Bioinspired snake robotics has been a highly active area of research over the years and resulted in many prototypes. Much of these prototypes takes the form of serially jointed-rigid bodies. The emergence of soft robotics contributed to a new type of snake robots made from compliant and structurally deformable modules. Leveraging the controllable large bending, these robots can naturally generate various snake locomotion gaits. Here, we investigate the swimming locomotion of soft robotic snakes. A numerically efficient dynamic model of the robot is first derived. Then, a distributed contact modal is augmented to incorporate hydrodynamic forces. The model is then numerically tested to identify the optimal bending propagation for efficient swimming. Results show that the soft robotic snakes have high potential to be used in marine applications.
DePaul University（德保罗大学）；University of Arkansas（阿肯色大学）
Snakes are a remarkable evolutionary success story. Many snake-inspired robots have been proposed over the years. Soft robotic snakes (SRS) with their continuous and smooth bending capability better mimic their biological counterparts' unique characteristics. Prior SRSs are limited to planar operation with a limited number of planar gaits. We propose a novel SRS with spatial bending and investigate snake locomotion gaits beyond the capabilities of the state-of-the-art systems. We derive a complete floating-base kinematic model of the robot and use the model to derive jointspace trajectories fo…
DePaul University（德保罗大学）；Texas A&M University（得克萨斯农工大学）；Georgia Institute of Technology（佐治亚理工学院）；Louisiana S. University（路易斯安那州立大学）
Soft robotic snakes made of compliant materials can continuously deform their bodies and, therefore, mimic the biological snakes' flexible and agile locomotion gaits better than their rigid-bodied counterparts. Without wheel support, to date, soft robotic snakes are limited to emulating planar locomotion gaits, which are derived via kinematic modeling and tested on robotic prototypes. Given that the snake locomotion results from the reaction forces due to the distributed contact between their skin and the ground, it is essential to investigate the locomotion gaits through efficient dynamic mod…
DePaul University（德保罗大学）；Texas A&M University（德克萨斯农工大学）；Georgia Institute of Technology（佐治亚理工学院）
Soft robotic snakes (SRSs) have a unique combination of continuous and compliant properties that allow them to imitate the complex movements of biological snakes. Despite the previous attempts to develop SRSs, many have been limited to planar movements or use wheels to achieve locomotion, which restricts their ability to imitate the full range of biological snake movements. We propose a new design for the SRSs that is wheelless and powered by pneumatics, relying solely on spatial bending to achieve its movements. We derive a kinematic model of the proposed SRS and utilize it to achieve two sna…
In this paper, we present a new locomotion control method for soft robot snakes. Inspired by biological snakes, our control architecture is composed of two key modules: A deep reinforcement learning (RL) module for achieving adaptive goal-tracking behaviors with changing goals, and a central pattern generator (CPG) system with Matsuoka oscillators for generating stable and diverse locomotion patterns. The two modules are interconnected into a closed-loop system: The RL module, analogizing the locomotion region located in the midbrain of vertebrate animals, regulates the input to the CPG system…
Worcester Polytechnic Institute（伍斯特理工学院）；NVIDIA（英伟达）；University of Copenhagen（哥本哈根大学）
In this work we present a framework that is capable of accurately representing soft robotic actuators in a multiphysics environment in real-time. We propose a constraint-based dynamics model of a 1-dimensional pneumatic soft actuator that accounts for internal pressure forces, as well as the effect of actuator latency and damping under inflation and deflation and demonstrate its accuracy a full soft robotic snake with the composition of multiple 1D actuators. We verify our model's accuracy in static deformation and dynamic locomotion open-loop control experiments. To achieve real-time performa…
In this paper, we present a model-free learning-based control scheme for the soft snake robot to improve its contact-aware locomotion performance in a cluttered environment. The control scheme includes two cooperative controllers: A bio-inspired controller (C1) that controls both the steering and velocity of the soft snake robot, and an event-triggered regulator (R2) that controls the steering of the snake in anticipation of obstacle contacts and during contact. The inputs from the two controllers are composed as the input to a Matsuoka CPG network to generate smooth and rhythmic actuation inp…
Locomotion of an Elastic Snake Robot via Natural Dynamics
German Aerospace Center (DLR), Robotics and Mechatronics Center (RMC)（德国航空航天中心（DLR）机器人与机电中心）；Technical University of Munich (TUM), Department of Computer Engineering（慕尼黑技术大学（TUM）计算机工程系）
Snake robots, comprised of sequentially connected joint actuators, have recently gained increasing attention in the industrial field, like life detection in narrow space. Such robots can navigate through the complex environment via the cooperation of multiple motors located on the backbone. However, controlling the robots in an unknown environment is challenging, and conventional control strategies can be energy inefficient or even fail to navigate to the destination. In this work, a snake locomotion gait policy is developed via deep reinforcement learning (DRL) for energy-efficient control. W…
Collaborative Robotics and Intelligent Systems (CoRIS) Institute, Oregon State University（俄勒冈州立大学协作机器人与智能系统（CoRIS）研究所）；Bard College at Simon’s Rock（巴德学院西蒙洛克分校）；Olin College of Engineering（奥林工程学院）；Carnegie Mellon University（卡内基梅隆大学）
Snake robots are characterized by their ability to navigate through small spaces and loose terrain by utilizing efficient cyclic forms of locomotion. Soft snake robots are a subset of these robots which utilize soft, compliant actuators to produce movement. Prior work on soft snake robots has primarily focused on planar gaits, such as undulation. More efficient spatial gaits, such as sidewinding, are unexplored gaits for soft snake robots. We propose a novel means of constructing a soft snake robot capable of sidewinding, and introduce the Helical Inflating Soft Snake Robot (HISSbot). We valid…
We optimize three-dimensional snake kinematics for locomotor efficiency. We assume a general space-curve representation of the snake backbone with small-to-moderate lifting off the ground and negligible body inertia. The cost of locomotion includes work against friction and internal viscous dissipation. When restricted to planar kinematics, our population-based optimization method finds the same types of optima as a previous Newton-based method. A few types of optimal motions prevail. We find an s-shaped body with alternating lifting of the middle and ends for small-to-moderate transverse fric…
Faced with strong demand for robots working in underwater pipeline environments, a novel underwater multi-model locomotion robot is designed and studied in this research. By mimicking the earthworm's metameric body, the robot is segmented in the structure; by synthesizing the earthworm-like peristaltic locomotion mechanism and the propeller-driven swimming mechanism, the robot possesses unique multi-mode locomotion capability. In detail, the in-pipe earthworm-like peristaltic crawling is achieved based on servomotor-driven cords and pre-bent spring-steel belts that work antagonistically, and t…
Snakes can traverse almost all types of environments by bending their elongate bodies in 3-D to interact with the terrain. Similarly, a snake robot is a promising platform to perform critical tasks in various environments. Understanding how 3-D body bending effectively interacts with the terrain for propulsion and stability can not only inform how snakes traverse natural environments, but also allow snake robots to achieve similar performance. How snakes and snake robots move on flat surfaces has been understood well. However, such ideal terrain is rare in natural environments and little was u…
Carnegie Mellon University（卡内基梅隆大学）；Georgia Institute of Technology（佐治亚理工学院）
Snake robots composed of alternating single-axis pitch and yaw joints have many internal degrees of freedom, which make them capable of versatile three-dimensional locomotion. In motion planning process, snake robot motions are often designed kinematically by a chronological sequence of continuous backbone curves that capture desired macroscopic shapes of the robot. However, as the geometric arrangement of single-axis rotary joints creates constraints on the rotations in the robot, it is challenging for the robot to reconstruct an arbitrary 3D curve. When the robot configuration does not accur…
Learning, locomotion, and navigation of soft synthetic snakes in three-dimensional, heterogeneous environments
Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana–Champaign（卡尔·R·沃塞基因组生物学研究所，伊利诺伊大学厄巴纳-香槟分校）；Department of Mechanical and Aerospace Engineering, Hong Kong University of Science and Technology（香港科学与技术大学机械与航空航天工程系）；Department of Mechanical Science and Engineering, University of Illinois Urbana–Champaign（伊利诺伊大学厄巴纳-香槟分校机械科学与工程系）
University of California San Diego（加州大学圣地亚哥分校）；Technion – Israel Institute of Technology（以色列理工学院）
Exploring and navigating in extreme environments, such as caves, oceans, and planetary bodies, are often too hazardous for humans, and as such, robots are possible surrogates. These robots are met with significant locomotion challenges that require traversing a wide range of surface roughnesses and topologies. Previous locomotion strategies, involving wheels or ambulatory motion, such as snake platforms, have success on specific surfaces but fail in others which could be detrimental in exploration and navigation missions. In this paper, we present a novel approach that combines snake-like robo…
Indian Institute of Technology Roorkee（印度理工学院鲁尔基分校）；Kyungpook National University（庆北国立大学）
This paper presents the design and dynamic modelling of a soft pneumatic actuator that can be used to mimic snake or worm-like locomotion. The bond graph technique is used to derive the dynamics of the actuator. To validate the accuracy of the derived dynamic model, we conduct numerical simulations using 20-sim software. Experimental results demonstrate that the soft actuator achieves bi-directional bending and linear displacement, which is essential for mimicking snake or worm-like locomotion
Visvesvaraya National Institute of Technology（维斯瓦拉亚国家理工学院）；Carnegie Mellon University（卡内基梅隆大学）；Inbitorobotics（Inbitorobotics公司）；Robotics Institute, Carnegie Mellon University（卡内基梅隆大学机器人研究所）
Studying snake robot locomotion in a cluttered environment has been a complicated task because the motion model is discontinuous due to the physical contact with obstacles, and the contact force cannot be determined solely by contact positions. We present a unique mathematical model of the robot interacting with obstacles in which the contact forces are mapped on the basis of a viscous friction model. Also a motion planning strategy has been introduced which helps deriving the simplest path that ensures sufficient number of contacts of the robot with the obstacles required to reach a goal posi…
Rectilinear forms of snake-like robotic locomotion are anticipated to be an advantage in obstacle-strewn scenarios characterizing urban disaster zones, subterranean collapses, and other natural environments. The elongated, laterally-narrow footprint associated with these motion strategies is well-suited to traversal of confined spaces and narrow pathways. Navigation and path planning in the absence of global sensing, however, remains a pivotal challenge to be addressed prior to practical deployment of these robotic mechanisms. Several challenges related to visual processing and localization ne…
A Novel Aerial-Aquatic Locomotion Robot with Variable Stiffness Propulsion Module
UC Center for Robotics Research, College of Engineering and Applied Science, University of Cincinnati（辛辛那提大学工程与应用科学学院UC机器人研究中心）；Robotics Institute, School of Computer Science, Carnegie Mellon University（卡内基梅隆大学计算机学院机器人研究所）；Mohamed bin Zayed U（穆罕默德·本·扎耶德大学）
Deep reinforcement learning has recently been applied to a variety of robotics applications, but learning locomotion for robots with unconventional configurations is still limited. Prior work has shown that, despite the simple modeling of articulated swimmer robots, such systems struggle to find effective gaits using reinforcement learning due to the heterogeneity of the search space. In this work, we leverage insight from geometric models of these robots in order to focus on promising regions of the space and guide the learning process. We demonstrate that our augmented learning technique is …
Robots "in-the-wild" encounter and must traverse widely varying terrain, ranging from solid ground to granular materials like sand to full liquids. Numerous approaches exist, including wheeled and legged robots, each excelling in specific domains. Screw-based locomotion is a promising approach for multi-domain mobility, leveraged in exploratory robotic designs, including amphibious vehicles and snake robotics. However, unlike other forms of locomotion, there is a limited exploration of the models, parameter effects, and efficiency for multi-terrain Archimedes screw locomotion. In this work, we…
Technical University of Munich（慕尼黑工业大学）；Ludwig Maximilian University of Munich（路德维希-马克西米利安-慕尼黑大学）；Sun Yat-sen University（中山大学）
Similar to their counterparts in nature, the flexible bodies of snake-like robots enhance their movement capability and adaptability in diverse environments. However, this flexibility corresponds to a complex control task involving highly redundant degrees of freedom, where traditional model-based methods usually fail to propel the robots energy-efficiently. In this work, we present a novel approach for designing an energy-efficient slithering gait for a snake-like robot using a model-free reinforcement learning (RL) algorithm. Specifically, we present an RL-based controller for generating loc…
ARCSnake V2: Mechanical Adaptations For An Amphibious Multi-Domain Screw-Propelled Snake-Like Robot
Mechanical and Aerospace Engineering Department, University of California San Diego（加州大学圣地亚哥分校机械与航空航天工程系）；Electrical and Computer Engineering Department, University of California, San Diego（加州大学圣地亚哥分校电气与计算机工程系）
In this paper, we present an approach to study the behavior of compliant plates in granular media and optimize the performance of a robot that utilizes this technique for mobility. From previous work and fundamental tests on thin plate force generation inside granular media, we introduce an origami-inspired mechanism with non-linear compliance in the joints that can be used in granular propulsion. This concept utilizes one-sided joint limits to create an asymmetric gait cycle that avoids more complicated alternatives often found in other swimming/digging robots. To analyze its locomotion as we…
Non-planar snake gaits: from Stigmatic-starts to Sidewinding
Harvard University（哈佛大学）；Indian Institute of Technology Bombay（印度理工学院孟买分校）；National Center for Supercomputing Applications（国家超级计算应用中心）；Carl R. Woese Institute for Genomic Biology（卡尔·R·沃斯基因组生物学研究所）；University of Illinois at Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校）；A.T. Still University of Health Sciences（A.T. 斯蒂尔健康科学大学）；Kirksville College of Osteopathic Medicine（柯克斯维尔整骨医学院）
