Application In ATV Development Based On Virtual Prototype Technology

The traditional product design is a repeated and circulatory process of prototype trial-manufacture, test evaluation and feedback design. During the every circulation of the process, the physical prototype needs to be rebuilt or modified,causing the extended product developing period and higher cost. While using the virtual prototype technology, the whole process is carried out in the digital way, avoiding the rebuilding of the physical prototype. It will doubtlessly shorten the product developing period, reduce the cost of development, enhance the quality of production, and then improve the ability of facing the customers and market demand.In this thesis, aiming at a 150 ATV a company produced, a multi-body-dynamics model of the ATV was built by applying virtual prototype technology. The handling stability and ride comfort virtual tests were performed for this model, and then the main factors that influenced the ATV's handling stability and ride comfort were found out after analyzing and evaluating the test results, and the suggestion of improvement was put forward also.Firstly, according to the drawings and some technical parameters offered by manufacturer, the main parts of the ATV were built in CATIA, and then the three-dimensional full model of ATV was built after assembling those parts. After imported the three-dimensional full model into ADAMS with required format, a multi-body-dynamics model of the ATV in ADAMS was built according to the relative restraint and movement relation of every part. Road surface files in ADAMS were created for riding comfort test according to the method of superposition of harmonic wave, and the plane road was created for handling stability test also. The engine exciting was analyzed and then the simulation for engine exciting in ADAMS was achieved.Secondly, the riding comfort virtual tests were carried out when shielded and considered engine exciting for ATV, and the results of test were analyzed and evaluated using riding comfort evaluation software created before, the results showed that when ATV runs on grit road at a low speed, the driver will feel uncomfortable and the handles are vibrate a litter, If it runs at a high speed, the driver will feel very uncomfortable and the handles vibrate obviously; when ATV runs on F grade road, the driver will feel extremely uncomfortable, the working environment is very abominable. Aiming at low frequency vibration of ATV caused by road surface roughness, the parameters of front and rear vibration damper were studied by the method of orthogonal experiment, the results indicated that the damping of front suspension is most influential to ATV riding comfort, and the riding comfort of ATV will become bad as the value of parameters increase.Lastly, based on the"test method of auto handling stability", the circle-turn, step angle input and single lane change tests were performed for ATV, and the results of simulation were analyzed and evaluated, the results indicated that ATV reveals understeer at low lateral accelerations, oversteer at middle lateral acceleration and understeer at high lateral acceleration, this property of ATV is mainly attributed to its solid rear axle. The law of the handling stability of ATV, influenced by changing the stiffness of the front and rear screw spring, the position of engine and the shift of driver body, was discussed, the results showed that the shift of driver body can improve handling stability of ATV directly and obviously.