## 5 Experimental Result  
The experiment test platform was built to verify the control performance of the advanced DITC scheme, as shown in Figure 7. The entire experimental platform consists of the prototype, a torque and speed sensor, the magnetic power brake, the controller, the power supply, the PC, and an oscilloscope. As shown, the prototype, the torque and speed sensor, and the magnetic power brake are connected by two couplings. The signal obtained by the Hall sensor is sent to the controller; then, the controller outputs switch signals based on the control scheme after compilation. The rated speed and the phase voltage of the motor are 3000 r/min and 24 V, respectively. The main measuring equipment for the speed and torque is listed in Table 2. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Equipment** & **Type** & **Measuring Range** & **Measuring Error** \\ \hline Torque sensor & JN338 & 20 Nm & 0.2\% \\ \hline Speed sensor & JN338 & 18,000 r/min & 0.5\% \\ \hline Magnetic power brake & PB-A-1.2 & 12 Nm & 1\% \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Main measuring equipment. Figure 6: Optimization evolution of HWOA. The reference speed and load torque of the motor are set as 3000 r/min and 0.3 Nm, respectively. The experimental results of speed and torque performance using three different controllers applied in the DITC strategy are shown in Figure 8. As shown, the speed transient response of the DITC strategy using the proposed TSMC in the initial stage requires 0.09 s while PI and SMC take 0.18 s and 0.13 s, respectively. It can be reflected that the proposed scheme has less startup time and faster acceleration to reach the steady state, which verifies that the designed reaching law has faster convergence within the limited time. Moreover, the differences between the maximum and minimum torque in the steady state of the three controllers are 0.4 Nm, 0.36 Nm, and 0.3 Nm, respectively. Among them, the torque ripple range of the proposed TSMC can be reduced by 25% and 17%, respectively. It means that the proposed control scheme exhibits the best torque ripple suppression effect, which shows the effectiveness of the proposed reaching law in suppressing chattering. Therefore, the proposed TSMC has superiority in dynamic response and torque ripple reduction under this operation condition, which is consistent with the analytical theory. Figure 8: Experimental results under 0.3 Nm. (**a**) PI, (**b**) SMC, and (**c**) proposed TSMC. Figure 7: Experiment test platform. Figure 9 illustrates the experimental waveforms of the three controllers in the DITC strategy when the speed changes from 2000 r/min to 3000 r/min at 0.25 s under 0.3 Nm. As shown, the startup time of PI, SMC, and proposed TSMC are 0.2 s, 0.16 s, and 0.12 s, respectively. Consistent with the conclusion of the last condition, the proposed TSMC has the fastest approaching speed. In addition, it takes 0.15 s, 0.12 s, and 0.1 s for PI, SMC, and the proposed TSMC to reach a steady state after the speed change. It can be seen that the speed response of the proposed TSMC can be reduced by 33% and 17% when the speed variation occurs at 0.25 s, respectively. Similarly, the torque ripple reduction effect of the proposed TSMC is the most superior. Meanwhile, as for torque curves, the three schemes all have significant torque oscillations at 0.4 s. The torque ripple range of the three controllers under 800 r/min are 0.34 Nm, 0.32 Nm, and 0.28 Nm, respectively. Among them, the torque ripple range of the proposed TSMC can be reduced by 18% and 13%, respectively. With the change in speed, the torque ripple range in a steady state is not affected significantly. Obviously, the proposed TSMC displays better performance in aspects of speed response and torque ripple reduction under the variable speed condition. It can be found that the same conclusion as the above condition can be obtained, resulting from the advanced reaching law.