Reconstruction of Backbone Curves for Snake Robots

Wang, Tianyu; Lin, Benyao; Chong, Baxi; Whitman, Julian; Travers, Matthew; Goldman, Daniel I.; Blekherman, Grigoriy; Choset, Howie

doi:10.1109/lra.2021.3062331

Cited by 15 publications

(9 citation statements)

References 22 publications

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“…For snakes, their bodies form a series of sinusoidal curves in locomotion [41]. When the snake moves, the snake will rely on the friction between the abdominal scale and the ground to generate a driving force, so that the snake can move freely in the sand, grass and other places [42][43][44].…”

Section: Locomotion Analysis 31 the Locomotion Principlementioning

confidence: 99%

Design and locomotion analysis of modular soft robot

Liu

Wang

et al. 2022

Robotica

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In the paper, a novel modular soft robot that can crawl and turn is presented. The modular soft robot is composed of multiple drive modules connected in series, including one head module, one tail module and three body modules. Each module is actuated by the air chamber. Due to the nonlinear performance of the air chamber, the strain energy function of the air chamber is established. The relationship between the displacement of the air chamber expansion wall and the inflation pressure is obtained, and the manufacturing parameters of the air chamber are determined. By dividing the body of the robot into a series of continuous flexible models, the driving force and the friction force of the robot in locomotion are analyzed. An inflation and deflation control method is presented to complete the locomotion. According to the experiment, the crawling speed of the robot can reach 15.53 mm/s (0.03 body length per second). The turning speed of the robot can reach 1.273 °/s. The robot can crawl and turn on the rough blanket surface effectively. The robot can explore and move in a complex and changeable environment.

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Section: Locomotion Analysis 31 the Locomotion Principlementioning

confidence: 99%

Design and locomotion analysis of modular soft robot

Liu

Wang

et al. 2022

Robotica

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“…However, our snake robot, along with many others (Fu and Li, 2020;Rollinson et al, 2014;Takemori et al, 2018), only has pitch and yaw degrees of freedom (as shown in Figure 1(a)). If the robot's yaw and pitch joints directly employ the horizontal and vertical joint angle equations (as (3)-( 4)), the composed 3D configuration of the robot fails to capture the twist features in the desired 3D configuration (Wang et al, 2021). The inaccuracy of the 3D configuration can, in turn, cause an inaccurate contact pattern realization (CPR).…”

Section: Contact Pattern Realizationmentioning

confidence: 99%

“…Although in many cases such correspondence is reasonable, in some cases the discrepancy in the correspondence can lead to unexpected locomotion behavior. Therefore, we apply a 3D configuration optimization tool (Wang et al, 2021) to implement an accurate mapping from the desired contact pattern to the robot joint angles. In this section, we provide detailed steps to realize an arbitrary contact pattern.…”

Section: Contact Pattern Realizationmentioning

confidence: 99%

“…In this article, we develop an approach to stabilize statically unstable sidewinding gaits. We employ a 3D configuration optimization scheme (Wang et al, 2021) which calculates the robot's joint angles to realize a desired contact pattern. We show that the generated contact patterns can be accurately implemented on robots, which allows us to redesign the contact pattern and therefore stabilize the gaits.…”

Section: Introductionmentioning

confidence: 99%

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Frequency modulation of body waves to improve performance of sidewinding robots

Chong

Wang

Rieser

et al. 2021

The International Journal of Robotics Research

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Sidewinding is a form of locomotion executed by certain snakes and has been reconstructed in limbless robots; the gait is beneficial because it is effective in diverse terrestrial environments. Sidewinding gaits are generated by coordination of horizontal and vertical traveling waves of body undulation: the horizontal wave largely sets the direction of sidewinding with respect to the body frame while the vertical traveling wave largely determines the contact pattern between the body and the environment. When the locomotor’s center of mass leaves the supporting polygon formed by the contact pattern, undesirable locomotor behaviors (such as unwanted turning or unstable oscillation of the body) can occur. In this article, we develop an approach to generate desired translation and turning by modulating the vertical wave. These modulations alter the distribution of body–environment contact patches and can stabilize configurations that were previously statically unstable. The approach first identifies the spatial frequency of the vertical wave that statically stabilizes the locomotor for a given horizontal wave. Then, using geometric mechanics tools, we design the coordination between body waves that produces the desired translation or rotation. We demonstrate the effectiveness of our technique in numerical simulations and on experiments with a 16-joint limbless robot locomoting on flat hard ground. Our scheme broadens the range of movements and behaviors accessible to sidewinding locomotors at low speeds, which can lead to limbless systems capable of traversing diverse terrain stably and/or rapidly.

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“…Without using gait functions, scripted gaits are often implemented based on backbone. In this method, the snake robot configuration is approximated as a continuous backbone curve [ 8 , 9 ]. Yamada mathematically modeled the target curve based on the Frenet-Serret reference frame, decomposed the curvature into the corresponding axis directions of the yaw and pitch joints on the backbone, and deduced the rotation angles of each joint of the snake robot [ 10 ].…”

Section: Introductionmentioning

confidence: 99%

Gait Generation Method of Snake Robot Based on Main Characteristic Curve Fitting

et al. 2023

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Gait generation method is one of the important contents of snake robot motion control. Different gait generation methods produce completely different forms of control functions, so snake robots need more complicated programming logic and processes to realize various gaits and their transformation. Therefore, we propose a new unified expression of gait method, The MCC (main characteristics control) method simplifies and unifies the control functions of different snake robots gaits by extracting the main features of the backbone curves of snake robots gaits. Since all periodic curves that meet the Dirichlet conditions can be formed by superposition of sinusoidal curves, taking the “lowest frequency” part that reflects the main characteristics of the curve as the target configuration can simplify the motion control function of snake robots’ gaits. Based on the MCC method, some snake robot gaits are reconstructed, including serpentine gait, rolling gait, helix rolling gait, and crawler gait. In addition, based on MCC method, an AEH-sidewinding gait control method is proposed. The backbone of the AEH-sidewinding gait is closer to the ideal elliptic helix, thus improving the accuracy of its kinematics modeling of snake robot sidewinding gait. Finally, the validity of this gait is verified by experiments. This unified gait expression of snake robots will be helpful to realize smooth gait switching between different gaits of snake robots.

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Reconstruction of Backbone Curves for Snake Robots

Cited by 15 publications

References 22 publications

Design and locomotion analysis of modular soft robot

Design and locomotion analysis of modular soft robot

Frequency modulation of body waves to improve performance of sidewinding robots

Gait Generation Method of Snake Robot Based on Main Characteristic Curve Fitting

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