Design and dynamic simulation of a bionic crab robot based on line gear transmission
ZHANG Fanlin
ZHANG Linbeizi
DENG Yongquan
DING Jiang
Abstract：[Objective]Aiming at the tracking and motion limitations of traditional mobile robots,such as poor walking stability,intensive energy dissipation,and structural redundancy within unstructured terrains,a lightweight,highly adaptive hexapod bionic crab robot was developed by combining the mechanical advantages of space line gear transmission and kinematic biomimetic layout.[Methods]Firstly,symmetrical crank-rocker link configurations were synthesized to match the characteristic semi-elliptical foot trajectories of crabs.Secondly,a space line gear deceleration mechanism with a transmission ratio of 2 was constructed based on space curve meshing criteria,and its analytical equations for spatial contact and center lines were derived.Then,planar kinematic closed loops were formulated via the loop-closure vector technique to establish a high-ef-ficiency triangular gait with a duty cycle of 0.5,allowing quantitative tracking of the minimum stability margin.Thirdly,local dynamic constraints for individual linkages were mapped via D'Alembert's principle.Furthermore,case-level topology optimiza-tion setting a 70%mass retention threshold was executed via finite element analysis to eliminate low-stress materials from the aluminum side plates.Finally,a virtual prototype was exported into Adams software to conduct dynamic sweeps across challeng-ing terrains,including 15° upward/downward slopes and multi-level undulating obstacles.[Results]Parameter comparisons indicate that the developed line gear achieves a 2.1%weight reduction compared to conventional spur gears of the same specifications.After topology optimization,the equivalent von Mises stress and peak elastic strain of the side plates drop significantly,trimming the structural weight down to 74.52%of its baseline.Dynamic simulations across rough terrains demonstrate stable centroid displacements,harmonic velocity profiles,and continuous acceleration curves devoid of localized sudden impacts,confirming that the bionic coupling architecture guarantees superior motion stability and aggressive terrain clearance boundaries.
Keywords：Hexapod robotBionic designLine gearGait planningSimulation analysis
Publication Date：2026-07-15
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：11( 23-33 )