Stability Analysis of a Wheel-Track-Leg Hybrid Mobile Robot

This paper proposes a new wheel-track-leg hybrid robot. The hybrid robot comprises a robot body, four driving mechanisms, four independent track devices, two supporting legs and one wheel lifting mechanism, which can fully benefit different advantages from wheeled, tracked and legged robots to adapt itself to varied landforms (the rough terrain and high obstacle). Based on the symmetrical mechanical structure, locomotion modes of the mobile robot are analyzed. With the coordinate transformation matrix, the center of mass of the robot is described. Moreover, the stability pyramid method is used to analyze on the climbing motion, especially in the hybrid locomotion mode. Through theoretical analysis, simulation and experimental verification, it’s proven that the robot can remain stable in the process of climbing motion.     

Magnebike: A magnetic wheeled robot with high mobility for inspecting complex‐shaped structures

This paper describes the Magnebike robot, a compact robot with two magnetic wheels in a motorbike arrangement, which is intended for inspecting the inner casing of ferromagnetic pipes with complex‐shaped structures. The locomotion concept is based on an adapted magnetic wheel unit integrating two lateral lever arms. These arms allow for slight lifting off the wheel in order to locally decrease the magnetic attraction force when passing concave edges, as well as laterally stabilizing the wheel unit. The robot has the main advantage of being compact (180 × 130 × 220 mm) and mechanically simple: it features only five active degrees of freedom (two driven wheels each equipped with an active lifter stabilizer and one steering unit). The paper presents in detail design and implementation issues that are specific to magnetic wheeled robots. Low‐level control functionalities are addressed because they are necessary to control the active system. The paper also focuses on characterizing and analyzing the implemented robot. The high mobility is shown through experimental results: the robot not only can climb vertical walls and follow circumferential paths inside pipe structures but it is also able to pass complex combinations of 90‐deg convex and concave ferromagnetic obstacles with almost any inclination regarding gravity. It requires only limited space to maneuver because turning on the spot around the rear wheel is possible. This high mobility enables the robot to access any location in the specified environment. Finally the paper analyzes the maximum payload for different types of environment complexities because this is a key feature for climbing robots and provides a security factor about the risk of falling and slipping. © 2009 Wiley Periodicals, Inc.     

Climbing Robots’ Mobility for Inspection and Maintenance of 3D Complex Environments

For complex climbing robots, which work in difficult 3D outdoor environments, the gravity force has an important influence with respect the robots changes during its motion. This type of climbing robots is self-supported in the complex 3D structures (bridges, skeleton of the buildings, etc.) which require periodic, manually performed inspections and maintenance. The use of non-conventional climbing robots for this type of operation is highly appropriate. Their locomotion system commonly comprises arms/legs that permit the robots 3D mobility (gait). These mechanisms also enable the robot to support itself and guarantee its stability. This paper presents the main features of non-conventional climbing robots mobility on complex 3D environments: power supply, number of DOFs, lightweight structure, gait, speed, secure grasp, etc. It also covers the general theory underlying the design of climbing robots, their kinematics, with its specific, unconventional mobility. The paper not only describes the climbing robot mobility theory but also provides several examples taken from the ROMA and MATS robots families. The developed robots have high degree of autonomy with totally on-board control system. These autonomous robots demonstrate in the course of real experimentation that the criteria for design, control strategy and path planning are accurate. Finally, the paper examines trends in climbing robot technology.Carlos Balaguer received his Ph.D. in Automation from the Polytechnic University of Madrid (UPM), Spain in 1983. From 1983–1994 he was with the Department of Systems Engineering and Automation of the UPM as Associated Professor. Since 1994, he has been a Full Professor of the Robotics Lab at the University Carlos III of Madrid. Prof. Balaguers research has included robot design and development, robot control, path & task planning, force-torque control, assistive and service robots, climbing robots, legged and humanoid robots, and human-robot interaction. He has published more than 120 papers in journals and conference proceedings, and several books in the field of robotics. He is a member of IEEE and IFAC, and former President of IAARC.Antonio Gimenez studied Electrical Engineering at the Polytechnic University of Madrid and received his PhD from the University Carlos III of Madrid in 2000. Currently he is Associated Professor at the Robotics Lab atthe University Carlos III of Madrid. He participated in numerous national and international R&D projects in robotics and automation. His research interest includes design and robot development, rehabilitation robots, climbing robots, and automation in construction. Recently he is very active in the field of computer-aided mechatronics design. He has published numerous refereed publications in international journals, and conference proceedings.Alberto Jardón Huete is currently finishing his Ph.D. degree in Automation Engineering. He received his B.Sc. in electronics engineering (1998) and is graduated in Electrical Engineering (2002) at University Carlos III of Madrid. He is an active member of the Robotics Lab since 1997, and has collaborated in the development of the climbing robots ROMA I, ROMA II, and other research projects of relevance. Currently he is focused in the design and development of light weight service robots. His interests include assistive robotic design, mechatronics, robotic research, the development of tools to perform this research and the transfer of robotics technology to industry.     

Design and analysis of a wall-climbing robot for passive adaptive movement on variable-curvature metal facades

To facilitate the safe adsorption and stable motion of robots on curved metal surfaces, a wall-climbing robot with a wheeled-type mobile mechanism that can passively self-adapt to walls with different curvature is proposed. The robot is composed of two relatively independent passive adaptive mobile mechanisms and overrunning permanent magnetic adsorption devices to achieve effective fitting of the driving wheels to the wall surface and adaptive surface motion. The overall design is based on a double-hinged connection scheme and gap-type permanent magnetic adsorption. The minimum adsorption force required for the robot to achieve stable climbing motion with no risk of slipping or capsizing is determined by developing a static analysis model. The effects of air-gap size and wall thickness on the adsorption force are analyzed by means of magnetic circuit design studies and parametric simulations on the permanent magnet adsorption device, as well as design optimization of the permanent magnet device. The motion performance test of the fabricated prototype shows that the robot can achieve adaptive curvature motion with self-attitude adjustment, and has a certain load capacity, obstacle crossing capability, and good surface adaptivity.     

Flat Dry Elastomer Adhesives as Attachment Materials for Climbing Robots

In this paper, flat elastomers are proposed as an attachment material for climbing robots on less than a few micrometer-scale rough surfaces due to their energy-efficient, quiet, and residue-free characteristics. The proper elastomer is chosen by the use of the current adhesion, friction, and peeling elastomer-contact-mechanics models. Then, adhesion and friction properties of the chosen dry flat-elastomer thick films (Vytaflex-10) are characterized on acrylic and smooth and rough glass surfaces for variations in preloads, speeds, contact times, and elastomer thicknesses. A climbing robot with four-bar-based legged-body kinematics is designed and fabricated as simple and lightweight as possible to demonstrate the feasibility of the elastomers as attachment materials on relatively smooth surfaces. The robot utilizes a passive alignment system to make the footpads parallel to the surface on light contact, a peeling mechanism to minimize the detachment vibration, and a passive tail to minimize the pitch-back moment. Experimental results showed that the robot can climb stably on vertical, smooth surfaces in any direction and can walk inverted for a limited amount of time.      

Climbing robots for maintenance and inspections of vertical structures—A survey of design aspects and technologies

The maintenance and inspection of large vertical structures with autonomous systems is still an unsolved problem. A large number of different robots exist which are able to navigate on buildings, ship hulls or other human-made structures. But, most of these systems are limited to special situations or applications. This paper deals with different locomotion and adhesion methods for climbing robots and presents characteristics, challenges and applications for these systems. Based on a given set of requirements these principles are examined and in terms of a comprehensive state-of-the-art more than hundred climbing robots are presented. Finally, this schematics is applied to design aspects of a wall-climbing robot which should be able to inspect large concrete buildings.     

Design and control of a climbing robot based on hot melt adhesion

Robust climbing in unstructured environments has been one of the long-standing challenges in robotics research. Among others, the control of large adhesion forces is still an important problem that significantly restricts the locomotion performance of climbing robots. The main contribution of this paper is to propose a novel approach to autonomous robot climbing which makes use of hot melt adhesion (HMA). The HMA material is known as an economical solution to achieve large adhesion forces, which can be varied by controlling the material temperature. For locomotion on both inclined and vertical walls, this paper investigates the basic characteristics of HMA material, and proposes a design and control of a climbing robot that uses the HMA material for attaching and detaching its body to the environment. The robot is equipped with servomotors and thermal control units to actively vary the temperature of the material, and the coordination of these components enables the robot to walk against the gravitational forces even with a relatively large body weight. A real-world platform is used to demonstrate locomotion on a vertical wall, and the experimental result shows the feasibility and overall performances of this approach.     

拆线机器人的轮式爬线机构及顶升装置设计

拆线施工机器人是一种爬线机器人,挂在架空线上沿线行进,代替工人完成拆线施工中索道缆绳的铺设。为满足拆线施工机器人在具有一定垂弧度的架空线上爬线行进的需要,对拆线施工机器人的爬线行进机构进行了分析与设计,提出了一种四轮爬线行进机构。该机构利用顶升装置及张紧轮提供额外的压力,以满足拆线施工机器人爬坡时所需的摩擦力。随后,分析了机器人爬坡时的受力情况,给出了顶升装置所提供压力的条件及计算公式。基于所提机构,进行了施工机器人的顶升装置的选型计算及论证,实际应用表明本文的设计可以满足实际需要。     

A new simulation based robot command library applied to three robots

A new type of high‐level robot command library is presented and demonstrated. Three robot programming languages have been analyzed and new robot command libraries created for three types of robot. The programming of three robots using the new high‐level robot command library demonstrated that it was possible to program robots with different kinematic configurations without the programmer having any knowledge of the physical structure of the robots. The library commands contained simulations of the abilities of the robots as well as having the ability to control the physical robots. This paper shows how simulation can be incorporated into a high‐level robot command library and how the command library can be used for the programming of three industrial robots. ©1999 John Wiley & Sons, Inc.     

Design and motion planning of an autonomous climbing robot with claws

This paper presents the design of a novel robot capable of climbing on vertical and rough surfaces, such as stucco walls. Termed CLIBO (claw inspired robot), the robot can remain in position for a long period of time. Such a capability offers important civilian and military advantages such as surveillance, observation, search and rescue and even for entertainment and games. The robot’s kinematics and motion, is a combination between mimicking a technique commonly used in rock climbing using four limbs to climb and a method used by cats to climb on trees with their claws. It uses four legs, each with four-degrees-of-freedom (4-DOF) and specially designed claws attached to each leg that enable it to maneuver itself up the wall and to move in any direction. At the tip of each leg is a gripping device made of 12 fishing hooks and aligned in such a way that each hook can move independently on the wall’s surface. This design has the advantage of not requiring a tail-like structure that would press against the surface to balance its weight. A locomotion algorithm was developed to provide the robot with an autonomous capability for climbing along the pre-designed route. The algorithm takes into account the kinematics of the robot and the contact forces applied on the foot pads. In addition, the design provides the robot with the ability to review its gripping strength in order to achieve and maintain a high degree of reliability in its attachment to the wall. An experimental robot was built to validate the model and its motion algorithm. Experiments demonstrate the high reliability of the special gripping device and the efficiency of the motion planning algorithm.     

Formation tracker design of multiple mobile robots with wheel perturbations: adaptive output-feedback approach

This paper presents a theoretical design approach for output-feedback formation tracking of multiple mobile robots under wheel perturbations. It is assumed that these perturbations are unknown and the linear and angular velocities of the robots are unmeasurable. First, adaptive state observers for estimating unmeasurable velocities of the robots are developed under the robots’ kinematics and dynamics including wheel perturbation effects. Then, we derive a virtual-structure-based formation tracker scheme according to the observer dynamic surface design procedure. The main difficulty of the output-feedback control design is to manage the coupling problems between unmeasurable velocities and unknown wheel perturbation effects. These problems are avoided by using the adaptive technique and the function approximation property based on fuzzy logic systems. From the Lyapunov stability analysis, it is shown that point tracking errors of each robot and synchronisation errors for the desired formation converge to an adjustable neighbourhood of the origin, while all signals in the controlled closed-loop system are semiglobally uniformly ultimately bounded.     

基于Netvlad神经网络的变磁力吸附爬壁机器人控制系统设计

变磁力吸附爬壁机器人是一种具有快速、灵活移动方式的爬行机器人,但其吸附力难以控制,越障稳定性较差,难以保证机器人的平稳爬行;为实现爬壁机器人在大型建筑结构外表面的自主避障,提升机器人与运动平面之间的吸附紧密性,设计基于Netvlad神经网络的变磁力吸附爬壁机器人控制系统;按照PCB控制要求,连接外置SRAM设备与传感器模块,借助驱动I/O口电路提供的电力驱动作用,控制气动阀门的闭合情况,完成变磁力吸附爬壁机器人控制系统硬件结构设计;建立Netvlad神经网络体系,通过划分控制指令程序任务的方式,确定移植参数取值范围,实现对控制协议的移植处理,联合相关硬件应用结构,完成基于Netvlad神经网络的变磁力吸附爬壁机器人控制系统设计;实验结果表明,在所设计系统作用下,障碍物所在位置与爬壁机器人所在位置之间的实测距离未大于30cm,能够有效实现自主避障,保证机器人与运动平面之间的紧密吸附。     

基于DSP技术的爬壁机器人吸附控制系统设计

壁面吸附是爬壁机器人的基本功能之一,其吸附程度直接影响爬壁机器人的稳定性和移动速度;为此,设计了基于DSP技术的爬壁机器人吸附控制系统;选择爬壁机器人传感器装置,加设DSP数字信号处理器,设计爬壁机器人吸附控制器;在硬件结构的支持下,根据爬壁机器人的组成结构和工作原理,构建相应的数学模型;在该模型下,利用DSP技术计算爬壁机器人吸附力;通过爬壁机器人在壁面环境下的受力分析结果,确定爬壁机器人安全吸附条件;以吸附控制器作为执行机构,实现爬壁机器人的吸附控制;选择负压爬壁机器人作为测试样机,通过系统测试表明,在瓷砖、木板、玻璃三种壁面环境下,与两个对比系统相比,应用此次设计系统得出爬壁机器人吸附力的控制误差降低了2.04 N,倾覆风险系数降低了0.29,具有较好的吸附控制效果。     

A heterogeneous modular robotic design for fast response to a diversity of tasks

This paper describes a heterogeneous modular robot system design which attempts to give a quick solution to a diversity of tasks. The approach is based on the use of an inventory of three types of modules i.e., power and control module, joint module and specialized module. Each module type aims to balance versatility and functionality. Their design permits rapid and cost effective design and fabrication. They are interchangeable in different ways to form different robot or system configurations. Depending on the task, the operator decides what type of robot can provide the best performance within the mission. A spherical joint module is described and used to build different robots, hence, forward and inverse kinematics models are obtained. Finally, from the modules described in this work, several robot configurations such as robotic arms, leg-based robots and wheel-based robots are assembled to demonstrate the execution of manipulation and locomotion tasks.     

Motion planning for tree climbing with inchworm‐like robots

This paper proposes a global path‐ and motion‐planning algorithm that enables inchworm‐like robots to navigate their way up tree branches. The intuitive climbing space representation method proposed here greatly simplifies the path‐planning problem. The dynamic programming algorithm can be used to identify the optimal path leading to the target position in the target direction according to the constraints and requirements specified. The planned path can be applied in any tree‐climbing robot that utilizes the nonenclosure gripping method. An efficient motion‐planning algorithm for continuum inchworm‐like robots is then developed to enable them to climb along the planned path with a high degree of accuracy. In comparison with the method proposed in our previous study, the method proposed herein significantly improves consistency between the planned path and the motions of the robot, and therefore makes it more practical to implement the motion‐planning algorithm in trees of different shapes. The paper also describes hardware experiments in which the proposed planning algorithm is applied to enable inchworm‐like robots to climb real trees, thus validating the proposed planning algorithm in practice. © 2012 Wiley Periodicals, Inc.     

A comprehensive review on deploying robotics application in telecom network tower's field maintenance: Challenges with current practices and feasibility analysis for robotics implementation

This survey article highlights the difficulties in the field maintenance of telecommunication towers. It critically analyses the main features of the deployment of robots to maintain telecommunication towers. The growing demand for mobile connectivity poses the need for more towers, and the subsequent problem of network maintenance becomes more critical. Most tower maintenance is required work at height; therefore, height-related risks are more frequent. A rigorous review is conducted, and the growth of the telecommunications network and key on-site maintenance challenges are analyzed. Despite numerous challenges, these towers are maintained manually by riggers (certified climbers) worldwide. It raises the question, Is it possible to implement automation by robots for the maintenance of telecommunications towers? The feasibility analysis to deploy the robots is conducted systematically. To access the tower through a robot, detailed information on the type of towers, the climbing arrangements available on the existing towers, and the necessary operations to be carried out at the height is collected. A critical analysis of the climbing robots currently available in the literature, their grasping technology, and control algorithms is performed. The opinion of experts in the telecommunication industry is very helpful in identifying the requirements of robotic systems. The design attributes especially needed for the climbing robot, and the execution of the maintenance in height are highlighted. Due justification is given for deploying robots for field maintenance of telecom towers. The recommended methodology for designing an automation system helps research in the field of maintenance of telecom towers through robots, which could bring a remarkable solution to the telecom sector.     

The OmniTread OT‐4 serpentine robot—design and performance

Serpentine robots are slender, multi‐segmented vehicles designed to provide greater mobility than conventional mobile robots. Serpentine robots are ideally suited for urban search and rescue, military intelligence gathering, and inspection tasks in hazardous or inaccessible environments. One such serpentine robot, developed at the University of Michigan, is the “OmniTread OT‐4.” The OT‐4 comprises seven segments, which are linked to each other by six joints. The OT‐4 can climb over obstacles that are much higher than the robot itself, propel itself inside pipes of different diameters, and traverse difficult terrain, such as rocks or the rubble of a collapsed structure. The foremost and unique design characteristic of the OT‐4 is the use of pneumatic bellows to actuate the joints. The pneumatic bellows allow the simultaneous control of position and stiffness for each joint. Controllable stiffness is important in serpentine robots, which require stiff joints to cross gaps and compliant joints to conform to rough terrain for effective propulsion. Another unique feature of the OmniTread design is the coverage of all four sides of each segment with drive tracks. This design makes the robot indifferent to rollovers, which are bound to happen when the slender bodies of serpentine robots travel over rugged terrain. This paper describes the OmniTread concept and some of its technical features in some detail. In the Experiment Results Section, photographs of successful obstacle traverses illustrate the abilities of the OT‐4. © 2007 Wiley Periodicals, Inc.     

考虑高速公路横向坡道转向行驶操纵稳定性的汽车轴距和轮距分析

为分析汽车轴距和轮距设计对操纵稳定性的影响,建立高速公路横向坡道转向行驶的汽车转向动力学模型,并在MATLAB/Simulink软件中建立相应的仿真模型.采用某型汽车设计轴距和轮距进行仿真,得到以不同速度在不同横向坡度道路上转向行驶时的横摆角速度、侧向加速度和质心侧偏角.根据该型汽车的转向特性和侧翻阈值评价其在高速公路...     

EJBot-II: an optimized skid-steering propeller-type climbing robot with transition mechanism

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.     

Development of universal vacuum gripper for wall-climbing robot

Task performed at a height, such as wall inspections are one of the dangerous tasks for humans. Thus, robotic technology for safety inspection is required. This research focuses on developing robots to climb vertical walls with flat and uneven surfaces, e.g. concrete, tile and riveted structure. To have wall-climbing capability, climbing robots use vacuum pads, claws, magnets, intermolecular force, and adhesive. However, each of these approaches has disadvantages. To achieve wall climbing on an uneven surface without scratching and staining, we have developed a novel vacuum pad named the Universal Vacuum Gripper (UVG), which is based on the Universal Gripper (UG). The UG is a robot hand using jamming transition of coffee powder inside a balloon to grip uneven material. The UVG is a vacuum pad with a deformable skirt based on the UG. If the skirt shape is deformed in accordance with the contact surface, air leaks can be avoided. Moreover, the deformed skirt can be stiffened, thereby working as a gripper. Here, we evaluate the proposed gripper, having both grasping and adhesion force. We also develop a wall-climbing robot with UVGs, and evaluate its performance on uneven surfaces under real-world conditions.