Precision detection device for force standard machine, force value comparison machine and precision detection method for force standard machine

A precision detection method for a force standard machine, comprising:

• communicating a measurement device with known measurement precision to the force standard machine through a pipeline, wherein the measurement device comprises a first hydraulic cylinder having a liquid medium and a liquid level area of a known value, and a force loading device configured to, apply an acting force to the liquid medium in the first hydraulic cylinder, the force standard machine comprises a second hydraulic cylinder having a liquid medium, a second piston having an end surface which contacts with the liquid level in the second hydraulic cylinder and sliding in the second hydraulic cylinder, and a second measurement device configured to measure a value of an acting force loaded on the second piston and having an unknown measurement precision value;
• a closed space is formed by a side surface of the second piston and an inner wall of the second hydraulic cylinder, and an area of the end surface of the second piston is known or measurable;
• the pipeline is a hollow tubular structure, and both ends of the pipeline are respectively communicated with the liquid medium in the first hydraulic cylinder and the liquid medium in the second hydraulic cylinder;
• loading a first acting force into the first hydraulic cylinder by the force loading device, and obtaining a second acting force in the second measurement device by using Pascal isobaric principle;
• adding a third acting force continuously into the first hydraulic cylinder by the force loading device, wherein the third acting force ensures that a value in the second measurement device does not fluctuate;
• a ratio of the third acting force to the first acting force is a % which is a known value, and a is a nonnegative number;
• increasing an acting force value continuously into the first hydraulic cylinder by the force loading device until the value in the second measurement device fluctuates, and recording a fluctuation acting force applied by the force loading device when the value in the second measurement device fluctuates;
• and
• computing a measurement precision of the second measurement device, with the measurement precision being equal to
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• S1 is the liquid level area of the liquid medium in the first hydraulic cylinder, S2 is the area of the end surface of the second piston, F1 is the first acting force, F2 is the second acting force, F3 is the third acting force, Fn is the fluctuation acting force, and % is a percent.