Real-time measurement of eccentric motion with capacitive sensor for hydraulic pumps

Cylindrical capacitive sensors have been developed and applied to various rotating machinery applications in the past two decades. In the hydraulic industry, capacitive sensors can also be used to measure various properties of hydraulic systems due to the change of its dielectric permittivity. Compared with competing optical, inductive, and piezoresistive transducers, capacitive sensors have many advantages, such as low cost and power usage, and good stability, resolution, and speed, etc. In this paper, a new approach that measures the eccentric motions of a hydraulic pump by using a cylindrical capacitive sensor is presented.