Search

This study's aim is to control the proportional valves for automated drilling to serve as a preliminary phase toward the fully automated control of drilling rigs. Drilling rigs are quintessential in civil engineering and resource exploration, used primarily to bore holes into the ground. With the burgeoning demand for precision and smart functionalities in their operations, this research adopts a targeted approach. Central to the methodology, this study crafted a control module focusing explicitly on the three pivotal mechanisms of the drilling rig: impact, feed, and rotation. The optimal pressures essential for each control variable were determined through an in-depth study of the drilling patterns showcased by expert operators. These evaluations showed that an excessive feed pressure might distort the guide shell and bit, resulting in pronounced deviations in the drilling angle and compromised accuracy. Further intricacies were observed at the onset of rotation and feed, where a transient pressure surge emerged, which was attributed to the initial movement of a rod from its resting position. With these nuances in the foreground, an automated drilling algorithm tailored to maintain these optimal pressure thresholds was engineered. These research endeavors will pivot toward predicting the rock properties to fine-tune the pressure distribution in drilling rig control. This progressive approach to automation promises enhanced precision in drilling and sets a foundation for advanced research in drilling rig automation. [ABSTRACT FROM AUTHOR]

Considering the complexity and difficulty of obtaining certain parameters in the electro-hydraulic proportional control system, a precise transfer function of the system was derived through parameter identification using experimental data obtained from an Amesim simulation model after establishing a basic mathematical model. This approach reduces the reliance on accurate parameters of individual components. A feedforward-feedback composite controller was designed, and its effectiveness was validated in Simulink using the system's transfer function. Subsequently, the dead zone range of the proportional valve was determined through experiments, and a dead zone compensation strategy was designed, which reduced the time required for the proportional valve to traverse the dead zone by 89.4%. Based on the dead zone compensation, trajectory tracking experiments were conducted to validate the effectiveness of the feedforward-feedback composite controller. Under fixed disturbances, the trajectory tracking error was reduced by 53.8% compared to feedback control. Under time-varying load disturbances, the trajectory tracking error was reduced by 51.2% compared to feedback control. [ABSTRACT FROM AUTHOR]

This work introduces an algorithm integrated from two component signals called fuzzy sliding mode control (FSMC). This aims to ensure both road holding and ride comfort criteria rather than just one, as mentioned in previous articles. These mentioned criteria are guaranteed based on the design of membership functions and fuzzy rules, while the stability of the sliding mode framework is evaluated through the Lyapunov function. Simulations are performed in the MATLAB-Simulink interface, with four cases corresponding to different road types. According to the calculation results, the displacement and acceleration values of the sprung mass are the smallest once the FSMC method is used to control automotive suspension. In the last case, the wheel can be separated from the road if the automobile has only a passive suspension system or an active suspension system controlled by the proportional integral derivative (PID) algorithm. However, this does not happen when the FSMC algorithm is applied. As a result, the vehicle's road holding and ride comfort can be ensured in many conditions. [ABSTRACT FROM AUTHOR]

This study proposes and validates a novel combustion control system for oil-fired boilers aimed at reducing air pollutant emissions through flame image prediction. The proposed system is easily applicable to existing ships. Traditional proportional combustion control systems supply fuel and air at fixed ratios according to the set steam load, without considering the emission of air pollutants. To address this, a stable and immediate control system is proposed, which adjusts the air supply to modify the combustion state. The combustion control system utilizes oxygen concentration predictions from flame images via SEF+SVM as control inputs and applies internal model control (IMC)-based proportional-integral (PI) control for real-time combustion control. Due to the complexity of modeling the image-based system, IMC filter constant tuning through experimentation is essential for achieving effective control performance. Experimental results showed that optimal control performance was achieved when the filter constant λ was set to 1.5. In this scenario, the peak overshoot M p was reduced to 0.19245, and the Integral of Squared Error (ISE) was minimized to 10.1159, ensuring a stable response with minimal oscillation and maintaining a fast response speed. The results demonstrate the potential of the proposed system to improve combustion efficiency and reduce emissions of air pollutants. This study provides a feasible and effective solution for enhancing the environmental performance of marine oil-fired boilers. Given its ease of application to existing ships, it is expected to contribute to sustainable air pollution reduction across the maritime environment. [ABSTRACT FROM AUTHOR]

One of the challenges in precision livestock farming is controlling the variables that affect production and automation for actuator triggering. Automated systems with fuzzy logic allow the integration of expert knowledge from various contexts, facilitating the adoption of animal welfare practices. The objective of this study was to compare a fuzzy logic-based system model with a proportional control-based system model for regulating environmental conditions in pig pens. Through input variables such as temperature, relative air humidity and ammonia levels, the system output was the activation of fans/extractors and the opening/closing of curtains. MATLAB® software was used to model the systems and simulate actions to promote animal welfare. When comparing the efficiency of the fuzzy logic-based system with the proportional control system, it was observed that the output result of the fuzzy model was faster in 90.1% of the samples, with its average output in rpm being 12.7% higher than the proportional control system. The proposed fuzzy logic control system demonstrates efficiency for use in precision livestock farming processes. [ABSTRACT FROM AUTHOR]

The rapid and accurate control of air chamber pressure in slurry pressure balance (SPB) shield tunneling machines is crucial for establishing the balance between slurry pressure and soil and water pressure, ensuring the stability of the support face. A novel air chamber pressure control method based on nonlinear adaptive robust control (ARC) and using a pneumatic proportional three-way pressure-reducing valve is proposed in this paper. Firstly, an electric proportional control system for the air chamber pressure is developed. Secondly, a nonlinear state space model for the air chamber pressure regulation process is established. Utilizing experimental data from the SPB shield tunneling machine test bench, nonlinear adaptive identification is conducted through the nonlinear recursive least square algorithm. The results demonstrate the model's effectiveness and accuracy. Then, a nonlinear ARC for air chamber pressure is designed based on the backstepping method, and its Lyapunov stability is proved. Finally, the feasibility and effectiveness of the controller designed in this paper is verified through simulation and experiments. The results demonstrate that the developed control system can compensate for the nonlinearity and disturbance in the air chamber pressure regulation process. It can achieve good transient and steady-state performance and has good robustness against uncertainty. [ABSTRACT FROM AUTHOR]

The paper presents a detailed analysis of control and observation of generalized Caputo proportional fractional time-invariant linear systems. The focus is on identifying controllable states and observable systems within the controllable subspace, null space, and unobservable subspace of the proposed system. The necessary conditions for the controllable subspace and the necessary and sufficient conditions for observability criteria are firmly established. The controllable subspace is treated geometrically as the set of controllable states, while the observable system is characterized by a zero unobservable subspace. The results are reinforced by examples and will immensely benefit future studies on fractional-order control systems. [ABSTRACT FROM AUTHOR]

An active elastic metasurface has more flexibility than a passively modulated elastic metasurface, owing to the manipulation of the phase gradient that can be realized without changing the geometrical configuration. In this study, a negative proportional feedback control system was employed to provide positive active control stiffness for adaptive unit cells, with the aim of achieving the active modulation of the phase gradient. The relationship between the control gain and the phase velocity of the flexural wave was derived, and the transfer coefficients and phase shifts of the flexural wave through the adaptive unit cells were resolved using the transfer matrix method. Finite element simulations for wave propagations in the adaptive unit cells were conducted, and they verified the analytic solutions. Based on this theoretical and numerical work, we designed active elastic metasurfaces with adaptive unit cells with sub-wavelength thicknesses according to the generalized Snell's law. These metasurfaces show flexibility in achieving abnormal functions for transmitted waves, including negative refraction and wave focusing, and transforming guided waves at different operating frequencies by manipulating the control gain. Therefore, the proposed active metasurface has great potential in the fields of the tunable manipulation of elastic waves and the design of smart devices. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Measurement Science & Instrumentation is the property of Journal of Measurement Science & Instrumentation 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.)

Energy storage systems (ESS) and permanent magnet synchronous generators (PMSG) are speculated to be able to exhibit frequency regulation capabilities by adding differential and proportional control loops with different control objectives. The available PMSG kinetic energy and charging/discharging capacities of the ESS were restricted. To improve the inertia response and frequency control capability, we propose a short-term frequency support strategy for the ESS and PMSG. To this end, the weights were embedded in the control loops to adjust the participation of the differential and proportional controls based on the system frequency excursion. The effectiveness of the proposed control strategy was verified using PSCAD/EMTDC. The simulations revealed that the proposed strategy could improve the maximum rate of change of the frequency nadir and maximum frequency excursion. Therefore, it provides a promising solution of ancillary services for frequency regulation of PMSG and ESS. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Henan University of Science & Technology, Natural Science is the property of Editorial Office of Journal of Henan University of Science & 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 Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) 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.)

In this paper, we compare two different kinds of position controllers, namely PD (both compensated and uncompensated PD) and Cascade controller (both compensated and uncompensated Cascade). SIMULINK software is used to implement lumped parameters estimation with UKF. The Proportional-Derivative (PD) controller design by root locus and Cascade controller design have been chosen for our feedback system, and coulomb friction as disturbance is taken into account in the estimation model. The aim of this paper is to find out which controller is better (both compensated and uncompensated PD controller vs. both compensated and uncompensated Cascade controller). Therefore, the objective is to show how useful the parameter estimation for controller design with compensation. Through comparing two position controller designs, the experiment results show that both Compensated Proportional Derivative (PD) controller and Cascade controller Design have much better performance than the Uncompensated ones. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) 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 Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) 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.)

The intellectual history of energy homeostasis, focusing on food intake and energy storage, is briefly reviewed. Physiological energetics was founded by Lavoisier, who in the late eighteenth century invented direct and indirect calorimetry and discovered the role of oxygen in combustion and respiration. Energy was understood well enough by the mid-nineteenth century to realize the physiological energy-balance equation, that energy intake – energy expenditure = energy storage, but this did not greatly influence physiological research for another century. Homeostasis, the concept that many vital physiological variables are actively regulated in narrow envelopes, was developed by Bernard and Cannon between approximately 1870–1940 and remains a central principle of physiology. Kennedy coined the term lipostasis in 1953 to refer to the constancy of fat mass, which Mayer argued was the mechanism regulating body weight. A parameterized control-theory model suggests that a proportional negative-feedback control system incompletely compensates weight loss during persistent negative energy balance, suggesting that Cannon's idea of constancy within a narrow envelope may not fit body-weight regulation well. This modelling encourages further application of control theory to issues in energy homeostasis, including to the development of obesity. It also sets the stage for understanding the underlying neuroendocrine mechanisms. This article is part of a discussion meeting issue 'Causes of obesity: theories, conjectures and evidence (Part I)'. [ABSTRACT FROM AUTHOR]

Pneumatic motors have several advantages and have many robotics and automation applications. The importance of the study is that it is a cheap and possible way to apply it to the fixed displacement pneumatic motors with simple directional control valve used. The purpose of the addition to any traditional pneumatic motors is to change the fixed displacement pneumatic motor to be variable speed and torque compared to the expensive systems such as the proportional control valve in many industrial applications. The study also included validated simulations using the Automation Studio program to control the pneumatic motor's speed and torque. In addition, the results showed remarkable success in controlling the pneumatic motor outputs depending on the frequency of the compressed air-source pulses and pressure. The pulsating air frequencies of 1.5, 3, and 4.5 Hz were considered at different inlet source pressure changes from 1.72, 3.45, and 5.17 bar. As the pulsating flow frequency of compressed air decreased from 4.5, 3, and 1.5 Hz, the motor pressure and torque decreased. Furthermore, empirical correlations related to frequency and pressure effect have been developed. The error is 6.3–9.5% in predicting the motor speed and torque outputs. The limitation of the proposed method in real-life applications is about a maximum of 7.5 bar. On the other hand, the frequency is limited to 9 Hz using a mechanical solenoid. [ABSTRACT FROM AUTHOR]

Copyright of Low-Carbon Chemistry & Chemical Engineering is the property of Low-Carbon Chemistry & Chemical Engineering Editorial Office 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.)

Nominal Characteristic Trajectory Following (NCTF) system is a simple control system. This control system comprises a Nominal Characteristic Trajectory (NCT) and a compensator. The practical aspect of an NCTF control system is obtained by manufacturing controllers based on simple open-loop experiments. Arduino Uno is used as the system controller. The study has been conducted to obtain the best type of NCT based on the NCTF proportional integral applied by the one mass of the vertical eccentric rotary system. MATLAB® software commands Arduino Uno to drive the motor and read the encoder. The system's performance can be seen by conducting tests on various types of NCT, by using variations of the angular destination position with 0.01-second sampling time. The variations of angular destination position consist of 0.785, 1.57, and 2.355 radians. Information on steady-state error, settling time, and overshoot would be analyzed to determine the best recording method of the NCT for one mass vertical eccentric rotation mechanism and the system's robustness. The results have showed that the NCTF control system based on proportional integral has performed best when using the NCT unload recorded type. This system has become a robust control system with a maximum value of steadystate error of 0.93%. The best response speed is determined by the smaller settling time value with a maximum time of 2 s. However, the overshoot is still emerging during the experiment as the typical reaction from the inertia moment of the imposition. Based on this research, it can be concluded that it is possible to use Arduino Uno as a DC motor controller on an eccentric arm with an NCTF system. [ABSTRACT FROM AUTHOR]

The issue of position/force control of collaborative robotic systems moving a payload is proposed in this paper. The proposed approach must be able to maintain the orientation/position of the payload on the reference trajectory while applying a limited force to the object through the robot's endeffector. With this in mind, linear/nonlinear PID control schemes have been proposed to achieve accurate and robust tracking performance. Lyapunov's stability analysis is utilized to confirm the stability of the controlled system. It proves that the controlled system is stable, while the object's orientation/position tracking errors are uniformly ultimately bounded (UUB) in any bounded region of state space. It also presents some conditions for proper selection of the linear/nonlinear PID controllers' gains in the form of two theorems. The proposed controllers apply to two coordinated 3DOF robotic arms that carry a payload. The simulation results tested two types of trajectories, including simple and complex paths. The results are also compared to those of a strong state-of-the-art approximator, the Chebyshev Neural Network (CNN). [ABSTRACT FROM AUTHOR]

• Snap-through phenomenon is shallow spherical shells made of FGM is investigated. • An active control strategy using sensor/actuator layers is proposed. • Critical buckling pressure of the spherical shell may be delayed using appropriate gain factors. • Budiansky criterion is used to distinguish the buckling pressure of the shell. The mechanical snap-through phenomenon represents one of the buckling modes inherent in shallow shells, exemplifying the shell's reaction to external loads, which can potentially have detrimental effects on structural performance. This article delves into the study of this phenomenon within the context of spherical shells. Leveraging functionally graded material (FGM) in the main layer of this structure proves instrumental in enhancing the shell's performance against rapid mechanical loads. Furthermore, the strategic placement of piezoelectric layers, both symmetrically and asymmetrically, coupled with the implementation of a proportional and derivative control system, facilitates the control of the shell's response. The formulation of displacement field and electric potential is grounded in the first-order shear deformation theory (FSDT) and second-order distribution, respectively. The strong form of nonlinear dynamic and electrostatic equations is derived using Hamilton's principle. Solving these equations is achieved through the implementation of the generalized differential quadrature (GDQ) method in the spatial domain and Newmark in the time domain. Additionally, the Newton-Raphson method is employed to tackle the inherent nonlinearity of the problem. The Budiansky's criterion is employed for the assessment of the load necessary for the buckling of the shell. Following the validation of results against numerical, analytical, and laboratory outcomes, a set of parametric results is presented. These results underscore the remarkable impact of the control system in mitigating shell deformation under time-dependent mechanical loads, as well as in postponing the occurrence of the snap-through phenomenon and damping the vibrations. [ABSTRACT FROM AUTHOR]

Copyright of Journal of South China University of Technology (Natural Science Edition) is the property of South China 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.)

This paper addresses a design optimization of a gas turbine (GT) for marine applications. A gain-scheduling method incorporating a meta-heuristic optimization is proposed to optimize a thermodynamics-based model of a small GT engine. A comprehensive control system consisting of a proportional integral (PI) controller with additional proportional gains, gain scheduling, and a min-max controller is developed. The modeling of gains as a function of plant variables is presented. Meta-heuristic optimizations, namely a genetic algorithm (GA) and a whale optimization algorithm (WOA), are applied to optimize the designed control system. The results show that the WOA has better performance than that of the GA, where the WOA exhibits the minimum fitness value. Compared to the unoptimized gain, the time to reach the target of the power lever angle is significantly reduced. Optimal gain scheduling shows a stable response compared with a fixed gain, which can have oscillation effects as a controller responds. An effect of using bioethanol as a fuel has been observed. It shows that for the same input parameters of the GT dynamics model, the fuel flow increases significantly, as compared with diesel fuel, because of its low bioethanol heating value. Thus, a significant increase occurs only at the gain that depends on the fuel flow. [ABSTRACT FROM AUTHOR]

This paper presents the design of a control strategy based on the active rejection of disturbances, applied to the temperature regulation of a crucible furnace for the aluminum smelting process. For this purpose, the generalized proportional integral control was used, which was designed based on the simplified model of the furnace identified by means of the Matlab PIDtuner app. When applying the designed control to the model, follow-up data were taken from the reference signal and analyzed using the percentage of quadratic error measured. This showed that the generalized integral proportional control applied to the system model obtained a mean square error percentage of 0.433%, and with a 50% variation of the model parameters the mean square error percentage was 2.88%. [ABSTRACT FROM AUTHOR]

The paper deals with an electrical design of an electrohydraulic system, which is capable to use for rock pressing. The system has three stations, which controlled by programmable logic controller. The electrical design contains the wiring, and the development of a valve controller card, which provides adequate current to a pressure relief valve. [ABSTRACT FROM AUTHOR]

Today's power distribution networks are predicted to incorporate more Power Electronics (PE)-based power conversion systems, widely acknowledged as harmonic sources. Concerns about power harmonic severity in the distribution networks can arise, especially with the growing numbers of Medium Voltage Direct Current (MVDC) systems, which are also facilitated by such power converters. Yet, an accurate harmonic model of the MVDC converter is required to investigate its harmonic emissions, propagations, effects, and solutions in today's distribution networks. This article is devoted to the development of a detailed model of a cascaded Neutral Point-Clamped (NPC)-based MVDC converter for accurate harmonic analysis studies. An appropriate control system with a simple Proportional Integral (PI) controller tuned using the loop-shaping technique is developed. An interleaved Sinusoidal Pulse-Width Modulation (SPWM) scheme aiming to improve the harmonic performance of such an application is introduced. The detailed model of the MVDC system was developed using the Simulink/MATLAB simulation environment, for which the concept of operation was validated, control system performance was investigated, and the effectiveness of the harmonic reduction method was analysed. The key finding is that the interleaved SPWM technique has significantly reduced the Total Harmonic Distortion (THD) to 2% with no significant even-order harmonic components in comparison to the reported models. [ABSTRACT FROM AUTHOR]

Summary: The grid is a platform of distributing the power to the consumers; if an automatic controlling and monitoring are connected with the grid, it referred to as smart grid (SG). Self‐healing is the approach of restoring the unaffected areas without affecting the system performance. The term restoration is if a fault occurs on a distribution system, it must be isolated; after that, it can be reconfigured to restore the unaffected areas. The distribution system cannot work as efficient without the self‐healing approach because it will affect the unaffected areas without any proper reason. This paper proposed a multiagent system with controlled voltage (MAS‐CV) along with self‐healing of wireless sensor network (WSN) with proportional integral derivative (PID) controller in smart grid. At initial, the magnetic flux sensors are placed in the pole transformer for detection of flux leakage. The sensed data are transferred to the distribution grid, where the multiagent system (MAS) is established to carrying out the load restoration process (i.e., self‐healing). Connection agents (CA), monitor agent (MA), main feeder agent (MFA), backup feeder agent (BFA), supporting feeder agent (SFA), and local agent (LA) are the agents presented in the paper. Each agent is communicating via agent communication language (ACL) for the restoration process; after all the loads are restored, the voltage drop of the system is controlled by the proportional integral derivative controller. The simulation results of the proposed method show that the restoration of loads is improved and number of switching is reduced with improved data transmission. Thus, the cost of the proposed method is reduced by the reduced switches. At last, the controlled power from the distribution grid is send to the consumer. [ABSTRACT FROM AUTHOR]

This article proposes an efficient thermoelectric temperature control system based on an improved proportional integral differential (PID) algorithm in which energy feedback technology is used to enhance thermoelectric cooling. In the proposed power management system, two groups of batteries are efficiently and alternatingly charged and discharged such that the information of the circuit can be monitored in real time. The PID algorithm is improved by using the idea of a state machine to control the thermoelectric coolers (TEC) through an H-bridge circuit with pulsewidth modulation. Finally, the energy feedback circuit combined with improved synchronous switching technology is designed to recycle the energy to drive the sensor. By inputting current of 3.1 A, a wide range of temperature control from 1.437 to 60.187 °C was implemented. While targeting a temperature of 10 °C at an ambient temperature of 22 °C, the proposed temperature control system had a control time of 30.5 s, compared with 287 s when using the conventional method, with an accuracy of 0.1 °C, and an error of only ±0.35 °C. The results confirm that electric energy at a peak voltage of 1.2 V and current of 24 μA can be recovered. The proposed energy feedback system can thus improve the efficiency of energy utilization of TEC from a peripheral circuit. [ABSTRACT FROM AUTHOR]

The article presents the influence of oil viscosity on the overall efficiency of the compared systems with proportional cylinder control. There are energy losses in the elements of the hydraulic system, which are, among other things, a function of the viscosity of the working fluid used, as well as energy losses which are practically independent of the viscosity. In order to assess the possibilities of saving energy during the operation of the hydrostatic drive system, it is necessary to understand and describe the losses occurring in the system. Determining the energy efficiency of the system can be performed simulation with the help of a computer program using an appropriate mathematical model. The efficiency determined in this way can be used in the process of designing and operating the system. [ABSTRACT FROM AUTHOR]

The article focuses on proportional-integral-derivative (PID) controllers can handle most control problems if properly tuned. Topics include the good process control relies on proper controller tuning, the basics of proportional-integral-derivative (PID) control and outlines two methods for tuning live systems without the need for tuning formulas or knowledge of equipment characteristics, and the process itself provides the feedback information needed for proper control.

The article focuses on control systems can be direct-acting or reverse-acting in a direct-acting system, an increase in the OP causes an increase in the PV. Topics include the valve opening (OP) would cause the temperature (PV) to decrease and it would be a reverse-acting system, and the type of controller action is an important factor in the control equations.

The active magnetic bearings system plays a vital role in high-speed rotors technology, where many research articles have discussed the nonlinear dynamics of different categories of this system such as the four-pole, six-pole, eight-pole, and sixteen-pole systems. Although the twelve-pole system has many advantages over the eight-pole one (such as a negligible cross-coupling effect, low power consumption, better suspension behaviors, and high dynamic stiffness), the twelve-pole system oscillatory behaviors have not been studied before. Therefore, this article is assigned to explore the effect of the magneto-electro-mechanical nonlinearities on the oscillatory motion of the twelve-pole system controlled via a proportional derivative controller for the first time. The normalized equations of motion that govern the system vibrations are established by means of classical mechanics. Then, the averaging equations are extracted utilizing the asymptotic analysis. The influence of all system parameters on the steady-state oscillation amplitudes is explored. Stability charts in a two-dimensional space are constructed. The stable margin of both the system and control parameters is determined. The obtained investigations reveal that proportional gain plays a dominant role in reshaping the dynamics and motion bifurcation of the twelve-pole systems. In addition, it is found that stability charts of the system can be controlled by simply utilizing both the proportional and derivative gains. Moreover, the numerical simulations showed that the twelve-poles system can exhibit both quasiperiodic and chaotic oscillations besides the periodic motion depending on the control parameters' magnitude. [ABSTRACT FROM AUTHOR]

Variable rate fertilization has generally been implemented in the field traction liquid fertilizer applicator under a variety of soil and tillage conditions in recent years. However, it is very necessary to improve the precision, even fertilization, and fertilizer saving during operation in modern mechanized agriculture. In this research, a novel fuzzy PID control was proposed using genetic algorithm (GA) for the variable rate fertilization control system of liquid fertilizer. Firstly, a closed-loop negative feedback model was established for the control system of liquid fertilizer variable rate fertilization, thereby to obtain the transfer function Gr(s) of control process. The control process was also optimized, according to the structure of traction variable liquid fertilizer applicator and the composition of electrical components. Among them, the control object was mainly an electric proportional valve in the control system. The feedback channel was read by the flow meter, and then transferred the electric signal to the controller. Specifically, the controller was implemented to compare the flow reading with the vehicle speed and the amount of fertilizer required for the current field. The obtained data was converted into the control signal, and then output to the electric proportional valve, so as to realize the negative feedback control of system. Some models were established for the traditional, fuzzy, and GA-based fuzzy PID control, according to the requirements of control system. Particularly, the fuzzy PID control model was first established before the GA-based fuzzy PID control model. The input quantity of fuzzy controller was set as the error and the error rate of change, while the output quantity was set as the compensation value of three parameters in the PID controller, where each input and output quantity was set to 7 fuzzy language values. Therefore, there were 49 fuzzy control rules in total. Subsequently, the fuzzy control rules were chromosome-coded within GA. The chromosomes of fuzzy control rules were then simulated and optimized to obtain the optimal fuzzy control rule table using genetic operators, such as selection, crossover, mutation. Correspondingly, the fuzzy PID controller was further set, according to the optimal fuzzy control rules. Finally, MATLAB software was also selected to simulate the traditional, fuzzy, and GA-based fuzzy PID control. Consequently, the response time of electric proportional valve control was 4.86 s for the variable rate fertilization control system using the GA-based fuzzy PID control, which was significantly shorter than the 8.4 s of the traditional PID control, and the fuzzy PID control of 7.32 s. An experimental platform was constructed to carry out the stability and variable control experiment for the flow control in the control system of liquid fertilizer variable rate fertilization. In addition, the flow error was measured during operation in the fertilization stability experiment. The average relative errors of control system were 5.01%, 3.41%, and 1.24%, respectively, corresponding to traditional PID control, fuzzy and GA-base fuzzy PID control during stable operation. The signal was collected and recorded for the actual vehicle speed change in the variable control experiment. The inputs were the collected vehicle speed signal to the controller through a signal generator, thereby to measure the flow when the vehicle speed changed. Consequently, the actual response times were 5.19, 4.12, and 3.21 s, respectively, corresponding to the three control modes. More importantly, the GA-based and fuzzy PID control reduced the average relative error of 3.77% and 2.17%, respectively, compared with traditional, when controlling the flow of variable rate fertilization control system. Additionally, the actual response time of GA-based and fuzzy PID reduced by 1.98 and 0.91s, compared with the traditional PID control. Anyway, the GA-based fuzzy PID control presented better response time to flow control in the variable rate fertilization control system than traditional and fuzzy PID control, indicating better operational stability. [ABSTRACT FROM AUTHOR]

In order to improve the shift quality of automatic transmission with synchroniser, a synchroniser electrohydraulic control system equipped with the proportional pressure reducing valves is proposed. The principle of the control system is introduced in detail. The PID controller is used to realise closed-loop control of shift displacement to achieve the synchronisation. A numerical model and a test apparatus have built up to validated the control performance. The simulated and measured engagement and disengagement of the synchroniser with the proposed control system are investigated in detail. The results indicate that the shift displacement is controllable by changing the cylinder chamber pressure. The back pressure value is useful for a smooth synchroniser operation. It is determined by the sleeve motion and the throttle parameter. The back pressure affects little on the synchronisation stage during the engagement process. The proposed method can be used for the optimising design of the electrohydraulic system for the synchroniser control. [ABSTRACT FROM AUTHOR]

Overuse of chemical fertilizers is one of the important factors that cause the agricultural nonpoint source pollution to aggravate in precise agriculture. The middle and lower reaches of the Yangtze River are the main producing areas of oilseed rape in China. In sowing, the mixed and extensive application of chemical fertilizers with low utilization has become a severe restriction on the sustainable production of rape in green agriculture. Layered and quantitative fertilization is an alternative way to reduce the excessive amount, while increasing the efficiency of chemical fertilizers. In layered fertilizing, the proportion of fertilizers in the upper and lower layer can be accurately controlled with a high utilization rate for the later advantageous growth of crops in different areas. However, the traditional extensive mode of operation has posed a great challenge on the direct seeding of rapeseed in the middle and lower reaches of the Yangtze River. In this study, a layered and proportional fertilizing device was proposed for the uniform distribution of fertilizer flow in a rape seeder, according to the planting and growth pattern of the root system. A proportional control system was applied to adjust the amount of fertilizer in the upper and lower layers, while separately fertilizing at the left and right of the upper layer. A quadratic regression orthogonal test was conducted to take the diameter of blocking rod, the number of the blocking rod groups, and the distance between blocking rods as the experimental factors. The optimal structural parameters of the device were determined: the rod diameter was 3 mm, the number of rod groups was 5, and the distance between the rods was 8.9 mm. A performance test of fertilizer discharge was carried out under the optimal combination of parameters. The evaluation indexes were set as the error between the target fertilizing ratio and the actual fertilizing ratio, the variation coefficient of stable discharge volume for the upper and lower pipes, and the variation coefficient of stable discharge volume for the left and right sides of the upper pipe. The test results showed that the maximum error between the actual and target fertilizing ratio was 4.1 percentage points for the upper and lower layers, indicating very little influence on the later growth of rape. The variation coefficient of stable fertilizer discharge in the upper and lower layers was lower than 3.9%, indicating a stable distribution of fertilizer ratio for the standard requirements in the layered fertilization of rape. The error between the actual and target fertilizing ratio was less than 4.1 percentage points in the upper pipe, meaning an excellent fertilization effect for the standard requirements in the upper layer. The variation coefficient of stable discharge volume was lower than 4.8% in the upper pipe. There was no obvious relationship with the rotational speed of the discharge device, indicating excellent stability of discharge volume for the left and right sides. The field test showed that the fertilizing device was stable for the high requirements in the layered fertilization of rape. This finding can provide potential technical support for the proportional layering of fertilizer during large-scale production of oilseed rape. [ABSTRACT FROM AUTHOR]

The problem of designing conventional controllers is a major concern in both academia and industry. The paper presents the implementation of a Matlab interface that facilitates the students' understanding of the closed-loop control systems operation. There are four operating scenarios: with controllers for which the parameters are known; with controllers for which parameters are determined experimentally; with proportional controllers and additional poles/zeros introduction; with proportional controllers and serial compensator. [ABSTRACT FROM AUTHOR]

Standalone DC micro-grid requires highly efficient power converters with high performance robust controllers. This research work deals with the hardware implementation of a load side buck converter and its control system integrated in a DC micro-grid system. This paper presents a novel fractional order sliding mode control (FSMC) method for voltage regulation of a buck converter feeding a constant power load. FSMC controller is derived based on the average state space model of the buck converter and its stability is verified using Lyapunov theorem. Finally, the FSMC controller is implemented using Arduino mega 2560 processor and the obtained results are compared with classical sliding mode control (SMC), proportional, integral, derivative (PID) control and fractional order PID control system (FOPID under constant and variable resistive loading. [ABSTRACT FROM AUTHOR]

The objective of this paper is to design three different robust controllers such as proportional-integral (PI), internal model control (IMC), and H8 control techniques for position control of the computerized numeric controlled machine tool (CNCMT) system. The proposed controllers aim to control the servo motor that regulates the position of the machine table and also enhances the robustness of the CNCMT system under the influence of parametric uncertainties. The stability of the uncertain CNCMT system with all designed controllers is investigated using Kharitonov's theorem. The stability margin (SM) criterion is utilized for robustness analysis. [ABSTRACT FROM AUTHOR]

Purpose: The drive shaft and the distribution shaft of a traditional radial piston pump are in a cantilever state. To solve this problem, this paper aims to present a radial piston pump with through shaft driving and valve plate distribution. Design/methodology/approach: The working principle of the pump is discussed in detail. In this radial piston pump, valve plate distribution parts are designed to distribute oil to the piston chambers, and the distribution shaft is replaced. A bearing is installed between the stator and rotator to reduce the friction. The transmission shaft is supported by two bearings to ensure smooth operation. The support force of the transmission shaft is optimized. In addition, the flow pulsation principle is presented. To accomplish the change, the displacement of the radial piston pump, the proportional control system is designed. Findings: After completing the machining and assembly of the pump, an experimental study was carried out. The results show that the output flow of the pump is basically the same as the theoretical flow. Originality/value: The friction between the slipping shoes and the stator is greatly reduced due to the function of rolling bearings. The higher stability of the driveshaft is obtained for the reason of double-sided support. The radial piston pump has a novel structural design in reducing the friction between the shoes and the stator and improving the stability of the transmission shaft. [ABSTRACT FROM AUTHOR]