Multichannel Control System Research Articles

Multi-channel decentralized decoupling FxLMS algorithm and active vibration control experiment

When vibrations generated by marine machinery propagate through a ship’s hull into the ocean, they produce low-frequency radiated noise with distinct “acoustic fingerprint” characteristics. This noise, characterized by stable and concentrated energy, long transmission distances, and difficulty in elimination, becomes the primary target for enemy sonar detection. Active vibration isolation serves as a critical method for reducing low-frequency vibrations in ships and enhancing their acoustic stealth performance. However, control challenges persist, including multi-frequency excitation, frequency fluctuation, multi-channel coupling, and slow convergence speed. To address these issues, this paper introduced an innovative multi-channel decentralized decoupling filtered-x least mean square (DMFxLMS) algorithm. Firstly, a recursive least squares identification algorithm with a forgetting factor was proposed, taking into account the characteristics of single-input, multi-output and multi-input, and multi-output control systems, effectively enhancing the algorithm’s convergence speed and control accuracy. Secondly, based on the decentralized decoupling control concept, the multi-channel control system was simplified into parallel single-channel control loops. The control weight coefficient updates were only related to adjacent error signals, significantly reducing the algorithm’s computational complexity. Thirdly, an anti-impact link was designed to improve the algorithm’s robustness, considering the interference caused by other mechanical equipment during the control process. The influence of abnormal error signals in the control weight coefficient correction term was suppressed, and a percentage function was introduced to limit the output signal. Finally, the feasibility and effectiveness of the DMFxLMS algorithm were verified through simulations and experiments. The results demonstrated that the DMFxLMS algorithm achieved significant control effects for both constant frequency line spectrum excitation and frequency fluctuating line spectrum excitation, fulfilling the objective of reducing base vibration. The DMFxLMS algorithm exhibited fast convergence and excellent robustness, making it suitable for practical engineering applications.

MCSG: A Morphology Configurable Soft Gripper With Self-Adaption Modular Composite Finger

Current soft grippers lack active variable stiffness composite fingers and flexible modular configuration, which limit their robust grasp abilities. We proposed a morphology configurable soft gripper (MCSG) assembled with self-adaption modular composite fingers (SAMCFs), whose grasping force can be up to 193N. The SAMCF with three actuator modules embedded arranged sponge and paperboard and one sensor module made with pre-inflated air chamber is developed to perform soft grasp with high load capacity and self-sensing ability. Through assembling corresponding SAMCFs to main frame, MCSGs with dual fingers (MCSG-DF), with three fingers (MSCG-TF), with four fingers (MSCG-FF) and with six fingers (MSCG-SF) are manufactured to adapt for grasping objects with different shapes, sizes, and weights. A pneumatic control system with hybrid valve combination is designed to output air pressure from negative to positive to perform contraction and elongation motion simultaneously, and output positive pressure to provide preset pressure for sensor modules. Finally, a multi-channel pneumatic control system is developed to control MCSGs to grasp a variety of objects, such as cherry tomato (10g), egg (170g), banana (155g), stool (3570g), etc. Furthermore, MCSGs can complete complicated tasks in daily life, such as water decanting, bottle cap unscrewing, mobile phone charging and water pumping.

Frequency domain adaptation of multichannel active road-noise sound control system with virtual sensing

The convergence speed of multichannel adaptive active noise control algorithms can be improved by pre-whitening the reference signals and reducing their cross-correlations. When considering nonstationary processes, like road noise, it proves advantageous to use a short time-based cross-correlation estimation of the reference signal, which can be obtained as part of the bin-normalised frequency domain least-means-squares algorithm. However, the regularisation of such an algorithm is crucial to its success and can further improve the convergence rate. In addition, virtual sensors can be employed by using the additional filter method, which provides targets for the measured error signals to follow, generated from the reference signals. Still, the performance of this virtual sensing is known to be degraded if the properties of the reference signals change, so special consideration should be taken when the reference signals are nonstationary.

DEVELOPMENT OF THE POWER SUPPLY AND CONTROL SYSTEM FOR THE HEMODIALYSIS MACHINE

The article describes new approaches to creating an autonomous compact system with automatic control for hemodialysis. It is proposed to organize a closed circuit for cleaning the dialysis solution using an electrolytic regenerator as a function of the concentration of urea in it. The functional diagram of the created system is presented and described. To power the regenerator, ensure thermal stabilization of the solution, and power auxiliary electronic and electrical equipment, a multi-channel power supply and control system for the hemodialysis machine based on high-frequency magnetic amplifiers has been developed and researched. The advantages of power switches based on high-frequency magnetic amplifiers in comparison with transistor switches, including in the construction of controlled power sources, are given. The principle of operation of the voltage regulator on high-frequency magnetic amplifiers is described. Theoretical and experimental oscillograms are given. Photographs of the experimental unit as well as an industrial sample of the multi-channel power supply and control system of the hemodialysis machine are provided. Their main technical characteristics are given. Conclusions to the conducted work are formulated. Carrying out the regeneration of the dialysis solution significantly reduces its costs – 2 liters of solution, which is suitable for use for 6 months, is enough for the operation of the device. Existing hemodialysis machines are a stationary open system using a single-use dialysis solution at a rate of up to 35 l/h, which ties the machine to stationary clinical conditions. Introducing feedback on the concentration of urea in the dialysis solution allows you to automate the blood purification procedure, as well as automatically complete hemodialysis at the necessary time, and also eliminates the dependence of the device on the conditions of the hospital.

A hybrid feedforward/feedback multi-channel active control system with optimization for cancelling road noise inside a vehicle cabin

A hybrid feedforward/feedback multi-channel system was developed for active road noise control (ARNC) inside a vehicle cabin. First, a centralized feedforward subsystem was present with a multi-channel normalized weighted error FxLMS algorithm, including a simplified reference signal normalization method, a reconstructed filter bank for filtering the reference signals, and a newly defined cost function of A-weighting error signals. Second, a distributed feedback subsystem was presented with multiple feedback single-channel simplified normalized FxLMS algorithms. By combining the two subsystems, a hybrid ARNC system was developed. Furthermore, data related to the ARNC system were collected from the test vehicle. Next, a nondominated sorting genetic algorithm-II was introduced to optimize the system parameter. Multi-objective optimization models of the feedforward and hybrid ARNC systems were established respectively, and the optimal Pareto solution sets for their parameters were obtained. Real-time experiments show that, when the test vehicle driving at 60 km/h on the small brick pavement, the developed hybrid ARNC system can achieve an overall noise reduction of 5.87 dBA in the time domain, and a peak noise reduction of 7.43 dBA in the frequency-domain. Compared with the feedforward ARNC system, road noise reduction is much improved. It still has a good noise reduction effect at other speeds and on different roads.

Design of Guided Bending Bellows Actuators for Soft Hand Function Rehabilitation Gloves

This study developed a soft pneumatic glove actuated by elliptical cross-sectional guided bending bellows to augment finger-knuckle rehabilitation for patients with hand dysfunction. The guided bending bellows actuators (GBBAs) are made of thermoplastic elastomer (TPE) materials, demonstrating the necessary air tightness as a pneumatic actuator. The GBBAs could produce different moments of inertia when increasing internal air pressure drives the GBBAs bending along distinct symmetry planes and exhibits anisotropic kinematic bending performance. Actuated by GBBAs, wearable soft rehabilitation gloves can be used for daily rehabilitation training of hand dysfunction to enhance the range of motion of the finger joint. To control each finger of the gloves independently to achieve the function of manipulating gestures, a multi-channel pneumatic control system is designed, and each air circuit is equipped with an air-pressure sensor to make adjustments based on feedback. Compared with general soft robotic exoskeleton gloves currently used for hand dysfunction, the GBBAs actuated soft gloves have the advantage of enhancing the rehabilitation strength, finger movement range, and multi-action coordination applied with guided bending bellows actuators.

Research and application of ultra-high pressure control system in strength tests

Based on the requirement of physical experiments, a ultra-high pressure control system which consisted of servo valves, a booster cylinder, and a multi-channel synchro-loading control system, was designed. A multi loop control strategy was adopted in this system, and hydraulic oil was loaded on the low-pressure side of the booster cylinder. In this way, the high precision control of low pressure increasing with high flow was attained, either was ultra-high pressure increasing, maintaining and reducing with low flow. The system was applied in a landing gear strength test successfully, the pressure control accuracy was smaller than 0.5 %, and the test task was completed satisfactorily.

Расчет регулятора для многоканального объекта с нестационарными параметрами, содержащего звенья запаздывания

Nonstationary linear systems or linear systems with variable parameters are systems that are described by linear differential equations with variable coefficients. Consideration of the controller synthesis problems for such systems may be dictated by the need to satisfy a certain margin of the automatic control system stability to minor disturbances both from sensors reading the state of the system and from changes in the parameters of the controlled object itself over time. In addition, a real controlled object, in comparison with its mathematical model, quite often contains some uncertainties that should not significantly affect the quality of control.This work considers an example of synthesizing a multichannel controller that would provide a good control quality (stability margin) if the controlled object contains some uncertainties or if its mathematical model with accuracy up to certain parameters is unknown. In addition, the control task is complicated by a link of delay in the structure of the object (that is, there is a certain period of time when there is no reaction from the regulated object to the control action).A modified algorithm of polynomial matrix decomposition of the matrix transfer function of the system, taking into account the conservation of the delay link poles, is chosen as a method of controller synthesis. To demonstrate the algorithm operation, a linear model of the unstable controlled object with a multi-channel structure consisting of two input and two output channels is taken. The description of the object is used in the form of the matrix transfer function, which shows the interaction in the multi-channel control system and the relationship between channels. The object model contains cross-links representing direct input-output connections. The delay links are present in all channels and are approximated using the Pade series with a limited number of terms. The non-stationary parameters of the object were obtained due to the multiplicative interference modeled in the Simulink Matlab package.It is necessary to achieve certain quality indicators of the output vector process when controlling two input influences. To ensure a stable transition process from the system, the poles preservation of the delay link will be necessary. Then the controller calculated for the system with the delay link in the form of the Pade series is applied to the system with an "ideal" delay.

Автоматизированная система управления электроприводами с интеграцией программируемых реле и активных фильтров

This paper discusses relevant challenges in upgrade of control systems and reviews possible applications of new programmable relays OVEN PR10 for non-stop Ethernet data transmission. It also discusses integration of active power filters in feeding circuits of electric drives with upgraded automatic control systems. The study analyses the applications of active filters and suggests a testing system that consists of electric compressor drives and automated multi-channel control system with integrated active filters. The tests performed under this study have shown that automatic systems work more efficiently if they are fed by high-quality loading current from their electric drives and are governed by OVEN PLC110 programmable logic controllers. This paper also describes a case study: laboratory experiment on integrating active power filter for interharmonic current components with multi-channel drive control system based on cutting-edge programmable relay OVEN PR103. The results of this study could be useful for the upgrade of Russian fishing fleet, as well as for design and development of innovative ships.

STRUCTURAL ANALYSIS OF ON-BOARD MULTIMODE AUTO TRACKING SYSTEM

Two variants of two-channel structures of tracking systems has been introduced into consideration, which are sequentially used in two modes of operation of the on-board automatic tracking system. Taking into account the fact of quantization according to the level of signals for measuring the angles of mismatch of each of the channels, it is justified to use not one, but two different structures in the second auto-tracking mode. Using mathematical modeling, the expediency of increasing the number of two-channel structures from two to three, used in a single auto-tracking process according to the criterion of the provided dynamic accuracy, have been demonstrated. This paper presents a two-channel structures investigation for tracking systems operating in tracking mode of maneuverable targets, taking into account various systems of carrier operations. Considered multichannel complex control system (CCS) structure that include precise channel (PC) and coarse channel (CC). CC use the carrier and the flight control system (FCS) to make rude tracking. The PC function implemented by an optoelectronic device (OED) has placed in a traditional angular mechanical suspension, which act with high accuracy. Described three CCS operation modes classified by target mark fall inside or outside direction finder (DF) CC or PC field of view. At the capture mode can be used only information from the CC DF. At the complex control mode becomes possible to use information from both CC DF and PC DF. At the precision mode, it is advisable to use information only from the PC DF. Developed CCS functioning math model to check main points of this work. Math model makes possible to carry out simulation tests for each mode in a separate operation, as well as when they are integrated into a single complex automatic target tracking mode. Has been described efficiency factor as the total time of satisfactory accuracy relative to entire experiment time. On math model modes efficiency has compared to each other. As result precision mode have higher efficiency and capture mode lowest. As conclusion recommended use a precision mode to achieve higher accuracy at auto tracking tasks.

Flow-Field-Assisted Dielectrophoretic Microchips for High-Efficiency Sheathless Particle/Cell Separation with Dual Mode.

Prefocusing of cell mixtures through sheath flow is a common technique used for continuous and high-efficiency dielectrophoretic (DEP) cell separation. However, it usually limits the separation flow velocity and requires a complex multichannel fluid control system that hinders the integration of a DEP separator with other microfluidic functionalities for comprehensive biomedical applications. Here, we propose and develop a high-efficiency, sheathless particle/cell separation method without prefocusing based on flow-field-assisted DEP by combining the effects of AC electric field (E-field) and flow field (F-field). A hollow lemon-shaped electrode array is designed to generate a long-range E-field gradient in the microchannel, which can effectively induce lateral displacements of particles/cells in a continuous flow. A series of arc-shaped protrusion structures is designed along the microchannel to form a F-field, which can effectively guide the particles/cells toward the targeted E-field region without prefocusing. By tuning the E-field, two distinct modes can be realized and switched in one single device, including the sheathless separation (ShLS) and the adjustable particle mixing ratio (AMR) modes. In the ShLS mode, we have achieved the continuous separation of breast cancer cells from erythrocytes with a recovery rate of 95.5% and the separation of polystyrene particles from yeast cells with a purity of 97.1% at flow velocities over 2.59 mm/s in a 2 cm channel under optimized conditions. The AMR mode provides a strategy for controlling the mixing ratio of different particles/cells as a well-defined pretreatment method for biomedical research studies. The proposed microchip is easy to use and displays high versatility for biological and medical applications.

Mathematical model of free-flying space manipulation robot when approaching a non-cooperative spacecraft

The paper investigates the service satellite control system when approaching a non-cooperative spacecraft in the state of uncontrollable motion. The service satellite control system is considered as a two-level multichannel control system, and multicriteria optimization methods with cross-links are developed. The mathematical model of the control system for a free-flying space manipulation robot at the guidance and stabilization phase is proposed. The efficiency criteria are presented.

Algorithm for Multi-Channel Robotic Device Control Based on Minimizing Bayesian Risk

Currently, mobile robotic devices are widely used in various fields of human activity, which imposes high requirements on the reliability of their operation. Improving the reliability and quality of control of mobile robotic devices is possible through the use of multi-channel control systems. Signals coming from different control channels are subject to various interference, which can lead to wrong decisions. In this regard, the problem of minimizing the risk of making an incorrect control decision is urgent. This paper gives a theoretical justification for the algorithm for choosing a control command for a multi-channel control system of a mobile robotic device. The algorithm is based on minimizing the Bayesian risk of choosing an erroneous command. To implement the algorithm, it is necessary to have statistical information about the quality of functioning of each control channel.

Synthesis of a Control Algorithm for Nonlinear Plant Using Correction of Controlled Plant Dynamics and Compensation of Perturbations

This paper introduces a new approach to control of nonlinear non-stationary multichannel plant with lumped parameters and additive perturbations. Controlled plant is represented as a set of equations in matrix-vector form, with number of output variables equal to the number of controlled variables. The problem is stated as follows: to control plant output provided that output variables and state variables are observable. Plant equations are converted into a state dependent coefficient (SDC) form, then method of correction of plant dynamics and compensation of perturbations is used. A variant of conversion to the SDC form based on E. A. Barabashin’s method is suggested. Reverse models of the plant are defined with respect to reference and deviation channels. Algebraic equations are presented, which, when solved, yield reverse models. Definitions of etalon filters are introduced, allowing a physical implementation of a controller when used in conjunction with reverse models. Conditions to which matrices of etalon filters must conform are considered. It was found by examples that part of coefficients of etalon filters can be chosen arbitrarily. Using the method of correction of controlled plant dynamics and perturbations, utilizing reverse models and etalon filters, a physically implementable controller algorithm was constructed. Then it was transformed to physically implementable form using equivalent transformations. Components of the final algorithm are obtained by the means of algebraic transformations of functional matrices of the plant and etalon filter. Equations for closed control system are presented. It follows from these equations that system is asymptotically stable and that transient processes correspond with their respective etalon filters. Even though compensation method was used, a multichannel closed-loop control system was obtained. An advantage of suggested method is that it allows a simple procedure for the control algorithm synthesis using evident physical initial data. The efficacy of obtained algorithms was verified using several examples. Computer simulation showed that control systems are robust and comply with specified requirements. Directions for further research were suggested.

Induction heating system aluminum alloy cylindrical billets

This publication discusses the task of developing an induction heating system for billets made of aluminum alloy with a given limit on the permissible temperature deviation. The purpose of the work is to determine the parameters of the inductor sections and the settings of the control system to achieve a given distribution of the billet before being fed under the press. The complexity of the problem is associated with the presence of several heater sections that differ in length from the workpieces, which leads to an additional factor leading to an increase in the unevenness in the distribution of temperature in the load. The model of the electromagnetic process is built taking into account the change in resistivity in the workpieces. When searching for a more efficient calculation algorithm, a joint solution to the thermal and electromagnetic problems is considered, which allows to simplify the procedure for exchanging data between applications. This approach is very convenient for solving problems that are not connected with harsh conditions with the achievement of the final state. When modeling thermal processes, the formulation of the problem takes into account all the features associated with radiant heat transfer between extended surfaces having different temperatures, temperature dependences of the workpiece parameters, a varying heat release region due to displacement. As options for a heating system, software control and a multichannel system with control correction for temperature control at one point are considered. When simulating a multi-channel heating control system, built-in software functions were used that made it possible to form control actions for each channel and recommend the location of temperature sensors providing high-quality control of heating.

Разработка многоканальной системы управления многофазным синхронным электроприводом с улучшенными виброшумовыми характеристиками

Constantly increasing requirements for the performance of electromechanical systems include the task of improving the vibration and noise characteristics of the electric drive. Currently, this problem is solved mainly by using traditional three-phase systems. The transition to a multiphase version of the electric drive construction opens up new opportunities for its solution. The aim of the study is to improve the vibration and noise characteristics of the electric drive through the development of a multiphase control system that provides targeted formation of the field configuration in the gap of a multiphase electric machine. To conduct the research, the model of a multiphase synchronous motor proposed by the authors was used. The model considers the spatial non-sinusoidality of the field distribution in the gap and enables to represent the engine as a set of parallel substructures, the number of which depends on the number of phases. The technique to design a synchronous motor with an arbitrary number of winding phases based on the field model of the machine has been proposed. The correctness of the results obtained is ensured by the real geometry of the magnetic circuit and steel saturation. The multi-channel control system of the electric drive, characterized by the targeted formation of field configuration in the gap of a multiphase electric machine has been proposed. The calculation model of the electric drive has been developed. The model combines the field model of the engine and the control system. The engine model is implemented in the ElСut software package, the control system model is implemented in the MatLab (Simulink) complex. Compared to the traditional three-phase design of the electric drive with a sinusoidal supply voltage, the options for forming a field in the gap of a synchronous motor considered in the article provide a reduction in ponderomotive force by 8–14 %. The engineering methodology for designing an m-phase synchronous permanent magnet motor with permanent magnets and the structure of the multi-channel control system can be applied when developing electric drives with improved vibration and noise characteristics.

An active noise control casing using the multi-channel feedforward control system and the relative path based virtual sensing method

Active noise control (ANC) is a noise reduction technique based on acoustic wave superposition. The sound pressure level is reduced in a zone of quiet (ZoQ) by an anti-noise wave transmitted from the control source. The anti-noise wave has the same amplitude and opposed phase of the noise wave. An error microphone is conventionally placed at the target ZoQ to monitor the sound pressure level, forming a closed-loop control in an ANC system. However, due to application constraints or physical limitations, the error microphone sometimes cannot be placed at the target ZoQ. Virtual sensing (VS) methods are developed for such situations. There are two most commonly used VS methods. They are the auxiliary filter based VS (AF-VS) method and the remote microphone based VS (RM-VS) method. The AF-VS method preserves the information regarding the optimal control filter that can achieve the maximum noise reduction at the target ZoQ. The RM-VS method estimates the disturbance signal at the target ZoQ based on remote measurements. In this paper, we propose a new VS method, the relative path based VS (RP-VS) method, which estimates both the disturbance signal and the anti-noise signal at the target ZoQ. A theoretical analysis is provided to demonstrate that under different assumptions of varying acoustic paths, the RP-VS method can behave in the same way as the AF-VS method or the RM-VS method. Simulation results validate this theoretical analysis and demonstrate that improved noise reduction can be achieved by the RP-VS method when the noise frequency varies. Lastly, an ANC casing is built up with the RP-VS method to reduce a varying broadband fan noise. The RP-VS method is validated to be as effective as the AF-VS method and the RM-VS method with the implementation of the ANC casing.

Online multi-channel secondary path modeling in active noise control without auxiliary noise.

Online secondary path modeling is always appealing in active noise control due to the benefit of tracking the variations in the secondary path while exerting noise control simultaneously. However, the auxiliary noise usually utilized in online modeling contributes to the residual noise and deteriorates the noise control performance. This problem is more severe in multi-channel active control systems. Recently, it has been revealed that the secondary path can be identified using the output of the control source directly without injecting any auxiliary noise. In this letter, this strategy is extended to the multi-channel case. The reliability of the secondary path modeling is theoretically proven, and the effectiveness of the proposed multi-channel simultaneous modeling and control system is validated through simulations using measured impulse responses.

Online secondary path modeling method with auxiliary noise power scheduling strategy for multi-channel adaptive active noise control system

Accurate model of secondary paths is very crucial for the multi-channel filtered-X least mean square algorithm applied in adaptive active noise control system. The auxiliary random noise technique is popular for online secondary path modeling during adaptive active noise control operation. This paper proposes a simplified variable step-size strategy and an effective auxiliary noise power scheduling strategy for the multi-channel filtered-X least mean square algorithm. Through a defined indirect error signal, the proposed method can guarantee every online secondary path modeling filter has its own exclusive variable step-size strategy to update their coefficients, and every injected noise has its own exclusive scheduling strategy considering all of the corresponding online secondary path modeling filters. The proposed method can improve the adaptive performance and simplifies the complexity of multi-channel adaptive active noise control system. Computer simulations show that the proposed method gives much better noise reduction and secondary path modeling accuracy at a somewhat faster convergence rate comparing with the competing methods.

Case Study on Human-Robot Interaction of the Remote-Controlled Service Robot for Elderly and Disabled Care

The tendency of continuous aging of the population and the increasing number of people with mobility difficulties leads to increased research in the field of Assistive Service Robotics. These robots can help with daily life tasks such as reminding to take medications, serving food and drinks, controlling home appliances and even monitoring health status. When talking about assisting people in their homes, it should be noted that they will, most of the time, have to communicate with the robot themselves and be able to manage it so that they can get the most out of the robot's services. This research is focused on different methods of remote control of a mobile robot equipped with robotic manipulator. The research investigates in detail methods based on control via gestures, voice commands, and web-based graphical user interface. The capabilities of these methods for Human-Robot Interaction (HRI) have been explored in terms of usability. In this paper, we introduce a new version of the robot Robco 19, new leap motion sensor control of the robot and a new multi-channel control system. The paper presents methodology for performing the HRI experiments from human perception and summarizes the results in applications of the investigated remote control methods in real life scenarios.