Short answer: Robotics control electronics combine six blocks on one or a few boards: motor drivers for BLDC/PMSM, stepper or servo motors with field-oriented control; current and position sensing fast enough for 10–50 kHz control loops; a functional-safety layer with safe torque off, emergency stop and redundant monitoring designed to ISO 13849 or IEC 62061; interfaces for sensors and cameras (CAN, EtherCAT, Ethernet, MIPI CSI, USB); a power tree from a 24 or 48 V bus with regeneration handling and protection; and real-time firmware that closes the loops and supervises the system. Comtec Labs designs, prototypes and manufactures this electronics, including the embedded control firmware, for industrial and autonomous machines.
The six blocks and their design decisions
| Block | Typical choices | What decides the choice |
|---|---|---|
| Motor drive | Integrated gate drivers + MOSFET bridges, 24–48 V, 5–50 A; FOC on MCU or dedicated motor-control MCU | Torque, speed, efficiency, size, thermal budget |
| Sensing | Shunt or Hall current sensing, magnetic or optical encoders, IMU | Loop bandwidth, position accuracy, cost |
| Safety | STO inputs, dual-channel e-stop, safe MCU or redundant monitoring MCU, brake control | Required performance level (PL) / SIL, risk assessment |
| Interfaces | CAN/CANopen, EtherCAT, Ethernet, RS-485, MIPI CSI-2 cameras, USB, GPIO | Number of axes, sensors, latency, cabling |
| Power | Bus pre-charge, reverse and overvoltage protection, regeneration dump, isolated logic supply | Battery or mains, motor energy, EMC |
| Compute and firmware | Cortex-M7/M33 for loops, Cortex-A or NPU for perception, RTOS, real-time scheduling | Control rate, perception load, safety partitioning |
Motor control in practice
- Field-oriented control (FOC) of BLDC/PMSM motors gives smooth torque and high efficiency; it needs phase current sensing and a rotor position estimate every 50–100 µs.
- Current loops run at 10–50 kHz, position loops at 1–10 kHz; the MCU, ADC timing and PWM design are chosen for that, not the other way round.
- Regeneration: a decelerating axis pushes energy back to the bus; the power design must absorb it (bulk capacitance, brake chopper or battery) or the bus voltage will trip protection.
- Thermal design is part of the schematic: MOSFET losses, copper area, vias to a heat spreader and the enclosure decide the continuous current rating.
Safety is a hardware architecture, not a firmware feature
A safe torque off path that removes gate drive power independently of the main MCU, dual-channel emergency stop inputs, cross-monitoring between two controllers and a defined safe state at power-up and fault are designed into the schematic. Which level (PL c/d/e per ISO 13849-1, SIL 2/3 per IEC 62061) is derived from the machine's risk assessment; the electronics then have to prove it. Comtec Labs designs these paths with the customer's safety engineer and documents them for the machine's technical file.
Key facts
- FOC current loops at 10–50 kHz set the MCU, ADC and PWM requirements for the whole board.
- Regeneration handling is the most common cause of field failures in first-generation robotic drives.
- Safety functions (STO, e-stop) must be independent of the application MCU to reach PL d/e.
- Comtec Labs delivers robotics control boards, motor-control electronics, sensor and camera integration, embedded control firmware and series PCBA production.
How we run a robotics electronics project
Requirements from the mechanics and the safety assessment, an architecture with motor, sensing, safety and compute partitions, a prototype board with the control firmware, bench testing on the actual motors, EMC pre-compliance, then pilot and series production with functional test on the line. Our customers include marine, mobile-machinery and industrial automation companies.
Frequently asked questions
Can one board drive several motors?
Yes. Multi-axis boards with 2–6 drives are common; beyond that, per-axis drives on a CAN or EtherCAT bus scale better and keep power and heat distributed.
Do you develop the control firmware too?
Yes: FOC, motion profiles, bus communication, safety supervision and the production test firmware.
What voltage should a mobile robot use?
24 V for small platforms and simple safety; 48 V for higher power with lower current, cabling and losses while staying below the 60 V DC safety extra-low-voltage limit.
Can you help with the safety certification?
We design the safety-related hardware to the target performance level and provide the documentation; certification of the machine is done with the customer and a notified body where required.
Ready to reduce PCB surprises?
Comtec Labs offers a full suite of services to streamline your workflow:
PCB design service
PCB prototyping service
PCB component sourcing
PCB component assembly
PCB testing service
PCB repair and modifications
Printed circuit board production
PCB mass production