Mobile robot

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A robotic vacuum cleaner Building Fairs Brno 2011 (217).jpg
A robotic vacuum cleaner

A mobile robot is an automatic machine that is capable of locomotion. [1] Mobile robotics is usually considered to be a subfield of robotics and information engineering. [2]

Contents

Mobile robots have the capability to move around in their environment and are not fixed to one physical location. Mobile robots can be "autonomous" (AMR - autonomous mobile robot) which means they are capable of navigating an uncontrolled environment without the need for physical or electro-mechanical guidance devices. [3] Alternatively, mobile robots can rely on guidance devices that allow them to travel a pre-defined navigation route in relatively controlled space. [4] By contrast, industrial robots are usually more-or-less stationary, consisting of a jointed arm (multi-linked manipulator) and gripper assembly (or end effector), attached to a fixed surface. The joint.

Mobile robots have become more commonplace in commercial and industrial settings. Hospitals have been using autonomous mobile robots to move materials for many years. Warehouses have installed mobile robotic systems to efficiently move materials from stocking shelves to order fulfillment zones. Mobile robots are also a major focus of current research and almost every major university has one or more labs that focus on mobile robot research. [5] Mobile robots are also found in industrial, military and security settings.

The components of a mobile robot are a controller, sensors, actuators and power system. [3] The controller is generally a microprocessor, embedded microcontroller or a personal computer (PC). The sensors used are dependent upon the requirements of the robot. The requirements could be dead reckoning, tactile and proximity sensing, triangulation ranging, collision avoidance, position location and other specific applications. [6] Actuators usually refer to the motors that move the robot can be wheeled or legged. To power a mobile robot usually we use DC power supply (which is battery) instead of AC.

Classification

Mobile robots may be classified by:[ citation needed ]

Mobile robot navigation

There are many types of mobile robot navigation:

Manual remote or tele-op

A manually teleoperated robot is totally under control of a driver with a joystick or other control device. The device may be plugged directly into the robot, may be a wireless joystick, or may be an accessory to a wireless computer or other controller. A tele-op'd robot is typically used to keep the operator out of harm's way. Examples of manual remote robots include Robotics Design's ANATROLLER ARI-100 and ARI-50, Foster-Miller's Talon, iRobot's PackBot, and KumoTek's MK-705 Roosterbot.

Guarded tele-op

A guarded tele-op robot has the ability to sense and avoid obstacles but will otherwise navigate as driven, like a robot under manual tele-op. Few if any mobile robots offer only guarded tele-op. (See Sliding Autonomy below.)

Line-following Car

Some of the earliest Automated Guided Vehicles (AGVs) were line following mobile robots. They might follow a visual line painted or embedded in the floor or ceiling or an electrical wire in the floor. Most of these robots operated a simple "keep the line in the center sensor" algorithm. They could not circumnavigate obstacles; they just stopped and waited when something blocked their path. Many examples of such vehicles are still sold, by Transbotics, FMC, Egemin, HK Systems and many other companies. These types of robots are still widely popular in well known Robotic societies as a first step towards learning nooks and corners of robotics.

Autonomously randomized robot

Autonomous robots with random motion basically bounce off walls, whether those walls are sensed.

Autonomously guided robot

Robot developers use ready-made autonomous bases and software to design robot applications quickly. Shells shaped like people or cartoon characters may cover the base to disguise it. SmMT400 autonomous robot base with Motivity.jpg
Robot developers use ready-made autonomous bases and software to design robot applications quickly. Shells shaped like people or cartoon characters may cover the base to disguise it.

An autonomously guided robot knows at least some information about where it is and how to reach various goals and or waypoints along the way. "Localization" or knowledge of its current location, is calculated by one or more means, using sensors such motor encoders, vision, Stereopsis, lasers and global positioning systems.

Positioning systems often use triangulation, relative position and/or Monte-Carlo/Markov localization to determine the location and orientation of the platform, from which it can plan a path to its next waypoint or goal. It can gather sensor readings that are time- and location-stamped. Such robots are often part of the wireless enterprise network, interfaced with other sensing and control systems in the building. For instance, the PatrolBot security robot responds to alarms, operates elevators and notifies the command center when an incident arises. Other autonomously guided robots include the SpeciMinder and the TUG delivery robots for the hospital.[ citation needed ]

Sliding autonomy

More capable robots combine multiple levels of navigation under a system called sliding autonomy. Most autonomously guided robots, such as the HelpMate hospital robot, also offer a manual mode which allows the robot to be controlled by a person. The Motivity autonomous robot operating system, which is used in the ADAM, PatrolBot, SpeciMinder, MapperBot and a number of other robots, offers full sliding autonomy, from manual to guarded to autonomous modes.

History

DateDevelopments
1939–1945During World War II the first mobile robots emerged as a result of technical advances on a number of relatively new research fields like computer science and cybernetics. They were mostly flying bombs. Examples are smart bombs that only detonate within a certain range of the target, the use of guiding systems and radar control. The V1 and V2 rockets had a crude 'autopilot' and automatic detonation systems. They were the predecessors of modern cruise missiles.
1948–1949 W. Grey Walter builds Elmer and Elsie, two autonomous robots called Machina Speculatrix because these robots liked to explore their environment. Elmer and Elsie were each equipped with a light sensor. If they found a light source they would move towards it, avoiding or moving obstacles on their way. These robots demonstrated that complex behaviour could arise from a simple design. Elmer and Elsie only had the equivalent of two nerve cells. [10]
1961–1963The Johns Hopkins University develops 'Beast'. Beast used a sonar to move around. When its batteries ran low it would find a power socket and plug itself in.
1969Mowbot was the very first robot that would automatically mow the lawn. [11]
1970The Stanford Cart line follower was a mobile robot that was able to follow a white line, using a camera to see. It was radio linked to a large mainframe that made the calculations. [12]
At about the same time (1966–1972) the Stanford Research Institute is building and doing research on Shakey the Robot, a robot named after its jerky motion. Shakey had a camera, a rangefinder, bump sensors and a radio link. Shakey was the first robot that could reason about its actions. This means that Shakey could be given very general commands, and that the robot would figure out the necessary steps to accomplish the given task.
The Soviet Union explores the surface of the Moon with Lunokhod 1, a lunar rover.
1976In its Viking program the NASA sends two unmanned spacecraft to Mars.
1980The interest of the public in robots rises, resulting in robots that could be purchased for home use. These robots served entertainment or educational purposes. Examples include the RB5X, which still exists today and the HERO series.
The Stanford Cart is now able to navigate its way through obstacle courses and make maps of its environment.
Early 1980sThe team of Ernst Dickmanns at Bundeswehr University Munich builds the first robot cars, driving up to 55 mph on empty streets.
1983Stevo Bozinovski and Mihail Sestakov control a mobile robot by parallel programming, using multitasking system of IBM Series/1 computer. [13]
1986Stevo Bozinovski and Gjorgi Gruevski control a wheeled robot using speech commands. The project was supported by the Macedonian Association for Scientific Activities. [14]
1987 Hughes Research Laboratories demonstrates the first cross-country map and sensor-based autonomous operation of a robotic vehicle. [15]
1988Stevo Bozinovski, Mihail Sestakov, and Liljana Bozinovska control a mobile robot using EEG signals. [16] [17]
1989Stevo Bozinovski and his team control a mobile robot using EOG signals. [17]
1989 Mark Tilden invents BEAM robotics.
1990s Joseph Engelberger, father of the industrial robotic arm, works with colleagues to design the first commercially available autonomous mobile hospital robots, sold by Helpmate. The US Department of Defense funds the MDARS-I project, based on the Cybermotion indoor security robot.
1991 Edo. Franzi, André Guignard and Francesco Mondada developed Khepera, an autonomous small mobile robot intended for research activities. The project was supported by the LAMI-EPFL lab.
1993–1994 Dante I [18] and Dante II [19] were developed by Carnegie Mellon University. Both were walking robots used to explore live volcanoes.
1994With guests on board, the twin robot vehicles VaMP and VITA-2 of Daimler-Benz and Ernst Dickmanns of UniBwM drive more than one thousand kilometers on a Paris three-lane highway in standard heavy traffic at speeds up to 130 km/h. They demonstrate autonomous driving in free lanes, convoy driving, and lane changes left and right with autonomous passing of other cars.
1995Semi-autonomous ALVINN steered a car coast-to-coast under computer control for all but about 50 of the 2850 miles. Throttle and brakes, however, were controlled by a human driver.
1995In the same year, one of Ernst Dickmanns' robot cars (with robot-controlled throttle and brakes) drove more than 1000 miles from Munich to Copenhagen and back, in traffic, at up to 120 mph, occasionally executing maneuvers to pass other cars (only in a few critical situations a safety driver took over). Active vision was used to deal with rapidly changing street scenes.
1995The Pioneer programmable mobile robot becomes commercially available at an affordable price, enabling a widespread increase in robotics research and university study over the next decade as mobile robotics becomes a standard part of the university curriculum.
1996Cyberclean Systems develops the first fully autonomous vacuum cleaning robot that self-charged, operated elevators and vacuumed hallways with no human intervention.
1996–1997 NASA sends the Mars Pathfinder with its rover Sojourner to Mars. The rover explores the surface, commanded from earth. Sojourner was equipped with a hazard avoidance system. This enabled Sojourner to autonomously find its way through unknown martian terrain.
1999 Sony introduces Aibo, a robotic dog capable of seeing, walking and interacting with its environment. The PackBot remote-controlled military mobile robot is introduced.
2001Start of the Swarm-bots project. Swarm bots resemble insect colonies. Typically they consist of a large number of individual simple robots, that can interact with each other and together perform complex tasks. [20]
2002 Roomba appears, a domestic autonomous mobile robot that cleans the floor.
2002Nevena Bozinovska, Gjorgi Jovancevski, and Stevo Bozinovski carried out Internet-based robot control in a distance learning robotics class. A mobile robot in United States, South Carolina State University, was controlled by students in Europe, Sts. Cyril and Methodius University. [21]
2003Axxon Robotics purchases Intellibot, manufacturer of a line of commercial robots that scrub, vacuum, and sweep floors in hospitals, office buildings and other commercial buildings. Floor care robots from Intellibot Robotics LLC operate completely autonomously, mapping their environment and using an array of sensors for navigation and obstacle avoidance.
2004 Robosapien, a biomorphic toy robot designed by Mark Tilden is commercially available.
In 'The Centibots Project' 100 autonomous robots work together to make a map of an unknown environment and search for objects within the environment. [22]
In the first DARPA Grand Challenge competition, fully autonomous vehicles compete against each other on a desert course.
2005 Boston Dynamics creates a quadruped robot intended to carry heavy loads across terrain too rough for vehicles.
2006 Sony stops making Aibo and HelpMate halts production, but a lower-cost PatrolBot customizable autonomous service robot system becomes available as mobile robots continue the struggle to become commercially viable. The US Department of Defense drops the MDARS-I project, but funds MDARS-E, an autonomous field robot. TALON-Sword, the first commercially available robot with grenade launcher and other integrated weapons options, is released. [23] Honda's Asimo learns to run and climb stairs.
2007In the DARPA Urban Grand Challenge, six vehicles autonomously complete a complex course involving manned vehicles and obstacles. [24] Kiva Systems robots proliferate in distribution operations; these automated shelving units sort themselves according to the popularity of their contents. The Tug becomes a popular means for hospitals to move large cabinets of stock from place to place, while the Speci-Minder [25] with Motivity begins carrying blood and other patient samples from nurses' stations to various labs. Seekur, the first widely available, non-military outdoor service robot, pulls a 3-ton vehicle across a parking lot, [26] drives autonomously indoors and begins learning how to navigate itself outside. Meanwhile, PatrolBot learns to follow people and detect doors that are ajar.
2008Boston Dynamics released video footage of a new generation BigDog able to walk on icy terrain and recover its balance when kicked from the side.
2010The Multi Autonomous Ground-robotic International Challenge has teams of autonomous vehicles map a large dynamic urban environment, identify and track humans and avoid hostile objects.
2016The Path following of autonomous mobile robot using passive RFID tags is a new method to follow the path using RFID tags. It is proved that the robot always reaches the destination as close as the distance measurement error even if the distance and angular measurements are not exact. It is also capable of choosing right path among multiple paths.
2016The Multi-Function Agile Remote-Controlled Robot (MARCbot) is for the first time used by US police to kill a sniper who killed 5 police officers [27] in Dallas, Texas, which raises ethical questions regarding the use of drones and robots by police as instruments of lethal force against a perpetrator.

During the NASA Sample Return Robot Centennial Challenge, a rover, named Cataglyphis, successfully demonstrated autonomous navigation, decision-making, and sample detection, retrieval, and return capabilities. [28]

2017Within the ARGOS Challenge robots are developed to work under extreme conditions on offshore oil and gas installations. [29]

See also

Related Research Articles

<span class="mw-page-title-main">Robot</span> Machine capable of carrying out a complex series of actions automatically

A robot is a machine—especially one programmable by a computer—capable of carrying out a complex series of actions automatically. A robot can be guided by an external control device, or the control may be embedded within. Robots may be constructed to evoke human form, but most robots are task-performing machines, designed with an emphasis on stark functionality, rather than expressive aesthetics.

An autonomous robot is a robot that acts without recourse to human control. The first autonomous robots environment were known as Elmer and Elsie, which were constructed in the late 1940s by W. Grey Walter. They were the first robots in history that were programmed to "think" the way biological brains do and meant to have free will. Elmer and Elsie were often labeled as tortoises because of how they were shaped and the manner in which they moved. They were capable of phototaxis which is the movement that occurs in response to light stimulus.

Robotic control is the system that contributes to the movement of robots. This involves the mechanical aspects and programmable systems that makes it possible to control robots. Robotics can be controlled by various means including manual, wireless, semi-autonomous, and fully autonomous.

<span class="mw-page-title-main">Swarm robotics</span> Coordination of multiple robots as a system

Swarm robotics is an approach to the coordination of multiple robots as a system which consist of large numbers of mostly simple physical robots. ″In a robot swarm, the collective behavior of the robots results from local interactions between the robots and between the robots and the environment in which they act.″ It is supposed that a desired collective behavior emerges from the interactions between the robots and interactions of robots with the environment. This approach emerged on the field of artificial swarm intelligence, as well as the biological studies of insects, ants and other fields in nature, where swarm behaviour occurs.

Wireless sensor networks (WSNs) refer to networks of spatially dispersed and dedicated sensors that monitor and record the physical conditions of the environment and forward the collected data to a central location. WSNs can measure environmental conditions such as temperature, sound, pollution levels, humidity and wind.

<span class="mw-page-title-main">Teleoperation</span> Operation of a system or machine at a distance

Teleoperation indicates operation of a system or machine at a distance. It is similar in meaning to the phrase "remote control" but is usually encountered in research, academia and technology. It is most commonly associated with robotics and mobile robots but can be applied to a whole range of circumstances in which a device or machine is operated by a person from a distance.

<span class="mw-page-title-main">Unmanned ground vehicle</span> Type of vehicle

An unmanned ground vehicle (UGV) is a vehicle that operates while in contact with the ground and without an onboard human presence. UGVs can be used for many applications where it may be inconvenient, dangerous, or impossible to have a human operator present. Generally, the vehicle will have a set of sensors to observe the environment, and will either autonomously make decisions about its behavior or pass the information to a human operator at a different location who will control the vehicle through teleoperation.

A wireless ad hoc network (WANET) or mobile ad hoc network (MANET) is a decentralized type of wireless network. The network is ad hoc because it does not rely on a pre-existing infrastructure, such as routers or wireless access points. Instead, each node participates in routing by forwarding data for other nodes. The determination of which nodes forward data is made dynamically on the basis of network connectivity and the routing algorithm in use.

<span class="mw-page-title-main">Spherical robot</span>

A spherical robot, also known as spherical mobile robot, or ball-shaped robot is a mobile robot with spherical external shape. A spherical robot is typically made of a spherical shell serving as the body of the robot and an internal driving unit (IDU) that enables the robot to move. Spherical mobile robots typically move by rolling over surfaces. The rolling motion is commonly performed by changing the robot's center of mass, but there exist some other driving mechanisms. In a wider sense, however, the term "spherical robot" may also be referred to a stationary robot with two rotary joints and one prismatic joint which forms a spherical coordinate system.

<span class="mw-page-title-main">Robot navigation</span> Robots ability to navigate

Robot localization denotes the robot's ability to establish its own position and orientation within the frame of reference. Path planning is effectively an extension of localization, in that it requires the determination of the robot's current position and a position of a goal location, both within the same frame of reference or coordinates. Map building can be in the shape of a metric map or any notation describing locations in the robot frame of reference.

Cyber–Physical System (CPS) are integrations of computation with physical processes. In cyber–physical systems, physical and software components are deeply intertwined, able to operate on different spatial and temporal scales, exhibit multiple and distinct behavioral modalities, and interact with each other in ways that change with context. CPS involves transdisciplinary approaches, merging theory of cybernetics, mechatronics, design and process science. The process control is often referred to as embedded systems. In embedded systems, the emphasis tends to be more on the computational elements, and less on an intense link between the computational and physical elements. CPS is also similar to the Internet of Things (IoT), sharing the same basic architecture; nevertheless, CPS presents a higher combination and coordination between physical and computational elements.

<span class="mw-page-title-main">Robotics</span> Design, construction, use, and application of robots

Robotics is the interdisciplinary study and practice of the design, construction, operation, and use of robots.

The Institute of Robotics and Intelligent Systems (IRIS) is part of the ETH Zurich, Switzerland. It replaced the existing Institute of Robotics, of the ETH Zurich in October 2002, when Prof. Bradley J. Nelson moved from the University of Minnesota, United States, to ETH Zurich, and succeeded the Prof. Dr. Gerhard Schweitzer.

<span class="mw-page-title-main">Guardium</span>

Guardium, developed by G-NIUS, is an Israeli unmanned ground vehicle (UGV) used by the Israel Defense Forces along Gaza's border. It was jointly developed by Israel Aerospace Industries and Elbit Industries. It can be used in either tele-operated or autonomous mode. Both modes do not require human interaction. The more unmanned ground vehicles patrolling the area the less human resources needed while guaranteeing deterrence. The joint program was terminated in April 2016, but the vehicle has remained in service with the IDF.

The following outline is provided as an overview of and topical guide to robotics:

<span class="mw-page-title-main">LAURON</span>

LAURON is a six-legged walking robot, which is being developed at the FZI Forschungszentrum Informatik in Germany. The mechanics and the movements of the robot are biologically-inspired, mimicking the stick insect Carausius Morosus. The development of the LAURON walking robot started with basic research in field of six-legged locomotion in the early 1990s and led to the first robot, called LAURON. In the year 1994, this robot was presented to public at the CeBIT in Hanover. This first LAURON generation was, in contrast to the current generation, controlled by an artificial neural network, hence the robot's German name: LAUfROboter Neuronal gesteuert. The current generation LARUON V was finished in 2013.

<span class="mw-page-title-main">National Robotics Engineering Center</span> Operating unit within the Robotics Institute of Carnegie Mellon University

The National Robotics Engineering Center (NREC) is an operating unit within the Robotics Institute (RI) of Carnegie Mellon University. NREC works closely with government and industry clients to apply robotic technologies to real-world processes and products, including unmanned vehicle and platform design, autonomy, sensing and image processing, machine learning, manipulation, and human–robot interaction.

A mobile wireless sensor network (MWSN) can simply be defined as a wireless sensor network (WSN) in which the sensor nodes are mobile. MWSNs are a smaller, emerging field of research in contrast to their well-established predecessor. MWSNs are much more versatile than static sensor networks as they can be deployed in any scenario and cope with rapid topology changes. However, many of their applications are similar, such as environment monitoring or surveillance. Commonly, the nodes consist of a radio transceiver and a microcontroller powered by a battery, as well as some kind of sensor for detecting light, heat, humidity, temperature, etc.

<span class="mw-page-title-main">Workplace robotics safety</span>

Workplace robotics safety is an aspect of occupational safety and health when robots are used in the workplace. This includes traditional industrial robots as well as emerging technologies such as drone aircraft and wearable robotic exoskeletons. Types of accidents include collisions, crushing, and injuries from mechanical parts. Hazard controls include physical barriers, good work practices, and proper maintenance.

<span class="mw-page-title-main">Gyula Mester (robotics)</span> Hungarian scientist (born 1945)

Gyula Mester is a Hungarian scientist and Professor of Robotics at the University of Szeged. He is a member of the Hungarian Academy of Engineering.

References

  1. Hu, J.; Bhowmick, P.; Lanzon, A., "Group Coordinated Control of Networked Mobile Robots with Applications to Object Transportation" IEEE Transactions on Vehicular Technology, 2021.
  2. "Information Engineering Main/Home Page". www.robots.ox.ac.uk. Retrieved 2018-10-03.
  3. 1 2 Hu, J.; Bhowmick, P.; Jang, I.; Arvin, F.; Lanzon, A., "A Decentralized Cluster Formation Containment Framework for Multirobot Systems" IEEE Transactions on Robotics, 2021.
  4. Hu, J.; Turgut, A.; Lennox, B.; Arvin, F., "Robust Formation Coordination of Robot Swarms with Nonlinear Dynamics and Unknown Disturbances: Design and Experiments" IEEE Transactions on Circuits and Systems II: Express Briefs, 2021.
  5. P. Moubarak, P. Ben-Tzvi, Adaptive Manipulation of a Hybrid Mechanism Mobile Robot, IEEE International Symposium on Robotic and Sensors Environments (ROSE), Montreal, Canada, 2011, pp. 113 - 118
  6. Gopalakrishnan, B.; Tirunellayi, S.; Todkar, R. (2014). "Design and development of an autonomous mobile smart vehicle: a mechatronics application". Mechatronics. 14 (5): 491–514. doi:10.1016/j.mechatronics.2003.10.003.
  7. Press release: New Invention Utilizes Empty Railroad Tracks for Shipment of Freight
  8. Linear track (PDF)
  9. "MT400 Build-a-Bot Autonomous Base". mobilerobots.com. Archived from the original on February 23, 2010.
  10. "ias-people". Ias.uwe.ac.uk. Archived from the original on 2008-10-09. Retrieved 2012-08-15.
  11. The world's first truly automatic lawnmover
  12. "Les Earnest". stanford.edu. Retrieved 13 April 2018.
  13. S. Bozinovski, Parallel programming for mobile robot control: Agent based approach, Proc IEEE International Conference on Distributed Computing Systems, p. 202-208, Poznan, 1994
  14. Bozinovski, Stevo (2017). "Signal Processing Robotics Using Signals Generated by a Human Head: From Pioneering Works to EEG-Based Emulation of Digital Circuits". Advances in Robot Design and Intelligent Control. Advances in Intelligent Systems and Computing. Vol. 540. pp. 449–462. doi:10.1007/978-3-319-49058-8_49. ISBN   978-3-319-49057-1.
  15. Proceedings of IEEE Robotics and Automation, 1988
  16. S. Bozinovski, M. Sestakov, L. Bozinovska: Using EEG alpha rhythm to control a mobile robot, In G. Harris, C. Walker (eds.) Proc. Annual Conference of IEEE Medical and Biological Society, p. 1515-1516, New Orleans, 1988
  17. 1 2 S. Bozinovski: Mobile robot trajectory control: From fixed rails to direct bioelectric control, In O. Kaynak (ed.) Proc. IEEE Workshop on Intelligent Motion Control, p/ 63-67, Istanbul, 1990
  18. "Robotics Institute: Dante I". Ri.cmu.edu. Archived from the original on 2007-03-09. Retrieved 2012-08-15.
  19. "Robotics Institute: Dante II". Ri.cmu.edu. Archived from the original on 2008-05-15. Retrieved 2012-08-15.
  20. Welcome to the Swarm-bots web site
  21. N. Bozinovska, Gj. Jovancevski, S. Bozinovski, Internet-based robot control, In Proceedings of the Third International Conference on Informatics and Information Technology, Bitola, Macedonia p.82-89, Dec. 12-15, 2002
  22. "Centibots Project Home Page". Ai.sri.com. 2004-10-04. Retrieved 2012-08-15.
  23. "Archived copy" (PDF). foster-miller.com. Archived from the original (PDF) on December 6, 2006.{{cite web}}: CS1 maint: archived copy as title (link)
  24. Welcome, Archived April 16, 2008, at the Wayback Machine
  25. Speci-Minder
  26. "Archived copy". mobilerobots.com. Archived from the original on September 28, 2007.{{cite web}}: CS1 maint: archived copy as title (link)
  27. Stacey, Olivia (8 July 2016). "Dallas SWAT Used Robot Bomb to Kill Micah X. Johnson in 'First Lethal Use of Robot by Police'". heavy.com. Retrieved 13 April 2018.
  28. Hall, Loura (2016-09-08). "NASA Awards $750K in Sample Return Robot Challenge" . Retrieved 2016-09-21.
  29. "Enhanced Safety Thanks to the ARGOS Challenge". Total Website. Retrieved 13 May 2017.