Maintenance, repair, and overhaul of robotic systems

1. Introduction

This paper describes fundamental aspects of maintenance, repair, and overhaul (MRO) of robotic systems (RS), going through definitions, industries, performance indicators, data analytics, software solutions, and logistics and supply chain needs. When discussing MRO and RS, one can distinguish two approaches:

1) Maintenance, repair, and overhaul of robotic systems (RS MRO) enhances operational efficiency, reduces downtime, and improves the overall reliability of robotic systems. It is driven by the increasing need for operational excellence and efficiency in industries that rely heavily on robotic systems.

2) Using robotic systems for MRO operations focuses on leveraging robotic systems to automate and enhance various MRO activities in aircraft maintenance, manufacturing, and other industrial settings. This includes tasks like inspections, repairs, cleaning, and component handling.

This study focuses on the first approach and addresses the following questions: What are the challenges of implementing RS MRO operations? What types of maintenance strategies are used? What are the key variables that are used to monitor the efficiency and cost-effectiveness of RS MRO operations? How are data analytics used to improve RS MRO operations? What types of software are available to support these operations? For these reasons, it brings new and interesting developments, contributing to those working in the related areas considered herein.

For this study, the authors reviewed the limited scholarly research on RS MRO and corporate websites that describe the current views and practices of RS developers, operators, and MRO solution providers. AI search tools, including Gemini and ChatGPT, were used to find and analyze these websites. The contents were then revised, organized and structured to present a snapshot of the state-of-the-art in RS MRO, which can motivate and inform future research and development activities.

This paper is organized as follows: Section 2 explains some of the characteristics of RS MRO in practice. Section 3 discusses general procedures, challenges and difficulties, variables and KPIs in implementing RS MRO. Section 4 describes data analytics and software solutions for RS MRO. Section 5 brings a brief analysis on MRO logistics and supply chain integration. Lastly, Section 6 presents a summary and conclusions.

2. Maintenance of robotic systems

Robotic systems are being maintained, repaired, and overhauled in many real-world applications [1-22]:

– Robotic arms performing welding or assembly tasks in an automotive factory require regular maintenance, including lubrication, cleaning, inspection, and software updates.

– Surgical Robots (robots used in surgery), like the da Vinci Surgical System, require stringent maintenance to ensure their precision and reliability. This includes regular calibration, software updates, and preventive servicing.

– Rehabilitation and Physical Therapy Robots (robots used to assist patients in therapy) need regular maintenance to ensure they function correctly and safely.

– Cleaning and Disinfection Robots (autonomous robots are used to clean and disinfect healthcare facilities, improving efficiency and infection control) need regular maintenance, including checking and cleaning sensors, updating navigation systems, and ensuring proper operation of disinfection components.

– Autonomous Mobile Robots (AMRs) are used for tasks like order fulfillment and inventory management, require regular maintenance to ensure their mobility, navigation systems, and sensor accuracy. Predictive maintenance strategies, using AI and machine learning, monitor AMR performance and schedule maintenance proactively, reducing errors and enhancing supply chain efficiency.

These types of robots (and many others) are being used in many industries and activities, including industrial manufacturing, automotive manufacturing, electronics assembly and testing, pharmaceuticals, healthcare, textiles and clothing manufacturing, food and beverage manufacturing, agriculture, construction, mining, energy, military, public safety, logistics and warehousing, and retail [23-28].

Robotics systems are complicated machines that combine mechanical actuators, electrical systems, computing, and many types of sensors [30], and robots can fail in many ways. Table 2 summarizes common robot malfunctions and typical causes [30]. Wang and Christensen [15] described battery failures, auto charging problems, mechanical failures, device driver failures, network connectivity issues, and software problems on a mobile tour guide robot. Inside a robot motor, the brake, bearings, encoders, and other components can fail [32].

Correspondingly, a wide variety of maintenance activities are required to prevent or repair robot failures. Organizations are using both preventive maintenance strategies (cf. Table 1) and predictive maintenance strategies (see Section 3.1) for their robotic systems [1], [3]. A robot’s computer requires data backups and software updates [14]. Robot maintenance requires skills in software, electrical, mechanical, and control engineering in order to diagnose the causes of failures and perform the necessary repairs.

The costs of robot maintenance include training staff to perform the maintenance activities, purchasing and managing spare parts, and repairing robots when they fail [34], [35]. Because some industrial robots are large and powerful, accidents such as collisions, crushing, and trapping can occur [36], and maintenance staff need to follow safety guidelines and guidelines [37].

3. Implementation, variables and performance measures for MRO of robotic systems

To maximize robot reliability, availability, and productivity, effective RS MRO is essential to reduce robot failures and delays due to MRO operations. Implementing RS MRO operations involves technical, personnel, data management, financial, and logistics challenges, as detailed below [10], [38-47]:

1) Technical Complexity and Integration Issues:

– Integrating robots with existing systems and workflows can be technically challenging due to sophisticated configurations and potential compatibility issues.

– The intricate design and numerous components of robotic systems can make it difficult to pinpoint the root cause of failures and accurately predict maintenance needs.

– Legacy systems or highly customized processes within MRO operations can complicate the integration of new robotics technology.

– Choosing modular systems that can be easily integrated with existing infrastructure and adhering to interoperability standards can help address these challenges.

2) The personnel challenges involve the need to work with new technologies:

– Integrating new technologies often requires a shift in workforce dynamics and can lead to resistance from employees concerned about job displacement.

– There can be a shortage of skilled personnel required to operate, maintain, and repair complex robotic systems.

– Training employees on new systems and technologies can be time-consuming and costly.

– Involving employees in the planning and implementation process, providing comprehensive training programs, and implementing change management strategies can help overcome resistance and facilitate smoother adoption.

3) Data Management and Quality:

– Effective MRO data management is crucial for smooth operations in asset-heavy industries.

– MRO data can be plagued with challenges such as duplication, unstructured data, incomplete information, and conflicting data.

– Predictive maintenance relies on the analysis of large volumes of data, requiring robust data management infrastructure for storage, bandwidth, and computational resources.

– Data quality and integrity are critical for accurate predictions and can be undermined by inaccuracies, inconsistencies, or errors in the collected data.

– Regulatory and ethical concerns, such as safety standards, data privacy, and ethical considerations, are also important factors to address during implementation, particularly in sensitive sectors like healthcare and hospitality.

4) Cost and Investment:

– The complexity of robotic systems also increases the initial and recurring costs of RS MRO operations. Exploring leasing and financing options, government grants and subsidies, and collaborative partnerships can help organizations manage the financial burden of adopting robotic systems (and their respective MRO support).

5) MRO Logistics and Supply Chain Management.

– Purchasing and managing the spare parts, increase availability and reduce maintenance costs [13]. Parts classification is a useful strategy for supplies, and consumables needed for RS MRO operations is another challenging domain. Generally, effective MRO logistics can prioritizing the mechanical parts, sensors, and electronics that robots use [34]. Typically, organizations use three categories: (1) high-criticality parts are essential for the robot’s operation, such as motors, control boards, and sensors; (2) medium-criticality parts (such as wheels or secondary actuators) affect the robot’s performance but don’t cause immediate shutdowns; and (3) low-criticality parts are inexpensive wear-and-tear components, such as belts and housings, that are easy to replace. Different inventory management policies are used to manage these different types of parts (sometimes called A, B, and C parts) [48], [49].

Organizations can address these challenges through careful planning, vendor support, training programs, predictive maintenance, and ensuring regulatory compliance to effectively integrate robotic systems into their current or new MRO operations.

4. Data analytics and software solutions to RS MRO

5. MRO logistics and supply chain integration

With industries using robotic systems to improve productivity, quality and reliability more and more every year, maintaining their operation the best way possible is a challenge to the MRO area. The key trends for future RS MRO should include the integration of logistics operation, or more widely speaking, the supply chain surrounding the MRO tasks, in order to better maintain and operate robotic systems. Effective Logistics and Supply Chain Management (SCM) are crucial for optimizing MRO of robotic systems but does not seem to get much attention. Key aspects and analyses should consider [13], [34], [35], [81]-[84]:

1) MRO Inventory Management:

– Balancing Availability and Cost: MRO inventory management is about having the right parts and tools available when needed while minimizing excess stock that ties up capital and incurs storage costs.

– Challenges are related to inconsistent maintenance planning, poor data quality, and loose purchasing controls can lead to inefficiencies and increased costs. On the other hand, best practices can focus on:

a) Leveraging AI-powered tools and data analytics can help identify slow-moving and obsolete inventory, forecast demand, and automate reorder processes.

b) Categorize parts based on criticality (high-criticality, medium-criticality, and low-criticality) to prioritize stocking and ensure essential components are always available.

c) Standardize parts across different robot models where possible to reduce complexity in inventory management and improve repair times.

d) Maintain a digital inventory of spare parts using a Computerized Maintenance Management System (CMMS) or other software for real-time tracking.

2) Spare Parts Management: Ensuring Continuous Availability. In this sense, spare parts management is crucial for minimizing downtime due to equipment failures. Other as aspects to be considered are:

– Integrate spare parts management with predictive maintenance to ensure parts are ordered before failure occurs.

– Implement Just-in-Time (JIT) ordering for non-critical parts to reduce inventory costs, while maintaining a small stock of essential components for high-criticality items.

– Establish strong relationships with suppliers to ensure timely delivery of parts.

– Track part lifecycle and usage, by monitoring when parts were last replaced, their performance, and when they are likely to fail to guide future decisions and optimize stocking levels.

– Monitor for obsolescence, keeping track of which components are still supported by manufacturers and which may need to be phased out.

3) Maintenance Programs and Schedules:

– Proactive Planning by developing maintenance plans that proactively identify and address potential issues, minimizing unexpected breakdowns.

– Proper coordination and scheduling of maintenance and service needs are vital, along with clear communication about timelines and addressing potential supply chain issues.

– Employ data analytics to predict maintenance needs, optimize robot deployment, and streamline operations based on insights.

4) Real-Time Tracking and Visibility:

– Real-time tracking of MRO operations improves efficiency, optimizes response strategies, and increases productivity by eliminating redundant tasks.

– Providing a holistic view of processes helps sharpen inventory forecasting, reduce costs, and prevent system failures.

– Real-time tracking tools enable proactive responses and facilitate more efficient MRO operations.

5) Import/Export Strategies for MRO Supply Chain:

– Develop well-planned import and export procedures to manage the sourcing and importing of parts from global suppliers, minimizing delays due to customs, tariffs, and taxes.

– Form strong partnerships with foreign suppliers based on openness and trust to ensure on-time delivery, quality, and compliance with regulations.

– Utilize technology like AI and digitalization to streamline customs procedures, enable real-time tracking, and enhance communication between suppliers and logistics partners.

6) Cost Optimization: Optimize MRO supply chain operations to improve time efficiency and cost savings through:

– Inventory Management: Better inventory management reduces overall operating costs.

– Consolidating Shipments: Consolidating international shipments can decrease per-unit costs.

– Optimizing Logistics: Strategic product scheduling reduces the need for expensive expedited shipping.

– Negotiating Favorable Terms: Strong supplier relationships can lead to discounts and favorable pricing.

6. Conclusions

Based on a review of relevant research and online information, this paper reviewed the state-of-the-art in RS MRO, which is increasingly important as organizations in many industries adopt and deploy robotic systems in their operations. Although similar in some ways to general MRO activities, the technical complexity of robotic systems increases the challenges of RS MRO and the need for new approaches, including new performance measures, new types of data analytics, new types of software for managing a fleet of robots, and a holistic logistics/supply chain approach for better RS MRO.

Other industries that currently do not rely on RS but will do eventually, such as Hospitality and Tourism, Creative Arts and Entertainment, Education, Domestic and Personal Assistance, Construction, and Environmental Cleanup [76], [81], [85], [95] will have to think carefully about their needs regarding RS MRO, considering that the future of robotics in these emerging sectors will likely involve greater integration, driving innovation and efficiency, and potentially creating new opportunities alongside humans.

The implementation of larger, more capable AI models will give organizations more tools for managing and improving MRO operations. On the other hand, future robotic systems that use AI models and have more autonomy than those deployed today will create new MRO challenges. Autonomous systems often need to communicate with the AI models that cannot be run with onboard computers, which increases the importance of maintaining the advanced technology (such as 5G communication networks) for fast, reliable network connections [95]. Diagnosing the problems caused by these AI models (such as control system faults) will be difficult due to their black-box nature and the limitations of explainable AI (XAI) to date [97].

As robotic systems move from experiments to essential equipment, the spare parts logistics and supply chain management will become more important in more industries and organizations. Hence, future RS MRO studies will be focusing on key aspects and analyses considering, for instance: MRO Inventory Management, Spare Parts Management, Maintenance Programs and Schedules, Real-Time Tracking and Visibility, Import/Export Strategies for MRO Supply Chain, and Cost Optimization. Among these, it is especially important to manage the risk of disruptions such as diminishing manufacturing sources and material shortages through appropriate sourcing strategies [98].

The future of robotics in these emerging sectors will likely involve greater integration, driving innovation and efficiency, and potentially creating new opportunities alongside humans and by implementing robust logistics and supply chain strategies along with AI and advanced analytics, organizations will be able to ensure operational excellence, minimize downtime, reduce costs, and ultimately enhance the overall efficiency and resilience of their RS MRO operations at just the right time.