Design and Development of the I.T.U. Biped Robot

Abstract

This paper presents the design and construction of a 12-DoF biped walking robot. Thekinematics of electrically actuated 6-DoF legs is similar to that of human legs with three DoF atthe hip, one at the knee and two at the ankle joints. The mechanical design of the robot wasbased on dynamical simulations realized in a modular PC environment. Two communicatingsoftware were used in order to solve the forward dynamics of the system and to design walkingcontrollers. Forward, backward and lateral walking as well as stair climbing behaviors with upto 6 km/h forward walking speeds have been simulated in order to determine the nominal powerrates required at joints. Hip joints are actuated by DC motors coupled to harmonic reducerssituated both in joint axes. The actuators driving the knee and ankle joints are situated higherthan the respective joint axes and the rotational output motion of DC motors are transmitted tothe joints through linear ball-screw mechanisms. Spherical joints are used within thetransmission of spatial motion required for the 2-DoF at ankle joints. All joints consist ofabsolute encoders and 6-axes force/torque transducers are mounted at the ankle joints. The robotis controlled through an embedded industrial PC running real-time operating system. Allelectronic control hardware including the motor drivers and sensors communicate through CANbus. The robot’s mass without batteries is 55 kg and its height is 142 cm.