Perception-Driven Obstacle-Aided Locomotion for Snake Robots: The State of the Art, Challenges and Possibilities †

Abstract

In nature, snakes can gracefully traverse a wide range of different and complex environments. Snake robots that can mimic this behaviour could be fitted with sensors and transport tools to hazardous or confined areas that other robots and humans are unable to access. In order to carry out such tasks, snake robots must have a high degree of awareness of their surroundings (i.e., perception-driven locomotion) and be capable of efficient obstacle exploitation (i.e., obstacle-aided locomotion) to gain propulsion. These aspects are pivotal in order to realise the large variety of possible snake robot applications in real-life operations such as fire-fighting, industrial inspection, search-and-rescue, and more. In this paper, we survey and discuss the state of the art, challenges, and possibilities of perception-driven obstacle-aided locomotion for snake robots. To this end, different levels of autonomy are identified for snake robots and categorised into environmental complexity, mission complexity, and external system independence. From this perspective, we present a step-wise approach on how to increment snake robot abilities within guidance, navigation, and control in order to target the different levels of autonomy. Pertinent to snake robots, we focus on current strategies for snake robot locomotion in the presence of obstacles. Moreover, we put obstacle-aided locomotion into the context of perception and mapping. Finally, we present an overview of relevant key technologies and methods within environment perception, mapping, and representation that constitute important aspects of perception-driven obstacle-aided locomotion.

Field Navigation Using Fuzzy Elevation Maps Built with Local 3D Laser Scans

“…Autonomous navigation of unmanned ground vehicles (UGVs) requires detailed and updated information on the environment obtained from onboard sensors [1]. Laser rangefinders are sensors commonly employed to obtain three-dimensional (3D) point clouds of the area where the mobile robot moves.…”

Snake-Like Robot with Fusion Gait for High Environmental Adaptability: Design, Modeling, and Experiment

“…A sensory-perceptual system is required to help snake-like robots perceive environments and determine locomotion gait, thereby improving the adaptability of the robots. [16] Another issue that is worth studying is the performance of snake-like robots on different surface types. When such a robot moves on smooth ground, the serpentine locomotion may be invalid because of the insufficient radial friction.…”

“…They may push against rocks, branches, or other obstacles to move forward more efficiently." In obstacle-aided locomotion, the snake-like robot utilizes external objects, such as walls, stones, and other obstacles, for propulsion [16]. In narrow paths, both side walls serve as a fulcrum.…”

Head-Raising of Snake Robots Based on a Predefined Spiral Curve Method

“…Snake robots' common motion modes include serpentine [3,4], traveling wave [5,6], concertina [7,8], and sidewinding [9,10] locomotion. Additionally, some researchers sought to find other motion modes such as fusion gait [11] and obstacle-aided locomotion [12]. However, these motion modes provide limited visual information.…”