Selection Algorithm for Locomotion Based on the Evaluation of Falling Risk

Abstract

An environmentally specific type of locomotion (e.g., bipedal or quadrupedal walking) is effective only under the specified environments. However, other conditions could cause physical body constraints and decrease mobility. Despite these constraints, legged robots are desired with high overall mobility such that they can walk under various conditions. Thus, a combination of types of locomotion is needed to maximize overall mobility. We have developed a gorilla-type robot, which can switch between bipedal and quadrupedal walking. A selection technique to optimize locomotion choice would be beneficial to the robot, which will experience challenging situations when walking through complex terrains, receiving disturbances, or malfunctioning. We present a selection algorithm for locomotion (SAL) that improves overall mobility by autonomously selecting the optimal locomotion. The falling risk of each locomotion mode is evaluated with a Bayesian network to represent the robot's situation. The evaluation function for the SAL determines the optimal locomotion choice based on falling risk and moving speed. In this paper, the SAL is used for two state variables of locomotion: gait (Ga-SAL) and speed (Sp-SAL). Both the simulations and experiments validated that the robot traveled efficiently in complex environments.Index Terms-Biomimetics, falling risk, learning and adaptive systems, legged robots, selection algorithm for locomotion (SAL).

Unified bipedal gait for walking and running by dynamics-based virtual holonomic constraint in PDAC

“…(10), (15), and (25), by exposing the relation between them and the performance, and to apply our selection method [12], [13]. This idea enhances both energy efficiency and adaptability of the unified bipedal gait by autonomous optimization for the faced situation.…”

Adaptive Control Strategies for Interlimb Coordination in Legged Robots: A Review

“…The transition from quadrupedal gait to upright and bipedal gait is a challenging task for legged robots, because it requires drastic changes in locomotor movements (Asa et al, 2009 ; Aoi et al, 2012 ; Kobayashi et al, 2015 ). In particular, because the robot has to raise its trunk so that the arms leave the ground, an adequate relationship between the supporting limb locations and the center of mass location is important.…”

Influence of trunk structure on posture transition from quadrupedalism to bipedalism

“…Therefore, it is important to achieve quick transition from quadrupedalism to bipedalism. There are some approaches toward achieving posture transition between quadrupedal and bipedal locomotion [7][8][9][10][11]. In [7,8], authors proposed controllers for the transition utilizing Central Pattern Generator.…”

“…In [7,8], authors proposed controllers for the transition utilizing Central Pattern Generator. In [9,10], strategies were proposed for the transition. To our knowledge, few studies have discusses faster transition.…”