Simulation and Measurements of Stick-Slip-Microdrives for Nanorobots

Edeler, Christoph and Meyer, Ingo and Fatikow, Sergej
This paper presents the results of measurements and simulations of a linear stick-slip axis for a mobile nanorobot for the height adjustment of end-effectors, e.g. microgrippers. The function is dependent on surface condition and friction characteristics. The axis is driven by laserstructured piezoceramics, who generate a dynamic stick-slip motion. It is shown, that the dependency to surface etc. can be partly described by a phenomenon that will be denominated 0(zero)-step amplitude. It is the amplitude, where an actuator displacement is generated, but the final step length remains precisely zero. To investigate several influences on the 0-step amplitude, a test stand was build up. For simulation of friction according to literature dedicated to micro- and nanorobots, friction contacts can be modeled using the LuGre-model of friction. However, the 0-step amplitude is not covered by the model. Furthermore, the dependency to surface condition is not part of actual friction models. Thus, this effect is systematically measured and finally it is discussed how to integrate it into available friction models.
09 / 2010