Multi-contact bipedal robotic locomotion

Abstract

This paper presents a formal framework for achieving multi-contact bipedal robotic walking, and realizes this methodology experimentally on two robotic platforms: AMBER2 and Assume The Robot Is A Sphere (ATRIAS). Inspired by the key feature encoded in human walkingmulti-contact behavior-this approach begins with the analysis of human locomotion and uses it to motivate the construction of a hybrid system model representing a multi-contact robotic walking gait. Human-inspired outputs are extracted from reference locomotion data to characterize the human model or the spring-loaded invert pendulum (SLIP) model, and then employed to develop the human-inspired control and an optimization problem that yields stable multi-domain walking. Through a trajectory reconstruction strategy motivated by the process that generates the walking gait, the mathematical constructions are successfully translated to the two physical robots experimentally.

Dynamic Output Controllers for Exponential Stabilization of Periodic Orbits for Multidomain Hybrid Models of Robotic Locomotion

“…HZD-based controllers have been validated numerically and experimentally for (i) 2D and 3D bipedal robots, including RABBIT [17,18], MA-BEL [19][20][21], ERNIE [22], AMBER [23], ATRIAS [24][25][26][27], and DURUS [28,29] prototypes, (ii) powered prosthetic legs [30][31][32][33], (iii) exoskeletons [34], (iv) monopedal robots [35,36], and (v) quadruped robots [37]. In the HZD approach, a set of output functions, referred to as virtual constraints, is defined for the continuous-time dynamics of the system and asymptotically driven to zero by partial linearizing feedback controllers [38].…”

Exponentially Stabilizing Controllers for Multi-Contact 3D Bipedal Locomotion

“…where 20is a BMI condition, and from the LMI (21) and the Schur complement lemma, η is an upper bound on the 2-norm of ∆ξ, i.e., η > ∆ξ 2 2 . The cost function (19) then minimizes a weighted sum of −γ and µ with the weighting factor w > 0 as a tradeoff between improving the convergence rate and minimizing η to have a good approximation based on the Taylor series expansion.…”

“…However, transverse linearization and HZD-based controllers are the only controllers of these methods that explicitly deal with general cases of underactuation. HZD-based controllers have been validated numerically and experimentally for 2D and 3D bipedal robots [10]- [19], 2D and 3D powered prosthetic legs [20]- [25], exoskeletons [26], monopedal [27] and quadruped robots [28]. In this approach, a set of output functions, referred to as virtual constraints, is defined for the continuous-time dynamics of the system and asymptotically driven to zero by the input-output (I-O) linearizing feedback controller [29].…”

Hierarchical Decentralized Control of a 5-Link Biped Robot

“…x (t) 2 S; (4) where S is the set of all feasible states belonging to the walking surface de ned as follows:…”

“…Robots and, especially, biped robots have been a research magnate in the last decades [1][2][3][4][5][6][7][8], giving rise to fascinating robots and products. To achieve such great products, a wide range of topics from studying biological locomotion and their mechanical model, model formulation, methods of gait synthesis, and the mechanical realization of biped robots to the control of such systems have been addressed in the literature, e.g., see [9][10][11][12][13][14].…”