In this paper, we focus on the issue of adaptive fuzzy finite-time tracking control for a class of uncertain fractional-order nonlinear systems with external disturbance. A new finite-time fractional-order command filtered implementation scheme is presented for the adaptive backstepping method. In the command filtered implementation approach, analytical computation of the fractional derivatives of the stabilizing functions is not necessary. Therefore, the controller and adaptive law of the systems are easier to derive and implement. Based on the proposed command filter, adaptive backstepping technique and fractional Lyapunov’s direct method, a novel adaptive fuzzy finite-time controller is designed, which can guarantee that the tracking error converges to a small neighborhood of the origin in finite time, and other signals of the closed-loop systems are semi-global uniform ultimate bounded. In the design process of the controller, fuzzy logic systems (FLSs) are employed to approximate the unknown nonlinear functions, and an auxiliary function is adopted to compensate for the unknown external disturbance and approximation errors of FLSs. Finally, a simulation example is given to show the effectiveness and availability of the proposed control strategy.

This study presents a novel digital double‐loop control method, that is, inner current loop and outer voltage loop, for a single‐stage isolated Cuk power factor correction (PFC) converter in continuous conduction mode (CCM). First, control law of current loop, consisting of a current term and a voltage term, is derived. Considering that inductance value of inductors varies with load change, an adaptive gain scheduling method is applied to change the current term. Second, control law of voltage loop is derived based on proportional‐integral control with introducing linearisation and feedforward compensation. Meanwhile, a moving average filter is utilised to decrease ripple effect of output voltage, and thus smoother input signal for current loop and fast dynamic response for voltage loop are guaranteed. A 1600 W one‐phase isolated Cuk PFC converter controlled by a digital signal processor is developed and achieves power factor higher than 0.99, total harmonic distortion of input current lower than 8.5% with load varying from 25 to 100% and fast dynamic response performance. Finally, a 4800 W three‐phase AC–DC converter based on the above PFC converter is implemented and its performance additionally indicate that current sharing issue can be easy to deal with by using the proposed control method.

Due to underwater light absorption and scattering, underwater images often suffer from color distortion and low contrast. However, existing underwater image enhancement methods can only solve the problem of underwater image degradation in a specific scene, and do not consider the impact of dynamic changes in water depth and water quality on underwater image degradation. In order to solve the above problems, this paper proposes a multi-channel adaptive fusion underwater image enhancement algorithm. Firstly, in order to alleviate the color distortion issue caused by light attenuation, this paper proposes a gridded adaptive channel compensation algorithm. Subsequently, the compensated image is used for multi-channel image enhancement. The first channel image is the enhanced result of the compensated image using the local entropy-constrained gray world algorithm proposed in this paper and the second channel image is the enhanced result of the first channel image using the contrast limited adaptive histogram equalization(CLAHE) algorithm. Next, the saliency weight image and brightness weight image of the two-channel images are calculated respectively. Finally, in order to combine the information advantages of different channel images, this paper adopts Laplacian-Gaussian pyramid to fuse the two-channel enhanced images and their corresponding weight images to obtain the final enhanced image. Experiments on three datasets, LSUI, UIEB and RUIE, show that the underwater images processed by the algorithm proposed in this paper have a good improvement in color and contrast, and robustness is better than the comparative methods. The UIQM value of the enhanced images is 126.844% higher than the original images, the UCIQE value is 66.370% higher than the original images, and the number of ORB feature points is 95.862% higher than the original images. Results available at https://drive.google.com/file.

This paper presents an adaptive gain-scheduled backstepping control U+0028 AGSBC U+0029 scheme for the balance control of an underactuated mechanical power line inspection U+0028 PLI U+0029 robotic system with two degrees of freedom and a single control input. First, a nonlinear dynamic model of the balance adjustment process of the PLI robot is constructed, and then the model is linearized at a nominal equilibrium point to overcome the computational infeasibility of the conventional backstepping technique. Second, to solve generalized stabilization control issue for underactuated systems with multiple equilibrium points, an equilibrium manifold linearized model is developed using a scheduling variable, and then a gain-scheduled backstepping control U+0028 GSBC U+0029 scheme for expanding the operational area of the controlled system is constructed. Finally, an adaptive mechanism is proposed to counteract the impact of external disturbances. The robust stability of the closed-loop system is ensured by Lyapunov theorem. Simulation results demonstrate the effectiveness and high performance of the proposed scheme compared with other control schemes.

To overcome the difficulty in tracking the trajectory of an inspection robot inside a transformer, this paper proposes a distributed model predictive control method. First, the kinematics and dynamics models of a robot in transformer oil are established based on the Lagrange equation. Then, by using the nonlinear model predictive control method and following the distributed control theory, the motion of a robot in transformer oil is decoupled into five independent subsystems. Based on this, a distributed model predictive control (DMPC) method is then developed. Finally, the simulation results indicate that a robot motion control system based on DMPC achieves high tracking accuracy and robustness with reduced computing complexity, and it provides an effective solution for the motion control of robots in narrow environments.

To solve the trajectory planning problem of the flexible manipulator under various constraints such as end-camera attitude, drive space, and obstacles during video inspection along a continuous path in narrow three-dimensional space, this paper proposes a time-optimal trajectory planning method from the initial configuration to the final configuration. The trajectory planning problem is transformed into a multi-constraint optimization problem. First, to realize continuous video inspection in an unstructured complex environment, by analyzing the geometric model of the two-segment flexible manipulator with a camera at the end, the pose constraints between the camera and the shooting surface are formulated by the space vector method, the driving constraints are formulated based on kinematics, and the obstacle constraints are formulated by space mapping. Then, a multi-constraint optimization model is constructed to generate the smooth trajectory of the drive cable of the flexible manipulator by minimizing the total time of continuous path motion. Compared with the conventional point-to-point collision avoidance planning solution method, this paper starts from the global perspective and investigates the less considered continuous path trajectory planning problem; also, the swarm intelligence algorithm artificial jellyfish search algorithm (JS) is employed to optimize the solution and find the minimum time trajectory conforming to a variety of complex constraints. Finally, a simulation is conducted with CoppeliaSim, and the continuous path video inspection experiment is carried out in the 500KV GIS (Gas Insulated Switchgear) equipment, the simulation and experimental results indicate that the planned drive cable trajectory is smooth and effective. In addition, each path point is tracked and obstacles are avoided safely. When the flexible manipulator moves along the whole path, the pose of the camera satisfies the relaxed attitude constrain The proposed method can guide the two-segment flexible manipulator to complete the continuous video inspection task of the GIS cavity wall and conductive column surface.