trcutler@trcutlerinc.com

Stereo Vision-Guided Technology andAutomation Material Handling Insight

To understand the state of stereo vision-guided

technology today, and where it is going in the

future, it is essential to understand the history.

One of the pioneers in this technology is Dr. Hans

Moravec, interviewed recently noted, “I have

worked in the area of stereoscopic 3D vision for

“The only thing new in the world is the history you do not know.”

President Harry S Truman

offered commercially.”

Commercial Application of Stereo Vision-

Guided Technology

Moravec, founder and chief scientific officer of

Seegrid, developed primary navigation sensors,

selection, feature matching, feature projection,

ranging and communications.

Stereo Vision Applications in the Material

Handling Industry

Materials handling solutions are increasingly

stereo cameras that use global shutter CMOS imagers. Stereo cameras offer a number of benefits including: no moving parts, large sensing envelopes, low power consumption, non-radiating operation (stealth), and fast data capture rates. Stereo cameras also have a drawback: poor data output. This effectively prevents many firms from using CMOS imagers in an automation function. Moravec asserts his company has gained a significant competitive advantage by overcoming this limitation, through its well-developed software stack and set of manufacturing processes. Stereo vision-guided technology now achieves very high performance at low cost. The software stack includes: image capture synchronization, imaging control, image rectification, feature

mapping the environment of mobile robots for over thirty years. The basic idea of using multiple sets of stereoscopic cameras to allow a robot to see three-dimensionally in all directions was occasionally discussed in my circles in the 1980s, but cameras and image digitizers were very expensive at that time, and computer memories and speeds too small to handle so many images effectively.” Moravec added, “Usually the idea was deemed too simple to publicize and too impractical to implement. By the end of the 1990s, however, our computers, had become over one hundred times as power ful, and multi-camera panoramic s t e r e o s c o p i c c a m e r a s a n d r e l a t e d configurations began to be more frequently mentioned, constructed experimentally and

being employed strategically by companies to reduce inventory levels, improve order-to-delivery cycles and help companies adjust to constantly changing consumer demand. Manufacturing, distribution, consumption and disposal are all areas in the product life cycle that rely on material handling equipment. A wide variety of materials handling systems exist today including conventional, human-operated forklifts, carousels, automated storage and retrieval systems, rail and wire vehicle systems and intelligent conveyors. The materials handling industry's systems and operations are highly standardized globally. Materials handling equipment is sold into virtually all discrete process and service industry sectors, with the