| Due to the advantages of strong flexibility,high experience and low travel cost,coupled with the continuous construction of recreational vehicle(RV)camping sites in domestic scenic spots,driving a trailer-mounted recreational vehicle(TMRV)to travel has become a new trend.The front and rear vehicles of the TMRV are connected through the ball joint structure,and are more susceptible to external conditions than the self-propelled RV.Therefore,the focus of this paper is to improve the driving stability of the trailer-mounted RV by reasonably controlling the output torque of the electromagnetic brake.Aiming at the safety problem of trailer-mounted RV during driving,In this paper,a braking control strategy is developed for a trailer-mounted recreational vehicle,a brake controller is designed for use with an electromagnetic brake according to the actual requirements,a complete electromagnetic brake control system is formed,and the control performance is tested.The main work is as follows :1.The dynamics model of the trailer-mounted RV was established.Firstly,the basic structure and working principle of the electromagnetic brake installed on the trailer-mounted RV were analysed,and the theoretical model was derived;secondly,the model was constructed in Trucksim using a series of structural parameters of a certain model of trailer-mounted RV provided by the cooperative unit;finally,the accuracy of the dynamics model was verified through the road test of the trailer-mounted RV,which laid the foundation for the subsequent simulation and verification of the control strategy.Finally,the accuracy of the dynamics model was verified through road tests of the RV,which laid the foundation for the subsequent simulation of the control strategy.2.The braking control strategy for trailer-mounted RV was proposed.Firstly,a simulation analysis of the braking instability mechanism of the trailer-mounted RV was carried out,and the correlation between the form of instability and the sequence of axle locking was investigated;secondly,a synchronous braking control strategy was developed based on the national standard regulations on braking coordination,and a differential braking control strategy was developed with the lateral acceleration of the RV as the control target;Finally,the feasibility of the control strategy was verified in a joint Trucksim/Simulink simulation environment.3.The brake controller was designed.Firstly,the components of the brake controller was selected according to the functional requirements;secondly,the hardware circuit with signal acquisition,signal processing,signal output and battery power supply was designed and tested;finally,the brake control strategy was burned into the brake controller prototype through code writing to make it function as expected.4.The controller control performance test was completed.Firstly,the braking control test system of the towed caravan was built using various sensors and measuring instruments;secondly,the low-pass filtering algorithm was used to process the transmitted signals in view of the problem of mixed noise in the transmitted signals;finally,the effectiveness of the braking control strategy and the reliability of the prototype braking controller were verified under single shift line conditions.The experimental analysis shows that the designed braking controller can meet the actual needs of the present stage,and can improve the driving stability of the trailer-mounted RV. |
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