Click Image to Enlarge

One interesting feature of R2-D2 and BB-8 is how they communicate nonverbally, using expressive beeps and whistles for classic communication functions, such as initiating communication and signalling that they are paying attention, an interesting precursor of M2M interaction in complex maintenance actions. However, the applicability of R2-D2 and BB-8 to maintenance is questionable, and what they may inspire in the next generation of roboticists is unknown. But simply thinking in this direction raises an interesting question: How would a real-life repair robot be different from the admittedly more fanciful R2-D2 and BB-8?
Autonomous robots, i.e., freely moving robots that operate without direct human supervision, are expected to function in complex, unstructured environments and make decisions on what action to take in any given situation. They gain information on their surroundings via sensors. The information is processed in the robot’s “brain,” consisting of one or more microcontrollers; after processing, motor signals are sent to the actuators (motors) of the robot, and it can act. Thus, the “brain” is the system that provides an autonomous robot, however simple, with the ability to process information and decide which actions to take.
The main difficulty is training robots to perform maintenance effectively in different and little-known environments.
Autonomous robots, including unmanned aerial vehicles (UAVs) and remotely operated vehicles, are currently used in various industrial settings for inspection and maintenance. Inspection is a simple observation action and thus is the simplest task for maintenance robots. As autonomous robots can be programmed for repetitive and specific tasks, the development of inspection operations for industrial assets using UAVs is relatively mature.

Features of maintenance robots

Many different robots have already been developed to handle various situations in industry and transportation sectors.
However, most are limited to special situations or applications. To execute the desired tasks, autonomous robots, as well as all other technical systems, have to fulfil certain requirements. The requirements and their importance and focus depend on the individual application or tasks. Nevertheless, we can formulate a general set of requirements as follows:
Velocity and mobility: Vehicle speed and dynamics (ability to move) are two main aspects of robot design. Depending on the dimension of the asset, the robot may have to reach a relatively high velocity for sufficiently fast navigation between inspection areas or similar points of action. Another requirement is related to the desired manipulation and positioning capabilities of the system. This includes the precision of locomotion, as some inspection sensors need to be moved in a smooth and continuous way over the surface. The robot may also need to move sideways or to turn 360° to position sensors or tools.
The system dynamics should be able to handle the various terrains and reach all positions of the asset.
Payload: Depending on the application, the system must be able to carry payloads of different weights. For example, in the case of steel piping, a payload of 5 kg or more is mandatory to carry ultrasonic inspection sensors. This requires a much bigger robot than a system which just needs a simple camera with a weight of several hundred grams. In other words, the dimension, adhesion, and motion components of the robot need to be adapted for the application.
Reliability and safety: An important non-functional aspect is the robustness of the system. If the autonomous robot fails frequently during one inspection task, it is not usable in practice. The requirements of reliability and safety include robust hardware, optimal controllers, and methods to detect and handle hazardous situations and to recover from them.
Usability: Velocity, manoeuvrability, and the capability of carrying a certain payload are important, but they are only the basis of the general operability of the system. To bring a robotic system into application, it has to be more powerful, more efficient, and less dangerous than common approaches. This includes aspects of maintainability and a broad range of other tasks.
Therefore, it must be able to carry different payloads (e.g., inspection sensors or tools) depending on the desired task, parts need to be easily replaceable, and the operation must be faster and less complicated than existing approaches. Aspects like energy consumption, weight, or dimension of the system can be important as well.

Click Image to Enlarge

Types of robots in maintenance – now and in the future

The vision of using drones and robots in maintenance and inspection tasks is already materializing. Drones are deployed in many industries not only for asset inspections but also for security and surveillance. Most deployments are in utilities and power generation, oil and gas, or infrastructure management, but the aero industry is deploying UAVs to inspect aircraft. This includes the possibility of launching a UAV every time an aircraft approaches a gate, as a means of monitoring potential damage.
Robots often perform tasks that are difficult, unsafe, or tedious for humans. In fact, in any industry, safety and cost are two of the most significant drivers of operation and maintenance and are always important. Many industrial work areas are hazardous, so measures must be taken to secure the safety of users. For instance, working on energised high-voltage transmission lines, sometimes several metres in the air, can make the consequences of a mistake deadly. Unmanned systems have the potential to reduce the risk exposure of the operational workforce and improve the safety of personnel.
The use of drones, robots, and UAVs will rapidly become more popular and commonplace because of their ability to decrease costs and keep human workers safe. They are becoming more versatile and useful as their functionalities and intelligence continue to be improved. For instance, UAV vendors are working towards releasing cognitive drones, which will be able to intelligently tune the rate of their data collection depending on the context of the inspection. For example, cognitive drones will be able to collect more images of damaged parts by adapting their operation whenever they identify a damaged part.

In the future, it’s likely that we will see inspections and maintenance tasks carried out by voice-guided robots. We’ll also see actuator robots complete routine field inspections, thanks to a host of attractive features, such as flexibility, adaptability, and a range of payloads, while human workers turn to safer, supervisory roles. Sensors on board will include high-resolution digital and infrared cameras, Light Detection and Ranging (LiDAR), geographic information systems (GIS), sonar sensors, and ultrasonic sensors. Drones can be equipped with forward-looking infrared (FLIR), or ultraviolet sensors can detect hot spots or corona discharge on conductors and insulators, signalling a potential defect or weakness in the component. LiDAR can be integrated with drones to survey a proposed right-of-way, show the infrastructure situation when seismic conditions are changing, or monitor the encroachment of vegetation. There are many more potential uses, and these examples are only the tip of the iceberg.

At present, most UAVs are remotely operated by expert pilots, but the next phase of UAV technology will include “smarter” machines that fly autonomously. This is already a reality in the military environment to some extent and is quickly entering industry. The new technology will allow UAVs to sense and avoid other objects in their path, recognise features or components through various sensors (including cameras) using complex software algorithms, such as image processing algorithms, and achieve situational awareness. This will foster calculated decision-making, such as initiating focused inspections, issuing work orders for repairs, and starting maintenance work with the same robot or another autonomous robot integrated in the system.
In the not-so-distant future, there will be a much wider variety of robots depending on the features needed and the task to be performed. Drones and UAV are cheap and affordable for inspection and minor interventions, but if a higher payload and stability are required, a mobile platform equipped with robotic arms might be an option. Robotic platforms represent an opportunity to access hard-to-reach assets and perform the required tasks.
Perhaps it’s time to start thinking about robot maintainability. This could represent a new discipline where assets are designed to be maintained by robots and not by humans. At the moment, most assets are designed for human size and tools. In the future, we may switch to robotic capabilities and dimensions when we design maintainability policies and methodologies.

Fields of application

Remotely controlled and autonomous inspection and maintenance devices are used in different sectors for different purposes, but the inspection of remote and difficult-to-access environments seems to be the main application. For example, UAVs are used for inspection in assets in oil and gas industries, and underwater robots are used for maintenance on offshore platforms.
Oil and gas companies are interested in UAVs for inspection and exploration purposes, as they offer a less expensive means of surveying the terrain where pipelines are installed. They also offer a way to patrol the pipes to look for disruptions or leaks caused by accidents such as landslides or lightning strikes or for damage caused by vehicles or falling trees. In certain areas of the world, sabotage is not uncommon, so they look for this as well.

Click Image to Enlarge

The energy sector has been a pioneer in the application of robots for inspection and maintenance. Power suppliers have traditionally inspected power lines for encroaching trees, damage to structures, and deterioration of insulators by having employees traverse the lines on foot and climb the poles. This is time-consuming and arduous, with a considerable element of risk. Things changed when companies began to send out manned helicopters; crews used binoculars and thermal imagers to detect the breakdown of insulators. Using UAVs to inspect power lines promises to further revolutionize the industry. UAVs offer lower costs, do not create a hazard for aircrews, can operate in more adverse weather conditions, and are less obtrusive to neighbouring communities.
UAVs could be used in critical infrastructure inspections and for certain maintenance purposes by traffic infrastructure agencies. In addition to being less expensive to operate than manned aircraft, they are more covert and will avoid distracting drivers. Rail, road, airport, river and port authorities, and water boards could use UAVs to monitor point and linear assets to assure health integrity and functionality.

Can robots do maintenance?

Industry is moving towards new and more sophisticated inspection, condition monitoring, analysis, and maintenance technologies. This evolution, together with the development of autonomous robots, will provide a platform to maintain all kinds of assets more efficiently. The current technology is promising and will reach maturity soon but integration with humans remains a key concern.
The importance of autonomous inspections and maintenance is increasing because many assets are aging. At the same time, asset managers are struggling to operate effectively and maintain costs, as skilled maintainers are retiring, and finding a labour force for maintenance is challenging. Reliable inspection and maintenance methodologies incorporating new technologies would facilitate cost-effective and efficient asset management.
Various industries, especially those dealing with high-risk activities, are already using remotely operated robots for some maintenance activities, for instance, marine repairs (repairs of ships offshore, offshore oil and gas platform maintenance, deep sea pipeline and cable maintenance), oil refinery repairs, nuclear power plant repairs etc. At the moment, because of the limited development of robots for maintenance purposes, complete maintenance cannot be performed. New assets should incorporate ways to be maintained by robots and not humans, thus changing the design of our machines and the way we perform maintenance.

Professors Diego Galar, Ramin Karim and Uday Kumar from the University of Luleå, Sweden