This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
On-Line Process Parameter Identification for Control of Variable Rate Nitrogen Fertilization
Annotation ability available
Sector:
Language:
English
Abstract
Variable rate nitrogen fertilization (VRNF) is a technique being developed for agricultural applications in recent years. In designing a controller for VRNF system, it is hoped that the process parameters, which are difficult to measure, could be identified on-line so that the model-based digital controllers or adaptive controllers could be used to achieve better system performance.
In this paper, the problems associated with the on-line process parameter identification for the control of variable rate nitrogen fertilization are analyzed. Simulation studies and experimental tests were conducted to determine a suitable parameter estimation algorithm and the influence of pseudo random binary signal and external torque disturbance on the parameter identification accuracy. The results from the simulation and experimental studies revealed that the recursive least square algorithm is most suitable for parameter estimation. The parameter identification accuracy decreases with increasing torque disturbance level. The pseudo random binary signal should have a magnitude which is 20 percent of the set point input, and a switching interval close to the dominant time constant of the process.
Citation
Li, Y. and Wilson, J., "On-Line Process Parameter Identification for Control of Variable Rate Nitrogen Fertilization," SAE Technical Paper 932424, 1993, https://doi.org/10.4271/932424.Also In
References
- Adsett John 1990 Automated Field Monitoring of Soil Nitrate Levels Ph.D Thesis University of Saskatchewan Saskatoon, Canada
- Li Yu Kushwaha R. L. Zoerb G. C. 1992 a Design and Modelling of a Digital Control System for Variable Rate Nitrogen Fertilization ASAE Paper 923035 American Society of Agricultural Engineers St. Joseph. MI. 49085
- Li Yu 1991 Development and Analysis of a Digital Control System for Variable Rate Nitrogen Fertilization M. Sc. thesis University of Saskatchewan Saskatoon, Canada
- Li Yu Kushwaha R. L. Zoerb G. C. 1992 b Design of the Model-Based Controllers for a Digital Control System for Variable Rate Nitrogen Fertilization CSAE Paper 92322 Canadian Society of Agricultural Engineers
- Sinha N. K. Kuszta. B. 1983 Modelling and Identification of Dynamic Systems Van Nostrand Reinhold Electrical/Computer Science and Engineering Series New York
- Rolf Isermann 1981 Digital Control Systems Springer-Verlag Berlin Heidelberg New York