Research On SBW System Of Crossing Variable Wheel Track Spraying Machine

It's well known that crops are planted line by line,whereas the distance between different lines are changed because of different crops,different methods,even if same crops in different planting areas.Therefore,it requires the machinery vehicles must have the ability of adjusting its distance to fit different lines.So,that's also mean that machinery vehicles may have the function of adjusting its wheel,the character of high ground gap,meanwhile it better has the function of four-wheel drive,to improve its driving ability.As a utility technology in the agricultural machinery field,Variable Wheel Track Technology(VWTT)is the key in the agricultural machinery automation process.Now,the wheel-tread of agricultural vehicles in China is normally manually adjustable.In recent years,also appears the technology of adjust wheel-tread using the method of hydraulic cylinder and link mechanism.So,because of all the above reasons,the paper comes up with a crossing variable wheel track spraying machine,which combines the method of adjusting wheel-tread automatically with the function of four-wheel independent steering by wire.Firstly,the paper proposes a spraying machine with the structure of crossing axle variable wheel track chassis.Changing the vehicle's front and rear axle layout from parallel to “X” cross.Establishing the front wheel steering model and the four-wheel steering model of crossing variable wheel track spraying machine based on 2DOF.And modeling the mathematical model of the steering system of spraying machine by using Simulink.Secondly,researching on the SBW system applied to crossing variable wheel track spraying machine.Using the control strategy based on the ideal angle steer ratio for the control of front wheel angle.And analyzing the advantages and disadvantages of two control modes of the ideal angle steer ratio based on the fuzzy control and the steady state yaw-rate,it is concluded that the fuzzy control can better realize the control of the front wheel angle.Using the four-wheel independent steering control strategy for the spraying machine.Through simulation and analysis,the superiority of the four-wheel independent steering is proved.The paper proposes a method of variable track of the crossing variable wheel track spraying machine.Ingeniously realizing the function of the spraying machine variable track by separate controlling four wheels.It is a great breakthrough compared with the existing mechanical track adjustment and hydraulic variable track method.It not only can realize the stepless adjustment of track,but also be flexible and labor saving compared with hydraulic variable track method.It does not need to manually adjust bolt and nut to manually adjust the size of wheel track.Finally,establishing each part's fault tree of crossing variable wheel track spraying machine SBW system.Finding out the minimum cut sets of SBW system.Designing a mechanical fault tolerant mechanism for crossing variable wheel track spraying machine.It provides protection for the safe and stable running of the spraying machine.