An evaporatively-cooled facade system, composed of a Photovoltaic thermal (PVT), evaporative cooler, and evaporatively-cooled facade, was previously developed. In this study, a control algorithm for the system paramet...
详细信息
An evaporatively-cooled facade system, composed of a Photovoltaic thermal (PVT), evaporative cooler, and evaporatively-cooled facade, was previously developed. In this study, a control algorithm for the system parameters is implemented and applied on spaces with evaporatively-cooled facade to generate the least possible facade temperature, and con sequently maximum possible energy savings. The optimization of the system parameters is expected to overcome the limitations of using evaporative coolers in humid countries. The application of the control algorithm managed to increase the reductions in the facade heat gain from 33.5% to 38.3%. The system, integrated with the control algorithm, is then applied throughout the year on spaces located in Doha (Qatar) and Riyadh (Saudi Arabia), mimicking cities with harshly hot humid and dry weather conditions, respectively. The daily and monthly performances are further investigated in four different space orientations (i.e., north, east, south, and west). It was found that the application of the system can halve the highly glazed facade heat gain during the summer, in all orientations, and may have adverse, yet desirable effect during the winter. The integration of the control algorithm managed to reduce differences in system performance between dry and humid locations, thus generating total annual savings of up to 21.8% in any typical city of the Arabian Gulf.
This study aimed to develop a hybrid control algorithm for semiactive control devices to effectively control the drift caused by seismic loads in the superstructure of an isolated multispan bridge. First, bridge behav...
详细信息
This study aimed to develop a hybrid control algorithm for semiactive control devices to effectively control the drift caused by seismic loads in the superstructure of an isolated multispan bridge. First, bridge behavior was simulated using the Newmark method to select a semiactive control device that would be appropriate for the bridge structure. An optimal control force was selected to control the displacement and relative displacement of each superstructure element. Next, an equation of motion that employed a stochastic linearization capable of representing the nonlinearity beyond the structural linear limits was used. Further, a Bouc?Wen model was designed to simulate the nonlinearity of the structure model and the control device to configure the control logic. A hybrid control algorithm was developed to overcome the disadvantages of the clipped-optimal and Lyapunov control algorithms, which show excellent control effectiveness but experience problems during nonlinear control along with extreme manual control problems owing to their use of the Heaviside step function. The two control algorithms were used individually to make judgments, and the results of each were used to produce a three-stage signal (min., max., median). The performance of the proposed control method with the developed algorithm was verified through experimental tests. The developed hybrid control algorithm improved the performance of the two individual control algorithms and effectively controlled the behavior of multispan bridges.
In allusion to short pressure maintaining time, slow response and poor practicability of control algorithm in the current electro-hydraulic active braking system, one improved system and its control algorithm are prop...
详细信息
In allusion to short pressure maintaining time, slow response and poor practicability of control algorithm in the current electro-hydraulic active braking system, one improved system and its control algorithm are proposed. Two normally closed boost valves, pressure reduction valves and self-locking magnetic valves are added in the double pipeline between the master cylinder and ABS or ESP, respectively, and the shuttle valve is cancelled, so that the system retains the double pipeline safety design, realizes power-off and pressure maintenance, and ensures the effectiveness of the system in the manual braking mode. The response time of the system is shortened by high-pressure energy storage, two-way pressurization and pre braking. The double closed-loop control based on distance and deceleration is adopted to improve the practicability of the control algorithm. The system can maintain pressure for any long time and respond quickly. The control algorithm not only ensures the smoothness of braking, but also improves the driving safety.
With the development of technology, different types' motors and control strategies are used in motor system for electric vehicle. Their starting capability are different according by motor types, control strategie...
详细信息
ISBN:
(纸本)9781728121246
With the development of technology, different types' motors and control strategies are used in motor system for electric vehicle. Their starting capability are different according by motor types, control strategies and operating temperature. As a comparison, we analyze the starting capability of PMSM and IM in this paper. A 2D FEM integrated with control algorithm is applied to simulate the different working conditions for these motors, the starting capability with different control strategies are compared. Experiment results are consistent with the simulation results. The results show that the two motors have different maximum torque under the same protection current, and the design method described in this paper can be used as a reference for the design of electric vehicle drive motor.
This paper presents a novel active roll control algorithm for vehicle hydraulic active stabilizer bar system. The mechanical structure and control scheme of hydraulic active stabilizer bar system is detailed. The anti...
详细信息
This paper presents a novel active roll control algorithm for vehicle hydraulic active stabilizer bar system. The mechanical structure and control scheme of hydraulic active stabilizer bar system is detailed. The anti-roll torque controller is designed with Proportional-Integral-Differential (PID)+feedforward algorithm to calculate the total anti-roll torque. A lateral acceleration gain and roll rate damping are added into PID+feedforward controller, which can improve vehicle roll dynamic response. The torque distributor is introduced based on fuzzy-PID algorithm to distribute the anti-roll torque of front and rear stabilizer bar dynamically, which can improve vehicle yaw dynamics response. The actuator controller is used for realizing the closed-loop control of the actuators displacement and generating the accurate anti-roll torque. The hardware-in-the-loop simulation platform is established based on AutoBox and active stabilizer bar actuators. The hardware-in-the-loop experiment is carried out under typical maneuvers. Experimental results show that the proposed control algorithm improves the vehicle roll and yaw dynamics response, which can enhance the vehicle roll stability, yaw stability, and ride comfort.
Purpose: A control algorithm for radio-frequency-induced intestinal tissue fusion was developed to explore the effects of different control parameters on intestinal tissue fusion. Materials and methods: Radio-frequenc...
详细信息
Purpose: A control algorithm for radio-frequency-induced intestinal tissue fusion was developed to explore the effects of different control parameters on intestinal tissue fusion. Materials and methods: Radio-frequency-induced fusion was performed on ex vivo small intestine tissue. The effect on the fusion was observed by changing the control parameters (power, interval time, and terminal impedance) in the algorithm. The quality of fusion was evaluated using the burst pressure and thermal damage measurement. Histological evaluation was used to assess the fusion quality indirectly. Results: A maximum burst pressure of 8.460 +/- 0.2674 KPa was acquired when the power was set to 100 W, the interval time was set to 2000 ms, and the terminal impedance was set to 50 omega. Moreover, the thermal damage range increased with an increase in power but decreased with an increase in the interval time and terminal impedance. Furthermore, the thermal damage range and temperature were presumably related. Conclusions: For an ex vivo small intestine tissue, the appropriate control parameters could be set when the power was approximately 100 W, the interval time was approximately 2000 ms, and the terminal impedance was approximately 50 omega. This study could provide a basis for the selection of control parameters for intestinal tissue fusion.
When the state of the robot reaches the smooth sliding plane, the current algorithm will generate high-frequency chattering, resulting in larger tracking error and longer response time. To solve these problems, we hav...
详细信息
When the state of the robot reaches the smooth sliding plane, the current algorithm will generate high-frequency chattering, resulting in larger tracking error and longer response time. To solve these problems, we have proposed a trajectory tracking and control algorithm based on exponential reaching rate. The coordinate system of parallel robot system is established, and the kinetic energy and potential energy of the system are calculated. The results are brought into the Lagarnge equation to find the dynamic model of the system. The power amplifier, electro-hydraulic servo valve, hydraulic cylinder and its load are taken as generalized controlled objects, and the hydraulic servo system model is established. The exponential approaching rate is introduced to design the dynamics model and the trajectory tracking sliding controller of the hydraulic servo system model. By adjusting the upper and lower bounds of the external disturbance of the controller, the control rate is changed, the buffeting occurrence is reduced, and the response time is shortened, to realize the low error tracking of any trajectory of the robot. The experimental results show that the trajectory of the robot can be adjusted quickly and the desired trajectory is better tracked by the end.
This study examined a method to reduce energy consumption in office buildings. Correspondingly, an optimal control method was proposed for heating, ventilation, and air conditioning (HVAC) systems via two control algo...
详细信息
This study examined a method to reduce energy consumption in office buildings. Correspondingly, an optimal control method was proposed for heating, ventilation, and air conditioning (HVAC) systems via two control algorithms that considered the indoor thermal environment. The control algorithms were developed by considering temperature and humidity as the factors of the indoor thermal environment that influence the control of HVAC systems and the predicted mean vote comfort ranges. Furthermore, an experiment was performed using office equipment that incorporated the two control algorithms for HVAC systems, and the correlation between changes in the thermal environment within the office and the occupant's comfort levels was estimated via an actual survey. The results demonstrated that the proposed control method for HVAC systems, which considered the comfort ranges of temperature and humidity and the thermal adaptation capability, can efficiently maintain the occupant's comfort with lower energy usage compared with conventional HVAC systems. Thus, the use of the control method contributes to the reduction of total energy consumption in buildings with HVAC systems.
Two new control algorithms based on MSP430 microcontroller unit(MCU)were developed to improve the performance of a fertigation system controlled by the electrical conductivity(EC)value of an irrigation nutrient soluti...
详细信息
Two new control algorithms based on MSP430 microcontroller unit(MCU)were developed to improve the performance of a fertigation system controlled by the electrical conductivity(EC)value of an irrigation nutrient solution in a *** first algorithm is incremental proportional-integral-derivative(PID),and the second one is a two-stage combination algorithm(PID+fuzzy).With an improved multi-line mixing Venturi tube,several sets of experiments were conducted for a fertilizer absorption test under two conditions,namely,various suction lines and different EC target values *** the first condition,with an EC target value of 2.0 mS/cm and opening of various suction pipes,the steady-state times are 186 s,172 s,134 s,and 122 s corresponding to the opening of one to four suction pipes,respectively,for PID+fuzzy *** corresponding values are 220 s,196 s,158 s,and 148 s for incremental PID *** the second condition,four suction pipes are opened with different target EC values of 1.5 mS/cm,2.0 mS/cm,and 2.5 mS/cm,and the shortest response time and the minimum overshoot were obtained for PID+fuzzy control when the target EC value is 1.5 mS/cm,which are 96 s and 0.18 mS/cm,*** the corresponding values are 112 s and 0.4 mS/cm,respectively for incremental PID *** two control strategies can adjust the EC value to the target value for real-time control,but the combination control algorithm can be implemented more rapidly,accurately,and steadily with a small overshoot compared with incremental PID *** combination algorithm(PID+fuzzy)control strategy also possesses better properties for automatic fertigation control in greenhouses than the incremental PID control strategy,the combination algorithm provides an optimal way of water and fertilizer management for crops in greenhouses which will contribute to water and fertilizer saving.
In practical applications, it is difficult for the control parameters of the proportional integral derivative (PID) thermal controller to be self-tuning online. As the control object or environment changes, the contro...
详细信息
In practical applications, it is difficult for the control parameters of the proportional integral derivative (PID) thermal controller to be self-tuning online. As the control object or environment changes, the control parameters are required to change accordingly. An intelligent thermal controller based on the deep deterministic policy gradient, called DRLTC, is proposed. Two types of reinforcement learning agents were designed in DRLTC, which can automatically adjust the control parameters of the thermal controllers and self-optimize online after training. Both theoretical and experimental results revealed that, when the control object was the main mirror support, the DRLTC achieved a control precision of 0.01 degrees C. Additionally, the steady-state error was reduced by 40.2, 62.5, and 33.3% in the simulation and by 5.6, 80.6, and 85.7% in the experiment, compared with the reinforcement learning PID, neural network PID, and adaptive PID control based on fuzzy control, respectively. When the control object was changed to the main mirror installation, the DRLTC achieved a control precision of 0.02 degrees C, and the steady-state error was reduced by 87.5, 91.7, and 90.9% in the simulation and by 80.2, 90.6, and 85.7% in the experiment, compared with the above-mentioned thermal control strategies, respectively. Therefore, the DRLTC has better universality, has stronger robustness, and saves more energy.
暂无评论