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This paper considers a problem of tracking control design for different types of nonholonomic mobile manipulators. The mobile platform is in form of a unicycle. In the first step, an input–output decoupling controller is developed. The proposed selection of output functions is in more general form than the output functions previously introduced by others [Yamamoto and Yun]. It makes possible to move simultaneously, the mobile platform and the manipulator built on it. Regularity conditions that guarantee the existence of the input–output decoupling control law are presented. In the second step, trajectory and path tracking controllers are formulated and presented. Theoretical considerations are illustrated with simulations for the mobile manipulator consisting of a vertical, three degree of freeedom (DOF) pendulum (with holonomic or nonholonomic drives) mounted atop of a unicycle.

The most distinctive difference between a space robot and a base-fixed robot is its free-flying/floating base, which results in the dynamic coupling effect. The mounted manipulator motion will disturb the position and attitude of the base, thereby deteriorating the operational accuracy of the end effector. This paper focuses on decoupling or counteracting the coupling between the manipulator and the base. The dynamics model of multi-arm space robots is established using the composite rigid dynamics modeling approach to analyze the dynamic coupling force/torque. An adaptive robust controller that is based on time-delay estimation (TDE) and sliding mode control (SMC) is designed to decouple the multi-arm space robot. In contrast to the online computation method, the proposed controller compensates for the dynamic coupling via the TDE technique and the SMC can complement and reinforce the robustness of the TDE. The global asymptotic stability of the proposed decoupling controller is mathematically proven. Several contrastive simulation studies on a dual-arm space robot system are conducted to evaluate the performance of the TDE-based SMC controller. The results of qualitative and quantitative analysis illustrate that the proposed controller is simpler and yet more effective.

In this paper, we analyze automotive chassis system modeling and subsystem control to construct a nonlinear chassis system by analyzing the dynamics of the whole vehicle, handling process, and manufacturing process. Secondly, the integrated braking system decoupling controller is designed to control both friction and electromagnetic integrated brake systems effectively. Finally, the Simulink simulation model is integrated into Matlab software to conduct an imitation study of the control system. When the brake controller is activated, the findings show that the wheel’s slip rate drops to almost 0.2, which is close to the desired value. The vehicle’s braking distance with conventional braking is close to 40m, but it is reduced to about 30m under the action of the ABS system, which effectively shortens the braking distance and ensures the vehicle’s safety in braking.

Plant factory is an important field of practice in smart agriculture which uses highly sophisticated equipment for precision regulation of the environment to ensure crop growth and development efficiently. Environmental factors, such as temperature and humidity, significantly impact crop production in a plant factory. Given the inherent complexities of dynamic models associated with plant factory environments, including strong coupling, strong nonlinearity and multi-disturbances, a nonlinear adaptive decoupling control approach utilizing a high-order neural network is proposed which consists of a linear decoupling controller, a nonlinear decoupling controller and a switching function. In this paper, the parameters of the controller depend on the generalized minimum variance control rate, and an adaptive algorithm is presented to deal with uncertainties in the system. In addition, a high-order neural network is utilized to estimate the unmolded nonlinear terms, consequently mitigating the impact of nonlinearity on the system. The simulation results show that the mean error and standard error of the traditional controller for temperature control are 0.3615 and 0.8425, respectively. In contrast, the proposed control strategy has made significant improvements in both indicators, with results of 0.1655 and 0.6665, respectively. For humidity control, the mean error and standard error of the traditional controller are 0.1475 and 0.441, respectively. In comparison, the proposed control strategy has greatly improved on both indicators, with results of 0.0221 and 0.1541, respectively. The above results indicate that even under complex conditions, the proposed control strategy is capable of enabling the system to quickly track set values and enhance control performance. Overall, precise temperature and humidity control in plant factories and smart agriculture can enhance production efficiency, product quality and resource utilization.

Dynamometers are used to evaluate the real-world performances of drivetrains in various loading conditions. Due to its superior power density, high bandwidth, and design flexibility, a hydrostatic power-regenerative dynamometer is an ideal candidate for hydrostatic wind turbine transmission testing. A dynamometer can emulate the wind turbine rotor dynamics and allow the investigation of the performance of a unique hydrostatic drivetrain without actually building the physical system. The proposed dynamometer is an energy-efficient system with counter-intuitive control challenges. This paper presents the dynamics, control synthesis, and experimental validation of a power-regenerative hydrostatic dynamometer. A fourth-order non-linear model with three inputs was formulated for the dynamometer. The strength of input–output couplings was identified, and two different decoupling controllers were designed and implemented. During wind turbine testing, the synchronous generator turns at a constant speed and the system model is linear. A steady-state decoupling controller was developed for independent control of the drive and transmission. The implemented decoupling controller demonstrated a negligible change in rotor speed for a 40 bar step increase in pressure, but a 20 bar pressure spike for a 4 rpm step change in rotor speed. However, during starting and stopping, the synchronous generator speed is not constant, and the system model is nonlinear. Therefore, a steady-state decoupling controller will not work. Thus, a decentralized controller with feed-forward control and gain scheduling was designed and implemented. A reference command was designed to avoid cavitation, pressure spikes, and power flow reversal during start-up. The experimental results show precise tracking in steady-state and transient operations. The decentralized controller demonstrated a negligible change in rotor speed for a 40 bar step increase in pressure but a 100 bar pressure spike for a 4 rpm step increase in rotor speed. The pressure spike was reduced by 80 bar with the implementation of feed-forward gain. The proposed electro-hydro-mechanical system requires less power and has the potential to reduce energy expenditure by 50%.

The Magnetic Suspension Balance System (MSBS) serves as a core apparatus for interference-free aerodynamic testing in wind tunnels, where its high-precision levitation control performance directly determines the reliability of aerodynamic force measurements. This paper addresses the strong coupling issues induced by rigid-body motion in the MSBS vertical suspension system and proposes a decoupling control framework integrating classical decoupling methods with geometric feature transformation. First, a nonlinear dynamic model of the six-degree-of-freedom MSBS is established. Through linearization analysis of the vertical suspension system, the intrinsic mechanism of displacement-pitch coupling is revealed. Building upon this foundation, a state feedback decoupling controller is designed to achieve decoupling among dynamic channels. Simulation results demonstrate favorable control performance under ideal linear conditions. To further overcome its dependency on model parameters, a decoupling strategy based on geometric feature transformation is proposed, which significantly enhances system robustness in nonlinear operating conditions through state-space reconstruction. Finally, the effectiveness of the proposed method in vertical suspension control is validated through both numerical simulations and a physical MSBS experimental platform.

Magnetic liquid double suspension bearing (MLDSB) is composed of an electromagnetic system and hydrostatic system and its bearing capacity and stiffness can be greatly improved. It is very suitable for occasions of medium speed, heavy load, and starting frequently. Due to the gyroscopic effect and interference between the supporting system, the space state of the rotor can be affected and the operation stability of the MLDSB can be reduced greatly. Therefore, the coupling features of the multi-degree of freedom (multi-DOF) system are analyzed and a decoupling controller is designed and verified in the paper. Firstly, the paper introduces the structural characteristics, stress forms, and control regulation mechanism. Then, the mathematical transfer function of the multi-DOF supporting system is established and the coupling principle is revealed. The state feedback decoupling controller is designed by means of a state feedback decoupling, and its decoupling effect is analyzed by the Simulink module. Finally, the single-DOF decoupling system is independently controlled by the use of the root locus method. The coupling characteristics between channel x and channel y are tested experimentally, and the decoupling controller is added and its effect tested. The results show that the state feedback decoupling controller can effectively reduce the coupling degree in the multi-DOF system and convert the multi-DOF coupling problem into a single-DOF independent control problem. The coupling effect of channel x and channel y is reduced by using the decoupling controller, with the subsequent displacement characteristic of the rotor increased, and then the operation stability of the MLDSB is improved greatly. This paper can enrich the support system of the MLDSB and provide a theoretical reference for stability control.

In the d-q coordinate system, UPFC mathematical model reveals a nonlinear system with features of a multi-variable, strong coupling, and more interference. In view of these system characteristics, the paper presents a nonlinear overlapping decoupled strategy with better stability and dynamic performance for UPFC control. The control strategy is analyzed and tested with the MATLAB simulative experiments. Simulation results show that the proposed control strategy can quickly and accurately respond to the needs of the power system, and realize real power and reactive power decoupling control effectively. Keywords: Dynamic Modeling, Nonlinear, Decoupling Controller, UPFC, MATLAB

A practical iterative tuning algorithm of a decoupling controller is presented to eliminate intrinsic coupling among 3-DOF precision motion stage. General decoupling control cannot eliminate coupling completely, which will prevent the enhancement of control accuracy in high-precision motion system. The proposed algorithm can be used to tune the parameters of a decoupling controller iteratively through minimizing a quadratic cost function of the tracking error in non-movement direction when the stage moves in one direction. The tuning algorithm addressed for the motion stage needs only measurement signals in an actual motion system rather than a detailed model of the stage. The proposed algorithm is demonstrated by experimental results. It can be applied further in other multi-DOF motion systems.

We obtain an optimal H 2 decoupling controller for rectangular plants in a standard two-degree-of-freedom controller configuration model. The class of all stabilizing and decoupling loop controllers is parameterized in terms of free diagonal parameter matrices. We determined the optimal decoupling controller from these free parameters. Inner-outer factorization and the Khatri-Rao product expression for the vector operation to a diagonal matrix are the key steps in obtaining the H 2 optimal solution. We provide a compact set of assumptions to assure the existence of the optimal solution.