corobos: A Design for Mobile Robots Enabling Cooperative Transitions between Table and Wall Surfaces

Research Background and Problem

• Identified Problem or Challenge: Swarm User Interfaces (Swarm UIs) utilize a group of small mobile robots to enable dynamic user environment operations. However, their functionality is typically confined to a single plane, making it difficult to transition autonomously from a horizontal tabletop to a vertical wall. This limitation arises from the mobility mechanism based on two-wheel propulsion systems, which often require additional manual intervention or infrastructure (e.g., ramps) for support.
• Significance: Enabling these robots to autonomously transition between tables and walls could significantly expand the spatial applications of human-computer interaction, such as storing items on walls to free up desktop space or summoning additional robots from the wall to assist with tasks.
• Research Motivation and Related Work: Inspired by cooperative behaviors in nature (e.g., ant bridges), the authors aim to design a collaborative robotic system capable of autonomous transitions between tabletops and walls. This design addresses the inefficiencies and inflexibility of traditional methods (e.g., ramps or specialized structures).

Solution

• Proposed Solution: The authors present a prototype design—corobos, a two-wheeled mobile robot equipped with passive mechanical attachments. Through collaborative actions, these robots can achieve a 90-degree transition between a tabletop and a wall.
• Innovations:
  • Utilization of passive mechanical designs, eliminating the need for additional powered components, with attachments easily manufacturable via 3D printing.
  • Robots collaborate by applying thrust to complete the transition process without modifying the tabletop or wall environment.
  • Magnetic adhesion is employed to enhance wall mobility performance.
• Implementation Steps and Key Technologies:
  • Two-Part Attachment Design:
    • The "push" component facilitates the rotation of the transitioning robot.
    • The "ramp" component ensures smooth transition and adhesion under applied force.
  • Transition Mechanism Design:
    • Collaborative robot pushing adheres the transitioning robot to the wall and rotates it 90 degrees, with magnetic adhesion aiding wall attachment.
    • Gravity assists the transition from the wall back to the tabletop.
  • Experiments and Parameter Optimization:
    • Various ramp curvatures were designed and tested for transition stability.
    • A ramp curvature of n=1.3 demonstrated optimal performance in terms of transition force requirements and stability.

Research Outcomes

• Specific Results:
  • Corobos achieved efficient tabletop-to-wall transitions with a 100% success rate (n=1.3).
  • The robots can transport various items (e.g., keyboards or phones) and dynamically adapt to user scenarios.
  • Demonstrated applications include dynamic wall posting and educational use cases (e.g., teaching height concepts, interactive room layout simulations).
• Comparative Advantages Over Existing Solutions:
  • Traditional ramp methods occupy significant space and reduce user interaction flexibility, while the corobos design avoids these issues.
  • Similar magnetic robots cannot autonomously transition across complex surfaces, whereas corobos offers greater adaptability and functionality.
• Experimental and Evaluation Results:
  • Among different designs, the ramp curvature of n=1.3 enabled a tabletop-to-wall transition time of 0.53 seconds, showcasing higher efficiency and stability.
  • Payload tests indicated the robots could reliably carry up to 0.0076 N·m of torque (e.g., small to medium items like pens or LED lights).
• Limitations and Future Directions:
  • Transitions from walls to ceilings or between walls remain unachievable; future work will explore combining electromagnetic and permanent magnetic adhesion.
  • Safety concerns, such as the risk of robots falling, require further optimization, with plans to enhance material durability and component lifespan.
  • User studies are planned to gather feedback on user experience to further improve human-robot interaction and expand application scenarios.

Conclusion

Corobos introduces an innovative two-wheeled robot design that extends the spatial interaction range of Swarm UIs through a collaborative transition mechanism. By leveraging passive mechanical attachments and magnetic adhesion, this system opens new possibilities for complex user scenarios. Despite some current limitations, future work will focus on expanding surface interaction capabilities and enhancing user experience. The corobos design makes a significant contribution to spatial optimization and dynamic integration in Human-Robot Interaction.