# Inertial Propulsion of a Mobile Platform Driven by Two Eccentric Bodies
## 6 Experimental Proof of the Concept  
Following the simulation outcomes, the authors built a model of the Inertial Propulsion System. For this purpose, some of the simulation data were used to manufacture most of the parts by 3D printing from PLA filament, except for the shafts, bearings, and driving masses. The experimental tests on the IPS were carried out on a flat surface, on which a starting line was marked with colored adhesive tape. Parallel to this, other lines were drawn with  
Figure 5: Power consumption for driving the IPS. the same tape at distances of 300, 400, 500, 600, 700, and 1000 mm from the starting line. The thickness of the adhesive strip was 20 \(\upmu\)m in order not to influence the speed of the system when passing the strips. Time measurement was conducted with a high-speed camera at 1000 Fps. The experiments aimed to determine the average speed of movement of the equipment under the following conditions:  
* Traveling different distances and comparing the experimental data with the numerical simulation results;
* The variation of the drive speed of the eccentric bodies and the determination of its influence on the average speed of the vehicle;
* The variation of the mass of the eccentrics and the determination of its influence on the average speed of the vehicle. The speed was determined indirectly by measuring the time required to cover a known distance. For each distance, three measurements of time were conducted, with the average speed being computed as the ratio between the traveled distance and the average travel time. As mentioned before, the first tests aimed to measure the displacement speed of the IPS and compare it with the average speed obtained by simulation. Therefore, by driving the eccentric bodies with a 1000 rot/min speed, the device had to cover five different distances (300, 400, 500, 600, and 700 mm), with the necessary displacement time being recorded. Table 1 shows the experimental results, the computed average speed, the simulated average speed, and the percentage differences. As one can observe, the differences between the measured speed of the IPS and the simulated results are under 8%. This confirms both that the test procedure was correctly conducted as well as the correctness of the model and the simulation performed. Furthermore, the highest differences were noticed when traveling the shortest distance, where the time measurement was affected by higher errors. Additionally, the influence of the driving speed of the eccentrics on the vehicle's speed was investigated. For this purpose, the speed of the driving masses was set at four different values (500, 750, 1000, and 1500 rot/min), and the time for traveling 1000 mm was measured three times for each speed of the eccentric masses. Table 2 presents the time measurement results and the calculated average speed. The speed of the platform grows with the increase in the driving mass's speed. For instance, by doubling the speed of the driving masses (from 500 to 1000 rpm), the average speed of the platform increases 3.99 times (from 93.72 to 374.53 mm/s). Thus, Figure 6 \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Distance** & \multicolumn{3}{c}{**Measured Time [s]**} & **Average** & **Calculated Average** & **Simulated Average** & **Percentage** \\
**[mm]** & **t** & **t** & **t** & **Time \(\mathbf{t_{m}}\) [s]** & **Speed \(\mathbf{v_{m}}\) [mm/s]** & **Speed \(\mathbf{v_{s}}\) [mm/s]** & **Differences [\%]** \\ \hline
300 & 0.9 & 0.9 & 0.8 & 0.87 & 344.83 & & 7.05 \\
400 & 1.1 & 1.1 & 1.2 & 1.13 & 353.98 & & 4.57 \\
500 & 1.5 & 1.3 & 1.4 & 1.30 & 384.62 & 371 & 3.67 \\
600 & 1.7 & 1.7 & 1.6 & 1.67 & 359.28 & & 3.15 \\
700 & 1.9 & 1.9 & 2.0 & 1.97 & 355.33 & & 4.22 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Measurement of the average speed of the IPS.