Development Of Piezoelectric Stack Pump And Hydraulic Linear Actuator

In this paper, the design and performances of a piezoelectric hydraulic linear actuator consistingof a piezoelectric hydraulic pump and a hydraulic cylinder are introduced. The piezoelectric hydraulicpump utilizes a piezoelectric stack as driving component to generate high output pressure,piezoceramic stacks are potential actuators for a wide range of applications due to their widebandwidth and high block force capability. To utilize piezostack mechanisms in hydraulic actuator andother aerospace applications, the major barrier is observed to be the small stroke of the actuator. Thishybrid actuator is expected to be used in aircraft adaptive structures.In this paper, the use of a hybrid actuator driven by piezoceramic stack operating is envisaged toobtain a high force and stroke device. The relationships between output flow, pressure, hydrauliccylinder output force and chamber size was analyzed. A prototype pump was manufactured. Theoutput performances of the piezoelectric hydraulic actuator, including flow rate and pressure, weremeasured in the experiments. The results show that the performances depend on the stroke ofpiezoelectric stack, pump chamber size, diaphragm deformation, performance of check valves,operating voltage, and driving frequency, etc.A maximum output pressure of550kPa and a maximum flow rate of350ml/min were achievedin the prototype piezoelectric pump during frequency0~300Hz. The actuator can drive at a maximumspeed of24mm/s without external load and generate a blocked force of114N when a standardhydraulic cylinder of16mm is used.