Constrained convergent gait regulation for a climbing robot

The priorities of a climbing legged robot are to maintain a grasp on its climbing surface and to climb efficiently against the force of gravity. These priorities profoundly constrain the choice of gait regulation methods. We propose a gait regulation and analysis method that varies foot detachment timing, effectively modifying stride length and frequency in order to maintain gait phasing, subject to kinematic and stability constraints. The method results in linear equations, leading to straightforward tests for local and global convergence when, for example, disturbances such as foot slippage cause departures from the nominal phasing. We illustrate the procedure with an example involving a bounding gait and compare it with empirical results obtained on the RiSE climbing robot.