To the nonlinear dynamic response of folder system caused by the pair clearance and the bearing stiffness

the hypothesis of rigid role and spring combination is put forward

and the dynamics model of folder mechanism with clearance is established. The dynamics model which contains second order partial differential equations is solved by direct-integrating approach method. The kernel of nonlinear system analysis is the solving of system state equation. Therefore

for a general nonlinear control system

the concept of general time-state space comprising of state variables

control variables

and Time

t

is introduced. In order to solve the

state equation of nonlinear control system

at the operation point of general time-state space

the right side of the state equation can be expanded as Taylor series about time. Then the series solution of the nonlinear control state equation

for which the solution is expression in the series

can be obtained by using direct-integrating approach. Dynamics model of the folder mechanism is a typical nonlinear system. Then we obtain the curves of input quantity and output quantity of this dynamics model by the direct-integrating method.