Analysis and design of a minimalist step climbing robot

In this article, a novel yet simple step climbing robot is proposed and is comprised of two front wheels, a rear-wheel and an actuator to vary the center distance between the front and rear wheels. When a robot climbs a stair, the huge variance in the inclination angle of the robot may result in its toppling. Hence, a mechanism is proposed to compensate for the change in inclination angle. An inertial measuring unit (IMU) is used to sense the inclination angle of the robot which is then fed to a microcontroller in order to actuate the connecting link, thereby reducing the variation of the inclination angle. During ascending simulations on dynamic model based on the Newton–Euler formulation, the required torque on rear wheel is reduced by 26.3% as compared to uncontrolled simulations. Moreover, the normal reaction on rear wheel during descending simulation has increased by 170.9% by controlling the inclination angle, which reduced the probability of toppling of the proposed robot. Multiple experiments on the prototype with a controlled condition show that the variation in inclination angle is reduced by 77.8% during ascending, whereas it is reduced by 92.8% during descending resulting in successful operation on the stairs as compared to uncontrolled cases.