scholarly journals Uncalibrated Visual Servoing for Underwater Vehicle Manipulator Systems with an Eye in Hand Configuration Camera

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5469 ◽  
Author(s):  
Jiyong Li ◽  
Hai Huang ◽  
Yang Xu ◽  
Han Wu ◽  
Lei Wan
Keyword(s):  
Visual Servoing ◽  
Degrees Of Freedom ◽  
Image Plane ◽  
Adaptive Controller ◽  
Underwater Vehicle ◽  
Lyapunov Theory ◽  
Time Varying ◽  
Position Information ◽  
Smooth Tracking ◽  
Uncalibrated Visual Servoing

This paper presents an uncalibrated visual servoing scheme for underwater vehicle manipulator systems (UVMSs) with an eye-in-hand camera under uncertainties. These uncertainties contain vision sensor parameters, UVMS kinematics and feature position information. At first, a linear separation approach is addressed to collect these uncertainties into vectors, and this approach can also be utilized in other free-floating based manipulator systems. Secondly, a novel nonlinear adaptive controller is proposed to achieve image error convergence by estimating these vectors, the gradient projection method is utilized to optimize the restoring moments. Thirdly, a high order disturbance observer is addressed to deal with time-varying disturbances, and the convergence of the image errors is proved under the Lyapunov theory. Finally, in order to illustrate the effectiveness of the proposed method, numerical simulations based on a 9 degrees of freedom (DOFs) UVMS with an eye-in-hand camera are conducted. In simulations, the UVMS is expected to track a circle trajectory on the image plane, meanwhile, time-varying disturbances are exerted on the system. The proposed scheme can achieve accurate and smooth tracking results during simulations.

Optimal Error-Clamping Design for Position-Based Visual Servoing of a 2-DOF Model Helicopter

2011 ◽  
Author(s):  
M. Alizadeh ◽  
C. Ratanasawanya ◽  
M. Mehrandezh ◽  
R. Paranjape
Keyword(s):  
Visual Servoing ◽  
Degrees Of Freedom ◽  
Vision System ◽  
Physical Space ◽  
Linear Quadratic Regulator ◽  
Image Plane ◽  
Reference Trajectory ◽  
Linear Quadratic ◽  
Feed Forward ◽  
Model Helicopter

A vision-based servoing technique is proposed for a 2 degrees-of-freedom (dof) model helicopter equipped with a monocular vision system. In general, these techniques can be categorized as image- and position-based, where the task error is defined in the image plane in the former and in the physical space in the latter. The 2-dof model helicopter requires a configuration-dependent feed-forward control to compensate for gravitational forces when servoing on a ground target. Therefore, a position-based visual servoing deems more appropriate for precision control. Image information collected from a ground object, with known geometry a priori, is used to calculate the desired pose of the camera and correspondingly the desired joint angles of the model helicopter. To assure a smooth servoing, the task error is parameterized, using the information obtained from the linearaized image Jacobian, and time scaled to form a moving reference trajectory. At the higher level, a Linear Quadratic Regulator (LQR), augmented with a feed-forward term and an integrator, is used to track this trajectory. The discretization of the reference trajectory is achieved by an error-clamping strategy for optimal performance. The proposed technique was tested on a 2-dof model helicopter capable of pitch and yaw maneuvers carrying a light-weight off-the-shelf video camera. The test results show that the optimized controller can servo the model helicopter to a hovering pose for an image acquisition rate of as low as 2 frames per second.

scholarly journals Adaptive Visually Servoed Tracking Control for Wheeled Mobile Robot with Uncertain Model Parameters in Complex Environment

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Fujie Wang ◽  
Yi Qin ◽  
Fang Guo ◽  
Bin Ren ◽  
John T. W. Yeow
Keyword(s):  
Mobile Robot ◽  
Visual Servoing ◽  
Dynamic Control ◽  
Kinematic Model ◽  
Image Plane ◽  
Adaptive Controller ◽  
Wheeled Mobile Robot ◽  
General Situation ◽  
Model Parameters ◽  
Complex Environment

This paper investigates the stabilization and trajectory tracking problem of wheeled mobile robot with a ceiling-mounted camera in complex environment. First, an adaptive visual servoing controller is proposed based on the uncalibrated kinematic model due to the complex operation environment. Then, an adaptive controller is derived to provide a solution of uncertain dynamic control for a wheeled mobile robot subject to parametric uncertainties. Furthermore, the proposed controllers can be applied to a more general situation where the parallelism requirement between the image plane and operation plane is no more needed. The overparameterization of regressor matrices is avoided by exploring the structure of the camera-robot system, and thus, the computational complexity of the controller can be simplified. The Lyapunov method is employed to testify the stability of a closed-loop system. Finally, simulation results are presented to demonstrate the performance of the suggested control.

scholarly journals Modeling and Control of the MARES Autonomous Underwater Vehicle

2010 ◽  
Vol 44 (2) ◽  
pp. 19-36 ◽  
Author(s):  
Bruno Ferreira ◽  
Aníbal Matos ◽  
Nuno Cruz ◽  
Miguel Pinto
Keyword(s):  
Degrees Of Freedom ◽  
Autonomous Underwater Vehicle ◽  
General Procedure ◽  
Underwater Vehicle ◽  
Underwater Vehicles ◽  
Lyapunov Theory ◽  
Control Laws ◽  
Modeling And Control ◽  
Definition Of ◽  
And Control

AbstractIn this work, we address the modeling and control problems in the domain of underwater vehicles. We focus on a prototype of an autonomous underwater vehicle. Although the work presented here is applied to a particular vehicle with four controllable degrees of freedom, the method may be easily extended to several submerged bodies. In the engineering area, modeling of systems is done frequently, as it yields a mathematical translation of their behavior. Since models can become an important tool to solve problems related to its motion or even to the design of controllers, we obtain a model with six degrees of freedom for such a vehicle.Robust control of underwater vehicles is an area in which many efforts were applied over the last two decades. However, due to nonlinear dynamics, it may be hard to design robust controllers that yield the expected behavior, and there is no general procedure to develop them. Here, we propose an approach that combines nonlinear controllers based on the deduced model and on the Lyapunov theory to control the velocities of the vehicle with linear controllers that control the vehicle’s position. We derive control laws to perform several maneuvers, both in the vertical and the horizontal planes, in a decoupled way, which is made possible through the configuration of thrusters. Finally, we present realistic simulations and experimental results that validate the proposed approach in the definition of the control laws.

Tracking Control of an Uncertain MEMS Resonator via Adaptive Terminal Sliding Mode Control

2013 ◽  
Vol 302 ◽  
pp. 665-670
Author(s):  
Chi Ching Yang ◽  
Rong Hao Guo
Keyword(s):  
Sliding Mode ◽  
Reference Signal ◽  
Sufficient Conditions ◽  
Adaptive Controller ◽  
Lyapunov Theory ◽  
Time Varying ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Mems Resonator ◽  
System Uncertainties

The purpose of this study is to develop the adaptive terminal sliding mode scheme to control a MEMS resonator with a six-powered potential function for tracking a given reference signal in the presence of system uncertainties and external disturbances. The proposed adaptive controller includes the time-varying feedback gains can tackle the nonlinear dynamics without directly eliminating. Meanwhile, these time-varying feedback gains are adaptively updated according to the suitable updated rules without the known bounds of system uncertainties and external disturbances. Some sufficient conditions to guarantee the stability based on Lyapunov theory and numerical simulations are performed to demonstrate the effectiveness of the presented scheme.

scholarly journals Application of Adaptive and Switching Control for Contact Maintenance of a Robotic Vehicle-Manipulator System for Underwater Asset Inspection

2021 ◽  
Vol 8 ◽  
Author(s):  
Kamil Cetin ◽  
Carlos Suarez Zapico ◽  
Harun Tugal ◽  
Yvan Petillot ◽  
Matthew Dunnigan ◽  
...  
Keyword(s):  
Contact Interaction ◽  
Degrees Of Freedom ◽  
Robot Manipulator ◽  
Adaptive Controller ◽  
Underwater Vehicle ◽  
Tracking Algorithm ◽  
Superior Performance ◽  
Physical Interaction ◽  
End Effector ◽  
Force Tracking

The aim of this study is to design an adaptive controller for the hard contact interaction problem of underwater vehicle-manipulator systems (UVMS) to realize asset inspection through physical interaction. The proposed approach consists of a force and position controller in the operational space of the end effector of the robot manipulator mounted on an underwater vehicle. The force tracking algorithm keeps the end effector perpendicular to the unknown surface of the asset and the position tracking algorithm makes it follow a desired trajectory on the surface. The challenging problem in such a system is to maintain the end effector of the manipulator in continuous and stable contact with the unknown surface in the presence of disturbances and reaction forces that constantly move the floating robot base in an unexpected manner. The main contribution of the proposed controller is the development of the adaptive force tracking control algorithm based on switching actions between contact and noncontact states. When the end effector loses contact with the surface, a velocity feed-forward augmented impedance controller is activated to rapidly regain contact interaction by generating a desired position profile whose speed is adjusted depending on the time and the point where the contact was lost. Once the contact interaction is reestablished, a dynamic adaptive damping-based admittance controller is operated for fast adaptation and continuous stable force tracking. To validate the proposed controller, we conducted experiments with a land robotic setup composed of a 6 degrees of freedom (DOF) Stewart Platform imitating an underwater vehicle and a 7 DOF KUKA IIWA robotic arm imitating the underwater robot manipulator attached to the vehicle. The proposed scheme significantly increases the contact time under realistic disturbances, in comparison to our former controllers without an adaptive control scheme. We have demonstrated the superior performance of the current controller with experiments and quantified measures.

Adaptive Control of a Sliding Seat Using Magnetorheological Energy Absorbers

2010 ◽  
Author(s):  
Min Mao ◽  
Norman M. Wereley ◽  
Alan L. Browne
Keyword(s):  
Adaptive Control ◽  
Degrees Of Freedom ◽  
Adaptive Controller ◽  
Degree Of Freedom ◽  
Lumped Mass ◽  
Adaptive Controllers ◽  
Bingham Number ◽  
Control Objective ◽  
Payload Mass ◽  
Energy Absorbers

Feasibility of a sliding seat utilizing adaptive control of a magnetorheological (MR) energy absorber (MREA) to minimize loads imparted to a payload mass in a ground vehicle for frontal impact speeds as high as 7 m/s (15.7 mph) is investigated. The crash pulse for a given impact speed was assumed to be a rectangular deceleration pulse having a prescribed magnitude and duration. The adaptive control objective is to bring the payload (occupant plus seat) mass to a stop using the available stroke, while simultaneously accommodating changes in impact velocity and occupant mass ranging from a 5th percentile female to a 95th percentile male. The payload is first treated as a single-degree-of-freedom (SDOF) rigid lumped mass, and two adaptive control algorithms are developed: (1) constant Bingham number control, and (2) constant force control. To explore the effects of occupant compliance on adaptive controller performance, a multi-degree-of-freedom (MDOF) lumped mass biodynamic occupant model was integrated with the seat mass. The same controllers were used for both the SDOF and MDOF cases based on SDOF controller analysis because the biodynamic degrees of freedom are neither controllable nor observable. The designed adaptive controllers successfully controlled load-stroke profiles to bring payload mass to rest in the available stroke and reduced payload decelerations. Analysis showed extensive coupling between the seat structures and occupant biodynamic response, although minor adjustments to the control gains enabled full use of the available stroke.

Visual servoing framework using Gaussian process for an aerial parallel manipulator

2018 ◽  
Vol 233 (9) ◽  
pp. 3408-3425
Author(s):  
Sungwook Cho ◽  
David Hyunchul Shim
Keyword(s):  
Gaussian Process ◽  
Parallel Manipulator ◽  
Visual Servoing ◽  
Degrees Of Freedom ◽  
Flight Test ◽  
Control Input ◽  
Body Velocity ◽  
Aerial Vehicle ◽  
Three Degrees Of Freedom ◽  
Traditional Image

This paper proposes a Gaussian process based visual servoing framework for an aerial parallel manipulator. Our aerial parallel manipulator utilizes the on-board eye-in-hand vision sensor system attached on the end-effector of three-degrees-of-freedom parallel manipulator. There are three major advantages: small, light in weight, and linearity with respect to the host vehicle rather than the serial manipulator, but it has a critical drawback that its workspace is too small to perform the mission itself during the hovering. In order to overcome the limited workspace problem and perform the mission more actively, proposed visual servoing framework is proposed to generate relative body velocity commands of the host vehicle by using the interpolated and extrapolated feature path between the initial and desired features to fed into the underactuated aerial parallel manipulator. It can generate not only numerical stable but also feasible control input. Furthermore, it can overcome the weakness of the traditional image-based visual servoing such as singularities, uncertainties, and local minimums during calculating image Jacobian under the large disparity environment between the target and the unmanned aerial vehicle. As a result of the proposed contribution, we show that our contribution is reliable to perform the picking-and-replacement autonomously, and it shows that it can be applied in the large displacement environments throughout the flight test.

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