On the Stability of the Plane Movement of Mobile Robots with Walking Propulsion Devices Working in "Pulling" Mode

Abstract

Mobile robots with walking propulsion devices operating in a "pulling" mode, which, as a rule, are unstable, are considered. It is explained to the jamming of propulsion device due to the orthogonality of the acting force to the virtual displacement of the point of application. The task is to develop such an algorithm for controlling the robot, which consists in purposefully changing the geometric orientation of the propulsion devices controlled by the swing drive, which will ensure stable motion. A method for controlling the orientation of the walking plane with its initial deviation from the programmed position is proposed, based on the implementation of a discrete control algorithm, which provides for the introduction of such a piecewise constant function at each step of the mover, which has received an initial perturbation, which will provide a stable motion mode in a finite number of steps. The change in the orientation of the walking planes of the propellers connected with the steering is controlled, and thereby the direction of movement of the robot body changes in the first step, as in the subsequent ones. The described algorithm assumes the fulfillment of two necessary conditions: the presence of an information-measuring system that controls the orientation of the walking planes and ensuring that the interaction forces of the feet controlled by the steering of the propulsion devices with the supporting surface are sufficient for the absence of slippage. An algorithm for controlling "dependent" propulsion devices (working out the programmed translational motion of the body) is presented, taking into account the fact that their orientation depends on the orientation of the controlled ones, which consists in changing the step length, which should also be determined to ensure movement stability. The main task of controlling "dependent" propulsion devices, which do not change the orientation of their walking plane at the initial moment of time, is to determine the points for setting the feet by changing the step length, in accordance with the established criteria and design constraints, in particular, energy efficiency, maximum efforts in drives, maximum and minimum stride length. The propulsion device will start to work in a stable "pushing" mode at the final stage of motion correction, by performing a sequence of actions. It has been established that the "pulling" mode of the walking propulsion device can be stable, with appropriate control.