Magnesium carbonate and rosin powders stabilize sliding motion between rubber-gloved human hand and grasped cylindrical bar

Abstract

We investigated the effect of magnesium carbonate and rosin powders, conventionally used as anti-slip agents, for the ease of controlling the sliding motion of a stainless steel bar grasped vertically by a hand wearing a rubber glove. Fifteen participants were instructed to slide the stainless steel bar downward with their dominant hand and control the sliding speed to be constant by controlling their grip force, and stop the bar 0.2 m from the starting point within 5.0 s. Sliding control tests were conducted under six conditions of the interface between gloved-hand and the bar: dry without powder, dry with MgCO3 powder, dry with rosin powder, wet without powder, wet with MgCO3 powder, and wet with rosin powder. The bar sliding motion was captured and the time of arrival, total sliding distance of the bar, and standard deviation of the sliding velocity of the bar were calculated. The friction force between sliding bar and gloved-hand was estimated from the bar sliding motion. The controllability of the sliding motion of the bar was evaluated by sensory assessment. The sliding control test indicated that both powders reduced the variation in sliding velocity of the grasped bar and improved the controllability of its sliding motion compared with unpowdered dry and wet conditions. Powder application also decreased variation in the friction force between the rubber-gloved hand and the grasped bar during sliding under dry and wet conditions. These results suggest that both powders stabilize friction, thereby improving the sliding control of a grasped bar.