scholarly journals Image-based Visual Servoing for Optimal Grasping

2001 ◽  
Vol 13 (5) ◽  
pp. 479-487
Author(s):  
Hideo Fujimoto ◽  
◽  
Liu-Cun Zhu ◽  
Karim Abdel-Malek ◽  
Keyword(s):  
Visual Servoing ◽  
Ccd Camera ◽  
Servo Control ◽  
Visually Guided ◽  
Grasp Planning ◽  
Vector Processing ◽  
Vector Error ◽  
Proposed Model ◽  
Control Scheme ◽  
Kinematic Errors

One of the most common tasks in robotics is grasping. Although the formulation of optimal grasping has been addressed using a variety of approaches, there are only a few grasping systems that can operate in uncertain dynamic environments. In this paper, we present an image-based visual servoing method and system for optimal object grasping by introducing the method of visual vectors. A CCD camera mounted on a robot end-effector constructs the visually guided servo control system and the control scheme lends itself to task-level specification of manipulation goals. The proposed approach integrates vision, grasp planning, and vision=guided control to accomplish the optimal grasping task. The grasping task is to control the robot so the vectors of the end-effector's landmark (e.g., finger vector) and a target object's grasp coincide. These vectors can be used to perform the work of a stable grasping of an object that is presented in an unstructured manner. Visual vectors in image frame are obtained by analyzing the object's image and projection. Our objective in implementing vector processing is to estimate the vector error between the finger and grasp vectors, and to control the robot to eliminate kinematic errors. The proposed model is illustrated through examples and its effectiveness is validated using computer simulation.

scholarly journals A Study on Vision-Based Backstepping Control for a Target Tracking System

Actuators ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 105
Author(s):  
Thinh Huynh ◽  
Minh-Thien Tran ◽  
Dong-Hun Lee ◽  
Soumayya Chakir ◽  
Young-Bok Kim
Keyword(s):  
Control System ◽  
Visual Servoing ◽  
Tracking System ◽  
Experimental Studies ◽  
Imaging Geometry ◽  
Control Scheme ◽  
Decoupled Control ◽  
Control Configuration ◽  
A New Technique ◽  
Pointing Control

This paper proposes a new method to control the pose of a camera mounted on a two-axis gimbal system for visual servoing applications. In these applications, the camera should be stable while its line-of-sight points at a target located within the camera’s field of view. One of the most challenging aspects of these systems is the coupling in the gimbal kinematics as well as the imaging geometry. Such factors must be considered in the control system design process to achieve better control performances. The novelty of this study is that the couplings in both mechanism’s kinematics and imaging geometry are decoupled simultaneously by a new technique, so popular control methods can be easily implemented, and good tracking performances are obtained. The proposed control configuration includes a calculation of the gimbal’s desired motion taking into account the coupling influence, and a control law derived by the backstepping procedure. Simulation and experimental studies were conducted, and their results validate the efficiency of the proposed control system. Moreover, comparison studies are conducted between the proposed control scheme, the image-based pointing control, and the decoupled control. This proves the superiority of the proposed approach that requires fewer measurements and results in smoother transient responses.

scholarly journals 2D Legendre Moments-Based Visual Control

2012 ◽  
Vol 162 ◽  
pp. 487-496 ◽  
Author(s):  
Aurelien Yeremou Tamtsia ◽  
Youcef Mezouar ◽  
Philippe Martinet ◽  
Haman Djalo ◽  
Emmanuel Tonye
Keyword(s):  
Visual Servoing ◽  
Dynamic Range ◽  
High Sensitivity ◽  
High Dynamic Range ◽  
Interaction Matrix ◽  
Geometric Moments ◽  
Control Scheme ◽  
Control Schemes ◽  
Legendre Moments ◽  
Set Of Points

Among region-based descriptors, geometric moments have been widely exploited to design visual servoing schemes. However, they present several disadvantages such as high sensitivity to noise measurement, high dynamic range and information redundancy (since they are not computed onto orthogonal basis). In this paper, we propose to use a class of orthogonal moments (namely Legendre moments) instead of geometric moments to improve the behavior of moment-based control schemes. The descriptive form of the interaction matrix related to the Legendre moments computed from a set of points is rst derived. Six visual features are then selected to design a partially-decoupled control scheme. Finally simulated and experimental results are presented to illustrate the validity of our proposal.

A Novel Error Equivalence Model on the Kinematic Error of the Linear Axis of High-End Machine Tool

2021 ◽  
Author(s):  
Xinxin LI ◽  
Zhi-Min Li ◽  
Sun Jin ◽  
Jichang Zhang ◽  
Siyi Ding ◽  
...  
Keyword(s):  
Machine Tool ◽  
Elastic Deformation ◽  
Numerical Control ◽  
Small Displacement ◽  
Kinematic Error ◽  
Guide Rail ◽  
Linear Guide ◽  
Proposed Model ◽  
Equivalence Model ◽  
Kinematic Errors

Abstract The kinematic errors of the linear axis play a key role in machining precision of high-end CNC (Computer Numerical Control) machine tool. The quantification of error relationship is still an urgent problem to be solved in the assembly process of the linear axis, especially considering the effect of the elastic deformation of rollers. A systematic error equivalence model of slider is proposed to improve the prediction accuracy for kinematic errors of the linear axis which contains the base, the linear guide rail and carriage. Firstly, the geometric errors of assembly surface of linear guide rail are represented by small displacement torsor. According to the theory of different motion of robots, the error equivalence model of a single slider is established, namely the geometric error of assembly surface of linear guide rail and the pose error of slider is equivalent to the elastic deformation of roller. Based on the principle of vector summation, the kinematic error of a single slider is mapped to the carriage and the kinematic error of the linear axis is obtained. Besides, experiments validation of kinematic error model of the linear axis is carried out. It is indicated that the proposed model is accurate and feasible. The proposed model can provide an accurate guidance for the manufacturing and operation performance of the linear axis in quantification, and a more effective reference for the engineers at the design and assembly stage.

Uniform ultimate bounded robust model reference adaptive PID control scheme for visual servoing

2017 ◽  
Vol 354 (4) ◽  
pp. 1741-1758 ◽  
Author(s):  
Raaja Ganapathy Subramanian ◽  
Vinodh Kumar Elumalai ◽  
Selvakumar Karuppusamy ◽  
Vamsi Krishna Canchi
Keyword(s):  
Pid Control ◽  
Visual Servoing ◽  
Model Reference ◽  
Robust Model ◽  
Control Scheme ◽  
Adaptive Pid Control ◽  
Model Reference Adaptive

scholarly journals Grasp Planning and Visual Servoing for an Outdoors Aerial Dual Manipulator

Engineering ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 77-88
Author(s):  
Pablo Ramon-Soria ◽  
Begoña C. Arrue ◽  
Anibal Ollero
Keyword(s):  
Visual Servoing ◽  
Grasp Planning

From motor to visually guided bimanual affordance learning

2019 ◽  
Vol 28 (2) ◽  
pp. 63-78 ◽  
Author(s):  
Martí Sánchez-Fibla ◽  
Sébastien Forestier ◽  
Clément Moulin-Frier ◽  
Jordi-Ysard Puigbò ◽  
Paul FMJ Verschure
Keyword(s):  
Visual Servoing ◽  
Learning Approaches ◽  
Visually Guided ◽  
Perceptual Cues ◽  
Motor Equivalence ◽  
Field Gradients ◽  
Bimanual Interaction ◽  
Event Based ◽  
And Behavior ◽  
The Brain

The mechanisms of how the brain orchestrates multi-limb joint action have yet to be elucidated and few computational sensorimotor (SM) learning approaches have dealt with the problem of acquiring bimanual affordances. We propose a series of bidirectional (forward/inverse) SM maps and its associated learning processes that generalize from uni- to bimanual interaction (and affordances) naturally, reinforcing the motor equivalence property. The SM maps range from a SM nature to a solely sensory one: full body control, delta SM control (through small action changes), delta sensory co-variation (how body-related perceptual cues covariate with object-related ones). We make several contributions on how these SM maps are learned: (1) Context and Behavior-Based Babbling: generalizing goal babbling to the interleaving of absolute and local goals including guidance of reflexive behaviors; (2) Event-Based Learning: learning steps are driven by visual, haptic events; and (3) Affordance Gradients: the vectorial field gradients in which an object can be manipulated. Our modeling of bimanual affordances is in line with current robotic research in forward visuomotor mappings and visual servoing, enforces the motor equivalence property, and is also consistent with neurophysiological findings like the multiplicative encoding scheme.

Aeroelastic Suppression of Wind Turbine Blade Using Trailing-Edge Flap

2013 ◽  
Author(s):  
Nailu Li ◽  
Mark J. Balas
Keyword(s):  
Adaptive Control ◽  
Wind Turbine ◽  
Stability Theorem ◽  
Time Varying ◽  
Aeroelastic System ◽  
Aerodynamic Loads ◽  
Proposed Model ◽  
Control Scheme ◽  
Trailing Edge Flap ◽  
Adaptive Control Scheme

The variation of aeroelastic system dynamics is treated as the change of time-varying aerodynamic loads along the operation trajectory of a spinning wind turbine. An Adaptive Control scheme is introduced to suppress flutter based on the proposed model. The robustness and effectiveness of Adaptive Control is shown by simulation results. For stability analysis, Adaptive Stability Theorem is proved theoretically by Kalman-Yacubovic Lemma and demonstrated numerically by certain cases.

scholarly journals A decentralized control scheme for orchestrating versatile arm movements in ophiuroid omnidirectional locomotion

2011 ◽  
Vol 9 (66) ◽  
pp. 102-109 ◽  
Author(s):  
Wataru Watanabe ◽  
Takeshi Kano ◽  
Shota Suzuki ◽  
Akio Ishiguro
Keyword(s):  
Decentralized Control ◽  
Coupled Oscillators ◽  
Design Methodology ◽  
Arm Movements ◽  
Rhythmic Movements ◽  
Role Assignment ◽  
Rotator Model ◽  
Proposed Model ◽  
Control Scheme ◽  
Living Organisms

Autonomous decentralized control is a key concept for understanding the mechanism underlying the adaptive and versatile behaviour of animals. Although the design methodology of decentralized control based on a dynamical system approach that can impart adaptability by using coupled oscillators has been proposed in previous studies, it cannot reproduce the versatility of animal behaviours comprehensively. Therefore, our objective is to understand behavioural versatility from the perspective of well-coordinated rhythmic and non-rhythmic movements. To this end, we focus on ophiuroids as a simple good model of living organisms that exhibit spontaneous role assignment of rhythmic and non-rhythmic arm movements, and we model such arm movements by using an active rotator model that can describe both oscillatory and excitatory properties. Simulation results show that the spontaneous role assignment of arm movements is successfully realized by using the proposed model, and the simulated locomotion is qualitatively equivalent to the locomotion of real ophiuroids. This fact can potentially facilitate a better understanding of the control mechanism responsible for the orchestration of versatile arm movements in ophiuroid omnidirectional locomotion.

Analysis of an Opto-Pneumatic Control System and Improvement of its Control Performance

1999 ◽  
Vol 11 (4) ◽  
pp. 251-257 ◽  
Author(s):  
Tetsuya Akagi ◽  
◽  
Shujiro Dohta ◽  
Hisashi Matsushita ◽  
Keyword(s):  
Control System ◽  
Position Control ◽  
Sliding Mode ◽  
Pneumatic Cylinder ◽  
Control Performance ◽  
Pneumatic Control ◽  
Servo Valve ◽  
Proposed Model ◽  
Control Scheme

This paper describes an analysis of an opto-pneumatic control system and an improvement of control performance of the system. The opto-pneumatic system consists of an optical servo valve, a pneumatic cylinder and a cart. First, we built an analytical model of the system considering a nonlinear friction where exists in sliding parts. And we confirmed the validity of the proposed model by comparing theoretical results with experimental results of the characteristics of optical servo valve and cart position control. Then, we applied a sliding mode control scheme compensating a steady-state disturbance to multi- position control and follow-up control of a cart. By computer simulation, we confirmed that the control performance of opto-pneumatic control system was improved by using this control scheme.

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