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1

A two dimensional approach for modelling of pennate muscle behaviour

Wojnicz W., Zagrodny B., Ludwicki M., Awrejcewicz J., Wittbrodt E.

Biocybernetics and Biomedical Engineering

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2017

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Vol. 37, no. 2

302--315

EN

The purpose of this study was to elaborate a two-dimensional approach for unipennate and bipennate striated skeletal muscle modelling. Behavior of chosen flat pennate muscle is modelled as a rheological system composed of serially linked passive and active fragments having different mechanical properties. Each fragment is composed of three elements: mass element, elastic element and viscous element. Each active fragment furthermore contains the contractile element. Proposed approach takes into consideration that muscle force depends on a planar arrangement of muscle fibers. Paper presents results of numerical simulations, conclusions deduced on the base of these results and a concept of experimental verification of proposed models.

2

Influence of additional loads on chosen gait parameters and muscles activity

Ludwicki M., Zagrodny B., Wojnicz W., Mrozowski J., Awrejcewicz J.

Vibrations in Physical Systems

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2016

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Vol. 27

227--236

EN

This paper is devoted to human motion analysis and comparison of chosen kinematics parameters during normal gait with and without additional load in a form of backpack. A stability in both cases were compared in both frontal and sagittal planes, by applying a video tracking system. Experimental tests performed on treadmill, passive markers, placed on volunteers bare skin were used. Additionally, an infra-red camera was employed to evaluate muscle activity and its groups involved in the movement. The change of body temperature and distribution of the thermal maps were observed. Analysing these thermograms, loading of different muscle groups was evaluated. During the experiment, an attempt to correlate a results obtained from a thermal imaging camera and video tracking system were made. It is shown that thermal imaging can help to evaluate an asymmetry in muscle load and in some cases can help to detect pathological cases, what was confirmed with motion analysis. Advantages and disadvantages of this method were also described.

3

Infractometric measurement of sucrose concentration

Brzeziński S., Ludwicki M.

Biotechnology and Food Science

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2014

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Vol. 78, nr 2

141--145

EN

Application of the infrared spectroscopy method in the measurement of sucrose concentration within the range from 6 to 20% dry matter has been studied. Results obtained showed a linear relationship between sugar concentration and absorbance with correlation coefficient value close to 0.996. The effect of colored substances and invert sugar present in the measured solutions on results of the measurements has been also analyzed.

4

On the human arm motion camera tracking system

Andrysiak T., Awrejcewicz J., Ludwicki M., Zagrodny B.

Vibrations in Physical Systems

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2012

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Vol. 25

41--46

EN

This paper presents results of research devoted to tracking human arm trajectories in sagittal plane by means of motion capture. One camera tracking system was developed. Co-ordinates of upper limb joints (distincted by light reflecting markers) were obtained via tracking software. Markers were illuminated coaxially to the optical axis of the lens to obtain maximum of reflectivity. Positions, linear velocities and accelerations of a shoulder, elbow, wrist and palm in a sagittal plane were presented. Obtained results in the form of points (in Cartesian co-ordinate system) can be adopted for control of mechanism and robots with kinematics similar to that of a human arm. The obtained results show that in studied biological systems there are no fixed trajectories. All movement co-ordinates (including velocities, accelerations and joints angles) are slightly different for each time selected until movement task is completed. Presented method is relatively inexpensive and noninvasive and can be adopted for other types of motion capture.

5

Modelling, simulation and experimental studies of the axially excited spatial double physical pendulum coupled by universal joints

Awrejcewicz J., Kudra G., Ludwicki M.

Vibrations in Physical Systems

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2012

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Vol. 25

47--52

EN

We are aimed on developing the physical and mathematical model of a novel, spatial, double physical pendulum being coupled by two universal joints. The active part of first joint is axially excited by a non-constant periodic torque. In addition, the influence of gravitational field and viscous damping force of joint's bearings is taken into account. The numerical simulation, as well as the experimental studies revealed a wide spectrum of nonlinear phenomena. Chaotic, quasi-periodic and periodic orbits are detected and studied.