Figure 10.

a), b) Kelvin and c), d) error signal of an InAs nanowire similar to the device shown in Figure 9, measured with a standard integral controller, a) & c), and the Kelvin observer, b) & d). Feedback oscillations, as indicated by the arrow, are absent in the Kalman control scheme, while the standard deviation of the error signal also decreases from 0.19 to 0.13. (Scan parameters: A_free = 11.2 nm, A_set = 9.6 nm, Q = 500, k = 35 N/m, f₀ = 304.5 kHz, f_m = 4 kHz, U_ac = 2 V, f_cut = 50 Hz, n = 4, v_tip = 250 nm/s; all images show raw data).