Research On Lateral Stability Characteristics Of All Terrain Forest Fire Patrolling And Fighting Vehicle

All terrain forest fire patrolling and fighting vehicles is a special vehicle which drive forest-road conditions, may be used in the early forest fire patrolling and fighting. This vehicle belongs to the all terrain transport vehicle (ATV). These vehicles are widely used in forest fire protection work in Europe, the United States and other countries, but are not popular in China. Lateral stability of all terrain forest fire patrolling and fighting vehicle is its security features related to the driver's personal safety. In order to better serve the forest fire fighters, reduce the loss of the state and society because of forest fires, it is especially necessary and important to study handling characteristics theory of all terrain forest fire patrolling and fighting vehicle.To study lateral stability of all terrain forest fire patrolling and fighting vehicle, this paper built a linear 2-DOF vehicle motion model, analyzed handling characteristics of vehicle, including the steady-state response, stability analysis and frequency response characteristics. Paper analyzed the stability of vehicle based on root locus method, analyzed the frequency response characteristics of the vehicle using Matlab software, analyzed the steady-state response characteristics of the vehicle using a numerical calculation method. The results show that the studied vehicle has under-steering performance when the speed is less than 25km/h, while the speed is greater than 25km/h, the vehicle has a neutral steering characteristics.Apart from 2-DOF vehicle model, considering rolling of body, paper established 3-DOF model of all terrain forest fire patrolling and fighting vehicle. Paper analyzed change of vertical load of wheels during turning motion by 2-DOF model and 3-DOF model comparison. Paper found factors of change of unit vertical load under different degrees of freedom. The paper also analyzed rollover of all terrain forest fire patrolling and fighting vehicle, including the quasi-static rollover of rigid vehicles and vehicles with a suspension and longitudinal turning. The results show that the anti-rollover stability of vehicle is very well and the vehicle has a superior climbing ability.The development of virtual reality technology provided favorable conditions in vehicle performance study. Paper simulated motion of all terrain forest fire patrolling and fighting vehicle using ADAMS dynamic software, including simulation of the front suspension motion and simulation of the whole vehicle motion. Simulation results show that wheel parameters of the front suspension guarantee under-steering characteristic and alignment characteristic when wheels jump up and down, which are favorable to lateral stability and structural parameters of vehicle guarantee vehicle handling safely and reliable. Experiment is the most powerful way to test the theoretical derivation. Thesis built lateral stability test system and did lateral stability experiments of all terrain forest fire patrolling and fighting vehicle on different road, including the circular motion test, pylon course slalom test and turning test on off-road in forest. The research show that experimental results coincide with theoretical analysis and simulation results, indicate lateral motion of the vehicle studied is stable and may be used to patrol and fight forest fire early in forest. But road roughness in forest increase yaw motion and roll motion of vehicle. The driver should control speeds no more than 20km/h in the forest.Paper included study of theoretical analysis, simulation and the test. All research results prove all terrain forest fire patrolling and fighting vehicle has reliable lateral stability and can drive safely on off-road in forest.