Flexible knitted sensing device for identifying knee joint motion patterns

Li, Yutian; Miao, Xuhong; Raji, Rafiu King

doi:10.1088/1361-665x/ab4afe

Cited by 22 publications

(27 citation statements)

References 36 publications

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“…When M = 4, the intercept and slope values of CR st (4_N) become faintly higher than those of CR st (4_N) ; 5. When M ⩾ 5, the intercept values of CR st (M_N) keep slightly smaller than those of NCR st (M_N) , while the slope values of CR st (M_N) remain slightly higher than those of NCR st (M_N) which also can be deduced by equations (8)- (9).…”

Section: Relationship Between the Equivalent Resistance And Nmentioning

confidence: 57%

“…Finally, to compare the two established models, threedimensional surface plots of the calculated resistances, NCR st (M_N) and CR st (M_N) , were made according to equations (8)- (9). Here M is from 7 to 500, and N is from 1 to 500, as displayed in Figure 14 containing the projections on the coordinate planes (Figure 14 NCR st (M_N) becomes slightly small as the increase of M where the resistance value approaches zero.…”

Section: Comparison Of the Two Established Resistive Network Modelsmentioning

confidence: 99%

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Resistive network model of the weft-knitted strain sensor with the plating stitch-Part 1: Resistive network model under static relaxation

Zhang

Long

2020

Journal of Engineered Fibers and Fabrics

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The resistive network model of the weft-knitted strain sensor with the plating stitch under static relaxation is studied based on the knitted loop structure and circuit principle. The prepared sensors are divided into the sensing area and the non-sensing area. The former consists of the conductive face yarn and the insulated elastic ground yarn, while the latter includes the normal face yarn and the same ground yarn. The loop of conductive face yarn not only produces length-related resistance but also causes the jamming contact resistances along the width and length direction. Besides, the elastic ground yarn has a potential impact on the contact situation of the conductive face yarn at the interlocking point, determining whether the interlocking contact resistance exists. Therefore, two resistive network models have been established accordingly. In addition to the length-related resistance, the first model focused on both the jamming and interlocking contact resistances, while the second one only dealt with the jamming contact resistance. In the case of applying voltage along the two ends of the course, the theoretical calculations of the corresponding network models were performed using a series of equivalent transformations. Finally, the correctness and usability of the two models were verified through experiments and model calculations. It was found that both models can predict that the equivalent resistance increases with the conductive wale number and decreases with the conductive course number. It was implied that the first model’s calculating resistances are closer to the experimental data and lower than those of the second model. The difference in the calculating resistances of the two models would become smaller as the course number increases. Thus, the investigation indicates that the jamming contact resistance has a more considerable influence on the resistive network than the interlocking contact resistance.

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Section: Relationship Between the Equivalent Resistance And Nmentioning

confidence: 57%

Section: Comparison Of the Two Established Resistive Network Modelsmentioning

confidence: 99%

Resistive network model of the weft-knitted strain sensor with the plating stitch-Part 1: Resistive network model under static relaxation

Zhang

Long

2020

Journal of Engineered Fibers and Fabrics

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“…From the use of warp knit to create textile antennas to the use of weft knit to create strain sensors, the application of knitting to create conventional electronics is being rapidly adopted [ 1 , 2 , 3 , 4 , 5 , 6 ]. In particular, conductive weft knitted fabrics have been utilised as strain sensors, because of their elastic structure and piezoresistivity [ 7 , 8 , 9 , 10 , 11 ]. The piezoresistivity of the sensor is the behaviour of the sensor’s electrical resistance when load is applied or the sensor is extended.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Miss and Tuck Stitches on a Weft Knit Strain Sensor

Ayodele

Zaidi

Scott

et al. 2021

Sensors

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Weft knitted conductive fabrics can act as excellent textile strain sensors for human motion capture. The loop architecture dictates the overall electrical properties of weft knit strain sensors. Therefore, research into loop architecture is relevant for comprehensively investigating the design space of e-textile sensors. There are three main types of knit stitches, Knitted loop stitch, Miss stitch, and Tuck stitch. Nevertheless, most of the research into weft knit strain sensors has largely focused on fabrics with only knitted loop stitches. Miss and tuck stitches will affect the contact points in the sensor and, consequently, its piezoresistivity. Therefore, this paper investigates the impact of incorporating miss and tuck stitches on the piezoresistivity of a weft knit sensor. Particularly, the electromechanical models of a miss stitch and a tuck stitch in a weft knit sensor are proposed. These models were used in order to develop loop configurations of sensors that consist of various percentages of miss or tuck stitches. Subsequently, the developed loop configurations were simulated while using LTspice and MATLAB software; and, verified experimentally through a tensile test. The experimental results closely agree with the simulated results. Furthermore, the results reveal that increases in the percentage of tuck or miss stitches in weft knit sensor decrease the initial and average resistance of the sensor. In addition, it was observed that, although the piezoresistivity of a sensor with tuck or miss stitches is best characterised as a quadratic polynomial, increases in the percentage of tuck stitches in the sensor increase the linearity of the sensor’s piezoresistivity.

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“…In the above surveys, the resistances involved are divided into contact resistance generated by the interlocking of the conductive yarns and length-related resistance. In practical applications, the weft plating technology is often adopted 1,2,4,6,8,[11][12][13]22 to increase the repeatability and stability of the sensor. The conductive yarn is used as the face yarn and the insulated elastic yarn used as the ground yarn in the sensing area.…”

Section: Introductionmentioning

confidence: 99%

Resistive network model of the weft-knitted strain sensor with the plating stitch-Part 2: Resistive network model during the elongation along course direction

Zhang

Long

2020

Journal of Engineered Fibers and Fabrics

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Based on the static resistive network investigated in Part 1 of this series, the resistive network model of the weft-knitted strain sensor with the plating stitch is explored under the elongation along course direction, and it changes with the conductive loops’ configuration and contact situation. Since the voltage is applied at both ends of the course, under a specific stretching state, the resistive network model can be reduced to a resistance network connected in series in the course direction and parallel in the wale direction, which determines that the sensor’s equivalent resistance increases with the growth of the conductive wale number, and decreases with the raise of the conductive course number. Through experiment and model calculation, it can be obtained that in the initial stage of stretching, the contact resistances’ changes are the main factors affecting the mechanical–electrical performance of the sensor. Then as the sensor is further stretched, the length-related resistances of the conductive yarn segments begin to affect the sensor’s properties due to yarns’ slippage and self-elongation. In addition, the weft jacquard plating technology makes the strain of the sensor reach about 32% before yarns’ slippage and self-elongation, which expands the sensor’s measurable strain range, and avoids irreversible deformation of the sensor after repeated use in this range. It can be verified that the sensor’s gauge factor can be improved by reducing the conductive course number and increasing the conductive wale number. It should be noted that the ground yarn will reduce the gauge factor of the sensor during stretching, so it is necessary to choose a ground yarn with a smaller fineness than the conductive face yarn and good elasticity in practical.

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Flexible knitted sensing device for identifying knee joint motion patterns

Cited by 22 publications

References 36 publications

Resistive network model of the weft-knitted strain sensor with the plating stitch-Part 1: Resistive network model under static relaxation

Resistive network model of the weft-knitted strain sensor with the plating stitch-Part 1: Resistive network model under static relaxation

The Effect of Miss and Tuck Stitches on a Weft Knit Strain Sensor

Resistive network model of the weft-knitted strain sensor with the plating stitch-Part 2: Resistive network model during the elongation along course direction

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