Five-Wheeled Wheelchair with an Add-On Mechanism and Its Semiautomatic Step-Climbing and -Descending Function

In this chapter, we propose a novel add-on electric drive system for propelling a manual wheelchair on the floor together with an advanced function to climb and descend a step with no human support. The proposed add-on mechanism consists of an active-caster drive wheel and a reconfigurable link mechanism with a linear actuator to change the location of the drive wheel relative to a wheelchair. By attaching the mechanism to a manual wheelchair, we build a five-wheeled wheelchair. Since the drive wheel is attached on the back of the wheelchair, a risk of falling to the back is significantly reduced. To surmount a step with no help, we develop a step-climbing and -descending strategy by using the proposed wheelchair with a reconfigurable link mechanism. The five-wheel configuration guarantees a static stability of the wheelchair when some wheels are hovered from the ground. The function is used in step-climbing and -descending strategies to realize the transfer of a wheelchair user. In order to reduce the effort of a wheelchair user to control the complicated step surmount strategies, semiautomatic system is installed on the prototype wheelchair whose availability is verified through experiments

Review article: locomotion systems for ground mobile robots in unstructured environments

Abstract. The world market of mobile robotics is expected to increase substantially in the next 20 yr, surpassing the market of industrial robotics in terms of units and sales. Important fields of application are homeland security, surveillance, demining, reconnaissance in dangerous situations, and agriculture. The design of the locomotion systems of mobile robots for unstructured environments is generally complex, particularly when they are required to move on uneven or soft terrains, or to climb obstacles. This paper sets out to analyse the state-of-the-art of locomotion mechanisms for ground mobile robots, focussing on solutions for unstructured environments, in order to help designers to select the optimal solution for specific operating requirements. The three main categories of locomotion systems (wheeled - W, tracked - T and legged - L) and the four hybrid categories that can be derived by combining these main locomotion systems are discussed with reference to maximum speed, obstacle-crossing capability, step/stair climbing capability, slope climbing capability, walking capability on soft terrains, walking capability on uneven terrains, energy efficiency, mechanical complexity, control complexity and technology readiness. The current and future trends of mobile robotics are also outlined

New Technologies for Climbing Robots Adhesion to Surfaces

The interest in the development of climbing robots is growing steadily. The main motivations are to increase the operation e ciency, by eliminating the costly assembly of sca olding, or to protect human health and safety in hazardous tasks. Climbing robots have already been developed for applications ranging from cleaning to inspection of constructions di cult to reach. These robots should be capable of travelling over di erent types of surfaces, with di erent inclinations, such as oors, walls, ceilings, and to walk between such surfaces. Furthermore, they should be able of adapting and recon guring for di erent environment conditions and to be self-contained. Regarding the adhesion to the surface, the robots should be able to produce a secure gripping force using a light-weight mechanism. This paper presents a survey of di erent technologies proposed and adopted for climbing robots adhesion to surfaces, focusing on the new technologies that are recently being developed to ful ll these objectives.N/

변신 바퀴를 이용한 다중 지형 이동 로봇의 설계

학위논문 (석사)-- 서울대학교 대학원 : 기계항공공학부, 2014. 2. 주종남.In this paper, the design, optimization, and performance evaluation of a new wheel-leg hybrid robot are reported. This robot utilizes a novel kind of transformable wheel for its locomotion to combine the advantages of both circular wheels and legged wheels. To minimize design complexity, this new transformable wheels transformation process is operated passively, which eliminates the need for additional actuators. A new triggering mechanism is also employed to increase the success rate of the transformation. To maximize the climbing ability in the legged-wheel mode, the design parameters of the transformable wheel and the robot are tuned based on behavioral analyses. The performance of our new development is evaluated in terms of stability, energy efficiency, and the maximum height of the obstacle the robot can climb over. By virtue of this transformable wheel, the system could climb over an obstacle 3.25 times as tall as its wheel radius, not compromising its driving ability at 2.4 body lengths per second with the specific resistance of 0.7 on flat surfaces.Abstract Contents List of Figures & Tables 1. Introduction 2. Design of the passive transformable wheel 2.1 Components design for coupled legs 2.2 Transformation mechanism 2.3 Triggering mechanism 2.4 Climbing scenario 3. Design optimization 3.1 Modeling of the passive transformable wheel 3.2 Maximizing the transformation ratio 3.3 Foot design for the higher success rate of the transformation 4. Design of the robotic platform 4.1 Features 4.2 Tuning design parameters for stable climbing 5. Results 5.1 Speed & specific resistance 5.2 Obstacle climbing 5.3 Discussion about mode switch 6. Conclusions References 국문초록Maste

The Design, Manufacture, and Testing of a Novel Adhesion System for a Climbing Vehicle

We present the design and fabrication of a prototype wall-climbing vehicle employing a unique combined locomotion and adhesion system in which the adhesive vacuum is transmitted through moving, perforated treads. Implementing the adhesion/drive system involved a broad range of design challenges, including: developing reliable sealing of sliding and static interfaces, understanding the frictional interactions between the drive treads and various vehicle components and surfaces on which they ride, as well as designing for lightness, manufacturability, and adjustability. The clean sheet design presented in this thesis was taken from concept to functioning prototype in less than 6 months, requiring a considered mix of off-the-shelf components, custom fabrication, and outsourced production. Proof of concept testing is reviewed, including static pressure and force results as well as dynamic vertical surface maneuverability trials

Robust self-propulsion in sand using simply controlled vibrating cubes

Much of the Earth and many surfaces of extraterrestrial bodies are composed of in-cohesive particle matter. Locomoting on granular terrain is challenging for common robotic devices, either wheeled or legged. In this work, we discover a robust alternative locomotion mechanism on granular media -- generating movement via self-vibration. To demonstrate the effectiveness of this locomotion mechanism, we develop a cube-shaped robot with an embedded vibratory motor and conduct systematic experiments on diverse granular terrains of various particle properties. We investigate how locomotion changes as a function of vibration frequency/intensity on granular terrains. Compared to hard surfaces, we find such a vibratory locomotion mechanism enables the robot to move faster, and more stable on granular surfaces, facilitated by the interaction between the body and surrounding granules. The simplicity in structural design and controls of this robotic system indicates that vibratory locomotion can be a valuable alternative way to produce robust locomotion on granular terrains. We further demonstrate that such cube-shape robots can be used as modular units for morphologically structured vibratory robots with capabilities of maneuverable forward and turning motions, showing potential practical scenarios for robotic systems

An Overview of Legged Robots

The objective of this paper is to present the evolution and the state-of-theart in the area of legged locomotion systems. In a first phase different possibilities for mobile robots are discussed, namely the case of artificial legged locomotion systems, while emphasizing their advantages and limitations. In a second phase an historical overview of the evolution of these systems is presented, bearing in mind several particular cases often considered as milestones on the technological and scientific progress. After this historical timeline, some of the present day systems are examined and their performance is analyzed. In a third phase are pointed out the major areas for research and development that are presently being followed in the construction of legged robots. Finally, some of the problems still unsolved, that remain defying robotics research, are also addressed.N/