In Star Wars: Return of the Jedi, Wicket W. Warrick is an Ewok.
Wicket is a small, furry sentient inhabitant of the forest moon of Endor. He encounters Princess Leia after she lands on Endor and helps bring her to the Ewok village. Later, he and other Ewoks participate in the battle against the Imperial forces protecting the second Death Star.
Ewoks are not robots, but their primitive-looking tools and camouflage can make them seem like mechanical characters at a glance. The question identifies Wicket specifically because he is sometimes confused with droids or other small Star Wars species, especially Jawas.
Warwick Davis played Wicket while wearing the character costume. The Ewoks' role in the film is important because their knowledge of Endor's terrain helps the Rebel ground team fight the Empire.