“…Figure 9f shows the zoom-in position responses after settling, where the TWIP robot oscillated within about ±1 cm. Finally, the statistical data are shown in Table 2, where the mean absolutely error (MAE) and the root mean square error (RMSE) after the settling time are defined as (21) in which e indicates the corresponding error, T = 15 s, and t s is the settling time, when the error of the pitch angel is less than 0.475 o (i.e., 5% of the step from −9.5 • to 0 • ) afterwards. From the table, in place 1 and place 2, the rise time were 0.4 s, while the MAE and RMSE of ψ were less than 0.178 • and 0.224 • , respectively.…”