Vacuum Control in the Surface Attaching Devices of the Mobile Robots during their Movement under the Aerodynamic Attachment Force

Abstract

During the movement of the horizon mobile robots over different complex ferromagnetic and non-ferromagnetic surfaces, like walls, ceilings or slopes of various angles, their contacts with the surfaces can be realized by the attaching devices, which ensure an aerodynamic attachment force due to creation of vacuum. In industrial robotics such devices are designed for grasping objects with manipulators on the assembly lines. In the mobile robotics such devices are suitable for creation of an attachment force for the robots. The control system provides an aerodynamic attachment force due to control of the pressure level inside the vacuum area. This ensures adaptation for the mobile robots moving over the surfaces with different quality parameters. This paper describes creation of vacuum with a centrifugal pump and a turbine. It also presents an attachment device based on a centrifugal pump or a turbine, which can create an aerodynamic attachment force for movement of a mobile robot over the sloped surfaces. The air pressure inside the turbine depends on the shape of the blades, the air density and the circumferential speed of the blades. The air pressure created by the centrifugal pump or the turbine is proportional to the blades' rotary speed squared. The dependence of the air pressure on the air flow is obtained. This ensures calculation of the attachment force for the control system of a mobile robot. Simultaneous solving of the equations presented in this paper for the air pressure and the air flow provides an opportunity to obtain the operating modes for different types of the vacuum devices based on a centrifugal pump or a turbine. A possibility of the aerodynamic attachment force control by varying of the gap between the mobile robot and the surface is analyzed. Various parameters of air, such as density, average velocity and flow rate, are discussed. Creation of vacuum inside the vacuum area is considered. The experimental results concerning the pressure control, the attachment force and vacuum creation are presented.