Master Your Robotics Engineer Interview
Realistic questions, expert model answers, and a clear competency roadmap to boost your confidence.
- Cover technical, design, and behavioral topics
- Provide STAR‑based model answers
- Map each question to core robotics competencies
- Include tips, red‑flags, and follow‑up probes
Technical Knowledge
While developing a mobile robot for warehouse navigation, the team needed a controller for precise velocity tracking.
Select a control strategy that balances performance and computational load.
Described PID as a time‑domain, error‑based controller easy to implement and tune for single‑input single‑output systems. Explained LQR as a state‑space optimal controller that minimizes a quadratic cost function, requiring a model of the system dynamics. Compared tuning complexity, robustness, and suitability for multi‑variable systems.
Recommended PID for the low‑cost prototype due to simplicity, and LQR for the final product where a full dynamic model existed, resulting in smoother trajectories and reduced overshoot.
- How would you tune the PID gains for a robotic arm joint?
- Can you outline the steps to derive the state‑space model needed for LQR?
- Clarity of definitions
- Depth of comparison
- Use of concrete robotics examples
- Understanding of trade‑offs
- Vague statements without examples
- Confusing PID with PIDF or other variants
- Define PID (Proportional‑Integral‑Derivative) and its typical tuning parameters
- Define LQR (Linear‑Quadratic Regulator) and its reliance on state‑space models
- Contrast implementation complexity and computational requirements
- Discuss robustness and performance trade‑offs
- State scenarios where each controller is preferred
Designing a 6‑DOF cobot for assembly line assistance where safety and precision were critical.
Choose actuators that meet performance, safety, and cost requirements.
Identified torque and speed requirements, evaluated series‑elastic actuators for compliance, considered back‑drivable motors to reduce injury risk, reviewed encoder resolution for accurate positioning, and assessed thermal management and maintenance intervals.
Selected series‑elastic drives with integrated torque sensors, achieving safe interaction forces under 10 N while maintaining ±0.1 mm positioning accuracy, leading to successful pilot deployment.
- Why might you choose a pneumatic actuator over an electric one in a cobot?
- How do you validate the safety compliance of the chosen actuators?
- Identification of safety factors
- Link between performance specs and actuator choice
- Awareness of industry standards (e.g., ISO 10218)
- Ignoring human‑robot interaction safety
- Determine load, speed, and precision requirements
- Prioritize safety: compliance, back‑drivability, force limits
- Evaluate actuator types: servo, series‑elastic, pneumatic
- Consider integration aspects: control bandwidth, feedback sensors, thermal limits
System Design
Tasked with creating a navigation system for an autonomous forklift operating in a busy warehouse.
Develop a perception pipeline that reliably identifies pallets, static obstacles, and moving humans in real time.
Outlined sensor placement (mounted RGB‑D on mast), preprocessing (depth denoising, point‑cloud generation), object detection using a pretrained YOLOv5 model fine‑tuned on pallet images, obstacle segmentation via voxel‑grid clustering, and human detection using OpenPose on RGB frames. Integrated sensor fusion with Kalman filtering to track dynamic entities and generate occupancy maps.
Achieved 95 % pallet detection accuracy, sub‑0.2 m obstacle avoidance margin, and safe human‑robot interaction with a 0.5 s reaction time, enabling 20 % increase in throughput during pilot trials.
- How would you handle low‑light conditions for the RGB component?
- What fallback mechanisms would you implement if the depth sensor fails?
- Comprehensiveness of pipeline
- Justification of algorithm choices
- Real‑time performance considerations
- Safety and redundancy planning
- Overly generic pipeline without hardware constraints
- Sensor selection and mounting strategy
- Pre‑processing steps for depth data
- Object detection model choice and training
- Obstacle segmentation technique
- Human pose detection method
- Sensor fusion and tracking
- Generation of occupancy grid for navigation
Leading the control software for a fleet of inspection drones that operate in harsh industrial environments.
Ensure the system continues operating despite node failures or communication drops.
Proposed a micro‑service architecture with ROS2 DDS for reliable publish/subscribe, implemented health‑check heartbeats, used redundant master nodes with leader election (Raft algorithm), and added state replication via CRDTs. Designed fallback local controllers that can take over if the central planner is unreachable, and incorporated watchdog timers to reset faulty modules.
System maintained 99.8 % uptime over six months, with automatic failover handling 12 simulated node crashes without mission interruption.
- What metrics would you monitor to detect a degrading node before it fails?
- How does ROS2 improve fault tolerance compared to ROS1?
- Understanding of distributed systems concepts
- Specific fault‑tolerance mechanisms
- Scalability considerations
- Mentioning only single‑point‑of‑failure solutions
- Adopt a decentralized communication middleware (e.g., ROS2 DDS)
- Implement health monitoring and heartbeat mechanisms
- Use leader election and redundant master nodes
- Replicate critical state using CRDTs or consensus algorithms
- Provide local fallback controllers
- Integrate watchdog timers and safe‑stop procedures
Behavioral
During a product line upgrade, the mechanical team preferred upgrading existing PLC‑controlled stations, while the software team advocated for a new ROS‑based robot.
Secure approval for the ROS platform within a limited R&D budget.
Prepared a cost‑benefit analysis highlighting long‑term savings from modular software, demonstrated a rapid prototype that reduced cycle time by 30 %, and organized workshops to address concerns about training and integration.
Management approved a phased rollout, saving $150 k annually and delivering a 25 % increase in production speed within the first year.
- How did you measure the ROI of the new platform?
- What challenges did you face during the transition phase?
- Clarity of the story
- Evidence of influence and negotiation
- Quantitative impact
- Blaming others without personal contribution
- Identify stakeholder concerns
- Quantify benefits vs. costs
- Create a prototype or proof of concept
- Facilitate knowledge‑sharing sessions
- Present a phased implementation plan
While integrating a vision system into an autonomous guided vehicle (AGV), the camera firmware caused intermittent frame drops.
Deliver a reliable perception module on schedule.
Conducted root‑cause analysis, identified a driver incompatibility with the real‑time OS, collaborated with the vendor to release a patched driver, and implemented a fallback frame‑buffer strategy. Kept stakeholders informed with daily status updates and adjusted the project timeline for testing.
Stabilized the vision pipeline, met the launch deadline, and the AGV achieved 99.5 % detection reliability in field trials.
- What preventive measures did you put in place to avoid similar issues?
- How did you prioritize tasks during the crisis?
- Problem‑analysis depth
- Proactive communication
- Effective mitigation
- Lack of accountability
- Describe the setback clearly
- Explain diagnostic steps taken
- Detail collaboration with external parties
- Show timeline adjustments and communication
- Highlight the final outcome
- ROS
- PID control
- LQR
- sensor fusion
- SLAM
- C++
- Python
- embedded systems
- mechanical design
- project management