The challenges of transferring a variety of materials on a demanding timeline are growing rapidly across all industries. This ever-increasing demand is creating stress in manual material handling situations, which leads to worker fatigue and, eventually, quality and throughput issues.
Technological advancements are finally providing a solution to this problem in the form of autonomous mobile robots (AMRs), which can transport materials throughout dynamic environments on a 24/7 timetable. However, not all AMRs are created equal.
Investing in AMRs can lead to significant gains in productivity and throughput. But before making the investment, it is crucial to consider the payload capacity and process needs of the application. You should also find out about a particular AMR technology’s speed, whether it can work in dynamic environments and around people, and whether there is an effective means of coordinating multiple robots in a fleet.
1. Payload requirements
Payload capacity is one of the most critical considerations when you’re selecting an AMR. Some robots have sturdier frames that are excellent for carrying bulky items and pallet-sized loads. There are other AMRs that are optimized for lighter loads. You must determine the range of items you need to transport, and then select the robot with the appropriate payload capability to address these needs.
Generally, an AMR’s size will increase when its payload limits get higher. A large AMR can be problematic for applications with less space for it to maneuver. In applications that have a variety of items to move, it is often a good idea to have robots of several sizes working together to address both payload and accessibility requirements.
2. Process and throughput requirements
When determining if an AMR’s capabilities meet your throughput requirements, it is critical to consider the nature of the process. Understanding the entire process, and the throughput requirements, helps to “size” the solution capabilities appropriately and predict future process needs as well. It is important to address not only the immediate needs, but also the expansion of operations to avoid running into throughput bottlenecks.
AMR fleets can be expanded by adding more robots. However, when the scale of capabilities is becoming larger, a long-term solution should be implemented. For instance, if you’re expecting to move heavier payloads in the future, it would be better to invest in heavy-duty AMRs now before the need becomes urgent.
In general, a larger work area typically requires more AMRs, but understanding the specific process and throughput requirements is key. If the overall work area is large but the process only needs to move materials in short distances, you can use fewer robots by allocating units to stay in specific areas and reducing overall travel time. If the process requires traveling over large areas and maintaining a reasonable cycle time, then more units are needed.
3. Robot speed and runtime/uptime
Runtime refers to the length of time a robot can run on a single charge. Uptime is the time a robot can operate taking into account the time the robot can operate on a single charge plus the charge time. These key considerations help determine whether an AMR can move the materials for your process, how quickly it can move them, and how many robots will be needed based on your application’s throughput requirements.
For example, if the process contains multiple separate jobs and they need to be assigned to the available AMRs, the runtime of an AMR can be shorter to give it more opportunities to charge. In the same scenario, if the work areas are small, then a smaller number of AMRs can be employed more frequently with greater runtime/uptime and faster speeds.
4. Safety in dynamic environments
According to the Material Handling & Logistics U.S. Roadmap 2.0, the material handling and logistics workforce of 2030 will involve humans working directly with automation technologies. This means safety is an essential consideration for AMRs. You need to choose AMRs with the most advanced environment detection technology, such as lasers and sensors, to ensure the robots can operate safely around people.
Most AMRs are equipped with sensors to detect objects between floor level and the average height of a person’s knee, so they have little trouble detecting shelves set on the ground or people walking around. However, things can get tricky when there are pieces of equipment hanging from the ceiling or drawers sticking out unexpectedly from cabinetry. Depending on the environment – and especially if the AMR is going to be transporting objects of a certain height – it may be necessary to select a robot that includes side lasers to help it avoid hitting any hanging or protruding obstacles.
5. Ability to work collaboratively in a fleet
The noticeable advantage that comes from using a mobile robot often leads to an interest in developing an AMR fleet to cover the entire operation. This means AMRs need to come with a so-called fleet management system that will automatically allocate the work to a number of robots in the most efficient way. Since a good fleet management system coordinates AMRs to share jobs in such a way that the fewest possible robots are allocated to a certain task, it helps you maximize your investment.
There are two main ways to identify a good fleet management system. The first is how well it manages traffic. It should control the traffic in such a way that AMRs avoid blocking each other’s paths or waiting too long for the other to pass. Secondly, the system needs to efficiently manage the jobs. It should allocate the list of jobs in the most productive way so that all tasks are completed in the least amount of time with the least distance travelled overall among all the robots in the fleet. These two features free up your time to focus on the larger picture of task accomplishment rather than spending lots of time commanding individual robots.
A good fleet management system can even “look ahead,” meaning it can predict which nearby robot will be available soon to work on the next job. Furthermore, it is ideal if the system is based on dedicated hardware to eliminate any competition for IT resources within the organization. By having a dedicated piece of hardware that is ideally tweaked for running the software to keep the robot workforce performing, you need not worry about downtime originating from problems related to a shared server.