Distributed Formation Control Algorithm for Improved String Stability in Heterogenic Vehicle Platoons

Abstract

Achieving speed, safety and energy optimization in vehicle platoons is among the important topics of recent years. In this context, this work focuses on improving the string stability (SS) of heterogeneous platoons. Better SS allows for smaller gap between vehicles, which means shorter time headway for Cooperative Adaptive Cruise Control (CACC) or inter-vehicle following-distance for platooning. Shorter time headway or inter-vehicle distance results in better road use and less fuel consumption. Rather than compensating for dynamic differences by means of low level control schemes by implementing pre-compensators at vehicle level, this work takes a different approach, where a higher level of control is preferred to improve SS: The platoon formation. To achieve this, it is important to ensure that each vehicle is in its optimum position in the platoon based on its dynamics for highest string stability. This generally leads to the vehicle with highest inertia to lead the platoon and the lowest one as the last follower. In this study, a platoon formation algorithm is proposed to run on each vehicle, leading to an optimum overall string structure. The efficiency of the algorithm is demonstrated by simulations in Matlab(R) for a four-vehicle platoon.

Keywords

• Cruise control
• distributed formation
• heterogenic vehicle platoon
• string stability

References

1. [1] S. Fenga , Y. Zhanga , S. E. Li, Z. Cao, H. X. Liuc, L. Li. “String stability for vehicular platoon control: Definitions and analysis methods”. Annual Reviews in Control, 47, pp 81-97, 2019.
2. [2] Y.A. Harfouch, S. Yuan, S. Baldi. “Adaptive Control of Interconnected Networked Systems with Application to Heterogeneous Platooning”. 2017 13th IEEE International Conference on Control and Automation (ICCA) July 3-6, 2017. Ohrid, Macedonia.
3. [3] M. Sun, F.L. Lewis, S.S. Ge. “Platoon-Stable Adaptive Controller Design”. 43rd IEEE Conference on Decision and Control December 14-17, 2004 Atlantis, Paradise Island, Bahamas.
4. [4] J. Ploeg, D.P. Shukla, N. Wouw, H. Nijmeijer. “Controller Synthesis for String Stability of Vehicle Platoons”. IEEE Transactions On Intelligent Transportation Systems, Vol. 15, N. 2, April 2014.
5. [5] X. Guo, J. Wang, F. Liao, R.S.H. Teo. “Distributed Adaptive Integrated-Sliding-Mode Controller Synthesis for String Stability of Vehicle Platoons”. IEEE Transactions On Intelligent Transportation Systems, VOL. 17, NO. 9, September 2016.
6. [6] F. Li, Y. Wang. “Cooperative Adaptive Cruise Control for String Stable Mixed Traffic: Benchmark and Human-Centered Design”. IEEE Transactions On Intelligent Transportation Systems, VOL. 18, NO. 12, December 2017.
7. [7] S.E. Li, R. Li, J. Wang, X. Hu, B. Cheng, K. Li. “Stabilizing Periodic Control of Automated Vehicle Platoon with Minimized Fuel Consumption”. IEEE Transactions On Transportation Electrification, Vol. 3, No. 1, March 2017.
8. [8] L. Zuo, Y. Zhang, M. Yan, W. Ma. “Distributed Integrated Sliding Mode-Based Nonlinear Vehicle Platoon Control with Quadratic Spacing Policy”, Complexity, 2020.

9. [9] H. Zheng, J. Wu, W. Wu, R. R. Negenborn. “Cooperative distributed predictive control for collision-free vehicle platoons”. IET Intelligent Transport Systems, Volume 13, Issue 5, 2018.
10. [10] K. Massow, I. Radusch, R. Shorten. “On Constant Distance Spacing Policies for Cooperative Adaptive Cruise Control”. arXiv:1909.10913v2, Cornell University, 2020.
11. [11] J. Ploeg, N. van de Wouw, H. Nijmeijer. “String Stability of Vehicle Platoons”. Book of Abstracts of the 30Th Benelux Meeting On Systems and Control, 2014.
12. [12] J. Eyre, D. Yanakiev, I.A. Kanellakopoulos. “Simplified Framework for String Stability Analysis of Automated Vehicles”. Journal of Vehicle System Dynamics, 30:5, 375-405, 1998.
13. [13] S.S. Stankovic, M.J. Stanojevic, D.D. Siljak. “Decentralized Overlapping Control of a Platoon of Vehicles”. IEEE Transactions On Control Systems Technology, Vol.8, No.5, 2000.
14. [14] J. Ploeg, N. Wouw, H. Nijmeijer. “Lp String Stability of Cascaded Systems”. IEEE Transactions On Control Systems Technology, Vol. 22, No. 2, March 2014.