Passive compliant quadruped robot using Central Pattern Generators for locomotion control

Abstract

We present a new quadruped robot, "Cheetah", featuring three-segment pantographic legs with passive compliant knee joints. Each leg has two degrees of freedom-knee and hip joint can be actuated using proximal mounted RC servo motors, force transmission to the knee is achieved by means of a bowden cable mechanism. Simple electronics to command the actuators from a desktop computer have been designed in order to test the robot. A Central Pattern Generator (CPG) network has been implemented to generate different gaits. A parameter space search was performed and tested on the robot to optimize forward velocity.

Horse-like walking, trotting, and galloping derived from kinematic Motion Primitives (kMPs) and their application to walk/trot transitions in a compliant quadruped robot

“…To try to exploit the potential of legged locomotion a number of solutions have been developed for robots of varying size, powered by diverse energy sources. Among these, notable examples include Fujita and Kitano (1998); Berns et al (1998); Canderle and Caldwell (2000); Nichol et al (2004); Poulakakis et al (2005); Buehler et al (2005); Zhang et al (2005); Kimura et al (2007); Raibert et al (2008); Hirose et al (2009);Semini et al (2011). Quadrupedal locomotion presents good intrinsic stability features, but the coordination of the motion of four legs is non-trivial to control.…”

“…Quadrupedal locomotion presents good intrinsic stability features, but the coordination of the motion of four legs is non-trivial to control. Different trajectory generation techniques have been adopted (Kimura et al, 1989;Raibert, 1990;Sakakibara et al, 1990;Kramy and Orin, 2003;Golubovic and Hu, 2003a,b;Tsujita et al, 2005;Hu and Gu, 2005;Iida et al, 2005;Kim et al, 2006;Rebula et al, 2007;Pongas et al, 2007;Hebbel et al, 2007;Chae and Park, 2008;Kim et al, 2008), and the efforts in this field of research led to proficient results in the development of different gaits, from the slow walk to gallop. Raibert (1986) provides a good overview of legged locomotion, with particular attention given to quadrupeds.…”

“…For this reason many researchers have sought to analyze animal gait (Hoyt and Taylor, 1981), with the aim of reproducing this on robots. Different methods for biological inspirations have been proposed: Collins and Richmond (1994); Fukuoka et al (1999Fukuoka et al ( , 2003; Billard and Ijspeert (2000); Fujii et al (2002); Witte et al (2003); Ishii et al (2004); Son et al (2006); Cappelletto et al (2006Cappelletto et al ( , 2007; Righetti and Ijspeert (2008) ;Rutishauser et al (2008); Liu et al (2009), with the well known theory of Central Pattern Generators (CPG) forming a common theme. According to the theory of CPG, open-loop signals are produced in the spinal cord and sent to the limbs to produce the motion, reducing significantly the complexity of controlling a vast variety of motions.…”

New Variable Passive-Compliant Element Design for Quadruped Adaptation to Stiffness-Varying Terrain

“…Today's robots use fixed-value springs to provide compliance during leg contact [13,14]. The energy accumulated in the compliant elements is partially recovered, while the lost energy from the spring damping is restored by leg actuation on the next stride.…”

Living with robots : investigating the user acceptance of social robots in domestic environments

“…The choice and design of physical features is thus guided purely by the role the robot has to fulfill. Examples of functional robots are Roomba (Forlizzi & DiSalvo, 2006;Jones, Lawson, & Mills, 2008;Sung et al, 2009), Packbot (Yamaughi, 2004), Cheetah (Rutishauser et al, 2008), PeopleBot (Dautenhahn et al, 2006;Woods et al, 2005), Lucas the library robot (Behan & O'Keeffee, 2008), and Roball (Salter, Werry, & Michaud, 2008). Although a robot's shape has an impact on the interactions with human users, all shapes have their own potentials.…”