S-plane Controller Research Articles

Tracking control of AUV via novel soft actor-critic and suboptimal demonstrations

Tracking control for autonomous underwater vehicles (AUVs) faces multifaceted challenges, making the acquisition of optimal demonstrations a daunting task. The suboptimal demonstrations mean less tracking accuracy. To address the issue of learning from suboptimal demonstrations, this paper proposes a model-free reinforcement learning (RL) method. Our approach utilizes suboptimal demonstrations to obtain an initial controller, which is iteratively refined during training. Given the suboptimal characteristics, demonstrations will be removed from the replay buffer upon reaching capacity. Building upon the soft actor-critic (SAC), our approach integrates a Recurrent Neural Network (RNN) into the policy network to capture the relationship between states and actions. Moreover, we introduce logarithmic and cosine functions to the reward function for enhancing the training effectiveness. Finally, we validate the effectiveness of the proposed Initialize Controller from Demonstrations (ICfD) algorithm through simulations with two reference trajectories. We provide a definition for tracking success. The success rates of ICfD in the two reference trajectories are 95.60% and 94.05%, respectively, surpassing the state-of-the-art RL method SACfD (80.03% 90.55%). The average one-step distance errors of ICfD are 1.20 m and 0.76 m, respectively, significantly lower than the S-plane controller (9.725 m 8.325 m). Besides, we evaluate the generalization of the ICfD controller in different scenarios.

Design and Verification of Deep Submergence Rescue Vehicle Motion Control System.

A six degree-of-freedom (DOF) motion control system for docking with a deep submergence rescue vehicle (DSRV) test platform was the focus of this study. The existing control methods can meet the general requirements of underwater operations, but the complex structures or multiple parameters of some methods have prevented them from widespread use. The majority of the existing methods assume the heeling effect to be negligible and ignore it, achieving motion control in only four or five DOFs. In view of the demanding requirements regarding positions and inclinations in six DOFs during the docking process, the software and hardware architectures of the DSRV platform were constructed, and then sparse filtering technology was introduced for data smoothing. Based on the adaptive control strategy and with a consideration of residual static loads, an improved S-plane control method was developed. By converting the force (moment) calculated by the controller to the body coordinate system, the complexity of thrust allocation was effectively reduced, and the challenge of thrust allocation in the case of a high inclination during dynamic positioning was solved accordingly. The automatic control of the trimming angle and heeling angle was realized with the linkage system of the ballast tank and pump valve. A PID method based on an intelligent integral was proposed, which not only dealt with the integral "saturation" problem, but also reduced the steady-state error and overshooting. Water pool experiments and sea trials were carried out in the presence of water currents for six-DOF motion control. The responsiveness and precision of the control system were verified by the pool experiment and sea trial results and could meet the control requirements in engineering practice. The reliability and operational stability of the proposed control system were also verified in a long-distance cruise.

Trajectory Tracking Control of Quadrotor Based on Fractional-Order S-Plane Model

Quadrotors possess traits such as under-actuation, nonlinearity, and strong coupling. Quaternions are primarily used for attitude calculations in drones, with error quaternions seldom being employed directly in the control of specific quadcopter drones. This paper focuses on the low tracking accuracy and weak anti-interference ability of quadcopter drones in trajectory-tracking control. By establishing the quadcopter quaternion model, a controller based on quaternion error is designed through a combination of fractional-order PID control with S-plane control. Trajectory-tracking experiments demonstrate that, in comparison with fractional-order PID, this method exhibits strong wind disturbance resistance and high tracking accuracy.

Path-Following Control of Small Fixed-Wing UAVs under Wind Disturbance

Aiming at the problems of low following accuracy and weak anti-disturbance ability in the three-dimensional path-following control of small fixed-wing Unmanned Aerial Vehicles (UAV), a Globally Stable Integral Sliding Mode Radial Basis Function S-Plane (GSISM+RBF S-Plane) controller is designed. The controller adopts the inner and outer loop mode, the outer loop adopts the Globally Stable Integral Sliding Mode (GSISM) control, and the inner loop adopts the S-Plane control. At the same time, the unknown disturbance in the model is estimated via an RBF neural network. Firstly, the outer loop controller is designed based on the GSISM, and its stability is proved using the Lyapunov theory. Then, the S-Plane controller is designed for the instruction signal of the inner loop. Considering the complexity of the derivation in the S-Plane controller, a second-order differentiator is introduced. Finally, considering the problem of external wind disturbance, the controller is modeled, studied, and processed in order to better reflect the impact of real external wind on UAV path following. Finally, the Globally Stable Sliding Mode (GSSM) control and Globally Stable Integral Sliding Mode S-Plane (GSISM S-Plane) control are used for a comparative experiment. The simulation results show that the designed GSISM+RBF S-Plane controller can accurately track the ideal path compared with the GSSM and GSISM S-Plane controller, and it has good control performance and anti-disturbance performance.

An Improved S-Plane Controller for High-Speed Multi-Purpose AUVs with Situational Static Loads

The classic S-plane control method combines PD structure with fuzzy control theory, with the advantages of a simple control structure and fewer parameters to be adjusted. It has been proved as a practical method in an autonomous underwater vehicle (AUV) motion control at low and medium speeds, but it takes no account of the situational static load and varying hydrodynamic forces which influence the control quality and even result in a “dolphin effect” at the time of high-speed movement. For this reason, an improved S-plane controller is designed based on the sliding mode variable structure, sliding mode surface, and control items in order to respond to the situational static load and high-speed movement. The improved S-plane controller is verified by Lyapunov stability analysis. The thrust allocation strategies are also discussed with constraints introduced in accordance with task requirements. In order to verify the practicability and effectiveness of the improved S-plane controller, both simulation experiments and field trials of AUV motion control, long-range cruise, and path point following were carried out. The results have demonstrated the superiority of the improved S-plane controller over the classic S-plane controller.

Depth and Heading Control of a Manta Robot Based on S-Plane Control

Bionic underwater robots have many advantages such as high mobility, high efficiency, high affinity, etc. They are especially suitable for tasks such as collecting hydrographic information and for detailed surveys of the marine environment. These tasks are based on their high-precision attitude control. Therefore, this paper proposes a control scheme for a bionic underwater robot—a manta robot. To improve the depth retention capability of the manta robot, a S-plane controller based on asymmetric output was designed in combination with the longitudinal motion characteristics of the manta robot. In addition, to achieve good motion control for the manta robot under conditions of large changes in the heading angle, the fuzzy controller and the heading transition target value function were combined to design the heading controller of the manta robot. Finally, the feasibility and reliability of the control system of the manta robot were verified by pool experiments. The experimental results showed that the depth control error was within ±5 cm and the heading control error was within ±5 degrees. The control scheme proposed in this paper achieves high-precision attitude control of the manta robot, providing a basis for the practical application of the manta robot.

A Sigmoid-plane adaptive control algorithm for unmanned surface vessel considering marine environment interference

This article presents an application of a Sigmoid-plane (S-plane) adaptive control algorithm to an automatic steering system in the presence of uncertain parametric of the unmanned surface vessel (USV) and the unknown disturbance of the marine environment. Due to technical difficulties such as sensor noise, the marine environment disturbance is assumed to be unmeasured. To overcome this problem, an S-plane control is designed to resist marine environment disturbances by the improved adaptive term. Based on the gradient method, the USV heading model reference adaptive controller of the USV is designed, so that the USV has a certain ability to resist model parameter changes. Considering the uncertainty of marine environment interference, a model-reference-based S-plane adaptive controller for the USV is designed. After the reference of the USV course model, the S-plane adaptive control approach is employed to reduce the effect of the marine environment. It is proved that the USV course control system is stable, despite the adverse bad sea conditions. Finally, the course control simulation experiment for the USV with the unknown marine environmental interference is carried out. To demonstrate the benefits of the S-plane adaptive controller, the results are presented in comparison with a Lyapunov method controller. The results show that the S-plane adaptive controller is robust to the changed model parameter and external disturbances.

Experimental and numerical investigation on control strategies for heave and pitch motion reduction of a catamaran

In this study, simulations and experiments were conducted on reducing the heave and pitch motions of a catamaran. To serve as stability appendages, an actively controlled T-foil and flap were designed, including their dimensions and installation position on the catamaran. Based on the uncoupled analysis of the appendages, the following control strategies were adopted: the previously proposed resultant force and moment distribution with feedback by displacement (RFMD-D) and the newly developed resultant force and moment distribution with feedback by velocity (RFMD-V). These two control strategies were applied to an S-plane controller, and their performances were tested in simulations and experiments. Finally, a bare catamaran and catamaran with actively controlled appendages were towed in a towing tank, and the two control strategies were tested. The results showed that both control strategies are effective and that RFMD-V is more effective than RFMD-D.

The Motion Controller Based on Neural Network S-Plane Model for Fixed-Wing UAVs

Aiming at the attitude control problem of fixed wing UAV, this paper introduces S-plane control, which has good control effect in the field of underwater UAV, into the attitude control of UAV. At the same time, aiming at the problem that the coefficient setting of parameters in S-plane control completely depends on experience and cannot be adjusted adaptively, the radial basis function neural network (RBFNN) is introduced, and a neural network S-plane control model which can realize on-line adaptive adjustment of the coefficient of parameters in S-plane control is proposed. The simulation results based on the data of a certain UAV show that compared with the S-plane control, the proposed neural network S-plane control model has the characteristics of fast response speed, strong anti-interference ability, and strong robustness. In addition, it also has the function of adaptive adjustment, which shows good control performance.

Energy-saving control of long-range autonomous underwater vehicle vertical plane based on human simulating intelligent control method

The long-range autonomous underwater vehicle is a new underwater vehicle with capability of stereoscopic observation of the ocean over a wide range of time series. This article proposed a novel control strategy for the long-range autonomous underwater vehicle considering the energy consumption. The vertical motion model of long-range autonomous underwater vehicle and the mathematical model of energy consumption of motion actuators are established in this article, and the maneuverability simulation experiments were carried out to analyze its motion and energy consumption characteristics. A hybrid controller based on human simulating intelligent control and S-plane control is designed. Considering the moment caused by the asymmetry of the hull in motion, an adaptive dynamic control allocation strategy is designed. Simulation experiments are conducted to demonstrate the performance of the scheme proposed.

Design and Experiment of a Plateau Data-Gathering AUV

The design, control, and implementation of an autonomous underwater vehicle (AUV) for collecting hydrological information from plateau rivers and lakes are presented in this paper. The hardware and software structures of the control system were previously described. A novel sliding mode controller (SMC) with combinational reaching law of vertical hovering motion is proposed to improve the robustness and stability. The S-plane control, a nonlinear controller with little parameters, is used in the horizontal motion. Besides, the navigation strategy based on the dead-reckoning algorithm, a path tracking based on the light-of-sight (LOS) algorithm, and a control allocation strategy considering saturation are present. Finally, experiments were performed in a tank and in a river in the Qinghai–Tibet Plateau to prove the feasibility and reliability of the AUV system.

Robust $H_{\infty}$ /S-plane Controller of Longitudinal Control for UAVs

In order to resolve the external disturbances and model parameters uncertainty during the unmanned aerial vehicles flight process, in this paper, we designed the H ∞ /S-plane controller for longitudinal control of unmanned aerial vehicles (UAVs). The S-plane control model with strong nonlinearity was used as the outer loop controller and the robust Hoc control algorithm with strong robustness was used as the inner loop controller. The effectiveness of the H ∞ /S-plane controller in the longitudinal control of unmanned aerial vehicles without external interference, with external interference and parameter perturbation, was simulated by a certain UAVs nominal model. The results showed that compared with H ∞ /PD controller and PID controller, H ∞ /S-plane controller has faster response speed and stronger anti-interference ability. So H ∞ /S-plane controller is more suitable for the longitudinal control of unmanned aerial vehicles than H ∞ /PD controller and PID controller.

Intelligent S-Plane Controller for Micro Unmanned Aerial Vehicle

Aimed at the problem of controlling the motion of micro unmanned aerial vehicles (MUAVs), an S-plane controller with good non-linear control performance is introduced that uses intelligent control ideas to achieve adaptive adjustment of the parameters of the S-plane controller. Based on the proposed controller, a motion control system for MUAVs is designed. Simulation and field tests show that the proposed intelligent S-plane controller has good control accuracy, response speed, and adaptability to environmental interference, which makes it suitable for controlling the motion of MUAVs.

A Parallel Hybrid Controller based on the Backstepping Method and S-plane Control for Three-dimensional Tracking of a Semi-pelagic Trawl System

A Parallel Hybrid Controller based on the Backstepping Method and S-plane Control for Three-dimensional Tracking of a Semi-pelagic Trawl System

Research on Motion Control of AUV with Hybrid Actuators

A switch function is presented to smooth control instructions and avoid system vibration during switch operating underwater vehicles with hybrid actuators. And a Modified S-plane Controller (MSC) is proposed by analyzing underwater vehicles dynamics and taking static force and coupling effects between the longitude velocity and other dimensions into account. Besides the advantages of S controller such as simple structure, MSC can solve the motion control of underwater vehicle at high speed which is difficult to control with S-plane controller. The stability of MSC is analyzed with Lyapunov function. Finally, MSC is applied to the motion control of an autonomous underwater vehicle controlled by rudders and thrusters. The feasibility of MSC is demonstrated by the results of velocity control, yaw control and depth control tests.

A New Control Method of Active Absorption Wave-Maker

The theory of 2D wave generation with active wave absorption is outlined. A new control method of active absorption wave-maker is established based on the S plane control (SPC) algorithm in this paper. Using SPC, a piston-type 2D numerical wave flume (NWF) simulation program for simultaneous wave generation and active wave absorption is developed with Boundary Element Method (BEM) and Mixed Eulerian-Lagrangian (MEL). The absorbing wave-making contrast simulation tests for regular wave are also carried out in NWF. Simulation results verify that the controller is robust and well effect for absorbing re-reflected wave is obtained in low reflect condition. Meanwhile, stable wave profile can be output by the absorbing wave-maker in a long time when acute reflected waves appear in the terminal of NWF.