Smart materials, which can alter their shape or form in response to external stimuli, have become essential for applications ranging from medical devices to automotive industries. Now, a research team led by scientists from UC Santa Barbara and TU Dresden has taken this concept to the next level by creating a robotic collective that functions similarly to a smart material. This innovative collective is capable of changing its shape and transitioning between solid and fluid states, all while maintaining cohesion, supporting significant weight, and even demonstrating self-healing abilities.
The inspiration behind this groundbreaking development comes from the remarkable processes observed during embryonic development. During this phase, simple cells transform into complex tissues and organs through coordinated movement and shifts in mechanical properties. Prof. Otger Campàs, a co-author of the study, highlighted the significance of these processes: “Living embryonic tissues are the ultimate smart materials. To sculpt themselves, cells in embryos can make the tissues switch between fluid and solid states.” This unique ability of living cells to adapt their physical states served as the blueprint for the team’s robot collective.
The researchers identified three key biological processes in embryonic development that were crucial to replicating the fluidity and adaptability seen in living tissues: fluidization, polarization, and adhesion.
- Fluidization: Embryonic tissues can switch between a liquid-like and solid state due to internal cellular forces. This fluidity allows the cells to move past one another, as liquids do, while still maintaining a structural integrity that is characteristic of solids.
- Polarization: Embryonic cells are capable of aligning themselves in a specific direction, which enables directional forces to be applied. This is akin to organizing the cells so that they can move and rearrange in a controlled, purposeful way.
- Adhesion: Even as cells rearrange and move, they maintain strong connections with neighboring cells. This adhesion ensures that the tissue can reorganize into functional structures, like organs, while retaining its strength and stability.
These three principles became the foundation for the design of the robot collective that can change shape and structure, similar to how biological tissues develop.
The robot collective consists of individual robots that resemble circular discs, approximately five centimeters in diameter—akin to hockey pucks. Each robot is powered by an internal lithium-ion battery, providing up to 30 minutes of continuous operation. Eight gears are embedded along the robots’ perimeters, enabling them to push against one another and facilitate movement. Additionally, magnets located around the perimeter allow the robots to maintain adhesion with their neighbors, ensuring the collective remains intact as it reshapes.
To control the robots’ movements, each unit is equipped with a light sensor that includes polarized filters. This sensor detects the direction of incoming polarized light, which directs each robot on how to rotate its gears. Polarized light consists of light waves that vibrate in a specific direction, as opposed to unpolarized light, which moves in multiple directions.
Each robot is programmed to respond to two primary parameters: the direction of polarized light, which dictates the direction of movement, and the intensity of the light, which governs the force and extent of movement. This creates an “if-then” programming system: If light of a certain intensity and direction is detected, the robot knows exactly how to respond. The flexibility of this setup allows the researchers to guide the collective’s behavior without having to reprogram each robot individually for every desired shape or movement.
This technology opens up a world of possibilities. Just as biological cells can form tissues, organs, and systems, this robot collective can form complex shapes, adapt to changing environments, and even heal itself when parts of the system are damaged. These characteristics make the robot collective highly promising for use in diverse fields, including medical devices, aerospace, and disaster recovery, where adaptability, strength, and self-repairing capabilities are crucial.
By mimicking the biological processes that govern the growth and transformation of living organisms, this research demonstrates the potential for smart materials and robots to work in tandem, leading to innovations that blur the lines between organic and synthetic systems. The next steps for the team include refining the system for practical applications and scaling it up for larger, more complex projects.
In conclusion, this bio-inspired robot collective represents a leap forward in the field of smart materials and robotics, pushing the boundaries of what is possible in creating adaptive, self-healing systems capable of intricate and dynamic behavior.
By Impact Lab
