Finite-time Trajectory Research Articles

Finite-time trajectory tracking control of quadrotor UAVs based on neural network disturbance observer and command filter

Finite-time trajectory tracking control of quadrotor UAVs based on neural network disturbance observer and command filter

Prescribed finite-time tracking control with input buffer for a manipulator system

The prescribed finite-time trajectory tracking control problem with input buffer is investigated for a linkage manipulator system. The backstepping method is used to design the prescribed finite-time trajectory tracking controller. A new prescribed finite-time performance function is proposed, which can more easily regulate control performance. With the help of this performance function, a constraint control law is designed for the tracking error, and a better transient performance than the existing prescribed finite-time performance function can be obtained under the same parameter conditions for the trajectory tracking process of the manipulator system. At the same time, a control input buffer function is designed, which solves both the overvoltage problem of control input caused by the overlarge position error of the manipulator and the problem that the manipulator system is difficult to start under heavy load. The simulation experiments verify the effectiveness and superiority of the proposed controller.

Tuning Transduction from Hidden Observables to Optimize Information Harvesting.

Biological and living organisms sense and process information from their surroundings, typically having access only to a subset of external observables for a limited amount of time. In this Letter, we uncover how biological systems can exploit these accessible degrees of freedom to transduce information from the inaccessible ones with a limited energy budget. We find that optimal transduction strategies may boost information harvesting over the ideal case in which all degrees of freedom are known, even when only finite-time trajectories are observed, at the price of higher dissipation. We apply our results to red blood cells, inferring the implemented transduction strategy from membrane flickering data and shedding light on the connection between mechanical stress and transduction efficiency. Our framework offers novel insights into the adaptive strategies of biological systems under nonequilibrium conditions.

Extended state observer-based finite-time trajectory tracking control for wheeled mobile robots under FDI attacks

The trajectory tracking control of wheeled mobile robots (WMRs) under False Data Injection (FDI) attacks is investigated in this paper. First, to mitigate the impact of FDI attacks, a finite-time extended state observer (FTESO) is constructed. The error dynamic of the tracking control system is then split up into two subsystems via the cascaded control approach, and a one-to-one finite-time control law is designed for both subsystems. Second, a new stability condition is proposed to ensure that the tracking error system is finite-time globally uniform ultimate bounded (GUUB) and the tracking error can converge into a compact set. Finally, it is validated that the proposed control method is effective through simulation studies.

Event-Triggered Finite-Time Trajectory Tracking Control for Quadrotor UAV Subjected to Time-Varying Output Constraints

Event-Triggered Finite-Time Trajectory Tracking Control for Quadrotor UAV Subjected to Time-Varying Output Constraints

Finite-time trajectory tracking control for unmanned ground vehicle based on finite-time disturbance observer

This paper studies the trajectory tracking problems of unmanned ground vehicle with model uncertainties and external disturbances. We propose a finite-time control method, in which the uncertainty and disturbance compensating is considered. To match the real motion scenarios of vehicles, the Frenet-coordinate system is used and the error dynamics equation is constructed. A new type of coordinate transformation is adopted to simplify the calculation of finite-time stability. Further, we design a new finite-time disturbance observer to deal with the model uncertainties and external disturbances. Based on this observer, the finite-time trajectory tracking controller is constructed by using a new integral-type Lyapunov function. It is theoretically proved that all tracking errors in the closed-loop system are finite-time stable. To verify the feasibility, simulation on the unmanned ground vehicle has been conducted.

Adaptive disturbance observer-based finite-time command filtered control of nonlinear systems

This article examines the finite-time trajectory tracking control problem for a category of nonlinear perturbed systems. A novel observation mechanism is constructed to mitigate the effects of complex system disturbances. Then, a new adaptive finite-time backstepping nonlinear control algorithm is designed by integrating this disturbance observer with a command filter method. The synthesized control strategy not only effectively suppresses external disturbances and avoids the differential explosion problem of traditional backstepping methods but also ensures the convergence of the trajectory tracking error and filtering error compensation signal within a finite time. Finally, the validity of the suggested approach is confirmed via comparative simulations.

An improved dynamic Prandtl–Ishlinskii hysteresis model and a PID-type adaptive sliding mode controller for piezoelectric micro-motion platform

Piezoelectric actuators are widely used in the field of micro-nano driving due to their advantages of fast frequency response, high displacement resolution, large stiffness, small size, and low heat generation. However, the hysteresis non-linearity of piezoelectric actuators severely affects their positioning accuracy during operation. Therefore, the study of hysteresis model and compensation control for piezoelectric actuators has always been a hot topic in the field of micro-nano driving. However, existing hysteresis models and control methods cannot well describe the dynamic hysteresis curve of piezoelectric actuators and track the desired trajectory. To address this issue, this paper proposes an improved dynamic Prandtl–Ishlinskii (IDPI) model and a finite-time trajectory tracking adaptive sliding mode control method based on PID-type. Firstly, this paper introduces the construction and parameter identification method of the IDPI model. Secondly, the accuracy of the IDPI model in describing hysteresis curves under different input signals is verified through experiments, and the effectiveness of the feedforward controller based on the IDPI model is validated experimentally. Then, considering the modeling uncertainty, unmodeled internal dynamics, and external environmental disturbances of the piezoelectric micro-motion platform, a finite-time trajectory tracking adaptive sliding mode controller based on PID-type is designed to suppress the non-linear characteristics of the piezoelectric micro-motion platform. Finally, the performance of the compensator is verified through simulation experiments.

Event-triggered finite-time fuzzy tracking control for a time-varying state constrained quadrotor system based on disturbance observer

In contrast with most existing results concerning quadrotor unmanned aerial vehicle (UAV) wherein time-triggered controllers or only symmetric state constraints are considered, this paper deals with the event-triggered finite-time trajectory tracking control problem for quadrotor UAV with asymmetric time-varying state constraints and unknown external disturbances. Firstly, the fuzzy logic system is used to approximate the nonlinear relationship of the quadrotor UAV system, and a disturbance observer is designed to compensate for composite disturbances. Secondly, the command filter and the event-triggered mechanism are introduced into the controller design, while asymmetric time-varying Lyapunov functions are constructed. Thus, the computational complexity and communication burden are reduced, and the event-triggered finite-time adaptive fuzzy controller is guaranteed to stabilize the quadrotor UAV in finite-time without violating all asymmetric time-varying state constraints. Finally, the simulation results demonstrate the validity of the proposed control strategy.

Performance-optimisation-based repetitive trajectory tracking control for autonomous farming vehicle

The high precision trajectory tracking for the autonomous farming vehicle (AFV) is closely related to work quality and crop yield. Farmland operations are usually repetitive tillages, and the farmland soil is relatively soft, slippery, and uneven, which can easily lead to uncertain problems such as slippage, parameter perturbation, and external disturbance. This paper proposes a finite-time repetitive trajectory tracking control strategy integrated with particle swarm optimisation (PSO) and equivalent input disturbance (EID) for the AFV to achieve performance optimisation. The repetitive control framework with finite-time convergence technique can effectively realise the iterative convergence performance of the repetitive trajectory tracking. The PSO algorithm is integrated into determining the control gains to optimise the dynamic and steady-state performances of the trajectory tracking control system. The EID method enhances the tracking precision and robustness to internal and external disturbances. Under MATLAB/Simulink and CarSim co-simulation environment, the effectiveness and advantages of the designed control strategy are illustrated by comparing it with the traditional repetitive control, the EID-based PI control, the active-disturbance-rejection-control-based nonsingular terminal sliding mode control, as well as the sliding-mode-observer-based integral sliding mode control strategies for a farming vehicle.

Finite-time control of uncertain Euler–Lagrange systems using ELM-based velocity observer

This paper is concerned with the finite-time trajectory tracking control of a class of Euler–Lagrange (EL) systems under unknown velocity information, dynamic uncertainties and disturbances. An extreme learning machine (ELM) algorithm is employed to approximate the uncertainties, while an adaptive algorithm is proposed to tune output weights of the ELM, as well as to eliminate the negative effects of residual errors and disturbances. Then an adaptive finite-time ELM-based velocity observer is developed to estimate the unavailable velocity states. Further, based on the estimations and the approximations of model uncertainties, an adaptive finite-time observer-based nonsingular terminal sliding mode (TSM) control strategy is constructed to guarantee the finite-time bounded tracking of the uncertain EL system by using the Lyapunov stability theorem. Simulation results on a robotic manipulator platform demonstrate the efficiency of the developed finite-time observation and control methods.

Order-supplementary finite-time trajectory tracking control of quadrotor unmanned aerial vehicles

Order-supplementary finite-time trajectory tracking control of quadrotor unmanned aerial vehicles

Trajectory tracking control of autonomous space-based simulators for the on-orbit assembly of large space optical telescopes

To enhance the precision of on-orbit assembly for large space optical telescopes, the control of attitude motion in the Autonomous Space-based Simulator (ASS) is imperative. This paper presents a robust finite-time trajectory tracking control method aimed at improving the position and attitude tracking performance of ASS. Considering the dynamic characteristics inherent in ASS, we introduce an improved non-singular fast terminal sliding mode controller (INFTSMC) incorporating an adaptive fuzzy mechanism to attain finite-time error convergence and robust control. The adaptive fuzzy logic control (AFLC) method yields an equivalent gain, eliminating discontinuous switching in terminal sliding mode control (TSMC). This reduction minimizes chattering in control inputs and compensates for uncertainties and time-varying disturbances within the dynamic model. The proposed method’s effectiveness is validated through comprehensive simulation and experimental studies.

Finite-time error convergent trajectory generation with field-of-view and angle constraints

Finite-time error convergent trajectory generation with field-of-view and angle constraints

Exponential fast terminal sliding mode based finite-time control of manipulator systems

A finite-time controller is designed based on an exponential fast terminal sliding mode for multi-joint manipulators, which solves the problem of slow convergence in trajectory tracking. By adding an exponential function on the basis of fast terminal sliding mode, the convergence speed is greatly improved. In addition, a new fast variable power reaching law is designed to reduce the chattering problem. The approaching speed is adjusted by changing the size of the power term adaptively in different stages of the approximation, so that the states of the system enter the sliding mode surface faster and more stablely. The controller realizes the finite-time trajectory tracking of the manipulator, shorens the convergence time and weakens the chattering frequency. Finally, the above views are verified by simulation and comparison experiments.

Adaptive Finite-Time Trajectory Tracking Control for Underactuated Surface Vehicles Based on Adaptive Disturbance Compensating

Adaptive Finite-Time Trajectory Tracking Control for Underactuated Surface Vehicles Based on Adaptive Disturbance Compensating

Discrete-Time Sliding Mode-Based Finite-Time Trajectory Tracking Control of Underactuated Surface Vessels With Large Sampling Periods

Discrete-Time Sliding Mode-Based Finite-Time Trajectory Tracking Control of Underactuated Surface Vessels With Large Sampling Periods

Barrier-Function Adaptive Finite-Time Trajectory Tracking Controls for Cyber Resilience in Smart Grids Under an Electricity Market Environment

Barrier-Function Adaptive Finite-Time Trajectory Tracking Controls for Cyber Resilience in Smart Grids Under an Electricity Market Environment

Rotation matrix-based finite-time trajectory tracking control of AUV with output constraints and input quantization

This study investigated a rotation-matrix-based finite-time trajectory tracking problem for autonomous underwater vehicles (AUVs) in the presence of output constraints, input quantization, and uncertainties. First, a rotation matrix-based attitude representation is introduced, which allow attitude dynamics to be globally and uniquely represented without unwinding. To satisfy the finite-time stability of AUV tracking control and the output constraints imposed by introducing the new attitude error vector, a novel finite-time command-filtered backstepping controller (FTCFBC) is proposed based on the asymmetrical time-varying barrier Lyapunov function (TVBLF). Subsequently, a second-order auxiliary dynamic system (ADS) is proposed to estimate the negative effects that of input quantization errors. Because the quantized control inputs can be switched at an appropriate earlier or later switching timing depending on the output of the ADS, the negative impact of quantization errors on the control accuracy is reduced. Moreover, an adaptive finite-time disturbance observer (AFTDO) is developed to estimate the lumped uncertainties without prior information on the bounds of the uncertainties. Finally, the results of the theoretical analysis verified that the tracking errors can converge within a finite time. Numerical simulations confirmed the effectiveness of the proposed control scheme.

Finite-Time Tracking Control of a Flexible Link Manipulator Based on an Extended State Observer

In this paper, the finite-time trajectory tracking control problem of a flexible link manipulator (FLM) system with unknown parameters is investigated in joint space. An adaptive nonsingular terminal sliding mode (ANTSM) controller based on an extended state observer (ESO) is proposed to ensure that the tracking error converges to a small neighborhood of zero. Firstly, an adaptive ESO is introduced, which is used to estimate unknown system parameters, including the unknown rigid-flexible coupling coefficient and the unknown control gain. Then, an ESO based on the parameters estimated above is proposed to estimate the unmodeled dynamics and external disturbances of the system in real-time. Finally, an ANTSM controller based on ESO is studied to achieve finite-time trajectory tracking control and vibration suppression without any prior knowledge of system uncertainties and external disturbances. The finite-time convergence ability of the closed-loop system is proved by Lyapunov theory. Experimental results on the Quanser Flexible Link System verify the effectiveness of the proposed controller.