A Novel Propeller–Type Climbing Robot for Vessels Inspection Mohamed G. Alkalla a , Mohamed A. Fanni b and Abdelfatah M. Mohamed c Abstract— This paper is proposing and designing a novel propeller–type climbing robot for exploring the interiors of industrial vessels and enables a human outside it to implement required regular inspection tasks efficiently. There are two main adhesion systems in the literature: magnetic and air suction systems. The magnetic system climbs surfaces made of ferromagnetic materials only, while air suction system can handle neither irregular surfaces due to possible seal damage nor cylindrical surfaces. Opposite to previous climbing robots, the proposed robot here can climb and navigate vessels made from different materials besides handling possible irregular or cylindrical surfaces. Its main task is visual inspection of welds and any critical spots inside these vessels. The novelty of this robot comes from utilizing a hybrid actuation system consists of upturned propellers fixed on mobile robot with motorized wheels. The pressure generated from the upturned propellers increases the friction force between the wheels of the mobile robot and the wall. The wheels’ motors generate the required torque either to fix the robot at any position or to move it to any place. Since the motion of the robot comes mainly from the motorized wheel, the stability of the system during navigation is guaranteed. Simulation and control results of the designed robot using ADAMS and Matlab softwares prove the success and feasibility of the robot concept. I. INTRODUCTION The systems which have a capability of climbing vertical structures or navigate inside tanks and vessels have an in- creasing importance in the last two decades. The application fields of the climbing robots are ranging from welding of ship hulls to the inspection of steel bridge or nuclear power plants. Common systems such as ‘Rest’ which uses six legs and magnetic pads for climbing [1], are applied for such tasks. It is realized that such climbing systems are mainly adopted in places which cannot be reached by humans, where the direct access for the human is too expensive and dangerous. Almost all climbing robots are depending on two main systems (locomotion and adhesion system) to keep the robot attached to the vertical structures. The climbing robot needs to be designed based on the desired functions and field of applications and these aspects define which locomotion and adhesion principle are needed. There are many locomotion principles such as wheels [2], tracks [3], sliding frames [4], arms and legs [5]. Each locomotion system depends on the nature of the surface which these Mohamed G. Alkalla is Ph. D. Student, Mohamed A. Fanni is Associate Professor and Abdelfatah Mohamed is Professor at Mechatronics and Robotics Engineering Department, School of Innovative Design Engineer- ing, Egypt-Japan University of Science and Technology (E-JUST), New Borg El-Arab, Alexandria, PO Box: 21934, Egypt. (a,b) on leave: Pro- duction Eng. and Mechanical Design Dept., Faculty of Engineering, Man- soura University, Egypt. (c) on leave: Electrical Engineering Department, Faculty of Engineering, Assiut University, Egypt. E-mail:{mohamed.gouda, mohamed.fanni, abdelfatah.mohamed}@ejust.edu.eg. robots are moving on and each one has an advantage over the others at certain requirements, see [6]. There are many adhesion systems such as magnetic, pneumatic, mechanical, electrostatic and chemical adhesion systems. The last two adhesion systems are less common than the others. The magnetic adhesion system depends on the magnetic force between robot and the vertical structure. It is used only for the ferromagnetic material structures. Some climbing robots make use of this adhesion system such as REST robot [1]. The second common type of adhesion system is a pneumatic system which depends on air suction, and the attraction force between the robot and the wall is proportional to the pressure difference between the pressure chamber or suction cup and the atmosphere. There are a lot of climbing robots make use of this principle such as CROMSCI, which combines an omni-directional drive system with an adhesion system equipped with a seven-chamber adhesion system [7]. This pneumatic adhesion type is used for flat and even surfaces. The third common adhesion system uses mechanical gripers and claws and it is suitable for the rough surfaces, such as RISE robot [8]. Some new but less common approaches for adhesion which arise with the material science are electrostatic principle which generate electrostatic or Van der Waals forces between the surface and the robot, such as STICKYBOT [9] and chemical adhesion which uses thermal glue or sticky tapes as [10]. A simple survey on the common climbing robots is presented in [6]. II. THE PROPOSED CLIMBING ROBOT A novel climbing robot is proposed here which can overcome a lot of difficulties that faced previous climbing robots such as: Is the vessel material ferrous or not? Is the surface even or not? These aspects will not be a problem in this proposed robot design, since it depends on upturned propellers mounted on a mobile robot. This idea is opposite to flying concept. The propellers are supposed to push and generate normal force against the vessel wall. Consequently, it does not need a ferrous structure like magnetic adhesion robots, flat/regular surfaces like suction chambers robots, or rough surfaces for grippers like mechanical adhesion robots. A propellers system is previously used only for driving a climbing robot as presented in [11] and [12]. This system used inclined propellers not only to move the robot forward but also to stick it to the wall during motion, as shown in Fig. 1. Also there was no steering system for this robot where passive wheels are used. So, the robot can’t turn left or right. Moreover, the navigation stability was a major problem in this robot, as mentioned in [6]. The proposed idea here is based on a hybrid actuation system which utilizes both 2015 IEEE International Conference on Advanced Intelligent Mechatronics (AIM) July 7-11, 2015. Busan, Korea 978-1-4673-9107-8/15/$31.00 ©2015 IEEE 1623