| In order to improve the anti-roll performance of the vehicle,the active stabilizer bar technology has become a research hotspot.Compared with the drive of BLDCM and hydraulic pump,the active stabilizer driven by switched reluctance motor has the advantages of simple structure,no demagnetization,fast response and good anti stall ability.However,the active stabilizer bar system driven by switched reluctance motor is a electromechanical transmission system which is coupled by mechanical,electromagnetic and electrical control parameters.In view of the multi-parameters coupling characteristics of the system,the nonlinear vibration characteristics of the system under mechanical-electromagnetic coupling,the nonlinear characteristics of power converters under electrical-electromagnetic coupling and the corresponding adaptive control strategies were studied.The main research contents and conclusions were as follows:(1)Design a switched reluctance motor for vehicle active stabilizer bar.By establishing the vehicle roll moment balance equation,the target torque of the switched reluctance motor suitable for the vehicle was calculated.According to the target torque,the rated power of the switched reluctance motor was calculated indirectly,and the corresponding switched reluctance motor was designed based on the empirical method.Finally,the performance of the prototype was verified by finite element analysis and loading experiment.When the motor run at a speed of 1500r/min,the motor can output an average torque of 3Nm,which proved that the designed switched reluctance motor can meet the requirements of the vehicle and output the corresponding anti-roll torque.(2)Modeling of nonlinear flux curves of a switched reluctance motor.The magnetic field is the bridge between mechanical system and electromagnetic system,and the flux linkage model is the basis of analyzing electromechanical coupling characteristics.In order to study the electromechanical coupling characteristics of the electromechanical transmission system of the active stabilizer bar driven by the switched reluctance motor,a CDRNN network with a logistic mapping in the feedback layer was designed.Based on this network,the parameters of the nonlinear exponential flux linkage model of the switched reluctance motor were estimated,and the nonlinear flux linkage analytical model of the switched reluctance motor was obtained.By comparing the flux linkage value calculated by the analytical model with the experimental data,it was found that the error does not exceed 0.015 wb,which verified the effectiveness of the proposed analytical flux linkage model.(3)Analysis of nonlinear vibration characteristics of system under mechanicalelectromagnetic coupling.Based on the Lagrange-Maxwell equation,an electromechanical coupling dynamic model of a switched reluctance motor type active stabilizer bar electromechanical transmission system was established,and the multi-scale method was used to solve it.The main resonance amplitude equation of the system in steady state and the steady stability equation of the system were obtained.Furthermore,the nonlinear characteristic of the system under load excitation was verified by numerical and experimental methods.By calculating the acceleration of the system and its unit frequency spectrum,it was found that the system not only had the vibration of the fundamental frequency component when the load was excited at low frequency,but also had the non integral harmonic component,which indicated that the system will generate the corresponding nonlinear vibration under the low frequency load excitation.(4)Research on electrical electromagnetic coupling characteristics of motor power converter.Considering the influence of the parameters of the control system,the segmentation model of the power converter was obtained based on the boundary characteristics of the current.Based on the fixed point stability theory,the stability of the discrete model of the power converter was quantitatively analyzed under period-1,and the condition of the critical stability point under the coupling of control parameters and electromagnetic parameters was obtained.Numerical and experimental methods were used to study the dynamic characteristics of the switched reluctance motor power converter under the coupling of electrical and electromagnetic parameters.It was concluded that the system’s current power spectrum appeared continuous when the parameters entered a certain area under the coupling of electrical-electromagnetic parameters,indicating that the system had complex nonlinear characteristics.(5)Design and implementation of adaptive control system based on backstepping sliding mode method.Considering the external disturbance of the system,an adaptive backstepping sliding mode controller was designed to improve the anti roll performance of the vehicle,and the simulation of the vehicle under double lane change condition was carried out based on the co simulation platform of CarSim and MATLAB/Simulink.Compared with the passive stabilizer and sliding mode control method,the proposed adaptive backstepping sliding mode control method can effectively reduce the vehicle roll angle under the consideration of uneven road surface.In order to further verify the effectiveness of the control method,the software and hardware of the control system were designed,and a system test bench which can simulate the uneven road excitation was built.The experiment results showed that the roll angle of the vehicle was controlled by the active stabilizer bar driven by switched reluctance motor compared with the passive stabilizer bar under the excitation of uneven road surface,which had verified the effectiveness of the adaptive backstepping sliding mode control method proposed in this paper.From what had been discussed above,an electromechanical coupling dynamic model of an active stabilizer bar electromechanical transmission system driven by a switched reluctance motor was established,and the nonlinear dynamic characteristics under the excitation of related parameters were studied.A vehicle roll adaptive control system based on backstepping sliding mode and a test platform to simulate the excitation of uneven roads were designed.The research work provided a reference for improving the reliability of electromechanical transmission components and the anti-roll performance of vehicles. |
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