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Study On The Attitude Control For Semi-Track Air-Cushion Vehicle On Soft Terrain

Posted on:2012-10-22Degree:DoctorType:Dissertation
Country:ChinaCandidate:D XieFull Text:PDF
GTID:1112330362458308Subject:Vehicle Engineering
Abstract/Summary:PDF Full Text Request
The semi-track air-cushion vehicle (STACV), which effectively combines air cushion technology and semi-track walking mechanism, can be used to improve transportability of vehicles at soft terrain areas, such as beaches, rivers, deserts, swamps, etc. Due to the change of speed, the unbalance of load, the unevenness of road and the leakage of skirt, the vehicle body pitch and roll will increase during the STACV driving, which will indirectly increase the total power consumption, driving resistance and even difficult to travel. Therefore, the research of how to coordinate the relationship among the vehicle power consumption, driving performance and vehicle driving attitude control is of great value.Based on the National Natural Science Foundation of China (NSFC) entitled"Research on load distribution and driving attitude control of Semi-Track Air-Cushion Vehicle on soft ground"(No. 50675135), the study on the attitude control for the STACV on soft terrain is carried out, especially emphasized on the structure realization of the STACV, air cushion system performance test, modeling of multi air cushion system for vehicle body attitude control and attitude control scheme of the STACV.After reviewing the research status of air cushion vehicle and its control technology and the problems in controlling the vehicle, a full vehicle dynamics model and corresponding virtual prototype are establishment. Then, a prototy of the STACV is built up. Through the air cushion system related test on the prototype and the corresponding fluid dynamics simulation, the performance of multi air cushions system is studied using fluid dynamics simulation and forward and reverse characteristics of neural network models are built up for them.Combining the integrated control and hierarchical control method, a vehicle attitude control framework is proposed for the STACV by taking into account the vehicle power consumption, diring control and vehicle body attitude control together. In feedworward ontrol loop, the optimal power is sovled by using the new proposed hybrid generalized extremal optimization algorithm (HGEO) and the resulting generalized force vecetor for feedforward control is the basic object generalized force which can ensure the basic vehicle running status; in the feedback control loop, the model predictive controller (MPC) is used to solve the target generalized feedback force vector which is the modification of the basic object generalized force according to the vehicle running status and can further ensure the vehicle running target; in the generalized force distribution module, the ultimate target of the generalized force is assigned to the target dirving torques and the target air cushion pressures by sequential quadratic programming (SQP); the resulting object air cushion pressures is further converted into the requied fan rotational speed and variable orifices opening using the reverse neural network model of the air cushion system. The simulation results for typical operation conditions show that the established vehicle attitude controller has good control performance, and at the same time the necessity of each control module in the control framework is also validated.The nonlinear air cushion system and the interaction between wheels/semi-tracks and terrain cause the coupling among longitudinal, lateral and vertical dynamics of the STACV. The resulting control problem is one of the technical difficulties to be solved in vehicle engineering fields. The proposed vehicle attitude controller takes into account these coupling relationships, which not only combines vehicle dynamics, terrain mechanics, experimental study, computational fluid dynamics, virtual prototype technology, optimization and advanced control theory, but also balances the power consumption of the vehicle, driving and vehicle body attitude control. It has certain reference value for both the field of engineering thchnology and future off-road vehicle control system research.
Keywords/Search Tags:Semi-track air-cushion vehicle, Air cushion system, Attitude control, Hybrid generalized extremal optimization, Model predictive control
PDF Full Text Request
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