Experimental optimization of power-function-shaped drive pulse for stick-slip piezo actuators

Piezoelectric Inertia Motors—A Critical Review of History, Concepts, Design, Applications, and Perspectives

“…Anantheshwara et al [157] compared different sawtooth signals experimentally, and concluded that a high slider velocity at the end of the propulsion phase leads to large steps-a result consistent with the analytical investigation by Hunstig et al [91]. Neuman et al [93] and Shrikanth et al [247] obtained the same result in their numerical and experimental studies. Wang and Lu [166] investigated a motor which reached both larger maximum and smaller minimum steps with sawtooth excitation than with cycloid excitation.…”

“…When presenting experimental results, most authors present either single or averaged curves without any mention of the deviation which was almost certainly observed. Neuman et al [93] (p. 189) state that the standard deviation of their average velocity is below 5%. Curves obtained by the author [87] (pp.…”

“…A drawback of slip-slip operation is that wear-which is influenced significantly by the applied excitation signal [92]-is generally higher than in stick-slip operation using similar excitation signals due to the increased sliding distance. It is sometimes claimed in the literature that the coefficients of static and dynamic friction must be different for an inertia motor of either type to function (e.g., in [93] (p. 187)). It becomes clear that this is not necessary by taking a closer look at the slider movement in stick-slip operation (Figure 4a,b): in a horizontally operating motor as in Figure 1a, the maximum gradient of the rising flank (positive acceleration) of the slider velocityẋ S is…”

“…Generally, the normal force F z (t) produced by these mechanisms is constant over one actuation cycle. It is produced by permanent magnets (Figure 2d, [30,50]; [89] (p. 15f); [93,[139][140][141]) or by elastic deformation, for example, of metal springs (Figure 2a,c,e, [26,31,44,75,76,142]) or rubber rings (Figure 2b, [27,77,138]). The normal force generated by all these mechanisms can change over time due to wear, ageing, or creep.…”

“…It was independently used as the basis of a specialised simulation technique for such motors by Hunstig et al ([87] (pp. [85][86][87][88][89][90][91][92][93]; [264]). …”