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Cyber–physical systems (CPSs) are physical and engineered systems whose operations are monitored, coordinated, controlled, and integrated by a computing and communication core. This intimate coupling between the cyber and physical spheres will be manifested from the nanoworld to large-scale wide-area systems of systems. The Internet transformed how humans interact and communicate with one another, revolutionized how and where information is accessed, and even changed how people buy and sell products. Similarly, CPSs will transform how humans interact with and control the physical world around us. Examples of CPSs include medical devices and systems, aerospace systems, transportation vehicles and intelligent highways, defense systems, robotic systems, process control, factory automation, building and environmental control, and smart spaces. Since a CPS interacts with the physical world, it must operate dependably, safely, securely, efficiently, and in real time. Applications with enormous societal impact and economic benefit will be created by harnessing these capabilities across both space and time.



Some recent technological trends represent a push behind the advent of CPS. Sensors, ranging in size from macroscales to microscales and even nanoscales, are available to measure many aspects of nature such as the state of physical variables, chemicals, fluids, solids, and biological matter. Similarly, actuators abound and vary from battery-operated motors to giant construction equipment. Alternative energy sources and techniques for energy harvesting are multiplying and maturing. Satellite and/or wireless communications are accessible across the globe. Internet connectivity is rapidly growing around the planet. Computing and storage capacities continue to grow near-exponentially and are increasingly available in smaller sizes and form factors. Concurrently, specific demands serve as a pull for the outcomes of sound CPS foundations and workforce. Application domains such as building and environmental control for green practices, critical infrastructure monitoring, process control, factory automation, healthcare, aerospace, and defense are being pressured by customer needs and ongoing competition to develop and deliver CPS capabilities. Driven by these strong pushing and pulling forces, the cyber capabilities of computing and communications will continue to be embedded in handheld gadgets, environmental objects, and the physical infrastructure around us. Physical objects will be addressable and reachable via communications. Endowed with built-in distributed intelligence and the ability to interact with human users, CPSs will enable many milestones to be reached across several sectors of society. We envision the following advances in the coming years and decades.

Fully autonomous vehicles will transport their passengers safely and efficiently to their destinations (Fig. 1). They can then even go pick up the next passengers requesting their services. By enabling mobility, the independence and self-esteem of elderly citizens will be enhanced. Near-zero fatalities and minimal injuries will result from automotive accidents, which claim more than one million lives every year globally. Vehicular networks that allow vehicles to communicate with one another and with the infrastructure will lead to significant reductions in traffic congestion and unexpected traffic delays. Intersections will allow for safe and maximal throughput even without traffic lights. Roads and lanes will be much better utilized by allowing vehicles to travel more closely and safely.

Figure 1
Fig. 1. “Boss”: The autonomous vehicle from Carnegie Mellon University that won the 2007 DARPA Urban Challenge navigating about 60 mi under urban driving conditions, avoiding traffic and obeying traffic rules by using lidars, radars, cameras, a powerful computing base, high-bandwidth communications, and by-wire actuation.

Smart power grids will detect and contain faults eliminating widespread blackouts and brownouts, and be replenished from highly variable renewable and variable energy sources while yielding a reliable source of electricity to end users. Customers will be given (automated) incentives to offload nonessential electrical workloads to times of the day when demand is much lower. The net effect is that the peak loads on a power plant that drive operating costs will be lowered even as average workloads go up (Fig. 2). Healthcare will be revolutionized in multiple ways. Telemedicine will allow remotely located physicians to physically interact, touch, and “feel” patients elsewhere enabling world-class medical access to people in distant and rural regions. Successful telesurgery will be deployed in the battlefield first and then migrate to on-demand emergencies where time is of the essence. Instead of today's operating rooms (OR) where tangled cables serve as tripping hazards and humans in high-pressure situations have to remember to turn off one device when another conflicting device is turned on, operating rooms will become clutter free with the use of wireless communications among interoperable and self-describing medical devices that also understand the interlocking semantics, automatically preventing two or more devices to be working at cross purposes. Handheld devices will access infrastructure servers and databases to vastly expand the realm of diagnostics and its geographical reach. Smart sensor–actuator networks will monitor and assist elderly, disabled, or sick citizens to stay in the home environment much longer before having the need to move to expensive nursing homes.

Figure 2
Fig. 2. Endpoints in a smart grid will monitor and control every electricity consumption point to optimize energy usage and operating costs. In addition, CPSs will similarly enable the monitoring and control of every point of water, fuel/gas, and heating, ventilation, and air-conditioning (HVAC) consumption.

Extreme-yield agriculture will allow finite amounts of arable land to support growing demands on food, by enabling the optimal use of moisture and the minimal use of pesticides and fertilizers. Physical infrastructure will become intelligent with buildings, roads, bridges, and railroads, and runways no longer being passive, becoming active monitors of their own health status, and calling for preventive maintenance before major failures happen. Manufacturing will become highly automated and flexible with today's flexible 3-D printers scaling up for families of products. Cyber–biological systems will allow probes to be implanted to prevent epileptic attacks, treat dynamic heart conditions, help with amnesia, and circumvent many effects of paralysis. Defense and military activities will be transformed with wars becoming largely cyber–physical with human combat becoming largely obsolete and the army with the stronger cyber–physical capabilities winning battles.

Impact on society: Autonomous vehicles will allow passengers and commuters to engage in productive or relaxing activities. Healthcare will become more accessible and more affordable due to widespread access as well as built-in monitoring and prevention techniques. Natural and man-made disasters will lead to much fewer casualties. The productivity of manufacturing will become much higher. Power generation will become more reliable and environmentally friendly. Land will be used to produce more food with fewer resources.

Impact on education: Engineering education in the future will need to be completely revamped to accommodate the needs of ever-burgeoning CPSs (Fig. 3). Instead of the classical but specialized branches of engineering, engineers will be trained in CPS engineering with emphasis on both cyber and physical aspects, with control theory, physical/mechanical properties, and software becoming core subjects. The barriers across disparate domains will begin to break down as biologists work with engineers who work with computer scientists and physicians. The technologies behind telemedicine and telesurgery will mature and become robust first with the massive delivery of tele-education that crosses national and oceanic boundaries.

Figure 3
Fig. 3. Cyber–physical systems represent a confluence of many domains and enable bold new advances.


CPSs are those that exhibit a tight coupling between the dynamics of physical components and a controlling core that comprises computing and communication capabilities. The Internet transformed how humans interact with one another, revolutionized how and where information is accessed, and even changed how products are bought and sold. Similarly, CPSs will transform how humans interact with and control the physical world around us. These CPSs will have embedded and distributed intelligence, operating dependably, securely, safely, and efficiently in real time, while satisfying privacy constraints. Revolutionary advances are anticipated in the domains of healthcare, medical devices and systems, transportation, manufacturing and process control, aerospace and defense, buildings and other physical infrastructure yielding smart physical systems and spaces. Many technical challenges will be overcome in the coming years, resulting in the construction of a science of CPSs and in technological solutions that make deploying CPSs practical, affordable, and reliable.


The author would like to thank many people who helped craft the vision and scope of cyber–physical systems. They include a multitude of researchers and practitioners, as well as thought leaders at the National Science Foundation and other agencies.


The author is with the Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA 15213 USA (e-mail:


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Ragunathan (Raj) Rajkumar

Ragunathan (Raj) Rajkumar

Ragunathan (Raj) Rajkumar (Fellow, IEEE) received the B.E. degree from the University of Madras, Madras, India, in 1984 and the M.S. and Ph.D. degrees from Carnegie Mellon University, Pittsburgh, PA, in 1986 and 1989, respectively.

He is the George Westinghouse Professor of Electrical and Computer Engineering and with the Robotics Institute at Carnegie Mellon University, Pittsburgh, PA. At Carnegie Mellon, he directs the University Transportation Center (UTC) on Technologies for Safe and Efficient Transportation, as well as the Real-Time and Multimedia Systems Laboratory (RTML). He also codirects the General Motors–Carnegie Mellon Vehicular Information Technology Collaborative Research Laboratory (VIT-CRL) as well as the General Motors–Carnegie Mellon Autonomous Driving Collaborative Research Laboratory (AD-CRL). His research interests include all aspects of cyber–physical systems.

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