Mahmoud Tavakoli

A hybrid pole climbing and manipulating robot with minimum DOFs for construction and service applications

Purpose – Aims to describe design, prototyping and characteristics of a pole climbing/manipulating robot with ability of passing bends and branches of the pole.Design/methodology/approach – Introducing a hybrid (parallel/serial) four degree of freedom (DOF) mechanism as the main part of the robot and also introduces a unique gripper design for pole climbing robots.Findings – Finds that a robot, with the ability of climbing and manipulating on poles with bends and branches, needs at least 4 DOFs. Also an electrical cylinder is a good option for climbing robots and has some advantages over pneumatic or hydraulic cylinders.Research limitations/implications – The robot is semi‐industrial size. Design and manufacturing of an industrial size robot are a good suggestion for future works.Practical implications – With some changes on the gripper module and the last tool module, the robot is able to do some service works like pipe testing, pipe/pole cleaning, light bulb changing in highways etc.Originality/value – ...

OmniClimbers: Omni-directional magnetic wheeled climbing robots for inspection of ferromagnetic structures

This paper introduces Omniclimber, a new climbing robot with high maneuverability for inspection of ferromagnetic flat and convex human made structures. In addition to maneuverability, adaptability to various structures with different curvatures and materials are addressed. The conceptual and detailed design of OmniClimbers are presented and two prototypes of the robot are introduced. Several laboratory and field tests are reported, and the results are discussed.

3DCLIMBER: A climbing robot for inspection of 3D human made structures

3DCLIMBER is a running project in the University of Coimbra for developing a climbing robot with the capability of manipulating over 3D human-made structures. This paper mainly discuss the conceptual and detailed design and development of a Pole Climbing robot with minimum degrees of freedom which can climb over 3D structures with bends and branches followed by Preliminary test results of the robot performance. Electronics architecture and control algorithms are briefly described. The paper finishes with discussion of the current results and identifies some future works.

Development of an industrial pipeline inspection robot

Purpose – The purpose of this paper is to describe design and development of a pole climbing robot (PCR) for inspection of industrial size pipelines. Nowadays, non‐destructive testing (NDT) methods are performed by dextrous technicians across high‐level pipes, frequently carrying dangerous chemicals. This paper reports development of a PCR that can perform in situ manipulation for NDT tests.Design/methodology/approach – Introduces a PCR including a novel four‐degrees of freedom climbing serial mechanism with the nearly optimal workspace and weight, unique V‐shaped grippers and a fast rotational mechanism around the pole axis. Simplicity, safety, minimum weight, and manipulability were concerned in the design process.Findings – The developed prototype proved possibility of application of PCRs for NDT inspection on elevated structures. Design and development of PCRs which are able to pass bends and T‐junctions faces much more difficulties than those which should climb from a straight pole.Practical implicat...

Adaptive under-actuated anthropomorphic hand: ISR-SoftHand

ISR-Softhand is a novel under-actuated self contained anthropomorphic robotic hand which takes advantage of elastic joints and soft pads. The integrated compliance in the hands joint allows for a very good adaptability to a wide range of objects. It can achieve the top ten grasps with highest frequency of usage by humans, with only three actuators.

Design and Prototyping of a Hybrid Pole Climbing and Manipulating Robot with Minimum DOFs for Construction and Service Applications

In this paper, conception, design, modeling, and prototyping of a multi-task 4 DOF pole climbing/manipulating robot are discussed. The hybrid serial/parallel mechanism, with 2 translations and 2 rotations provides a good solution for a pole climbing and manipulating robot which can travel along tubular structures with bends, branches and step changes in cross section. It is also able to perform manipulation, repair and maintenance tasks after reaching the target point on the structure. After discussing conceptions of the mechanism, modeling and some aspects of the detailed design are presented. Then some of the issues with the prototyping of the robot mechanism are discussed.

OmniClimber: An omnidirectional light weight climbing robot with flexibility to adapt to non-flat surfaces

This paper introduces a novel climbing robot with high maneuverability for inspection of ferromagnetic 3D human made structures. The robot takes advantage of novelties which allows an excellent maneuverability on the structure and can adapt to flat and non-flat structures. In this paper we present the conceptual and detailed design of the robot, the implementation and two tests: laboratory tests on a flat surface; and a set of field tests performed on a wind turbine foundation to prove the applicability of the robot on both structures.

Underactuated anthropomorphic hands

This paper aims to analyze the number of actuators as well as the actuation strategy for underactuated prosthetic hands. Two comprehensive analyses were performed for this purpose. 16 possible actuation strategies in five categories of one to five actuators were defined. Based on these 16 strategies two analyses were performed: grasp diversity and grasp functionality. In the first analysis, we defined a performance metric based on all possible grasps by the human hand, while in the second analysis only the top grasps with the highest frequency of usage were considered. By comparing the performance of these strategies we obtained some interesting results regarding the best actuation strategies for the under-actuated anthropomorphic hands. Such study can be useful for designers in the early stages of designing a prosthetic terminal, for deciding the number of actuators and how such actuators are allocated to the DOFs of the hand. In other words, this study shows which joints of the hands should be coupled together and driven by a single actuator, in order to get the best performance with minimum number of actuators. This is important for developing hands, which have a small number of actuators (i.e. less than 5 actuators), and thus benefit from a simple electromechanical structure. Actuation Strategies for Under-actuated Anthropomorphic Hands.Sixteen actuation strategies in five groups (1-5 actuators).2 benchmarks for grasp diversity and grasp functionality.2 comprehensive analyses for each criteria.Suggestions for design of efficient under-actuated hands with minimum actuators.

Cooperative multi-agent mapping of three-dimensional structures for pipeline inspection applications

This article proposes two methods based on cooperation between climbing and ground robots in order to address the mapping problem for autonomous inspection of three-dimensional (3D) structures. A pole climbing robot was developed to autonomously inspect a 3D human-made structure. The robot is able to climb over 3D human-made structures with bends and T-junctions. In the previous version of the system, the robot operator had to provide a set of data, resembling the map of the 3D structure, to the path planning algorithm of the climbing robot. However, the necessity of a priori knowledge of the structure’s geometry reduces the autonomy of the system. In this article we propose two solutions in which the structure in front of the robot is mapped autonomously. In the first proposed method, ground robots act as a mobile observer with a wide coverage for a climbing robot, to detect and estimate the size of the structure being climbed. We will present a case study in which multiple terrain robots provide the model of a structure which should be explored by a pole climbing robot. Each terrain robot is equipped with a low-cost wide angle Visual Graphics Array (VGA) camera, and some markers are fixed on the climbing robot. At each navigation step, the climbing robot and terrain robots cooperate to model a part of the structure which should be explored by the climbing robot. We also present a second approach in which a depth image from a Microsoft Kinect (a motion sensing input device by Microsoft) is fused with the information from the camera in order to eliminate the dependency of the system on color and light conditions.

Single channel surface EMG control of advanced prosthetic hands

A single channel surface EMG can be used to detect up to 4 hand gestures.This can be done by a fast support vector machine classification approach.With this system, advanced prosthetic hands can be controlled with a simple HMI.Calibration time is less than 30s and classification time is less than 0.3s. Surface EMGs have been the primary sources for control of prosthetic hands due to their comfort and naturalness. The recent advances in the development of the prosthetic hands with many degrees of freedom and many actuators, requires many EMG channels to take the full advantage of the complex prosthetic terminals. Some EMG wearable devices were developed lately, that are able to detect several gestures. However, the main drawbacks of these systems are the cost, the size and the system complexity. In this paper, we suggest a simple, fast and low-cost system which can recognize up to 4 gestures with a single channel surface EMG signal. Gestures include hand closing, hand opening, wrist flexion and double wrist flexion. These gestures can be used to control a prosthetic terminal based on predefined grasp postures. We show that by using a high-dimensional feature space, together with a support vector machine algorithm, it is possible to classify these four gestures. Overall, the system showed satisfactory results in terms of classification accuracy, real time gesture recognition, and tolerance to hand movements through integration of a lock gesture. Calibration took only 30 seconds and session independence was demonstrated by high classification accuracy on different test sessions without repeating the calibration. As a case study we use this system to control a previously developed soft prosthetic hand. This is particularly interesting because we show that a simple hardware that has only a single channel EMG, can afford the control of a multi-DOF prosthetic hands. In addition, such system may be used as a general purpose Human Machine Interface for gaming,for controlling multimedia devices, or to control robots.