Waalbot: An Agile Small-Scale Wall-Climbing Robot Utilizing Dry Elastomer Adhesives

This paper proposes a small-scale agile wall-climbing robot, which is able to climb on smooth vertical surfaces using flat adhesive elastomer materials for attachment. Using two actuated legs with rotary motion and two passive revolute joints at each foot, this robot can climb and steer in any orientation. Due to its compact design, a high degree of miniaturization is possible. It has onboard power, computing, and wireless communication, which allow for semiautonomous operation. Various aspects of a functioning prototype design and performance are discussed in detail, including leg and foot design and gait dynamics. A model for the adhesion requirements and performance is developed and verified through experiments. Using an adhesive elastomer (Vytaflex 10), the current prototype can climb 90deg slopes at a speed of up to 6 cm/s and steer to any angle reliably on a smooth acrylic surface as well as transition from floor walking to wall climbing. This robot is intended for inspection and surveillance applications, and ultimately, for space missions.