Underactuated Part Alignment System (UPAS) for Industrial Assembly Tasks

2011 ◽  
Author(s):  
Brian J. Slaboch ◽  
Philip Voglewede
Keyword(s):  
Degrees Of Freedom ◽  
Vertical Plane ◽  
Cost Effective ◽  
Robotic Assembly ◽  
Robot Arm ◽  
Planning Techniques ◽  
Alignment System ◽  
Compliant Assembly ◽  
Industrial Assembly ◽  
Assembly Tasks

This paper introduces the Underactuated Part Alignment System (UPAS) as a cost-effective and flexible approach to aligning parts in the vertical plane prior to an industrial robotic assembly task. The advantage of the UPAS is that it utilizes the degrees of freedom (DOFs) of a SCARA (Selective Compliant Assembly Robot Arm) type robot in conjunction with an external fixed post to achieve the desired part alignment. Three path planning techniques will be presented that can be used with the UPAS to achieve the proper part rotation.

Underactuated Part Alignment System for Industrial Assembly Applications

2012 ◽  
Vol 5 (1) ◽  
Author(s):  
Brian J. Slaboch ◽  
Philip A. Voglewede
Keyword(s):  
Laboratory Testing ◽  
Degrees Of Freedom ◽  
Vertical Plane ◽  
Cost Effective ◽  
Robotic Assembly ◽  
Robot Arm ◽  
Planning Techniques ◽  
Alignment System ◽  
Compliant Assembly ◽  
Industrial Assembly

This paper introduces the underactuated part alignment system (UPAS) as a cost-effective and flexible approach to aligning parts in the vertical plane prior to an industrial robotic assembly task. The advantage of the UPAS is that it utilizes the degrees of freedom (DOFs) of a SCARA (selective compliant assembly robot arm) type robot in conjunction with an external fixed post to achieve the desired part alignment. Additionally, the UPAS is not constrained to work with rigid, polygonal parts. Three path planning techniques are presented that can be used with the UPAS to achieve the proper part rotation. The results from laboratory testing show that the UPAS can be used to consistently achieve the desired part rotation to within 0.5% of the desired value.

scholarly journals Towards Autonomous Robotic Assembly: Using Combined Visual and Tactile Sensing for Adaptive Task Execution

2021 ◽  
Vol 101 (3) ◽  
Author(s):  
Korbinian Nottensteiner ◽  
Arne Sachtler ◽  
Alin Albu-Schäffer
Keyword(s):  
Autonomous Robots ◽  
Vision System ◽  
Dynamic Environments ◽  
Bayesian Framework ◽  
Experimental Results ◽  
Robotic Assembly ◽  
Tactile Sensing ◽  
Task Execution ◽  
Industrial Assembly ◽  
Assembly Tasks

AbstractRobotic assembly tasks are typically implemented in static settings in which parts are kept at fixed locations by making use of part holders. Very few works deal with the problem of moving parts in industrial assembly applications. However, having autonomous robots that are able to execute assembly tasks in dynamic environments could lead to more flexible facilities with reduced implementation efforts for individual products. In this paper, we present a general approach towards autonomous robotic assembly that combines visual and intrinsic tactile sensing to continuously track parts within a single Bayesian framework. Based on this, it is possible to implement object-centric assembly skills that are guided by the estimated poses of the parts, including cases where occlusions block the vision system. In particular, we investigate the application of this approach for peg-in-hole assembly. A tilt-and-align strategy is implemented using a Cartesian impedance controller, and combined with an adaptive path executor. Experimental results with multiple part combinations are provided and analyzed in detail.

Numerical Model of Towing Line in Sea Transport

2014 ◽  
Author(s):  
Ivan Ćatipović ◽  
Nastia Degiuli ◽  
Andreja Werner ◽  
Većeslav Čorić ◽  
Jadranka Radanović
Keyword(s):  
Numerical Model ◽  
Time Domain ◽  
Degrees Of Freedom ◽  
Vertical Plane ◽  
Cost Effective ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Sea Transport ◽  
Nonlinear Properties ◽  
Wave Induced

Towing as a specific type of sea transport is often used for installing objects for drilling and exploitation of underwater gas and oil wells. Also, towing proved to be a cost-effective solution for the installation of the offshore wind turbine electric generators at sea locations. Because of the mass of these objects the need for towing increases progressively. Time domain numerical model for the wave-induced motions of a towed ship and the towline tension in regular head seas is presented in this paper. For the sake of simplicity, one end of the towing line is attached to ship’s bow and another end has prescribed straight line motion. All considerations are done in the vertical plane so the ship is modeled as a rigid body with three degrees of freedom. Hydrodynamic loadings due to waves are taken into account along with added mass and damping. Dynamics of the towing line is described by finite elements. Due to the nonlinear properties of the problem calculations are done in time domain. Comparison of the obtained numerical results is made with previously published results.

Analysis and simulation of a new Cartesian cable-suspended robot

2009 ◽  
Vol 224 (8) ◽  
pp. 1717-1726 ◽  
Author(s):  
G Castelli ◽  
E Ottaviano ◽  
A González
Keyword(s):  
Numerical Simulation ◽  
Degrees Of Freedom ◽  
Robot Arm ◽  
Fixed Frame ◽  
Cartesian Space ◽  
Compliant Assembly ◽  
Moving Platform ◽  
Geometry Analysis ◽  
Three Degrees Of Freedom

In this article, a manipulator is presented belonging to the class of cable-suspended robots, for which the cable length variations are related by suitable functions in order to achieve specific kinematic characteristics. In particular, in this article, a Cartesian cable-suspended robot is proposed that has eight cables to have three degrees of freedom (DOF) in Cartesian space. The eight cables of the robot are arranged in parallel by pairs with identical length, with the aim of constraining the moving platform to keep a constant orientation with respect to the fixed frame. The robot can be used for selective compliant assembly robot arm (SCARA) motions (when an additional revolute actuated joint is placed on the moving platform) for a variety of applications in which a large workspace is required. In this article, a geometry analysis of the robot is presented together with a numerical simulation of the kinetostatics and dynamics to investigate the robot's performances in several operative conditions. Furthermore, a characterization of the position workspace regions is reported for this cable-suspended robot.

Fuzzy Predictive Control Using Particle Swarm Optimization: Application to SCARA Robot

2014 ◽  
Vol 527 ◽  
pp. 230-236
Author(s):  
Mohamed Laid Hadjili ◽  
Kamel Kara ◽  
Oussama Ait Sahed ◽  
Jamal Bouyanzar
Keyword(s):  
Particle Swarm Optimization ◽  
Predictive Control ◽  
Degrees Of Freedom ◽  
Particle Swarm ◽  
Fuzzy Model ◽  
Robot Arm ◽  
Swarm Optimization ◽  
Modified Particle Swarm Optimization ◽  
Compliant Assembly ◽  
Fuzzy Predictive Control

In this work a fuzzy model-based predictive control (FMPC) method that uses modified particle swarm optimization (PSO) is presented. The main objective of this work is the application of this method to the control of a Selective Compliant Assembly Robot Arm (SCARA) with four degrees of freedom (4-DOF).

Single camera-based synchronisation within a concept of robotic assembly in motion

2014 ◽  
Vol 34 (2) ◽  
pp. 160-168 ◽  
Author(s):  
Robert Schmitt ◽  
Yu Cai
Keyword(s):  
Degrees Of Freedom ◽  
Robotic Assembly ◽  
Cylinder Block ◽  
Camera System ◽  
Trajectory Estimation ◽  
Content Type ◽  
Positioning Systems ◽  
Monocular Camera ◽  
Distant Field ◽  
Assembly Tasks

Purpose – Automated robotic assembly on a moving workpiece, referred to as assembly in motion, demands that an assembly robot is synchronised in all degrees of freedom to the moving workpiece, on which assembly parts are installed. Currently, this requirement cannot be met due to the lack of robust estimation of 3D positions and the trajectory of the moving workpiece. The purpose of this paper is to develop a camera system that measures the 3D trajectory of the moving workpiece for robotic assembly in motion. Design/methodology/approach – For the trajectory estimation, an assembly robot-guided, monocular camera system is developed. The motion trajectory of a workpiece is estimated, as the trajectory is considered as a linear combination of trajectory bases, such as discrete cosine transform bases. Findings – The developed camera system for trajectory estimation is tested within the robotic assembly of a cylinder block in motion. The experimental results show that the proposed method is able to reconstruct arbitrary trajectories of an assembly point on a workpiece moving in 3D space. Research limitations/implications – With the developed technology, a point trajectory can be recovered offline only after all measurement images are acquired. For practical assembly tasks in real production, this method should be extended to determine the trajectory online during the motion of a workpiece. Practical implications – For practical, robotic assembly in motion, such as assembling tires, wheels and windscreens on conveyed vehicle bodies, the developed technology can be used for positioning a moving workpiece, which is in the distant field of an assembly robot. Originality/value – Besides laser trackers, indoor global positioning systems and stereo cameras, this paper provides a solution of trajectory estimation by using a monocular camera system.

scholarly journals High-Speed Autonomous Robotic Assembly Using In-Hand Manipulation and Re-Grasping

2020 ◽  
Vol 11 (1) ◽  
pp. 37
Author(s):  
Taewoong Kang ◽  
Jae-Bong Yi ◽  
Dongwoon Song ◽  
Seung-Joon Yi
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Robotic Assembly ◽  
Robotic Arm ◽  
Assembly System ◽  
Multi Stage ◽  
Assembly Sequences ◽  
Motion Sequence ◽  
The Individual ◽  
Assembly Tasks

This paper presents an autonomous robotic assembly system for Soma cube blocks, which, after observing the individual blocks and their assembled shape, quickly plans and executes the assembly motion sequence that picks up each block and incrementally build the target shape. A multi stage planner is used to find the suitable assembly solutions, assembly sequences and grip sequences considering various constraints, and re-grasping is used when the block target pose is not directly realizable or the block pose is ambiguous. The suggested system is implemented for a commercial UR5e robotic arm and a novel two degrees of freedom (DOF) gripper capable of in-hand manipulation, which further speeds up the manipulation speed. It was experimentally validated through a public competitive demonstration, where the suggested system completed all assembly tasks reliably with outstanding performance.

An Investigation Into the Compliance of SCARA Robots. Part I: Analytical Model

1988 ◽  
Vol 110 (1) ◽  
pp. 18-22 ◽  
Author(s):  
H. A. ElMaraghy ◽  
B. Johns
Keyword(s):  
Degrees Of Freedom ◽  
Torsional Stiffness ◽  
Force Model ◽  
Robot Arm ◽  
Relative Significance ◽  
End Effector ◽  
Scara Robot ◽  
Revolute Joints ◽  
Tool Axis ◽  
Assembly Tasks

A special class of robots suited for assembly tasks called SCARA (Selective Compliance Assembly Robot Arm) provides a degree of built-in flexibility due to robot structure. In such robots there are three revolute joints and a prismatic joint. They offer four degrees of freedom consisting of rotation about two vertical and parallel axes at the revolute joints, and translation and rotation about the tool axis. Some models offer additional degrees of freedom at the end effector. Structural compliance can arise due to the stiffness of the robot links, drive system, grippers as well as the assembled parts. The largest effect is due to the drive torsional stiffness followed by the grippers, workpieces and the robot tool link. Knowledge of the inherent flexibility is extremely useful in designing tooling and fixtures, in laying out the assembly work cell according to the amount of compliance available in various regions of the robot work envelope, in guarding against wedging and jamming and in specifying external Remote Centre Compliance devices (RCC) if necessary. In this paper the various sources of compliance built into a SCARA robot system are outlined together with their relative significance. A mathematical model which expresses the end effector deflection as a function of the robot Jacobian and the drive compliance parameters in Cartesian coordinates has been developed. The modified generalized assembly force model developed for the Selective Compliance Assembly Robot Arms (SCARA), used in this investigation, is described. Constraints required to prevent jamming and wedging of parts during assembly are outlined. The application of this compliance model for both rotational and prismatic part insertion is described. The conditions required to obtain true or semi-compliance centres for the SCARA robot end effector are derived and discussed.

Cooperation and Null-Space Control of Networked Omni-Directional Mobile Manipulators

2020 ◽  
Author(s):  
Michael John Chua ◽  
Yen-Chen Liu
Keyword(s):  
Degrees Of Freedom ◽  
Null Space ◽  
Kinematic Model ◽  
Mobile Manipulator ◽  
Main Task ◽  
Mobile Manipulators ◽  
Robot Arm ◽  
Task Space ◽  
End Effector ◽  
Mobile Base

Abstract This paper presents cooperation and null-space control for networked mobile manipulators with high degrees of freedom (DOFs). First, kinematic model and Euler-Lagrange dynamic model of the mobile manipulator, which has an articulated robot arm mounted on a mobile base with omni-directional wheels, have been presented. Then, the dynamic decoupling has been considered so that the task-space and the null-space can be controlled separately to accomplish different missions. The motion of the end-effector is controlled in the task-space, and the force control is implemented to make sure the cooperation of the mobile manipulators, as well as the transportation tasks. Also, the null-space control for the manipulator has been combined into the decoupling control. For the mobile base, it is controlled in the null-space to track the velocity of the end-effector, avoid other agents, avoid the obstacles, and move in a defined range based on the length of the manipulator without affecting the main task. Numerical simulations have been addressed to demonstrate the proposed methods.

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