Climbing and Walking Robots

With the advancement of technology, new exciting approaches enable us to render mobile robotic systems more versatile, robust and cost-efficient. Some researchers combine climbing and walking techniques with a modular approach, a reconfigurable approach, or a swarm approach to realize novel prototypes as flexible mobile robotic platforms featuring all necessary locomotion capabilities. The purpose of this book is to provide an overview of the latest wide-range achievements in climbing and walking robotic technology to researchers, scientists, and engineers throughout the world. Different aspects including control simulation, locomotion realization, methodology, and system integration are presented from the scientific and from the technical point of view. This book consists of two main parts, one dealing with walking robots, the second with climbing robots. The content is also grouped by theoretical research and applicative realization. Every chapter offers a considerable amount of interesting and useful information

Design, Analysis and Fabrication of a Reconfigurable Stair Climbing Robot

Over the past few years, the scientists have tried to develop robots that can move on rough terrains. However, there are few robots that are suitable for use in rough terrains. A number of new technologies have evolved for reliable localization, obstacle avoidance and even autonomous map building in dynamically changing environment. However, mobility in very rough terrain is often very limited due to the absence of adequate locomotion concepts. The aim of this project is to introduce a new class of locomotive concept that will have excellent off-road capabilities. As a first prototype of this class, this four-wheeled robot will have the capability of climbing the stairs of height equal to its diameter. It will possess maximum gripping capacity and stability during motion in rough terrain owing to the 4 differential driven wheel configurations. The long -term goal of our research is to develop a robust outdoor platform which is suitable to be included in disaster mitigation as well as in security and surveillance missions. The platform should be able to transport application sensors to areas that are dangerous for humans to access, e.g. a collapse-endangered building or an industrial compound after a chemical accident. In those cases, before they enter, the rescue personnel might need some information about the air contamination or the whereabouts of people inside an area. The robot should be upgradeable with a variety of application sensors, e.g. cameras, thermal vision, or chemical sensors. To be usable in any search and rescue or security application, the robot has to be operational without changing batteries for at least two hours. As the first step into these future goals, our work has wireless control of the robot, which will steer the robot in the target area from remote. The robot will be wirelessly controlled through PC using ZigBee technology. In the future work, sensors, cameras, manipulators can be added to the robot frame. The robot can then serve complex tasks in dangerous areas remotely

Development of a Quadruped Robot and Parameterized Stair-Climbing Behavior

Stair-climbing is a difficult task for mobile robots to accomplish, particularly for legged robots. While quadruped robots have previously demonstrated the ability to climb stairs, none have so far been capable of climbing stairs of variable height while carrying all required sensors, controllers, and power sources on-board. The goal of this thesis was the development of a self-contained quadruped robot capable of detecting, classifying, and climbing stairs of any height within a specified range. The design process for this robot is described, including the development of the joint, leg, and body configuration, the design and selection of components, and both dynamic and finite element analyses performed to verify the design. A parameterized stair-climbing gait is then developed, which is adaptable to any stair height of known width and height. This behavior is then implemented on the previously discussed quadruped robot, which then demonstrates the capability to climb three different stair variations with no configuration change

Moving out of the lab:movement analyses in patients with osteoarthritis of the knee

Osteoarthritis of the knee is one of the main causes of physical limitations. In addition to osteoarthritis, obesity is also a growing public health problem. Research has shown that obese people are almost four times as likely to develop osteoarthritis of the knee. Patients with osteoarthritis of the knee develop compensation mechanisms during daily activities. This dissertation focuses on the analysis of biomechanical components in patients with osteoarthritis of the knee. The focus was on the knee adduction moment (KAM) during walking, stair climbing and sit-to-stand. A high KAM is associated with the onset and progression of osteoarthritis of the knee. Furthermore, this study focused on physical activity in patients with osteoarthritis of the knee with and without obesity. In this way, this research wanted to gain more insight into small changes in movement behaviour in these patients. Accelerometery is a good way to understand quantity and quality of physical activity. Patients with both osteoarthritis of the knee and obesity have a significantly increased KAM compared to healthy subjects. However, presence of only osteoarthritis of the knee, does not result in an increased KAM. Furthermore, more insight was gained into the actual physical activity and limitations in daily life in patients with osteoarthritis of the knee

Autonomous Behaviors With A Legged Robot

Over the last ten years, technological advancements in sensory, motor, and computational capabilities have made it a real possibility for a legged robotic platform to traverse a diverse set of terrains and execute a variety of tasks on its own, with little to no outside intervention. However, there are still several technical challenges to be addressed in order to reach complete autonomy, where such a platform operates as an independent entity that communicates and cooperates with other intelligent systems, including humans. A central limitation for reaching this ultimate goal is modeling the world in which the robot is operating, the tasks it needs to execute, the sensors it is equipped with, and its level of mobility, all in a unified setting. This thesis presents a simple approach resulting in control strategies that are backed by a suite of formal correctness guarantees. We showcase the virtues of this approach via implementation of two behaviors on a legged mobile platform, autonomous natural terrain ascent and indoor multi-flight stairwell ascent, where we report on an extensive set of experiments demonstrating their empirical success. Lastly, we explore how to deal with violations to these models, specifically the robot\u27s environment, where we present two possible extensions with potential performance improvements under such conditions

Characterisation of a nuclear cave environment utilising an autonomous swarm of heterogeneous robots

As nuclear facilities come to the end of their operational lifetime, safe decommissioning becomes a more prevalent issue. In many such facilities there exist ‘nuclear caves’. These caves constitute areas that may have been entered infrequently, or even not at all, since the construction of the facility. Due to this, the topography and nature of the contents of these nuclear caves may be unknown in a number of critical aspects, such as the location of dangerous substances or significant physical blockages to movement around the cave. In order to aid safe decommissioning, autonomous robotic systems capable of characterising nuclear cave environments are desired. The research put forward in this thesis seeks to answer the question: is it possible to utilise a heterogeneous swarm of autonomous robots for the remote characterisation of a nuclear cave environment? This is achieved through examination of the three key components comprising a heterogeneous swarm: sensing, locomotion and control. It will be shown that a heterogeneous swarm is not only capable of performing this task, it is preferable to a homogeneous swarm. This is due to the increased sensory and locomotive capabilities, coupled with more efficient explorational prowess when compared to a homogeneous swarm

Development of Walk Assistive Orthoses for Elderly

The proportion of elderly people is rapidly growing and the resources to help them will soon be insufficient. An important difficulty faced by the seniors is locomotion. Among the conditions that may be responsible for gait impairment, the reduced muscular force is one of the most frequent in elderly. This thesis focuses on the design and the evaluation of new solutions for assisting people with reduced vigor. Robotic orthoses are then used to support critical movements required for walking. Over the last two decades, the use of actuated orthotic devices for helping people suffering from gait disorders has been made possible. Recently, autonomous devices have even enabled spinal cord injured patients to walk again by mobilizing their paralyzed limbs. Addressing a completely different population, similar devices have been developed to augment healthy users' capabilities, for instance when heavy loads need to be carried. In this case, the wearer is in charge of the movements and the device simply follows the imposed trajectories. Extra load can then be carried by the exoskeleton without being felt by the user. The walk assistive devices developed as part of this thesis being intended for the elderly, they are at the intersection between these two classes of robotic orthosis. Indeed, most of the seniors who have difficulties to walk are able to move and therefore the mobilization devices are not adapted to them. Even though they need assistance, they surely do not want to have their movements imposed by a robotic device. The performance augmentation exoskeletons cannot help them either, as they simply follow the movements and only reject the external perturbations. A device that follows their movements and that adds the right amount of force when needed is therefore required. In order to achieve the demanding characteristics associated with assistive devices, new actuation solutions based on conventional electric motors are proposed. The combination of specifications in terms of overall weight, required assistance torque, dynamics capabilities or transparency when no support is provided is undeniably challenging. Various mechanisms are therefore presented to address these requirements. Two prototypes based on the proposed solutions are presented. The first one is based on a ball-screw transmission combined with linkages which provides a transmission ratio that is adapted to multiple walk related activities. The second one uses a transmission with clutches and an inversion mechanism which notably limits the losses due to the inertia of the actuation and greatly improves the natural transparency. In order to limit the obstructiveness of the assistive device, we propose to use partial devices that support specific movements. Two studies about the influence of such partial devices on gait are therefore presented. The first one focuses on identifying the potential sources of gait disturbance that orthotic device can induce. The second examines the effects of an assistive controller implemented on one of the developed prototypes. These studies demonstrate that even though the passive influence of a hip assistive orthosis on kinematic patterns is limited, the metabolic cost is increased. A moderate assistance cannot compensate for this undesirable effect but a link between the hip assistance and the ankle trajectory could be established. This is of major importance as the elderly tend to compensate for their weak ankle muscles with their hips

Design of Autonomous Cleaning Robot

Today, the research is concentrated on designing and developing robots to address the challenges of human life in their everyday activities. The cleaning robots are the class of service robots whose demands are increasing exponentially. Nevertheless, the application of cleaning robots is confined to smaller areas such as homes. Not much autonomous cleaning products are commercialized for big areas such as schools, hospitals, malls, etc. In this thesis, the proof of concept is designed for the autonomous floor-cleaning robot and autonomous board-cleaning robot for schools. A thorough background study is conducted on domestic service robots to understand the technologies involved in these robots. The components of the vacuum cleaner are assembled on a commercial robotic platform. The principles of vacuum cleaning technology and airflow equations are employed for the component selection of the vacuum cleaner. As the autonomous board-cleaning robot acts against gravity, a magnetic adhesion is used to adhere the robot to the classroom board. This system uses a belt drive mechanism to manoeurve. The use of belt drive increases the area of magnetic attraction while the robot is in motion. A semi-systematic approach using patterned path planning techniques for the complete coverage of the working environment is discussed in this thesis. The outcome of this thesis depicts a new and conceptual mechanical design of an autonomous floor-cleaning robot and an autonomous board-cleaning robot. This evidence creates a preliminary design for proof-of-concept for these robots. This proof of concept design is developed from the basic equations of vacuum cleaning technology, airflow and magnetic adhesion. A general overview is discussed for collaborating the two robots. This research provides an extensive initial step to illustrate the development of an autonomous cleaning robot and further validates with quantitative data discussed in the thesis

Negotiating uneven terrain by a simple teleoperated tracked vehicle with internally movable center of gravity

We propose a mechanical design for a simple teleoperated unmanned ground vehicle (UGV) to negotiate uneven terrain. UGVs are typically classified into legged, legged-wheeled, wheeled, and tanked forms. Legged vehicles can significantly shift their center of gravity (COG) by positioning their multi-articulated legs at appropriate trajectories, stepping over a high obstacle. To realize a COG movable mechanism with a small number of joints, a number of UGVs have been developed that can shift their COG by moving a mass at a high position above the body. However, these tend to pose a risk of overturning, and the mass must be moved quite far to climb a high step. To address these issues, we design a novel COG shift mechanism, in which the COG can be shifted forward and backward inside the body by moving most of its internal devices. Since this movable mass includes DC motors for driving both tracks, we can extend the range of the COG movement. We demonstrate that a conventional tracked vehicle prototype can traverse a step and a gap between two steps, as well as climb stairs and a steep slope, with a human operating the vehicle movement and the movable mass position