| With the progress of society,the booming economy and the improvement of living standards,the way more and more people travel has undergone earth-shaking changes.Many people choose RVs for self-driving trips.Due to the large space and relatively low prices of trailers,people However,the safety issues that follow have also emerged.Compared with the traditional self-propelled touring vehicle,it has more axles and hinged connection in the middle,which is more prone to brake asynchronous and tail-flicking during braking.In the braking process,dangerous conditions such as braking asynchronous and tail-flicking are more likely to occur,which affects the safety of driving.Therefore,it is imperative to control the braking stability of towed motorhomes.First of all,it introduces the development status of the braking stability of trailers at home and abroad.Through analysis and summary of the ideas of experts and scholars on the braking stability of trailers,the brake control ideas are put forward.In order to obtain the required data,Braking experiments were carried out on the towed RV,and the different conditions of the towed RV’s lock-up of each axle were analyzed,the towed RV model was established,and the Carsim model was built in combination with the measured data to simulate and analyze the in-line shifting work.Under the circumstances,the differential braking of the trailer-mounted motorhome can restrain the yaw rate of the yaw motorhome.Then,according to the functional requirements of the trailer brake controller,this article chooses NXP MCU as the main control chip,including the circuit design of the hardware part,including the peripheral circuit of the main control chip,power circuit,brake and throttle acquisition circuit,Current detection circuit,drive circuit and peripheral circuit of the attitude chip provide support for software writing.The software program is written in Codewarrior.In the braking process,the data of the attitude sensor chip is detected in real time,and different voltage values are output to the towed car,so that the coordination of the braking before and after braking reaches the national standard requirements.The time from when the accelerator is turned on to when the brake pedal is depressed is used to judge the urgency of braking,and to control the towed RV with different strategies.In the process of high-speed driving,by detecting the yaw rate of the trailer,the PID algorithm is used to differentially control the trailer,which can suppress the occurrence of unstable conditions such as tail-flicking and folding.Finally,a simulation experiment was carried out on the controller prototype in the laboratory.By simulating the braking deceleration of the trailer-mounted caravan during the braking process,it was shown that with the increase of the braking deceleration,the braking force on the trailer-mounted caravan increased;Secondly,it simulates the yaw rate of the trailer-mounted RV,and verifies that the controller sample can produce differential braking on the left and right wheels to suppress the tail-flick of the trailer. |
