Based on a modified Coulomb friction force model

the nonlinear stability characteristics of pneumatic valves' chatter were theoretically analyzed

and the regions of instability

local and global stability were developed

which interpreted the inevitability and occasionality of valve chatter at the local stable region. Taking a safety valve as the research object

the AMESim model of the safety valve system was constructed

the local and global stability regions

and the effect of Coulomb friction were obtained. Moreover

validation of the stability analysis was performed by the pneumatic experiment of the safety valve under various friction forces and various disturbance conditions. Results indicated there was a local stability region of small disturbance stability and large disturbance instability

showing that the safety valve was stable at exhaust experiment and unstable at exhaust and vibration experiment from the view of simulation. Moreover

with the increase of the Coulomb friction force

the stability and anti-disturbance ability of the safety valve system were enhanced

and the validation of nonlinear stability analysis was improved by the exhaust and vibration experiment of the safety valve.