Research On Anti-rollover Control Of Counterbalanced Forklift

The rapid development of modern industry has brought about progress in the animal flow industry.As an important handling machine in the logistics industry,the counterbalanced forklift is also expanding its market.The front steering and rear steering layout structure of the counterbalanced forklift chassis may cause the body swing around the hinge joint.when the swing amplitude become large,the rollover may occur.In this paper,based on the analysis of the rollover mechanism of the counterbalanced forklift,the anti-rollover control scheme is determined,the anti-rollover control strategy is proposed,and the modeling simulation and real vehicle test are carried out.The main research contents and results are as follows:(1)Based on the analysis of the rollover mechanism and process of the counterbalanced forklift,the control scheme and the executive of the anti-rollover control are determined,the hydraulic support cylinder and the active intervention of the steering is designed for the anti-rollover control.The three degree of freedom Rollover Model and ADAMS virtual prototype model of the forklift truck are established.The Zero Moment Point is calculated based on the three degree of freedom Rollover Model of the whole vehicle,and finally verified with the real vehicle.(2)Based on the geometric relationship between the zero moment point and the support plane of the forklift,the model predictive control based on zero moment point of the counterbalanced forklift is proposed.The calculation formula of zero moment point of the counterbalanced forklift is derived and the transformation of the forklift’s support plane divides the roll into three stages: safe driving,controllable danger,and critical rollover.The possibility of the forklift rollover is judged by the model prediction algorithm and the lateral stability control is carried out(3)An anti-rollover control strategy for counterbalanced forklift based on extension decision is proposed,and the anti-rollover extension hierarchical controller including upper layer extension control and lower layer execution control is designed.The upper layer extension controller divides the forklift anti-rollover control domain into a classic domain,a extension domain,and a non-domain,and determines the weight coefficient of the lower layer execution controller.The lower layer execution controller receives the weight coefficient determined by the upper layer extension controller,performs control weight distribution on the yaw rate controller and the lateral acceleration controller,and executes the command to realize the anti-rollover extension control of the counterbalance forklift.(4)Complete the schematic diagram,PCB design and physical welding of the integrated controller for the chassis of the counterbalanced forklift;compile and debug the functional program based on Freescale,and verify the anti-rollover control strategy of the counterbalanced forklift.