The large load loss of piezoelectricity pumps leads to fluid energy in the fluid chamber during fluid transportation. In this paper, the output performance of a piezoelectricity pump is improved by changing the structure parameters of the fluid chamber to reduce the fluid load. The mechanism of fluid flow energy loss in the body cavity of hydraulic pumps is simulated and analyzed, and the influence of the dimensions of the inlet and outlet valves and the height of the cavity on fluid energy loss is obtained. The flow rate and pressure of inlet and outlet valves with different cavity heights and different driving frequencies are obtained. The results show that the flow rate and output pressure of the hydraulic pump are optimized when the cavity height is 3 mm, and the inlet and outlet valve diameters are 2.5 mm.

In order to solve the displacement regression phenomenon of piezoelectric viscous-slip actuators, this paper proposes a lever-type flexible hinge mechanism that uses two sets of piezoelectric stacks to move the slider in both directions and efficiently suppress the displacement regression phenomenon. First, the overall dimensional parameters of the drive are designed, the device is modeled using 3D software, and the driving principle is analyzed. Then a theoretical model is built based on the lever amplification principle to derive the relevant expressions for the piezoelectric viscous slip actuator under sawtooth wave type voltage signals. The piezoelectric stack is simulated and analyzed with COMSOL Multiphysics to obtain the modal and stress-displacement clouds of the flexible hinges. Finally, a prototype was built for experimental testing, and the slider in the device was able to achieve smooth motion and effectively suppress the displacement regression phenomenon. The input voltage of piezo stack A is 100 V, the input voltage of piezo stack D is 150 V, the input frequency is 212 Hz, the maximum output displacement of single-step drive is 46.6 μm, and the amplification ratio of flexible hinge input to output is 2.59. The piezoelectric viscous-slip actuator was verified to be able to achieve effective drive and suppress back-off.

To realize flexible output and fast response in Braille spotter contacts, in this study, a flexible contact structure of piezoelectric hydraulic amplified Braille spotter was designed. First, the structure and working principle of the piezoelectric Braille contact were designed and analyzed. Next, the mechanical model of the system was established, the expressions for the output displacement and amplification ratio of the flexible film and piezoelectric oscillator were derived, and the parameters affecting the output displacement and amplification ratio were determined. In addition, piezoelectric oscillator vibrations and the deformation of the flexible film of the hydraulic amplification structure were simulated using COMSOL Multiphysics software. Finally, the prototype was fabricated and tested experimentally. The results showed that the displacement of the flexible contact was 0.402 mm at a driving voltage and resonant frequency of 170 V and 282 Hz, respectively, and a displacement amplification of 10.1× was achieved. The response time of the piezoelectric Braille contact is less than 5 ms, which meets the requirement for application in tactile reading.