# Optimization of Mode-Switching Quality of Hybrid Tractor Equipped with HMCVT
## 5 Conclusions  
In this paper, the proposed hybrid tractor powertrain configuration equipped with hydraulic-mechanical continuously variable transmission device was the research goal. The control strategy of \"clutch oil pressure fuzzy control + motor torque compensation\" has been proposed, and the quality of vehicle mode switching optimized and verified by using orthogonal test range analysis and variance analysis. The following three conclusions can be drawn: \begin{table}
\begin{tabular}{c c c c c c c} \hline
**Origin** & **df** & **Adj SS** & **Adj MS** & **F Value** & **\(p\) Value** & **Eminence** \\ \hline Factor A & 2 & 0.226 & 0.113 & 1.67 & 0.230 & \\ Factor B & 2 & 0.140 & 0.071 & 1.04 & 0.384 & \\ Factor C & 2 & 0.724 & 0.362 & 5.35 & 0.022 & ** \\ Factor D & 2 & 1.137 & 0.568 & 8.41 & 0.005 & *** \\ Factor E & 2 & 1.696 & 0.848 & 12.54 & 0.001 & *** \\ Factor F & 2 & 0.044 & 0.022 & 0.32 & 0.730 & \\ Factor G & 2 & 0.062 & 0.031 & 0.46 & 0.644 & \\ Error e & 12 & 0.811 & 0.068 & & & \\ \hline \end{tabular} Note: In the table: when \(p<0.01\), the significance is ***; when \(0.01\leq p<0.05\), the significance is **.  
\end{table} 
Table 4: Switching time analyzed by variance method. \begin{table}
\begin{tabular}{c c c c c c} \hline
**ca** & **ei** & **Speed Drop** & **Dynamic Load Factor** & **Impact Strength** & **Switching Time** \\ \hline \multirow{4}{*}{sa} & bs & E\({}_{1}\)C\({}_{3}\)A\({}_{2}\)D\({}_{3}\)B\({}_{1}\)F\({}_{3}\) & E\({}_{1}\)C\({}_{3}\)D\({}_{3}\)F\({}_{2}\)A\({}_{3}\)B\({}_{3}\) & C\({}_{3}\)A\({}_{1}\)E\({}_{1}\)F\({}_{2}\)B\({}_{1}\)D\({}_{3}\) & E\({}_{1}\)D\({}_{3}\)C\({}_{3}\)A\({}_{2}\)B\({}_{2}\)F\({}_{2}\) \\ \cline{2-6}  & \multirow{4}{*}{fp} & EC major & EC major & CED major & EDC major \\  & & AD mid & DF mid & B mid & AB mid \\  & & BF minor & AB minor & FA minor & F minor \\ \hline \multirow{4}{*}{tv} & bs & C\({}_{1}\)E\({}_{3}\)A\({}_{2}\)D\({}_{3}\)B\({}_{1}\)F\({}_{3}\) & E\({}_{1}\)C\({}_{3}\)D\({}_{3}\)F\({}_{2}\)A\({}_{3}\)B\({}_{3}\) & E\({}_{1}\)D\({}_{3}\)C\({}_{2}\)A\({}_{3}\)B\({}_{1}\)F\({}_{3}\) & E\({}_{1}\)D\({}_{3}\)C\({}_{2}\)A\({}_{3}\)B\({}_{1}\)F\({}_{3}\) \\ \cline{2-6}  & \multirow{4}{*}{fp} & CEA major & E major & EDC major & ED major \\  & & D mid & CD mid & AB mid & C mid \\ \cline{1-1}  & & BF minor & FAB minor & F minor & ABF minor \\ \hline \end{tabular} Note: In the table: ca stands for comparative analysis; ei stands for evaluation index; sa stands for simulation analysis; bs stands for best solution; fp stands for factor priority; iv stands for test verification.  
\end{table} 
Table 5: Comparative analysis of simulation results and test results. In the process of switching from pure electric mode to hybrid speed-coupling mode, the control strategy of \"clutch oil pressure fuzzy control + motor torque compensation\" was proposed. SimulationX and Matlab/simulink software were used for joint simulation verification. The simulation results show that the control strategy reduced the output shaft velocity drop amplitude from 21.875% to 18.755%, the dynamic load coefficient from 8.473 to 7.573, and the impact strength from 26.181 m/s\({}^{3}\) to 21.581 m/s\({}^{3}\). The switching time was reduced from 1.345 s to 1.301 s.  
L\({}_{27}\)(3\({}^{6}\)) orthogonal table was used for the orthogonal test design, and MINITAB software was used to carry out range analysis on the simulation results. The analysis showed that A\({}_{3}\)B\({}_{1}\)C\({}_{3}\)D\({}_{3}\)E\({}_{1}\)F\({}_{2}\) was the optimal switching scheme, the output shaft velocity drop amplitude was reduced from 18.755% to 1.63%, and the dynamic load coefficient was reduced from 7.573 to 2.72. The impact strength was reduced from 21.581 m/s\({}^{3}\) to 7.08 m/s\({}^{3}\), and the switching time was reduced from 1.301 s to 0.35 s. The optimal scheme effectively improved the quality of mode switching. A hardware-in-the-loop test scheme was designed and a hardware-in-the-loop simulation test was carried out. The results were analyzed by orthogonal test and arranged in blank columns.