Weaver: Hexapod robot for autonomous navigation on unstructured terrain

Abstract

Legged robots are an efficient alternative for navigation in challenging terrain. In this paper we describe Weaver, a six‐legged robot that is designed to perform autonomous navigation in unstructured terrain. It uses stereo vision and proprioceptive sensing based terrain perception for adaptive control while using visual‐inertial odometry for autonomous waypoint‐based navigation. Terrain perception generates a minimal representation of the traversed environment in terms of roughness and step height. This reduces the complexity of the terrain model significantly, enabling the robot to feed back information about the environment into its controller. Furthermore, we combine exteroceptive and proprioceptive sensing to enhance the terrain perception capabilities, especially in situations in which the stereo camera is not able to generate an accurate representation of the environment. The adaptation approach described also exploits the unique properties of legged robots by adapting the virtual stiffness, stride frequency, and stride height. Weaver's unique leg design with five joints per leg improves locomotion on high gradient slopes, and this novel configuration is further analyzed. Using these approaches, we present an experimental evaluation of this fully self‐contained hexapod performing autonomous navigation on a multiterrain testbed and in outdoor terrain.

Walking Posture Adaptation for Legged Robot Navigation in Confined Spaces

“…In addition to simulations we implemented the full pipeline from Fig. 4 on the hexapod robot Weaver [1]. Weaver is a sixlegged robot with 5 degrees of freedom for each leg and is capable of climbing 30 • inclines.…”

“…Their many degrees of freedom (DOF) enable navigation of challenging environments including confined spaces. Hexapod robots such as Weaver [1] and Lauron V [2] are very stable statically and capable of walking on rough terrain and up steep inclines. MAX [3], an Ultralight Legged Robot (ULR) was designed to maximise locomotion efficiency in challenging outdoor environments.…”

Whole-Body Motion Planning for a Six-Legged Robot Walking on Rugged Terrain

“…The black balls in the figure correspond to rotational joints of the robot. In this simulation, the robot is commanded to walk across the rugged terrain patch along a given walking path using the alternating-tripod gait [7,[22][23][24].…”

Obstacle Avoidance and Terrain Identification for a Hexapod Robot

“…Gerardo Bledt et al [7,8] introduced the MIT Cheetah 3, a quadrupedal robot which is demonstrated by a low cost of transport (COT). Marko Bjelonic et al [9] introduced a six-legged robot which performs autonomous navigation in unstructured terrain. Feng Gao et al [10][11][12] introduced a six-parallel-legged robot which can walk on irregular terrain while keeping the body balance and complete tasks like opening the door with haptic information.…”