Seeker-M: A bionic mantis shrimp robot with an adjustable-mass flexible spine.

This paper presents a UAV-based building crack real-time detection system that integrates an improved YOLOv8 algorithm with Linear Active Disturbance Rejection Control (LADRC). The system is equipped with a high-resolution camera and sensors to capture high-definition images and height information. First, a trajectory tracking controller based on LADRC was designed for the UAV, which uses a linear extended state observer to estimate and compensate for unknown disturbances such as wind interference, significantly enhancing the flight stability of the UAV in complex environments and ensuring stable crack image acquisition. Secondly, we integrated Convolutional Block Attention Module (CBAM) into the YOLOv8 model, dynamically enhancing crack feature extraction through both channel and spatial attention mechanisms, thereby improving recognition robustness in complex backgrounds. Lastly, a skeleton extraction algorithm was applied for the secondary processing of the segmented cracks, enabling precise calculations of crack length and average width and outputting the results to a user interface for visualization. The experimental results demonstrate that the system successfully identifies and extracts crack regions, accurately calculates crack dimensions, and enables real-time monitoring through high-speed data transmission to the ground station. Compared to traditional manual inspection methods, the system significantly improves detection efficiency while maintaining high accuracy and reliability.

The frequency regulation has become one of the major subjects in microgrid power system due to the complexity structure of microgrid. In order to solve this problem, this paper proposes an improved linear active disturbance rejection control algorithm (ILADRC) that can significantly improve system performances through changing feedback control law to reduce the disturbance estimation error of extended state observer. Then, the proposed algorithm is employed in microgrid power system frequency regulation problem, which demonstrates its effectiveness. The parameters of controllers are optimized by particle swarm optimization (PSO) algorithm improved by genetic algorithm (GA). Simulations with different disturbances including sudden and stochastic change of load demand and wind turbine generation are carried out in comparison with previous studies. And robustness testing based on Monte-Carlo approach also shows better performance. So frequency stability of microgrid power system can be well guaranteed by proposed control algorithm.

Permanent magnet synchronous motor (PMSM) is widely used in aerospace, new energy electric vehicles and other fields. In order to solve the problems of poor parameter adaptability and poor disturbance resistance in the PMSM speed control system with traditional PI control algorithm, a linear active disturbance rejection control (LADRC) algorithm for PMSM is proposed in this paper. Then, the physical meaning of each parameter in LADRC and the setting scheme are summarized according to the phenomena encountered in the experimental. Simulation and experiment show that the proposed scheme can improve the robustness of PMSM speed control system.

The Pointing Acquisition Tracking (PAT) technology, as a powerful guarantee for fast establishment and stable communication of wireless laser communication links, is the key to improve the practicality of shipboard wireless laser communication. In this paper, the initial pointing method of the shipboard laser communication terminal is designed by using the position and attitude information obtained from the GPS/INS module. Since the system optical relationship varies with the coarse tracking mechanism attitude during tracking, the optical decoupling model from the coarse tracking mechanism to the CMOS detector is measured using the optical matrix method. On this basis, the robust linear active disturbance rejection control (LADRC) algorithm is used for spot tracking. Designing the acquisition and tracking experiment of maritime laser communication, using the initial pointing algorithm to obtain the initial pointing angle of the antenna boresight and successfully capture the beacon light. Experiments show that the tracking peak error of coarse tracking is around 40urad, and the standard deviation is below 20urad. the tracking peak error of fine tracking is around 15urad, and the standard deviation is below 10urad. The experimental data show that the tracking algorithm meets the requirements of stable, reliable and high-precision tracking.

Self-tuning Control of Manipulator Based on Fuzzy Linear Active Disturbance Rejection Control and Particle Swarm Optimization Algorithm

Nonlinear active disturbance rejection control is much more effective than linear active disturbance rejection control in tolerance to uncertainties and disturbances. However, it brings a great challenge for theoretical analysis, especially the stability analysis. This article proposes a linear matrix inequality method to analyze the absolute stability of generalized nonlinear active disturbance rejection control form which contains multiple nonlinearities with different parameters in both extended state observer and control law for single-input single-output systems. The generalized nonlinear active disturbance rejection control algorithm and the single-input single-output system are transformed into a direct multiple-input multiple-output Lurie system. A sufficient condition to determine its absolute stability based on linear matrix inequality method is given. The Lyapunov function of the Lurie system exists when the group of linear matrix inequalities is feasible. The free parameters and coefficients in Lyapunov function are given by the solution of these linear matrix inequalities. The electromagnetic valve actuator system in camless engine is presented as an application to illustrate how to perform the proposed method for absolute stability analysis and the stable region of parameter perturbations is obtained via the method. Simulation results show that the linear matrix inequality–based method is convenient and effective to determine whether the closed-loop system is absolutely stable.

In this paper, the problem of maximizing energy yield from the available wind is addressed by using a robust Proportional-Derivative (PD) controller in combination with a Linear Active Disturbance Rejection Control (LADRC) approach. Firstly, the theory of the Wind Turbine (WT) pitch control algorithms is analysed and then based on the analysis, 1.5 MW WT model with a Servo System (SS) and Doubly Fed Induction Generator (DFIG) is developed. The blade pitch angle (R) is controlled to ensure that the variable speed WT system operate safely and the optimum power is achieved. Developed LADRC algorithm reveal dynamic performance of the blade pitch angle, rotor speed and rated power characteristics. Within the wind turbine standard operating regimes, controllers have shown promising results. Proposed LADRC technique validates superior performance. Finally, MATLAB/SIMULINK tool box establishes the corresponding model to simulation test in order to verify the effectiveness and correctness of the analysed algorithms. Simulation result demonstrates that the developed pitch servo control system has good dynamic, steady state performance and robustness.

Inspired by the agility of mantis shrimp, this paper presents the development of a novel bionic mantis shrimp robot with multiple pleopods coupled motion for underwater target recognition and tracking. Firstly, the novel bionic robot is constructed based on the inspiration from biological mantis shrimp. Secondly, a Kalman filter-based algorithm, namely MobileNet-YOLO (KMY), is created to collect datasets and train neural networks. Thirdly, a moving target following system is developed for the bionic mantis shrimp robot, in which a dual PID controller is used to track underwater moving targets. The real robot testing results show that the proposed control system can enable our bionic robot to follow a specific moving target in a narrow pool (2m × 1m × 1m), and the minimum turning radius can be up to 0.55m when the angle between the robot's initial motion and the motion of target is 90°.

Powered parafoils, known for their impressive load-bearing capacity and extended endurance, have garnered significant interest. However, the parafoil system is a highly complex nonlinear system. It primarily relies on the steering gear to change flight direction and utilizes a thrust motor for climbing. However, achieving precise trajectory tracking control presents a challenge due to the interdependence of direction and altitude control. Furthermore, underactuation and wind disturbances bring additional difficulties for trajectory tracking control. Consequently, realizing trajectory tracking control for powered parafoils holds immense significance. In this paper, we propose a trajectory tracking method based on Twin Delayed Deep Deterministic Policy Gradient (TD3) algorithm-optimized Linear Active Disturbance Rejection Control (LADRC). Our method addresses the underactuation issue by incorporating a guiding law while utilizing two LADRC methods to achieve decoupling and compensate for disturbances. Moreover, we employ the TD3 algorithm to dynamically adjust controller parameters, thus enhancing the controller performance. The simulation results demonstrate the effectiveness of our proposed method as a trajectory tracking control approach. Additionally, since the control process is not reliant on system-specific models, our method can also provide guidance for trajectory tracking control in other aircraft.

In this study, pitch angle control is employed to maintain the output power and the rotor speed of the wind turbine, whenever the wind speed is higher than the base wind speed. Blade pitch is a key part of a wind turbine and it is a complex nonlinear system interrupted by many uncertainties. The proposed controller linear active disturbance rejection control is utilized to control the output power and rotor speed of the wind turbine. LADRC is based on the extended state observer and a proportional derivative control law. The distinguished feature of the LADRC is, that it can estimate the internal and external disturbances and to compensate for it in real time. The other advantage of the LADRC controller is that only two parameters need to be tuned: observer bandwidth and controller bandwidth. The purpose of the proposed pitch angle Control is to regulate the pitch angle of the wind turbine with respect to wind speed to improve the efficiency of the wind turbine and overcome the safety issues. To validate the effectiveness and superiority of the proposed controller, the results are compared with the conventional PD and Fuzzy logic controller. The simulation results show that the LADRC controller is better in performance as compared to the conventional PD and FLPI controller.

There exists a steady-state error in the closed-loop system output with some conventional linear active rejection control approaches when the pitch channel control variable of the near space vehicle is the angle of attack. In this study, a cascaded linear active disturbance rejection control approach based on the cascaded control idea is proposed. Both the inner-loop controller and the outer-loop controller are designed by the linear active disturbance rejection control method. The inner-loop is built by angular rate feedback to improve dynamic performance of the closed-loop system, and the outer-loop is built by angle of attack feedback to remove the undesired steady-state error. The approach is employed to a hypersonic near space vehicle autopilot. The numerical simulations show that the proposed approach preserves the performances on time domain and frequency domain as good as those of the conventional active disturbance rejection control approaches, and it has the better performances on disturbance rejection and angle of attack command tracking accuracy than those of some previous active disturbance rejection control approaches.

To solve the taxiing control problem under lack of nose wheel steering system and rudder, a control approach which uses differential propeller thrust to control taxiing is proposed, with full-wing solar-powered UAV (FSUAV) as the research model. This study gives the taxiing mathematical model of FSUAV and designs a taxiing controller based on linear active disturbance rejection control method (LADRC). Simulations are conducted to demonstrate the effectiveness and robustness of the designed controller and compare with PID controller.

In order to improve the temperature control effect of nonlinear, large time-delay and inertia space environment simulation equipment, and to solve the contradiction between heating rapidity and overshoot, this paper introduces the Active Disturbance Rejection Control algorithm into space environment simulation temperature control. Based on the platform model, Active Disturbance Rejection Control controller was designed, and the cascade control model of the heat sink gas-nitrogen temperature space environment simulation equipment was established. The cascade control system was simulated on the MATLAB software platform, and the specimen was raised from 0 °C to 100 °C. The step response rise time was about 4000 s. The specimen rise temperature rate is about 1.5°C/min, and the temperature control process is smooth and there is no overshoot. The simulation shows that the Active Disturbance Rejection Control can effectively improve the space environment simulation temperature control effect.

ABSTRACTOffshore wind energy is gaining significant global attention, making it essential to accurately predict potential faults in offshore wind turbines (OWTs) to ensure the stability of power grid operations. The pitch control system is a critical component that governs two key parameters: the blade twist angle and the pitch angle. The pitch angle, being dynamic, serves as a sensitive indicator for detecting subtle variations in blade orientation, which can reveal potential faults that may not be evident in the blade twist angle. This paper presents a three‐stage, data‐driven methodology for detecting potential failures in the pitch control system of specific 7 MW OWTs through dynamic pitch angle analysis. Stage 1 involves preprocessing raw supervisory control and data acquisition (SCADA) data, which includes anomaly detection and feature extraction. This process filters out obvious anomalies before training the model. Stage 2 involves developing a pitch angle prediction model that utilizes the relevant features identified in Stage 1 to forecast the pitch angle within a specified time interval. This model aims to accurately reflect the optimal operating conditions of the wind turbine by excluding data related to target faults. Stage 3 integrates the predicted pitch angles from Stage 2, which are dynamic parameters, along with selected features from Stage 1, into a model for predicting alarm signals. This model is designed to generate alarm signals for potential faults in the targeted OWT. Comparisons with six other sequential models demonstrate a higher accuracy, while reducing the number of feature extraction parameters. This indicates that the method can efficiently identify potential faults within the pitch control system by utilizing dynamic pitch angle parameters.

Gas flow facilities are essential to test gas flow sensors, meters and other devices. Pressure control is a key problem in particular for high pressure gas flow facilities. An appropriate control scheme is critical to improve the stability and the speed of the pressure control. This paper presents a linear Active Disturbance Rejection Control (ADRC) scheme for high pressure gas flow facilities with closed-loop pipelines. The control model of the flow facility is identified by a step response method. A reduced-order linear expansion state observer and a related control law are designed to estimate and compensate the total disturbance of the system. The robustness of the ADRC algorithm is compared with a PID control algorithm by Monte Carlo simulation. Control speed and disturbance rejection ability of ADRC are also compared with PID through simulation and gas flow experiments. The results show that, compared with PID, ADRC has a shorter settling time, stronger disturbance rejecting capability and more robust performance. The improved pressure stability has been proved to be beneficial to test gas flow sensors in the facility.