The invention belongs to the field of robots, and discloses a compliant
robot based on change of stress of circumferential elastic pieces, which comprises an upper platform, a first
variable stiffness module, a
variable stiffness joint, a second
variable stiffness module and a lower platform, a circumferential elastic piece in the second variable-rigidity module is fixed by a supporting column and is equivalent to a free
cantilever beam, the position of a second sliding
assembly on the circumferential elastic piece is changed, so that the circumferential elastic piece is stressed to deform, variable rigidity is achieved, and large output torque is achieved; the Archimedes spiral plate rotates to enable the first connecting rod to do
linear motion, so that variable rigidity is realized; rapid displacement of the second sliding
assembly is achieved through the stepping motor, the first synchronous belt wheel, the second synchronous belt wheel and the
bevel gear set, rapid displacement of the first sliding
assembly is achieved through the Archimedes spiral plate, and response is rapid; different rigidity characteristics and output torques can be obtained by adopting circumferential elastic sheets with different elasticity or
bevel gear sets with different moduli, so that different rigidity characteristic requirements are met; the method is used for achieving
robot flexible driving.