| Vibration is a key factor affecting the performance of the vehicle,which should be damped by the suspension system.The electromagnetic active suspension with linear motor has significant advantages over other active suspensions: its structure is simple and can get a high-quality vibration isolation system in theory;besides,the linear motor can convert the vibration energy of the vehicle into electric energy when working as generator according to the principle of electromagnetic induction,which can overcome the disadvantage of high energy consumption of active suspensions.Main points of this paper included: established a mathematical model of linear motor’s pushing force based on vector control;designed an electromagnetic active suspension controller based on the quarter car system;simulated and analyzed the vibration reduction performance and energy consumption characteristics of the electromagnetic active suspension;analyzed the affecting factors of the performance of electromagnetic active suspension;Finally,analyzed the influence of electromagnetic active suspension on vehicle ride comfort and energy consumption by Carsim-Simulink joint simulation.The main contents and conclusions of this paper are as follows:(1)Completed the coordinate transformation of the linear motor model form a-b-c coordinate to d-q coordinate and deduced the electromagnetic force expression of linear motor in d-q coordinate,which lays the foundation for the follow-up research.(2)An electromagnetic active suspension controller is designed for the quarter car system,including optimal controller and the energy recovery controller.There are four working modes of this electromagnetic suspension,of which the ride comfort,energy recovery and consumption effects in different modes are analyzed by simulation.The results showed that,when targeting energy recovery,the ability of improving ride of electromagnetic suspension can be improved by 359.6% in half energy recovery and energy recovery preferentially mode compared with that in complete energy recovery mode with only 3.5% increase of energy consumption;when targeting ride improvement,the effects of both half energy recovery and improving ride preferentially mode and complete energy consumption mode were almost the same,while half energy recovery and improving ride preferentially mode consumed 19% less energy.(3)The influence of the parameters of the suspension system and the output characteristics of the linear motor on the performance of the electromagnetic suspension is studied based on the quarter car system.The results showed that,when considering the output characteristics,vibration reduction effect and energy consumption characteristics of electromagnetic suspension,the smaller spring stiffness and tire stiffness are within a certain range,the better;If the electromagnetic force output from the linear motor can not meet the optimal active control force demand,the performance of the electromagnetic suspension will decline,and there is a sharp tendency of deterioration.Besides,the importance and effectiveness of matching the elastic characteristics with the output characteristics of a linear motor was validated when designing an electromagnetic suspension.(4)The optimal controller is designed for seven degree of freedom vehicle model.The influence of electromagnetic active suspension on ride comfort control effect and energy consumption characteristics in different modes is analyzed by Carsim-Simulink joint simulation.The results show that,when targeting energy recovery,the electromagnetic suspension can greatly improve the ride in the premise of additional energy consumption in half energy recovery and energy recovery preferentially mode compared with complete energy recovery mode;when targeting ride improvement,half energy recovery and improving ride preferentially mode could achieve the same ride effect with less energy consumed compared with complete energy consumption mode. |
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