2025-04-10

How to design PCBs for collaborative robots

author: Eric

How to Design PCBs for Collaborative Robots: Key Considerations & Best Practices

1. Why Collaborative Robots Demand Unique PCB Solutions

Collaborative robots (cobots) operate alongside humans in factories, labs, and hospitals, requiring PCBs to balance precision, safety, and durability. Key challenges include：
  • Human Interaction: Circuits must enable real-time force sensing and emergency stops.
  • Space Constraints: Compact designs for lightweight arms (e.g., <10kg payload models).
  • Certification Complexity: Meeting ISO 13849 (PLd) and IEC 61508 (SIL 2) safety standards.

2. 5 Essential PCB Design Principles for Cobots

2.1 Safety-First Circuit Architecture

  • Redundant Systems: Dual-channel monitoring for critical components like motor drivers.
  • Fail-Safe Mechanisms：
           Current-limiting circuits (≤100mA thresholds) to prevent actuator overloads.
           Watchdog timers to auto-reset unresponsive microcontrollers.

2.2 Signal Integrity in Noisy Environments

  • Impedance Control：

           90Ω differential pairs for vision camera interfaces.
           50Ω single-ended traces for SPI/I²C sensor buses.

  • EMI Mitigation：

           4-layer stackups with dedicated ground planes.

           Ferrite beads on PWM lines driving brushless DC motors.

2.3 Thermal Management for Continuous Operation

Component
Cooling Solution
Performance Gain
Motor Drivers
Aluminu-core PCBs(2-4W/mK)
40% lower hotspot temps
AI Processors
Heat pipes+thermal vias
25% longer MTBF

2.4 Vibration-Resistant Layouts

  • Mechanical Reinforcement：

          Edge-mounted connectors (e.g., screw-lock types).
          Avoid large BGA packages near mounting points.

  • Conformal Coating：IPC-CC-830B compliant coatings for moisture/dust protection.

2.5 Compliance-Driven Component Selection

  • Certified Safety Controllers：Dual-core MCUs with TÜV/UL pre-certification.

  • Industrial-Grade Sensors：IP67-rated proximity/force sensors.

3. Top 3 Industry Standards You Can’t Ignore

  1. ISO 13849-1：

      Mandates redundant circuits for PLd-rated cobots.

      2.CISPR 32 Class B：

      Limits EMI emissions from motor control modules.

       3.IEC 61340-5-1：

      ESD protection for PCBs in dry manufacturing environments.

4. Real-World Application Case

A medical cobot manufacturer achieved zero field failures by：
  • Using 6-layer PCBs with separate analog/digital grounds.
  • Implementing thermal vias under MOSFETs (0.3mm filled vias).
  • Passing 100-cycle thermal shock tests (-40°C ↔ +85°C).