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Article
Publication date: 24 February 2012

Helder 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.

Book part
Publication date: 23 March 2017

Barbara de Lima Voss, David Bernard Carter and Bruno Meirelles Salotti

We present a critical literature review debating Brazilian research on social and environmental accounting (SEA). The aim of this study is to understand the role of politics in…

Abstract

We present a critical literature review debating Brazilian research on social and environmental accounting (SEA). The aim of this study is to understand the role of politics in the construction of hegemonies in SEA research in Brazil. In particular, we examine the role of hegemony in relation to the co-option of SEA literature and sustainability in the Brazilian context by the logic of development for economic growth in emerging economies. The methodological approach adopts a post-structural perspective that reflects Laclau and Mouffe’s discourse theory. The study employs a hermeneutical, rhetorical approach to understand and classify 352 Brazilian research articles on SEA. We employ Brown and Fraser’s (2006) categorizations of SEA literature to help in our analysis: the business case, the stakeholder–accountability approach, and the critical case. We argue that the business case is prominent in Brazilian studies. Second-stage analysis suggests that the major themes under discussion include measurement, consulting, and descriptive approach. We argue that these themes illustrate the degree of influence of the hegemonic politics relevant to emerging economics, as these themes predominantly concern economic growth and a capitalist context. This paper discusses trends and practices in the Brazilian literature on SEA and argues that the focus means that SEA avoids critical debates of the role of capitalist logics in an emerging economy concerning sustainability. We urge the Brazilian academy to understand the implications of its reifying agenda and engage, counter-hegemonically, in a social and political agenda beyond the hegemonic support of a particular set of capitalist interests.

Details

Advances in Environmental Accounting & Management: Social and Environmental Accounting in Brazil
Type: Book
ISBN: 978-1-78635-376-4

Keywords

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