Composite Control Scheme Research Articles

Super-twisting resonant controller-based inverter nonlinearity compensation for permanent magnet synchronous motor drive system

In this paper, a novel super-twisting resonant controller with a fixed-time adaptive law (FTAL-STRC) is proposed to improve robustness and current smoothness of permanent magnet synchronous motor (PMSM). Firstly, the STRC controller is proposed, which incorporates the benefits of both the super-twisting controller (STC) and the quasi-resonant controller (QRC). Compared to the universal proportional integral resonant (PIR) control method, the proposed STRC can decrease the influence of inverter nonlinearity, and improve the robustness to parameters change, simultaneously. Secondly, an adaptive law based on fixed-time convergence theory (FTAL) is proposed to further compensate for the unknown disturbance, and realize fast tracking. Then, the composite control strategy is developed. Meanwhile, the stability of the proposed FTAL-STRC is proved rigorously. Finally, simulations and experiments are conducted to validate the effectiveness of the proposed method.

Sensorless model predictive control based on I‐f integrated sliding mode observer for surface permanent magnet synchronous motor

SummaryDue to the limited fast dynamic response of the dual proportional‐integral (PI) control strategy in sensorless speed control, a novel composite control strategy is proposed for sensorless control of the full speed range of the surface‐mounted permanent magnet synchronous motor. This strategy combines dual closed‐loop model predictive control (MPC) with a sliding mode observer (SMO) and a constant current‐frequency ratio (I‐f). The I‐f control scheme is employed in the low‐speed range, while the SMO is utilized for motor speed and rotor position estimation in the medium and high‐speed ranges, enabling the dual‐loop MPC. Furthermore, a new smooth switching method is proposed for transitioning between the two control methods. In addition, the MPC outer loop parameters were thoroughly analyzed and optimized for better dynamic performance of sensorless control. The steady‐state performance of this control strategy is compared to PI control and improved the dynamic responsiveness of the system. Experiments have verified the feasibility of this strategy. Under the control of the MPC outer loop, the steady‐state speed fluctuation of the motor is within 10 r/min. Compared to PI control, the motor settling time was reduced by 17% and 60% during the start‐up phase and after a sudden speed change, respectively.

Deep reinforcement learning optimized double exponentially weighted moving average controller for chemical mechanical polishing processes

This study investigates a deep reinforcement learning (DRL)-assisted double exponentially weighted moving average (dEWMA) controller for run-to-run (RtR) control in the semiconductor manufacturing process. We focus on implementing parameter adaption of dEWMA controllers to achieve disturbance compensation and target tracking. Owing to the powerful adaptive decision-making capability of the DRL, the weight adjustment of dEWMA controller is formulated as a Markov decision process. Specifically, the DRL behaves as an assisted controller to derive appropriate weights that facilitate dEWMA to perform highly accurate disturbance estimation, whereas the standard dEWMA works as a baseline controller to provide suitable recipes for the manufacturing process. Consequently, a composite control strategy integrating DRL and dEWMA is developed. In addition, a twin-delayed deep deterministic policy gradient algorithm is employed to adjust the weights of dEWMA online. The effectiveness of the proposed scheme is validated in a chemical mechanical polishing process. Several disturbance rejection scenarios verify the benefits of the suggested approach.

Composite Disturbance Rejection Control Strategy for Multi-Quadrotor Transportation System

In this paper, a composite disturbance rejection control algorithm is developed for cooperatively carrying a cable-suspended payload in multi-quadrotor transportation system (MQTS). Firstly, based on the Newton Euler's method and orthogonal force decomposition, a precise MQTS model is established which takes a general rigid body payload into account. Then, a multi-loop control strategy is designed to deal with the coupled states and underactuation in MQTS, where the payload is expected to move along a desired trajectory. Furthermore, the disturbance observer (DOB) is introduced, and the disturbance estimation is incorporated in controller to actively compensate the effect of external disturbance in different control loop. Finally, the effectiveness of the proposed method is validated by simulation results.

Research on an Adaptive Compound Control Strategy of a Hybrid Compensation System

This paper investigates the parallel harmonic resonance problem for hybrid compensation systems, consisting of active power filters and thyristor-switched capacitors, and proposes an adaptive composite control strategy for solving the parallel harmonic resonance problem that may arise in practical applications of hybrid compensation systems. In practice, a hybrid compensation system can effectively solve harmonic and reactive power problems, but the equivalent reactance of the thyristor-switched capacitor and the supply line may form a parallel resonant circuit, which may generate parallel harmonic resonance when excited by a harmonic source at the non-linear load side, affecting the quality and stable operation of the system. The adaptive composite control strategy employs a second-order generalized integrator-frequency-locked loop (SOGI-FLL) to extract the harmonic voltage at the point of common coupling (PCC) and generate an adaptive damping current command using an adaptive algorithm, which adaptively adjusts the parameters of the resonance suppression controller through harmonic content limitation. Matlab/Simulink simulations show that the method effectively achieves harmonic resonance suppression of the power supply system under complex operating conditions, thus ensuring the stable operation and power quality of the power supply system. Therefore, the proposed control strategy is feasible and effective.

Finite Time Disturbance Observer Based on Air Conditioning System Control Scheme

A novel robust finite time disturbance observer (RFTDO) based on an independent output-finite time composite control (FTCC) scheme is proposed for an air conditioning-system temperature and humidity regulation. The variable air volume (VAV) of the system is represented by two first-order mathematical models for the temperature and humidity dynamics. In the temperature loop dynamics, a RFTDO temperature (RFTDO-T) and an FTCC temperature (FTCC-T) are designed to estimate and reject the lumped disturbances of the temperature subsystem. In the humidity loop, a robust output of the FTCC humidity (FTCC-H) and RFTDO humidity (RFTDO-H) are also designed to estimate and reject the lumped disturbances of the humidity subsystem. Based on Lyapunov theory, the stability proof of the two closed-loop controllers and observers is presented. Comparative simulations are carried out to confirm that the proposed controller outperforms conventional methods and offers greater accuracy of temperature, humidity, and carbon dioxide concentration, having superior regulation performance in terms of a rapid finite time convergence, an outstanding disturbance rejection property, and better energy consumption. In addition to presenting the comparative simulation results from the control applications on the VAV system, the quantitative values are provided to further confirm the superiority of the proposed controller. In particular, the proposed method exhibits the shortest settling time of, respectively, 15 and 40 min to reach the expected temperature and humidity, whereas other comparative controllers require a longer time to settle down.

Integral back-stepping active disturbance rejection control for piezoelectric stick-slip drive nanopositioning stage

Piezoelectric stick-slip driven nanopositioning stage (PSSNS) with nanometer resolution has been widely used in the field of micro-operation. However, it is difficult to achieve nanopositioning over large travel, and its positioning accuracy is affected by the hysteresis characteristics of the piezoelectric elements, external uncertain disturbances, and other nonlinear factors. To overcome the above-mentioned problems, a composite control strategy combining stepping mode and scanning mode is proposed in this paper, and an integral back-stepping linear active disturbance rejection control (IB-LADRC) strategy is proposed in the scanning mode control phase. First, the transfer function model of the system in the micromotion part was established, and then the unmodeled part of the system and the external disturbance were treated as the total disturbance and extended to a new system state variable. Second, a linear extended state observer was used as the core of the active disturbance rejection technique to estimate displacement, velocity, and total disturbance in real time. In addition, by introducing virtual control variables, a new control law was designed to replace the original linear control law and improve the positioning accuracy and robustness of the system. Furthermore, the effectiveness of the IB-LADRC algorithm was verified by simulation comparison experiments and experimentally validated on a PSSNS. Finally, experimental results show that the IB-LADRC is a practical solution for a controller capable of handling disturbances during the positioning of a PSSNS with a positioning accuracy of less than 20 nm, which essentially remains constant under load.

Composite-disturbance-observer-based backstepping control for three-phase inverters with multiple disturbances

This paper deals with the output voltage tracking control problem of three-phase inverters with multiple disturbances (including parametric perturbations of filter, abrupt disturbances caused by load switching, and harmonic disturbances brought by unbalanced loads and nonlinear loads). Some novel composite disturbance observers are designed to estimate the above multiple disturbances. Based on the disturbance estimates and backstepping control technique, an innovative feedforward-feedback composite tracking control scheme is proposed. The new control scheme has a good disturbance rejection ability and ensures good tracking performances. In the meantime, rigorous stability proof is presented. Simulation and experimental results are illustrated to verify the feasibility and effectiveness of the proposed control scheme.

Intelligent tunnelling robot system for deep-buried long tunnels

Existing tunnel boring machine (TBM) construction presents certain shortcomings. These include difficulty in comprehensive perception of information, poor timelines of information transmission and storage systems, significant effects of traditional data processing methods on the timeless of intelligent decision-making, and poor applicability of decision-making models and control strategies. In addition, the integration level of perception, decision-making, and control should be further improved. Therefore, a cross-platform deployable intelligent tunnelling robot system with closed-loop intelligent control functions of a “comprehensive perception, dual-driven decision-making, and composite intelligent control” is developed. Based on fieldbus, communication, database, cloud computing, and advanced exploration technologies, a multi-source information perception and integrated management platform based on a two-layer architecture is built to achieve the comprehensive perception of tunnelling information. In addition, an optimal decision-making method of the particle swarm optimisation (PSO) algorithm is simultaneously proposed for the minimum decision-making of tunnelling specific energy for scientific analyses and decision-making. A composite intelligent control strategy comprising multimodal and expert experienced learning control strategies is designed to achieve the control of conventional and unfavourable geological sections, respectively. Engineering cases verified the effectiveness and reliability of the intelligent tunnelling robot system. The research results not only provide new ideas and technical means for achieving the less-manned, unmanned, and intelligent tunnelling construction of deep-buried long tunnels but can also be promoted owing to its universality.

Robust composite repetitive control with disturbance observer for high-precision tracking of piezo-actuated nano-stages with measurement delays.

In this paper, a robust composite control strategy in the framework of unified infinite-dimensional H∞ optimal control is developed to support nano-scale periodic tracking with improved non-harmonic disturbance attenuation of piezo-actuated nano-stages with sensor-induced measurement delays. In particular, we analyze the electromechanical coupled dynamics and derive a multi-perturbation model, where an extended Youla-Kucera parameterization-based repetitive controller with a disturbance observer is constructed to optimize control performances on high-precision tracking and perturbation rejection. The controller parameters are solved by using a unified infinite-dimensional H∞ optimization method. Comprehensive experiments on a piezo-actuated stage are conducted, where comparative results with representative methods, such as the conventional repetitive control and proportional-integral-derivative control, demonstrate significant performance improvements in hysteresis compensation, trajectory tracking, and disturbance suppression of the proposed method.

Design and Analysis of the Composite Stability Control of the Reflective Optoelectronic Platform

To improve image object detection and tracking, researchers have been exploring methods to enhance the stability and precision of optoelectronic platforms’ line of sight (LOS). The innovation of stability mechanisms is the key driver of this breakthrough. This study presents a composite stability control system for reflective optoelectronic platforms using the integral composite stability principle. A platform kinematic model was established based on multi-body kinematic theory, and a composite stable control strategy was designed. The strategy includes coarse stability design and fine stability design based on residual error feed-forward correction. The performance of the control strategy was analyzed in terms of dynamics, current loop control effects, and loop structure. The proposed control strategy was simulated and experimentally verified for fixed-frequency angular velocity disturbance and translational disturbance. The stability accuracy index of the system was significantly improved after compensation, with improvement of more than 75 times for fixed-frequency angular velocity disturbance and more than 37% for translational disturbance. Comparative experimental results with traditional stable methods show that the proposed composite stable control strategy can significantly improve the system stability, with stability accuracy index improvement of one to two orders of magnitude in micro-radian units compared to traditional algorithms.

Disturbance observer‐based quasi‐proportional resonant composite control strategy for high‐frequency LCLC inverters

SummaryA quasi‐proportional resonant (QPR) composite control strategy based on disturbance observer (DOB) is proposed to improve the power quality and dynamic performance of the high‐frequency AC distribution system source side. The load DOB normalizes the controlled object while suppressing the load disturbance and improving the system's robustness and dynamic performance of the system. The QPR control strategy is proposed based on the internal mode principle, which improves the tracking capability of the system for the operating frequency band signal, reduces the system output steady‐state error, and suppresses the inverter output voltage harmonics. To adapt to the high bandwidth requirement of the controller for high‐frequency AC inverters, the proposed control strategy based on analogy devices implementation circuit is designed, and the corresponding controller parameters design method is given. Compared with the traditional control strategy, the proposed control strategy can reduce the inverter output voltage harmonics, effectively suppress the load disturbance, and improve the dynamic performance and steady‐state performance of the system. Finally, the experimental platform verifies the feasibility and effectiveness of the proposed control strategy and the designed circuit.

Disturbance observer-based fixed-time control for nonlinear systems with multiple disturbances

The fixed-time control is researched for the nonlinear system subject to multiple disturbances, which contain an external disturbance with unknown frequency and an unknown bounded disturbance. An adaptive nonlinear disturbance observer is devised to estimate the unknown frequency disturbance generated by an exogenous system. On this foundation, a composite fixed-time control scheme is proposed by combining the [Formula: see text] control and the fixed-time theory. It guarantees that the expected control performances of system can be achieved under the existence of multiple disturbances. Eventually, the validity of the control scheme is proved via simulation examples.

Command‐filter‐based fast finite‐time composite adaptive neural control for nonlinear systems with input dead‐zone

SummaryIn this paper, a command‐filter‐based fast finite‐time composite adaptive control scheme is proposed for nonlinear systems with input dead‐zone. The neural networks (NNs) are used to approximate the unknown functions of the controlled systems. The series‐parallel nonsmooth estimation models are used to predict the errors. In addition, the tracking error and prediction errors are anastomosed to update the weights of the NNs. To solve the problem of “explosion of complexity,” the command‐filter technology is adopted. Combining the Lyapunov stability theory and the adaptive backstepping algorithm, a composite adaptive backstepping control scheme is proposed. The proposed scheme dissolves the singularity problem which may emerge in the design process and the neural networks approximation performances can be realized as well. Meanwhile, the proposed scheme guarantees the tracking error converges into a small neighborhood of zero in fast finite‐time and the boundedness of all the closed‐loop signals. Finally, the simulation example is provided to verify the effectiveness of the proposed scheme.

Generalized Active Disturbance Rejection With Reduced-Order Vector Resonant Control for PMSM Current Disturbances Suppression

A control strategy that combines a novel reduced-order vector resonant controller and a generalized active disturbance rejection control (ROVR-GADRC) is proposed in this paper to suppress the current disturbances containing periodic harmonics of permanent magnet synchronous motor (PMSM). Firstly, the ROVR controller is designed, which integrates the advantages of both the complex coefficient filter and the vector resonant controller. Compared with the existing resonant control methods, the proposed ROVR can separate and extract the positive and negative sequence harmonics, and avoid the phase delay and peak point simultaneously. Secondly, a generalized extended state observer (GESO) is introduced to enhance the suppression of low-frequency disturbance. Then, the composite control strategy is developed. Besides, the stability, disturbance rejection performance, parameters configuration, robustness and tracking performance of the proposed ROVR-GADRC are comprehensively analyzed. The proposed current controller simultaneously performs harmonics suppression of specific phase sequence and other unknown disturbances attenuation. Finally, the feasibility and effectiveness of the proposed method is verified on a PMSM platform through the experimental results.

Observer-Based Dynamic Event-Triggered Control for Multiagent Systems With Time-Varying Delay

This article is concerned with the dynamic event-triggered-based adaptive output-feedback tracking control problem of nonlinear multiagent systems with time-varying input delay. By utilizing the approximation capability of neural network (NN), a low-gain nonlinear observer is first established to estimate the immeasurable states. To mitigate the effect of time-varying input delay, an auxiliary system with communication information is designed to generate the compensation signals. Then, a distributed adaptive composite NN dynamic surface control (DSC) strategy is proposed to acquire the satisfactory tracking accuracy, where the filter errors are compensated by the introduced serial-parallel estimation model. Moreover, an effective switching dynamic event-triggered mechanism is developed to determine the communication instants and reduce the update frequency of the controller. It is proven that the consensus tracking error converges to a residual set of the origin. Finally, simulation results are presented to demonstrate the effectiveness of the proposed composite NN DSC scheme.

Composite Control to Suppress Output Fluctuation for Receiver Side of Dynamic Wireless Power Transfer System

Mobile device charging is made possible by the dynamic wireless power transfer technology and it's developing towards higher power levels. The output power fluctuates significantly with the movement of the device due to the discontinuous coil switching and the peculiarities of the dynamic magnetic coupler, which has an impact on charging effectiveness and battery life. In this paper, a three-level Buck (Buck TL) is used as a DC-DC converter at the receiver side and a composite control aiming to suppress output power fluctuations is proposed. The minimum effective suppression range for the frequency of the coupling fluctuation and the control performance in the transient state are analyzed theoretically. Compared with PI control, the simulation is built, and the 2.6 kW experiment results showed that the composite control could reduce the system output voltage ripple from 13% to 4.4% with resistive load and the output charging current ripple from 22% to 9% with battery load without impacting the efficiency of the Buck TL system, which verified the effectiveness of the proposed composite control strategy.

Inverse-Dynamics- and disturbance-Observer-Based tube model predictive tracking control of uncertain robotic manipulator

A novel robust hierarchical multi-loop composite control scheme is proposed for the trajectory tracking control of robotic manipulators subject to constraints and disturbances. The inner loop based on inverse dynamics control is used to reduce the nonlinear tracking error system to a set of decoupled linear subsystems to alleviate the computational effort during the sequel optimization. The feasible regions of the equivalent state and control input of each subsystem can be computed efficiently by choosing an appropriate inertia matrix estimate. The external loop, relying on a set of separate disturbance-observer-based tube model predictive composite controllers, is used to robustly stabilize the decoupled subsystems. In particular, the disturbance observers are designed to compensate for the disturbances actively, while the tube model predictive controllers are used to reject the residual disturbances. The robust tightened constraints are obtained by calculating the outer-bounding-tube-type residual disturbance invariant sets of the closed-loop subsystems. Furthermore, the recursive feasibility and input-to-state stability of the closed-loop system are investigated. The effectiveness of the proposed control scheme is verified by the simulation experiment on a PUMA 560 robotic manipulator.

Finite‐time composite control for fuzzy delayed semi‐Markovian jump systems with multiple disturbances and uncertainty

SummaryThis article is concerned with the issue of finite‐time analysis for fuzzy semi‐Markovian jump systems (S‐MJSs) with multiple disturbances. Takagi–Sugeno fuzzy method is applied to address the nonlinear problem of closed‐loop systems. Unlike the existing research, delay, multiple disturbances, generally uncertain transition rate, uncertain parameters are all analyzed in a unify S‐MJSs framework. The aim of this study is to construct a composite control strategy for stable operation of S‐MJSs with multiple disturbances on the basis of the actual system requirements. For S‐MJSs, conservatism of analysis method and uncertainty of actual system are both the significant problems need to be solved urgently. First, the sufficient condition of S‐MJSs is obtained to guarantee the finite‐time stable performance through mathematical analysis and matrix inequality derivation. Second, disturbance observer based control and control are combined to deal with the effects of multiple disturbances which contain incomplete information disturbance and norm bounded disturbance. Third, fuzzy controller is designed to satisfy close‐loop systems finite‐time performance. Finally, the actual nonlinear example is presented to verify the accuracy of the approach.

Robust adaptive composite control of DC–DC boost converter with constant power load in DC microgrid

Power electronic loads are penetrating in DC microgrid. These loads are usually regarded as constant power loads (CPLs) with negative impedance characteristics, which seriously affect the dynamic performance of DC bus voltage and may result in instability of the DC microgrid system. To improve the performance and stability of a boost converter with CPL, proposed herein is a robust adaptive composite control strategy, which mainly includes two control loops. An affine nonlinear mathematical model is established. Based on the differential geometry theory, the minimum phase problem is analyzed under different output functions. In the inner control loop, the inductor current is linearized by using exact feedback linearization theory to a linear system. Meanwhile, sliding mode control method is studied to control the linear system, and an adaptive law is designed to update the sliding mode switching gain. In the outer control loop, the output voltage is regulated by proportional–integral control technology to achieve no steady-state error for the DC bus voltage. Furthermore, the robustness of the closed-loop system is verified, and the global asymptotic stability of the control system is proved. Compared with the existing method, both simulation results and experimental results verify the validity and superiority of the presented control strategy.