E&C Consultancy
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The LSR strokes the skin in two directions, at different velocities. The drag forces are logged, and displayed as a force~time graph. The difference between the average forward drag force, and the average reverse drag force is a measure of the dynamic friction. This gives us a differential measurement technique that removes common mode error such as a static force offset on the probe due to gravity. Friction is obtained by measuring the vertical load of the probe, and calculating the ratio of these two forces.
Experimentation has proven that the above technique does provide meaningful data.
In addition a new technique to measure static friction is under development. The motor drive force will be slowly increased until the point when the probe is able to move. The force acting to prevent movement will be logged, and displayed as a force~time graph. The trace showing the changes in force at 'take-off' is an indication of the effects that occur as a result of static friction. This is an experimental technique only at this time, and is not guaranteed to work.
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