King Abdulaziz City for Sciece and Technology, Saudi Arabia
Climbing robots are special mobile robots which can move and work vertically on working targets to carry out specific tasks. They have a special working environment and use mobility against gravity. Especially in the recent 15 years, there has been considerable progress in walking and climbing robotic research worldwide by exploring the potential applications in hazardous and unmanned environments. Typical applications include reliable non-destructive evaluation (NDE) and diagnosis in hazardous environments, welding and manipulation especially of metallic structures in the construction industry, and maintenance of high-rise buildings.
Many climbing robots use legged structures with two to eight legs, where more limbs inherently provide redundant support while walking and increase the load capacity and safety. Robots with multiple-leg kinematics are complex due to several degrees of freedom. These robots, which use vacuum suckers and grasping grippers to attach to surfaces, are big, heavy and complex. Thus, in situations where compactness and efficiency are critical, a structure with minimal weight and complexity is preferred. As the simplest kinematic model in this class, bipeds vary most significantly in the style of their middle joints. Robots by Nishi, the robot ROBIN, and the robot RAMR1 use a revolute middle joint. A prismatic middle joint is used by ROSTAM IV, whereas the robot by Yano does not have a middle joint but simply a rigid central body. ROSTAM IV, the smallest robot in this class built to date, weighs approximately 4 kg. But its movements are neither reliable enough nor safe enough. Generally, the adhering and releasing movements of the attachment procedure are actuated separately. Also, in order to move continuously, some legs have to be released from the wall with only a few legs remaining attached to it, which makes the robot less safe.
The sliding frame is a special kinematic structure adopted by climbing robots which is not suitable for designing a flexible mobile prototype. The structure usually includes two frames which slide along the movement axes to realise linear movement. A company in Japan developed a climbing robot for cleaning the embassy of Canada which, however, cannot walk sideways. Generally, all of these robots are very large and the size and weight of these prototypes is the main disadvantage for real application in complex working environment.
Compared to similar climbing robots, the goal of this proposal is to develop a flexible, small mobile robotic platform with two units connected by a flexbile joint, featuring an easy-to-build mechanical structure, a safety protecting mechanism when the climbing robot is falling down, and a negative attachment principle for urban search and rescue application. The climbing robot will have various locomotion capabilities including climbing on different materials, moving between two surfaces that stand at various angles, crossing and avoiding obstacles and gaps, and roaming a 3D workspace. The performance of the proposaed robot is shown in Table I. The robot could also be used as a climbing platform for monitoring, searching, and other possible applications.
- Urban search and rescue
- Civil exploration and searching
- Reliable non-destructive evaluation and diagnosis in hazardous environments
Previous research and publications
- Houxiang Zhang, Jianwei Zhang, Wei Wang: From the biological model to a small climbing caterpillar robot, International Journal Advanced Mechatronic Systems, Vol. 2, No. 1/2, pp.90-98, 2010.
- Houxiang Zhang, Wei Wang, Juan Gonzalez-Gomez, Jianwei Zhang: Design and Realization of a Novel Modular Climbing Caterpillar Using Low-frequency Vibrating Passive Suckers, Advanced Robotics, Vol.23, pp.889-906, 2009.
- Houxiang Zhang, Jianwei Zhang, Wei Wang, Rong Liu, Guanghua Zong: A Series of Pneumatics Glass-wall Cleaning Robots for High-rise Buildings, Industrial Robot: An International Journal, Vol.34, No.2, 2007, pp.150-160.
- Houxiang Zhang, Jianwei Zhang, Wei Wang, Rong Liu, Guanghua Zong: Sky Cleaner -A Real Pneumatic Climbing Robot for Glass-Wall Cleaning, IEEE Robotic & Automation Magazine, Vol.13, No.1,2006, pp.32-41.
- Houxiang Zhang, Jianwei Zhang, Rong Liu, Guanghua Zong: Realization of a service robot for cleaning spherical surfaces, International Journal of Advanced Robotic Systems, Vol.2 No.1, 2005, pp.53-58.