scholarly journals Multi-Seam Tracking With a Portable Robotic Welding System in Unstructured Environments

2022 ◽  
Author(s):  
Shuangfei Yu ◽  
Yisheng Guan ◽  
Zhi Yang ◽  
Chutian Liu ◽  
Jiacheng Hu ◽  
...  
Keyword(s):  
Forward Direction ◽  
Seam Tracking ◽  
Robotic Welding ◽  
Production Environment ◽  
Welding Torch ◽  
Tracking Process ◽  
Starting Point ◽  
Low Efficiency ◽  
Working Parameters ◽  
Welding System

Abstract Most welding manufacturing of the heavy industry, such as shipbuilding and construction, is carried out in an unstructured workspace. The term Unstructured indicates the production environment is irregular, changeable and without model. In this case, the changeable workpiece position, workpiece shape, environmental background, and environmental illumination should be carefully considered. Because of such complicated characteristics, the welding is currently being relied on the manual operation, resulting in high cost, low efficiency and quality. This work proposes a portable robotic welding system and a novel seam tracking method. Compared to existing methods, it can cope with more complex general spatial curve weld. Firstly, the tracking pose of the robot is modeled by a proposed dual-sequence tracking strategy. On this basis, the working parameters can be adjusted to avoid robot-workpiece collision around the workpiece corners during the tracking process. By associating the forward direction of the welding torch with the viewpoint direction of the camera, it solves the problem that the weld feature points are prone to be lost in the tracking process by conventional methods. Point cloud registration is adopted to globally locate the multi-segment welds in the workpiece, since the system deployment location is not fixed. Various experiments on single or multiple welds under different environmental conditions show that even if the robot is deployed in different positions, it can reach the starting point of the weld smoothly and accurately track along the welds.

Kalman Filtering for Seam Tracking in Master-Slave Robot Remote Welding System

2011 ◽  
Vol 314-316 ◽  
pp. 1005-1008
Author(s):  
Hong Tang Chen ◽  
Hai Chao Li ◽  
Hong Ming Gao ◽  
Lin Wu
Keyword(s):  
Kalman Filtering ◽  
Seam Tracking ◽  
Experimental Results ◽  
Welding Quality ◽  
Welding Seam ◽  
Tracking Process ◽  
Key Factor ◽  
Remote Welding ◽  
Welding System

Welding seam tracking precision is a key factor influencing welding quality for master-slave robot remote welding system. However, it does not satisfy the welding requirement due to significant noises. To eliminate the influence of noises upon the seam tracking precision and improve the seam tracking precision, a master-slave robot remote welding system was built and Kalman filtering (KF) was applied to the seam tracking process. The experimental results show that the KF eliminated the influence of noises upon the seam tracking precision and improved the seam tracking precision.

scholarly journals Mixed Reality-Enhanced Intuitive Teleoperation with Hybrid Virtual Fixtures for Intelligent Robotic Welding

2021 ◽  
Vol 11 (23) ◽  
pp. 11280
Author(s):  
Yun-Peng Su ◽  
Xiao-Qi Chen ◽  
Tony Zhou ◽  
Christopher Pretty ◽  
J. Geoffrey Chase
Keyword(s):  
Haptic Feedback ◽  
Mixed Reality ◽  
Hand Movements ◽  
Robotic Welding ◽  
Virtual Fixtures ◽  
Working Space ◽  
Welding Operation ◽  
Welding Torch ◽  
Operating Space ◽  
Welding System

This paper presents an integrated scheme based on a mixed reality (MR) and haptic feedback approach for intuitive and immersive teleoperation of robotic welding systems. By incorporating MR technology, the user is fully immersed in a virtual operating space augmented by real-time visual feedback from the robot working space. The proposed robotic tele-welding system features imitative motion mapping from the user’s hand movements to the welding robot motions, and it enables the spatial velocity-based control of the robot tool center point (TCP). The proposed mixed reality virtual fixture (MRVF) integration approach implements hybrid haptic constraints to guide the operator’s hand movements following the conical guidance to effectively align the welding torch for welding and constrain the welding operation within a collision-free area. Onsite welding and tele-welding experiments identify the operational differences between professional and unskilled welders and demonstrate the effectiveness of the proposed MRVF tele-welding framework for novice welders. The MRVF-integrated visual/haptic tele-welding scheme reduced the torch alignment times by 56% and 60% compared to the MRnoVF and baseline cases, with minimized cognitive workload and optimal usability. The MRVF scheme effectively stabilized welders’ hand movements and eliminated undesirable collisions while generating smooth welds.

Intelligent seam tracking using ultrasonic sensors for robotic welding

Robotica ◽  
1997 ◽  
Vol 15 (3) ◽  
pp. 275-281 ◽  
Author(s):  
Ajay Mahajan ◽  
Fernando Figueroa
Keyword(s):  
Tracking System ◽  
Welding Process ◽  
Seam Tracking ◽  
Robotic Welding ◽  
Ultrasonic Sensors ◽  
Intelligent Sensor ◽  
Novel Approach ◽  
Transmitted Waves ◽  
Welding Torch ◽  
Arc Welding Process

This paper presents a novel approach for seam tracking using ultrasonics. An ultrasonic seam tracking system has been developed for robotic welding which tracks a seam that curves freely on a two-dimensional surface. The seam is detected by scanning the area ahead of the torch and monitoring the amplitude of the waves received after reflection from the workpiece surface. Scanning is accomplished by using two ultrasonic sensors (a transmitter and a receiver) mounted on a stepper motor such that the transmitter angle is the same as the receiver angle. The motor is mounted on the end-effector just ahead of the welding torch and covers a ninety degree arc in front of the torch. If there is no seam then the receiver receives most of the transmitted waves after reflection, but if there is a seam then most of the transmitted waves are dispersed in directions other than that of the receiver. The system has been tested and is very robust in the harsh environments generated by the arc welding process. The robustness of the system stems from using various schemes such as time windowing, a waveguide, air and metal shields, and an intelligent sensor manager. This ultrasonic system offers some distinct advantages over traditional systems using vision and other sensing techniques. It can be used to weld very shiny surfaces, and is a very economical method in terms of cost as well as computational intensity. The system can be used to detect seams less than 0.5 mm wide and 0.5 mm deep.

Semiadaptive Synergic-Fill Welding Tractor for Ship Unit Erection

2003 ◽  
Vol 19 (03) ◽  
pp. 151-158
Author(s):  
D. Harwig ◽  
B. Zheng ◽  
C. Reichert ◽  
T. Huang ◽  
A. Joseph ◽  
...  
Keyword(s):  
Control Algorithm ◽  
Weld Bead ◽  
Seam Tracking ◽  
Welding Parameters ◽  
Bead Size ◽  
Welding Torch ◽  
Starting Point ◽  
Flux Cored Arc Welding ◽  
Joint Width ◽  
Weld Bead Size

At most U.S. shipyards, the bottleneck for improving productivity is unit fabrication and ship erection. Fit-up during unit, super-unit, and ship erection is difficult, resulting in variable gap and mismatch, which promote defects and repair. A semiadaptive synergic-fill welding tractor was developed for improving the productivity of seam welds during erection. The tractor has many features that advanced robots have but is simple to use because it relies on operator pass planning instead of robotic path preplanning. The "synergic-fill" welding concept was developed to maximize the deployment of robust welding procedures. This was a new control process for making changes to weld bead size during fabrication using one knob. The synergic-fill welding concept was developed for flux-cored arc welding of DH36 steels for horizontal erection seams. These seams have a range of gap and require a range of weld bead sizes to uniformly fill the weld seam. Welding parameters that ensured a constant base metal dilution were optimized and programmed into the synergic control. In addition, the welding tractor was developed with a laser seam tracking vision sensor and adaptive-fill control. The new control allows the operator to intervene during welding and toggle the adaptive features on and off. A special four-axis tractor was developed to permit cross-seam and torch height control for seam tracking while oscillating the welding torch. The laser sensor was integrated with modular fixturing to permit welding with either angled or transverse oscillation. The adaptive control algorithm varied the weld size from the synergic-fill starting point that was selected by the operator. The weld bead was made proportionally larger or smaller as the joint width became larger or smaller within the process capability range. A semiadaptive control algorithm was developed for the horizontal welding application. The process was not completely automatic. The operator, who plans the position of the welding torch for each weld bead in a layer, applies the process. Further, he made weld bead size decisions based on the joint width. Once the welding system was started, it tracked the bead location as the groove width changed, controlled the torch height, and can adaptively vary bead size relative to joint width. This flexible technology will minimize the susceptibility to defects during erection welding.

Seam tracking of large pipe structures for an agile robotic welding system mounted on scaffold structures

2018 ◽  
Vol 50 ◽  
pp. 242-255 ◽  
Author(s):  
Xiaohan Chen ◽  
Audelia Gumarus Dharmawan ◽  
Shaohui Foong ◽  
Gim Song Soh
Keyword(s):  
Seam Tracking ◽  
Robotic Welding ◽  
Welding System

Visual Robotic Welding System

2016 ◽  
Vol 85 (7) ◽  
pp. 657-662
Author(s):  
Satoshi YAMANE
Keyword(s):  
Robotic Welding ◽  
Welding System

Developing a Kinematic Estimation Model for a Climbing Mobile Robotic Welding System

2010 ◽  
Author(s):  
Aaron T. O’Toole ◽  
Stephen L. Canfield
Keyword(s):  
Kinematic Model ◽  
Robotic Welding ◽  
Estimation Model ◽  
Mobile Platforms ◽  
Low Profile ◽  
Turning Radius ◽  
Equivalence Model ◽  
Kinematic Equivalence ◽  
Welding System ◽  
Robot Platform

Skid steer tracked-based robots are popular due to their mechanical simplicity, zero-turning radius and greater traction. This architecture also has several advantages when employed by mobile platforms designed to climb and navigate ferrous surfaces, such as increased magnet density and low profile (center of gravity). However, creating a kinematic model for localization and motion control of this architecture is complicated due to the fact that tracks necessarily slip and do not roll. Such a model could be based on a heuristic representation, an experimentally-based characterization or a probabilistic form. This paper will extend an experimentally-based kinematic equivalence model to a climbing, track-based robot platform. The model will be adapted to account for the unique mobility characteristics associated with climbing. The accuracy of the model will be evaluated in several representative tasks. Application of this model to a climbing mobile robotic welding system (MRWS) is presented.

scholarly journals Influence of Selected Model Parameters on the Electromagnetic Levitation Melting Efficiency

2021 ◽  
Vol 11 (9) ◽  
pp. 3827
Author(s):  
Blazej Nycz ◽  
Lukasz Malinski ◽  
Roman Przylucki
Keyword(s):  
Electromagnetic Levitation ◽  
Optimization Methods ◽  
Calculation Model ◽  
Model Parameters ◽  
Starting Point ◽  
Low Efficiency ◽  
The Relationship ◽  
Reactive Metals ◽  
Electromagnetic Levitation Melting ◽  
Metal Melting

The article presents the results of multivariate calculations for the levitation metal melting system. The research had two main goals. The first goal of the multivariate calculations was to find the relationship between the basic electrical and geometric parameters of the selected calculation model and the maximum electromagnetic buoyancy force and the maximum power dissipated in the charge. The second goal was to find quasi-optimal conditions for levitation. The choice of the model with the highest melting efficiency is very important because electromagnetic levitation is essentially a low-efficiency process. Despite the low efficiency of this method, it is worth dealing with it because is one of the few methods that allow melting and obtaining alloys of refractory reactive metals. The research was limited to the analysis of the electromagnetic field modeled three-dimensionally. From among of 245 variants considered in the article, the most promising one was selected characterized by the highest efficiency. This variant will be a starting point for further work with the use of optimization methods.

Study and Implement on Key Technologies of Ship-Welding Mobile Robot

2010 ◽  
Vol 44-47 ◽  
pp. 321-325
Author(s):  
Liang Hua ◽  
Lin Lin Lv ◽  
Ju Ping Gu ◽  
Yu Jian Qiang
Keyword(s):  
Mobile Robot ◽  
Control Method ◽  
Structure Design ◽  
Seam Tracking ◽  
Precision Positioning ◽  
Positioning Control ◽  
Controlling System ◽  
Welding Torch ◽  
Driven System ◽  
And Control

The key technilogies of ship-welding mobile robot applied to ship-building in plane block production line were researched and realized. The mechanical structure design of the robot was completed. The motion-controlling system of of two-wheel differential driving mobile robot was developed. A novel precision positioning control method of welding torch using ultrasonic motors was putforward. The mechanism and control-driven system of precision positioning system for welding torch were completed. The platform of obstacle avoidance navigation system was designed and the strategies of seam tracking, trajectory and posture adjustment were preliminary studied. The methods and results put forward in the paper could act as the base of deep research on the theories and technologies of ship-welding mobile robot.

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