Study on Optimization of CPG Model for Lower Limb Prosthesis

2013 ◽  
Vol 461 ◽  
pp. 633-640
Author(s):  
Xin Guo ◽  
Ming Yue Li ◽  
Cai Yu Xu
Keyword(s):  
Control Method ◽  
Three Dimensional ◽  
Pattern Generator ◽  
Joint Angles ◽  
Camera System ◽  
Walking Gait ◽  
Lower Limb Prosthesis ◽  
Transfemoral Amputees ◽  
Hopf Oscillator ◽  
Limb Prosthesis

A Multitude of different prosthesis designs have been developed for restoring transtibial and transfemoral amputees’ mobility.But yet,most of them are considered as passive devices.Therefore,more and more researchers develop bionic controller that simulate the biological certral pattern generator,namely CPG.This paper presents a new control method using bipedal robotics technology and bio-inspiration based on CPG.To begin with,we present the fundamental measurement of human walking gait and the device mainly includes three-dimensional camera system,digitized movements analyzer and so on.We choose hopf oscillators as CPG simulation unit.And after several tests,five oscillators are just right for a single joint.We change the simple hopf oscillator equation.Thus corresponding to the knee,CPG modeling finally generate actual human angle curve.Then we define learning equation as learning a given periodic signal.By trying different values of the different parameters we obtain the desired walking curve of knee joint.Using the obtained parameters,learning equation reproduce knee joint angle.According to the signal of the accelerometer that placed in the hip to adjust learning equation,so the amputees can easily control the speed of walking.Matlab simulation results show that the same trend with changes in human joint angles,which lay a good foundation for the control of active prostheses.

Walking quality guaranteed central pattern generator control method

2013 ◽  
Vol 228 (3) ◽  
pp. 569-579
Author(s):  
Jiaqi Zhang ◽  
Xiaolei Han ◽  
Xueying Han
Keyword(s):  
Central Pattern Generator ◽  
Control Method ◽  
Central Pattern Generators ◽  
Pattern Generator ◽  
Walking Robots ◽  
High Quality ◽  
Traditional Methods ◽  
Walking Gait ◽  
Pattern Generators ◽  
Periodic Inputs

Creating effective locomotion for a legged robot is a challenging task. Central pattern generators have been widely used to control robot locomotion. However, one significant disadvantage of the central pattern generator method is its inability to design high-quality walks because it only produces sine or quasi-sine signals for motor control as compared to most cases in which the expected control signals are more advanced. Control accuracy is therefore diminished when traditional methods are replaced by central pattern generators resulting in unaesthetically pleasing walking robots. In this paper, we present a set of solutions, based on testings of Sony’s four-legged robotic dog (AIBO), which produces the same walking quality as traditional methods. First, we designed a method based on both evolution and learning to optimize the walking gait. Second, a central pattern generator model was put forth to enabled AIBO to learn from arbitrary periodic inputs, which resulted in the replication of the optimized gait to ensure high-quality walking. Lastly, an accelerator sensor feedback was introduced so that AIBO could detect uphill and downhill terrains and change its gait according to the surrounding environment. Simulations were performed to verify this method.

Study of the Control of Active Transfemoral Prosthesis Based on CPG

2012 ◽  
Vol 468-471 ◽  
pp. 1710-1713
Author(s):  
Yan Li Geng ◽  
Peng Yang ◽  
Ling Ling Chen
Keyword(s):  
Dynamical System ◽  
Power Generation ◽  
Central Pattern Generator ◽  
Lower Limb ◽  
3D Model ◽  
Pattern Generator ◽  
Passive Devices ◽  
Transfemoral Amputees ◽  
Hopf Oscillator ◽  
Transfemoral Prosthesis

Commercial transfemoral prostheses remain limited to energetically passive devices. Intelligent prostheses still do not replace the power generation capabilities of the missing limb. Active Transfemoral Prosthesis is designed to compensate the movements of transfemoral amputees. Base on the function and principle of huaman lower limb, Active transfemoral prosthesis is designed. Virtual prototype of active transfemoral prosthesis 3D model is built through Solidworks. A dynamical system is used to generate a position trajectory to control a linear motor replacing the missing joint. Hopf oscillator is used to construct a central pattern generator (CPG), which makes up the dynamical system.

scholarly journals Enhancing functional abilities and cognitive integration of the lower limb prosthesis

2019 ◽  
Vol 11 (512) ◽  
pp. eaav8939 ◽  
Author(s):  
Francesco Maria Petrini ◽  
Giacomo Valle ◽  
Marko Bumbasirevic ◽  
Federica Barberi ◽  
Dario Bortolotti ◽  
...  
Keyword(s):  
Lower Limb ◽  
Sensory Feedback ◽  
Cognitive Effort ◽  
Limb Amputation ◽  
Functional Abilities ◽  
Haptic Information ◽  
Lower Limb Prosthesis ◽  
Transfemoral Amputees ◽  
The Brain ◽  
Limb Prosthesis

Lower limb amputation (LLA) destroys the sensory communication between the brain and the external world during standing and walking. Current prostheses do not restore sensory feedback to amputees, who, relying on very limited haptic information from the stump-socket interaction, are forced to deal with serious issues: the risk of falls, decreased mobility, prosthesis being perceived as an external object (low embodiment), and increased cognitive burden. Poor mobility is one of the causes of eventual device abandonment. Restoring sensory feedback from the missing leg of above-knee (transfemoral) amputees and integrating the sensory feedback into the sensorimotor loop would markedly improve the life of patients. In this study, we developed a leg neuroprosthesis, which provided real-time tactile and emulated proprioceptive feedback to three transfemoral amputees through nerve stimulation. The feedback was exploited in active tasks, which proved that our approach promoted improved mobility, fall prevention, and agility. We also showed increased embodiment of the lower limb prosthesis (LLP), through phantom leg displacement perception and questionnaires, and ease of the cognitive effort during a dual-task paradigm, through electroencephalographic recordings. Our results demonstrate that induced sensory feedback can be integrated at supraspinal levels to restore functional abilities of the missing leg. This work paves the way for further investigations about how the brain interprets different artificial feedback strategies and for the development of fully implantable sensory-enhanced leg neuroprostheses, which could drastically ameliorate life quality in people with disability.

Disorganization of a hole tone feedback loop by an axisymmetric obstacle on a downstream end plate

2014 ◽  
Vol 757 ◽  
pp. 908-942 ◽  
Author(s):  
K. Matsuura ◽  
M. Nakano
Keyword(s):  
Nozzle Exit ◽  
Passive Control ◽  
Control Method ◽  
Three Dimensional ◽  
Acoustic Power ◽  
Shear Layers ◽  
Mean Velocity ◽  
End Plate ◽  
Air Jet ◽  
Practical Engineering

AbstractThis study investigates the suppression of the sound produced when a jet, issued from a circular nozzle or hole in a plate, goes through a similar hole in a second plate. The sound, known as a hole tone, is encountered in many practical engineering situations. The mean velocity of the air jet $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}u_0$ was $6\text {--}12\ \mathrm{m}\ {\mathrm{s}}^{-1}$. The nozzle and the end plate hole both had a diameter of 51 mm, and the impingement length $L_{im}$ between the nozzle and the end plate was 50–90 mm. We propose a novel passive control method of suppressing the tone with an axisymmetric obstacle on the end plate. We find that the effect of the obstacle is well described by the combination ($W/L_{im}$, $h$) where $W$ is the distance from the edge of the end plate hole to the inner wall of the obstacle, and $h$ is the obstacle height. The tone is suppressed when backflows from the obstacle affect the jet shear layers near the nozzle exit. We do a direct sound computation for a typical case where the tone is successfully suppressed. Axisymmetric uniformity observed in the uncontrolled case is broken almost completely in the controlled case. The destruction is maintained by the process in which three-dimensional vortices in the jet shear layers convect downstream, interact with the obstacle and recursively disturb the jet flow from the nozzle exit. While regions near the edge of the end plate hole are responsible for producing the sound in the controlled case as well as in the uncontrolled case, acoustic power in the controlled case is much lower than in the uncontrolled case because of the disorganized state.

scholarly journals An Investigation into a Gear-Based Knee Joint Designed for Lower Limb Prosthesis

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
M. S. H. Bhuiyan ◽  
I. A. Choudhury ◽  
M. Dahari ◽  
Y. Nukman ◽  
S. Z. Dawal
Keyword(s):  
Knee Joint ◽  
Motion Analysis ◽  
Maximum Stress ◽  
Real Data ◽  
Fe Analysis ◽  
Knee Prostheses ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Lower Limb Prosthesis ◽  
Limb Prosthesis

A gear-based knee joint is designed to improve the performance of mechanical-type above-knee prostheses. The gear set with the help of some bracing, and bracket arrangement, is used to enable the prosthesis to follow the residual limb movement. The motion analysis and finite-element analysis (FEA) of knee joint components are carried out to assess the feasibility of the design. The maximum stress of 29.74 MPa and maximum strain of 2.393e−004 are obtained in the gear, whereas the maximum displacement of 7.975 mm occurred in the stopper of the knee arrangement. The factor of safety of 3.5 obtained from the FE analysis indicated no possibility of design failure. The results obtained from the FE analysis are then compared with the real data obtained from the literature for a similar subject. The pattern of motion analysis results has shown a great resemblance with the gait cycle of a healthy biological limb.

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