AGV (Automated Guided Vehicles), also known as unmanned transport vehicles, automated guided vehicles, or laser-guided vehicles, are transport vehicles equipped with electromagnetic or optical automatic navigation devices. They are capable of traveling along a prescribed navigation path and possess safety protection and various transfer functions.
In industrial applications, automated guided vehicles (AGVs) do not require drivers and are powered by rechargeable batteries. Their movement and behavior are typically controlled by a computer, or by using an electromagnetic path-following system. These electromagnetic tracks are attached to the floor, and the AGV moves and operates based on the signals transmitted through them.
Features of AGV
A key feature of AGVs is their unmanned operation. Equipped with an automated guidance system, AGVs can automatically travel along predetermined routes without manual guidance, transporting goods or materials from the starting point to the destination. Another characteristic of AGVs is their flexibility, high degree of automation, and high level of intelligence. AGV travel paths can be flexibly changed according to warehouse storage requirements and production processes, and the cost of changing operating paths is significantly lower compared to traditional conveyor belts and rigid conveyor lines. AGVs are generally equipped with loading and unloading mechanisms, allowing them to interface automatically with other logistics equipment to automate the entire process of loading, unloading, and handling goods and materials. Furthermore, AGVs offer clean production advantages. Powered by their own batteries, they operate without noise or pollution, making them suitable for many environments requiring a clean working environment.
AGV Classification
1. Electromagnetic induction guided AGV
Electromagnetic induction guidance typically involves burying wires along a pre-defined travel path on the ground. When a high-frequency current flows through the wires, an electromagnetic field is generated around them. Two electromagnetic sensors are symmetrically installed on the left and right sides of the AGV. The difference in the intensity of the electromagnetic signals received by these sensors reflects the degree to which the AGV deviates from the path. The AGV's automatic control system uses this deviation to control the vehicle's steering. Continuous dynamic closed-loop control ensures that the AGV stably and automatically tracks the set path. This electromagnetic induction guidance navigation method is used in the vast majority of commercially available AGVs, especially suitable for medium and large-sized AGVs.
2. Laser-guided AGV
This type of AGV is equipped with a rotatable laser scanner and laser positioning marks with highly reflective reflective plates installed on the walls or pillars along the running path. The AGV relies on the laser scanner to emit laser beams and then receive the laser beams reflected back from the surrounding positioning marks. The onboard computer calculates the vehicle's current position and direction of movement, and corrects its orientation by comparing it with the built-in digital map, thereby achieving automated material handling.
The application of this type of AGV is becoming increasingly widespread. Furthermore, based on the same guidance principle, if the laser scanner is replaced with an infrared transmitter or an ultrasonic transmitter, the laser-guided AGV can be transformed into an infrared-guided AGV or an ultrasonic-guided AGV.
3. Vision-guided AGV
Vision-guided AGVs are a rapidly developing and maturing type of AGV. These AGVs are equipped with CCD cameras and sensors, and their onboard computer stores a database of images of the surrounding environment along the AGV's intended path. During operation, the cameras dynamically acquire images of the vehicle's surroundings and compare them with the image database to determine the current position and make decisions about the next step.
Because this type of AGV does not require any human-defined physical path, it theoretically has the best guiding flexibility. With the rapid development of computer image acquisition, storage, and processing technologies, the practicality of this type of AGV is becoming increasingly stronger.
In addition, there are various other types of AGVs, such as ferromagnetic gyroscope inertial guided AGVs and optically guided AGVs.
AMR is an upgraded version of AGV.
AMR (Autonomous Mobile Robot) is a type of robot that uses software to map the interior of a factory or import pre-installed factory building plans for navigation. This function is analogous to a car equipped with GPS and a pre-installed map. Once the car is set with people's residences and work addresses, it can generate the most convenient route based on the map's location.
Similar to AGVs, AMRs are essentially an upgraded version of AGVs, but they do not require external infrastructure such as magnetic strips, guide rails, or QR codes. AMRs can be further divided into two categories: one based on robot swarm management, and the other based on order picking optimization.
The difference between AGV and AMR
Both AGVs and AMRs can transport materials, but their similarities end there. The difference between AMRs and AGVs is that the former has powerful computing capabilities and can perceive the surrounding environment through sensors and make corresponding decisions; while the latter is just a large actuator, and its every move depends on the scheduling of the central control system.
① Differences in path planning
AGVs cannot handle complex, cumbersome, and intelligent commands, are prone to interruptions during equipment updates, and must stop operating if they encounter obstacles during transport. AMRs, on the other hand, are more sensitive, can intelligently select the most efficient route to the destination, easily bypass obstacles, automatically transport goods across layers, complete tasks efficiently and safely, and optimize productivity.
② Differences in application scenarios
In this application, AGVs are relatively simple, limited to following a fixed route installed on the ground within the factory. Changing the route requires replanning and re-layouting the ground, causing production interruptions and other economic impacts. AMRs, on the other hand, only require simple software adjustments to change tasks, and can meet the needs of constantly changing environments, production requirements, and task priority settings.
③ Differences in environmental requirements
Warehouses in China generally have poor infrastructure, with severe ground subsidence, uneven surfaces, and even cracks. AGVs cannot adapt to this environment, but AMRs can. Their ready-to-use feature allows companies to fully control the robots and their functions.
④ Differences in input costs
More powerful features mean a higher unit price, but AMRs do not require factory modifications, resulting in better overall cost control.
