Design of Track-Type Climbing Robots Using Dry Adhesives and Compliant Suspension for Scalable Payloads

Climbing robots offer advanced motion capabilities to perform inspection, manufacturing, or rescue tasks. Climbing requires the robot to generate adhering forces with the climbing surface. Dry adhesives present a category of adhesion that could be advantageous for climbing a variety of surfaces. Current literature shows climbing robots using dry adhesives typically exhibit minimal payloads and are considered useful for tasks involving lightweight sensors, such as surveillance. However, dry adhesives routinely demonstrate adhering pressures in the range of 20–50 kPa, suggesting that a small robot (3 × 30 cm footprint, for example) could theoretically have a significant payload (in the order of 18–45 kg). Existing designs demonstrate small payloads primarily because they fail to distribute the adhesion forces over the entire adhering region available to these robots. Further, existing design methods do not demonstrate scalability of payload-to-vehicle size but, in fact, indicate such robots are not scalable (Gorb et al., 2007, “Insects Did It First: A Micropatterned Adhesive Tape for Robotic Applications,” Bioinspir. Biomim., 2(4), pp. 117–125.). This paper presents a design procedure for track-type climbing robots that use dry adhesives to generate tractive forces and a passive suspension that distributes the climbing loads over the track in a preferred manner. This procedure simultaneously considers the behavior of both the adhesive material at the track-surface interface and the distribution of the adhesive forces over the full contact surface. The paper will demonstrate that dry-adhesive-based climbing robots can be designed to achieve high payloads and are scalable, thus enabling them to be used in applications previously thought to be impossible with dry adhesives.