## 6 Conclusions  
This paper applied the methodology for determining the amount of energy recuperated via regenerative braking in several racetracks for a student-built electric racing motorcycle prototype (TLM03e) for the MotoStudent competition. A developed software MATLAB (Matlab R2022a version) simulated lap times around all of the tracks, including initial and flying laps. With the obtained velocity time series and, using a percentage of 30% of rear regenerative braking, a developed MATLAB/Simulink software (Matlab R2022a version) determined the results of recuperated energy per circuit. Sensitivity analyses of the percentage of rear braking and the mass of the prototype plus the rider were performed to help draw more conclusions. Results show the following:  
* Recuperated energy values range from 7.88% to a maximum of 14% with an average of 11.11% recovered per circuit, which translates into an average traveled distance increase of 8.8%. * Recuperated energy depends strongly on the average speed of the circuit, slightly on the lap distance and not at all on the number of turns. If average track speeds are  
Figure 19: Recovered energy results for 100% regenerative braking. \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Total Mass = 209 kg** & **Total Mass = 220 kg** & **Total Mass = 231 kg** \\ \hline Rec. En. & 12.03\% & 12.21\% & 12.45\% \\ \hline Total Distance & 40.527 km & 39.635 km & 38.886 km \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Sensitivity analysis results for several mass values and a percentage of rear braking of 30%. lower, more braking scenarios occur and, therefore, higher regenerated energy values are expected. * A sensitivity analysis leads to a conclusion that increasing 5% of the percentage of regenerative braking results in increases of 666 m in traveled distance for the Catalunya circuit. If the percentage of rear braking were to suffer a decrease of the same magnitude, the traveled distance would decrease by 634 m.
* A sensitivity analysis on the weight of the system revealed that diminishing the weight from 220 kg to 209 kg (5%) leads to a 0.18% decrease in recuperated energy results. If the mass were to increase by the same amount, recuperated energy results would increase by 0.24%. * Regenerative systems can provide the vehicle with significant recuperated energy values, according to the cases studied in this paper. These allow the TLM03e prototype to run one more lap in almost every circuit, using 100% of its power and 30% regenerative braking. If endurance is the sole purpose of a race, values higher than 30% regenerative braking can be used, which, combined with a lower power usage, will result in a very good distance increase. In a racetrack, elevation differs several meters from the starting value during a lap. When not accounting for this variation, the velocity and, consequently, kinetic energy are overestimated. Hence, future work can include the height (and inclination) values of the racetracks. Since almost 70% of the braking force is applied on the front wheel, it would be of scientific interest to study solutions that redirect some of that energy to the regenerative braking system as well in future work. The validation of the theoretical results with experimental data is very interesting and of the utmost importance. However, the utilization of regenerative braking systems in motorcycles is quite new, and experimental results in racing scenarios are not publicly accessible. Due to this issue's relevance, it is certainly one that will be addressed in future work. Conceptualization, N.R. and R.C. ; methodology, N.R. ; software, N.R. ; validation, N.R. and R.C. ; formal analysis, N.R. ; investigation, N.R. ; resources, R.C. ; data curation, N.R. ; writing--original draft preparation, N.R. ; writing--review and editing, R.C. ; visualization, R.C. ; supervision, R.C. ; project administration, R.C. ; funding acquisition, R.C. All authors have read and agreed to the published version of the manuscript.