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Copyright of Control Theory & Applications / Kongzhi Lilun Yu Yinyong is the property of Editorial Department of Control Theory & Applications and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Conditioning temperature is one of the key factors in the quality of feed pellets during feed processing. It is a high demand to maintain the constant conditioning temperature. Specifically, too high conditioning temperature can lead to the inactivation of heat-sensitive ingredients, such as probiotics, whereas, too low conditioning temperature can be found in the incomplete sterilization of the starch paste. In this study, a Proportion Integration Differentiation (PID)-based control system was developed to control the conditioning temperature of the feed pellets during processing. The whole unit consisted of a control system, steam piping, and a pelletizer. The control system with a Programmable Logic Controller (PLC) and a touch screen was utilized to control the start/stop of the pelletizer and the opening of the electric regulating valve. The process parameters of the pelletizer were also automatically collected, according to the given time interval. A temperature sensor was installed at the outlet of the pelletizer. The PT100 temperature sensor was used to collect the conditioning temperature of the material at the outlet of the temperature in real time. Subsequently, the collected data was fed back to the PLC. The PID closed-loop control algorithm was utilized to calculate the electric actuator again after the appropriate adjustment of the parameters. The stable control of tempering temperature was realized to change the steam flow into the temperature. A systematic analysis was made to obtain the convective heat exchange process between the mixed feed and steam at temperature. A theoretical model of heat transfer was established to obtain the specific parameters using the step response curve method. After that, the data curve was processed (R² = 0.976) to obtain a control model between the electric proportional control valve and the tempering temperature in the control system. As such, a large influence of special points was avoided on the experimental data after processing. Furthermore, the simulation analysis was carried out to determine the optimum parameters for the PID control using the Simulink platform. A comparison was performed on the response curves from three PID parameter regulations, namely the Z-N regulation, the decay curve method, and the critical proportional method. Finally, the critical proportional method was found to present the best control effect, in terms of the overshoot and regulation time in the dynamic performance indicators with the PID parameters (proportionality coefficient Kp=52.7, integral coefficient Ti=6.4, and differential coefficient Td= 1.6). The response time of the PID controller obtained by the critical proportionality method was 14 s and the overshoot was 3.3 ℃. Taking the lactating sow meal as an example, a series of prototype tests were carried out on the pelletizer. Specifically, the lactating sow meal was first crushed with the 1.5 and 2 mm sieves. The moisture content of the mixture was 10.17%, while the tempering temperature was set at 75, 80, and 85 °C. The tempering temperature was maintained within the set range after stability. Subsequently, the tempering temperature of 80 °C was chosen for the stability test. The tempering temperature was recorded every 1min during the test. The basically stable tempering temperature was achieved in the whole test process, which was controlled within (80±1) ℃, indicating the small average relative error and coefficient of variation of temperature. Therefore, the stable control of system temperature can be expected to automatically collect the pelletizing production data. Anyway, the control system can be expected to serve as the rapid response and real-time control of tempering temperature in the pelletizing process. Furthermore, the processing operation was simplified to improve automation in pelletizing production. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Dalian University of Technology / Dalian Ligong Daxue Xuebao is the property of Journal of Dalian University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Liquid Crystal & Displays is the property of Chinese Journal of Liquid Crystal & Displays and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Because the actuator composed of the dielectric elastomer has a viscoelastic effect during the driving process of the soft robot, which makes it difficult to accurately control the robot, a kind of beetle antennae search (BAS) algorithm optimization PID was proposed. The control algorithm was used for precise control of the soft robot. Firstly, the rheological model was used to build the dynamic model of the dielectric elastomer actuator (DEA). Secondly, the use of the BAS algorithm had a strong global optimization ability and a single optimization strategy to convert the PID controller parameters into BAS algorithm in the three-dimensional space. Finally, the PID parameters in the iterative process were optimized. The experimental results show that the maximum tracking error of sine triangle wave is 0.95 mm and 1.08 mm. Compared with other control methods the proposed method has better control accuracy of the actuator. [ABSTRACT FROM AUTHOR]

Environmental factors including temperature, humidity, and gas atmosphere directly determine the daily performance, growth rate, and immune status of livestock and poultry in a farm. It is highly urgent to detect the factors for real-time monitoring the health state of livestock and poultry, particularly the relationship between environmental factors and health state. Therefore, a healthy aquaculture pattern can be developed to optimize the breeding environment. In this study, a mobile intelligent monitoring platform was established to detect the key environmental factors within the whole area. An integrated sensor system was installed in the fixed important points. A four-wheel trolley with sprocket wheels was used to drive the platform. The motor and transmission components were installed inside the car body in the need of waterproof and anti-corrosion. The upper side of the car was sealed with a cover plate, and only the integrated sensor system installed on a foldable telescopic mechanism that needs to be exposed was fixed on the plate. Height adjusting of an integrated sensor system was performed via changing the folding angle and telescopic length of a foldable telescopic mechanism. The sensors were assembled separately and disassembled conveniently, in order to facilitate repair and maintenance, and even the integrated sensor system was replaced as a whole. AnSTM32 microcontroller was used as the master control unit in the system. A PCB-integrated sensor system was selected to detect the temperature, humidity, CO2, H2S, NH3, and dust concentration in the environment. Three standard conditions were set for the detection. Specifically, when the livestock or poultry felt uncomfortable, their behavior appeared too quiet or too irritable. When the livestock or poultry was sick, their body temperature was abnormal. When an infection occurred, the surface of the skin was ulcerated. A camera with a high-speed image transmission and a remote infrared temperature measurement device was used to monitor the livestock and poultry, where the abnormal state of their body temperature was observed in time, and the infection was found at an early stage. Two monitor sensors were installed on an electromechanical actuator, which was fixed on an electromechanical indexing plate in the front of the mobile platform. The actuator was used to adjust the pitch angle, whereas, the indexing plate was used to change the horizontal angle. An Ultra-Wide Band(UWB) wireless system was also selected to accurately locate the position of the mobile platform. All the data was sent to the STM32 microcontroller in UART, IIC, or analog output mode. The STM32 microcontroller processed the data with the Savitzky-Golay filtering, and then uploaded the data to the Ali Cloud IoT platform through a WIFI module. The users can login to the web page to remotely access the data, and thereby monitor the status of livestock and poultry in real time. The experimental results show that the detection data of a mobile intelligent detection platform was similar to that of the sensors in the former pig farm, where the relative difference between them was less than 10%. The positioning error was close to the 10 cm level, when the base stations were located at the optimal position. The monitoring data were reliable, and the mobile intelligent monitoring platform ran stably for a long time. The mobile platform can also serve as a carrier to transport about 200 kg of heavy objects. For instance, materials and livestock can be transported by the platform, when installing an upper cover plate with a winch and inclined plane on the surface. The proposed mobile intelligent monitoring platform can provide a hardware foundation for whole-scale environmental monitoring of livestock and poultry farms. [ABSTRACT FROM AUTHOR]

To study the electric actuator, a model is established with backlash nonlinearity and equivalent rigidity considered. Applying the describing function, the limit cycle of the actuator system is analyzed, and the characteristics of the limit cycle's frequency and amplitude are also analyzed. A method adding negative feedback moment to the load is proposed. The feedback moment can suppress the limit cycle of the actuator by changing the motion state of the load. The effect of the feedback moment to the servo system is analyzed and the principle of the feedback coefficient is given. The simulation results show the effectiveness of the describing function in predicting the limit cycle in the nonlinear system, and the proposed method does not affect the servo performance of the system and the negative feedback moment is valid in suppressing the limit cycle of the electric actuator with the backlash nonlinearity. [ABSTRACT FROM AUTHOR]

Fault-tolerant machines have attracted extensive attention in the field of machines all over the world for their high reliability, strong fault tolerance and strong ability for operation in harsh environments, therefore, deep researches are carried out focusing on their working principles, topologies, electromagnetic properties and control strategies. It can be found that this type of machine is very suitable for all-electric/moreelectric aircraft electrical actuator systems. This paper analyzes and summarizes the key technologies of faulttolerant machines for electrical actuator system from two aspects：Topology and control strategy. In terms of topology, the effects of each prototype machine on the original electromagnetic performance after introducing fault-tolerant design are compared, and the general design method and general law of fault-tolerant design of the machine are summarized. In terms of control strategy, the inside relations, advantages and disadvantages of two methods based on current vector reconstruction and voltage vector reconstruction are analyzed, furthermore, the torque impulse balance control of fault-tolerant machine for the speed performance improvement is investigated. The simulation and experimental verification are carried out for the classical topology and fault-tolerant algorithm. This paper summarizes the research prospect and application development of fault-tolerant machines, which offers references for the theoretical research and industrial application of fault-tolerant machines. [ABSTRACT FROM AUTHOR]

In order to reduce the air consumption of air-jet loom, a high frequency jet valve based on piezoelectric ceramics was designed. The dynamic characteristics of jet valve piezoolectric actuator were analyzed, the electromechanical coupling model of piezoelectric actuator was established. Matlab was used to analyze the system in time ancl frequency domain. The effect of numerical changes of different parameters on the dynamic characteristics and amplitude of the system was analyzed. The simulation data and test results are compared to verify the effectiveness of the system model. The simulation results show that the damping ratio of the system model is set to 0.71, the equivalent mass is 0.12 kg, and the load stiffness is taken 3 N/µm. the system has good dynamic characteristics and displacement output, which greatly reduces the useless air consumption of air-jet loom. [ABSTRACT FROM AUTHOR]

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Flow rate and pressure are two important control parameters of the irrigation system and they determine if the irrigation process can meet the irrigation demand or not. In the same pipeline system, flow rate and pressure affect each other, and it is difficult to control them separately. This study explored the relationship between flow rate and pressure and their control parameters, established a control technology suitable for the head of water distribution of the multi-user irrigation system. By analyzing the water supply characteristic curve of the pipeline water supply system, a flow pressure coupling adjustment method was proposed. This method allowed system controller output voltage analog and current analog to control the frequency of the inverter and the valve opening of the electric valve. At the same time, a proportion integration differentiation (PID) controller was used to realize the coupling control of the flow rate and the pressure. In addition, a method that use generalized regression neural network (GRNN) to accelerate the speed of PID (GRNN_PID) was proposed in order to speed up the response of irrigation control system, improve the operating efficiency and ensure the safety of the system. The flow, pressure and corresponding control quantities data were obtained through experiments, and the GRNN method was used to fit the relationship between them. Afterwards, the control quantities required for the target flow and pressure were quickly calculated by the fitting model and were used directly to control the corresponding actuator (pump and electric valve) so as to fine-tune the flow and pressure through PID. The GRNN training results showed that the relative error of the analog quantity used to control the frequency of the frequency converter was between 0.11% and 3.86%, and the relative error of the analog quantity used to control the electric valve was between 0.09% and 5.74%, indicating that the GRNN model has a high fitting accuracy. Three adjustment processes was used to simulate the water demand behavior of three users to verify the control model, and the tests showed that the adjustment times of the three processes of the GRNN_PID model were 11.6, 10.7 and 7.2 s, respectively, and the adjustment times of the three processes of the PID model were 31.7, 29.6 and 16.9 s, respectively. The GRNN_PID model greatly reduced the adjustment time of the system and improved the operating efficiency of the system. The control accuracies of GRNN_PID and traditional PID adjustment method were compared, and the results showed that the steady-state error of the GRNN_PID adjustment method and the traditional PID adjustment method were both within 1%, and the maximum overshoot was below 8%, which means that the control accuracy is high but the difference is not very big. The reason that leads to this result above is that GRNN accelerates the system regulation speed from the strategy, and it does not change the parameters of PID, and thus it has little impact on the control accuracy of the system. This research can provide tools for the rapid control of flow and pressure in irrigation system. [ABSTRACT FROM AUTHOR]

Copyright of Piezoelectrics & Acoustooptics is the property of Piezoelectric & Acoustooptic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)