Active Compensation Control Research Articles

Multi-step prediction of ship heave motion using transformer-enhanced multi-scale CNN

To achieve precise multi-step heave motion prediction for active compensation control in marine equipment, an innovative approach that integrates an attention-fused multi-scale CNN with a Transformer encoder is introduced in this study. The dual-path CNN and point-wise convolution-enhanced Transformer encoder are designed to capture local features across various scales and the global characteristics of heave motion signals, respectively. Furthermore, a novel optimization objective which combines a slope factor-optimized Huber loss function with a maximum square distance loss function is proposed to better approximate the original signals at extreme points. The proposed model is trained and tested on simulated data under multiple sea conditions. In typical active compensation scenarios (Hs=3.5m), the proposed model demonstrates superior performance compared to baseline methods, achieving an RMSE of 0.0083 m, an MAE of 0.0066 m, and the upper whisker of the box plot for the prediction error is less than 0.02 m. These outcomes effectively satisfy the accuracy requirements for active compensation systems. The generalization test on real-ship collected data demonstrates excellent performance after fine-tuning. Additionally, the model is considered suitable for deployment in real-world applications due to its memory efficiency and fast inference speed.

Event-triggered lifted robust MPC stabilization control for space telescope on dual-rate actuated rigid spacecraft systems

This study addresses the pose stabilization control problem for enhancing a space telescope mounted on a spacecraft system under a dual-rate actuated setup. An input-lifting approach is utilized to manage the dual rates in the control components, specifically the orbital space telescope and its loading platform. To counteract external spatial perturbations and spacecraft system uncertainties, an integrated control scheme is proposed, combining real-time model parameter estimation, active compensation control, and event-triggered lifted robust model predictive control (ET-LRMPC). The event-triggered mechanism in the proposed algorithm minimizes computational resource consumption while maintaining effective spacecraft control. Numerical simulations demonstrate that the proposed control scheme achieves favorable results under persistent external perturbations and model uncertainties. In terms of the overshoot, the algorithm proposed reduces the control effect by up to 87.1% in the spatial displacement of the payload and 98.6% in the Euler attitude angle compared to the conventional control algorithm. For the control of the base, the amount of overshoots with respect to the conventional control in spatial displacement and Euler attitude angle is reduced by 49% and 97.1%.

Robust fault-tolerant control for four-wheel individually actuated electric vehicle considering driver steering characteristics

A robust fault-tolerant control scheme for distributed actuated electric vehicles is proposed to maintain vehicle stability suffering actuator faults while considering the driver personality differences. The proposed scheme integrates the cooperative game and terminal sliding mode control into the framework of the feedback linearization method (FLM). Firstly, the nonlinearities of the driver-vehicle system are treated by the knowledge of Lie derivative, and then a set of controllable virtual subsystems is obtained through diffeomorphism. To achieve multi-objective cooperation, the interaction framework of virtual subsystems is modeled based on cooperative game theory, which provides a basic feedback control scheme (BFCS). Finally, a terminal sliding mode technology-based active compensation control scheme is integrated into BFCS to handle the systemic disturbances caused by actuator faults. An implementation of hardware-in-the-loop verifies that the stability of the vehicle under the control of the developed approach can be guaranteed for different drivers and different fault types.

Enhanced Modeling and Control for Multilinked Aerial Robot With Two DoF Force Vectoring Apparatus

The multilinked or modular structure is one of the state-of-the-art topics in aerial robot field. One type of the multilinked aerial robot called DRAGON containing a two degree-of-freedom (DoF) force vectoring apparatus in each link has been developed in our previous work to augment both maneuvering and manipulation ability. However, several types of invalid robot poses, which are due to the mechanical structure, the previous control method and the interrotor aerodynamic interference, significantly reduce the region of deformation. Thus, enhanced modeling and control methods are necessary to overcome these problems. In this letter, we first develop an integrated thrust and vectoring control method with a rigorous allocation to solve the control singularity. Second, we present a vectoring configuration planning method, which solves the mechanical singularity by locking one of the axes in the two DoF vectoring apparatus. Finally, we propose an estimation method and an active compensation control regarding the aerodynamic interference to improve the flight stability. In the end, simulation studies and experiments involving the hovering and deformation along a vertical plane are performed to evaluate the whole modeling and control framework.

Dynamic Coordination Control of HEV Unsteady Operating Mode Switching Based on MPC

Aiming at a hybrid electric vehicle (HEV), the impact problem is studied during the mode switching process under non-steady-state operating conditions. Firstly, the system dynamics model is established, the dynamic characteristics of unsteady conditions are analyzed, the BP neural network engine torque estimation model based on genetic algorithm optimization is established, and the engine torque is estimated online. MG1 torque coordination control and MG2 active compensation control are adopted, a mode switching coordination control strategy based on model prediction is proposed. The MATLAB / Simulink simulation platform is used to verify the effectiveness of the control algorithm. The simulation results show that the coordinated control strategy can effectively achieve the output torque compensation of the drive motor. The engine is actually close to the target torque. Compared with the uncoordinated control, During the speed synchronization phase, the maximum impact of the vehicle was reduced by 60.4%.

Multivariate orthogonal polynomial-based positioning error modeling and active compensation of dual-driven feed system

The nonsynchronous error of the dual-driven feed system seriously affects the positioning and machining accuracy of CNC machine tools. Improving the positioning error is an extremely important task as it determines the geometric accuracy of the manufactured parts. In this paper, a Multivariate Orthogonal Polynomial Regression model has been developed to predict the positioning error in terms of motion parameters such as position and speed of the X1 and X2 axes of the dual-driven worktable. Orthogonal Experimental Design has been engaged in conducting experiments. The positioning errors are measured by a dual-frequency laser interferometer. In addition, a real-time error compensation system is developed based on the proposed active compensation control strategy in the dual-driven feed system controlled by Beckhoff motion control card. Experimental results show that the proposed positioning error model and error compensation strategy can be utilized as an effective manner to improve the accuracy of dual-driven CNC machine tools.

Simulation and experiment of a turbine access system with three-axial active motion compensation

This study aims to investigate a new turbine access system (TAS) for offshore wind farms in Taiwan Strait sea conditions having a wave period of 7.5 s and a significant wave height of 1.5 m, including the novel system integration of mechanism design, hydraulic driving system, and control system. The dynamic co-simulation of TAS is achieved firstly for confirming the system design and parameters. After that, a full-scale test rig is set up for experimental verification. The vertical height, the roll angle and the vertical acceleration of the TAS end effector can be reduced effectively through the active motion compensation control for improving the access safety of the offshore wind turbine.In simulation, the dynamic modelling of mechanism is implemented by software ADAMS. The hydraulic driving system and the control system are derived mathematically in this study and implemented via MATLAB/SIMULINK. Then, the dynamic simulation of TAS is achieved through the co-simulation of ADAMS and MATLAB/SIMULINK for verifying the active compensation control performance of TAS. In addition, fuzzy sliding mode control is used to develop the roll and pitch controllers for improving the compensation performance.In the experiment, a full-scale test rig of TAS is set up for verifying the effect of active compensation control system experimentally. Through the active compensation control experiment in the full-scale test rig, the vertical height, the rolling angle and the vertical acceleration of the TAS end effector can be reduced and validated by practical experiments.

Active control of friction-induced self-excited vibration using adaptive fuzzy systems

Vibration caused by friction is harmful to engineering systems. Understanding the mechanism of such a physical phenomenon and developing some strategies to effectively control the vibration have both theoretical and practical significance. Based on our previous work, this paper deals with a problem of active compensation control of friction-induced self-excited vibration using adaptive fuzzy systems. Comparative studies on control performance are carried out, where a class of adaptive compensation control schemes with various friction models are applied to control a motion dynamics with friction. It is observed that our proposed modeling and control techniques are powerful to eliminate the limit cycle and the steady-state error. Furthermore, robustness of the proposed controller with respect to external disturbances is discussed. Simulation results show that the active controller with adaptive fuzzy friction compensation outperforms other active controllers with compensation terms characterized by three well-known friction models.