Maintaining large fleets of autonomous mobile robots (AMRs) is essential for ensuring efficient and reliable operations in industries such as third-party logistics (3PL) and service providers. Despite their autonomy, AMRs require human oversight and regular maintenance to function optimally. Service and maintenance are major drivers of the total cost of ownership and define ROI.

Daily Operations and Reactive Maintenance

In daily operations, human intervention is often necessary to address minor issues that can disrupt AMR operations. Common tasks include:

• Clearing Obstacles: Removing debris like plastic or wood fragments that can block wheels or sensors.

• Sensor Cleaning: Ensuring sensors are free from dust to maintain accurate navigation.

• Minor Repairs: Fixing components such as bumpers or other small parts.

These tasks are typically straightforward and can be handled promptly to minimize downtime.

Regular Maintenance

Beyond daily checks, regular maintenance is crucial for the longevity and efficiency of the robot fleet. This includes:

• Routine Inspections: Conducted weekly or daily to detect unusual behaviors, sounds, or vibrations.

• Scheduled Maintenance: Performed biannually or annually, involving comprehensive checks, part replacements, and compliance with legal requirements like Unfallverhütungsvorschriften (UVV) inspections.

Proper documentation of all maintenance activities is vital for tracking the health of the fleet and planning future interventions.

Impact of Environmental Factors

The maintenance needs of AMRs are influenced by environmental conditions:

• Cleanliness: A clean operating environment reduces the likelihood of debris-related issues.

• Floor Condition: Well-maintained floors prevent unnecessary wear and tear on the robots.

Regular cleaning of the facility and prompt replacement of broken navigation markers, such as QR codes, are essential to support optimal robot performance.

Time Investment in Maintenance

The time required for maintenance varies based on several factors, including fleet size and operational conditions. For example:

• Fleet of 50 Robots: If each robot requires 10 minutes of maintenance per week, the total annual maintenance time is approximately 433 hours.

• Fleet of 200 Robots: Under the same conditions, the total annual maintenance time would be about 1,733 hours.

Alternatively, with a lower maintenance requirement of 30 minutes per robot per year, a fleet of 50 robots would need 25 hours annually, and a fleet of 200 robots would require 100 hours. This, however, means that in most cases the Standard Operating Procedures (SOPs) provided by the robot Original Equipment Manufacturer (OEM) are not followed strictly, and that the operator or service provider takes the risk of downtime and warranty loss (which in many cases is accepted).

Role of Service Providers

Service providers often offer full-service contracts, handling most maintenance activities. They may schedule regular visits and perform tasks proactively to optimize travel and labor costs. However, operators should ensure that all maintenance activities are well-documented, including parts replaced and services performed. This documentation aids in assessing maintenance effectiveness and identifying areas for improvement.

Leveraging Condition Monitoring

Implementing condition monitoring systems provides real-time insights into the performance and health of the robot fleet. Benefits include:

• Proactive Maintenance: Identifying potential issues before they lead to failures.

• Performance Analytics: Monitoring metrics such as speed, error rates, and unplanned stops to optimize operations.

• Usage-Based Maintenance: Transitioning from scheduled to usage-based maintenance, allowing for more accurate and timely interventions.

For service providers, condition monitoring enables more precise scheduling of maintenance activities, reducing costs or travel and improving service quality. Maintaining an accurate inventory of spare parts further enhances efficiency by ensuring that necessary components are available when needed during a site visit, minimizing additional site visits.

In conclusion, effective maintenance of large AMR fleets requires a combination of daily oversight, regular inspections, and strategic use of condition monitoring systems. By adopting these practices, operators and service providers can ensure the reliability and efficiency of their robotic operations.