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LGV Vehicle: What is a Laser Guided Vehicle?

Laser Guided Vehicles (LGV Vehicles) are fast, accurate and reliable. This navigation technology is traditionally used in automated forklifts that are boosting warehouse efficiency all around the world.

What are Laser Guided Vehicles? Advantages and Disadvantages

 Forklift agv with laser navigation

 

Table of Contents

What is a Laser Guided Vehicle?

What is the difference between AGV and LGV?

What Types of AGV perform Laser Guided Navigation?

How does a Laser Guided AGV work?

What are some advantages to LGVs?

What are some disadvantages of laser navigation?

When is it useful to choose a Vehicle with Laser-Guided Navigation?

  

What is a Laser Guided Vehicle?

A LGV Vehicle is an AGV that navigates with a laser positioning system.  Check this video to have a better understanding. 

 

What is a Laser Guided Vehicle?

Do you like this picture... it's an extract from the LGV Infograph. Registered members can download it here: DOWNLOAD THE INFOGRAPH

What is the difference between AGV and LGV Robot?

A LGV Robot is just an AGV performing laser triangulation for its agv guidance technology. Thus, LGV refers to a navigation methology and not to a specific type of AGV. In fact we could have automated forklifts or tow tractors under the LGV umbrella.

For this reason, there is no specific difference between AGVs and LGVs: LGVs are just AGVs with Laser Navigation Triangulation. 

 

What Types of AGV perform Laser Guided Navigation?

Thanks to its reliability, laser navigation is widely used in Automatic Forklift trucks working in warehouses and performing stocking applications where is necessary to have an accurate positioning tolerance. 

Laser Navigation Technology can also be used in Tow Tractors AGVs.

Mobile Robots performing Laser Navigation are classifieds as AGVs and not as Autonomous Mobile Robots (💡 Check this article for more details: What is the difference between an AGV and an AMR?)

It's important to understand that LGVs are step by step being substituted by more modern navigation systems using Natural Navigation (so by AMRs). These vehicles, use the environment to navigate and, if required, use Laser Triangulation to obtain a more accurate positioning. 

How does a LGV Vehicle work? 

LGV Vehicles are equipped with a 2-dimensional AGV LiDAR Navigation Sensor  (simply called a Navigation Device or Laser Emitter).

LGV with Navigation Laser

The navigation Laser emits a continuous beam of modulated laser light in a 360 degree pattern.

The laser beam interacts with reflectors (also called "targets") positioned in the AGV working area. Depending on the Laser device manufacturer, LGVs calculate and correct their positioning between 30 and 40 times per second. These sensors are incredibly accurate. 

Once the laser "impacts" the reflector, the beam is sent back to the navigation laser that calculates the laser go&back time together with radial coordinates. These data allow to calculate the X,Y coordinates of the reflectors and the AGV.

The centre of the reflectors must be positioned at the same height of the Navigation Device, and typically, at a maximum of 100 ft (30 meters) far from the AGV.

     

What are the types of reflectors used in Laser Navigation?

  

There are two main types reflector design used in laser navigation, Flat Reflectors and  Cylindrical Reflectors.

        

Flat Reflectors are simple and inexpensive strips of retro-reflective tape. They are easily fitted with a contact adhesive side. Flat reflectors offer great accuracy.

Cylindrical Reflectors. Cylindrical reflectors are more difficult to deploy because it is necessary to calculate a fixed centre point for the reflector. They are more difficult to fix, more vulnerable and intrusive in the user’s facility.

How does the Laser-Guided AGV System know where the vehicle is?  

  

The AGV must receive the feedback arriving from at least three reflectors.

First, it is necessary to measure the reflector position. The AGV will use the reflector position as a reference for its navigation.

The reflectors are “seen” by the navigation device and their position information is adjusted, rotated, and edited by a specific software, so that the information of the reflector is consistent with the layout of the workshop. 

In other words, the AGV matches the “observed” position of the reflector with a “theoretical” position on a 2d cad drawing.  

Once the AGV has positioned the reflector, the laser scanner obtains its distance from each of the three reflectors, calculating the current coordinate position of the laser scanner by the triangulation method.

How do Laser Guided Vehicles work?

 

This calculation is made by complex algorithms and must take into consideration other variables such the vehicle speed, etc.

Moreover, it is mandatory to have continuously-updated, accurate information about the vehicle’s position and heading to minimize calculation errors.  

These errors could increase in the future because of several factors like the environmental conditions, encoders wear, damaged reflectors. 

    

Advantages of Laser Guided Vehicles

   

What are some advantages to LGVs?

   

Seamless. There is nothing laying such inductive wire, magnet. LGVs do not affect the neatness of the site.   

LGV installation is relatively fast. A big part of the job is done in an office by the supplier's engineers.

No invasive installationLGVs only require placing reflectors around the facility. 

Accurate positioning. Positioning algorithms are very sophisticated allowing position accuracy close to ± 2 mm

Laser navigation allows high speed vehicles that can achieve up to 2 m/sec (6,5 ft/sec).

No costs due installation maintenanceYou only have to keep reflectors clean.

  

What are some disadvantages of laser navigation?

 

Disadvantages of Laser guided vehicles

  

Once installed, LGV 's tracks can be modified only by skilled engineers. If you wish to update a path you have to call your supplier.

LGV vehicles use to be expensive. Laser navigation required sophisticated devices and algorithms that are typically expensive. 

Harsh environmental requirements, needing specific conditions: light, floor, etc, .

 

When is it useful to choose a Vehicle with Laser-Guided Navigation?   

Quick conclusion: When you need speed, accuracy and you have multiple destinations and tracks.

The main advantage compared with other navigation methods is its accuracy. LGVs are extremely accurate, thus they are the best solution for racks management in warehousing. In fact, AGV VNA or Reach Truck AGVs are Laser Guided Vehicles. 

         

💡 Just consider what kind of accuracy is needed to place 2.000 lbs (near 1 ton) on a rack  25 ft (near 10 m) high....   

 

Do not miss the article Warehouse Robots Applications if you wish to learn more about LGVs and other robots working in warehouses.

When to choose a LGV

 

Laser-Guided Navigation is easy to install. AGV supplier will install all the reflectors and simulate the AGV path on the AGV Management System to define your needed AGV routes.

Everything is “virtual” and there are no fixed infrastructures such tapes on the floor or wire beneath the surface. In the same corridor, you can have as many virtual routes as you wish.

So, if your project requires a very big and complex route system, it would be efficient and effective to have Laser-Navigation Vehicles.

    

Related articles in AGV Network

What is an Automated Forklift? -  Types and manufacturers. 

Warehouse bots - All the types of robots and their applications in warehouses  

Automated Pallet Mover The quickest material handling automation robot 

Automated Very Narrow Aisle Trucks  - List of Manufacturers and Characteristics of Very Narrow Aisle Robots

 

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Category: AGV TECHNOLOGY