Omnidirectional locomotion and traction control of the wheel-driven, wall-climbing robot, Cromsci

Abstract

Safe and cost-efficient inspection of large concrete buildings is a great challenge for mobile robots. This paper presents the locomotion system of the climbing robot, CROMSCI, which uses three steerable standard wheels and negative pressure adhesion. We will introduce criteria to avoid robot slip and tilt, and methods to enhance stability. One elementary part is the close-loop-controlled adhesion system with seven individual negative pressure chambers to balance out tilt or dynamic effects caused by leaky pressure chambers. The second part is the locomotion control using a special traction control mechanism to enhance robot navigation, which will also be presented here.

Advanced Motion Control for Safe Navigation of an Omnidirectional Wall-Climbing Robot

“…To test the benefit of the traction control system the robot moves upwards a wall with immediate accelerations. It already has been proven that the robot is able to drive up to eight times further with activated TCS compared to test runs with disabled traction control [SHB11]. Regarding navigation safety, figure 4 shows the ratio of sideward forces F W 1|xy to the absolute downforce F W 1|z of the front wheel.…”

“…An overview concerning different traction control systems applied at automobiles can be found at [Bur93]. But based on the present system setup, a novel slip reduction technique has been developed which uses measured forces at the wheel contact point [SHB11] since classic approaches are not suitable in this special context. In a physical sense a loss of traction is the result of too low friction force compared to affecting lateral and tangential forces at the contact point between wall and wheel as in general describe in terms of a friction circle.…”

“…Finally, the integral value I Wi|v,I of the PI motor velocity controller has to be adapted during limitation of the motor current to avoid further increases of the integral portion [SHB11]. The controller setup is illustrated in figure 2.…”

“…For communication purposes and energy supply it is connected to a ground station via an umbilical cord. The unique feature of CROMSCI is the negative pressure system consisting of seven individual adhesion chambers in a shape of spokes which allows a balancing of downforces [SHB11]. Three suction engines evacuate a vacuum reservoir on top which is connected via valves to the adhesion chambers at the undercarriage.…”

Prototype Design and Experimental Test of a Rotorcraft Capable of Adhering to and Moving on the Ceiling

“…In addition, the fundamental limitation of a UAV is that, it cannot access the ceiling surface of bridge structure or a building. For this reason, robots having the capability of adhering to the ceiling or wall has got an attention from the robotics research society [6][7][8][9][10]. So far, their fundamental limitation is that they can move only on the face of the wall, and cannot fly in the air.…”