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Important steps forward in the creation of artificial muscles for soft-robots

A material made of silicone and ethanol, printed in 3D, allows the creation of a soft synthetic muscle that represents a fundamental element for the creation of autonomous soft robots.

A group of researchers at Columbia Engineering has made a significant step forward in the creation of soft-robots capable of actions and movements similar to those performed by living beings, realizing – for now in the laboratory – a soft synthetic muscle using 3D printing techniques.

The particular artificial fabric, made by a group of Creative Machines Lab coordinated by the mechanical engineering professor Hod Lipson, is active and has expansion and contraction capabilities that do not require an external device such as a compressor or a high-voltage system that are normally used for this type of structures.

The material has an expansion per gram higher than 15 times to a biological muscle and has the ability to lift up to 1000 times its weight.

The existing technologies that somehow replace the force exerted by a muscle are based on the hydraulic or pneumatic inflating of elastomeric membranes. This requires external accessory devices that hinder the miniaturization and construction of robots capable of moving and operating independently.

The researchers used a silicone rubber mesh with ethanol distributed in micro bubbles. These materials make it possible to realize an actuator with elastic properties and volume variations that are normally obtainable with other material systems, maintaining ease of construction, low-cost and respecting the environment.

The artificial muscle, after having been 3D printed in the desired shape, is activated electrically with a thin resistive cable and with a voltage of 8V. Tested in various robotic applications, it showed the ability to expand up to 900% when electrically heated to 80°C.

Researchers will now continue to develop the system on three fronts: integration of conductive materials, reduction of response time and extension of useful life. As a longer-term perspective, the use of artificial intelligence techniques for the management and control of muscles is envisaged, a phase that could represent the last obstacle to overcome before being able to replicate the natural movement.

” We have made remarkable strides in the realization of the minds and brains of the robots, but the bodies are still primitive. This is a big piece of the puzzle and as with living beings, the new actuators can be formed in thousands of ways. We have overcome one of the final barriers to creating life-like robots, ” said Lipson.

Robotics based on soft materials is very important for those areas where robots will have to interact with humans. Unlike robots based on rigid structures and elements, soft robots have the ability to replicate natural movements to offer assistance of various types, perform actions with delicacy or grasp fragile objects.