A Double-Layered Artificial Delay-Based Approach for Maneuvering Control of Planar Snake Robots

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Joyjit Mukherjee ◽  
Spandan Roy ◽  
Indra Narayan Kar ◽  
Sudipto Mukherjee
Keyword(s):  
Structural Complexity ◽  
Snake Robot ◽  
Control Approach ◽  
Constraint Manifold ◽  
Ground Conditions ◽  
Output System ◽  
Gait Function ◽  
Virtual Holonomic Constraints ◽  
Velocity Tracking ◽  
Snake Robots

Uncertainty and disturbance are common in a planar snake robot model due to its structural complexity and variation in system parameters. To achieve efficient head angle and velocity tracking with least computational complexity and unknown uncertainty bounds, a time-delayed control (TDC) scheme has been presented in this paper. A Serpenoid gait function is being tracked by the joint angles utilizing virtual holonomic constraints (VHCs) method. The first layer of TDC has been proposed for stabilizing the VHC dynamics to the origin. Once the VHCs are satisfied, the system is said to be on the constraint manifold. The second layer of TDC has been applied to an output system defined over the reduced order dynamics on the constrained manifold. To establish the robustness of the control approach through simulation, uncertainty in the friction coefficients is considered to be time-varying emulating change in the ground conditions. Simulation results and Lyapunov stability analysis affirm the uniformly ultimately bounded stability of the robot employing the proposed approach.

Bio-Inspired Snake Robots

2018 ◽  
pp. 246-275 ◽  
Author(s):  
Mohammadali Javaheri Koopaee ◽  
Cid Gilani ◽  
Callum Scott ◽  
XiaoQi Chen
Keyword(s):  
Future Research ◽  
Snake Robot ◽  
Cluttered Environments ◽  
Flat Surfaces ◽  
Robot Locomotion ◽  
Control Schemes ◽  
Unstructured Environment ◽  
And Control ◽  
World Environment ◽  
Snake Robots

This chapter concerns modelling and control of snake robots. Specifically, the authors' main goal is introducing some of the fundamental design, modelling, and control approaches introduced for efficient snake robot locomotion in cluttered environments. This is a critical topic because, unlike locomotion in flat surfaces, where pre-specified gait equations can be employed, for locomotion in unstructured environment more sophisticated control approaches should be used to achieve intelligent and efficient mobility. To reach this goal, shape-based modelling approaches and a number of available control schemes for operation in unknown environments are presented, which hopefully motivates more scholars to start working on snake robots. Some ideas about future research plans are also proposed, which can be helpful for fabricating a snake robot equipped with the necessary features for operation in a real-world environment.

Modeling and Mechanical Analysis of Snake Robots on Cylinders

2019 ◽  
Vol 11 (4) ◽  
Author(s):  
Chaoquan Tang ◽  
Peng Li ◽  
Gongbo Zhou ◽  
Deyuan Meng ◽  
Xin Shu ◽  
...  
Keyword(s):  
Mechanical Analysis ◽  
Point Of View ◽  
The Body ◽  
Optimal Method ◽  
Tree Structures ◽  
Snake Robot ◽  
Mechanical Models ◽  
And Performance ◽  
The Relationship ◽  
Snake Robots

The narrow and redundant body of the snake robot makes it suitable for the inspection of complex bar structures, such as truss or tree structures. One of the key issues affecting the efficient motion of snake robots in complex bar structures is the development of mechanical models of snake robots on cylinders. In other words, the relationship between the payload and structural and performance parameters of the snake robot is still difficult to clarify. In this paper, the problem is approached with the Newton–Euler equations and the convex optimal method. Firstly, from the kinematic point of view, the optimal attitude of the snake robot wrapped around the cylinder is found. Next, the snake robot is modeled on the cylinder and transformed into a convex optimization problem. Then, the relationship between the payload of the snake robot on the cylinder and the geometric and attitude parameters of the body of snake robots is analyzed. Finally, the discussion for the optimal winding attitude and some advices for the design of the snake robot are proposed. This study is helpful toward the optimal design of snake robots, including geometry parameters and motor determination.

scholarly journals A Head Control Strategy of the Snake Robot Based on Segmented Kinematics

2019 ◽  
Vol 9 (23) ◽  
pp. 5104
Author(s):  
Yunhu Zhou ◽  
Yuanfei Zhang ◽  
Fenglei Ni ◽  
Hong Liu
Keyword(s):  
Control Strategy ◽  
Control Strategies ◽  
The Body ◽  
Head Part ◽  
Joint Angles ◽  
Backbone Curve ◽  
Snake Robot ◽  
Head Control ◽  
Neck Part ◽  
Snake Robots

Head control is important for snake robots to work in an unknown environment. However, the existing methods of head control have certain application limitations for snake robots with different configurations. Thus, a strategy for head control based on segmented kinematics is proposed. Compared with the existing head control strategies, our strategy can adapt to different structures of snake robots, whether wheeled or non-wheeled. In addition, our strategy can realize the accurate manipulation of the snake robot head. The robot body is divided into the base part, neck part and head part. First, parameters of backbone curve are optimized for enlarging the area of the support polygon. Then the desired pose for the head link and the dexterous workspace of the head part can in turn derive the desired position and direction of the end frame for the neck part. An optimization algorithm is proposed to help the end frame of the neck part approach a desired one and obtains the joint angles of the neck part. When the actual frames of the neck part are determined, the dexterous workspace of the head part will cover the desired pose of the head link. Then the TRAC-IK inverse kinematics algorithm is adopted to solve the joint angles of the head part. To avoid the collision between the body and the ground, a trajectory planning method of the overall body in Cartesian space is proposed. Finally, simulations validate the effectiveness of the control strategy.

scholarly journals Snake Robot with Driving Assistant Mechanism

2020 ◽  
Vol 10 (21) ◽  
pp. 7478
Author(s):  
Junseong Bae ◽  
Myeongjin Kim ◽  
Bongsub Song ◽  
Maolin Jin ◽  
Dongwon Yun
Keyword(s):  
Dynamic Simulation ◽  
Degree Of Freedom ◽  
Rough Terrain ◽  
Snake Robot ◽  
Wide Range ◽  
Locomotion Speed ◽  
High Degree ◽  
Snake Robots

Snake robots are composed of multiple links and joints and have a high degree of freedom. They can perform various motions and can overcome various terrains. Snake robots need additional driving algorithms and sensors that acquire terrain data in order to overcome rough terrains such as grasslands and slopes. In this study, we propose a driving assistant mechanism (DAM), which assists locomotion without additional driving algorithms and sensors. In this paper, we confirmed that the DAM prevents a roll down on a slope and increases the locomotion speed through dynamic simulation and experiments. It was possible to overcome grasslands and a 27 degrees slope without using additional driving controllers. In conclusion, we expect that a snake robot can conduct a wide range of missions well, such as exploring disaster sites and rough terrain, by using the proposed mechanism.

scholarly journals Lateral Oscillation and Body Compliance Help Snakes and Snake Robots Stably Traverse Large, Smooth Obstacles

2020 ◽  
Vol 60 (1) ◽  
pp. 171-179
Author(s):  
Qiyuan Fu ◽  
Sean W Gart ◽  
Thomas W Mitchel ◽  
Jin Seob Kim ◽  
Gregory S Chirikjian ◽  
...  
Keyword(s):  
Surface Friction ◽  
Static Stability ◽  
Three Dimensions ◽  
Step Height ◽  
Snake Robot ◽  
Flat Surfaces ◽  
Lateral Oscillation ◽  
Continuous Body ◽  
Base Of Support ◽  
Snake Robots

Abstract Snakes can move through almost any terrain. Similarly, snake robots hold the promise as a versatile platform to traverse complex environments such as earthquake rubble. Unlike snake locomotion on flat surfaces which is inherently stable, when snakes traverse complex terrain by deforming their body out of plane, it becomes challenging to maintain stability. Here, we review our recent progress in understanding how snakes and snake robots traverse large, smooth obstacles such as boulders and felled trees that lack “anchor points” for gripping or bracing. First, we discovered that the generalist variable kingsnake combines lateral oscillation and cantilevering. Regardless of step height and surface friction, the overall gait is preserved. Next, to quantify static stability of the snake, we developed a method to interpolate continuous body in three dimensions (3D) (both position and orientation) between discrete tracked markers. By analyzing the base of support using the interpolated continuous body 3-D kinematics, we discovered that the snake maintained perfect stability during traversal, even on the most challenging low friction, high step. Finally, we applied this gait to a snake robot and systematically tested its performance traversing large steps with variable heights to further understand stability principles. The robot rapidly and stably traversed steps nearly as high as a third of its body length. As step height increased, the robot rolled more frequently to the extent of flipping over, reducing traversal probability. The absence of such failure in the snake with a compliant body inspired us to add body compliance to the robot. With better surface contact, the compliant body robot suffered less roll instability and traversed high steps at higher probability, without sacrificing traversal speed. Our robot traversed large step-like obstacles more rapidly than most previous snake robots, approaching that of the animal. The combination of lateral oscillation and body compliance to form a large, reliable base of support may be useful for snakes and snake robots to traverse diverse 3-D environments with large, smooth obstacles.

Navigation and Obstacle Avoidance of Snake-Robot Guided by a Co-Robot UAV Visual Servoing

2020 ◽  
Author(s):  
Mahdi Haghshenas-Jaryani ◽  
Hakki Erhan Sevil ◽  
Liang Sun
Keyword(s):  
Obstacle Avoidance ◽  
Autonomous Navigation ◽  
Visual Servoing ◽  
Integrated System ◽  
Ground Vehicles ◽  
Snake Robot ◽  
Cluttered Environments ◽  
Localization And Mapping ◽  
Path Planner ◽  
Snake Robots

Abstract This paper presents the concept of teaming up snake-robots, as unmanned ground vehicles (UGVs), and unmanned aerial vehicles (UAVs) for autonomous navigation and obstacle avoidance. Snake robots navigate in cluttered environments based on visual servoing of a co-robot UAV. It is assumed that snake-robots do not have any means to map the surrounding environment, detect obstacles, or self-localize, and these tasks are allocated to the UAV, which uses visual sensors to track the UGVs. The obtained images were used for the geo-localization and mapping the environment. Computer vision methods were utilized for the detection of obstacles, finding obstacle clusters, and then, mapping based on Probabilistic Threat Exposure Map (PTEM) construction. A path planner module determines the heading direction and velocity of the snake robot. A combined heading-velocity controller was used for the snake robot to follow the desired trajectories using the lateral undulatory gait. A series of simulations were carried out for analyzing the snake-robot’s maneuverability and proof-of-concept by navigating the snake robot in an environment with two obstacles based on the UAV visual servoing. The results showed the feasibility of the concept and effectiveness of the integrated system for navigation.

scholarly journals Maneuvering Control of Planar Snake Robots Using Virtual Holonomic Constraints

2016 ◽  
Vol 24 (3) ◽  
pp. 884-899 ◽  
Author(s):  
Alireza Mohammadi ◽  
Ehsan Rezapour ◽  
Manfredi Maggiore ◽  
Kristin Y. Pettersen
Keyword(s):  
Holonomic Constraints ◽  
Virtual Holonomic Constraints ◽  
Snake Robots

Gait Fitting Algorithms for Snake Robots With Binary Actuators

2012 ◽  
Author(s):  
Yunjie Miao ◽  
Feng Gao ◽  
Yong Zhang
Keyword(s):  
Snake Robot ◽  
Fitting Algorithm ◽  
Lateral Undulation ◽  
Best Fitting ◽  
Different Dimensions ◽  
Binary Actuators ◽  
Snake Robots

This paper introduces a new snake robot with binary actuators and mainly focuses on the simulations of various snake gaits. Three categories of fitting algorithms are proposed. They are 1) Fitting Algorithm of One Module; 2) Position-Fitting Algorithm of Multiple Modules; 3) Configuration-Fitting Algorithm of Multiple Modules. All the fitting algorithms and their fitting results are elaborated in simulations of lateral undulation, one of the most widely used snake gaits. As the best fitting algorithm for lateral undulation, Configuration-Fitting Algorithm of Four Modules is also applied to a snake robot of different dimensions to demonstrate that it is a universal gait fitting algorithm for all kinds of snake robots with binary actuators.

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