Coupling Control Strategy Research Articles

Nonlinear Vibration of Manipulator Induced by Coupling Time Delay and Control Strategy

This article uses the theory of Hopf bifurcation to study the stability[1-2] of nonlinear manipulator system with time delay built by Spong. The period vibration, almost periodic vibration and chaos motion are stabilized by the controllers designed in the article, which is achieved by changed the polynomial u in the dynamic of manipulator. It is proved that the controllers in this article are useful by calculating the eigenvalues of the linear form of the dynamic of manipulator, which are expressed in the complex plane, according to the stability theory[2].

A Thermoelectric Coupling Control Strategy Based on FDP for REEVs Under Low-temperature Environment

Abstract Efficient energy management strategy (EMS) and thermal management strategy (TMS) are important to improve the energy efficiency of the range extender electric vehicles (REEVs). This paper aims to develop a thermaoelectric coupling control strategy for REEVs in low-temperature environment with the comprehensive consideration of the coupling relationship between energy management system and thermal management system of REEVs. First, a coupled thermal management system (CTMS) is designed in order to efficiently use the engine waste heat to preheat the power battery in low-temperature. Sequentially, a forward dynamic programming (FDP) method is employed to solve the optimal problem considering the impact of the thermal system dynamics on energy consumption. Finally, simulation results show that the proposed strategy efficiently reduces the warm-up time of the battery and improves the energy utilization efficiency.

Coupled Bending Inwards Motion and Control Strategy Analysis of a Cable-Driven Underactuated Finger

Motion strategy analysis at the pre-bending stage is a fundamental component of underactuated finger grasp research. This study presents the pre-bending motion strategy and corresponding analysis of cable driving forces a 3-DOF underactuated finger comprising cable truss units. The structure and four motion strategies at the pre-bending stage are illustrated. The equivalent joint-driven and quasi-static motion models are established in the case where one or two cable driving forces drive the finger. Quasi-static motion model is established, and four typical quasi-static coupled motion space and distributions of corresponding cable driving forces are analysed. In accordance with the kinetic energy theorem and Lagrange’s dynamical method, a sampled and general dynamic model is established. Through matrix transformation, a hypothetical “PPA” type dynamic model is obtained. On the basis of the “PPA” dynamic model, three grasping control strategies at pre-bending stage are carried out. Valid simulations and experiments are conducted to verify the accuracy of the coupled bend inwards motion and control strategy.

Optimal control and cost-effectiveness analysis of a Huanglongbing model with comprehensive interventions

Huanglongbing (HLB) is currently one of the most devastating citrus plant diseases. To better understand the spread of HLB disease, the stage-structured compartmental model is formulated to describe the transmission dynamics of HLB between the citrus trees and Asian citrus psyllid (ACP). Based on strict mathematical derivations, the explicit expression for the basic reproduction number (R0) of HLB is derived. The dynamics of the model are rigorously analyzed by using the theory of dynamical system. The theoretical results show that the disease-free equilibrium is globally asymptotically stable if R0<1, and if R0>1 the system is uniformly persistent. By applying the global sensitivity analysis of R0, we can obtain some parameters with the most significant influence on the transmission dynamics of HLB. Moreover, the optimal control theory is used to investigate the corresponding optimal control problem of the epidemic model. Numerical simulations are conducted to reinforce the analytical results. Using the cost-effectiveness analysis, the superiority of various intervention strategies is compared by calculating Incremental Cost-Effectiveness Ratio (ICER) value. The findings imply that coupled control strategy involving insecticide spraying treatment and HLB-symptomatic trees removal is the most cost-effective strategy and belongs to long-term intervention measures, and it is recommended to take this strategy to control the disease in the whole process. On the contrary, nutrient solution treatment and yellow sticky trap control are short-term intervention measures, which can be used at the initial stage of disease outbreak but discontinued at the later stage due to cost considerations. These findings provide us potential decision-making tools that allow managers to choose better control strategies of HLB.

Multimotor Improved Relative Coupling Cooperative Control Based on Sliding-Mode Controller

To provide cooperative control under complex working conditions of a filling multimotor system, this paper proposes a relative coupling control strategy with a switching system structure. Firstly, a multistation transmission system composed of a filling motor and a transfer motor is designed according to different filling processes. Secondly, a stable sliding-mode surface common to the multimotor system is selected, and an equivalent sliding-mode controller corresponding to each motor is designed. Thirdly, public Lyapunov stability theory is used to prove that the switched system can move from any initial state to the common sliding surface of the system, thereby ensuring the asymptotic stability of the entire system. Simulation results show that this method has a more significant control effect on the system error of each motor in comparison with the traditional relative coupling control structure.

Topological manifold‐based monitoring method for train‐centric virtual coupling control systems

Train-centric virtual coupling is one of the promising techniques available to increase the capacity of the railway, and is much more complex than the existing train control systems. The safety issue for the system needs to be addressed since virtually coupled trains are allowed to run closer than under the traditional fixed/moving block principle. In this study, the authors proposed a topological manifold-based monitoring method to guarantee the safety of the train-centric virtual coupling systems. The basic signalling equipment and dynamic train behaviour are described as topological elements and manifolds. Based on that, several safety monitoring theorems are proved to ensure the safety of the virtual coupling control logic. The theorem for the verification of trains running information is proved, along with theorems for the correctness of the virtual coupling control strategy. The trains' dynamic behaviour under specific control commands can also be supervised by a safety theorem. Finally, a case study is performed to illustrate the proposed method. The results show that the method is feasible for monitoring the train-centric virtual coupling control systems.

Coupling Control Strategy and Experiments for Motion Mode Switching of a Novel Electric Chassis

A flexible chassis (FC) is a type of electric vehicle driven by in-wheel motors that can be used in narrow conditions in agricultural facilities. The FC is composed primarily of four off-center steering mechanisms (OSMs) that can be controlled independently. Various FC operation modes can be achieved including cross motion (CM), in-place rotation (IR), diagonal motion (DM), and steering motion (SM). However, it is difficult to achieve satisfactory motion mode switching (MMS) results under traditional distribution control methodologies due to a lack of linkage relationships between the four OSMs. The goal of this study was to provide a coupling control method that can cope with this problem. First, dynamic MMS models were derived. Then, an MMS coupling error (CE) model was derived based on coupling control and Lyapunov stability theory. Second, a fuzzy proportional integral derivative (PID) controller with self-tuning parameters was designed to reduce the CE during MMS. A fuzzy PI controller was also employed to improve response times and decrease OSM tracking motion steady-state error. Finally, MATLAB/Simulink simulations were performed and experimentally validated on hard pavement. The results showed that the proposed methodology could effectively reduce CE and guarantee MMS control stability while substantially shortening response times. The proposed methodology is effective and feasible for FC MMS.

A Cross Coupling Control Strategy for Dual-Motor Speed Synchronous System Based on Second Order Global Fast Terminal Sliding Mode Control

A cross coupling control strategy based on second-order global fast terminal sliding mode control(2-GFTSMC) is proposed in this paper aiming to improve the synchronization accuracy of dual-motor under external load and disturbance. Firstly, the global fast terminal sliding mode controller is designed to improve the starting performance and dynamic performance of single motor and eliminate chattering phenomenon. Secondly, in order to improve the synchronization accuracy, enhance the stability of the dual-motor system and shorten the response time, a second-order global fast terminal sliding mode controller is designed by combining the global fast terminal sliding mode control with the cross-coupling control strategy. Finally, an experimental platform of dual-motor synchronous control is built, and the effectiveness of the proposed synchronization control strategy is verified by experiments.

Multiaxis Servo Synergic Control Based on Sliding Mode Controller

This paper investigates a relative coupling control strategy based on the sliding mode controller to solve the problem of poor synergy performance of the axes of the dynamic seat during operation and to realize the multiaxis servo synergic control with variable proportions during the operation of the system. Firstly, the proposed method is theoretically proven to be accurate in eliminating tracking errors and synchronization errors between servos in the process of system operation. Secondly, the system simulation model is built in the Simulink simulation environment of MATLAB. On one hand, the final simulation result verifies the accuracy of the theoretical proof. On the other hand, the control strategy is characterized by fast convergence, high synchronization accuracy, and strong robustness; thus, the system has excellent synergy performance. Finally, the motion control platform of the dynamic seat was built for physical verification. The experimental result shows the effectiveness and feasibility of the control strategy.

Cascade Optimal Control for Tracking and Synchronization of a Multimotor Driving System

This brief investigates the optimal control design for a multimotor driving system (MDS). Since the dynamic characteristic of MDS is multivariable, high order, strong coupling, and nonlinear, it is difficult to design an appropriate control framework to simultaneously achieve the load tracking and multimotor synchronization. By dividing the MDS into a load subsystem and a multimotor subsystem, a novel cascade optimal control framework including outer and inner loops is proposed. In this framework, the optimal-tracking controller (OTC) and the optimal synchronization controller (OSC) can be designed individually by decomposing a comprehensive performance index. In order to construct the OTC, the backstepping approach is incorporated into the optimal control to make the load track a reference command; then, the OSC is developed via the mean deviation coupling control strategy to guarantee that all the motors’ states can converge their average value. In addition, the state and extended disturbance observers are combined with OTC and OSC to deal with the immeasurable states and the system uncertainties. The proposed control framework not only addresses the optimal control problems of the load tracking and multimotor synchronization but also has a strong robustness to the system uncertainties. The Lyapunov theory proves that all signals in the closed-loop system are ultimately uniformly bounded. Practical experiments based on a four-motor driving system are conducted to validate the efficiency of the proposed control framework.

Coupling Control Strategy of Force and Displacement for Electric Differential Power Steering System of Electric Vehicle With Motorized Wheels

This paper presents a coupling control strategy of force and displacement for an electric differential power steering (EDPS) system to improve steering maneuverability and handling stability of electric vehicles with motorized wheels. In order to investigate mutual influences between vehicles and drivers, models of the EDPS system, the vehicle, the tire as well as the actuate motor are introduced. Then, by analyzing key factors that affect the interaction between vehicles and drivers, the optimum hand wheel torque of the EDPS system is developed and actualized by torque difference between two front wheels based on the ${\text{H}}_{2}{\text{/ H}}_{{{\infty }}}$ control method. In addition, a yaw rate control method is schemed to diminish the yaw moment interference to vehicles caused by the torque difference between two front wheels, and μ-synthesis theory is applied here to improve the yaw rate tracking performance as well as attenuate influences of system uncertainties and disturbances. Finally, simulations by MATLAB/Simulink and hardware-in-the-loop experiments based on dSPACE are conducted and effectiveness of the proposed control strategy is demonstrated by simulation and experiment results and numerical analyses.

Robust tracking and distributed synchronization control of a multi-motor servomechanism with H-infinity performance

The multi-motor servomechanism (MMS) is a multi-variable, high coupling and nonlinear system, which makes the controller design challenging. In this paper, an adaptive robust H-infinity control scheme is proposed to achieve both the load tracking and multi-motor synchronization of MMS. This control scheme consists of two parts: a robust tracking controller and a distributed synchronization controller. The robust tracking controller is constructed by incorporating a neural network (NN) K-filter observer into the dynamic surface control, while the distributed synchronization controller is designed by combining the mean deviation coupling control strategy with the distributed technique. The proposed control scheme has several merits: 1) by using the mean deviation coupling synchronization control strategy, the tracking controller and the synchronization controller can be designed individually without any coupling problem; 2) the immeasurable states and unknown nonlinearities are handled by a NN K-filter observer, where the number of NN weights is largely reduced by using the minimal learning parameter technique; 3) the H-infinity performances of tracking error and synchronization error are guaranteed by introducing a robust term into the tracking controller and the synchronization controller, respectively. The stabilities of the tracking and synchronization control systems are analyzed by the Lyapunov theory. Simulation and experimental results based on a four-motor servomechanism are conducted to demonstrate the effectiveness of the proposed method.

Multi-channel synchronization control based on mean of deviation coupling control

The development status of multi-channel synchronous control strategy is analyzed, and a new mean of deviation coupling control strategy based on the thought of the same given control and error compensation is presented, which can reduce complexity of the control structure with the increasing number of channels. The mathematical models of PMSM (Permanent Magnet Synchronous Motor) and load are established. The global stability and convergence of the control system have been proved according to Lyapunov stability theory. In this paper, mean of deviation coupling control strategy is applied to the synchronization control system of multi-channel, and compared with master-slave control strategy. The simulation results not only show the effectiveness of the proposed control approach, but also verify that the proposed control strategy is better than master-slave control strategy, which has better anti-interference and synchronous control performance.

Analysis of RLV’s Coupling Characteristic and Control Strategy Design

Reusable launch vehicle (RLV) in the reentry process exhibit fast time-variation, strongly nonlinear and cou- pling characteristics, they all increase the complexity of attitude control system. After a vehicle's mathematical model is built for the analysis of RLV movement and attitude control system design, then some operating points are selected from the trajectory and linearized. Several common coupling mechanisms are described, including the inertial coupling, the motion coupling, the Dutch coupling and the control coupling. Calculation results of rapid roll stability boundary are giv- en, and a criterion of the Dutch-roll motion stabilization is proposed. Based on the analysis of the coupling characteristics, a RLV longitudinal and lateral/directional motion control strategy is designed: elevators are used to trim and control on the longitudinal channel; body flaps and RCS are used to hybrid control on the lateral/direction channel at low dynamic pressure and at high dynamic pressure body flaps can work alone. Finally, the 6 DOF simulation results prove the validity of the control strategy.

Study on the Ratio Control of Metal Belt CVT Based on the Hardware in the Loop Simulation

The study investigates the structure and characteristic of Continuously Variable Transmission (CVT) through building the hardware-in-the-loop test bed of the CVT. Matlab/Simulink is utilized to establish a vehicle simulation model and a speed ratio and clamping force coordinated control model. In addition, the speed ratio test, based on the active coupling control strategy, is carried out with the result of contrast curves between coupling control and traditional speed ratio control strategy. The real-time simulation proves a better controlling effect.

Design and Coupling Control Strategy for Parallel Hybrid Excavator

Design and Coupling Control Strategy for Parallel Hybrid Excavator

Modeling and Simulation of Hydraulic Roll Bending System Based on CMAC Neural Network and PID Coupling Control Strategy

The hydraulic roll bending control system usually has the dynamic characteristics of nonlinearity, slow time-variance and strong outside interference in the rolling process, so it is difficult to establish a precise mathematical model for control. So, a new method for establishing a hydraulic roll bending control system is put forward by cerebellar model articulation controller (CMAC) neural network and proportional-integral-derivative (PID) coupling control strategy. The non-linear relationship between input and output can be achieved by the concept mapping and the actual mapping of CMAC. The simulation results show that, compared with the conventional PID control algorithm, the parallel control algorithm can overcome the influence of parameter change of roll bending system on the control performance, thus improve the anti-jamming capability of the system greatly, reduce the dependence of control performance on the accuracy of the analytical model, enhance the tracking performance of hydraulic roll bending loop for the hydraulic and roll bending force and increase system response speed. The results indicate that the CMAC-PID coupling control strategy for hydraulic roll bending system is effective.

Research on Overrunning-clutch Speed Coupling Control Strategy in a Parallel Plug-in Hybrid Electric Vehicle

To resolve issues of powertrain components’ speed coupling based on overrunning-clutch which is applied to the Parallel Plug-in Hybrid Electric Vehicle (PHEV), the speed coupling control strategy of a PHEV is put forward. The controller models are established by using Matlab/Simulink according to the structure of overrunning-clutch, and the discrete PID controllers accurately control powertrain components’ output speed. The real-time simulation is performed on dSPACE platform. Experimental results indicate that powertrain components’ output speed are coupled accurately and the power are distributed, which achieve the smooth power switching requirements and satisfy load capacity.

ACTIVE CONTROL OF FORCED AND UNFORCED STRUCTURAL VIBRATION

An analytical approach to vibration control is presented, and verified experimentally, for cases where it is undesirable to add actuators with significant mass and stiffness to the structure. A linear coupling control (LCC) strategy is implemented by coupling a second order linear system to an oscillatory plant to create an energy exchange between the two component systems. One of the advantages of this approach is that the control strategy is ultimately capable of controlling unforced and periodically forced vibrations in the plant.The paper covers the application of the LCC control strategy to a cantilevered beam actuated by piezoceramic actuators. A novel model for the piezoactuated beam is derived for any representative mode, resulting in a set of linearized equations. Also, the model provides flexibility in actuator location and dimensions.The controller is modelled as a single-degree-of-freedom linear oscillator which is coupled to the plant via linear terms. The result is a small actuating force, or weak coupling between plant and controller which lends itself well to piezoceramic actuation. This system is solved as a linear eigenvalue problem which provides a computationally efficient means of finding the response.The solution is also verified by means of a finite element (FE) simulation which is carried out for both free and forced vibration. Apart from confirming the theoretical model and closed-form solution, the FE method provides another flexible means in predicting the response of the LCC strategy, the control strategy and the theoretical studies have been verified experimentally.

An Investigation Into the Compliance of SCARA Robots. Part II: Experimental and Numerical Validation

A model of inherent elastic compliance was developed for general position-controlled SCARA, with conventional joint feedback control, for both rotational and prismatic part insertion (Part I). The developed model was applied to the SKILAM and ADEPT I robots for validation. Experimental procedures and numerical solution methods are described. It was found that the ADEPT I robot employs a coupled control strategy between joints one and two which produces a constant, decoupled end effector compliance. The applicable compliance matrix, in this case, is presented and the experimental results are discussed. The model may be used to develop compliance maps that define the amount of end effector compliance, as a function of the joints compliance, as well as its variation for different robot configurations. This is illustrated using data for the SKILAM SCARA robot. Results are plotted and discussed. The most appropriate robot postures for assembly were found for both rotational and prismatic parts. The conditions necessary to achieve compliance or semicompliance centers with the SKILAM robot were examined. The results and methods demonstrated in these examples may be used to select appropriate robots for given applications. They can also guide robot designers in selecting joint servo-control gains to obtain the desired joints compliance ratio and improve assembly performance.