Designed and built a six-degree-of-freedom robotic manipulator for laboratory sample handling. The system required precise joint control, collision avoidance, and integration with an existing laboratory information management system.
Architecture
Each joint uses a custom BLDC motor controller running field-oriented control (FOC) on an STM32G4 microcontroller. Joint controllers communicate over a CAN bus with a central orchestrator running FreeRTOS. The high-level control stack runs ROS 2 for trajectory planning and inverse kinematics.
Key Challenges
- Thermal management in compact joint housings required careful PWM scheduling and active cooling
- Real-time guarantees on CAN bus with 6 joints + end effector sharing a 1 Mbps bus
- Calibration of kinematic parameters using a laser tracker for repeatability under 0.1 mm
Results
The system achieved ±0.05 mm repeatability and was deployed in a biotech lab automating PCR preparation workflows. The project went from concept to deployment in 14 weeks.