On the detachment from the ground of the walking locomotor’s foot of the mobile underwater robot

Abstract

A special feature of mobile robots in general and walking in particular, moving along the bottom of reservoirs is the specific conditions of their movement. This is manifested in the action of the pushing force, the possible presence of a flow, an increased resistance to movement due to a more dense (compared to air) environment, a «compression» effect. The problem of the de-tachment of the foot of a mobile robot with walking locomotors from the ground was studied. The relevance of the problem is determined due to a number of advantages of using walking locomotor over other types of locomotors, on the one hand, and the need to reduce efforts in locomotors’ drivers on the other. A mathematical model has been developed for the separation of a locomotor’s foot from the ground, based on Henry's laws establishing the concentration of dissolved air in a liquid, the law of gas expansion at a constant temperature, Darcy's law on fluid filtration and the theorem on the motion of the center of mass of a solid body. The linearized model also allows obtaining analytical solutions. Direct and inverse problems are formulated, which differ in the fact that in one case the equation of the foot motion is defined and the force acting on it is determined, and in the othercase, the nature of the foot motion is established. The obtained results qualitatively correspond to the known experimental data. The established pat-terns make it possible to set tasks for the purposeful control of normal reactions acting on the feet of walking locomotors of underwater mobile robots or cargo of anchor-cable actuators through the use of structures that allow adjusting the permeability coefficient of the bottom soil through which the liquid is filtered.