Design and application of SMP adhesive pads for integration with wall climbing robots

• Main Author: Wu, Yao Zhong
• Other Authors: K Jimmy Hsia
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2024
• Subjects: Engineering
• Online Access: https://hdl.handle.net/10356/176571
• Institution: Nanyang Technological University

The increase in adoption of automation in various industries has highlighted the critical need for climbing robots, particularly to mitigate the inherent risks associated with human tasks at elevated heights. While current climbing robots predominantly rely on magnetic and negative pressure adhesion methods, inherent limitations, such as limited adaptability to various surface types, hinder their applicability across diverse industries. This study investigates the efficacy of using epoxy Shape Memory Polymers (SMP) as an alternative adhesion method for climbing robots, leveraging its distinct advantages, including strong load capabilities and good adaptability to various surfaces, over existing adhesives. However, the long response time of most frequently used thermally controlled SMP adhesion presents a significant drawback and limited its practical applications in industry. To address this challenge, this thesis proposes the integration of 3D embedded heaters and carbon nanotubes (CNTs) into epoxy SMP to expedite the adhesion process. Inspired by the uniform heat distribution mechanism employed in car rear windows, the proposed 3D embedded heaters utilize Joule heating to heat the adhesive tips precisely to enhance heating efficiency. The proposed 3D heaters were folded into the 3D forms from the 2D precursors, drawing inspiration from traditional Chinese Origami arts. Additionally, the introduction of CNTs into the epoxy SMP composite enhances thermal conductivity, further reducing response times. These innovations result in a remarkable reduction in response time from 4 minutes to 10 seconds, representing a 24-fold improvement. The adhesion strength for SMP with 10 % CNT content was tested to be about 1.9 MPa under the conditions of pre heating at 90 °C for 4 mins and cooling of 16 mins under a cooling fan, which was comparable to the results previously tested of pure SMP samples with the strength of about 1.89 MPa, proving that the introduction of CNT did not affect the adhesion strength. The integration of the new epoxy SMP adhesion method onto the Unitree Go1 Edu robotic dog was also explored. A specially designed foot pad incorporates strategically arranged 3D embedded heaters to ensure consistent heating, while a ball joint mechanism affords the robotic dog three degrees of freedom for manoeuvring uneven surfaces. A comprehensive control circuit, featuring four relays for adhesive foot control and a dedicated circuit board design, completing the integration process. This research underscores the transformative potential of epoxy SMP adhesion in climbing robotics, offering enhanced performance and versatility across a myriad of applications.