St Petersburg University scientists make driving and flight simulators more realistic and robust
Scientists from St Petersburg University, together with their colleagues from the Institute for Problems in Mechanical Engineering of the Russian Academy of Sciences (St Petersburg), have developed a mathematical model with an adaptive digital control system that will make driving and flight simulators more realistic and will reduce risks of failures due to system overloading. The researchers have compared the proposed model with the analogues, used in the simulators that are currently under development by the Russian company Transas. It has been demonstrated that the proposed control system allows for controlling the pneumatic pistons, responsible for the desired motions of the simulator cab, in a wider range of conditions, up to three times faster and one and a half times more accurately.
Simulators are used to train drivers or pilots to properly control a car or aircraft. Such simulators usually have a simulator cab mounted on a Stewart platform, which is often used as a base simulators component for positioning and motion control. A Stewart platform is a type of parallel manipulator that has six legs attached in pairs to three positions on the platform’s base plate, crossing over to three mounting points on a top plate. Each leg pair is controlled by an actuator to change the leg length, thus controlling the orientation of the platform. Such motion can simulate the tilt of an aircraft when manoeuvring or a car when driving on uneven terrain.
The findings of the project, supported by the Russian Science Foundation, are published in the journal Control Engineering Practice.
It is possible to make such training simulators maximally realistic by providing high-precision tracking control and ensuring prompt response of the actuators to the control system commands. Typically, the response time to command signals in the existing devices is not as quick as in a real-world driving car or flying aircraft affected by multiple external factors, including: weather conditions, road surface and many other factors. Additionally, there have been reports on training simulators’ failures and breakdowns due to overloading or the control system malfunctions, which can make them unsafe for human operators.
To address these shortcomings, the researchers from St Petersburg University and the Institute for Problems in Mechanical Engineering of the Russian Academy of Sciences have studied in detail the dynamics of pneumatic actuators for Stewart platforms. The results of the analysis enabled them to determine the motion controller parameters, which are important to take into account when developing adaptive control systems for motion platforms. In particular, the diameter and weight of the pistons, the length of the movable rods in the drives, and the pressure created by different operating loads on the system components. Based on these characteristics, the researchers have developed algorithms to ensure high time response and tracking precision control for the Stewart platform.
‘From the simulator cab, with a human operator in it, a motion command is sent to the platform to generate the supporting motion, such as tilting, when the steering wheel is turned. To be more specific, this motion command is fed to a digital controller — a device connected to pneumatic pistons — that calculates how to change the pressure applied on the pistons to move the platform to its (new) desired coordinates. The proposed mathematical model enables making such calculations by a controller (or a control system) more accurate, faster and less resource-consuming compared to other control methods,’ said Nikolay Kuznetsov, Principal Investigator of the project supported by the Russian Science Foundation, Doctor of Physics and Mathematics, Corresponding Member of the Russian Academy of Sciences, Head of a Leading Scientific School (a Centre of Excellence) of the Russian Federation in the field of mathematics and mechanics, Head of the Department of Applied Cybernetics at St Petersburg University, and Head of the Laboratory of Information and Control Systems at the Institute for Problems in Mechanical Engineering of the Russian Academy of Sciences.
Additionally, the researchers have analysed the dynamics of movements of the truck-driving simulator, which is currently being developed for the largest truck producer in the Russian Federation KAMAZ by the Russian company Transas. The proposed mathematical model was used to correct the detected faults of the control system; in particular, the operating speed and efficiency of the pistons’ response to the input command signals. Also, the researchers have assessed the possibility of occurrence and suppression of hidden oscillations that could lead to accidents during a training session on the simulator. The research results show that with the proposed control algorithm, the control system of the Transas driving simulator responds faster and with higher tracking precision to a variety of human commands. Hence, the simulation of the non-linear behaviour of the vehicle is more realistic.
Earlier, the scientific group of Professor Nikolay Kuznetsov, as part of the development of the theory of hidden oscillations, together with Professor Leon Chua from the University of California, Berkeley, demonstrated experimentally the existence of hidden attractors — points in the basins of attraction in a simple electrical circuit. The research was noted in the report of the Presidium of the Russian Academy of Sciences as one of the major achievements of Russian science in 2022.
St Petersburg University, the oldest university in Russia, was founded on 28 January (8 February) 1724. This is the day when Peter the Great issued a decree establishing the University and the Russian Academy of Sciences. Today, St Petersburg University is an internationally recognised centre for education, research and culture. In 2024, St Petersburg University will celebrate its 300th anniversary.
The plan of events during the celebration of the anniversary of the University was approved at the meeting of the Organising Committee for the celebration of St Petersburg University’s 300th anniversary. The meeting was chaired by Dmitry Chernyshenko, Deputy Prime Minister of the Russian Federation. Among the events are: the naming of a minor planet in honour of St Petersburg University; the issuance of bank cards with a special design; the creation of postage stamps dedicated to the history of the oldest university in Russia; and the branding of the aircraft of the Rossiya Airlines to name just a few. The University has launched a website dedicated to the upcoming holiday. The website contains information about outstanding University staff, students, and alumni; scientific achievements; and details of preparations for the anniversary.
The developed adaptive control system will also improve driving and flight simulators safety, since the proposed mathematical algorithms not only include the parameters affecting the piston motion, but also data on the maximum load the pistons can withstand. This will prevent overloading that could cause failure or even total breakdown of the simulator. In future, the researchers plan to implement, in cooperation with engineers, the proposed mathematical model in existing training simulators to test their development.
The research project was also supported by a grant from the Ministry of Science and Higher Education of the Russian Federation.