Scientists in Spain have developed a robotic finger with a sense of touch. It is made of a polymer that can feel the weight of what it's pushing and adjust the energy it uses accordingly1.
This is similar to the way we use our sense of touch. If we pick up a delicate object such as a flower, our fingertips sense its fragility and so grasp it lightly. We instinctively exert more force when holding or moving a heavier, more robust item because there is feedback between our sensations and muscles.
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