RHex: A Simple and Highly Mobile Hexapod Robot

Abstract

In this paper, the authors describe the design and control of RHex, a power autonomous, untethered, compliant-legged hexapod robot. RHex has only six actuators-one motor located at each hip-achieving mechanical simplicity that promotes reliable and robust operation in real-world tasks. Empirically stable and highly maneuverable locomotion arises from a very simple clock-driven, openloop tripod gait. The legs rotate full circle, thereby preventing the common problem of toe stubbing in the protraction (swing) phase. An extensive suite of experimental results documents the robot's significant "intrinsic mobility"-the traversal of rugged, broken, and obstacle-ridden ground without any terrain sensing or actively controlled adaptation. RHex achieves fast and robust forward locomotion traveling at speeds up to one body length per second and traversing height variations well exceeding its body clearance.

Spring-mass running: simple approximate solution and application to gait stability

“…In a recent investigation , a necessary condition for asymptotic stability could be derived when incorporating specific leg recirculation schemes relevant for the robot RHex (Saranli et al, 2001). Based on the factorization of return maps, in this special application, the condition was formulated as an exact algebraic expression without having to resort to the actual stancephase dynamics.…”

IONS: A Quadruped Robot for Multi-terrain Applications

“…The leg motions are periodic but have clever built-in compliant mechanism that helps in adapting to the irregularity of the terrain [8]. Loper [4], R-Hex [5] and Whegs [2] robots are the examples for this category. These robots can achieve impressive results on the terrain for which they are designed.…”

“…The curved leaves have been used in other robots like R-Hex [9], [8]. They are preferred over straight spokes as it allows a greater component of the ground reaction force in the vertical direction [5]. The robot attains static stability, if the number of leaves per wheg are greater than two.…”

“…We have followed whegged design approach for the locomotion of IONS robot. It can be categorized among those robots that can negotiate stairs with riser height greater than their hip height [2], [5]. The 3D Solidworks model and the implemented prototype of the IONS robot are shown in the Fig.…”

Design of Six Legged Spider Robot and Evolving Walking Algorithms

“…RHEX robot is the best known in multi legged robots [1]. RHEX is high performance six legged robot that does not include more complicated mechanism in structure (see Fig.…”