Zappa, a Quasi-Passive Biped Walking Robot With a Tail: Modeling, Behavior, and Kinematic Estimation Using Accelerometers

In this paper, we describe a biped mechanism model, as well as the biped robot Zappa based on it, that is able to walk using only one actuator that moves its tail. The model has 13 joints and 3 parallel link mechanisms that reduce the passive degrees of freedom to three. We present the behavior of this system when we vary the main parameters that define its gait, and the tail follows a chirp function. It represents an initial methodology for selecting an appropriate set of robot parameters. On the other hand, we present the biped robot Zappa and how we can estimate the kinematics during walking by means of using only three-axis accelerometers. This information allows the attainment of real phase diagrams and, in a future work, the estimation of the zero moment point from the positions and accelerations of the links of the robot.