scholarly journals A Power-Assisted Cart with the Optimal Assistance Ratio and Disturbance Observer-Based Methods for Walking Assistance Applications

2021 ◽  
Vol 11 (3) ◽  
pp. 1079
Author(s):  
Xianglong Wan ◽  
Jiaxin Ma ◽  
Yichi Zhang ◽  
Takahiro Endo ◽  
Fumitoshi Matsuno
Keyword(s):  
Healthy Subjects ◽  
Disturbance Observer ◽  
The Elderly ◽  
Operational Efficiency ◽  
Motor Output ◽  
Experimental Results ◽  
Control Methods ◽  
Road Surfaces

In this paper, we propose two control methods for driving a power-assisted cart made for walking assistance for the elderly. The optimal assistance ratio (OAR) and disturbance observer-based (DOB) methods properly adjust the motor output of the cart with high operational efficiency in response to changes in the environment. Healthy subjects walked with the cart on several road surfaces under various conditions, and the experimental results indicate the high operational efficiency of the two proposed methods. Meanwhile, their drawbacks are also discussed herein. The two methods can be used separately or combined according to the application. The OAR method is more suitable for indoor use, while the DOB method is applicable for outdoor applications. Combining these two methods could overcome the mentioned drawbacks.

Robust Impedance Control for Robot Manipulator

1991 ◽  
Vol 3 (6) ◽  
pp. 470-474
Author(s):  
Yoshiharu Nishida ◽  
◽  
Takashi Harada ◽  
Nobuaki Imamura ◽  
Nobuo Kimura
Keyword(s):  
Disturbance Observer ◽  
Robot Manipulator ◽  
Impedance Control ◽  
Joint Space ◽  
Experimental Results ◽  
Control Methods ◽  
Robust Controller ◽  
End Effector ◽  
Cartesian Space ◽  
Modeling Errors

In most robust impedance control methods, error factors such as disturbances and modeling errors in the joint space are dealt with. However, the dynamics for an end effector of the manipulator in the Cartesian space is more important than that of the manipulator in the joint space. In this paper, error factors are described in the Cartesian space, and the influence of these factors on the dynamics of the end-effector are considered. A robust controller is designed using either feedback of impedance error or a disturbance observer based on the Cartesian space, and its effectiveness is confirmed through experimental results.

Suppression of the transcallosal motor output: a transcranial magnetic stimulation study in healthy subjects

2004 ◽  
Vol 158 (2) ◽  
Author(s):  
Carlo Trompetto ◽  
Marco Bove ◽  
Lucio Marinelli ◽  
Laura Avanzino ◽  
Alessandro Buccolieri ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Healthy Subjects ◽  
Magnetic Stimulation ◽  
Motor Output

Initial Experiments on the Control of a Mobile Tower Crane

2007 ◽  
Author(s):  
Joshua Vaughan ◽  
William Singhose ◽  
Paulo Debenest ◽  
Edwardo Fukushima ◽  
Shigeo Hirose
Keyword(s):  
Theoretical Model ◽  
Material Handling ◽  
Operational Efficiency ◽  
Experimental Results ◽  
Input Shaping ◽  
Oscillatory Dynamics ◽  
Tower Crane ◽  
Operational Capabilities ◽  
The World

Cranes are used extensively throughout the world in a wide variety of construction and material handling applications. The speed at which these cranes are operated is limited by payload oscillation. Input shaping is one method that reduces this oscillation, allowing higher speeds and improving operational efficiency. Another method to improve the operational capabilities of cranes is to allow base motion. This paper presents initial experimental results from a portable, mobile tower crane. A theoretical model of the crane is presented and experimentally verified. The oscillatory dynamics of the crane are highlighted and controllers to combat these unwanted dynamics are presented.

Physics-Based Friction Model With Potential Application in Numerical Models for Tire-Road Traction

2017 ◽  
Author(s):  
Anahita Emami ◽  
Seyedmeysam Khaleghian ◽  
Chuang Su ◽  
Saied Taheri
Keyword(s):  
Theoretical Model ◽  
Friction Coefficient ◽  
Numerical Models ◽  
Surface Profile ◽  
Viscoelastic Behavior ◽  
Numerical Results ◽  
Experimental Results ◽  
Real Contact Area ◽  
Computer Algorithms ◽  
Road Surfaces

Good understanding of friction in tire-road interaction is of critical importance for vehicle dynamic control systems. Most of the friction models proposed to describe the friction coefficient between tire-treads and road surfaces have been developed based on empirical or semi-empirical relations that are not able to include many effective parameters involved in the tire-road interactions. Therefore, these models are just useful in limited conditions similar to the experiments, and do not accurately represent tire-road traction in numerical tire models. However, in last two decades, a few theoretical models have been developed to calculate the tire-road friction coefficient theoretically by considering both viscoelastic behavior of tire tread compounds and multi-scale interactions between tire treads and rough road surfaces. In this article, a novel physics-based model proposed by Persson has been investigated and used to develop computer algorithms for calculation of sliding friction coefficient between a tire tread compound and a rough substrate. The viscoelastic behavior of tread compound and the surface profile of rough counter surface are the inputs of this physics-based theoretical model. The numerical results of the model have been compared with the experimental results obtained from a dynamic friction tester designed and built in the Center for Tire Research (CenTire). Good agreement between numerical results of theoretical model and experimental results has been found at intermediate range of slip velocities considering the effect of adhesion and shearing in the real contact area in addition to hysteresis friction due to internal energy dissipation in the tire tread compound.

scholarly journals Absence of age and gender effects on the pharmacokinetics of a single 500-milligram oral dose of levofloxacin in healthy subjects.

1997 ◽  
Vol 41 (7) ◽  
pp. 1562-1565 ◽  
Author(s):  
S C Chien ◽  
A T Chow ◽  
J Natarajan ◽  
R R Williams ◽  
F A Wong ◽  
...  
Keyword(s):  
Renal Function ◽  
Healthy Subjects ◽  
Age Groups ◽  
The Elderly ◽  
Gender Effects ◽  
Pharmacokinetic Parameters ◽  
Age And Gender ◽  
Male And Female ◽  
Young Males ◽  
And Gender

The influence of age and gender on the pharmacokinetics of levofloxacin in healthy subjects receiving a single oral 500-mg dose of levofloxacin was investigated in this parallel design study. Six young males (aged 18 to 40 years), six elderly males (aged > or = 65 years), six young females (aged 18 to 40 years), and six elderly females (aged > or = 65 years) were enrolled and completed the study. The study reveals that the bioavailability (rate and extent) of levofloxacin was not affected by either age or gender. In both age (young and elderly) and gender (male and female) groups of subjects, peak concentrations in plasma were reached at approximately 1.5 h after dosing; renal clearance of levofloxacin accounted for approximately 77% of total body clearance, and approximately 76% of the administered dose was recovered unchanged in urine over the 36 h of collection. The apparent differences in the calculated pharmacokinetic parameters for levofloxacin between the age groups (young versus elderly) and between the gender groups (males versus females) could be explained by differences in renal function among the subjects. A single dose of 500 mg of levofloxacin administered orally to both young and old, male and female healthy subjects was found to be safe and well tolerated. As the differences in levofloxacin kinetics between the young and the elderly or the males and the females are limited and are mainly related to the renal function of the subjects, dose adjustment based on age or gender alone is not necessary.

scholarly journals Serological Analysis and Drug Resistance of Chlamydia pneumoniae and Mycoplasma pneumoniae in 4500 Healthy Subjects in Shenzhen, China

2017 ◽  
Vol 2017 ◽  
pp. 1-5
Author(s):  
Dong Du ◽  
Shuping Liao ◽  
Yan Wu ◽  
Yang Jiao ◽  
Di Wu ◽  
...  
Keyword(s):  
Mycoplasma Pneumoniae ◽  
Healthy Subjects ◽  
Chlamydia Pneumoniae ◽  
Venous Blood ◽  
The Elderly ◽  
Asymptomatic Infection ◽  
High Rate ◽  
Prevention Measures ◽  
Drug Resistant Strains ◽  
Relationship Of

Objective. To understand the prevalence and distribution of Chlamydia pneumoniae (CP) and Mycoplasma pneumoniae (MP) in the population and to provide a basis for the prevention and treatment of respiratory tract infection. Methods. This study included a total of 4500 healthy subjects who were given physical examination in Shenzhen People’s Hospital from January to December in 2016. Venous blood was drawn from people to detect the MP- and CP-specific IgG and IgM in the serum using chemiluminescence immunoassay (CLIA). The relationship of MP and CP infections with patient age, seasons, and percentage of infections was analyzed. Conclusion. CP and MP cause high rate of asymptomatic infection, which may be associated with the high incidence of CP and MP infection, especially in children and the elderly population. Therefore, the implementation of effective and practical prevention measures has become an urgent need. MP culture and drug sensitivity test should be performed as early as possible in patients with manifested MP infections in order to ensure timely and proper treatment and to reduce the emergence of drug-resistant strains.

Effects of Non-Rhythmical Paroxysmal Stimulation on EEG-EMG Coherence during Still Standing in Humans

2013 ◽  
Vol 749 ◽  
pp. 418-422
Author(s):  
Jian Feng Sui ◽  
Cristopher Young ◽  
Lin Hong Ji
Keyword(s):  
Cortical Neurons ◽  
Healthy Subjects ◽  
Tibialis Anterior ◽  
Surface Emg ◽  
Motor Output ◽  
Neuronal Oscillations ◽  
The Subject ◽  
Gastrocnemius Muscles ◽  
Electroencephalogram Eeg

In many previous studies, neuronal oscillations in humans under 1530 Hz activity have been observed, correlated with rhythmical motor output. In this present study, we observed the influence of non-rhythmical paroxysmal stimulation on cortical neurons by analyzing the coherence between electroencephalogram (EEG) and electromyogram (EMG). The non-rhythmical stimulation was performed by using this method that the braced force of the subjects one foot was released suddenly when the subject was standing still. The surface EMG signals from the tibialis anterior and the gastrocnemius muscles of 10 healthy subjects were recorded, and the cortical activities of contralateral cortical sensorimotor areas were also recorded simultaneously by EEG during the experiment. The data indicates that the range (10-25Hz) synchronization represents a state of the cortico-muscular network when the balance is broken which the braced force of subjects one foot is released suddenly.

The Active Control of Forced Vibration Produced by Arbitrary Disturbances

1985 ◽  
Vol 107 (1) ◽  
pp. 33-37 ◽  
Author(s):  
J. S. Burdess ◽  
A. V. Metcalfe
Keyword(s):  
Vibration Control ◽  
Active Control ◽  
Forced Vibration ◽  
Disturbance Observer ◽  
Degree Of Freedom ◽  
Experimental Results ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Impact Forces ◽  
Mass Spring

This paper considers the vibration control of a single degree of freedom mass-spring-damper system when subjected to an arbitrary, unmeasurable disturbance. The idea of a disturbance observer is introduced and it is shown how an estimate of the excitation can be derived and used to generate a control, which reduces the vibration. This control is shown to be robust with respect to the parameters describing the behavior of the system. Experimental results are presented which show the efficacy of the method when the system is excited by periodic, random, and impact forces. Comments are made on the application of the method.

Sign in / Sign up

Export Citation Format

Share Document