抄録
For the advanced visual sensing system operating in a structurally unconstrained environment, it is important to measure its self-motion coincidently, because the motion of its platform is not always controlled for sensing.
In this paper, a new principle of angular velocity estimation utilizing a circular pipe filled with liquid and its associated method of measuring pressure distribution are proposed.
It is proved form Navier-Stokes equation that the gradient of fluid pressure and the centrifugal force of rotating liquid are balanced in hydrostatic condition. By applying this fact, it is shown that the difference of average pressure on two concentric cylindrical walls is in proportion to the square of angular velocity. To measure the pressure on the walls, two sheets of piezoelectric polymer film are used. The pressure applied to the membrane bent along a cylindrical surface causes the tension stress along the film and it polarizes electric charge on the both faces of the film. The charge can be collected by the evaporated electrodes and it is equivalent to calculating the average pressure on the wall.
In the first experiment, the size and material suitable for the angular velocity sensor are estimated from a fluidic numerical simulation. In the second experiment, it is proved that our trial sensor can transduce the angular velocity to the polarized charge on the surface of piezoelectric film. Even when the sensor is rotated in eccentric conditions, the final output voltage of the sensor is almost independent of it.
It is expected that this sensor can be extended to a simple three-dimensional rate gyroscope which does not require any excitation.
