Wheel Loader Instability Regular Research Based On Stable Angle

Articulated wheel loader is large wildly used construction machinery which is featured by high efficiency and good mobility. But wheel loader used to working in poor working environment, mass, structure and C.G. position changed during work, as same as load impulse instantaneous, and because of these reasons wheel loader instability accidents are easily happened. Articulated wheel loaders are forced to add cockpit with ROPS internationally which cannot avoid instability accidents fundamentally. Due to the large differences in aspects of frame structure and working environments between road vehicles and wheel loader, the instability pre-warning theory that commonly used by road vehicles cannot applied on wheel loader. Therefore, researches of wheel loader’s instability regular and techniques of instability active pre-warning model have important significances on achievements of working safety and completely instability accidents protection. This article focus on issues that mentioned above, mainly carried out of following works:1. This article has analyzed research status of road vehicle, off-road vehicle and articulated vehicle in vehicle roll-over protection in detail, the summary and comparison of most commonly used vehicle instability index and instability pre-warning methods have been done. Also, the further deeply discussion of roll-over process and methods of wheel loader with swing axle have been launched.2. Against wheel loader’s frame structure and working features and combine with instability theory of wheel loader, a instability threat index that could applied on wheel loaders, named "Stable Angle" has been proposed and the calculation process has been derived in detail.3. Two1:1prototype models according to specific wheel loader Model1&Model2has been built, prototype models multi-body dynamic simulation have launched in different working conditions by using ADAMS software and Instability threat index "Stable Angle", regular of instability also have been studied in-depth. Based on two prototype models, this article has discussed the influences of body structure on vehicle stability. Studies shows longer front frame of wheel loader tends to be lateral instability more likely and shorter front frame wheel loader tends to be longitudinal instability more likely.4. Instability threat index of stable angle has good performance in vehicle status indicating, vehicle safety and first&second order instability by prototype simulation analyzing According to test data, Model1and Model2prototype occurs first order instability when stable angle reaches80.5and79.7respectively, second order instability happened when stable angle reaches90.5. Real vehicle tests were launched by supporting of self-developed experimental test system, the maximum error between real vehicle tests measured data and ADAMS simulation data are8.9%, the availability of instability threat index based on Stable Angle were validation preliminary.In this article, instability threat index and instability regular of wheel loader belongs to precondition and foundation of vehicle active pre-warning which provides a reference ideas and research directions for subsequent research of wheel loader active safety system in-depth.