Project objective
The objective was to design a compact embedded servo-controller concept that connects electronics, firmware, position sensing, motor-drive hardware, and mechanical packaging constraints. The project is focused on the practical design decisions required before a small BLDC actuator can be controlled reliably.
Design requirements
- Design a compact controller suitable for a small BLDC servo-style actuator.
- Integrate STM32 control, DRV8313 motor-drive hardware, and TMR magnetic angle feedback.
- Keep the PCB practical for motor-current routing, sensing integrity, voltage regulation, and firmware bring-up.
- Provide programming access, debug points, connectors, and fault-handling paths.
- Plan for closed-loop position control from measured rotor angle to motor command.
- Avoid treating the board as only a schematic exercise by considering packaging, manufacturability, and testing.
System overview
The board concept centres on an STM32 microcontroller commanding a DRV8313 three-phase motor driver, with a TMR magnetic angle sensor providing rotor-position feedback. The design has to balance power routing, signal integrity, thermal behaviour, programming access, and a compact actuator footprint.
- Microcontroller
- STM32 for firmware, PWM, communication, and fault handling
- Motor driver
- DRV8313 three-phase BLDC driver
- Feedback
- TMR magnetic angle sensing for rotor position
- Power
- Local regulation and motor-current routing
- Control
- Closed-loop position-control concept
- Bring-up
- Programming access, debug points, test pads, and validation plan
My technical contribution
- Defined the embedded servo-controller architecture and major functional blocks.
- Selected and arranged the microcontroller, motor driver, TMR angle-sensing path, voltage regulation, connectors, and debug access concept.
- Considered PCB layout priorities including motor-current loops, grounding, sensor placement, thermal paths, and manufacturability.
- Planned the firmware/control structure needed to move from sensor feedback to PWM motor-drive commands and fault handling.
Technical detail
This project is interesting because the electrical, mechanical, and firmware decisions are tightly coupled. Sensor placement affects angle quality, routing affects motor-drive noise, available debug access affects bring-up, and the control strategy depends on reliable feedback from the board.
The control concept follows a feedback loop: read rotor angle, compare against a commanded position, compute a control output, generate PWM, drive the motor through the DRV8313, monitor faults, and repeat at a rate suitable for stable actuator behaviour.
Results and evaluation
The project produced a clear embedded servo-controller architecture and design direction for a compact BLDC actuator board. It meets the initial objective at design level by identifying the major control, sensing, power, and PCB-layout constraints needed for implementation. The main remaining evaluation work is physical board bring-up: validating sensor readings, motor-drive behaviour, firmware timing, thermal performance, and closed-loop position response.
Visual gallery
Future improvements
- Complete schematic and PCB layout screenshots suitable for public presentation.
- Assemble and bring up the PCB with staged tests for power, programming, sensing, PWM, and motor-drive behaviour.
- Validate angle sensor quality, motor phase switching, driver faults, thermal behaviour, and supply stability.
- Implement and tune the closed-loop position-control firmware.
- Add board renders, bench photos, oscilloscope captures, and step-response plots when available.