What Are Autonomous Robots? | An Easy-to-Understand Webinar

What is an AGV (Automated Guided Vehicle)?

Hama-chan: Professor Hashimoto! The other day, I spotted an AGV hard at work in the factory! I heard that they can transport a wide variety of goods in large quantities within the warehouse all on their own!

Professor Hashimoto: That’s right. They’re called AGVs (Automated Guided Vehicles). Using guidance systems like magnetic tape, these vehicles can transport necessary parts to the right places without getting in the way of workers—essentially doing the job for them. In addition to operating in factories and warehouses, they’re also used for delivery, security, and cleaning in smart buildings.

Guidance method		Features	Image
First Generation	Electromagnetic Induction	A weak alternating current is passed through metal wires embedded in the floor; the system moves by detecting the resulting magnetic field with sensors
	Magnetic Induction	Magnetic rods or magnetic tape are installed on the floor, and the system guides the robot by reading them with magnetic sensors. While this is the most widely used system in Japan, it is expected that there will be a shift toward second- and fourth-generation systems, or that hybrid types will become more prevalent.
Second Generation	Image Recognition	The system reads symbols such as QR codes or AR markers drawn on the floor or ceiling to determine its own position. This enables high-precision positioning.
Third Generation	Laser (Reflectors)	Reflectors are mounted on walls and pillars inside the building; the vehicle estimates its position based on laser reflections and navigates autonomously. A sufficient number of reflectors must be installed throughout the vehicle’s entire operating area.
4th Generation	SLAM (Simultaneous Localization and Mapping) / Visual SLAM / LiDAR SLAM	These robots navigate by estimating their position using sensors such as cameras and lasers, along with encoders and gyroscopes. Autonomous navigation is possible without the need for guide rails. They are often referred to as Autonomous Mobile Robots (AMR), Non-Guide AGVs, or Next-Generation AGVs.

・While "AGV" is the globally accepted term, the autonomous type is increasingly referred to as "AMR" to distinguish it.
 

Professor Hashimoto: AGVs (automated guided vehicles) have been in use for some time and are capable of precise autonomous navigation. However, they were unable to determine their own routes or navigate around obstacles.
  

What is an AMR (Autonomous Mobile Robot)?<

Hama-chan: Aren’t there any robots that can determine their own routes and navigate on their own?

Professor Hashimoto: Robots capable of autonomous navigation are called AMRs (Autonomous Mobile Robots). They are sometimes referred to as non-guided AGVs or next-generation AGVs.
 

Hamachan: With the advent of autonomous mobile robots (AMRs), we can now automatically collect and transport products and parts!

Hama-chan: So they can transport the same products and parts! In that case, what’s the difference between AMRs (autonomous mobile robots) and AGVs (automated guided vehicles)?

Professor Hashimoto: While AGVs (Automated Guided Vehicles) function like trains running on fixed tracks, AMRs (Autonomous Mobile Robots) are more like cars that can work alongside people. If you look at the guidance systems, there are differences as shown in the diagram. I hear hybrid models are starting to appear these days, too. Also, AMRs (Autonomous Mobile Robots) are sometimes used in combination with collaborative robots!

The Difference Between AMRs
and AGVs 

Hama-chan: So the collaborative robots we learned about last time are being put to good use here too!

*For more details, click here ▶ What Are Collaborative Robots? Introducing Mechanisms That Ensure Safety for Robots, Machinery, and People

Hamachan: Could you explain the key components of AMRs (autonomous mobile robots) and AGVs (automated guided vehicles)?

Laser SLAM technology for obstacle detection

Professor Hashimoto: Fourth-generation AMRs (Autonomous Mobile Robots) generally use the SLAM method. They use cameras and laser sensors to observe their surroundings and, in combination with encoders and gyroscopes, can estimate their own position. Products that utilize SLAM technology include the latest model of cleaning robots, drone-based autonomous delivery, and Mars rovers.

Hamachan: So SLAM technology is actually being used in everyday settings, isn't it!
 

Visual SLAM and LiDAR SLAM

Professor Hashimoto: There are two types of SLAM: Visual SLAM, which is based on image processing using camera images, and LiDAR SLAM, which is based on point cloud data measured by LiDAR.

Professor Hashimoto: LiDAR is used in self-driving cars, drones, and the iPad Pro released in March 2020. There are even apps now that let you scan 3D spaces and easily create augmented reality (AR) models.

Hamachan: I recently used an augmented reality (AR) app that lets you virtually place furniture in your room! The technology is really advancing!

Emergency Stop Function

Professor Hashimoto: Recent AMRs (autonomous mobile robots) and AGVs (automated guided vehicles) are being developed in sizes ranging from small to large. For large products and parts, they can even transport items weighing over one ton.

Hama-chan: That’s amazing! It seems like the functions required in emergencies will continue to increase.

Professor Hashimoto: Exactly. That’s where non-excitation brakes come into play. Brakes designed for emergency stops on AMRs and AGVs that operate day and night have to meet a wide range of requirements.

Mr. Hashimoto: The structure of the drive wheel for an AGV with an integrated motor looks like the one in the photo. The component located roughly in the center is a self-energizing brake. If the motor isn’t integrated, I recommend using a coupling to connect it to the motor. This makes removal easy and improves work efficiency during maintenance.
  

Hamachan: So, for AMRs (autonomous mobile robots) and AGVs (automated guided vehicles) to operate safely, the presence of non-energized brakes and couplings is crucial, isn't it?