Research Of Lateral Stability Control Of Counterbalanced Forklift Truck Based On Co-simulation

As the most commonly used material handling machinery,counterbalanced forklift truck has been widely used in various fields.Because of the special characteristics of the hinging structure between the frame and the steering bridge,the cargo contained in the hoisting mechanism will be shifted,which will lead to the change of the center of gravity of the whole forklift,so the lateral stability is poor.If turned around accidently or improper operated,counterbalanced forklift truck is prone to lose the lateral stability and lead to roll-over accident,because the forklift center of gravity is beyond the stability of the region.Study on lateral stability of counterbalanced forklift truck is still at the primary stage at home up to now.Most forklifts are also not equipped with lateral stability control system products and security is very low.In this dissertation,the lateral stability of a three-tons counterbalanced forklift truck was studied,the key factors affecting the lateral stability of forklift were determined.A virtual prototype model of counterbalanced forklift truck was established based on ADAMS and the simulation was carried out under various working conditions.After the putting forward of the control strategy of the roll grading,the fuzzy controller and variable universe fuzzy controller of roll grading were designed in Simulink,and the simulation is carried out based on ADAMS and Simulink.Finally,the design of the lateral stability control system of counterbalanced forklift truck and the real forklift test were completed.The main work and results are as follows:(1)According to the structural characteristics of the counterbalanced forklift truck,the main influencing factors and the roll mechanism of the lateral stability were studied,and the seven-degree-of-freedom model and the differential equation of motion were established.So the critical condition of the latsral instability was analyzed.(2)The virtual prototype model of counterbalanced forklift truck was established based on ADAMS,and the steering mechanism was optimized.A new type of three-link hydraulic supporting adjusting mechanism was designed as the anti-roll actuator.The lateral stability kinematic and dynamic simulation of forklift truck was carried out under various working conditions.The variables which characterize the degree of roll were selected.The range size of the variables and the threshold under the roll were determined.(3)According to the analysis and simulation results,the lateral stability controlstrategy of roll grading was proposed,and the first-order roll fuzzy controller and the second-roll fuzzy controller were designed based on the fuzzy control algorithm.By means of variable fuzzy adaptive control theory,the fuzzy controller of the gradient hierarchical variable universe was designed.(4)Based on the joint simulation of ADAMS and MATLAB/Simulink,the European standard condition of dynamic stability verification of counterbalanced forklift truck was used to verify that roll back fuzzy control can effectively improve the tilting situation of forklift.(5)The design of circuit schematics,PCB plate and prototype of the counterbalanced forklift lateral stability control system was completed,and the real forklift truck was tested.Because of the high degree of fit between the experimental data and the simulation results,the accuracy of the vehicle virtual prototype model and the effectiveness of the lateral stability control system and the lateral stability control system were verified,so the design goal of the subject was achieved.