Independent Control System Research Articles

Design of a Conformal Ablation System Based on Independent Control of Radiofrequency Electrode Arrays

This study aims to develop an independent control system for radiofrequency electrode arrays, intended for the conformal ablation of unwanted tissues. Unlike traditional single radiofrequency voltage applications, this study employs high-frequency transformer isolation and radiofrequency load matching technologies to divide the radiofrequency signal source into eight independent groups. Each group operates at the same phase and frequency but with different voltage values. Experimental results indicate that the designed system can independently output various combinations of radiofrequency signals. The actual output voltage has a relative error controlled within 6%, the frequency error is less than 0.5%, and the phase difference among the groups is less than 1°. In the biomimetic tissue heating experiments, it is found that by controlling the voltage of each electrode within the electrode array, ablation of different shapes can be achieved, and the ablation depth is positively correlated with the applied radiofrequency voltage.

A fault detection and isolation method for independent metering control system based on adaptive robust observer

The independent metering control system (IMCS) demonstrates high control precision and energy efficiency for advanced electrohydraulic applications but tends to be faulty. Current model-based fault diagnosis methods face challenges in robustness and adaptability to high uncertainties and high nonlinearities of the IMCS. To enhance the safety and reliability of the IMCS, a novel fault detection and isolation method based on adaptive robust observer (ARO) is proposed. To reduce estimation errors, the designed ARO combines the advantages of the robust filter and parameter adaption, which can overcome the impact of uncertainties and nonlinearities. To detect the fault robustly and sensitively, three types of adaptive thresholds are designed according to the spool displacement residuals. To isolate the fault, a fault space is established, and spatial fault points are calculated. The verification experiments show that the proposed method can well estimate the spool displacement while accurately detecting and isolating faults of the IMCS.

Independent local environment control for visitor and relics area within site museums by displacement ventilation

The interior spaces of large-span site museums can typically be categorized into relic preservation areas, visitor corridors, and non-occupied spaces, with only the relic preservation areas and visitor corridors requiring environmental control. The conflicting needs of visitors and relics often render inefficiencies in simultaneously satisfying the thermal needs when using a sole environmental control system. To address this, an independent local environment control method that employs an air curtain to isolate the visitor corridor from the unoccupied space, along with displacement ventilation (DV) systems to regulate the local environment for the visitor corridor and relics, is proposed in this study. The effects of the supply air inlet and air curtain on the performance of the DV system and the feasibility of an independent local environmental control system were evaluated. The results indicated that the performance of the DV system in the visitor corridor was optimal when the height of the air inlet was 0.6 m. When both DV systems were operating, the mean temperature and relative humidity (RH) were 25.6 °C and 68.6 %, respectively, in the visitor corridor, and 20.6 °C and 95.3 %, respectively, in the relic preservation area; both visitor and relic requirements were met independently. This study provides a newly designed independent local environmental control system for museums.

A dynamic simulation study of temperature and humidity independent control system for temperate semi-humid continental monsoon climate regions

A temperature and humidity independent control (THIC) system is a promising solution for hot and humid indoor working environments. This study proposes a dual-source heat pump air-conditioning (DSHPAC) system composed of a dual-source heat pump (DSHP) and air handling unit (AHU) as a THIC system. The proposed THIC system indirectly adjusts the cooling capacity of the high-temperature evaporator (Eva1) and low-temperature evaporator (Eva2) by controlling the refrigerant mass flow rate of the system to meet the cooling and dehumidifying requirements under different operational conditions. The proposed THIC system can switch among three operational modes by using the designed operational strategy, ensuring that the requirements for indoor temperature and humidity are met. In addition, the mathematical model and equilibrium equations of the THIC system are established. This study uses an office building in Xi'an on a typical summer day as a simulation case in dynamic simulations. The coefficient of performance (COP), cooling capacity, and compressor power consumption of the proposed DSHP system are analyzed. The results demonstrate that the COP of the proposed system increases with the temperature of Eva1 (TEva1), the COP of the proposed system varies from 1.76 to 3.62, and the cooling capacity increases from 1.19 kW to 3.38 kW when TEva1 increases from 6.24 °C to 36.4 °C. The analysis of different values of φR (refrigerant mass ratio) shows that the highest COP is achieved at φR = 0.1. The results prove the application potential of the dual-source heat pumps to the THIC air-conditioning systems.

Comparative analysis of theoretical cycles of independent valve control systems of the SI engine

The objects of the study were theoretical cycles of the load control systems and charge exchange process in the naturally aspirated SI engine, including: classic, quantitative throttling control (Seiliger-Sabathe open cycle); system with late inlet valve closing LIVC (the Atkinson-Miller open cycle); system with early inlet valve closing EIVC; system with early exhaust valve closing EEVC, enabling internal exhaust gas recirculation; system of fully independent valve control FIVC. The aim of using camless independent valve control algorithms is to eliminate the throttle as an control valve for load and filling control of the SI engine, while retaining quantitative load control. The aim of the research is to select the camless valve control algorithm most beneficial in terms of energy (the highest effective efficiency) and economy (the lowest fuel consumption).

Study on the temperature rise characteristics of aging lithium-ion batteries under different cooling methods

Lithium-ion batteries have been widely used in electric vehicles and electrochemical energy storage power stations. With the increase of service time, the single cells in the battery module will age to varying degrees, resulting in inhomogeneous heat generation and even safety accidents. Considering that there is currently limited research on the cooling effect of battery cooling technology on aging batteries, this article adopts a new non-destructive method to study the uneven aging characteristics and the temperature rise characteristics under different cooling conditions of different cells in small aging lithium-ion battery modules. The results show that the irreversible heat generation power of cell 1, cell 2 and cell 3 during 1 C discharge is 1.23 W, 1.33 W and 1.15 W, respectively, showing different degrees of aging. However, the maximum temperature rise under natural heat dissipation conditions has the same change trend and the average temperature rise on the surface of three cells at the end of discharge is about 20 °C. The temperature rise at the edge of cell 2 and cell 1 with more serious aging is higher, while the temperature rise at the center of cell 3 with the smallest aging degree is higher. The temperature distribution at different positions on the surface of the three cells was slightly different. The maximum temperature difference at different positions on the surface of cell 2 (2.3 °C) was greater than that of cell 1 (1.5 °C) and cell 3 (1.6 °C). Then, a simple OCV test method and SEM characterization technique were used to analyze the aging characteristics of the electrode position corresponding to the external temperature monitoring position of cell 2, and the relationship between temperature distribution and aging characteristics was established. The cooling and uniform temperature ability of thermal pad, semiconductor cooling and liquid cooling plate/semiconductor composite cooling are improved in turn. Among them, the liquid cooling plate/semiconductor composite cooling is an efficient temperature control strategy which can make the temperature of cell 3 basically stable at 23 ° C during 1C discharge by reasonably regulating the cooling power, and the maximum surface temperature difference is maintained at 0.4 ° C. It is suggested that when the large cell is put into use, it should be equipped with an independent sub-regional precise temperature control system that can adjust the cooling power in real time according to the heat production rate of the battery, so as to improve the safety and promote the development of sustainable energy.

Optimal control of high-rise building structures against earthquake excitations using independent stories as TMD

In this paper, in order to control the behavior of tall building structures against vibrations caused by earthquakes, the parameters of a new passive control system named “independent story” are optimized. This control system is installed like a large tuned mass damper in the main story of the building. Moreover, in order to improve the performance of this control system, six liquid viscous dampers connected from the roof of an independent story to the main story of the building, have also been used to increase damping of the system. The main goal of the present research is to optimize the parameters of this system, including selecting the optimal story/stories of the building to install the independent story/stories, such that the maximum reduction in the mean values of the maximum displacement and maximum acceleration responses of different stories of the building can be obtained, simultaneously. To evaluate the performance of the proposed control system, as a numerical example, a 3-D model of a twelve-story steel building structure is selected for which three degrees of freedom in each story have been considered. Then, a deep search is conducted to find the story/stories of the building at which the independent story control system along with the related supplemental liquid viscous dampers can be constructed/installed such that the best performance of this control system in response reduction of the building can be obtained. Finally, the optimal values of the mass and damping of the supplemental dampers of this system are found to be about 6% of the total mass of the building, and 13 kN-sec/mm, respectively; and the eighth and twelfth stories of the building are the best places for implementation of the proposed control system. By applying the optimal values of all the design parameters of the IS control system, the mean values of the building roof story response reductions were obtained to be about: 28.60% and 26.67% reduction on maximum displacement responses in x and y directions, respectively; and those of the maximum acceleration responses as 43% and 48.89%.

Reinforcement learning-based demand response strategy for thermal energy storage air-conditioning system considering room temperature and humidity setpoints

Heating, ventilation, and air-conditioning systems significantly influence demand response (DR) actions. In the literature, many studies have investigated the reduction of sensible loads through DR events by increasing temperature setpoints while satisfying indoor comfort levels. However, less consideration has been given to latent loads. Therefore, proximal policy optimization reinforcement learning (RL) algorithms are adopted to simultaneously control indoor temperature and humidity (T&H) setpoints to reduce sensible and latent loads. An EnergyPlus-Python joint simulation platform was created for the temperature-humidity independent control system. DR strategies based on RL, active thermal energy storage, and time-of-use electricity prices are formulated to find the optimal indoor T&H setpoints, considering environmental constraints, comfort levels, and energy consumption. The results showed that in the optimal experimental strategies implemented based on negative feedback regulation, savings of 29.15 % on electricity consumption were achieved during DR periods and 46.11 % savings on the daily operating costs. Moreover, a simulation strategy based on feed-forward regulation was developed and found to reduce electricity consumption by 6.92 % during DR periods. Compared with a fixed T&H setpoint, the developed strategy meets the preferences of different groups of people for thermal comfort and increases the system's flexibility.

Methodology for Simultaneous Simulation of Convective And Radiative Heating

During the ascent flight of a Launch Vehicle (LV), certain regions are exposed to radiative and convective heating simultaneously. A typical example is the flexible multilayer thermal barrier for launch vehicle base region which experiences both radiative heating from the plume and hot nozzle divergent as well as convective heating due to reverse flow. To design and evaluate the effectiveness of the thermal barrier, simultaneous simulation of both radiative and convective heating is essential. This was made possible by the utilization of controlled radiant heaters and a Convective Heating System (CHS), both acting simultaneously in a pre-designated sequence. Such a simulation is very challenging since, the simultaneous simulation of radiative heating and convective heating mutually interferes with their respective independent control systems. Besides, the influence of the boundary conditions in the heat transfer process is different for radiative and convective heating. Hence, a novel technique was adopted to isolate the respective control systems. Detailed tests were undertaken to map the flow field at various distances from the exit to determine the position of the test article. After extensive mapping, the facility was utilized for simulations of both radiative and convective heating simultaneously on a thermal protection element in the launch vehicle base region, which experiences simultaneous simulation of convective and radiative heating. The studies were able to bring out the effect of hot gas permeability and thermal response and ascertain that the back wall temperatures are within allowable temperature constraint. This mode of simulation is a new technique where both simultaneous simulation of convection and radiation was undertaken to simulate the actual environments of flight on a specific system

Moisture Adsorption-Desorption Behaviour in Nanocomposite Copolymer Films.

Dehumidifying air via refrigerant cooling method consumes a tremendous amount of energy. Independent humidity control systems using desiccants have been introduced to improve energy efficiency. This research aimed to find an alternative to the commonly used solid desiccant, silica gel, which has weak physical adsorption properties. It also aimed to overcome the limitation of liquid desiccants that may affect indoor air quality and cause corrosion. This study reports on the synthesis of poly(vinyl alcohol-co-acrylic acid), P(VA-AA), through solution polymerisation by hydrolysing poly(vinyl acetate-co-acrylic acid), P(VAc-AA). This viable copolymer was then incorporated with graphene oxide (GO) at different concentrations (0 wt.%, 0.5 wt.%, 2 wt.% and 5 wt.%) to enhance the adsorption-desorption process. The samples were tested for their ability to adsorb moisture at different levels of relative humidity (RH) and their capability to maintain optimum sorption capacity over 10 repeated cycles. The nanocomposite film with 2% GO, P(VA-AA)/GO2, exhibited the highest moisture sorption capacity of 0.2449 g/g for 60-90% RH at 298.15 K, compared to its pristine copolymer, which could only adsorb 0.0150 g/g moisture. The nanocomposite desiccant demonstrated stable cycling stability and superior desorption in the temperature range of 318.15-338.15 K, with up to 88% moisture desorption.

A novel calibration method for angular misalignment in independently controlled fast tool servo-based diamond turning

With significant technological progress in optics fields, such as VR and 3D sensing technologies, the demand for optical components with complex shapes (e.g., freeform surfaces) has expanded significantly in recent years. Ultra-precision diamond turning is one of the common manufacturing methods used for freeform optics. There are two tool-motion mechanisms for freeform diamond turning: slow tool servo (STS), which moves the entire tool rest, and fast tool servo (FTS), which only drives the diamond tool. In particular, high-frequency and long-stroke FTS units driven by a separate control system from the machine tool controller have recently been developed as a new trend in FTS-based diamond turning. However, this type of independent FTS control system causes a time delay between the machine tool instruction and the FTS tool motion. Even a millisecond-scale time delay can cause a considerable angular misalignment owing to the high rotation rate of the spindle, resulting in a micron-scale form error on the workpiece surface. In this paper, a novel method for precisely measuring the time delay from the machined workpiece surface and compensating for the misalignment based on the measured time delay was proposed. To measure the time delay, spherical dimples were machined on the workpiece surface by using STS and FTS. Subsequently, the angular misalignment and time delay were obtained by comparing the measured surface profiles at specific positions of the spherical dimples. Thus, the time delay can be measured with microsecond-scale accuracy. Based on the measured time delay, the shifted tool position along the spindle axis by the time delay was compensated to the ideal tool position by considering the cutting velocity. Consequently, the angular misalignment was completely eliminated, and submicron-level form accuracy was achieved. This calibration method of angular misalignment for an independent FTS unit is expected to significantly improve the accuracy of ultra-precision machining of freeform optics.

Extension coordinated control of distributed-driven electric vehicles based on evolutionary game theory

The control of vehicle chassis dynamics requires a fast and complex process, with constantly changing tire forces and vehicle states. When the control system is completely rational, there are coupling relations and functional redundancy among subsystems, which makes it difficult to achieve optimal overall performance. This paper proposes a hierarchical extension coordinated controller, which considers the bounded rationality of the control system to address traditional stability control interference on driving speed and driver operation. The supervisory layer uses the extension phase plane to divide the operating state of vehicles. The coordinated decision-making layer considers active front-wheel steering (AFS) and direct yaw moment control (DYC) as game bodies, establishing an evolutionary game model to determine coordination weights. Results from the Carsim/Simulink platform comparison with a completely rational independent control system indicate the bounded rationality coordinated controller achieves better stability control with less intervention on driving speed. Vehicle testing has confirmed the effectiveness of the coordination control strategy.

Efek Moderasi Moralitas Individu terhadap Hubungan Pengendalian Internal dan Kecendrungan Kecurangan

Purpose: The aim of this research is to examine the moderating effect of individual morality on the relationship between internal control system and the tendency of village financial management fraudulency Methodology/approach: The sampling method was purposive sampling with a total sample of 51 respondents from 20 villages in Ambon City. The data collection technique used was a survey technique using questionnaires. Data analysis used moderated regression analysis Results/findings: The results of the study explained that the internal control system has a negative effect on the tendency of fraudulence and individual morality, which acts as a moderating variable that strengthens the relationship between the internal control system and the tendency of village financial management fraudulency. Limitations: The results of this study indicate that the independent variables internal control system and individual morality as moderating variables only affect the tendency of fraud in village financial management by 30.9%, meaning more than 69.1% are influenced by other factors outside the model. Other factors can be in the form of competence of village officials, as well as compliance with regulations and other behavioral factors that can contribute to the tendency of village financial management fraudulency. Contribution: For the government traditional villages in Ambon City to make the role of state saniri more effective which carries out the supervisory function as the implementation of the internal control function to prevent the occurrence of village financial management that is not in accordance with the rules and can lead to fraud. Novelty: This research was conducted in a village in Ambon City which has the status of a traditional village whose village government system upholds local customs and wisdom so that it is different from other villages based on administrative area.

Integrated vehicle control using adaptive control allocation

SummaryThe focus of this paper is an integrated, fault‐tolerant vehicle control algorithm for the overall stability of ground vehicles. The proposed scheme comprises a high‐level controller that creates a virtual control input and a low‐level adaptive control allocator that distributes the virtual control effort among redundant actuators. The proposed control framework distinguishes itself from earlier results in the literature by its ability to blend active suspension, steering and traction control channels, in the presence of uncertainties and time‐varying dynamics, without the need for fault identification. The control structure is validated in the simulation environment using a fourteen‐degree‐of‐freedom non‐linear vehicle model. The integrated controller is compared to the case of a conventional control approach where each control problem is solved separately. Our results show that, compared to the conventional approach, the proposed method ensures that the vehicle follows driver inputs with up to % higher longitudinal maneuver velocity, despite the presence of actuator failures and slippery road conditions. Furthermore, to demonstrate the benefit of integrating active suspension control to the overall control scheme, we replaced the suspension control of the proposed approach with an independent suspension control system for comparison purposes. We then showed that the integrated case provided % lower roll angle deviation, and % lower pitch angle deviation, in the presence of actuator effectiveness loss and adverse road conditions.

Development of a dynamic motion platform with two independent drive systems for radiotherapy

There are some motion platforms for radiotherapy quality assurance. However, no platform with two drive systems that can move along three axes is available. The purpose of this study is to develop a dynamic motion platform with two drive systems capable of three-axis motion and to evaluate its motion performance. The developed moving platform had two drive systems that use the same equipment. Each axis of the platform used can support a maximum load of 10kg. The motors for moving the platform in each direction are capable of a drive stroke up to 40mm. The drive speed is 30mm/s at maximum load fluctuation. To evaluate the static positional accuracy of this system with an arbitrary input movement, the XYZ position of each axis was measured using a coordinate measuring machine operating from 0 to 40mm at 10mm intervals. In addition, the accuracy of dynamic motion was verified with Sine waveform inputs of different patterns to the three axes for approximately 60 s, and they were compared with the resulting detected signals by SyncTrax. The two drive systems were successfully operated on three axes by using independent control systems. For static position, the accuracies were within 0.2mm, 0.05mm, and 0.14mm for lateral, longitudinal, and vertical directions, respectively. For dynamic motion, the mean absolute errors in the X, Y, and Z axes between the platform inputs and SyncTrax detected signals were 0.14±0.10mm, 0.16±0.12mm, and 0.16±0.11mm, respectively. A new dynamic platform for radiation therapy with two drive systems capable of three-axis motion was developed, and the positional accuracy of the drive axes was confirmed to be less than 0.2mm.

Variable Universe Fuzzy Controller for an Independent Metering System of Construction Machinery

As a new type of hydraulic system, the independent valve control system (IMCS) has higher flexibility compared with the traditional four-side slide valve control system. The independent metering control system (IMCS) is divided into four quadrant modes, based on the speed and load of the actuator. The traditional control methods always use a discrete control strategy to realize the switching between different modes based on mode recognition. However, the spool signals frequently switch, and the actuator operating pressure and speed are not stable when the IMCS is switched between different modes. To solve the above problems, this paper proposes a continuous control strategy for the IMCS. Based on the fuzzy control principle, the variable universe fuzzy controller (VUFC) was designed. The controller contains 49 fuzzy rules, and the output of the controller at any time is calculated by the weighted sum of several fuzzy rules. The VUFC divides the system into 49 rules, which are activated by multiple modes at any time to achieve a smooth transition between different modes. The VUFC was verified in a 37 ton excavator model and compared with the traditional independent metering meter-out (IM_MO) control strategy. The results showed that the VUFC significantly improved the frequent switching of the spool signals, and the running speed and pressure stability of the hydraulic cylinder were significantly improved. At the same time, the response speed of the hydraulic cylinder became faster at the start of the system. The VUFC can realize the continuous control of the IMCS and improve the operating performance of excavators.

Integrated Small Animal PET/CT/RT with Onboard PET/CT Image Guidance for Preclinical Radiation Oncology Research.

We have integrated a compact and lightweight PET with an existing CT image-guided small animal irradiator to enable practical onboard PET/CT image-guided preclinical radiation therapy (RT) research. The PET with a stationary and full-ring detectors has ~1.1 mm uniform spatial resolution over its imaging field-of-view of 8.0 cm diameter and 3.5 cm axial length and was mechanically installed inside the irradiator in a tandem configuration with CT and radiation unit. A common animal bed was used for acquiring sequential dual functional and anatomical images with independent PET and CT control and acquisition systems. The reconstructed dual images were co-registered based on standard multi-modality image calibration and registration processes. Phantom studies were conducted to evaluate the integrated system and dual imaging performance. The measured mean PET/CT image registration error was ~0.3 mm. With one-bed and three-bed acquisitions, initial tumor focused and whole-body [18F]FDG animal images were acquired to test the capability of onboard PET/CT image guidance for preclinical RT research. Overall, the results have shown that integrated PET/CT/RT can provide advantageous and practical onboard PET/CT image to significantly enhance the accuracy of tumor delineation and radiation targeting that should enhance the existing and enable new and potentially breakthrough preclinical RT research and applications.

Highly sensitive and quantitative fluorescent strip immunosensor based on an independent control system for rapid detection of tetrodotoxin in shellfish

Tetrodotoxin (TTX) in shellfish poses a serious public health threat, and there is thus an urgent need to develop an accurate approach for detecting TTX. In this study, a new method of rapid detection using an immune strip sensor achieved on-site detection of TTX in shellfish. Time-resolved fluorescent microspheres were used as fluorescent labels that were conjugated with anti-TTX antibody as a detection probe. Meanwhile, a streptavidin-biotin system was introduced as an independent control system to make the fluorescence intensity of the control line more stable. The developed immune strip sensor could achieve rapid detection of TTX within 20 min; the detection limit was as low as 0.05 ng/mL with the linear range of 0.5–40 ng/mL, and the acceptable recovery was 97–102%. The reliability of this method for real sample detection was verified by the comparison to the results of ultra-performance liquid chromatography/tandem mass spectrometry. The proposed method provides an effective approach for instant screening and detection of TTX in shellfish samples.

FAKTOR INTERNAL ORGANISASI DAN PENCEGAHAN FRAUD PADA PENGELOLAAN WISATA MANGROVE DI MADURA

Abstract—This study aims to identify many factors that can influence fraud prevention in management of mangrove ecotourism in Madura. The population in this study was all management of mangrove ecotourism in Madura. This research uses quantitative methods with several independent variables, namely integrity, organizational culture, accountability and internal control systems, while the dependent variable is fraud prevention. This study uses primary data by distributing questionnaires to pokdarwis’s members and managed to obtain 161 respondents. Multiple linear regression analysis is used for data analysis The result indicates that organizational culture and internal control systems have a positive effect on fraud prevention. It is caused by the implementation of transparency through using information boards in tourism management has not been maximized. Different results are obtained in which integrity and accountability have no effect on fraud prevention. Pokdarwis’s members are always monitoring and formation of an organizational culture that is aware of fraud prevention actions are the reasons for its influence.
 
 Keywords: Integrity; Organizational Culture; Accountability; Internal Control System; Fraud Prevention.

Cable vibration mitigation by using an H‐bridge‐based electromagnetic inerter damper with energy harvesting function

The mitigation of bridge cable vibration has long been a research hotspot with substantial developments contributed to the field. In addition to vibration control, a recent development trend incorporates auxiliary sensors, local computing modules, and data transmission devices to establish a comprehensive, integrated cable control and health monitoring system, which requires external energy input. However, an external power supply for these devices is not considered an attractive option, considering that the kinetic energy embodied in cable vibrations can be potentially harvested to cover such power demand, leading to the establishment of an independent self-powered control and health monitoring system. In this regard, we proposed an unprecedented solution for cable vibration mitigation by developing a novel H-bridge-based electromagnetic inerter damper (HB-EMID) in this work, in which HB-EMID can emulate the control behavior of an inerter damper and possess an energy-harvesting function. Meanwhile, the newly proposed HB-EMID is granted with great flexibility that can alter its equivalent mechanical properties by merely adjusting the corresponding coding. Following the introduction of the system topology and working mechanism, this study applies an HB-EMID to a cable structure and systematically investigates the balanced control and energy-harvesting performances, as well as its feasibility to full-scale application. Both satisfactory control performance and sufficient harvested power are confirmed through numerical validation.