The goal of this paper is to develop an observer-based disturbance rejection electric power steering (EPS) controller to provide steering assistance and improve the driver’s steering feel. For the purpose of control design, a control-oriented model of a vehicle with a column-assist EPS system is developed and verified against a high-fidelity multibody dynamics model of the vehicle. The high-fidelity model is used to mimic vehicle dynamics to study controller performance in realistic driving conditions. Then, a linear quadratic Gaussian approach is used to design an EPS optimal controller, in which a Kalman filter estimates the unmeasured steering system’s states and external disturbance. A new formulation for the linear quadratic regulator objective function is proposed to take advantages of the known information about the system dynamics to attenuate the disturbance and magnify the driver’s torque.
Finally, the EPS controller is applied to the high-fidelity vehicle model in a software-in-the-loop simulation to evaluate its robustness and performance under realistic conditions. The results show that the proposed controller can effectively reduce the disturbance induced in the steering rack, and simultaneously magnify the driver’s steering torque by use of a bi-linear EPS characteristic curve. Then, to show the disturbance rejection properties of this EPS controller, its performance is compared with H2/H∞ and PID control designs using time and frequency domain analysis.
ChenZYangYLChenLH. Study on boosting curve for electric power steering system based on ADAMS. Adv Mater Res2010; 97–101: 3308–3313. DOI:10.4028/AMR.97-101.3308.
2.
ZhouBBeiSYZhaoJB. Computer-aided design of curved assistance characteristic of EPS system. Appl Mech Mater2011; 39: 598–601. DOI:10.4028/AMM.39.598.
3.
ZhaoXShiXChenJ. Dynamic correction of the steering-characteristic curve and application to an EPS control system. Int J Automotive Technol2011; 12(2): 243–249.
4.
LeeMHHaSKChoiJY. Improvement of the steering feel of an electric power steering system by torque map modification. J Mech Sci Technol2005; 19(3): 792–801.
5.
Xue-PingZXinLJieC. Parametric design and application of steering characteristic curve in control for electric power steering. Mechatronics2009; 19(6): 905–911. DOI:10.1016/j.mechatronics.2009.05.003.
6.
MehrabiNMcPheeJ. Steering feel improvement for different driver types using model-based control. In Proceedings of ASME 2014 international design engineering technical conferences and computers and information in engineering conference, Buffalo, NY.
7.
ChabaanRWangL. Control of electrical power assist systems: H∞ design, torque estimation and structural stability. JSAE Rev2001; 22: 435–444.
8.
DaqingTGuofuYGangX. Model and h∞ robust control design for electric power steering system. In Intelligent mechatronics and automation conference, Chengdu, China, pp. 779–783.
9.
ChabaanR. Optimal control and gain scheduling of electrical power steering systems. IEEE vehicle power and propulsion conference, 2009; pp. 53–59. DOI:10.1109/VPPC.2009.5289870.
10.
ChabaanRC. H∞ Control Design and Gain Scheduling of Electrical Power Assist Steering Systems to Improve System Robustness and Stability. PhD Thesis, Wayne State University, Detroit, MI, USA, 2009.
11.
ParmarMHungJY. A sensorless optimal control system for an automotive electric power assist steering system. IEEE Trans Ind Electron2004; 51(2): 290–298.
12.
PeilinSShixiangGLidongM. Optimal controller design for electric power steering system based on lqg. In Information engineering and computer science conference, Wuhan, China, pp. 1–4. DOI:10.1109/ICIECS.2009.5365931.
13.
ChituCLacknerJHornM. Controller design for an electric power steering system based on lqr techniques. COMPEL2013; 32(3): 763–775. DOI:10.1108/03321641311305737.
14.
ZhaoWWangC. Mixed h2/h∞ road feel control of eps based on genetic algorithm. Sci China Technol Sci2012; 55(1): 72–80.
15.
El-shaerAHSugitaSTomizukaM. Fixed-structure controller design of electric power steering systems. In American Control Conference, St. Louis, MO, pp. 445–450.
16.
El-shaerAHTomizukaM. Robust multi-objective control for systems involving human-in-the-loop passivity constraints with application to electric power steering. In 2010 IEEE/ASME international conference on advanced intelligent mechatronics, Montreal, Canada, pp. 361–366. DOI:10.1109/AIM.2010.5695873.
17.
TamuraTMaroonianAFuchsR. Active compensation of friction in electric power steering. In Proceedings of the FISITA 2012 World automotive congress, vol. 198. Berlin: Springer, 2013, pp. 213–225. DOI:10.1007/978-3-642-33795-6.18.
18.
DannöhlCMüllerSUlbrichH. H∞ -control of a rack-assisted electric power steering system. Vehicle Syst Dyn2012; 50(4): 527–544. DOI:10.1080/00423114.2011.603051.
19.
GrollMVMuellerSMeisterT. Disturbance compensation with a torque controllable steering system. Vehicle Syst Dyn2006; 44(4): 327–338. DOI:10.1080/00423110500405242.
20.
LiLHeLDuJ. An electric power steering system controller based on disturbance observer. In IEEE international conference on integration technology, Shenzhen, China, pp. 446–449. DOI:10.1109/ICITECHNOLOGY.2007.4290516.
21.
DongLKandulaPGaoZ. On a robust control system design for an electric power assist steering system. In American control conference, Baltimore, MD, pp. 5356–5361.
22.
MehrabiNMcPheeJL. AzadNL. Optimal disturbance rejection control design for electric power steering systems. In 50th IEEE conference on decision and control and European control conference (CDC-ECC), Orlando, FL, pp. 6584–6589.
23.
LiXZhaoXPChenJ. Sliding mode control for torque ripple reduction of an electric power steering system based on a reference model. Proc IMechE, Part D2008; 222(12): 2283–2290. DOI:10.1243/09544070JAUTO926.
24.
KnapczykJManiowskiM. Stiffness synthesis of a five-rod suspension for given load-displacement characteristics. Proc IMechE, Part D2006; 220(7): 879–889. DOI:10.1243/09544070JAUTO63.
25.
HallAUchidaTLohF. Reduction of a vehicle multibody dynamic model using homotopy optimization. Arch Mech Eng2013; 60(1): 23–35.
26.
HallAMcPheeJ. Automation of ADAMS/car K&C correlation using Matlab. SAE Technical Paper 2014-01-0847. DOI:10.4271/2014-01-0847.
27.
TamuraTMaroonianAHigashiM. Modeling and simulation for dynamic analysis of column type electric power steering. JTEKT Eng J2013; (1010E): 19–25.
28.
ShinMCKimSHChoGH. Development of a steering-system model considering viscous friction and its verification. Proc IMechE, Part D2014; 228(2): 144–163. DOI:10.1177/0954407013506566.
29.
ArmstrongBCanudasDWC. Friction modeling and compensation. In The Control Handbook. Boca Raton, FL: CRC Press, 1996.
30.
WongJY. Theory of Ground Vehicles. New York: John Wiley & Sons, 2001.
FialaE. Seitenkrafte am rollenden luftreifen. VDI Zeitschrift1954; 96(29): 973–979.
33.
KirkDE. Optimal Control Theory - an Introduction. New York: Dover Publications, 2004.
34.
LinCF. Advanced Control System Design. Englewood Cliffs, NJ: Prentice-Hall, Inc., 1994.
35.
SampsonDCebonD. Active roll control of single unit heavy road vehicles. Vehicle Syst Dyn2003; 40(10): 229–270.
36.
ZhaoWShiGLinY. Study on mixed h∞/h2 control for enhancing the tracking performance of EPS. In IEEE international conference on automation and logistics, Jinan, China, pp. 628–633. DOI:10.1109/ICAL.2007.4338640.
37.
ChenXXYangTZhouK. A generic model-based advanced control of electric power-assisted steering systems. IEEE Trans Control Syst Technol2008; 16(6): 1289–1300.
