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Article
Publication date: 28 December 2017

Jian-jun Yuan, Shuai Wang, Weiwei Wan, Yanxue Liang, Luo Yang and Yifan Liu

The aim of this paper is to implement direct teaching of industrial manipulators using current sensors. The traditional way to implement teaching is either to use a teaching…

Abstract

Purpose

The aim of this paper is to implement direct teaching of industrial manipulators using current sensors. The traditional way to implement teaching is either to use a teaching pedant, which is time consuming, or use force sensors, which increases system cost. To overcome these disadvantages, a novel method is explored in the paper by using current sensors installed at joints as torque observers.

Design/methodology/approach

The method uses current sensors installed at each joint of a manipulator as torque observers and estimates external forces from differences between joint-driven torque computed based on the values of current sensors and commanded values of motor-driven torque. The joint-driven torque is computed by cancelling out both pre-calibrated gravity and friction resistance (compensation). Also, to make the method robust, the paper presents a strategy to detect unexpected slowly drifts and zero external forces and stop the robot in those situations.

Findings

Experimental results demonstrated that compensating the joint torques using both pre-calibrated gravity and friction resistance has performance comparable to a force sensor installed on the end effector of a manipulator. It is possible to implement satisfying direct teaching without using force sensors on 7 degree of freedom manipulators with large mass and friction resistance.

Originality/value

The main contribution of the paper is that the authors cancel out both pre-calibrated gravity and friction resistance to improve the direct teaching using only current sensors; they develop methods to avoid unsafe situations like slow drifts. The method will benefit industrial manipulators, especially those with large mass and friction resistance, to realize flexible and reliable direct teaching.

Details

Assembly Automation, vol. 38 no. 2
Type: Research Article
ISSN: 0144-5154

Keywords

Article
Publication date: 3 April 2007

Mark Lowe, Elizabeth Hood and Mike Ozog

This technical paper aims to provide an overview of thin‐film force sensors, present discussions of various ways these force sensors are used in automated systems, and offer…

Abstract

Purpose

This technical paper aims to provide an overview of thin‐film force sensors, present discussions of various ways these force sensors are used in automated systems, and offer possibilities for future adaptations. Areas of interest are medicine, industry, and consumer products.

Design/methodology/approach

Current uses of thin‐film force sensors are presented based on existing prototypes and research. Current research serves as a springboard to identifying ideas for future research and development.

Findings

Regarding thin‐film force sensors, finds that, thanks to features of current force‐sensing technology, consumers can expect continued introduction of high‐quality and very realistic “feeling” systems.

Originality/value

Presents novel uses of force sensors and explores ideas for future research.

Details

Sensor Review, vol. 27 no. 2
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 21 September 2015

Mojtaba Ghodsi, Shahed Mirzamohamadi, Soheil Talebian, Yousef Hojjat, Mohammadmorad Sheikhi, Amur Al-Yahmedi and Abdullah Özer

– This paper aims to investigate a novel giant magnetostrictive (GM) force sensor using Terfenol-D rod.

Abstract

Purpose

This paper aims to investigate a novel giant magnetostrictive (GM) force sensor using Terfenol-D rod.

Design/methodology/approach

First of all, principle of GM force sensor based on positive magnetostriction of Terfenol-D is presented. Then, design procedure of the GM force sensor is stated. Magnetic properties such as B-H curve and permeability of Terfenol-D are measured by a novel experimental setup and the results are used in analytical model, sensitivity estimation and numerical simulations. Then, an analytical model is presented and a numerical simulation using CST Studio Suite 2011 software is done. So as a result of numerical simulations, optimum geometry of the GM force sensor is obtained related to the condition in which the GM force sensor has highest sensitivity. After that, the sensor is fabricated using the simulation results and is tested by means of an experimental setup. Characteristic curve of the GM force sensor in several conditions is measured and the optimum operational condition is obtained considering highest sensitivity condition of the sensor. Also operational diagrams of the GM force sensor is plotted in loading and unloading conditions. Characteristics of the GM force sensor in optimum condition are presented.

Findings

It was found that the GM force sensor has maximum sensitivity and maximum linearity in 0.8A current, which can be known as optimum condition of application. In this sensor, maximum sensitivity is 0.51 mV/N (while current is 0.8A), which is highest among older investigations.

Originality/value

At last, theoretical, numerical and experimental results are compared and the criteria for magnetostrictive sensor design are presented.

Details

Sensor Review, vol. 35 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 21 March 2016

Drew van der Riet, Riaan Stopforth, Glen Bright and Olaf Diegel

This paper aims to explore the electronic design of the Touch Hand: a low-cost electrically powered prosthetic hand. The hand is equipped with an array of sensors allowing for…

Abstract

Purpose

This paper aims to explore the electronic design of the Touch Hand: a low-cost electrically powered prosthetic hand. The hand is equipped with an array of sensors allowing for position control and haptic sensation. Pressure sensors are used on the fingertips to detect grip force. A temperature sensor placed in the fingertip is used to measure the contact temperature of objects. Investigations are made into the use of cantilever vibration sensors to detect surface texture and object slippage. The hand is capable of performing a lateral grip of 3.7 N, a power grip of 19.5 N and to passively hold a weight of up to 8 kg with a hook grip. The hand is also tested on an amputee and used to perform basic tasks. The amputee took 30 min to learn how to operate the hands basic gripping functions.

Design/methodology/approach

Problems of previous prosthetic hands were investigated, followed by ways to improve or have similar capabilities, yet keeping in mind to reduce the price. The hand was then designed, simulated, developed and then tested. The hand was then displayed to public and tested with an amputee.

Findings

The Touch Hand’s capabilities with the usage of the low-cost materials, components and sensory system was obtained in the tests that were conducted. The results are shown in this paper to identify the appropriateness of the sensors for a usage while the costs are reduced. Furthermore, models were developed from the results obtained to take into account factors such as the non-slip material.

Research limitations/implications

The research was restricted to a US$1,000 budget to allow the availability of a low-cost prosthetic hand.

Practical implications

The Touch Hand had to have the ability to supply the amputee with haptic feedback while allowing the basic grasping of objects. The commercial value is the availability of an affordable prosthetic hand that can be used by amputees in Africa and other Lower-Income countries, yet allowing a more advanced control system compared to the pure mechanical systems currently available.

Social implications

The Touch Hand has the ability to give amputees affected in war situations the ability to grasp objects in a more affordable manner compared to the current available options. Feedback from amputees about the current features of the Touch Hand was very positive and it proves to be a way to improve society in Lower-Income countries in the near future. A sponsorship program is being developed to assist amputees with the costs of the Touch Hand.

Originality/value

The contributions of this research is a low-cost prototype system than can be commercialized to allow amputees in the Lower-Income countries to have the ability of a prosthetic hand. A sensory system in the hand is also explained which other low-cost prosthetic hands do not have, which includes temperature, force and vibration. Models of the sensors used that are developed and calibrated to the design of the hand are also described.

Details

Sensor Review, vol. 36 no. 2
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 21 September 2015

Alireza Hassanbeiglou, Masoud Kalantari, Elaheh Mozaffari, Javad Dargahi and József Kövecses

The purpose of this paper is to introduce a new tactile array sensor into the medical field to enhance current robotic minimally invasive surgery (RMIS) procedures that are still…

Abstract

Purpose

The purpose of this paper is to introduce a new tactile array sensor into the medical field to enhance current robotic minimally invasive surgery (RMIS) procedures that are still limited in scope and versatility. In this paper, a novel idea is proposed in which a tactile sensor array can measure rate of displacement in addition to force and displacement of any viscoelastic material during the course of a single touch. To verify this new array sensor, several experiments were conducted on a diversity of tissues from which it was concluded that this newly developed sensory offers definite and significant enhancements.

Design/methodology/approach

The proposed array sensor is capable of extracting force, displacement and displacement rate in the course of a single touch on tissues. Several experiments have been conducted on different tissues and the array sensor to verify the concept and to verify the output of the sensor.

Findings

It is shown that this new generation of sensors are required to distinguish the difference in hardness degrees of materials with viscoelastic behavior.

Originality/value

In this paper, a new generation of tactile sensors is proposed that is capable of measuring indentation time in addition to force and displacement. This idea is completely unique and has not been submitted to any conference or journal.

Details

Sensor Review, vol. 35 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 4 February 2020

Dong Tang, Li Wang, Yang Liu, Ning Liu, Yuzhe Wu and Lie Chen

This paper aims to design and optimize the threaded fastener of leakage current particulate matter (PM) sensor. The corresponding air-tight test is conducted to ensure the…

Abstract

Purpose

This paper aims to design and optimize the threaded fastener of leakage current particulate matter (PM) sensor. The corresponding air-tight test is conducted to ensure the reliability of the installation strategy with screw connection.

Design/methodology/approach

Research on the pressure-deformation curve of seal gasket was conducted and the vibration load of engine was considered for the calculation of the minimum installation pre-tightening force. Simultaneously, the danger threaded section area was calculated, and the carrying capacity was verified. The height of the welding line was studied to ensure the reliability of the application. FEA was carried out to acquire the relationship between local structure size and local stress for continuous improvement of thread connection. The installation torque range was acquired from the torque control principle for the pre-tightening force. The sealing reliability of the connector was proved with leakage.

Findings

The air tightness of the thread connector is proved to be fine. When the pre-tightening force is over 8,000 N, and its length reaches 2 mm, the connector has good reliability at ambient temperature. The tightening torque of 60-74 Nm can guarantee the reliable fixing ability of thread connector, and its plastic non-deformation ability in the process of repeated tearing down.

Originality/value

This paper provides an installation strategy and an optimization of PM sensor, which has a positive effect on the study and the manufacture of PM sensor. It is helpful to further develop PM sensor and after-treatment technology. This kind of real-time monitoring PM sensor needs to be studied further to achieve its commercial application.

Details

Sensor Review, vol. 40 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 16 January 2017

Chengzhu Xiu, Liang Ren, Hongnan Li and Ziguang Jia

Magnetic permeability variations of ferromagnetic materials under elastic stress offer the potential to monitor tension based on the inverse magnetostrictive effect. The purpose…

Abstract

Purpose

Magnetic permeability variations of ferromagnetic materials under elastic stress offer the potential to monitor tension based on the inverse magnetostrictive effect. The purpose of this paper is to propose an innovative self-inductance tension eddy current sensor to detect tension.

Design/methodology/approach

The effectiveness of conventional elasto-magnetic (EM) sensor is limited during signal detection, due to its complex sensor structure, which includes excitation and induction coils. In this paper, a novel self-inductance tension eddy current sensor using a single coil is presented.

Findings

The output signal was analyzed through oscilloscope in the frequency domain and via self-developed data logger in the time domain. Experimental results show the existence of a linear relationship between voltage across the sensor and tension. The sensor sensitivity is dependent on operating conditions, such as current and frequency of the input signal.

Practical implications

The self-inductance sensor has great potential for replacing conventional EM sensor due to its low cost, simple structure, high precision and good repeatability in tension detection.

Originality/value

A spilt sleeve structure provides a higher permeability path to magnetic field lines than a non-sleeve structure, thus reducing the loss of magnetic field. The self-developed data logger improves sensitivity and signal-to-noise ratio of sensor. The novel sensor, as a replacement of the EM sensor, can easily and accurately monitor the tension force.

Details

Sensor Review, vol. 37 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 3 September 2020

Chenggang Li, Weishan Song and Yong Song

Six-axis force sensors play an important role in civilian and military fields because of their multifunctionality. In the context of sensor structure design, sensitivity and

Abstract

Purpose

Six-axis force sensors play an important role in civilian and military fields because of their multifunctionality. In the context of sensor structure design, sensitivity and sensitivity isotropy are often considered. This paper aims to study the possible relationship between the sensitivity/sensitivity isotropy and structural parameters of an 8/4–4 parallel six-axis force sensor. A comprehensive evaluation index and structural optimization design scheme are suggested in the end.

Design/methodology/approach

Based on the conditional number of the Jacobian matrix spectral norm, the sensitivity and sensitivity isotropy of the sensor are derived. Orthogonal experiments are used to determine the degree of primary and secondary factors that have a substantial effect on the sensor characteristics. The relationship between the performance indices and the structural parameters is analyzed by the performance atlas method. The comprehensive evaluation index lays the foundation for the structural optimization design of an 8/4–4 parallel six-axis force sensor.

Findings

The variation in each performance index of the sensor for each of the structural parameters is analyzed, and the structural parameters of the sensor with the desired performance indices can be easily selected from the performance atlases. A comprehensive performance evaluation index with a target value of 1 is proposed, and the overall influence of the structural parameters on the sensor performance index is investigated. A simulation example shows the feasibility of the proposed evaluation index.

Originality/value

The importance of each structural parameter of the 8/4–4 parallel six-axis force sensor is determined through orthogonal experiments in this paper. Relations among the structural parameters meeting the performance indices are derived and shown in the performance atlases. A comprehensive evaluation index is proposed to analyze the overall sensor performance.

Details

Sensor Review, vol. 40 no. 5
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 7 September 2012

Xuefeng Zhang, Yulong Zhao and Xuelei Zhang

The purpose of this paper is to provide a thin tactile force sensor array based on conductive rubber and to offer descriptions of the sensor design, fabrication and test.

Abstract

Purpose

The purpose of this paper is to provide a thin tactile force sensor array based on conductive rubber and to offer descriptions of the sensor design, fabrication and test.

Design/methodology/approach

The sensor array consists of a sandwich structure. Sensing elements are distributed discretely in the sensor. Each sensing element has two electrodes and a piece of conductive rubber with piezoresistive property. The electrodes, as well as the conductive trace for signal transmission, are printed on the substrate layer by the screen printing technique. A scanning circuit based on zero potential method and an experimental set‐up based on balance to characterize the sensor array are designed and implemented in the test of the sensor array.

Findings

Experimental results verify the validity of the sensor array in measuring the vertical tactile force between the sensing elements and the object.

Research limitations/implications

In this paper, all the sensors are tested without calibration procedures and the procedure of the dynamic test is implemented by manual operation.

Practical implications

The sensor array could be applied to measure the plantar force for gait detection in clinical applications.

Originality/value

The paper presents a tactile force sensor array with discrete sensing elements to essentially restrict the cross‐talk among sensing elements. This paper will provide many practical details that can help others in the field.

Details

Sensor Review, vol. 32 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 1 April 1982

John M. Vranish, Eugene Mitchell and Robert DeMoyer

The US Naval Surface Weapons Center has made good progress in exploiting recent advances in magnetoelastic materials technologies and has designed magnetic circuits which are…

Abstract

The US Naval Surface Weapons Center has made good progress in exploiting recent advances in magnetoelastic materials technologies and has designed magnetic circuits which are easily adapted to force feedback sensors. Preliminary designs have been completed for grip and torque sensor modules for an industrial robot.

Details

Sensor Review, vol. 2 no. 4
Type: Research Article
ISSN: 0260-2288

1 – 10 of over 6000