Jurij Wakula

Ergonomic Analysis of Grapevine Pruning and Wine Harvesting to Define Work and Hand Tools Design Requirements

Quantitative and qualitative knowledge of ergonomic analysis of grapevines pruning and wine harvesting with respect to postural load, repetitive movements of cutting hand and using different cutting tools was obtained. It could be demonstrated, that stress generated by working postures and repetitive movements combined with were a major problem of work., Ergonomic design deficits of the existing cutting hand tools was carried out.

Stress-Strain- Analysis of Grapevine Pruning with Powered and Non-Powered Hand Tools

Non-power and power cutting hand tools are mainly used every day in vineyards for grapevines pruning during 5 months (November - March). The grapevines pruning with the help of non-power tools is very stressful for wine growers. Repetitive movements combined with external forces in finger-hand-wrist-system, extreme positions in arm-shoulder-system, climate condition are some of the stress factors. Grapevines pruning with 5 manual prunes produced by 3 different manufacture and 2 power hand tools (electrically and pneumatically) were analysed. The results reveal that grapevines pruning with pneumatic and electric prunes is up to 30% more effective (according to productivity) than cutting with non-powered hand tools. At the same time is grapevines cutting with power tools more stressful as with non-powered one.

Analysis of Physical Workloads and Muscular Strain in Lower Extremities During Walking “Sideways” and “Mixed” Walking in Different Directions in Simulated U-Shape in the Lab

The muscular strain at the lower extremities was analysed in the IAD-lab using the simulated U-shape with short-cycle tasks (approx. 80 s.) with walking “sideways” and “mixed” walking (sidesteps and normal steps). Also focus was on analysis of the effects of “walking sideways counter clockwise” vs. “turn clockwise sideways” on the muscular strain in the three selected muscles in the right and the left leg. Four different scenarios were tested. The U-shape consisted of five work stations, was 2 m long and 1.4 m wide in scenarios walking with “sidesteps” (A, B) only. In scenarios with “mixed” walking the assembly U-shape was about 3,2 m long and 1.4 m wide. The EA-activities in selected three leg muscles in the left and right legs were analysed using surface EMG-method. Six test subjects, between 19 and 30 years old, without experience in assembly work took part in the study. The results complement the study Wakula et al. (2017a,b) and show that walking “sideways” counter-clockwise (CC) cause the selected right leg muscles more strain compared to the left leg muscle by some test persons. When walking clockwise (C) two muscles in the left leg were more stressed compared to the right leg muscles. Changing the direction of moving at the U-line: CC \( \to \) C \( \to \) CC \( \to \) C is positive for the muscular strains - it brings some balance of the EA values in analyzed right and left leg muscles. Walking with “mixed” (lateral and two-three normal) steps in the analyzed U-shape did not reduce muscular strains in the legs compared to walking with “sidesteps” only.

Walking “Normally” vs. “Sideways” in Simulated, Simple Assembly Operations: Analysis of Muscular Strain in the Legs

The muscular strain of the lower extremities when walking “normally” and “sideways” was analysed using the simple, simulated U-assembly line in the Laboratory of the Institute for Ergonomics and Human Factors in Darmstadt (IAD). Test subjects executed their assembly operations in different scenarios in two studies. The U-line in the first study consisted of three work stations and five work stations in the second one. Electrical activities (EA) in six leg muscles on each leg (left and right) were measured and analysed by using EMG method. Ten test subjects without experience in assembly work took part in both studies. The results in the first study show that walking “sideways” puts lower extremities under more stress than walking “normally” does. We were able to record higher electrical activities values (especially dynamic EA-shares) in four out of six analysed leg muscles. EMG-results in the second study show that when “walking sideways counter-clockwise”, three muscles on the right leg are under greater stress than the muscles on the left leg.