scholarly journals Adaptive Event-Triggered Control Strategy for Ensuring Predefined Three-Dimensional Tracking Performance of Uncertain Nonlinear Underactuated Underwater Vehicles

Mathematics ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 137
Author(s):  
Jin Hoe Kim ◽  
Sung Jin Yoo
Keyword(s):  
Control Strategy ◽  
Dimensional Space ◽  
Error Function ◽  
Tracking Error ◽  
Three Dimensional ◽  
Underwater Vehicles ◽  
Tracking Performance ◽  
Control Scheme ◽  
Nonlinear Tracking ◽  
Event Triggered

This paper presents an adaptive event-triggered control strategy for guaranteeing predefined tracking performance of uncertain nonlinear underactuated underwater vehicles (UUVs) in the three-dimensional space. Compared with the related results in the literature, the main contribution of this paper is to develop a nonlinear error transformation approach for ensuring predefined three-dimensional tracking performance under the underactuated property of 6-DOF UUVs and limited network resources. A nonlinear tracking error function is designed using a linear velocity rotation matrix and a time-varying performance function. An adaptive event-triggered control scheme using the nonlinear tracking error function and neural networks is constructed to ensure the practical stability of the closed-loop system with predefined three-dimensional tracking performance. In the proposed control scheme, auxiliary stabilizing signals are designed to resolve the underactuated problem of UUVs. Simulation results are presented to illustrate the effectiveness of the theoretical methodology.

scholarly journals Nonlinear-Observer-Based Design Approach for Adaptive Event-Driven Tracking of Uncertain Underactuated Underwater Vehicles

Mathematics ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1144
Author(s):  
Jin Hoe Kim ◽  
Sung Jin Yoo
Keyword(s):  
Output Feedback ◽  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Error Function ◽  
Tracking Error ◽  
Three Dimensional ◽  
Output Feedback Control ◽  
Underwater Vehicles ◽  
Nonlinear Observer ◽  
Event Driven

A nonlinear-observer-based design methodology is proposed for an adaptive event-driven output-feedback tracking problem with guaranteed performance of uncertain underactuated underwater vehicles (UUVs) in six-degrees-of-freedom (6-DOF). A nonlinear observer using adaptive neural networks is presented to estimate the velocity information in the presence of unknown nonlinearities in the dynamics of 6-DOF UUVs where a state transformation approach using a time-varying scaling factor is introduced. Then, an output-feedback tracker using a nonlinear error function and estimated states is recursively designed to overcome the underactuated problem of the system dynamics and to guarantee preselected control performance in three-dimensional space. It is shown that the tracking error of the nonlinear-observer-based output-feedback control system exponentially converges a small neighbourhood around the zero. Efficiency of the resulting output-feedback strategy is verified through a simulation.

Iterative learning algorithm with a quadratic criterion for linear time-varying systems

2002 ◽  
Vol 216 (3) ◽  
pp. 309-316 ◽  
Author(s):  
S N Huang ◽  
K K Tan ◽  
T H Lee
Keyword(s):  
Learning Algorithm ◽  
Linear Time ◽  
Tracking Error ◽  
Iterative Learning ◽  
Tracking Performance ◽  
Time Varying ◽  
Control Scheme ◽  
Time Varying Systems ◽  
Simulation Results ◽  
Learning Law

A novel iterative learning controller for linear time-varying systems is developed. The learning law is derived on the basis of a quadratic criterion. This control scheme does not include package information. The advantage of the proposed learning law is that the convergence is guaranteed without the need for empirical choice of parameters. Furthermore, the tracking error on the final iteration will be a class K function of the bounds on the uncertainties. Finally, simulation results reveal that the proposed control has a good setpoint tracking performance.

Three-dimensional tracking control of autonomous underwater vehicles with limited torque and without velocity sensors

Robotica ◽  
2017 ◽  
Vol 36 (3) ◽  
pp. 374-394 ◽  
Author(s):  
Khoshnam Shojaei
Keyword(s):  
Tracking Control ◽  
Direct Method ◽  
Dimensional Space ◽  
Autonomous Underwater Vehicles ◽  
Three Dimensional ◽  
Underwater Vehicles ◽  
Estimation Errors ◽  
Trajectory Tracking Control ◽  
Environmental Disturbances ◽  
Control Signals

SUMMARYMost of the previous works on the motion control of autonomous underwater vehicles (AUVs) assume that (i) the vehicle actuators are able to tolerate every level of the control signals, and (ii) the vehicle is equipped with the velocity sensors in all degrees of freedom. These assumptions are not desirable in practice. Toward this end, this paper addresses the trajectory tracking control of the underactuated AUVs with the limited torque, without the velocity measurements and under environmental disturbances in a three-dimensional space. At first, a variable transformation is introduced which helps us to derive a second-order dynamic model for underactuated AUVs. Then, a saturated tracking controller is proposed by employing the saturation functions to bound the closed-loop error variables. This technique reduces the risk of the actuators saturation by decreasing the amplitude of the generated control signals. In addition, a nonlinear saturated observer is introduced to remove the velocity sensors from the control system. The proposed controller copes with the uncertain vehicle parameters, and constant or time-varying environmental disturbances induced by the waves and ocean currents. Lyapunov's direct method is used to show the semi-global uniform ultimate boundedness of the tracking and state estimation errors. Finally, some simulation results illustrate the effectiveness of the proposed controller.

scholarly journals Position/Force Tracking Impedance Control for Robotic Systems with Uncertainties Based on Adaptive Jacobian and Neural Network

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Jinzhu Peng ◽  
Zeqi Yang ◽  
Tianlei Ma
Keyword(s):  
Neural Network ◽  
Impedance Control ◽  
Tracking Error ◽  
Tracking Performance ◽  
Robotic Systems ◽  
Position Tracking ◽  
External Disturbances ◽  
Outer Loop ◽  
Control Scheme ◽  
Force Tracking

In this paper, an adaptive Jacobian and neural network based position/force tracking impedance control scheme is proposed for controlling robotic systems with uncertainties and external disturbances. To achieve precise force control performance indirectly by using the position tracking, the control scheme is divided into two parts: the outer-loop force impedance control and the inner-loop position tracking control. In the outer-loop, an improved impedance controller, which combines the traditional impedance relationship with the PID-like scheme, is designed to eliminate the force tracking error quickly and to reduce the force overshoot effectively. In this way, the satisfied force tracking performance can be achieved when the manipulator contacts with environment. In the inner-loop, an adaptive Jacobian method is proposed to estimate the velocities and interaction torques of the end-effector due to the system kinematical uncertainties, and the system dynamical uncertainties and the uncertain term of adaptive Jacobian are compensated by an adaptive radial basis function neural network (RBFNN). Then, a robust term is designed to compensate the external disturbances and the approximation errors of RBFNN. In this way, the command position trajectories generated from the outer-loop force impedance controller can be then tracked so that the contact force tracking performance can be achieved indirectly in the forced direction. Based on the Lyapunov stability theorem, it is proved that all the signals in closed-loop system are bounded and the position and velocity errors are asymptotic convergence to zero. Finally, the validity of the control scheme is shown by computer simulation on a two-link robotic manipulator.

scholarly journals Finite-Time Performance Guaranteed Event-Triggered Adaptive  Control for  Nonlinear Systems with Unknown Control Direction

2021 ◽  
Author(s):  
Min Wang ◽  
Lixue Wang
Keyword(s):  
Nonlinear Systems ◽  
Finite Time ◽  
Tracking Error ◽  
Tracking Performance ◽  
Performance Function ◽  
Time Performance ◽  
Unknown Control ◽  
Unknown Control Direction ◽  
Control Direction ◽  
Event Triggered

Abstract This paper studies the issue of finite-time performance guaranteed event-triggered (ET) adaptive neural tracking control for strict-feedback nonlinear systems with unknown control direction. A novel finite-time performance function is first constructed to describe the prescribed tracking performance, and then a new lemma is given to show the differentiability and boundedness for the performance function, which is important for the verification of the closed-loop stability. Furthermore, with the help of the error transformation technique, the origin constrained tracking error is transformed into an equivalent unconstrained one. By utilizing the first-order sliding mode differentiator, the issue of ``explosion of complexity'' caused by the backstepping design is adequately addressed. Subsequently, an ingenious adaptive updated law is given to co-design the controller and the ET mechanism by the combination of the Nussbaum-type function, thus effectively handling the influences of the measurement error resulted from the ET mechanism and the challenge of the controller design caused by the unknown control direction. The presented event-triggered control scheme can not only guarantee the prescribed tracking performance, but also alleviate the communication burden simultaneously. Finally, numerical and practical examples are provided to demonstrate the validity of the proposed control strategy.

scholarly journals VECTOR CONTROL SCHEME FOR INDUCTION MOTOR WITH DIFFERENT CONTROLLERS FOR NEGLECTING THE END EFFECTS IN HEV APPLICATIONS

2013 ◽  
pp. 243-249
Author(s):  
M. LAKSHMISWARUPA ◽  
G Tulasi Ram Das ◽  
P.V. RAJGOPAL
Keyword(s):  
Vector Control ◽  
Induction Motor ◽  
Control Strategy ◽  
Tracking Performance ◽  
Control Parameters ◽  
Control Task ◽  
End Effects ◽  
Proposed Model ◽  
Control Scheme ◽  
Parameter Variations

This paper develops the application of a different control strategy to the vector control of the voltage-fed induction motor. The proposed model decomposes the control task into three loops, namely, the speed loop, the d-axis flux loop and the q -axis flux loop. Then, tracking of speed with different controllers is designed for each loop. Proportional- Integral update laws are used to adjust the control parameters, which increases the tracking performance (Z-N Method) .Simulations are obtained shows good robustness against parameter variations, high tracking performance and simplicity of implementation.

scholarly journals Symmetric Kullback-Leibler Metric Based Tracking Behaviors for Bioinspired Robotic Eyes

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Hengli Liu ◽  
Jun Luo ◽  
Peng Wu ◽  
Shaorong Xie ◽  
Hengyu Li
Keyword(s):  
Particle Filtering ◽  
Parallel Mechanism ◽  
Tracking System ◽  
Error Function ◽  
Tracking Error ◽  
Robot Motion ◽  
Control Scheme ◽  
Smooth Tracking ◽  
Spherical Parallel Mechanism ◽  
Human Eyes

A symmetric Kullback-Leibler metric based tracking system, capable of tracking moving targets, is presented for a bionic spherical parallel mechanism to minimize a tracking error function to simulate smooth pursuit of human eyes. More specifically, we propose a real-time moving target tracking algorithm which utilizesspatial histogramstaking into account symmetric Kullback-Leibler metric. In the proposed algorithm, the key spatial histograms are extracted and taken into particle filtering framework. Once the target is identified, an image-based control scheme is implemented to drive bionic spherical parallel mechanism such that the identified target is to be tracked at the center of the captured images. Meanwhile, the robot motion information is fed forward to develop an adaptive smooth tracking controller inspired by theVestibuloocular Reflexmechanism. The proposed tracking system is designed to make the robot track dynamic objects when the robot travels through transmittable terrains, especially bumpy environment. To performbumpy-resist capabilityunder the condition of violent attitude variation when the robot works in the bumpy environment mentioned, experimental results demonstrate the effectiveness and robustness of our bioinspired tracking system using bionic spherical parallel mechanism inspired by head-eye coordination.

scholarly journals High Performance of an Adaptive Sliding Mode Controller under Varying Loads for Lifting-Type Autonomous Grounded Robot

2020 ◽  
Vol 10 (17) ◽  
pp. 5858
Author(s):  
Van Ngoc Son Huynh ◽  
Ha Quang Thinh Ngo ◽  
Thanh Phuong Nguyen ◽  
Hung Nguyen
Keyword(s):  
High Performance ◽  
Sliding Mode ◽  
Tracking Error ◽  
Autonomous Systems ◽  
Tracking Performance ◽  
Order System ◽  
Distribution Centers ◽  
Technical Problems ◽  
Adaptive Sliding Mode ◽  
Control Scheme

To work in shared space with humans, autonomous systems must carry unknown loads in predefined missions. With the conventional control scheme, the grounded robot would suffer unstable motion and imprecise tracking performance. To overcome these challenges, in this paper, a novel controller using an adaptive sliding mode for autonomous grounded robots (AGR) is proposed. This control strategy takes into consideration uncertain characteristics, varying loads, and external disturbances. To analyze the tracking performance precisely, the overall error of motion system is decoupled into two subsystems where the second-order system is related to the angular tracking error and the third-order system is associated with the linear one. Initially, the dynamics model of the grounded robot is established containing different elements of nonlinear forces in order to address the technical problems. Then, the system state equation of the autonomous system is mentioned to indicate the theoretical characteristics. Based on the proposed controller, the stability of the system is validated by the Lyapunov theorem. From the results of numerical tests, three practical situations consisting of separately linear and circular trajectories with varying loads and an S-curve trajectory of a working map are suggested. The tracking performance validates that the proposed control scheme is, in various scenarios, robust, effective, and feasible. From these superior outcomes, it can be determined obviously the property of our works in accommodating the variations of cargo from applications in distribution centers, material transportation, or handling equipment.

scholarly journals Observer Based Region Tracking Control for Underwater Vehicles Without Velocity Measurement

2021 ◽  
Author(s):  
Xing Liu ◽  
Mingjun Zhang ◽  
Feng Yao ◽  
Zhenzhong Chu
Keyword(s):  
Control Strategy ◽  
Velocity Measurement ◽  
Tracking Control ◽  
Rbf Neural Network ◽  
Tracking Error ◽  
High Gain ◽  
Underwater Vehicles ◽  
State Observer ◽  
Tracking Errors ◽  
Region Tracking

Abstract This paper addresses the problem of region tracking control for underwater vehicles without velocity measurement in marine environment. For this case, an improved region tracking control strategy is proposed based on a Nussbaum state observer. In the proposed method, a Nussbaum state observer is developed to estimate the unmeasured velocity of the vehicle. And then an improved region tracking control strategy is presented by incorporating the estimated results of the state observer, such that the tracking errors satisfy the requirement of the prescribed boundaries. In addition, a RBF neural network is applied to approximate the unknown dynamics of the vehicle. It is verified that the estimated error and the tracking error are uniformly ultimately bounded. Finally, the proposed observer-based region tracking control strategy is applied on an underwater vehicle to perform simulation studies and compared with a traditional backstepping controller and a traditional region tracking controller based on a high-gain observer. The comparative simulation results demonstrate the effectiveness of the proposed region tracking control strategy.

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