Our muscles are nature’s perfect actuators — devices that turn energy into motion. For their size, muscle fibers are more powerful and precise than most synthetic actuators. They can even heal from damage and grow stronger with exercise.
Engineers are exploring ways to power robots with natural muscles, as they are more powerful and precise than synthetic actuators. They have created “biohybrid” robots that use muscle-based actuators to power artificial skeletons for various movements. However, there is no general blueprint for maximizing muscle performance in robot design.
MIT engineers have developed a spring-like device that can serve as a basic skeleton module for muscle-bound robots. This flexure design maximizes the movement produced by muscle tissues attached to it, allowing for more efficient use of muscle power.
The researchers found that the new flexure design allowed muscle tissues to stretch the spring five times more compared to previous designs. This flexure can be combined with others to create different configurations of artificial skeletons, which can then be powered by muscle tissues for movement.
Ritu Raman, an engineering professor at MIT, sees the flexure as a new building block for creating powerful and precise muscle-powered robots. The details of the flexure design are published in the journal Advanced Intelligent Systems.
When muscle tissue is left alone, it contracts in unpredictable directions. To use it as a mechanical actuator, engineers typically attach muscle tissue between flexible posts. However, this design produces limited movement due to the variability in how the muscle contacts the posts.
Raman’s group designed a skeleton that focuses and maximizes muscle contractions to generate predictable movement. They created a flexure that allows muscle force to be efficiently converted into motion in a specific direction.
The team collaborated with Professor Martin Culpepper to design a flexure that maximizes muscle stretching. This flexure is much softer than muscle tissue itself and enables focused contractions for maximum movement.
The researchers are now using flexures to build precise and reliable robots powered by natural muscles. They aim to create small robots, such as surgical robots, that can benefit from the strength, efficiency, and adaptability of biological actuators.
