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Assessment of gait stability and preferred walking speed in virtual reality

Wodarski Piotr, Jurkojć Jacek, Polechoński Jacek, Bieniek Andrzej, Chrzan Miłosz, Michnik Robert, Gzik Marek

Acta of Bioengineering and Biomechanics

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2020

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Vol. 22, no. 1

127--134

EN

Analysis of human gait as well as diagnosis of human locomotion organ should always be conducted with velocity of gait equal to Preferred Walking Speed (PWS). The literature review shows that the PWS value is not the same in real and virtual environment. The aim of this study was to determine PWS values in both environments and to specify values of parameters used in equations enabling PWS calculations on the basis of lower limb length. Methods: Research-related tests involved 40 subjects walking on the treadmill and wearing HMD goggles. The spatial scenery made participants feel like during a walk in the park. The tests included measurements of displacements of the COP, allowing for the calculation of the Lyapunov exponent and Floquet Multiplier. Both coefficients were used to identify stability at various gait velocities. Results: The analysis revealed that the PWS in relation to gait on the treadmill with VR was lower than the PWS without VR. The final stage of research involved the determination of new values of coefficients of the formula enabling the identification of the velocity of comfort of gait in VR. Conclusions: Obtained results proved that PWS in real and virtual environment are different. The lower values were obtained for measurements in VR. On the basis of these results, value of the “a” coefficient, used in PWS calculations on the basis of lower limb length, was re-determined. The new value makes it possible to assess PWS for gait conducted on treadmill in virtual environment, what can be very important in gait evaluation.

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

Model chodu robota dwunożnego w środowisku Matlab

Hudziak W., Góra M.

Mechanik

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2014

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R. 87, nr 2CD

PL

Opracowano model robota dwunożnego w oparciu o wzorzec biologiczny - kończyny dolnej człowieka. Na przykładzie robota dwunożnego omówiono sposób doboru struktury pojedynczego odnóża w zależności od funkcji jakie ma wykonywać. Dokonano analizy wpływu zmiany współrzędnych przegubowych na położenie stopy robota. Zbudowano model graficznych robota kroczącego w środowisku V-Realm Builder – Matlab. Przedstawiono przykłady modelowania chodu robota dwunożnego w warunkach zachowania stabilności statycznej i dynamicznej.

EN

Biped robot model was developed based on the biological model of human lower limb. Based on two-legged robot example, a selection method of single leg structure, depending on the functions they are to perform, is illustrated. An analysis of influence of the joint coordinates changes on the location of the robot feet. The model of walking robot in a graphical environment, the V-Realm Builder – Matlab, was built. The examples of modeling bipedal walking robot behavior under static and dynamic stability conditions.

4

Postural stability in symmetrical gaits

Zielińska T., Trojnacki M.

Acta of Bioengineering and Biomechanics

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2009

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Vol. 11, nr 2

57-64

EN

In this paper the method of stability analysis of dynamic symmetrical gaits is discussed. The problem of dynamic postural equilibrium, taking into account the role of compliant feet, is solved. The equilibrium conditions are split between the foot attachment points and the points within the foot-end area. The present method is useful for motion synthesis, taking into account robot parameters. It also helps in the robot foot design. As an illustrative example a four-legged diagonal gait is considered. The theoretical results were verified by implementing and observing the diagonal gait in four-legged machine with and without feet.

5

ZMP and GCOM criteria as a base of assessment of the human gait stability

Mrozowski J., Awrejcewicz J.

Zeszyty Naukowe Katedry Mechaniki Stosowanej / Politechnika Śląska

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2006

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z. 26

253-258

EN

An analysis of the gait stability of the man moving along an even surface with a constant velocity is presented. The stability criteria applied to biped robots, namely: the ZMP (Zero Moment Point) and the GCOM (Ground projection of the Center Of Mass) have been employed in the investigations. The analysis has been carried out on the basis of the measurement data obtained from the human gait recorded with two digital camcorders.

6

Stability of the Human Gait

Mrozowski J., Awrejcewicz J., Bamberski P.

Vibrations in Physical Systems

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2004

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Vol. 21

271--274