scholarly journals The Design and Building of a Hexapod Robot with Biomimetic Legs

2019 ◽  
Vol 9 (14) ◽  
pp. 2792
Author(s):  
Hwang ◽  
Liu ◽  
Yang ◽  
Lin
Keyword(s):  
Central Pattern Generator ◽  
Distributed Control ◽  
Pattern Generator ◽  
Mathematical Function ◽  
Distributed Control System ◽  
Hexapod Robot ◽  
Computational System ◽  
Computational Burden ◽  
Tripod Gait ◽  
The Brain

A hexapod robot with biomimetic legs was built to implement a distributed control system, where a mechanism is proposed to serve as the central pattern generator and a computer to act as the brain-stem, cooperating with the central pattern generator through wireless communication. The proposed mechanism is composed of two modules, i.e., the tripod gait generator and the Theo Jansen Linkage. The tripod gait generator is a device that uses a single motor to generate a tripod gait, while the Theo Jansen Linkage rhythmically executes the legged motion. In a sense, we are trying to implement the locomotion of a robot by means of a hybrid computational system, including the mechanism part and the electronic processors part. The complex mathematical function of the foot movement is realized by the ensemble of links of the Theo Jansen Linkage, so as to alleviate the computational burden. Besides, the proposed design, based on non-collocated actuators, is intended to minimize the number of actuators while reducing the building cost of the robot.

scholarly journals The central pattern generator underlying swimming in Dendronotus iris: a simple half-center network oscillator with a twist

2016 ◽  
Vol 116 (4) ◽  
pp. 1728-1742 ◽  
Author(s):  
Akira Sakurai ◽  
Paul S. Katz
Keyword(s):  
Central Pattern Generator ◽  
Body Wall ◽  
Impulse Activity ◽  
Motor Pattern ◽  
Pattern Generator ◽  
Excitatory Synapse ◽  
Dynamic Clamp ◽  
Motor Patterns ◽  
The Brain ◽  
Excitatory Drive

The nudibranch mollusc, Dendronotus iris, swims by rhythmically flexing its body from left to right. We identified a bilaterally represented interneuron, Si3, that provides strong excitatory drive to the previously identified Si2, forming a half-center oscillator, which functions as the central pattern generator (CPG) underlying swimming. As with Si2, Si3 inhibited its contralateral counterpart and exhibited rhythmic bursts in left-right alternation during the swim motor pattern. Si3 burst almost synchronously with the contralateral Si2 and was coactive with the efferent impulse activity in the contralateral body wall nerve. Perturbation of bursting in either Si3 or Si2 by current injection halted or phase-shifted the swim motor pattern, suggesting that they are both critical CPG members. Neither Si2 nor Si3 exhibited endogenous bursting properties when activated alone; activation of all four neurons was necessary to initiate and maintain the swim motor pattern. Si3 made a strong excitatory synapse onto the contralateral Si2 to which it is also electrically coupled. When Si3 was firing tonically but not exhibiting bursting, artificial enhancement of the Si3-to-Si2 synapse using dynamic clamp caused all four neurons to burst. In contrast, negation of the Si3-to-Si2 synapse by dynamic clamp blocked ongoing swim motor patterns. Together, these results suggest that the Dendronotus swim CPG is organized as a “twisted” half-center oscillator in which each “half” is composed of two excitatory-coupled neurons from both sides of the brain, each of which inhibits its contralateral counterpart. Consisting of only four neurons, this is perhaps the simplest known network oscillator for locomotion.

scholarly journals Gait Control of Hexapod Robot Based on Field-Programmable Gate Array and Central Pattern Generator

2020 ◽  
Vol 53 (6) ◽  
pp. 931-937
Author(s):  
Tianbo Qiao
Keyword(s):  
Central Pattern Generator ◽  
Field Programmable Gate Array ◽  
Control Method ◽  
Pattern Generator ◽  
Hexapod Robot ◽  
Gait Control ◽  
Field Programmable ◽  
Physical Prototype ◽  
Hardware Description ◽  
Gate Array

This paper attempts to improve the terrain adaptability of hexapod robot through gait control. Firstly, the multi-leg coupling in the tripodal gait of the hexapod robot was modeled by Hopf oscillator. Then, annular central pattern generator (CPG) was adopted to simulate the leg movements of hexapod robot between signals. Furthermore, a physical prototype was designed for the gait control test on field-programmable gate array (FPGA), and the algorithm of the rhythmic output of the model was programmed in Verilog, a hardware description language. Finally, the effectiveness of our gait control method was verified through the simulation on Xilinx. The results show that the phase difference of the CPG network remained stable; the designed hexapod robot moved at about 5.15cm/s stably in a tripodal gait, and outperformed wheeled and tracked robots in terrain adaptation. The research findings lay a solid basis for the design of all-terrain multi-leg robots.

Characterization by stimulation of medullary mechanisms underlying gasping neurogenesis

1985 ◽  
Vol 58 (1) ◽  
pp. 121-128 ◽  
Author(s):  
W. M. St John ◽  
T. A. Bledsoe ◽  
S. M. Tenney
Keyword(s):  
Brain Stem ◽  
Central Pattern Generator ◽  
Nucleus Tractus Solitarius ◽  
Pattern Generator ◽  
Nucleus Ambiguus ◽  
Refractory Periods ◽  
Pattern Generators ◽  
The Brain ◽  
Stimulation Of

Our purpose was to evaluate the hypothesis that neurons in the lateral tegmental field of the medulla comprise a pattern generator for neurogenesis of gasping. Stimulations in this area produced changes characteristic of pattern generators in other systems. These included shifts in gasping rhythm and refractory periods for eliciting gasps; the latter varied inversely with spontaneous gasping frequency. These responses were recorded from activities of phrenic and hypoglossal nerves of decerebrate, cerebellectomized, vagotomized, paralyzed, and ventilated cats. Gasping followed freezing the brain stem between pons and medulla. In addition to lateral tegmental loci, gasps were elicited by stimulating areas extending lateral to the nucleus ambiguus and medial to the contralateral medulla. These areas are envisaged to contain axons to or from the pattern generator of lateral tegmental field. Finally, stimulations in sites approximating nucleus tractus solitarius and nucleus ambiguus delayed spontaneous gasps and terminated ongoing gasps. Current required to terminate gasps fell during neural inspiration. Our data are consistent with the lateral tegmental field of medulla comprising a central pattern generator for gasping and pacemaker elements being a component of this pattern generator.

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