EJBot-II: Skid-Steering Propeller-Type Climbing Robot

Why Climbing Robots, Such as EJBot-II, Are the Future (and the Coolest)

Imagine a world where robots effortlessly climb skyscrapers, inspect the toughest spots on nuclear plants, and rescue those in danger from high places. These robots are becoming a reality, and at this rate of advancement, we will be witnessing various cool climbing robots in the near future that are able to solve real-world problems in places where human involvement is too risky.

One such robot is EJBot-II. This robot has the potential to carry out many different tasks, from cleaning those impossible-to-reach glass facades to inspecting the intricate welds of ships, tanks, and bridges. But EJBot-II is currently designed to traverse the outer and inner surfaces of vessels in petrochemical and liquefied gas industries, conducting wireless visual inspections of welds for corrosion and measuring wall thickness.

What Makes EJBot-II Special for Climbing?

When you think of propellers, you might think of drones and helicopters using them to move away from the surface. But EJBot-II leverages propeller-based aviation systems with an intriguing twist—to stay on the surface. It uses a hybrid actuation system (wheels and propellers) to ensure that the climbing robot doesn't fall off the surface while it moves around walls, ceilings, and curved surfaces securely.

Think of a car on a steep ramp: the car relies on both its weight and the torque of its wheels to avoid rolling back. Similarly, EJBot-II's propellers increase traction force (similar to the weight of a car on a ramp), while the wheels provide the torque and friction needed to navigate and stop on inclined surfaces.

The Magic of the Propeller System

The main benefit of using a propeller-based climbing method is that, unlike other climbing adhesion systems such as suction cups and magnets, it eliminates the need for smooth surfaces or a particular structural material. Thus, holes, cracks, protrusions, and even curvatures on cylindrical surfaces are no issue for this robot. This versatility opens up many possibilities for operating in complex environments such as vessels, pipes, and bridges.

A Closer Look at EJBot-II's Ingenious Design

The original version, EJBot-I, already had an impressive design that featured two coaxial upturned propellers on a mobile platform with four wheels. But EJBot-II takes it up a notch. The wheels have been swapped out for a track system, providing superior traction. Plus, EJBot-II is built with a composite material frame, making it both stiff and lightweight.

Another great upgrade of EJBot-II is the mechanism to smoothly transition from the ground to a vertical wall. Several transition mechanisms were investigated but the two-arm design underneath the robot was found to be the most suitable option. The two arms beneath the robot generate forces against the ground, effortlessly lifting the robot towards vertical surfaces.

And let's not forget the batteries—now mounted directly on the robot, there's no more dealing with the cumbersome and heavy umbilical cord that hinders the movement of the robot.