Be based on MSC.ADAMS some MPV to operate stability improves an analysis

Of 1 overview car operate stability and all through the ages are a very serious problem in car function, it not just token car drives operate those who take is convenient degree, comfortable, it is a when decide speedster safety travel main function more. As contemporary car speed of a motor vehicle rise, operate to the car the demand of stability is higher and higher also. Be opposite by traditional method of new car operate when stable character undertakes study, need passes design, test, the experiment sums up the problem that come out to feedback to design, the design passes computation, after changing, retrial, the way that this kind of complete support has experimenting achieving adjustment car function to the car after model car trial-produce cannot have satisfied the requirement of development speed and development quality, be necessary to use fictitious experiment technology to undertake forecasting to the function of the car in the design so, undertake in order to be before trial-produce of real model car forecasting to its function, put forward to improve an opinion, achieve raise design quality and the goal that accelerate design rate, the overall level that this designs to raising our country car also is having important sense. Because some MPV is used at special aim, after quality of reorganize and outfit increases 1650Kg by original 1260Kg, its operate stability need undertakes assessment afresh. Forecast its to be before model car trial-produce kinetic character, we use MSC.

ADAMS software is truckload to MPV undertook fictitious emulation analysis, undertake evaluating to the result of the design in notional design phase, find out the inadequacy that exists in the design, put forward to improve plan. 2 truckload of kinetic emulation model build a basis to design need, defined needs fictitious model car according to this MPV parameter, built the model of each subsystem respectively: System of this car front suspension is suspension of independence of Mai Fuxun type, head transverse and stable staff; Rear overhang wearing becomes independent partly to turn round Liang Shi type suspension; Change a system to gear rack type; Tire form is 195R14. To simplify the model takes no account of engine and transmission system, and before be being decided suppose, rear overhang wearing all is or so semmetry. Emulate precision to rise, will hind the CAD model that turns round bridge is in finite yuan undertake reseau differentiates in software, guide through MNF neuter file in ADAMS software, such is in truckload what bridge turns round after considering in kinetic analysis is flexible, make emulate more adjacent and true condition. After had built each subsystem models, what be combined finally and become is truckload kinetic model is shown 1 times like the graph. Graph 1 MPV is kinetic emulation model 3 truckload operate GB6323 of stability emulation GB.

6 regulations of 1 ～ inspect a car to operate stability the experiment of each function index, corresponding our set different emulation operating mode will inspect MPV operate each stable character, length of be confined to, here introduces stable state to turn to characteristic emulation experiment and slalom test only. 3.

Circumgyrate of 1 stable state emulates the stable state of the car to turn to character is the car operates the it is the most important to be mixed the most basically facet in stability, decided the car is in as a kinetic system the sufficient condition that turns to an input to fall to whether be stabilized, in QC/T 480-1999, the car operates stability index is restricted in value and assessment technique, make clear a regulation: The car that stable state circumgyrate fails, its operate the total assessment of stability is fail. 3.

1.

Circumgyrate of 1 stable state emulates imitate to be in the operating mode set of emulation experiment, fictitious emulation test is strict according to GB/T 6323.

6, function of circumgyrate of 94 imitate stable state experiments, test program undertakes along following contrail: Stability starts, the circumferential travel that is 15m along radius, fixed change direction dish do not move slowly successive and even ground to quicken (fore-and-aft acceleration does not exceed 0.

25m/s2) ¬ , till the side direction acceleration of the car is achieved 6.

5m/s2 (or the car appears not steady state) till. To improve numeric calculative stability, fictitious emulate after beginning, initiative speed is set car 0.

5m/s, inside 1s steering wheel turns to book the position, assure to turn radius is 15m, secure steering wheel corner next, and be inside 5s time maintain divide evenly till fast travel emulates an end, travel of contrail of motion of car of fictitious model of the MPV in whole emulation process is shown 2 times like the graph. Circumgyrate of stable state of graph 2 MPV emulates orbit 3.

1.

Evaluation of emulation result of circumgyrate of 2 stable state is emulated after finishing, side of the rear axle before acquisition car slants 2 of δ of 1 - of δ of horny poor cost, Φ of horn of automobile body list and curve of relation of acceleration Ay of automobile body side direction are like a graph respectively 5, graph place of part of 6 dotted line is shown. At the same time the inadequacy of knowable car turns to degree of U = 0.

05(° / (M/s2)) , automobile body list spends K Φ = 0.

97/(m/s2)) , according to the plan cent method of QC/T-480, the list of this car spends the plan cent value of K Φ to be 82 minutes, and the floor level that inadequacy turns to degree of U to did not reach plan cent, namely plan cent value is zero, the inadequacy that demonstrates this car changes characteristic unqualified GB to the requirement [6] , must undertake improvement. 3.

Emulation slalom test of 2 slalom test belongs to a driver - car - the performance of closed circuit system that outside ambient is combined and becomes experiments, this experiment method can reflect a capacity that here car of closed circuit system has changing direction quickly, can mirror instead at the same time the comfortable sex of the member that multiply below this operating mode and security. Slalom test emulates fictitious model car the definition of operating mode consults GB/T6323.

1, through using classical driver beforehand the athletic contrail that draw model controls fictitious model car, emulate car of fictitious model of the MPV after finishing to if the graph is shown 3 times,run orbit. If time process of angular velocity of yaw of place of centroid of automobile body of emulation experiment of move with the body on the ground of contrail of motion of emulation experiment of move with the body on the ground of graph 3 MPV pursues place of part of 7 dotted line is shown, computation reachs its are average angular velocity of the biggest yaw occupies GB its plan cent value is 81 minutes, the slalom test that makes clear MPV car accords with GB requirement. 3.

3 hold firm improve because the stable state of MPV turns to character,reach an analysis unqualified, because this must take step,undertake improvement. Because decorate configuration truckloadly to cannot be changed, because this basically passes tone to rectify truckload and mechanical parameter, be like the diameter of suspension bedspring stiffness and transverse and stable lever, will improve operate certain property. In emulate through many rounds after debugging, will before, stiffness of bedspring of rear overhang wearing increases 28N/mm respectively by original 22N/mm, 20N/mm, 26N/mm, transverse and stable shank diameter increases 28mm by 22mm, if the graph is shown 4 times,right now MPV emulates athletic contrail, side of car around axis slants 2 of δ of 1- of δ of horny poor cost, Φ of horn of automobile body list and curve of relation of acceleration Ay of automobile body side direction are like a graph respectively 5, the graph is shown 6 times () of solid line part. Graph contrail of emulation motion of stable state of the MPV after 4 bedspring stiffness increases pursues before 5 stiffness increase, hind around axis side slants before 6 stiffness increase graph of horny difference and relation of side direction acceleration, after around axis side slants curve of horny difference and relation of side direction acceleration, the inadequacy of the car after stiffness increases turns to degree of U = 0.

3(° / (M/s2)) , automobile body list spends K Φ = 0.

7 (° / (M/s2)) , the inadequacy of corresponding QC/T-480 car change the plan cent value of degree of U to 94 minutes, and the side of plan cent value that list spends K Φ was achieved for 100 minutes, because this can say, after increasing suspension bedspring stiffness, the character of stable state circumgyrate of the car is improved apparent, if pursue,at the same time centroid of automobile body of emulation experiment of move with the body on the ground manages time process of yaw angular velocity place of part of 7 solid line is shown, get angular velocity of average the biggest yaw right now γ M=15(° / S) , according to GB plan cent value is 87 minutes, the slalom test expression of the MPV after showing suspension stiffness increases is much better. 4 truckload after ride comfort emulates advanced rear overhang to wear bedspring stiffness to increase, its smooth-going function will naturally be affected, before because this need passes comparative analysis,suspension stiffness is changed, hind truckload smooth-going character comes the ride comfort of desired result MPV. The definition of ride comfort emulation operating mode consults GB 5902, ride comfort pulse inputs running test: Car with 50Km/h divide evenly fast grow 400mm through, the triangular protruding of tall 60mm piece, at the same time the record leaves the time process curve of vertical acceleration of the car in whole process, before bedspring stiffness increases, hind if curve of time process of vertical acceleration of car centroid place pursues 7 are shown. Graph time process of angular velocity of yaw of place of centroid of automobile body of emulation experiment of 7 move with the body on the ground pursues before 8 stiffness increase, hind curve of time process of centroid place vertical acceleration by the graph 8 knowable, after suspension bedspring stiffness increases, acceleration curve and original photograph compare its positive peak value from 0.

18g increases to 0.

2g, but negative peak value however from 0.

22g is reduced 0.

14g, namely peak value of perpendicular direction acceleration from 0.

22g was reduced 0.

2g. The peak value that uses curve of perpendicular square acceleration normally inputs the evaluation index of the experiment as evaluation car pulse, peak value jumps over little ride comfort to had been jumped over, because this can think of suspension stiffness did not reduce truckload ride comfort, the program that operates firm character through increasing suspension stiffness to improve MPV is feasible. 5 summary design plan bedspring stiffness to be not worth formerly is to make truckload the main reason that stable state circumgyrate shows neuter to change direction. Operate through increasing what the suspension bedspring stiffness, diameter that increases transverse and stable staff can improve a car steady performance, the ride comfort influence to the car is minor at the same time, and do not change decorate configuration truckloadly, accordingly this plan is the first selection program that increases a car to operate certain property. Initial stage is developed in the design, adopt technique of fictitious emulation experiment, use MSC.

The MSC of Software company.

ADAMS software is can fast, accurate build truckload kinetic model, calculate through the analysis can the problem that as soon as possible discovers to exist in the design, put forward to improve plan in the light of the problem, accelerated thereby truckload the plan of development, rose to design a level. CNC Milling