AGV’s or AMR robots, or what level of autonomy to use?
Automation of intralogistics processes is gaining popularity. Manufacturers compete in promoting the advantages of their vehicles and autonomous robots such as AGV (Automated Guided Vehicle) and AMR (Autonomous Mobile Robot), mainly praising the advantages of the latter. Many people wonder what exactly are the differences between the two types of transport. At first glance, the differences in the way of navigation are the most visible. Indeed, AGV’s run on magnetic or optical tapes. Such vehicles are often called line followers, while AMR robots use more sophisticated navigation methods, e.g. using SLAM (Simultaneous Localization and Mapping) technology. But is that the most important difference? And do AMR’s have to run without tapes at all?
At first glance, AGV and AMR look very similar. They have an almost identical mechanical structure, drive system and safety solutions. The only difference, often imperceptible, is the number of additional sensors, such as 3D cameras and high-performance control computers. So if, in terms of the hardware, both vehicles are constructed similarly, where are these fundamental differences?
The level of autonomy decides
AMR are robots with high autonomy. Thanks to it, they are able to operate in a changing industrial environment, e.g. about avoiding travel by delineating a path. On the other hand, the AGV no longer has full autonomy and the logistic tasks are up-to-date in advance on not previously defined work paths. Was it a systemic disadvantage of AGV intralogistics services? Not necessarily, it all depends on the working environment of the intralogistics system. Since the limit of autonomy at which AGV ceases to be AGV and becomes AMR has not been clearly established, analogies can be found in the world of similar technologies.
For example, to the scale developed in 2014 in the US by SAE (International Society of Automotive Engineers) for consumer vehicles such as cars. In this model, the level of autonomy is defined from 0 – 5, where 0 is full control of the vehicle by the driver and 5 is a vehicle where driver intervention is not needed. Transferring these assumptions to the world of intralogistics automation, we can say that 0 would be an operator-operated forklift, 1,2,3 are AGV’s and 4 and 5 are AMR robots. However, it is important to note that whether you drive a car that is more or less equipped with advanced driver assistance systems, the goal is to reach the destination point. This will not always be accomplished faster with a fully autonomous vehicle. AGV’s/AMR’s can therefore have different levels of autonomy. So what makes a mode of transportation more or less autonomous?
Now that we have established that AGV’s and AMR’s are almost identical in terms of hardware, autonomy is determined by the advanced control algorithms implemented in the computers controlling the robots, which are most often used for such functions as obstacle avoidance, navigation path mapping, identification of logistic carriers, advanced energy balance management, diagnostic functions (predictive maintenance), or speed adjustment to prevailing conditions. Thus, it is the quality of the software that is crucial to whether an autonomous vehicle is still an AGV or already an AMR. The type of navigation to be used by the robot is only one of many parameters that the architect of the intralogistics system takes into account when preparing a tailor-made solution. Of course, the use of SLAM technology gives the possibility to increase the level of autonomy of the vehicle, but it is not the only and often not the most important element determining whether the vehicle is still AGV or already AMR.
AGV/AMR is just a tool
From the perspective of the intralogistics system architect, it is above all the goals and tasks that are to be achieved by the system in accordance with the process requirements, e.g. system performance, that count. The point is that the system should have exactly those functions, implemented by means of hardware and software, which are needed in the factory for optimal operation of the production process. Obviously, taking into account physical limitations often resulting from the infrastructure, process limitations resulting from production technology and financial limitations, which often determine the decision to invest in automation.
Sometimes it may turn out that many of the functions typical of AMR robots are unnecessary for a given process and an AGV-based system is sufficient. This also has a bearing on the, very important, cost of implementation. As a rule, the more complex the software, the higher the price of the system. As an interesting fact, the company Etisoft Smart Solutions in one of the implementations, applied AMR robots using magnetic tape navigation. So it is not said that this type of robots must use only SLAM navigation. Moreover, in some factories there are even contraindications to using AMR with this type of navigation. Reasons for this can include heavy dust in the plant that prevents sensors (such as lidars or 3D cameras) from working properly, or poor quality WiFi network infrastructure that the robot uses to transmit telemetry data. There are also reverse situations, e.g., a system based on simpler AGV’s is sufficient to operate the process, but the conditions in the factory (e.g., other heavy vehicles that can destroy the magnetic tape) make it necessary to equip it with SLAM-type technology or another type of navigation.
The best place to start is by consulting with experts
Designing an intralogistics system is a challenging project that requires design and implementation competence. You should start by talking to experts who have completed projects in manufacturing companies and can design a “tailor-made” system. They will advise on what software should be equipped with the robot, depending on the purpose to be achieved. So whether it will be an AGV or an AMR is a secondary question, although it is to be expected that the future will rather be dominated by vehicles with a higher degree of autonomy.
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