Dr Mohamed Alkalla

This paper presents a new kind of climbing robots called EJBot, which has not been restricted to climb certain surface materials or terrains. EJBot is inspired by propeller-based aviation systems, however, its adhesion principle is opposite to flight concept. Thanks to the hybrid actuation system embedded in this robot which gives a good and stable adhesion. This hybrid system consists of propeller thrust forces and wheel torques actuated simultaneously to generate the proper adhesion force. It is similar to a car climbing a ramp, it needs both weight of the car and the wheels' torques. Without these torques, the car will roll down. Consequently, the thrust forces of the propellers increase the traction force capacity, then the wheels' role arises to generate the convenient torques for stopping the robot or navigating it on the structures. The feasibility of this adhesion concept is verified by the first and second modules of EJBot as presented in the simulation and practical results.

Most robotic applications demand lightweight and high-speed manipulators for considerably reducing the consumed power and achieving high production rates. The two ways for seeking such high-speed arms are; applying advanced control algorithms and/or performing an extensive optimization of the arm structure itself. Therefore, the topology optimization technique is proposed here for obtaining an optimal robot arm design from both structure and control viewpoints. Results of some researches, that have been previously accomplished by size and shape optimization, were encouraging enough to extend and propose this optimization approach. The method of moving asymptotes (MMA) as an optimization algorithm, the finite element analysis (FEA) by ANSYS, and the time-optimal control method are integrated to gain an optimum design capable of attaining the minimum traveling time. The proposed methodology focuses on performing different comparisons between the proposed optimum topological designs and their initial designs for different robot arms’ sizes and materials. It also distinguishes between the proposed optimum design and the previously achieved one by size optimization under the same operational conditions. Therefore, the significance of the proposed technique is emphasized. It shows that the traveling time is reduced by 44.8%, while the previous work only achieved 23.5%. In addition, the mass is reduced to nearly half of its initial value, taking into account the air damping as the real case in all terrestrial applications.

As massive scientific information is trapped inside the geologic formation of planetary bodies, the objectives of most exploration missions mainly involve sampling, in-situ testing and analyzing of the cutting's formation for seeking any sign of primitive life or resources. This can be accomplished by subsurface exploration by specific drilling techniques which entail challenges that are apparently more complex than drilling on the earth. One of these challenges is the low-gravity that should be compensated by the over-head mass of the drilling system. This excessive mass represents a burden during launching the mission. Therefore, it is necessary to choose an energy-efficient and light-weight drilling system capable of reaching high depths. This article focuses on optimizing drill bit geometry (i.e., profiles, cross-sections, and teeth) of the bio-inspired wood-wasp drill for targeting new potential depths into the Martian regolith and reducing its drilling time. Different morphological designs of the drill bit are generated and experimentally tested for their drilling feasibility into a fine and coarse-grain Martian regolith. A Comparison between old and new proposed drill bits is presented, based on drilling time, consumed power, and slope of depth-time curve. The proposed designs show a significant reduction of the drilling time between 20% to 56.5% over the old one, while the required over-head mass (OHM) and power to penetrate 760mm depth is only 3kg and 45 watts, respectively. This practical work reveals the necessity of getting customizable drill bits for each single location of the extraterrestrial surfaces even on Moon or Mars based on its unique character which can be categorized as soft and hard formulations.

EJBot is a propeller-type skid steering climbing robot (SSCR) based on both thruster and differentiable driving systems. Its adhesion principle utilizes a simultaneous hybrid actuation system consisting of propeller thrust forces and driving wheel torques. EJBot can climb different kinds of surfaces, moreover, exploring the industrial vessels’ interiors for implementing the inspection tasks efficiently. kinematics and dynamics analysis are presented in this article for EJBot as an SSCR. The experimental results validate the theoretical findings and ensure the stability of the robot’s adhesion and navigation systems. The robot can cross over significant obstacles with 40 mm height.

Topology optimization approach is considered among the most interesting fields of structural optimization. In this paper topology optimization for compliance minimization using method of moving asymptotes MMA is presented. This method is considered as a general and flexible optimization method, where it can handle any kind of objective function and any number of constraints. The effect of changing the lower and upper asymptotes on the optimization process convergence is studied for seeking the demanded convergence with more stability and minimum time as possible. Topology optimization of different models such as a cantilever beam and simply supported beam for two and three dimensional structure is accomplished. Also a comparison between Method of Moving Asymptotes (MMA) and different methods such as Sequential Quadratic Programming (SQP), Optimality Criteria (OC), and Hybrid Cellular Automata (HCA) is made according to the compliance value, time consumed and the resulted topological shape.

This work focuses on proposing and designing a new climbing robot to explore the interiors of industrial vessels and enables a human outside the vessels 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 cannot handle irregular surfaces due to possible seals damage. Opposite to previous climbing robots, the proposed robot here can climb and navigate vessels made from different materials besides handling possible irregular surfaces during inspection. 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. This hybrid actuation system consists of upturned propellers fixed on mobile robot and motorized wheels of the mobile robot. The pressure generated from the upturned propellers increase 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 in 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. Size and topology optimizations are carried out to achieve optimum design of the proposed robot. Simulation results of the designed robot using ADAMS software prove its feasibility.

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.

The purpose of this paper is to propose a new propeller-type climbing robot called EJBot for climbing various types of structures that include significant obstacles, besides inspection of industrial vessels made of various materials, including non-ferromagnetic material. The inspection includes capturing images for important spots and measuring the wall thickness. The design mainly consists of two coaxial upturned propellers mounted on a mobile robot with four standard wheels. A new hybrid actuation system that consists of propeller thrust forces and standard wheel torques is considered as the adhesion system for this climbing robot. This system generates the required adhesion force to support the robot on the climbed surfaces. Dynamic simulation using ADAMS is performed and ensures the success of this idea. Experimental tests to check the EJBot’s capabilities of climbing different surfaces, such as smooth, rough, flat and cylindrical surfaces like the real vessel, are successfully carried out. In addition, the robot stops accurately on the climbed surface at any desired location for inspection purposes, and it overcomes significant obstacles up to 40 mm. This proposed climbing robot is needed for petrochemical and liquid gas vessels, where a regular inspection of the welds and the wall thickness is required. The interaction between the human and these vessels is dangerous and not healthy due to the harmful environment inside these vessels. This robot utilizes propeller thrusts and wheel torques simultaneously to generate adhesion and traction forces. Therefore, a versatile robot able to climb different kinds of structures is obtained.