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1 – 10 of 495Helder Carvalho, Luís F. Silva, Ana Rocha and João Monteiro
The purpose of this paper is to develop and test control methods for real‐time automatic presser‐foot force control in industrial sewing machines. In this work, a closed‐loop…
Abstract
Purpose
The purpose of this paper is to develop and test control methods for real‐time automatic presser‐foot force control in industrial sewing machines. In this work, a closed‐loop controller that controls presser‐foot maximum vertical displacement is presented and compared to existing solutions that adjust force depending on sewing speed. Automatic force control can reduce problems such as stitch irregularity, stitch distortions and material damage, besides making material handling easier.
Design/methodology/approach
An electromagnetic force actuator was integrated in an industrial lockstitch machine. A computer‐based control system was designed implementing either speed‐variable force control, closed‐loop control, or emulating a traditional constant‐force system. Maximum presser‐foot displacement values were measured and analysed in relevant sewing situations, and seam quality was assessed.
Findings
Constant‐force control does not allow optimal force setting at all speeds. Speed‐variable force control is an improvement, but requires empirical setting of the speed‐force relation, not always assuring optimal operation. Closed‐loop control adapts force to the requirement of each sewing situation more precisely. Sewing quality is good and material handling is eased.
Research limitations/implications
The actuator has to be optimised regarding response time and maximum force. Some aspects in the behaviour of the control system and actuator have to be further studied.
Practical implications
The proposed control system enables the automatic setting and adaptation of force to all sewing situations, making material handling easier at low speeds without compromising feeding performance at high speed. The closed‐loop controller may be used as a teach‐in system for speed‐dependent control.
Originality/value
This is the first prototype of a closed‐loop control system for presser‐foot force on a lockstitch sewing machine and the first comparative study of control methods for presser‐foot force control.
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States that manufacturing lines cannot be used for production during commissioning and that it is therefore always the goal to reduce the necessary efforts to a maximum extent…
Abstract
States that manufacturing lines cannot be used for production during commissioning and that it is therefore always the goal to reduce the necessary efforts to a maximum extent. Starts with a description of the state‐of‐the‐art in this field based on the situation in the automotive industry. Additionally lists RTD fields to overcome these problems. Goes on to present methods and software tools aiming at a tremendous decrease in efforts required today.
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A team of German researchers have developed sensor‐programmable tools to improve teach‐in programming. These sensor‐tools allow automatic positioning and tracking by the robot.
Zengxi Pan and Hui Zhang
This paper aims to present the critical issues and methodologies to improve robotic machining performance with flexile industrial robots.
Abstract
Purpose
This paper aims to present the critical issues and methodologies to improve robotic machining performance with flexile industrial robots.
Design/methodology/approach
A complete solution using active force control is introduced to address various issues during the robotic machining process.
Findings
Programming complex couture parts without a CAD model is made easy by using force control functions such as lead‐through and path‐learning. The problem of process control is treated with a novel methodology that consists of stiffness modeling, real‐time deformation compensation for quality and controlled material removal rate for process efficiency.
Originality/value
Experimental results showed that higher productivity as well as better surface quality can be achieved, indicating a promising and practical use of industrial robots for machining applications that is not available at present.
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Trygve Thomessen and Terje K. Lien
Presents a robot control system dedicated for grinding and deburring robots. The control system is based on an active force feedback system using three axes force sensor attached…
Abstract
Presents a robot control system dedicated for grinding and deburring robots. The control system is based on an active force feedback system using three axes force sensor attached to the robot’s end effector. This system offers new functionality in rapid programming of the robot by applying automatic programming and force supervision. The system is implemented and tested experimentally on a MultiCraft 560 robot with parallel kinematics. The experimental results show a significant reduction in the programming and set up time compared to conventional robot control systems.
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Abstract
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New trends in flexible automation require new characteristics for robot controllers, the new generation of which are supporting the integration of robots into automated…
Abstract
New trends in flexible automation require new characteristics for robot controllers, the new generation of which are supporting the integration of robots into automated manufacturing environments.
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The purpose of this paper is to propose an approach to managing complexity in postgraduate teaching by increasing the variety of educational provisions and creating opportunities…
Abstract
Purpose
The purpose of this paper is to propose an approach to managing complexity in postgraduate teaching by increasing the variety of educational provisions and creating opportunities for individualisation of learning.
Design/methodology/approach
This case study examines an approach to course design and delivery based on the attenuation‐amplification metaphor of resolving complexity.
Findings
The results of the study suggest that a balanced approach to managing complexity can be effective is helping students develop their personal learning path through the course, making postgraduate study more relevant and meaningful.
Originality/value
This approach offers an alternative to the reductionist approach in dealing with complexity in the tertiary study context.
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