Volume 21 Issue 09 - Publication Date: 1 September 2002
Velocity Dependence in the Cyclic Friction Arising with Gears
Elena Garcia and Pablo Gonzalez de Santos Industrial Automation Institute (CSIC) 28500 Madrid, Spain and Carlos Canudas de Wit Laboratoire d'Automatique de Grenoble 38 402 St. Martin d'Hères, France
Recent research on friction in robot joints and transmission systems has considered meshing friction a position-dependent friction component. However, in this paper we show experimental evidence that meshing friction depends highly on joint speed. We identify the meshing friction in the gearboxes of a robotic leg, and we propose a new mathematical model that considers the rate dependency of meshing friction. The resulting model is validated through experimentation. Results show that meshing friction is responsible for friction torque oscillations with an amplitude up to 25 percent of the average friction torque at low speeds. Therefore, this friction component should be taken into account if an accurate friction model is desired.
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