Algorithm for controlling the local airflow rate when blowing on cows in industrial livestock farming

Temperature stress affects cows’ physiological condition and productivity indicators. The experimental studies revealed the relationship between cows’ heart rate and the temperature and humidity of the environment. Local airflow contributes to the stability of animals’ physiological state indicators against the effects of high temperature and humidity. The authors prove the necessity of controlling the airflow rate for blowing on animals when environmental parameters change. For this purpose, they propose to design an algorithm for controlling local airflow to treat animals. The algorithm was developed after experimental studies of the relationship between the cow heart rate and ambient temperature and humidity at different airflow rates. The experiment was conducted on black-motley cows with an average age of 3.5 years and a weight of 590 kg. To provide a mathematical description of the analyzed relationship it was proposed to use the method of nested functions and linear multiple regression. The article presents numerical values of the parameters of mathematical models obtained from the condition of minimum sum of standard deviations of experimental and theoretical values of the heart rate for both methods. The greatest efficiency of the three-factor linear model has been determined, and the algorithm of the airflow rate control has been made based on the results of its transformation. Practical use of the algorithm consists in substituting the required value of the animal heart rate, current values of temperature and relative humidity of air with the subsequent calculation of the airflow rate. The processor-based implementation of the obtained algorithm for smooth control of the airflow rate is possible by changing the supply voltage frequency of the asynchronous electric motor.