https://www.mdpi.com/2218-6581/5/3/14/pdf

A Survey of Wall Climbing Robots: Recent Advances and Challenges

\n Magnetic adsorption mechanisms are widely used for wall-climbing robots to manipulate a locomotive on the surface of a magnetic conducting metal. However, the reported magnetic adsorption mechanisms are subject to the problems such as the lack of adsorption capability, the weakness of kinematic performance, and the overwhelming detaching force. To solve the problems, a novel style of a permanent-magnetic adsorption mechanism using an electromagnetic method and internal force compensation principle is detailed in this work. Specifically, a permanent magnet, an electromagnet, and a nonlinear spring are configurated to achieve a reliable adsorption function by using the minimal detaching force. Following that, the results obtained from both the finite element analysis and the experiments carried out by using a prototype demonstrated its effectiveness. It does not only have a rapid and controllable adsorption-detachment capacity in reference to the magnetic conducting surface but also has low power consumption, large adsorption force, and reliable and safe performance.

A Novel Style Design of a Permanent-Magnetic Adsorption Mechanism for a Wall-Climbing Robot

Nature has developed multi-functional geometric structures, and surface textures with excellent tribological characteristics, such as feet of geckos. Geckos have extraordinary abilities to climb walls and even upside down on the ceiling. Studies have revealed that hierarchical structure of gecko’s feet can bear the weight of two humans and this strong adhesion force is mainly generated by weak van der Waals force. This paper reviews the mechanisms and the forces responsible for gecko’s adhesion, and the effect of humidity on adhesion against different hydrophobic/hydrophilic surfaces. The excellent adhesive and frictional properties of gecko adhesion system have inspired many researchers to develop gecko-inspired synthetic adhesives. In this paper, recent development of gecko-inspired synthetic adhesives has been presented in terms of various fabrication methods, different tip structures, and the effect of counter surface roughness as well as design criteria to avoid bunching of nano-structures. The application of synthetic adhesives is also discussed for wall climbing robots and novel applications in the field of space, biomedical and sports accessories.

Natural Adhesion System Leads to Synthetic Adhesives

Climbing control of autonomous mobile robot with estimation of wheel slip and wheel-ground contact angle

One of the key factors that affect the efficiency and scope of work of wall-climbing robots is how the climbing robot can achieve autonomous transition between adjacent vertical planes. This paper studies the problem of ground-wall transition of a self-developed suctorial wall-climbing hexapod robot (WelCH). In view of the feasibility of the robot performing transition, this paper makes a detailed analysis of the number and property of degrees of freedom (DOFs) of the body and the foot based on reciprocal screw theory, and the results show that the robot can achieve transitional motion only when its home configuration is axisymmetric rather than radially symmetric. For realizing the robot’s ground-wall transition, based on a Sinusoid-Sigmoid-Shaped (SS-Shaped) interpolation function, the motion strategies of foot transferring and body pitching are firstly designed in detail. This interpolation method can effectively avoid the wear of the suction cups by relying on fewer essential path points. Then, the saturation-truncated method and mean filtering method are used to deal with joint constraints and abrupt changes in angular velocities. Finally, a kinematic-based adaptive sliding mode control (ASMC) is adapted to track the planned smooth trajectory, which can effectively resist bounded external disturbances. The successful transitions from the horizontal ground to the vertical wall for the robot WelCH in simulation and filed experiment demonstrate the effectiveness of the proposed strategy.

Feasibility, planning and control of ground-wall transition for a suctorial hexapod robot

The control of a robot is optimized to improve its energy efficiency and stability in a geometrically complex environment For this purpose, analysis is performed on the dynamic modeling of a multi-body robot that can transition its position on corners where horizontal ground and a vertical wall intersect The robot consists of three bodies that can be attached to the wall by permanent magnetic adhesion and connected by links with two types of compliant joints: a passive type with a torsion spring and an active type with a torque-controlled motor A dynamics model is derived using the Lagrangian formulation, and investigated in the case of internal corner Difficulties in the analysis of dynamics for this wall-climbing robot came from how to manage external forces The external forces acting on the wall-climbing robot result from the wall and the magnets, which change the acting points of the forces Experiments were conducted to determine the magnetic force with respect to distance Simulation was then performed to verify the dynamic model The obtained dynamic model can offer a competent tool for the design and control of the autonomous wall-climbing robot, which can be used for the inspection of heavy-industry buildings, and oil tanks where the geometrically horizontal surface and the vertical wall intersect

Dynamic analysis during internal transition of a compliant multi-body climbing robot with magnetic adhesion

An analysis method to make the rocker bogie mechanism can climb up a stair is achieved in this paper. To verify whether the rocker bogie, with certain lengths of the linkages and radii of the wheels, could climb up a target stair or not, a kinematic analysis and its posture are determined. The trace of the center of mass of the rocker bogie was considered and the situation that three wheels contact the front side of the stair is analyzed. With this two analyses, the stair climbability graph (SCG) determined with the length and the height of a stair was drawn. The SCG shows the climbable stair group for the rocker bogie with certain size. Two prototypes of rocker bogie which has different lengths of linkages were designed and tested on two different stairs. As same result of the SCG, the first prototype rocker bogie with small rocker linkage can climb up the stair (length 450 mm and height 150 mm) but cannot climb up the other stair (length 300 mm and height 175 mm). The second prototype rocker bogie with large rocker linkage can climb up both stairs.

Analysis method of climbing stairs with the rocker-bogie mechanism

Payload capacity and transition ability are essential for climbing robots to apply the robots to various applications such as inspection and exploration. This paper presents a new climbing robotic platform with multi-link structure of track-wheel modules to enhance payload capacity and transition ability, and its tracking controller design and experimental results. The compliances between track-wheel modules achieve stable internal and external transitions while the large adhesion area of the track-wheel module enhances the payload capacity of the robot. Kinematic model-based tracking controller is designed and implemented for autonomous internal transition, and the gains of the controller are optimized by experimental design. Experiments on the automatic internal transitions are performed and the results guarantee autonomous internal transition with little tracking error. Keywords: climbing robot, multi-link robot, transition, tracking control, payload I. 서론 최근 국내외적으로 고층 외벽 청소, 선박 내부 검사 및 외부 도장과 같이 위험한 작업환경에서의 작업의 안전과 효율의 향상을 위해 등반로봇에 대한 연구가 활발하게 이루어지고 있다[1]. 등반로봇의 다양한 적용을 위하여 게코 섬모, 흡착 패드, 정전기력 등 다양한 부착 힘에 대한 연구와 등반로봇에 대한 메커니즘 연구 등이 활발히 수행 중이다[2-4]. 등반로봇이 실제 환경에서 장애물을 극복하고 다양한 작업을 하기 위해서는 벽면전환 능력과 유효하중 능력이 필수이다. 이러한 벽면전환 능력과 유효하중 능력과 관련하여 다양한 등반로봇 메커니즘들이 제안되었다. Fischer et al. [5]은 영구자석 바퀴를 이용한 등반로봇을 제안하였다. 이 로봇은 다양한 벽면전환을 할 수 있는 장점이 있지만, 유효하중 능력에 한계가 있다. Grieco et al. [6]은 6개의 흡착 다리를 지닌 등반로봇을 제안하였다. 6개의 다리를 이용하여 큰 유효하중을 들 수 있으나, 장애물 극복능력에는 한계가 있다. 최근, Seo and Sitti [7]는 유연한 조인트와 건식 접착을 이용한 다관절 등반로봇을 제안하였다. 제안된 로봇은 다양한 재질에 부착을 하고 높은 벽면전환 능력이 있다는 점에 장점이 있지만, 유효하중 능력에 한계가 있다. 본 논문에서는 다양한 벽면 전환 능력과 높은 유효하중 능력을 동시에 만족시키는 로봇 플랫폼을 제시한다. 로봇의 이름은 Combot이며 영구자석을 통해 벽면과 흡착을 한다. 다관절 구조로 구성되어 있으며, 유연한 조인트를 이용한 적응형 움직임을 통하여 다양한 벽면전환 능력 및 높은 유효하중 능력이 가능하다. 기존 논문 [8]에서 그 메커니즘 및 수동 조작을 통한 실험 결과가 공개된 바가 있으며, 본 논문의 전반부에서 메커니즘의 특징이 새롭게 요약, 제시된다. 본 논문에서는 기존 연구의 한계점인 수동 조작을 극복하기 위하여 벽면전환의 추종 제어기를 설계, 제시한다. 본 추종 제어를 통하여 로봇은 외부 조작 없이 자율적으로 벽면전환을 수행하게 된다. 기구학 모델을 바탕으로 비례적분 제어기를 통하여 추종 제어기가 설계되며, 제어기의 이득은 실험 방법론을 통하여 최적화된다. 최적화된 추종 제어기의 성능은 2종류의 벽면전환 실험을 통하여 그 성능이 검증된다. 본 논문의 구성은 다음과 같이 이루어 진다. II 장에서는 로봇의 메커니즘 및 성능에 대한 설명이 제시된다. III 장에서는 추종 제어를 위한 기구학 모델 및 비례적분 제어기에 대한 설명이 제시된다. IV 장에서는 비례적분 제어기의 이득 최적화에 대한 내용이 제시된다. V 장에서는 결론이 제시된다. II. 로봇 메커니즘 및 성능 1. 로봇 메커니즘 Combot은 그림 1과 같이 3개의 자석 트랙 모듈과 이를 연결하는 링크, 그리고 능동적으로 구동하는 1개의 꼬리로 이루어져 있다. 3개의 자석 트랙 모듈은 각각 능동 및 수동 회전 관절로 연결되어 있다. 로봇은 자석 트랙의 회전을 통하여 이동을 하며, 능동 및 수동 회전관절을 이용하여 벽면전환을 한다. 능동형 꼬리는 수직 벽 등반 시에 피치 백 모멘

https://www.koreascience.or.kr:443/article/JAKO201307651680079.pdf

Jongkyun Oh

Papers

Dynamic analysis during internal transition of a compliant multi-body climbing robot with magnetic adhesion

Analysis method of climbing stairs with the rocker-bogie mechanism

Development and Tracking Control of a Multi-Link Climbing Robot with High Payload Capacity and Various Transition Abilities