taban/PIR_MadMax
2
4
Fork 0
Code Issues 4 Pull requests Projects Releases Packages Wiki Activity Actions

Merge branch 'abescat-patch-1'

Browse source
This commit is contained in:
Oskar Orvik 2026-05-13 19:58:14 +02:00
commit 7af9657162
1 changed files with 205 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

211
Article_Scientifique/main.tex
View file

@ -206,19 +206,157 @@ Third, the security of the wireless communication interface is investigated, wit
vulnerabilities. A Flipper Zero device is used as a diagnostic tool to evaluate potential attack surfaces and identify
weaknesses in the communication layer.
Finally, a dynamic model of the bicycle–cargo system is developed to improve rider experience.
Finally, a dynamic model of the bicycle-cargo system is developed to improve rider experience.
The objective is to minimize the perceived additional effort when towing a cargo cart. This is achieved through a
PID-based (Proportional–Integral–Derivative) control strategy combined with distance sensing, allowing adaptive
PID-based (Proportional-Integral-Derivative) control strategy combined with distance sensing, allowing adaptive
assistance based on system dynamics.
% ***************************** Hardware-Based Six-Step Commutation Controller ****************************************
% ************************************** LOW TECH SIX STEP CONTROL *****************************************************
\section{Hardware-Based Six-Step Commutation Controller}
% ***************************** STM32-Based Field-Oriented Control Motor Drive *****************************************
% ************************************** FIELD ORIENTED CONTROL *****************************************************
\section{STM32-Based Field-Oriented Control Motor Drive}
\label{sec:foc}
This section presents the design and implementation of a high-performance
motor controller based on Field-Oriented Control (FOC).
\subsection{Choice of FOC Over Trapezoidal Commutation}
Table~\ref{tab:foc_vs_trap} summarizes the key differences between the
two commutation strategies, based on the literature reviewed in
Section~\ref{sec:related}.
\begin{table}[htbp]
\caption{Comparison between FOC and trapezoidal (six-step) commutation}
\label{tab:foc_vs_trap}
\centering
\begin{tabular}{lcc}
\toprule
\textbf{Criterion} & \textbf{FOC} & \textbf{Six-Step} \\
\midrule
Torque ripple (at 500 rpm) & \SI{18.4}{\percent} & \SI{35.7}{\percent} \\
Low-load efficiency & High & Moderate \\
High-speed switching loss & Higher & Lower \\
Position sensor requirement & Encoder (high resolution) & Hall sensors \\
Implementation complexity & High & Low \\
Hardware cost & Higher & Lower \\
Dynamic response & Fast & Standard \\
\bottomrule
\end{tabular}
\end{table}
For our cargo bike application, rider comfort and smooth torque delivery
are priorities. FOC was therefore selected for the high-performance
controller, while a separate low-tech six-step board (Section~\ref{sec:sixstep})
was developed for repairability.
\subsection{Base Design: Cheap FOCer-2 Project}
The starting point was the open-source \textit{Cheap FOCer-2} project,
which provides a complete KiCad design for a VESC-compatible board based
on an STM32F405 microcontroller. This design includes:
\begin{itemize}
\item A three-phase MOSFET full-bridge power stage.
\item Gate drivers with built-in dead-time insertion.
\item Shunt resistors for phase current sensing.
\item USB and CAN interfaces.
\item An expansion header for encoder or Hall sensors.
\end{itemize}
The existing KiCad schematic and layout were used as the baseline for
our adaptations.
\subsection{Integration of the Rocacher FOC Tile}
Mr. Rocacher provided the Kicad schematic of a ready-to-use FOC tile based on an STM32L476
microcontroller.
The initial idea was to make this tile \textit{pluggable} into our
carrier board, similar to an Arduino shield. This would allow :
\begin{itemize}
\item Easy replacement of the computing core without re-soldering.
\item Modular upgrades of the microcontroller.
\item Simplified repair and maintenance.
\end{itemize}
However, the Cheap FOCer-2 project was not designed for such modularity.
Its routing is dense and highly optimized for a single, non-removable
F405 chip. Adapting it to accept an L476 tile while preserving all
critical functions (PWM, current sensing, USB communication) proved
challenging.
\subsection{Pin Compatibility Verification: L476 vs F405}
Before modifying the PCB, a thorough pin compatibility check was
performed between the STM32L476 and the STM32F405
(original Cheap FOCer-2 design). The following aspects were examined:
\begin{itemize}
\item Physical pinout in LQFP64 package.
\item Alternate functions for PWM timers.
\item USB DP/DM pins (PA11/PA12).
\item Analog inputs for current sensing.
\item UART for BLE communication.
\end{itemize}
Three pin conflicts were identified and resolved as follows.
First, the SPI\_MISO function on PA6 for the STM32F405 conflicts with a
DAC output on the same pin for the STM32L476 tile. Since this pin is
used for current sensing via SPI in the original Cheap FOCer-2 design,
the SPI communication was remapped to PA5 on the L476, which provides a
compatible alternate function.
Second, the gate driver enable signal (EN\_GATE) was originally assigned
to PB5 on the F405. This pin is not accessible on the L476
tile. The signal was therefore moved to PC5, which is available and
can be configured as a standard GPIO output.
Third, Hall sensor C was originally connected to PC8 (TIM8) on the F405.
This pin is not available on the L476 tile. The Hall sensor input was
therefore reassigned to PB3, configured as TIM2\_CH2, which provides
the necessary input capture functionality for Hall signal decoding.
All other critical functions (PWM timers, complementary PWM, enable
signals, encoder inputs, UART, USB, and CAN) remain fully compatible
between the two microcontrollers. The ADC channel differences between
the F405 (ADC123/ADC12) and the L476 (ADC3) must still be handled in
firmware, as noted previously.
\subsection{Schematic Design and KiCad Implementation}
The original Cheap FOCer-2 schematic was modified in KiCad to replace the
integrated F405 with connectors for the L476 tile. The main modifications
included:
\begin{itemize}
\item Removal of the F405 and its associated passive components.
\item Addition of two 20-pin headers to receive the Rocacher tile.
\item Re-routing of PWM, ADC, and USB signals to the headers.
\end{itemize}
The schematic passed Electrical Rule Check (ERC) with no errors.
\subsection{Routing Challenges and Current Status}
The PCB layout was then started. The original Cheap FOCer-2 routing is
very dense. Inserting connectors for the removable tile while maintaining signal integrity proved
difficult.
The main issues encountered were:
\begin{itemize}
\item Some footprints for the tile connectors did not appear correctly
in the layout after schematic import.
\item Routing of high-current paths (battery, motor phases) around the
connectors required additional vias, increasing resistance.
\item Decoupling capacitors had to be repositioned, raising concerns
about switching noise.
\end{itemize}
Currently, the schematic is validated, and the layout is under
development. Once routing is completed, the board will be manufactured
and tested with the VESC firmware adapted to the L476 tile.
% ************************************** SOFTWARE AND CONNECTIVITY *****************************************************
@ -304,7 +442,7 @@ for the the MAD associates.
% ************************************ DYNAMIC MODELLING ***************************************************************
\section{Dynamic Modelling and Control of the Bicycle–Cargo System}
\section{Dynamic Modelling and Control of the Bicycle-Cargo System}
\subsection{Dynamic System Modelling}
@ -376,7 +514,7 @@ where $e_{\text{ref}} = \SI{-0.5}{\meter}$ represents the desired equilibrium of
\centering
\includegraphics[width=\linewidth]{./Figures/sys_dyn_matlab.png}
\caption{Closed-loop model of the bicycle–cargo system with PI control.}
\caption{Closed-loop model of the bicycle-cargo system with PI control.}
\label{fig:simulink-closedloop}
\end{figure}
@ -443,6 +581,33 @@ However, due to the absence of direct velocity measurements during the experimen
be extracted from these tests. Consequently, a precise estimation of dynamic friction parameters and energy efficiency
could not be achieved.
\subsection{FOC Controller Validation}
\subsubsection{Current Status Summary}
Table~\ref{tab:foc_status} summarizes the current status of the FOC
controller development.
\begin{table}[htbp]
\caption{FOC controller development status}
\label{tab:foc_status}
\centering
\begin{tabular}{l c}
\toprule
\textbf{Task} & \textbf{Status} \\
\midrule
VESC firmware compilation & Completed \\
Pin compatibility (F405 / L476) & Completed \\
Schematic design (KiCad) & Completed \\
ERC validation & Completed \\
PCB routing & In progress \\
Tile footprint correction & In progress \\
Board manufacturing & Planned \\
Hardware testing & Planned \\
\bottomrule
\end{tabular}
\end{table}
% ******************************** DISCUSSION **************************************************************************
@ -476,6 +641,19 @@ What should be a clear conclusion from our test with the jammer is that a contro
avoided when possible and practical. Examples where this could be relevant include electric skateboards, as cables could
impose a tripping hazard. There, an encapsulation of an encrypted control frame could be an thought.
% ******************************** Perspectives and Future Work ************************************************************
\section{Perspectives and Future Work}
Based on the results obtained and the limitations identified during this
project, several directions for future work are proposed.
\subsection{Hardware Completion and Testing}
The VESC-based FOC PCB requires routing completion and prototype
manufacturing. Once fabricated, the board must be tested under real
operating conditions (varying loads, road profiles, and battery voltage).
% ******************************** CONCLUSION **************************************************************************
\section{Conclusion/Summary}
@ -495,8 +673,29 @@ impose a tripping hazard. There, an encapsulation of an encrypted control frame
%quantities and units. For example, write ``Temperature (K)'', not
%``Temperature/K''.
% ******************************** REMERCIEMENTS **************************************************************************
\section*{Acknowledgment}
The authors would like to thank Pascal Acco and Thierry Rocacher for their
continuous technical guidance and support throughout this project. Their
expertise in power electronics, embedded systems, and PCB design was
invaluable.
We also thank La Manufacture Autonome Décentralisée (LaMAD) for providing
the use case, the technical requirements, and the cargo bike platform used
for validation.
Finally, we acknowledge the INSA Toulouse GEI department for providing
access to laboratory facilities, measurement equipment, and the necessary
components for prototyping.
This work was carried out as part of the 4th-year research project (PIR)
at INSA Toulouse.
% ******************************** IA **************************************************************************
\section*{Statement on AI Usage}
The authors acknowledge the use of generative AI tools during this project, both for the development work and for
writing this paper.