On the Formation and Accuracy of the Implementation of the Program Modes of Movement of Mobile Robots with Walking Propulsion Devices

Abstract

   Various kinematic schemes of walking propulsion devices of mobile robots are considered. Among them there are cyclical mechanisms with a different number of links, zoomorphic, insectomorphic, orthogonal and others. Propulsion devices may differ from each other in the number of drives. Examples of walking machines and laboratory samples with such propulsion devices are given. The importance and significance of the tasks of ensuring the accuracy of positioning the foot of the propulsion device as the working body of the walking mechanism, due to the need to place it on the supporting surface at a given point when moving the propulsion device, are substantiated. It is also necessary to overcome obstacles identified by the information-measuring system and having certain dimensions and located in certain places on the support surface. Such a movement should be accompanied by a minimum of the height of the foot lift, which ensures a minimum of energy consumption. Additionally, the necessity of ensuring the required speed of the foot of the propulsion devices walking mechanism in the phase of its interaction with the support surface is justified, which is explained by maintaining the same speeds of the support feet in the relative heading movement in the phase of the implementation of the traction force. Even with a slight difference in the speeds of the support stops, the traction force is developed only by the propulsion device, whose foot moves at maximum speed. The remaining propulsion devices operate in braking mode. Compensation is possible only due to the rigidity of the static characteristics of the engine and the viscous-elastic-plastic properties of the soil. In this case, an increased load is imposed on the drive motors and therefore energy efficiency is reduced. The problem of assessing the accuracy of positioning is solved by known methods by introducing the transfer functions of the stepping mechanism. The transfer functions link the movement of the output element of the motor of the corresponding drive and the working body of the walking mechanism — the foot. To solve the problem of estimating the accuracy of the walking mechanism by the speed of the foot, new transfer functions are introduced, which are components of the new matrix. Their characteristic feature is the dependence on the speeds of the output elements of the executive motors. The equation of motion providing optimality in positioning accuracy and speed is obtained.