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1 – 3 of 3T.A. Guardabrazo and P. Gonzalez de Santos
An energetic model for walking robots based on both dynamic and actuator models is proposed in this paper. While applied to walking machines, this method allows the evaluation of…
Abstract
An energetic model for walking robots based on both dynamic and actuator models is proposed in this paper. While applied to walking machines, this method allows the evaluation of the influence of leg configuration, body weight, and gait parameters on power consumption. The model is validated by using genetic algorithms to identify the unknown parameters, which enables it to be used as a tool to evaluate and optimize the performance of a legged robot configuration according to the power consumption. This method has been applied to find the optimum stride length for the minimum energy expenditure of a biped prototype depending on the speed and payload, considering both level and slope walking.
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Zijie Niu, Aiwen Zhan and Yongjie Cui
The purpose of this study is to test a chassis robot on rugged road cargo handling.
Abstract
Purpose
The purpose of this study is to test a chassis robot on rugged road cargo handling.
Design/methodology/approach
Attitude solution of D-H series robot gyroscope speed and acceleration sensor.
Findings
In identical experimental environments, hexapodal robots experience smaller deviations when using a four-footed propulsive gait from a typical three-footed gait for forward motion; for the same distance but at different speeds, the deviation basically keeps itself within the same range when the robot advances forward with four-foot propulsive gait; because the foot slide in the three-footed gait sometimes experiences frictions, the robot exhibits a large gap in directional deviations in different courses during motion; for motion using a four-footed propulsive gait, there are minor directional deviations of hexapodal robots resulting from experimental errors, which can be reduced through optimizing mechanical structures.
Originality/value
Planning different gaits can solve problems existing in some typical gaits. This article has put forward a gait planning method for hexapodal robots moving forward with diverse gaits as a redundant multifreedom structure. Subsequent research can combine a multiparallel-legged structure to analyze kinematics, optimize the robot’s mechanical structure and carry out in-depth research of hexapod robot gaits.
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Antonio Gonzalez Rodriguez, Angel Gonzalez Rodriguez and Pierluigi Rea
The paper aims to present a new mechanical scheme for a leg to be included in legged vehicles that simplifies the control actuations along the stride.
Abstract
Purpose
The paper aims to present a new mechanical scheme for a leg to be included in legged vehicles that simplifies the control actuations along the stride.
Design/methodology/approach
The scheme includes three four‐bar links grouped in two mechanisms. The first one decouples the vertical and horizontal foot movements. The second one produces a constant horizontal foot velocity when the corresponding motor is given a constant speed. A hybrid robot with wheels at the end of the hind legs has been simulated and constructed to validate the leg performance.
Findings
The gait control requires only five commands for the electronic cards to control the leg. Decoupling vertical and horizontal movements allows a more adequate selection of actuators, a reduction of energy consumption, and higher load capacity and robot velocity. Additional mechanical benefits, such as improved robustness and lower inertia, are obtained. The hind legs can also be articulated, allowing the robot to overcome an obstacle and to climb up and down stairs.
Research limitations/implications
A hybrid robot offers greater stability with respect to a legged robot. This way the lateral movement is not a concern, and therefore it has not been tested yet during the walking cycle.
Originality/value
This new scheme obtains a quasi‐Cartesian behaviour for the foot movement that drastically simplifies the control of the walking cycle. Although the decoupling between movements has already been obtained in previous configurations, these follow a pantograph structure and suffer from blocking problems when they are subject to lateral forces. These schemes were suitable for crab‐like gaits. The proposed leg moves according to a mammal‐like gait.
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