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Control theory in a selfish world

From self-driving cars, smart traffic lights to energy systems balancing supply and demand: the future is filled with autonomous systems. But what happens if autonomous systems are put together and need to work together? Sergio Grammatico aims to deal with non-cooperative agents such as human-driven cars among autonomous vehicles. The next frontier in autonomous systems Sergio Grammatico, assistant professor at the Delft Center for Systems and Control, is already thinking about the next step: bringing multiple autonomous systems together in a ‘system of systems’ - for example, a highway full of self-coordinating, self-driving cars. Based on the mathematical principles of control theory, robots and vehicles have been taught to function autonomously for decades. Grammatico: “Thanks to today’s computational capabilities, we now have local intelligent systems that can fully operate by themselves.” This coordination among autonomous ‘agents’ is what Grammatico calls the next frontier. Multi-agent control “Think of modern traffic control. Individual traffic lights are programmed such that they can do a great job within the local surrounding of an intersection. But if you think in the context of a larger area such as an entire city, then it would be much more helpful if there is coordination among traffic lights.” This is where multi-agent control theory comes into the picture. Another example: modern power grids. “There used to be a single control system managing the power flow from generators to consumers. Nowadays, energy production, storage and consumption take place everywhere, for example in the photovoltaic panels on our roofs. Multi-agent control is essential to make all these individual systems work together in a smart power grid.” Selfish agents Why is the coordination among multiple intelligent systems so difficult? One of the reasons is that not all participating systems have the same interest in contributing to the collective benefit. Some may prefer individual benefits. “We do this every day without noticing it. While driving our car, we just want to arrive at our destination, and care little about the other cars sharing the highway with us. Every energy company making use of the power grid just wants to maximize its own revenues. In mathematical terms, these selfish participants are called non-cooperative. How can we get drivers who are willing to hand over control of their vehicle to the control system, and drivers who do not want to, to work together? What incentives or control signals would make them coordinate their behaviour? Studying populations of cooperative and non-cooperative agents is very important if we want to develop applications in realistic situations. That’s what my ERC project is about.” Game theory While the dynamics are very complex for just one autonomous vehicle, they become even more complex when multiple vehicles interact. Grammatico is adamant that dynamic game theory will provide the keys to solving these coordination problems. “Game theory helps us mathematically model the interests and behaviour of non-cooperative agents. I will use another branch of mathematics – operator theory – combined with distributed control to exploit game models and develop mechanisms to control non-cooperative agents. These tools are already being used in other branches of mathematics, but the approach itself is completely new within the systems and control community.” The most challenging part, Grammatico explains, will be to combine continuous variables and logic/discrete variables. “In autonomous driving, we are not just dealing with continuous variables, such as velocity and acceleration. Important parameters, such as the car’s direction indicators which can be on or off, or the lane the car is driving in, are discrete variables. It will be a huge achievement if we will be able to control such multi-agent hybrid (namely, continuous/discrete) systems. It will open up a completely new research area!” I have always been fascinated by the interplay of engineering and mathematical theories. Engineering and Mathematics come together in multi-agent control theory, indeed. Sergio Grammatico Experimental tests Grammatico will use the ERC funds to set up a framework, a theoretical background, for other researchers to build upon and to generate software that can be immediately be embedded in practical platforms such a robots and autonomous cars. “I have a number of applications in mind for which I want to use the new theory to derive control algorithms, implement them and validate them in practice.” After full-scale numerical simulations, the first experimental tests will be done using eight miniature robotic cars. “If this is successful, we can take the next step and test our algorithms in real-life scenarios on the TU Delft campus, as part of the Green Village living lab programme.” Technology and mathematics Grammatico studied both Engineering Science and Automatic Control Engineering at the University of Pisa. “I have always been fascinated by the interplay of engineering applications and mathematical theories. Engineering and the power of mathematics come together in multi-agent control theory.” In 2017, he moved to Delft University of Technology where he set up his own group funded by Netherlands Organization for Scientific Research (NWO) and now also by the European Research Council (ERC). “Delft is a great place to carry out this kind of research because it has very strong tradition in the field of systems and control. The university has smart people in related disciplines, such as applied mathematics and electrical engineering, and also in different application domains.” Mobility and energy What developments does Grammatico see at the horizon? “I think the full electrification of our cars will take place sooner or later. When all cars are electric, the fields of mobility and energy will come together. We will no longer be able to differentiate between power systems and mobility systems – they will simply merge. I see this as the next engineering challenge for our society. My ERC project will provide the tools to start studying those integrated energy/mobility challenges.” Sergio Grammatico +31 15 27 83593 S.Grammatico@tudelft.nl Academic website This is a story from ME The next frontier in autonomous systems Sergio Grammatico, assistant professor at the Delft Center for Systems and Control, is already thinking about the next step: bringing multiple autonomous systems together in a ‘system of systems’ - for example, a highway full of self-coordinating, self-driving cars. Based on the mathematical principles of control theory, robots and vehicles have been taught to function autonomously for decades. Grammatico: “Thanks to today’s computational capabilities, we now have local intelligent systems that can fully operate by themselves.” This coordination among autonomous ‘agents’ is what Grammatico calls the next frontier. Multi-agent control “Think of modern traffic control. Individual traffic lights are programmed such that they can do a great job within the local surrounding of an intersection. But if you think in the context of a larger area such as an entire city, then it would be much more helpful if there is coordination among traffic lights.” This is where multi-agent control theory comes into the picture. Another example: modern power grids. “There used to be a single control system managing the power flow from generators to consumers. Nowadays, energy production, storage and consumption take place everywhere, for example in the photovoltaic panels on our roofs. Multi-agent control is essential to make all these individual systems work together in a smart power grid.” Selfish agents Why is the coordination among multiple intelligent systems so difficult? One of the reasons is that not all participating systems have the same interest in contributing to the collective benefit. Some may prefer individual benefits. “We do this every day without noticing it. While driving our car, we just want to arrive at our destination, and care little about the other cars sharing the highway with us. Every energy company making use of the power grid just wants to maximize its own revenues. In mathematical terms, these selfish participants are called non-cooperative. How can we get drivers who are willing to hand over control of their vehicle to the control system, and drivers who do not want to, to work together? What incentives or control signals would make them coordinate their behaviour? Studying populations of cooperative and non-cooperative agents is very important if we want to develop applications in realistic situations. That’s what my ERC project is about.” Game theory While the dynamics are very complex for just one autonomous vehicle, they become even more complex when multiple vehicles interact. Grammatico is adamant that dynamic game theory will provide the keys to solving these coordination problems. “Game theory helps us mathematically model the interests and behaviour of non-cooperative agents. I will use another branch of mathematics – operator theory – combined with distributed control to exploit game models and develop mechanisms to control non-cooperative agents. These tools are already being used in other branches of mathematics, but the approach itself is completely new within the systems and control community.” The most challenging part, Grammatico explains, will be to combine continuous variables and logic/discrete variables. “In autonomous driving, we are not just dealing with continuous variables, such as velocity and acceleration. Important parameters, such as the car’s direction indicators which can be on or off, or the lane the car is driving in, are discrete variables. It will be a huge achievement if we will be able to control such multi-agent hybrid (namely, continuous/discrete) systems. It will open up a completely new research area!” I have always been fascinated by the interplay of engineering and mathematical theories. Engineering and Mathematics come together in multi-agent control theory, indeed. Sergio Grammatico Experimental tests Grammatico will use the ERC funds to set up a framework, a theoretical background, for other researchers to build upon and to generate software that can be immediately be embedded in practical platforms such a robots and autonomous cars. “I have a number of applications in mind for which I want to use the new theory to derive control algorithms, implement them and validate them in practice.” After full-scale numerical simulations, the first experimental tests will be done using eight miniature robotic cars. “If this is successful, we can take the next step and test our algorithms in real-life scenarios on the TU Delft campus, as part of the Green Village living lab programme.” Technology and mathematics Grammatico studied both Engineering Science and Automatic Control Engineering at the University of Pisa. “I have always been fascinated by the interplay of engineering applications and mathematical theories. Engineering and the power of mathematics come together in multi-agent control theory.” In 2017, he moved to Delft University of Technology where he set up his own group funded by Netherlands Organization for Scientific Research (NWO) and now also by the European Research Council (ERC). “Delft is a great place to carry out this kind of research because it has very strong tradition in the field of systems and control. The university has smart people in related disciplines, such as applied mathematics and electrical engineering, and also in different application domains.” Mobility and energy What developments does Grammatico see at the horizon? “I think the full electrification of our cars will take place sooner or later. When all cars are electric, the fields of mobility and energy will come together. We will no longer be able to differentiate between power systems and mobility systems – they will simply merge. I see this as the next engineering challenge for our society. My ERC project will provide the tools to start studying those integrated energy/mobility challenges.” Sergio Grammatico +31 15 27 83593 S.Grammatico@tudelft.nl Academic website This is a story from ME Related stories The responsibility gap with self driving cars The impact of algorithms Roboats in Amsterdam

Surgery for all

We’ve all been there. You have had an accident, perhaps bruised or broken a limb and off you go to the accident and emergency department at the hospital. In Africa things are not quite as straightforward. Worldwide a lack of access to basic healthcare kills more people than malaria, HIV/aids and tuberculosis put together. That is why TU Delft professor Jenny Dankelman is all about developing safe and affordable surgical instruments. ‘85% of all 15 year-olds who needed a minor or more important surgical intervention at one point did not get it. Treatment, if available at all, is often at a couple of days travel. Often that is simply too long and patients are left with impairments varying from minor to life-changing, or even die,’ Dankelman says. Complex surgical instruments One of the most complex surgical instruments is an electrosurgical device used to make incisions and cauterise wounds. After cutting, blood loss is kept to a minimum by cauterising the wound as quickly as possible. “Even for highly trained doctors it’s not the easiest of instruments. It has different settings for cutting and cauterising. Research shows that surgeons don’t always know exactly what the different settings mean. As a result, the device is sometimes used inappropriately and that can have serious consequences.’ These devices also find their way to hospitals in developing countries. Focus on the device Clinical surgery departments have been involved in numerous efforts to raise funds for training local surgeons. ‘The focus is on the person who is using the device. But instead of trying to change the user I would rather simplify the device. That is how my group works: we try to find simple solutions. Moreover, apart from use, maintenance, the replacement of parts and an unstable electricity supply can also be a problem in hospitals in countries such as Kenya and India. These are all issues which need to be looked at when developing an instrument.’ Robot technology is a hot topic in Dankelman’s field of expertise. “That kind of technology is not always the best way forward, especially if you want to keep things affordable and simple. If you want to make an impact in countries where healthcare budgets are limited that is where your priority should lie.’ A growing programme and local collaboration Four years ago, Dankelman was a pioneer in the field. Now, 3 PhDs, 2 postdocs and 25 students have joined her on the ‘surgery for all’ project, developing a variety of instruments. ‘We have created a basis for an electrosurgical device and learned much about ways in which 3D printing might be useful in, for instance Kenia. Dankelman always considered local collaboration to be essential. “We have learned so much from the local doctors and staff at the technical support centres of hospitals in Kenia, Nepal and Surinam. And I continue to learn new things every day.’ With biomedical engineering experts from Kenyatta University, Dankelman is studying the context in which surgical instruments are being used. PhD Roos Oosting and industrial design PhD J. C. Diehl joined forces to explore the situation at various local hospitals. ‘Master students have already charted the journey medical instruments make in a local hospital. That gives us such a lot of input on wear and tear and the things the design should take into account,’ Oosting says. Minimally invasive surgery As professor of Minimally Invasive Surgery and Intervention Techniques Dankelman knows all there is to know about operating through small holes, or ‘keyhole surgery’ as it is popularly known. Using smart instruments, needles and flexible catheters, incision size can be brought back considerably, keeping the risk of infection to a minimum. Dankelman’s dream is to start several projects around the improvement of surgical instruments for developing countries. ‘My colleague Tim Horeman is already working on instrument and operating room sterility issues. Ultimately I would like to take the step from open surgery to minimally invasive surgery.” Jenny Dankelman +31 15 27 85565 J.Dankelman@tudelft.nl For more information: TU Delft | Global Initiative ‘85% of all 15 year-olds who needed a minor or more important surgical intervention at one point did not get it. Treatment, if available at all, is often at a couple of days travel. Often that is simply too long and patients are left with impairments varying from minor to life-changing, or even die,’ Dankelman says. Complex surgical instruments One of the most complex surgical instruments is an electrosurgical device used to make incisions and cauterise wounds. After cutting, blood loss is kept to a minimum by cauterising the wound as quickly as possible. “Even for highly trained doctors it’s not the easiest of instruments. It has different settings for cutting and cauterising. Research shows that surgeons don’t always know exactly what the different settings mean. As a result, the device is sometimes used inappropriately and that can have serious consequences.’ These devices also find their way to hospitals in developing countries. Focus on the device Clinical surgery departments have been involved in numerous efforts to raise funds for training local surgeons. ‘The focus is on the person who is using the device. But instead of trying to change the user I would rather simplify the device. That is how my group works: we try to find simple solutions. Moreover, apart from use, maintenance, the replacement of parts and an unstable electricity supply can also be a problem in hospitals in countries such as Kenya and India. These are all issues which need to be looked at when developing an instrument.’ Robot technology is a hot topic in Dankelman’s field of expertise. “That kind of technology is not always the best way forward, especially if you want to keep things affordable and simple. If you want to make an impact in countries where healthcare budgets are limited that is where your priority should lie.’ A growing programme and local collaboration Four years ago, Dankelman was a pioneer in the field. Now, 3 PhDs, 2 postdocs and 25 students have joined her on the ‘surgery for all’ project, developing a variety of instruments. ‘We have created a basis for an electrosurgical device and learned much about ways in which 3D printing might be useful in, for instance Kenia. Dankelman always considered local collaboration to be essential. “We have learned so much from the local doctors and staff at the technical support centres of hospitals in Kenia, Nepal and Surinam. And I continue to learn new things every day.’ With biomedical engineering experts from Kenyatta University, Dankelman is studying the context in which surgical instruments are being used. PhD Roos Oosting and industrial design PhD J. C. Diehl joined forces to explore the situation at various local hospitals. ‘Master students have already charted the journey medical instruments make in a local hospital. That gives us such a lot of input on wear and tear and the things the design should take into account,’ Oosting says. Minimally invasive surgery As professor of Minimally Invasive Surgery and Intervention Techniques Dankelman knows all there is to know about operating through small holes, or ‘keyhole surgery’ as it is popularly known. Using smart instruments, needles and flexible catheters, incision size can be brought back considerably, keeping the risk of infection to a minimum. Dankelman’s dream is to start several projects around the improvement of surgical instruments for developing countries. ‘My colleague Tim Horeman is already working on instrument and operating room sterility issues. Ultimately I would like to take the step from open surgery to minimally invasive surgery.” Jenny Dankelman +31 15 27 85565 J.Dankelman@tudelft.nl For more information: TU Delft | Global Initiative Related stories Affordable MRI Bacteriophages as a possible alternative to antibiotics A beautiful alarm besides your hospital bed

Added value of Clinical Technology proven in practice

From the 3D printing of pills to a device that enables people without vocal cords to speak: the final bachelor projects by students in Clinical Technology demonstrate that technology is changing medical care as drastically as it is transforming our daily lives.

Control theory in a selfish world

From self-driving cars, smart traffic lights to energy systems balancing supply and demand: the future is filled with autonomous systems, programmed to sense their environment and make decisions to reach their goals. Sergio Grammatico, professor at the Delft Center for Systems and Control, is already thinking about the next step: bringing multiple autonomous systems together in a ‘system of systems’ - for example, a highway full of self-coordinating, self-driving cars.

Surgical tool inspired by parasitoid wasp

Surgeons will find it easier to operate with a flexible, ultra-thin and steerable needle. Indeed, many medical applications have a need for this new type of needle, for example during deep medical interventions in the spinal cord. Paul Breedveld, professor of Medical Instruments & Bio-Inspired Technology developed an ultra-thin, flexible and steerable needle with PhD student Marta Scali and fellow researcher Dimitra Dodou.

Gas turbines: essential for the transition to renewable energy sources

Gas turbines are best known as the jet engines that power aircraft. But they also are the work horses of large power plants generating electricity for our industry and homes. At TU Delft, at both the Faculty of Aerospace Engineering (AE) and the Faculty of Mechanical, Maritime and Materials Engineering (3mE), researchers work on this topic.

Hydrogen as the key to a sustainable shipping sector

Sustainability targets for the transport sector are not limited to only road transport. The shipping industry has decided to explore that issue now too. And though CO2 emissions per transported container could be worse, ships are undeniably a considerable source of unwanted emissions, from NOx to particulate matter. TU Delft researcher and former marine officer Klaas Visser believes there are excellent opportunities to change this.