Uncertainty shift in robust predictive control design for application in CAV air-conditioning systems

2011 ◽  
Vol 32 (4) ◽  
pp. 329-343 ◽  
Author(s):  
Gongsheng Huang ◽  
Tin-Tai Chow
Keyword(s):  
Air Temperature ◽  
Predictive Control ◽  
Air Conditioning ◽  
Prediction Models ◽  
Control Design ◽  
Pi Control ◽  
Control Law ◽  
Original Design ◽  
Input Structure ◽  
Air Conditioning Systems

Constant-air-volume (CAV) air-conditioning systems consist mainly of two local processes: an air-handling process and a room temperature process. A robust model predictive control (RMPC) strategy was developed for CAV air-conditioning systems, which adopted two uncertain first-order plus time-delay models to describe the dynamics of the local processes and used a linear matrix inequality (LMI)-based optimisation technique to optimise the control law. This paper develops a new control design, which reformulates the prediction models by shifting the uncertainties of the first model into the second one, and then uses the reformulated prediction models in the RMPC strategy. This paper will show that compared with the original design, the new control design can enhance the feasibility of the optimisation of control law, reduce the computational burden of the optimisation and also remove the requirement of a sensor for supply air temperature in the original design. Practical applications: The new design method is a further development of a RMPC strategy presented in Xu et al.13 It inherits the benefits of the original control design for practical application, i.e. uncertainties and constraints can be dealt with simultaneously in the design and the robustness of the controlled system can be enhanced. The new design improves the optimisation feasibility, reduces the computational complexity and does not need to measure the supply air temperature. When the new design is adopted to replace the traditional PI control, there is no necessity to change the existent input structure of the PI control. Hence, the new design can be realised in practice easier than the original design.

scholarly journals GPC-Based Stable Reconfigurable Control

2003 ◽  
Author(s):  
Jianjun Shi ◽  
Atul G. Kelkar ◽  
Donald Soloway
Keyword(s):  
State Space ◽  
Predictive Control ◽  
Flight Control ◽  
Actuator Saturation ◽  
Control Design ◽  
Generalized Predictive Control ◽  
Control Law ◽  
Reconfigurable Control ◽  
Space Formulation ◽  
The Stability

This paper presents development of multi-input multi-output (MIMO) Generalized Predictive Control (GPC) law and its application to reconfigurable control design in the event of actuator saturation. The stability of the GPC control law without reconfiguration is first established using Riccati-based approach and state-space formulation. A novel reconfiguration strategy is developed for the systems which have actuator redundancy and are faced with actuator saturation type failure. An elegant reconfigurable control design is presented with stability proof. A numerical example with application to reconfigurable flight control is presented to demonstrate the results presented in the paper.

Design and Experimental Evaluation of a Data-Oriented Generalized Predictive PID Controller

2016 ◽  
Vol 28 (5) ◽  
pp. 722-729 ◽  
Author(s):  
Zhe Guan ◽  
◽  
Shin Wakitani ◽  
Toru Yamamoto ◽  
Keyword(s):  
Predictive Control ◽  
Pid Controller ◽  
Control Design ◽  
Point Of View ◽  
Generalized Predictive Control ◽  
Control Law ◽  
Control Parameters ◽  
Proportional Integral Derivative ◽  
Molding Machine ◽  
Output Data

[abstFig src='/00280005/15.jpg' width='300' text='Schematic figure of data-oriented GPC-PID controller' ] This paper presents a data-oriented technique for designing a proportional-integral-derivative (PID) controller based on a generalized predictive control law for linear unknown systems. In several control design approaches, a model-based control theory, which requires accurate modeling and identification of the plant, is used to calculate the control parameters. However, in higher-order systems and/or systems with an unknown time delay such as chemical industries and thermal industries, it is difficult to model or identify the plant accurately. Over the last decade, data-oriented techniques in which the online or offline data are utilized have been attracting considerable attention. Designing the controllers for unknown plants based on only the input/output data is the main feature of this technique. In this study, controller parameters are first obtained by using a generalized predictive control law with the data-oriented technique, and are converted to PID parameters from the practical point of view. The proposed method is validated experimentally using a real injection-molding machine. The results demonstrate the efficiency of the proposed method.

Experimental investigations on the performance of solar powered cabin air ventilator

2015 ◽  
Vol 12 (6) ◽  
pp. 607-618 ◽  
Author(s):  
Sudhir Chitrapady Vishweshwara ◽  
Jalal Marhoon AL. Dhali
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Air Conditioning ◽  
Temperature Drop ◽  
Ambient Air ◽  
Comfort Level ◽  
Cabin Temperature ◽  
Solar Powered ◽  
Air Conditioning Systems ◽  
Air Exchange

Sultanate of Oman witness a long summer with mostly clear blue skies and typically higher ambient temperatures as seen in other GCC countries. This type of environment warrants the use of high capacity and reliable air conditioning systems, both at resident buildings and vehicles. During summer, cars parked directly under the sun, experience a very high temperature rise inside its cabin in the range of near to 50 °C. This high cabin air temperature often causes thermal discomfort to passengers entering the parked car and also has a serious impact on the cars air-conditioning systems, as it takes longer time to bring back the thermal comfort inside the cabin. The studies also revealed that the high cabin temperature often causes health hazards to occupants, especially to infants. Current research paper, reports an experimental study carried out on a parked car, with instrumentation to identify the various the temperature zones inside the car cabin. This experiential study is aimed to improve the thermal comfort inside the cabin through solar powered cabin air ventilator for effective management of cabin air temperature. The study was carried on a chosen vehicle parked at a set direction and location exposed to day long sunlight at Muscat for considerable period of time. Firstly, the study identified the various temperature zones inside the car cabin and ventilation driven with a 10 Wp solar panel was developed to accomplish the required air exchange inside the cabin, along with continues instantaneous heat rejection through steady air exchange between inside and outside environment. A simple ventilator was developed by means of two fans which drove out the hot trapped air and a secondary fan to cool down the temperature inside the car by providing fresh air for limited time. The experimental investigation showed that the vehicle cabin temperature was typically 10 °C lower when ventilator was turned on. On a typical day on month of May, the cabin air temperatures was approximately 21 °C higher than the ambient air temperature, while with the developed ventilator the difference between the cabin and outside air temperature was reduced by 50% approximately. With the ventilator in operation, it was observed that time taken to reduce the cabin air temperature through vehicle air conditioning system to a satisfactory level was much quicker; typically it took less than the half of the time compared to those values tested without ventilator. Thus indicating, the power saving potential of the developed system as the desired level of thermal comfort can be achieved within the shorter period of time. The reduction in time taken to cool down the cabin temperature to the acceptable limits has direct two fold effects; firstly, the fuel consumption for cooling purpose is reduced and secondly, increased thermal comfort level inside the cars cabin. However, the temperature drop pattern was not similar all around the cabin, due to the varied level of cabin sunlight exposure. Temperature drop at the front of the car was lower than in middle and rear of the car. From the study it can be concluded that, with solar powered ventilator, the temperature inside the car was nearly 10 °C lesser compared to cabin without ventilator and it also helps in to bring back the thermal comfort inside the cabin nearly within half time vis-à-vis cabin without ventilation.

Sign in / Sign up

Export Citation Format

Share Document