Robust fractional order event-based control for optimised resource allocation in complex cyber-physical closed loop systems

Research grant awarded by UEFISCDI Romania www.uefiscdi.gov.ro, project code: PN-III-P1-1.1-TE-2016-1396, TE 65/2018

SUMMARY

Wireless sensors and actuators networks (WSAN) are frequently encountered nowadays in various domains that influence the safety, health and comfort of the entire population, this trend being regarded as one of the most critical technologies for building future cyber-physical systems. A key issue in WSAN control loops is that one of the crucial requirements consists in the reduction in the information exchanged between the agents in the control loop (sensors, controllers, actuators) and one of the most convenient strategies is to use event-based sampling and control . Also, time delay variations are frequently encountered in WSAN systems and must be robustly dealt with to avoid instability problems and to maintain desired closed loop performance. By allowing nonperiodic information updates in the control loop, resource allocation can be optimised and power consumption can be minimised. So far, event-based control approaches have been somewhat limited to PID controllers, with very few advanced control algorithms considered such as event-based model predictive control / H∞ robust control. The present project attempts to overcome this limit through the development of modern event-based control approaches, based on one of the newest trends in advanced process control: the fractional order controller. Thus, the main overall objective of the research grant is to develop robust and efficient control algorithms, by combining two novel concepts: event-based control solutions and fractional order control algorithms. The project aims at experimenting, testing and validating this original method, as well as on a novel design of fractional order controllers to robustly manage time delay variations. The major focus of the project is thus directed towards improving general public safety and comfort, by coming up with novel solutions for a robust behaviour of WSAN systems, despite changing environmental conditions, combined with an optimal resource allocation.

OBJECTIVES

The main overall objective of the research grant is to develop robust and efficient control algorithms, by combining two novel concepts: event-based control solutions and fractional calculus (FC). The project aims at experimenting, testing and the validation of original methods to be applied to processes where wired connections are practically impossible (WSAN systems as applications mentioned in Section C1). The major focus of the project is thus directed towards improving safety and comfort, by coming up with novel solutions for a robust behaviour of WSAN closed loop control systems, despite changing environmental conditions, combined with an optimal resource allocation. The specific objectives of the project are as follows: Objective 1: Development of a complete and up- to-date study of the state of the art regarding event-based PID controllers and FO PID control
algorithms for WSAN systems (characterized by variable time delays); Objective 2: Design of novel FO PID controllers for time delay processes based on an extended IMC methodology and an exact discrete-time implementation of resulting fractional order controllers (FOC); Objective 3: Development of event-based FO PID control rules; Objective 4: Highlighting the advantages of event- based FO PID controllers over event-based PID controllers in terms of closed loop robustness, as well as the advantages over standard FO PID controllers in terms of resource allocation.

PROJECT REPORTS

Stage 1 of the project (may-december 2018): three research activities have been scheduled for 2018, referring to a comprehensive study of state of the art regarding fractional calculus in control engineering applications and to a comprehensive study of existing FO PID controllers for time delay processes (WSAN systems). This later study has been concluded with a review paper regarding the most recent. The last research activity completed during this first stage of the project consists in a in depth study and analysis of newest trends in event-based PID control strategies. The fourth activity refers to the dissemination of the results (the resulting papers can be viewed below).

Stage 2 of the project (ongoing): a series of research activities directed towards the development of novel FO-IMC control tuning strategies based on a new approximation method for dead-times. The major focus is directed towards the extension of this design to event based control, using an event based PID algorithm and a fractional order filter, tuned according to the FO-IMC rules as designed above.

OVERALL PROJECT RESULTS

OVERALL SCIENTIFIC RESULTS

2018

  1. Muresan, C.I., Copot, C., Birs, I.R., De Keyser, R., Vanlanduit, S., Ionescu, C. (2018), Experimental validation of a novel auto-tuning method for a fractional order PI controller on an UR10 robot, Algorithms, 11(7), pp. 95, DOI: 10.3390/a11070095 (Emerging List JOURNAL)
  2. Birs, I., Muresan, C.I., Nascu, I., Ionescu, C. (2019), A Survey of Recent Advances in Fractional Order Control for Time Delay Systems, IEEE Access, vol. 7, no. 1, pp. 30951-30965, DOI: 10.1109/ACCESS.2019.2902567 (ISI impact factor 4.098)
  3. Birs, I.R Muresan, C.I., Prodan, O.,Folea, S., (2018), An experimental tuning approach of fractional order controllers in the frequency domain, ESAIM: Control, Optimisation and Calculus of Variations, under review (ISI impact factor 1.225)
  4. Birs, I.R., Muresan, C.I., Prodan, O., Folea, S.C., Ionescu, C.M. (2018), Structural vibration attenuation using a fractional order PD controller designed for a fractional order process, 3rd IFAC Conference on Advances in Proportional-Integral-Derivative Control PID 2018, IFAC-Papers Online, Vol. 51, no. 4, pp. 533-538, DOI: 10.1016/j.ifacol.2018.06.150 (ISI PROCEEDINGS)
  5. Muresan, C.I., De Keyser, R., Birs, I.R., Copot, D., Ionescu, C. (2018) Benchmark Challenge: a robust fractional order control autotuner for the Refrigeration Systems based on Vapor Compression, 3rd IFAC Conference on Advances in Proportional-Integral-Derivative Control PID 2018, IFAC-Papers Online, Vol. 51, no. 4, pp. 31-36, DOI: 10.1016/j.ifacol.2018.06.021 (ISI PROCEEDINGS)
  6. Birs, I.R Muresan, C.I., Folea, S., Prodan, O., Ionescu, C. (2018), Fractional order modeling and control of a carrier prototype for targeted drug delivery, Proceedings of The 2nd International Conference on Industrial Design Engineering (ICIDE 2018), ACM Digital Library, DOI: 10.1145/3290818.3290833, 21-23 September 2018, Phuket, Thailand (ISI PROCEEDINGS)

2019

  1. De Keyser, R., Muresan, C.I., Ionescu, C. (2019), Universal Direct Tuner for Loop Control in Industry, IEEE Access, vol. 7, pp. no. 1, pp. 81308-81320, DOI: 10.1109/ACCESS.2019.2921870 (ISI impact factor 4.098)
  2. Muresan, C.I., Copot, C., Ionescu, C., De Keyser, R. (2019), Robust Fractional Order Control of LPV Dynamic Mechatronic Systems, The 15th IEEE International Conference on Control and Automation (IEEE ICCA 2019), July 16-19, 2019, in Edinburgh, Scotland, accepted
  3. De Keyser, R.,  Muresan, C.I. (2019), Validation of the KC Autotuning Principleon a Multi-Tank Pilot Process, Preprints, 12th IFAC Symposium on Dynamics and Control of Process Systems, including Biosystems, pp. 178-183, Florianópolis – SC, Brazil, April 23-26, 2019
  4. Muresan, C.I., Birs, I., Darab, C., Prodan, O., De Keyser, R. (2019), Alternative Approximation Method for Time Delays in an IMC Scheme, The Aegean Conference on Electrical Machines and Power Electronics and Optimization of Electrical & Electronic Equipment Conference, Istanbul, Turkey, August 27-29 2019, accepted
  5. C. Muresan, I. Birs, R. De Keyser (2019), An Improved Design Approach for Fractional Order Internal Model Controllers for Time Delay Systems, IET Control Theory and Applications, under review ( (ISI impact factor 3.526)
  6. C. I. Muresan, I. R. Birs, O. Prodan, I. Nascu, R. De Keyser (2019), Approximation Methods for FO-IMC Controllers for Time Delay Systems, The 2nd International Conference on Electrical Engineering and Green Energy,  Roma, Italy, June 28-30, 2019, accepted

RESEARCH TEAM

Dr. Eng. Cristina I. Muresan – principal investigator

Dr. Eng. Clara Ionescu

Dr. Eng. Ovidiu Prodan

DR. Eng. Cosmin Darab

Eng. Isabela Birs (PhD student)