In an invention including: a piezoelectric element (13) which generates, as a displacement, a driving force necessary for an operation of a valve body (12) which is an operating body; a displacement enlarging mechanism (14) including at least a spring element so as to enlarge a displacement of the piezoelectric element (13) which acts on the valve body (12); and a driving device (15) which operates the valve body (12) by applying a voltage to the piezoelectric element (13) to extend the piezoelectric element (13), the driving device (15) includes a first filter processing unit (15x) having an inverse function characteristic of a mechanical resonance frequency when operating the displacement enlarging mechanism (14), and is configured to apply, a voltage which reduces the mechanical resonance, to the piezoelectric element (13) through this resonance suppression processing unit (15x).

In an invention including: a piezoelectric element (13) which generates, as a displacement, a driving force necessary for an operation of a valve body (12) which is an operating body; a displacement enlarging mechanism (14) including at least a spring element so as to enlarge a displacement of the piezoelectric element (13) which acts on the valve body (12); and a driving device (15) which operates the valve body (12) by applying a voltage to the piezoelectric element (13) to extend the piezoelectric element (13), the driving device (15) includes a first filter processing unit (15x) having an inverse function characteristic of a mechanical resonance frequency when operating the displacement enlarging mechanism (14), and is configured to apply, a voltage which reduces the mechanical resonance, to the piezoelectric element (13) through this resonance suppression processing unit (15x).

In an invention including: a piezoelectric element (13) which generates, as a displacement, a driving force necessary for an operation of a valve body (12) which is an operating body; a displacement enlarging mechanism (14) including at least a spring element so as to enlarge a displacement of the piezoelectric element (13) which acts on the valve body (12); and a driving device (15) which operates the valve body (12) by applying a voltage to the piezoelectric element (13) to extend the piezoelectric element (13), the driving device (15) includes a first filter processing unit (15x) having an inverse function characteristic of a mechanical resonance frequency when operating the displacement enlarging mechanism (14), and is configured to apply, a voltage which reduces the mechanical resonance, to the piezoelectric element (13) through this resonance suppression processing unit (15x).

A fluid system includes a fluid active region, a fluid channel, a convergence chamber and plural valves. The fluid active region includes at least one fluid-guiding unit enabled to transport fluid and the fluid is discharged out through an outlet aperture of the fluid active region. The fluid channel is in communication with the outlet aperture, and includes plural branch channels. The convergence chamber is in communication with the fluid channel. Each valve includes a base, a piezoelectric actuator and a linking bar. When the piezoelectric actuator is enabled, the carrier plate is driven to move, and the stopping part of the linking bar is correspondingly moved to selectively close or open an outlet of the base. Each valve is disposed in the corresponding branch channel, and the fluid is selectively transported through the branch channels under control of the on/off states of the valves disposed therein.