A Novel Smith Predictive Linear Active Disturbance Rejection Control Strategy for the First-Order Time-Delay Inertial System

The series manipulator of the demolition robot has different working postures and large self-weight so that the bearing mass of the joint hydraulic cylinder is a variable value, and the change of mass affects the dynamic characteristics of the valve-controlled hydraulic cylinder system. In this paper, an equivalent mass estimation method of the big-arm joint hydraulic cylinder is given, and the natural frequency range of the big-arm hydraulic cylinder-load system is calculated. In order to suppress the influence of the change of the natural frequency and external disturbance of the hydraulic cylinder on the system, the linear active disturbance rejection control is adopted in the closed-loop position control. The simulation results show that the change of load mass of the joint hydraulic cannot be ignored when designing the joint position controller of multi-joint hydraulic manipulator. And the simulation tests prove that the linear active disturbance rejection control strategy keeps good dynamic characteristic and steady-state accuracy for the change of natural frequency and external disturbance of hydraulic cylinder and has good tracking performance for periodic sinusoidal signal. Linear active disturbance rejection control is robust in the variable mass control of the manipulator and meets the requirements of the joint position control of the heavy-duty hydraulic manipulator.

In order to improve the grid-connected stability of wind power grid-connected inverter, solve the harmonic and resonance problems encountered at the grid-connected interface of inverter when the load jumps. An improved linear active disturbance rejection control strategy combined with active damping (ILADRC-AD) is designed. Firstly, the mathematical model of inductance-capacitance-inductance (LCL) inverter is established, and the principle of traditional third order active disturbance rejection controller is analyzed. Based on the idea of lead correction, an improved LADRC is designed by series lead correction links on the total disturbance channel of the linear extended state observer (LESO). Capacitive current feedback active damping is introduced in combination with improved LADRC to generate an ILADRC-AD control strategy. The stability and robustness of the system are effectively improved. Finally, the frequency characteristics of the ILADRC-AD inverter system are analyzed by frequency domain analysis method, and the MATLAB simulation comparison of improved control and traditional PI and LADRC the grid current waveform. The results show that the improved control not only has more stable grid-connected current, but also has fast dynamic response and strong harmonic suppression when the load fluctuates.

Remotely operated vehicles (ROVs) face challenges in achieving optimal trajectory tracking performance during underwater movement due to external disturbances and parameter uncertainties. To address this issue, this paper proposes a position and attitude control strategy for underwater robots based on a reinforcement learning active disturbance rejection controller. The linear active disturbance rejection controller has achieved satisfactory results in the field of underwater robot control. However, fixed-parameter controllers cannot achieve optimal control performance for the controlled object. Therefore, further exploration of the adaptive capability of control parameters based on the linear active disturbance rejection controller was conducted. The deep deterministic policy gradient (DDPG) algorithm was used to optimize the linear extended state observer (LESO). This strategy employs deep neural networks to adjust the LESO parameters online based on measured states, allowing for more accurate estimation of model uncertainties and environmental disturbances, and compensating the total disturbance into the control input online, resulting in better disturbance estimation and control performance. Simulation results show that the proposed control scheme, compared to PID and fixed parameter LADRC, as well as the double closed-loop sliding mode control method based on nonlinear observers (NESO-DSMC), significantly improves the disturbance estimation accuracy of the linear active disturbance rejection controller, leading to higher control precision and stronger robustness, thus demonstrating the effectiveness of the proposed control strategy.

This paper investigates the design problem of the attitude controller for air-breathing supersonic vehicle subject to uncertainties and disturbances. Firstly, the longitudinal model is established for the attitude controller design which is devised as a strict feedback formulation, and a transformed tracking error is derived with the prescribed performance control technique such that it can limit the tracking error to a predefined region. Then, a novel linear active disturbance rejection control scheme is proposed for the attitude system to enhance the steady-state and transient-state performances by incorporating the transformed tracking error. On the basis of the Lyapunov stability theorem, the convergence and stability characteristics are both rigorously proved for the closed-loop system. Finally, extensive contrast simulations are conducted to demonstrate the effectiveness, robustness, and advantage of the proposed control strategy.

Hydrogen energy storage systems are becoming increasingly accepted owing to their environmental friendliness. The efficiency and performance of these systems largely depend on the attributes of their power electronic interface systems. Among the promising solutions is a multiport-isolated DC-DC converter with characteristics of reduced component count, fewer conversion stages, and galvanic isolation. However, this system presents a challenge due to its inherent cross-coupling effect, complicating precise control. To address this, linear active disturbance rejection control (LADRC) is a viable option, leveraging dynamic/disturbance properties observed by linear extended state observers. LADRC serves as a decoupling controller, mitigating the cross-coupling effect. However, LADRC has several gains, and selecting them can be a difficult task, often requiring manual tuning. To streamline this process, this paper proposes utilising particle swarm optimisation to determine the optimum gains of LADRC. By employing this approach, the implementation of LADRC is facilitated with reduced design efforts while ensuring effective decoupling control within the system. Simulations are conducted to validate the performance of the optimised gain LADRC.

The dual observation of periodic and aperiodic interferences cannot be balanced by traditional linear extended state observer (T-LESO). Therefore, the speed fluctuations caused by uncertain periodic and aperiodic interferences in the interior permanent magnet synchronous motor control system cannot be suppressed by the traditional linear active disturbance rejection controller. To resolve the aforementioned problem, an improved linear active disturbance rejection controller (I-LADRC) in which multifrequency quasi-resonant filtering decoupling linear extended state observer and generalized linear extended state observer (G-LESO) are cascaded is proposed. In this controller, the interference feedforward control method of T-LESO is first changed, the observer bandwidth <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ω_o</i> and controller bandwidth <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ω_c</i> in the transfer function based on the interference term are decoupled from each other, reducing the difficulty of parameter tuning. On this basis, a multifrequency quasi-resonant filter is embedded in the decoupled linear extended state observer (LESO), so that periodic interferences can be accurately observed. For G-LESO, a fourth-order LESO is adopted to enable more accurate observation of aperiodic high-order interferences. The outer loop controller based on I-LADRC is designed, and the correctness and effectiveness of this method are verified through experiments.

The paper applies wavelet de-noising in linear active disturbance rejection control (LADRC). To decrease the noise in real time, the method of sliding window is designed. When the frequency and intensity of disturbance noise in the system are large, the control effect of LADRC will be reduced greatly. To solve that, the real-time de-noising algorithm is concatenated between the noisy output and the linear extended state observer (LESO). The results of simulations show that, in LADRC, the applied real-time de-noising algorithm is effective.

This paper presents a robustness study of a Linear Active Disturbance Rejection Control (LADRC) framework. A dynamic simulative study is carried out on a two-wheeled differential drive mobile robot (DDMR) velocity control. A dynamic model of the robot with actuators has been considered, including uncertain parameters and a coupling between the linear and angular velocities, and the two angular velocities, the robot motion is also a subject of external disturbances which can degrade the performance of classical controllers. However, In LADRC, the unmeasured dynamics and external disturbances are considered as an additional state variable, it is then estimated by a linear Extended State Observer (LESO) and compensated in the control law. The simulation results show the efficiency of proposed LADRC-based controller in the reduction of the effect of dynamic variations. The LADRC robustness is compared with a proportional-integral-derivative controller (PID). Better results in terms of disturbance rejection have been reported for the LADRC.

It is difficult to establish an exact mathematical model for the induction motor and the robustness is poor of the vector control system using PI regulator. This paper adopts the linear active disturbance rejection controller (LADRC) to control inductor motor. LADRC doesn't need the exact mathematical model of motor and it can not only estimate but also compensate the general disturbance that includes the coupling items in model of motor and parameters perturbations by linear extended state observer (LESO), so the rotor flux and torque fully decouple. As a result, the performance is improved. To prove the above control scheme, the proposed control system has been simulated in MATLAB/SIMULINK, and the comparison was made with PID. Simulation results show that LADRC has better performance and robustness than PID.

Aiming at the problem of anti-swing and positioning of underactuated crane, this paper proposes a control strategy of underactuated bridge crane based on Linear Active Disturbance Rejection Control and controller parameter optimization method. Distinguished from other conventional control strategies of bridge crane, this method does not require any approximate decoupling or linearization of the crane model and allows the model to have some certain uncertainty, friction and air resistance of the system are also considered. At the same time, for the parameter tuning problem of the sensors, the bird swarm optimization algorithm is applied to optimize the parameters. And the excellent control performance of this method has been proved by simulation.

This paper proposes a novel control strategy integrating active rectification and Linear Active Disturbance Rejection Control (LADRC) for constant-current output in LCC-LCC compensated Electric Vehicle Dynamic Wireless Power Transfer (EV-DWPT) systems. To address power fluctuations caused by coupling variations during dynamic operation, a synchronous phase-locking strategy based on active/reactive power is implemented on the secondary side. The LADRC controller, designed for its simplicity, low model dependence, and strong robustness, is discretized using the bilinear transformation method. Simulations demonstrate that compared to PI control, the proposed LADRC achieves faster response, minimal overshoot during reference current changes (e.g., 20A to 10A), and superior disturbance rejection across the full dynamic operating range—effectively suppressing power fluctuations without requiring primary-secondary communication.

To improve the robustness and the anti-disturbance of control system, regulate its stiffness, a scheme concluding linear active disturbance rejection controllers for pneumatic servo system is proposed. Two linear active disturbance rejection controllers are designed respectively to track the motion and pressure reference. The design of a linear active disturbance rejection controller is independent of precisely mathematical model of the system. The extended state observer can track successfully the states and extended state of the system, and it is possible to realize the states feedback and handle the model uncertainty and compensate external disturbance. The simulation results show that pneumatic servo system based on linear active disturbance rejection controllers is robust against modeling uncertainty and external disturbances. The dynamic performance of the system using linear active disturbance rejection controllers also can be improved as well.

During orbital maneuvers, spacecraft attitude control is subjected to complex internal and external disturbances caused by factors such as thruster misalignment and mass uncertainties. In this paper, a rigid-flexible coupling dynamic model is developed, incorporating rigid-body translation, attitude rotation, and flexible solar-panel vibrations. A linear active disturbance rejection controller (LADRC), constructed on the basis of a linear extended state observer (LESO), is then designed. By analyzing the frequency-domain characteristics of the LESO, the influence of observer bandwidth on disturbance estimation is clarified. Simulation results show that, compared with conventional PID control, the proposed LADRC achieves faster attitude-error convergence under thrust-eccentric disturbances, significantly improving attitude stability and disturbance-rejection performance during orbital maneuvers.

This paper takes the single-phase off-grid inverter as the research object, proposes a linear active disturbance rejection control (LADRC) strategy, and conducts discretization processing. Firstly, a mathematical model of the single-phase off-grid inverter is established, and a state-space model is constructed. Then, according to the state-space model, a continuous-domain LADRC controller is designed. Subsequently, the current Euler method and the current zero-order hold(ZOH) method are respectively employed to discretize the controller. Finally, through Matlab/Simulink simulation, the performances of the two discretization methods in terms of total harmonic distortion(THD), output voltage error, etc., under different operating conditions are compared, which provides a reference for practical engineering applications.

LLC resonant converter, which is widely used in the charging of new energy vehicles, can achieve zero-voltage switching (ZVS) of the primary side MOSFET and zero-current switching (ZCS) of the secondary side rectifying diode. They also have the advantages of high efficiency and high-power density. The output voltage is still affected by input voltage fluctuation, reference voltage change, load mutation and other factors. The charging mode of automobile batteries with different materials is also different. In order to stabilize the output voltage and realize automatic switching of constant voltage and current, this paper proposes a double closed-loop linear active disturbance rejection control (LADRC) scheme. Firstly, the transfer functions of the system are obtained by extended description function (EDF) method and simulation method respectively. The transfer functions of the two methods are compared and analysed. Finally, the LADRC controller and PI controller are simulated and compared, and the dynamic performance of the control system is evaluated by ITAE index. The experimental results show that the output voltage of LADRC control is more stable.