Noise variation test for ARX model of a heating process in essential oil extraction plant

This paper studied the robustness of ARX model by varying the noise sequence adapted to the output of a heating process. The ARX model is fitted from output data which is obtained from a pilot plant of essential oil extraction by applying steam distillation technique. The plant is supplied by 1.5kW power delivered to the heating element which then is converted into PRBS signal as input and produced output which is steam temperature from ambient (23°C) to steady state condition (93°C). The noises with different variations have been used to corrupt the validation data, which ranged from ±0.2°C to ±2.0°C. Noises and PRBS signal both are generated using Matlab software version R2008a. The study has shown that as noise is increased, there are small decrement of ARX model fit. Therefore the fitted ARX model is highly suitable for any extended contribution in controller design, prediction and simulation.