Performance evaluation. (A) Boxplots of the tracking error for each interface. The dashed horizontal lines indicate reference values of the tracking error. (B) Boxplots of the gain margin crossover frequency for each interface. (C) Boxplots of the information transmission rate for each interface. (D) Boxplots of the RMS of the velocity signal for each interface. The dashed horizontal line indicates the RMS of the optimal u signal. Stars indicate statistically significant differences. (*) indicates p <0.05, (**) indicates p <0.001.