Funnel Control Research Articles

Switched Command-Filtered-Based Adaptive Fuzzy Output-Feedback Funnel Control for Switched Nonlinear MIMO-Delayed Systems

Switched Command-Filtered-Based Adaptive Fuzzy Output-Feedback Funnel Control for Switched Nonlinear MIMO-Delayed Systems

Exact output tracking in prescribed finite time via funnel control

Output reference tracking of unknown nonlinear systems is considered. The control objective is exact tracking in predefined finite time, while in the transient phase the tracking error evolves within a prescribed boundary. To achieve this, a novel high-gain feedback controller is developed that is similar to, but extends, existing high-gain feedback controllers. Feasibility and functioning of the proposed controller is proven rigorously. Examples for the particular control objective under consideration are, for instance, linking up two train sections, or docking of spaceships.

Input-Constrained Funnel Control of Nonlinear Systems

Input-Constrained Funnel Control of Nonlinear Systems

Finite-time funnel synchronization control based on distributed observer for multi-motor driving systems with input saturation

In this article, the finite-time synchronization control problem is developed for multi-motor driving systems with input saturation. A radial basis function (RBF) neural network is utilized to estimate the unknown uncertainties and the disturbances. In contrast to current control strategies, this study proposes a new approach that utilizes a finite-time distributed observer to estimate the reference signal and then uses the estimated signal to design a synchronization controller, which effectively separates the tracking problem from the synchronous controller design. Furthermore, a funnel function is constructed to actualize the state constraints and confine the synchronization error within a specified boundary. Then, a finite-time funnel control protocol is proposed to ensure that each motor follows the estimated reference signal. Eventually, we illustrate the effectiveness of the proposed method through a numerical example.

Fixed-time disturbance observer-based funnel control for controllable excitation linear synchronous motor with state constraints

This paper proposes a fixed-time disturbance observer-based funnel control method for a controllable excitation linear synchronous motor (CELSM) with state constraints and disturbances. This approach simultaneously resolves the issues of prescribed tracking performance and state constraints, taking into account disturbances. We employ a fixed-time disturbance observer (DO) to estimate both matched and mismatched disturbances. Additionally, we design a modified funnel variable to confine the tracking error within a prescribed region and the singularity problem is avoided. An integral barrier Lyapunov function (iBLF) is utilized to directly tackle state constraints. Furthermore, we employ a fixed-time differentiator (FTD) to address the “explosion of complexity” issue in backstepping control. Theoretical analysis demonstrates that the tracking error asymptotically converges to the origin within a prescribed region while satisfying state constraints. Finally, simulation results demonstrate the efficacy of the proposed method.

Transition process-based low-complexity non-smooth funnel control for nonlinear MIMO systems

Transition process-based low-complexity non-smooth funnel control for nonlinear MIMO systems

Direct Power Regulation of Grid-Connected Voltage-Source Inverters Based on Bang-Bang Funnel Control

Direct Power Regulation of Grid-Connected Voltage-Source Inverters Based on Bang-Bang Funnel Control

Practically Predefined-Time Leader-Following Funnel Control for Nonlinear Multi-Agent Systems With Fuzzy Dead-Zone

Practically Predefined-Time Leader-Following Funnel Control for Nonlinear Multi-Agent Systems With Fuzzy Dead-Zone

Consensus Control of Multi-Agent System with Virtual Agents Considering Obstacle Avoidance

A multi-agent system (MAS) is a system whose overall behavior is determined by local interactions among multiple autonomous agents. Recently, research has been conducted on the application of MASs in real-world environments, in which the agents are assumed to be robots that drive on the ground, i.e., autonomous mobile robots, and acquire external environmental information using cameras. In such cases, the information that can be obtained by the agent is limited to the field of view (FOV) of the respective camera, and the overall graph structure is dynamic and time varying. In addition, because the FOV may be obstructed by obstacles during camera measurements, obstacle avoidance must be considered. In this study, we examined the MAS consensus problem considering the effects of a limited FOV obstructed by obstacles. Specifically, we propose a control method using virtual agents that considers obstacle avoidance based on funnel control. In addition, simulation study was performed to demonstrate the effectiveness of the proposed method for solving the MAS consensus problem in an environment with obstacles.

Correction to: Funnel control of linear systems with arbitrary relative degree under output measurement losses

Correction to: Funnel control of linear systems with arbitrary relative degree under output measurement losses

Adaptive Scaled Bipartite Consensus via Funnel Control

Adaptive Scaled Bipartite Consensus via Funnel Control

Coupled funnel control for supersonic tailless aerial vehicle on penetrating counter air

Supersonic Tailless Aerial Vehicles (STAVs) will become an essential force in Penetrating Counter Air (PCA), but STAVs do not have the traditional horizontal and vertical tails, making pitch and yaw control difficult. The attack angle and the sideslip angle need to be limited to ensure that the engine inlet and the aerodynamic rudder at the rear of the vehicle can work properly, which is the so-called security constraints. In addition, the tracking error of the aerodynamic angle needs to be limited to achieve effective attitude control or high-accuracy tracking of trajectories, which is the so-called performance constraints. To this end, an attitude control method that meets the needs of PCA has been devised, based on constraint definition, coupled constraints handling, and control law design. Firstly, mathematical descriptions of the security constraints, performance constraints, and control constraints are given. Secondly, two treatment methods, coupled command filter and coupled funnel control are proposed for the aerodynamic angle coupled constraint problem. Finally, based on Nonlinear Dynamic Inverse (NDI) design, the coupled funnel controller is designed and validated by simulation for two typical mission scenarios, high-altitude penetration and low-altitude surprise defence. The proposed control method not only satisfies the security and performance constraints of STAV attitude control but also is highly robust.

Experimental validation for the combination of funnel control with a feedforward control strategy

AbstractCurrent engineering design trends, such as lightweight machines and human–machine interaction, often lead to underactuated systems. Output trajectory tracking of such systems is a challenging control problem. Here, we use a two-design-degree of freedom control approach by combining funnel feedback control with feedforward control based on servo-constraints. We present experimental results to verify the approach and demonstrate that the addition of a feedforward controller mitigates drawbacks of the funnel controller. We also present new experimental results for the real-time implementation of a feedforward controller based on servo-constraints on a minimum phase system.

Cooperative Control for Stochastic Multiagent Systems With Deferred Dynamic Constraints via a Novel Universal Barrier Function Approach.

This article investigates the cooperative control problem for stochastic multiagent systems (MASs) with dynamic constraints. A new universal barrier function is proposed, which is applicable to many systems with different types of constraint functions, even unconstrained systems. Several mapping functions are constructed to constrain the state variables directly without feasibility conditions, and the tracking control is achieved for stochastic MASs with deferred full-state constraints under the backstepping framework. In order to regulate the tracking error more precisely, the funnel error transformation is improved and the deferred funnel controller is developed by introducing a preassigned finite-time function. Based on the deferred funnel controller, the tracking error can be maintained within the predetermined funnel in the preassigned time. The convergence time can be defined according to the actual requirements, and it is independent of the design controller parameters and initial conditions. Finally, some simulation results are given to demonstrate the effectiveness of the proposed control algorithm.

Decentralized Dynamic Event-Triggered Output Feedback Adaptive Fixed-Time Funnel Control for Interconnection Nonlinear systems.

A decentralized dynamic event-triggered output feedback adaptive fixed-time (DDETOFAFxT) funnel controller is described for a class of interconnected nonlinear systems (INSs). A novel dynamic event-triggered mechanism is designed, which includes a triggering control input, fixed threshold, decreasing function of tracking error, and a dynamic variable. To obtain the unknown states, a decentralized linear filter is designed. By introducing a prescribed funnel and using an adding a power integrator technique and a neural network method, a DDETOFAFxT funnel controller is designed to obtain better tracking performance and effectively alleviate the computational burden. Furthermore, it is ensured that the tracking error falls into a preset performance funnel. A simulation example is presented to demonstrate the availability of the designed control scheme.

Adaptive Observer-based Funnel Heading Control of Surface Vessels with Rudder Actuator Nonlinearity

In this work, an adaptive state observer based on the strictly positive real (SPR) theory in combination with funnel control is proposed for heading control of surface vessels with uncertainty in the model and subject to rudder dead-zone actuator nonlinearity. The rudder command is designed to guarantee predetermined transient and steady-state tracking performances for both heading angle and filtered virtual control tracking errors. The unknown nonlinear function in the model is tackled using an adaptive neural network and an adaptive mechanism is proposed to cope with the unknown control gain. To further improve the performance, an adaptive continuous chattering-free robust structure is considered. Using SPR Lyapunov synthesis approach, not only all the adaptive laws are derived but also it is proved that all the closed-loop signals are semi-globally uniformly ultimately bounded (SGUUB). Simulation results validate the efficiency and applicability of the proposed method.

Mixed-Gain Adaption-Based Fault-Tolerant Funnel Control of Robotic Manipulators With Unknown Dynamics and Sensor Faults

Mixed-Gain Adaption-Based Fault-Tolerant Funnel Control of Robotic Manipulators With Unknown Dynamics and Sensor Faults

Kinodynamic Motion Planning via Funnel Control for Underactuated Unmanned Surface Vehicles

Kinodynamic Motion Planning via Funnel Control for Underactuated Unmanned Surface Vehicles

Global Event-Triggered Funnel Control of Switched Nonlinear Systems via Switching Multiple Lyapunov Functions.

In this article, the global event-triggered (ET) funnel tracking control problem is studied for a class of switched nonlinear systems with structural uncertainties, where the solvability of the control problem for each subsystem is not needed. A switching multiple Lyapunov functions (MLFs) method is established, where MLFs are designed to handle switched inverse dynamics, and a switching barrier Lyapunov function is constructed to address switched sampled errors that may compromise system stability. This is achieved alongside a new switching dynamic event-triggering mechanism (DETM). By combining this method with backstepping, a dwell-time state-dependent switching law and an ET funnel controller of each subsystem are constructed, effectively eliminating the issue of the "explosion of complexity" encountered in traditional backstepping without using dynamic surface control or command filters. Additionally, the designed switching DETM ensures that the tracking error always evolves within a performance funnel in any consecutive triggering interval, excluding Zeno behavior, and guaranteeing positive constant lower bounds for two consecutive triggering intervals and any switching interval, respectively. Finally, an example is provided to show the validity of the theoretical results.

Posture Adjustment for a Wheel-Legged Robotic System Via Leg Force Control With Prescribed Transient Performance

This work proposes a force control strategy with prescribed transient performance for the legs of a wheel-legged robotic system to realize the posture adjustment on uneven roads. A dynamic model of the robotic system is established with the body posture references and feedback to calculate the desired leg forces, which are the tracking references for the wheel-legs. Based on the funnel control scheme, the legs realize force tracking with prescribed transient performance. To improve the robustness of the force control system, an event-triggering condition is designed for the online segment of the funnel function. As a result, the force tracking error of the wheel-leg evolves inside the performance funnel with proven convergence. The absence of Zeno behavior for the event-based mechanism is also guaranteed. The proposed control scheme is applied to the wheel-legged physical prototype for the performance of force tracking and posture adjustment. Multiple comparative experimental results are presented to validate the stability and effectiveness of the proposed methodology.