Real-time Temperature Control System Research Articles

Identification and parameter sensitivity analyses of time-delay with single-fractional-pole systems under actuator rate limit effect

A growing body of evidence has suggested that fractional-order models are able to describe dynamic processes with higher accuracy, such that thermal conduction processes are found to be depicted with time-delay with single-fractional-pole (TDSFP) models. Actuator rate limit phenomenon is extremely common in manufacturing due to either physical limitation or production safety guarantee. The popular step test signal in system identification has infinity derivative at step time which is not affordable by physics actuators. Thus numbers of industrial processes considered as traditional integer-order systems ignoring actuator rate limit have model mismatch to a greater or lesser extent. In this study, an identification method is proposed for TDSFP processes considering rate limit effects. Parameter sensitivity analyses are carried out to interpret the importance degree of each model parameter as well as the actuator rate limit value. Finally effectiveness of the proposed identification method considering the rate limit effect is validated on a hardware-in-the-loop real time temperature control system.

A Temperature-Control System for Continuous-Flow Microwave Heating Using a Magnetron as Microwave Source

A real-time temperature control system is designed for microwave heating of a continuous-flow substance. In this system, a magnetron is used as the microwave source, and its output power can be continuously adjusted though circuit design. A programmable logic controller (PLC) is used to procedure the temperature and power data as well as lead the whole control decision. The sample temperature can be controlled by regulating the output power of the magnetron though the control signal from the PLC during the heating process. The complete system is finally assembled into a user-friendly device, where the users can operate and monitor the heating process conveniently though a touch screen. A temperature-dependent material (Phosphoric acid) is used in system tests. The results show that the designed system can successfully achieve the desired temperature with an acceptable accuracy and stability.

Automated Temperature Control with Adjusting Outlet Valve of Fuel in the Process of Cooking Palm Sugar

In this paper, a real-time temperature control system for coconut sugar cooking is presented. It is based on a thermocouple temperature sensor. The temperature in the closed evaporator is used as a control variable of the DC servo control system for opening and closing of a valve embedded in a gas burner. The output power level, which is necessary in order to reach the target temperature is controlled by the microcontroller ATMega328P. A circuit module for control of the valve and temperature sensors as well as software for data acquisition have been implemented. The test results show that the system properly stabilizes the temperature in the closed evaporator for coconut sugar cooking in the range from room temperature to 110°C. A set point can be reached and held with an accuracy of ±0.75°C at a temperature of 110°C for 60 minutes.

Multiloop Integral Controllability Analysis for Nonlinear Multiple-Input Single-Output Processes

Multi-loop integral control is still one of the most popular control strategies in industry due to its simplicity, efficiency, offset free tracking, and capability for fault tolerance. Skogestad and Morari introduced Decentralized Integral Controllability (DIC) to investigate the decentralized unconditional stability under multi-loop integral control for square systems. However, in engineering practice, some multivariable processes may not be square, which often utilize multiple redundant control inputs for the regulation of only one single output. This study extends the concept of Decentralized Integral Controllability to non-square systems, and presents sufficient conditions for Multiple-Input Single-Output nonlinear processes based on singular perturbation analysis. The proposed controllability analysis method is applied in the control of a real time temperature control system and achieves desired temperature tracking results.

Infrared Sensor-Based Temperature Control for Domestic Induction Cooktops

In this paper, a precise real-time temperature control system based on infrared (IR) thermometry for domestic induction cooking is presented. The temperature in the vessel constitutes the control variable of the closed-loop power control system implemented in a commercial induction cooker. A proportional-integral controller is applied to establish the output power level in order to reach the target temperature. An optical system and a signal conditioning circuit have been implemented. For the signal processing a microprocessor with 12-bit ADC and a sampling rate of 1 Ksps has been used. The analysis of the contributions to the infrared radiation permits the definition of a procedure to estimate the temperature of the vessel with a maximum temperature error of 5 °C in the range between 60 and 250 °C for a known cookware emissivity. A simple and necessary calibration procedure with a black-body sample is presented.

Based on MCU AT89S52 Temperature Control System

The water temperature as the main control objectives, the real-time temperature control system is designed, in this system MCU AT89S52 is used as the core control device, integrated temperature sensor AD590 because of good linearity and high sensitivity, and A / D converter with high resolution and low noise are used for temperature acquisition,the system has achieved the temperature 40 ~ 90°C automatic control, it has set temperature display, real-time display of the current temperature function, after the actual operation shows that the system is better able to control the temperature.

MCU based real-time temperature control system for universal microfluidic PCR chip

The analysis of genetic materials in the post-human genome project era has become an ever-expanding branch of research and thus routinely employed in majority of biochemical laboratories. Most of the diagnostic research area emphasizes on polymerase chain reaction for detecting pathogenic organisms. However, the conventional polymerase chain reaction requires expensive and sophisticated thermal cycler and is not handy owing to its large dimensions. Therefore, we fabricated a continuous-flow polymerase chain reaction chip on a PDMS based microfluidic platform to ease the hardship of the conventional system. Temperature being the most crucial factor in polymerase chain reaction, was monitored and regulated by thermostatic action using an on-line computer system. Indium tin oxide coated glass platform was used for heating as it is transparent and has good thermal conductivity under the influence of DC bias. The heating circuit used an ATMega 128 MCU to control the temperature. As a result, a precise and quick heating environment was maintained on the microfluidic chip to amplify the target DNA. We successfully amplified Lambda phage and Escherichia coli DNA on our chip to prove the practicality of the device.

Application of Neural Networks and PID in on Line of Real-Time Temperature Control System

The Heat Process Trainer PT326 (Feedback UK) model is obtained by using two different techniques one by the Ziegler-Nichols approximating method and the other with the system identification method. The Data acquisition card EC641 I/O PT326 is developed and tested. it can be used as an interface between PC and any similar controlled system. The “velocity” form of the PID controller algorithm is implemented in real time where this algorithm is an ideal of solving the bump less transfer mechanism between manual and automatic control operation and the implementation of anti-reset windup algorithm. The method of back propagation neural network algorithm online gives very good results with neither steady state error nor overshoots.

A Correlation Analysis of Cooling-Induced Temperature Changes

Proper temperature control is essential for producing superior quality components and yielding high production rates in high temperature manufacturing processes. Due to the closure of machine tools such as casting dies during production, it is usually very difficult to monitor their local surface temperatures without destructively inserting thermal sensors into them. However, the measurement of cooling water temperature at the coolant outlet is relatively unproblematic. This work demonstrates that there is a correlation between these two temperatures. As an example, the effect of the local surface temperature of a casting die on the cooling water outlet temperature is analyzed from a laboratory die casting process simulator. Based on the system identification theory, a control-oriented linear time-invariant model has been developed, which correlates the local die temperature to the cooling water outlet temperature. The model enables the prediction of the local die temperature with the measurements of the cooling water temperature. Thus, it provides an alternative approach other than the destructive sensing method to acquire the local die temperatures, and the model could be applied to design a real-time temperature control system for die cooling process.