Design and analysis of a biphasic variable impedance actuator

Variable impedance actuators guarantee control performance for robots and robotic peripherals that are inherently safe to humans in their environment especially in cooperative tasks involving human-robot interaction. This paper presents a concept of variable impedance actuator using a combination of fluid and gas to realize the adaptation of the impedance. For this actuator, the ranges of variation of the impedance are studied with different initial conditions and positions of the piston in the actuator; The dynamic response characteristic is analyzed in presence of a variable external load. A method of control of the actuator is proposed and the performance shown while performing a testing cycle