A pneumatic actuator based on vibration friction reduction with bending/longitudinal vibration mode

Piston-cylinder pneumatic actuators are widely applied in various fields of automation and robotics. The sealing rings comprised in these actuators unfortunately introduce friction and affect the positioning accuracy and output force. In this work, piezoelectric actuators are built in the pneumatic actuators to introduce vibrations with lower friction force. The friction reduction effect is compared between the bending vibration mode at a resonant frequency of 1.272 kHz and the longitudinal vibration mode at a frequency of 12.133 kHz. The pneumatic actuator has a bore diameter of 6.4 mm and a stroke of 13 mm. A static/dynamic friction force measurement system is established and the test results show a maximum 66.7% reduction of stiction force and a 50.8% reduction of dynamic friction force in bending vibration mode. And the friction reduction effect also happens in the longitudinal vibration mode, with a 47.4% reduction of stiction force and a 29.7% reduction of dynamic friction force.