Dynamic Image-Based Visual Servo Control Using Centroid and Optic Flow Features

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
R. Mahony ◽  
P. Corke ◽  
T. Hamel
Keyword(s):  
Optic Flow ◽  
Closed Loop ◽  
Initial Conditions ◽  
Adaptive Estimation ◽  
Loop System ◽  
Servo Control ◽  
Visual Servo ◽  
Closed Loop System ◽  
Visual Servo Control ◽  
Vision Measurement

This paper considers the question of designing a fully image-based visual servo control for a class of dynamic systems. The work is motivated by the ongoing development of image-based visual servo control of small aerial robotic vehicles. The kinematics and dynamics of a rigid-body dynamical system (such as a vehicle airframe) maneuvering over a flat target plane with observable features are expressed in terms of an un-normalized spherical centroid and an optic flow measurement. The image-plane dynamics with respect to force input are dependent on the height of the camera above the target plane. This dependence is compensated by introducing virtual height dynamics and adaptive estimation in the proposed control. A fully nonlinear adaptive control design is provided that ensures asymptotic stability of the closed-loop system for all feasible initial conditions. The choice of control gains is based on an analysis of the asymptotic dynamics of the system. Results from a realistic simulation are presented that demonstrate the performance of the closed-loop system. To the author’s knowledge, this paper documents the first time that an image-based visual servo control has been proposed for a dynamic system using vision measurement for both position and velocity.

Application of Anytime Control to an Inherently Unstable Physical System

2015 ◽  
Author(s):  
Wayne Maxwell ◽  
Al Ferri ◽  
Bonnie Ferri
Keyword(s):  
Closed Loop ◽  
Initial Conditions ◽  
Transient Behavior ◽  
Open Loop ◽  
Loop System ◽  
Closed Loop System ◽  
Pendulum System ◽  
Inverted Pendulum System ◽  
Lqr Controller ◽  
Two Stages

This paper extends the use of closed-loop anytime control to systems that are inherently unstable in the open-loop. Previous work has shown that anytime control is very effective in compensating for occasional missed deadlines in the computer processor. When misses occur, the control law is truncated or partially executed. However, the previous work assumed that the open-loop system was stable. In this paper, the anytime strategy is applied to an inverted pendulum system. An LQR controller with estimated state feedback is designed and decomposed into two stages. Both stages are implemented most of the time, but in a small percentage of time, only the first stage is applied, with the resulting closed-loop system being unstable for short periods of time. The statistical performance of the closed-loop system is studied using Monte-Carlo simulations. It is seen that, on average, the closed-loop performance is very close to that of the full-order controller as long as the miss rate is relatively small. However, the variance of the response shows much higher dependence on the miss rate, suggesting that the response becomes more unpredictable. At a critical value of miss rate, the closed-loop system is unstable. The critical miss rate found through simulation is seen to correlate well with the results of a deterministic stability analysis. The statistics on the settling time are also studied, and shown to grow longer as the miss rate increases. The transient behavior of the system is studied for a range of initial conditions.

Nonlinear Vision-Based Observer for Visual Servo Control of an Aerial Robot in Global Positioning System Denied Environments

2018 ◽  
Vol 10 (6) ◽  
Author(s):  
Dejun Guo ◽  
Hesheng Wang ◽  
Kam K. Leang
Keyword(s):  
Global Positioning System ◽  
Closed Loop ◽  
Servo Control ◽  
Nonlinear Observer ◽  
Positioning System ◽  
Visual Servo ◽  
Visual Servo Control ◽  
Global Positioning ◽  
The World ◽  
Aerial Robot

This paper presents a nonlinear vision-based observer to estimate 3D translational position and velocity of a quadrotor aerial robot for closed-loop, position-based, visual-servo control in global positioning system (GPS)-denied environments. The method allows for motion control in areas where GPS signals are weak or absent, for example, inside of a building. Herein, the robot uses a low-cost on-board camera to observe at least two feature points fixed in the world frame to self-localize for feedback control, without constraints on the altitude of the robot. The nonlinear observer described takes advantage of the geometry of the perspective projection and is designed to update the translational position and velocity in real-time by exploiting visual information and information from an inertial measurement unit. One key advantage of the algorithm is it does not require constraints or assumptions on the altitude and initial estimation errors. Two new controllers based on the backstepping technique that take advantage of the estimator's output are described and implemented for trajectory tracking. The Lyapunov method is used to show asymptotic stability of the closed-loop system. Simulation and experimental results from an indoor environment where GPS localization is not available are presented to demonstrate feasibility and validate the performance of the observer and control system for hovering and tracking a circular trajectory defined in the world frame.

HAND–EYE COORDINATION THROUGH ENDPOINT CLOSED-LOOP AND LEARNED ENDPOINT OPEN-LOOP VISUAL SERVO CONTROL

2005 ◽  
Vol 02 (02) ◽  
pp. 203-224 ◽  
Author(s):  
CHRIS GASKETT ◽  
ALEŠ UDE ◽  
GORDON CHENG
Keyword(s):  
Visual Cues ◽  
Closed Loop ◽  
Open Loop ◽  
Servo Control ◽  
Visual Servo ◽  
Visual Servo Control ◽  
Motor Mapping ◽  
Hand Eye Coordination ◽  
Coordination System ◽  
Bimanual Reaching

We propose a hand-eye coordination system for a humanoid robot that supports bimanual reaching. The system combines endpoint closed-loop and open-loop visual servo control. The closed-loop component moves the eyes, head, arms, and torso, based on the position of the target and the robot's hands, as seen by the robot's head-mounted cameras. The open-loop component uses a motor-motor mapping that is learnt online to support movement when visual cues are not available.

Position and Linear Velocity Estimation for Position-Based Visual Servo Control of an Aerial Robot in GPS-Denied Environments

2017 ◽  
Author(s):  
Dejun Guo ◽  
Kam K. Leang
Keyword(s):  
Closed Loop ◽  
Tall Buildings ◽  
Linear Velocity ◽  
Servo Control ◽  
Adaptive Observer ◽  
Visual Servo ◽  
Visual Servo Control ◽  
The World ◽  
Aerial Robot ◽  
Velocity Information

This paper presents a new nonlinear adaptive vision-based observer to estimate position and linear velocity information for closed-loop position-based visual servo control of an aerial robot in GPS-denied environments. Specifically, the observer determines the position and linear velocity of the robot for closed-loop control by observing using a low-cost on-board camera at least two feature points fixed in the world frame. The nonlinear adaptive observer takes advantage of the geometry of perspective projection, and is designed to update position and velocity information in real-time. Thus, there are no constraints or assumptions on the depth and initial estimation errors. Furthermore, the proposed parameter estimator addresses the challenge in situations where GPS signals may be weak, unreliable, or nonexistent, such in valleys, canyons, and between tall buildings, or inside of a building and under dense canopy. For closed-loop tracking control using the estimated position and velocity information, a backstepping controller is employed for the underactuated aerial robot system. The Lyapunov method is used to show stability of the closed-loop system. Simulation and experimental results are presented that validate the performance of the observer and control system for hovering and tracking a circular trajectory, where both are defined in the world (lab) frame.

scholarly journals Exponential stability of axially moving Kirchhoff-beam systems with nonlinear boundary damping and disturbance

2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Yi Cheng ◽  
Zhihui Dong ◽  
Donal O' Regan
Keyword(s):  
Exponential Stability ◽  
Closed Loop ◽  
Initial Conditions ◽  
Galerkin Approximation ◽  
Nonlinear Damping ◽  
Loop System ◽  
Direct Lyapunov Method ◽  
Closed Loop System ◽  
Uniqueness Of Solutions ◽  
Axially Moving

<p style='text-indent:20px;'>This paper examines the stabilization problem of the axially moving Kirchhoff beam. Under the nonlinear damping criterion established by the slope-restricted condition, the existence and uniqueness of solutions of the closed-loop system equipped with nonlinear time-delay disturbance at the boundary is investigated via the Faedo-Galerkin approximation method. Furthermore, the solution is continuously dependent on initial conditions. Then the exponential stability of the closed-loop system is established by the direct Lyapunov method, where a novel energy function is constructed.</p>

A Research of Image-Based Visual Control in Microassembly under a Microscope

2006 ◽  
Vol 315-316 ◽  
pp. 809-812
Author(s):  
Shi Jie Tian ◽  
B. Li ◽  
Zhuang De Jiang ◽  
Jun Jie Guo ◽  
H.Y. Zhao
Keyword(s):  
Control System ◽  
Control Algorithm ◽  
Closed Loop ◽  
High Reliability ◽  
Visual Control ◽  
Servo Control ◽  
Robot Kinematics ◽  
Visual Servo ◽  
Visual Servo Control ◽  
Servo Control System

A new visual servo control system under microscope was introduced based on the research of image-based computer visual control system, including the installation and calibration of camera, deduction of the image Jacobian and the algorithm of controlling and so on. The experiments of motion controlling and positioning showed that one pixel about 2.97μm can be reached easily in single axes under 5× eyepiece and under the same condition a 400μm micro shaft was assembled into a micro-gear with 415μm inner bore. Knowing from the control algorithm, the accuracy of the system is independent on errors in the robot kinematics or the camera calibration. The research results indicate that this method is a full closed-loop visual servo control system with a high reliability and simple control algorithm and it can be used in microassembly system.

Safety and Performance of the Omnipod®Hybrid Closed-Loop System in Adolescents with Type 1 Diabetes over Five Days Under Free-Living Conditions

Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 1376-P
Author(s):  
GREGORY P. FORLENZA ◽  
BRUCE BUCKINGHAM ◽  
JENNIFER SHERR ◽  
THOMAS A. PEYSER ◽  
JOON BOK LEE ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Closed Loop ◽  
Living Conditions ◽  
Loop System ◽  
Closed Loop System ◽  
Free Living ◽  
And Performance ◽  
Free Living Conditions

1066-P: Improvement in Time-in-Range (TIR) with Real-Life Use of Hybrid Closed-Loop System in Patients with Type 1 Diabetes (T1D)

Diabetes ◽  
2019 ◽  
Vol 68 (Supplement 1) ◽  
pp. 1066-P
Author(s):  
HALIS K. AKTURK ◽  
DOMINIQUE A. GIORDANO ◽  
HAL JOSEPH ◽  
SATISH K. GARG ◽  
JANET K. SNELL-BERGEON
Keyword(s):  
Type 1 Diabetes ◽  
Closed Loop ◽  
Real Life ◽  
Loop System ◽  
Closed Loop System ◽  
Time In Range
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