P36 - Mass value correction method for weighing cell based on digital plD state-locking control Presentation preference:
- Event
- SMSI 2025
2025-05-06 - 2025-05-08
Nürnberg - Band
- Poster
- Chapter
- Poster Session
- Author(s)
- P. Sun, J. Wang, C. Peng - National Institute of Metrology, Beijing (China)
- Pages
- 303 - 304
- DOI
- 10.5162/SMSI2025/P36
- ISBN
- 978-3-910600-06-5
- Price
- free
Abstract
The weighing cells with electromagnetic force compensation are frequently employed for high-precision mass measurement. Digital control enables more comprehensive monitoring and facilitates the implementation of flexible control algorithms. However, due to the limited resolution of the digital-to-analog converter, small-step impacts exist in the electromagnetic force control process, adversely affecting the balancing process of the highly sensitive mechanical elastomer. The lever exhibits a discernible amplitude of vibration even in its stable stage, thereby inducing repetitive deformation in each flexible hinge and resulting in significant fluctuations of the measured values. A digital PID state-locking measurement method was proposed to reduce the influence of lever vibration on measurement results by fixing the states of input, output, and integration of the PID controller during stable stages, which disconnects the PID controller and the displacement of the mechanical elastomer. Additionally, mass values calculated using coil current are corrected by lever end displacement, leveraging the low stiffness coefficients exhibited by flexible hinges. Experimental results demonstrate that the proposed method effectively reduces fluctuation amplitudes in mass values during balance stages, thereby enhancing quality measurement accuracy.