A measurement method of piezoelectric six-dimensional force sensor for robot joints

Abstract

The invention discloses a piezoelectric six-dimensional force sensor for a robot joint and a measuring method of the force sensor. The piezoelectric six-dimensional force sensor comprises a sensor base body, an upper sealing plate, a lower sealing plate, and force sensitive elements; the sensor base body is provided with a central through hole I, four threaded through holes I which are uniformly distributed in the same circle, four threaded through holes II which are uniformly distributed in the same circle and four elastic rings; threaded holes III and wire grooves are formed in the outer sides of the elastic rings; threaded holes IV are formed in the inner sides of the elastic rings; wire threaded holes are formed in the outer sides of the wire grooves; wire adapters are mounted in the wire threaded holes; the upper sealing plate is provided with a central through hole II, four through holes III which are uniformly distributed in the same circle and four through holes IV which are uniformly distributed in the same circle; the structure of the lower sealing plate is consistent with that of the upper sealing plate; each force sensitive element comprises two adjusting gaskets, fiveelectrode plates and six quartz wafers; and the force sensitive elements are arranged in the elastic rings. The self-tightening of the force sensitive elements is realized by utilizing a special elastic ring structure, so that the force sensor is stable, reliable, high in rigidity and high in test precision.

Description

technical field [0001] The invention relates to the field of sensors and monitoring thereof, in particular to a measurement method of a piezoelectric six-dimensional force sensor for robot joints. Background technique [0002] As a key link in modern measurement technology, the piezoelectric sensor's performance directly determines the accuracy of the entire test system. Almost all types of piezoelectric sensors must be used with preload, charge elimination and reduced gap. Existing piezoelectric six-dimensional force sensors are mostly realized by means of screw pre-tightening or pressure plate-screw pre-tightening. This method mainly uses screws to generate pre-tightening force. The structure is simple and the pre-tightening force can be adjusted. Afterwards, the loosening of the screws will bring about changes in the preload, resulting in test errors. How to ensure the reliability of the pre-tightening force of the piezoelectric sensor is the key issue in improving the ...

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Problems solved by technology

[0003] The overall pretension platform type six-dimensional force sensor disclosed in Chinese patent CN1263259 has a structure that an intermediate pretension branch is added between the upper and lower platforms of the traditional Stewart platform structure, and the upper and lower platforms are tightened by using the pretension branch. The platform pre-tightens the sensor as a whole, pre-tightens each ball pair at the same time, eliminates the gap, and improves the overall rigidity of the sensor. The structure of the road is relatively complex, and it is difficult to ensure that it only bears the force along the axis, which affects the measurement accuracy

[0006] Patent CN1032395 discloses a piezoelectric quartz tool bar three-way turning dynamometer. Its structure is a high-rigidity elastic tool bar type. Two elastic half-rings are used to clamp the force-measuring crystal group to realize three-way force measurement. The instrument can only measure the three-dimensional force, and the measurement of the six-dimensional force in space cannot be realized, and its structure is a long tool holder, so there are limitations in the application environment

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