A novel load ratio calculation method for calibrating force

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ABSTRACT

Welding force is a core parameter of Friction Stir Welding, whose accurate measurement and characterisation is an important guarantee for the welding quality of Friction Stir Welding. In this paper, the load ratio calculation method for calibrating force is proposed based on piezoelectric measurement system. The mathematical model and test model of piezoelectric dynamometer with parallel layout, both share-loading pillars and piezoelectric sensors, are designed based on piezoelectric sensors’ structure of four-point square layout, calibration tests for piezoelectric dynamometer are accomplished, and the calibration curves between different loading positions and output voltage of sensors with different standard forces based on Lagrange polynomial interpolation method are obtained. A novel load ratio calculation method is proposed, which solves the problem that there is larger deviation for axial output of piezoelectric sensor when force loads on different loading positions and achieves accurate measurement and calibration for external forces. And the calculated result demonstrates that the largest axial error is less than 1%, which verifies the feasibility and effectiveness of the load ratio calculation method.

KEYWORDS:

• Load ratio calculation method
• piezoelectric sensor
• variable loading point
• dynamometer

Additional information

Funding

This work is supported by the National Natural Science Foundation of China [No. 51475078 and No. 51675084], the AeronauticalScience Foundation Funded Projects [No. 20160163001] and the Basic Scientific Research Project of Central University [No. DUT17GF211], Aviation Science funds (No. 20160163001).

Notes on contributors

Jun Zhang

Jun Zhang, male, professor, mechanical engineering school, Dalian University of Technology. Research direction: Research on Sensor and Actuator Theory, piezoelectric quartz, piezoelectric ceramic mechanism, piezoelectric cutting test system, and precision instrument design and manufacturing. Research contents: piezoelectric mechanism, piezoelectric sensor, dynamometer development, force/force vector test system development.

Qingbing Chang

Qingbing Chang, male, master candidate, Dalian University of Technology. Research contents: Piezoelectricdynamometer, calibration and measurement of six-dimension force.

Zongjin Ren

Zongjin Ren, male, associate professor, mechanical engineering school, Dalian University of Technology. Research on Piezoelectric Mechanism and Piezoelectric Sensors in Aerodynamics.

Yu Tian

Yu Tian, male, Ph.D. candidate, Dalian University of Technology. Research contents: Aerospace vector force measurement.

Jun Shao

Jun Shao, male, master candidate, Dalian University of Technology. Research contents: Piezoelectricdynamometer, calibration and measurement of six-dimension force.

Xinlei Wang

Xinlei Wang, male, master candidate, Dalian University of Technology. Research contents: Piezoelectricdynamometer, calibration and measurement of six-dimension force.