Research On Control System Of Ascending Platform Work Vehicle

The Ascending Platform Work Vehicle is a special vehicle used to lift worker and equipment to the predetermined positon quickly and accurately.It is widely used in many industries such as municipal construction,engineering construction,port,and ship and so on.With the continuous expansion of the operating range and the continuous increase of the working height,whether the working platform can maintain the horizontal state in real time,accurately,stably and reliably,and thus ensuring the safety of the worker is an important performance index to evaluate the control system.The following is the main content of this paper's research on the control system of the ascending platform work vehicle:1.For the flexible boom characteristics of the ascending platform work vehicle,in this paper,the flexible multi-body system dynamics theory is used to establish the mathematical model of the boom system,and the Lagrangian equation is substituted for solving and simulating.The influence of the elastic deformation of the platform flexible boom on the control accuracy of the working platform is analyzed.It lays a foundation for the subsequent research on the automatic leveling control of the working platform.2.According to the structural characteristics and working principle of the leveling system,the kinematics equation and dynamic equation of the leveling mechanism are established,and then the simulation model is built by the AMESim software for the boom system and leveling system of the ascending platform work vehicle.The results verify the correctness of the simulation model,and provide a verification platform for the improvement and optimization of the oil circuit configuration and traditional control methods of the leveling system.3.Due to the time-varying nonlinear characteristics of the leveling system and the low natural frequency of the leveling proportional valve,the further improvement of the open-loop gain is restricted,and the traditional control scheme achieve poor leveling accuracy,Under the premise of ensuring the stability of the working platform.in this paper,to the introduction of load pressure compensator in the hydraulic circuit makes the control current and output flow of the leveling valve proportional and constant;introduce a time-varying nonlinear compensation algorithm related to the working state,which makes the time-varying nonlinear relation between the leveling valve output flow and the platform angular velocity control gain become linear;the angular velocity feedforward compensation is introduced to improve the system response speed and reduce the tracking error of the flexible boom.4.In this paper,the simulation model and experimental platform are built based on the GTBZ26S ascending platform work vehicle.Based on different control strategy proposed in this paper and under different conditions simulated and experimental test,the simulation results and experimental results are compared with the experimental results obtained by the traditional PID control method,achieving the desired effect,can satisfy the demands of safety,stability and accuracy.and verified the feasibility and rationality of the proposed control strategy.