Autonomous Wall-climbing Robots for Inspection and Maintenance of Concrete Bridges (AS-3)

University: The City College of New York

Principal Investigator: Dr. Jizhong Xiao, The City College of New York

PI Contact Information: Phone: (212) 650-7268  |  Email:

Co-Principal Investigators: Dr. Anil Agrawal, The City College of New York
                                                        Dr. Hung La, University of Nevada, Reno

Funding Sourcesand Amounts Provided:
CCNY In-Kind Match: $190,322
INSPIRE UTC: $180,193

Total Project Cost: $370,515

Match Agencies ID or Contract Number:
CCNY: In-Kind Match   |   INSPIRE UTC: 00055082-01A

INSPIRE Grant Award Number: 69A3551747126

Start Date: March 1, 2017
End Date:  December 31, 2018

Brief Description of Research Project:

Since 2002, the PI’s group has developed four generations of wall-climbing robots for NDE inspection of civil infrastructure. These robots combine the advantages of aerodynamic attraction and suction to achieve a desirable balance of strong adhesion and high mobility. They don’t require perfect sealing and can thus move on smooth and rough surfaces, such as brick, concrete, stucco, wood, glass, and metal. For example, Rise-Rover uses two drive modules to carry their middle compartment with payload up to 450 N. GPR-Rover and Mini GPR-Rover are custom designed to carry a GSSI’s GPR antenna for subsurface defect detection and utility survey on concrete structures such as bridges and tunnels. The robots can also carry other devices such as impact echo and ultrasonic flaw detectors for bridge evaluation. To date, all the robots are remotely controlled to scan concrete surfaces.

Approach and Methodology: Even available, GPS signals cannot accurately pinpoint the location of subsurface flaws. Therefore, a fast visual odometry method is proposed to estimate the pose and trajectory of a robot and in turn locate and mark the flaws. Features between consecutive images taken with a camera are detected and matched, and then fused with IMU (inertia measurement unit) data to achieve accurate motion control and feature registration/mapping. With this method, a robot with a camera can carry NDE devices, reach hard-to-access areas, take close-up pictures, scan the surfaces of bridge columns, girders, and decks (both top and bottom sides), record and wireless send NDE data to a host computer, log GPS coordinates, and record subsurface defect locations with respect to local landmarks at every sampling point for visualization and analysis. A robot can also be augmented with mechanisms and tools to perform maintenance actions such as cleaning, painting, and repairing.

Overall Objectives: This project aims to develop motion control and localization methods to make wall-climbing robots a fully autonomous system with automated inspection process using various NDE devices and sensors, and design innovative mechanisms and tools and integrate them into the robots for maintenance actions.

Scope of Work in Year 1:  (1) Design an embedded controller for GPR-Rover and develop methods to eliminate the potential interference between GPR signal and robot circuit, (2) Develop accurate motion control and localization methods that enable the robot to track grid patterns and take NDE samples automatically, (3) Design a spray painting mechanism to mark defects, and (4) Evaluate the integrated robotic inspection system and the localization method using a GPR and a camera.

Scope of Work in Year 2: (1) Develop a new robot with multiple chambers to overcome the limitation when a single-chamber robot crosses over deep gaps, and (2) Field test the new robot with a GPR antenna to scan hard-to-access places, take close-up pictures, sample and transmit GPR data back to a host computer for further analysis.

Describe Implementation of Research Outcomes:
Research outcomes and implementation plan will be described towards the end of this project.

Impacts/Benefits of Implementation:
Impact/Benefits of Implementation will be summarized at the end of this project.

Project Website:
Progress Reports: