Novel Vine-like Continuum Robot for Environmental Exploration Applications

This thesis details a new design and novel operational strategies for nature inspired, thin tendril continuum robots. Instead of taking inspiration for robot design from insects or animals, the novel approach to continuum robotics herein takes inspiration and adapts operational concepts from plant life. In particular, an innovative strategy is developed which mimics behaviors observed in vines and other climbing plants. Specifically, a tendril robot with prickles was developed and deployed to actively seek environmental contact, exploiting the mechanical advantage gained by bracing against the environment using the prickles. The resulting performance enhancements over previously developed smooth backbone tendril robot designs, and use of strategies that do not attempt to interact with the environment are empirically demonstrated with the new robot prototype. Results of further experiments suggest applications in which the new design and approach could prove useful to the scientific and wider communities

A Dexterous Tip-extending Robot with Variable-length Shape-locking

Soft, tip-extending "vine" robots offer a unique mode of inspection and manipulation in highly constrained environments. For practicality, it is desirable that the distal end of the robot can be manipulated freely, while the body remains stationary. However, in previous vine robots, either the shape of the body was fixed after growth with no ability to manipulate the distal end, or the whole body moved together with the tip. Here, we present a concept for shape-locking that enables a vine robot to move only its distal tip, while the body is locked in place. This is achieved using two inextensible, pressurized, tip-extending, chambers that "grow" along the sides of the robot body, preserving curvature in the section where they have been deployed. The length of the locked and free sections can be varied by controlling the extension and retraction of these chambers. We present models describing this shape-locking mechanism and workspace of the robot in both free and constrained environments. We experimentally validate these models, showing an increased dexterous workspace compared to previous vine robots. Our shape-locking concept allows improved performance for vine robots, advancing the field of soft robotics for inspection and manipulation in highly constrained environments.Comment: 7 pages,10 figures. Accepted to IEEE International Conference on Rootics and Automation (ICRA) 202

Analysis and Experiments for Tendril-Type Robots

New models for the Tendril continuous backbone robot, and other similarly constructed robots, are introduced and expanded upon in this thesis. The ability of the application of geometric models to result in more precise control of the Tendril manipulator is evaluated on a Tendril prototype. We examine key issues underlying the design and operation of \u27soft\u27 robots featuring continuous body (\u27continuum\u27) elements. Inspiration from nature is used to develop new methods of operation for continuum robots. These new methods of operation are tested in experiments to evaluate their effectiveness and potential

Trunk Robot for Extended Environments

We describe the design and physical realization of a novel type of large-scale continuum robot. The design, based on a hybrid concentric-tube/tendon actuated structure, is realized at a significantly larger scale than previous concentric tube continuum robots, with an extended length well over one meter. While operation at this scale opens up new types of potential applications, realization at this scale presents interesting challenges. We detail and discuss the associated issues via the prototyping and testing of the physical system with the help of experiments

Highly Manoeuvrable Eversion Robot Based on Fusion of Function with Structure

Despite their soft and compliant bodies, most of today’s soft robots have limitations when it comes to elongation or extension of their main structure. In contrast to this, a new type of soft robot called the eversion robot can grow longitudinally, exploiting the principle of eversion. Eversion robots can squeeze through narrow openings, giving the possibility to access places that are inaccessible by conventional robots. The main drawback of these types of robots is their limited bending capability due to the tendency to move along a straight line. In this paper, we propose a novel way to fuse bending actuation with the robot’s structure. We devise an eversion robot whose body forms both the central chamber that acts as the backbone as well as the actuators that cause bending and manoeuvre the manipulator. The proposed technique shows a significantly improved bending capability compared to externally attaching actuators to an eversion robot showing a 133% improvement in bending angle. Due to the increased manoeuvrability, the proposed solution is a step towards the employment of eversion robots in remote and difficult-to-access environments

Soft robotics for infrastructure protection

The paradigm change introduced by soft robotics is going to dramatically push forward the abilities of autonomous systems in the next future, enabling their applications in extremely challenging scenarios. The ability of soft robots to safely interact and adapt to the surroundings is key to operate in unstructured environments, where the autonomous agent has little or no knowledge about the world around it. A similar context occurs when critical infrastructures face threats or disruptions, for examples due to natural disasters or external attacks (physical or cyber). In this case, autonomous systems may be employed to respond to such emergencies and have to be able to deal with unforeseen physical conditions and uncertainties, where the mechanical interaction with the environment is not only inevitable but also desirable to successfully perform their tasks. In this perspective, I discuss applications of soft robots for the protection of infrastructures, including recent advances in pipelines inspection, rubble search and rescue, and soft aerial manipulation, and promising perspectives on operations in radioactive environments, underwater monitoring and space exploration

Nonlinear model predictive growth control of a class of plant-inspired soft growing robots

Recently, researchers have shown an increased interest in considering plants as a model of inspiration for designing new robot locomotions. Growing robots, that imitate the biological growth presented by plants, have proved irresistible in unpredictable and distal environments due to their morphological adaptation and tip-extension capabilities. However, as a result of the irreversible growing process exhibited by growing robots, classical control schemes could fail in obtaining feasible solutions that respect the permanent growth constraint. Thus, in this article, a Nonlinear Model Predictive Control (NMPC) scheme is proposed to guarantee the robot’s performance towards point stabilization while respecting the constraints imposed by the growing process and the control limits. The proposed NMPC-based growth control has applied to the kinematic model of the recently proposed plant-inspired robots in the literature, namely, vine-like growing robots. Numerical simulations have been performed to show the effectiveness of the proposed NMPC-based growth control in terms of point stabilization, disturbance rejection, and obstacle avoidance and encouraging results were obtained. Finally, the robustness of the proposed NMPC-based growth control is analyzed against various input disturbances using Monte-Carlo simulations that could guide the tuning process of the NMPC