9.17. Human-Robot Interaction (HRI)

9.17.1 Collaborative Robots (Cobots)

• Designed to work safely alongside humans.
• Equipped with:
  • Force-limiting sensors
  • Soft end-effectors
  • Smart stop/recovery logic

Collaborative robots, often referred to as cobots, are specifically designed to interact safely with human operators in various work environments. These robots have several safety features, including:

• Force-limiting sensors: These sensors detect when the robot exerts too much force during operation, which helps to prevent injuries if a human comes into contact with the robot.
• Soft end-effectors: Their grippers and tools are designed to be gentle and flexible, minimizing the risk of harm when in proximity to humans.
• Smart stop/recovery logic: This feature allows the robot to stop instantly if it detects unexpected obstacles, such as a human entering its working path, and safely resume its task once the pathway is clear. Together, these technologies enable robots to work efficiently while prioritizing human safety.

Imagine a factory where cobots are assembling products on the same line as human workers. Just like a trained dog that can respond to its owner's commands and stay out of the way when needed, cobots are programmed to operate around humans without risk of injury. If a worker accidentally bumps into the robot, the cobot instantly stops and re-evaluates its environment before continuing its task, similar to how a dog might pause and regroup after being called.

9.17.2 Modes of Interaction

• Hand-guiding: Operator physically moves robot to desired position.
• Gesture and Voice Commands
• Augmented Reality (AR) Interfaces

Human-robot interaction can occur in several intuitive and effective ways:

• Hand-guiding: This method involves a human operator physically guiding the robot to a specific location. This is particularly useful for teaching the robot tasks or adjusting its work directly.
• Gesture and voice commands: Operators can use natural gestures or verbal instructions to communicate with robots. For instance, an operator might wave a hand or say 'lift' to make the robot perform a related action, making the interaction easier and more fluid.
• Augmented Reality (AR) interfaces: These interactive platforms overlay digital information onto the physical world. Through specialized glasses or screens, operators can visualize robot tasks, view instructions, or receive feedback in real-time, greatly enhancing the user's experience and interaction with the robot.

Think of a child learning to fly a kite. The child can guide the kite with their hands, feel how it responds to the wind, shout instructions to a friend helping them, or even use a special kite-flying app that shows tips and tricks on their smartphone. Similarly, operators can direct cobots by physically guiding them, giving voice commands, or checking instructions through AR, making the process smoother and more efficient.

9.17.3 Use Cases in Civil Engineering

• Bricklaying cobots
• On-site layout marking robots
• Human-supervised rebar tying systems

In civil engineering, human-robot interaction is leveraged to enhance productivity and safety through various applications:

• Bricklaying cobots: These robots assist or handle the placement of bricks, ensuring consistent quality and speed, while allowing human workers to focus on oversight and complex decision-making.
• On-site layout marking robots: These automate the process of marking out designs or layouts directly on construction sites, greatly reducing errors and saving time.
• Human-supervised rebar tying systems: Here, robots assist in the tying of rebar in construction, working under the supervision of human operators to ensure safety and quality control. The combination of robots and human expertise leads to a more efficient workflow and improved project outputs.

Picture a sports team where each player has a specific role, such as a quarterback calling the plays or a lineman blocking for their teammates. In civil engineering, human workers team up with robots like a quarterback and their supportive team, leveraging the strengths of both—the robots provide efficiency and precision while humans oversee tasks and make critical decisions on the job site.

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