Semi-Passive Walk and Active Walk by One Bipedal Robot: Mechanism, Control and Parameter Identification

2020 ◽  
Vol 17 (02) ◽  
pp. 2050012
Author(s):  
Shintaro Noda ◽  
Fumihito Sugai ◽  
Kunio Kojima ◽  
Kim-Ngoc-Khanh Nguyen ◽  
Yohei Kakiuchi ◽  
...  
Keyword(s):  
Parameter Identification ◽  
Optimization Technique ◽  
Environmental Parameters ◽  
High Strength ◽  
The Body ◽  
Bipedal Robot ◽  
Passive Joint ◽  
Passive Walking ◽  
Joint Dynamics ◽  
Mechanism Control

We developed a bipedal robot equipped with brake and clutch mechanisms to change the number of active and passive joints, thereby enabling various types of movements including normal active walking using 12-dof joints, under-actuated walking using brake, and passive-based walking using clutch and passive joints. In this paper, we describe three technologies to achieve the proposed system and show experimental results on active and semi-passive walking. The first technology comprises a small and high-strength clutch mechanism to sustain the massive weight of life-sized robots using actuators for joint and dog clutch control. The second technology comprises a walking controller using a simulation-based optimization technique to consider passive joint dynamics instead of depending on the inverse kinematics problem, thereby enabling the control of the under-actuated leg. The last technology is model parameter identification to achieve unstable passive-based walking in real-world considering the body as well as environmental parameters such as ground slope. To the best of our knowledge, the proposed robot is the first to achieve both active and passive-based walking using a bipedal body. This enables the implementation of the passive-walking technology to active-joint robots and expands the application possibility of passive joint for bipedal robots.

Parameter identification for load frequency control using fuzzy FOPID in power system

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ram Kumar ◽  
Afzal Sikander
Keyword(s):  
Fuzzy Logic ◽  
Power System ◽  
Parameter Identification ◽  
Fractional Order ◽  
Optimization Technique ◽  
Load Frequency Control ◽  
Control Law ◽  
Content Type ◽  
Load Frequency ◽  
Frequency Controller

Purpose This paper aims to suggest the parameter identification of load frequency controller in power system. Design/methodology/approach The suggested control approach is established using fuzzy logic to design a fractional order load frequency controller. A new suitable control law is developed using fuzzy logic, and based on this developed control law, the unknown parameters of the fractional order proportional integral derivative (FOPID) controller are derived using an optimization technique, which is being used by minimizing the integral square error. In addition, to confirm the effectiveness of the proposed control design approach, numerous simulation tests were carried out on an actual single-area power system. Findings The obtained results reveal the superiority of the suggested controller as compared to the recently developed controllers with regard to time response specifications and quantifiable indicators. Additionally, the potential of the suggested controller is also observed by improving the load disturbance rejections under plant parametric uncertainty. Originality/value To the best of the authors’ knowledge, the work is not published anywhere else.

Fabrication of α-TCP, HAp Functionally Graded Porous Beads

2008 ◽  
Vol 57 ◽  
pp. 135-138
Author(s):  
Yuji Kajihata ◽  
Teruo Asaoka ◽  
Katsuko S. Furukawa ◽  
Takashi Ushida ◽  
T. Tateishi
Keyword(s):  
Surface Layer ◽  
High Strength ◽  
Functionally Graded ◽  
The Body ◽  
Acid Solutions ◽  
Bioactive Material ◽  
Hydrolytic Reaction ◽  
Rate Of Absorption ◽  
Porous Beads ◽  
Good Cell

HAp (Hydroxyapatite) and α-TCP (alpha tribasic calcium phosphate) are non-toxic to human cells and, thus, have been studied for applications as biomaterials. HAp is a bioactive material that is not readily absorbed by the body; it offers both high strength and better tissueadhesive properties than α-TCP. In contrast, α-TCP is highly bioabsorbable; it is quickly absorbed by the body, and, therefore, for example, disappears before bone is completely replaced. If porous beads could be fabricated that would take advantage of the useful properties of α-TCP and HAp, they could be used as excellent scaffolds for cultivating cells. In the present study, ceramic beads with α-TCP at the center were fabricated and coated with a functionally graded film of HAp. A scaffold based on this configuration would be expected to have the following characteristics: good cell adhesion; strong beads; and a rate of absorption into the body that would be easy to control. In addition, to accelerate the formation of porous structure, some acid solutions were used to dissolve the beads surface layer and to penetrate pores toward inside of the bead. HAp formation through hydrolytic reaction seemed to be promoted by these acid solutions.

Occupational Hot Exposures: Body Physiology and An Approach to Numerical Assessment

1989 ◽  
Vol 203 (3) ◽  
pp. 133-141 ◽  
Author(s):  
R C McLean ◽  
G H Galbraith ◽  
D Stewart
Keyword(s):  
Heat Stress ◽  
Working Conditions ◽  
Heat Balance ◽  
Energy Exchange ◽  
Environmental Parameters ◽  
The Body ◽  
Assessment Procedure ◽  
Exchange Processes ◽  
Numerical Assessment ◽  
Physiological Reactions

This paper summarizes the factors which influence the energy exchange processes between an individual and his surroundings and the mechanisms by which the body attempts to maintain itself in a heat balance situation. Thereafter, the important physiological reactions to hot working conditions are described and, on this basis, a numerical assessment procedure is proposed. Examples are given of the use of this method in investigating the possibility of heat stress and estimating the time for which an acclimatized worker can safely be exposed in such circumstances. An increase in the permissible exposure time through a manipulation of the environmental parameters is also considered.

Relationship between Microstructure and Mechanical Properties in Q&P-Steels

2016 ◽  
Vol 879 ◽  
pp. 1933-1938 ◽  
Author(s):  
Richard G. Thiessen ◽  
Georg Paul ◽  
Roland Sebald
Keyword(s):  
Mechanical Properties ◽  
Dual Phase Steel ◽  
High Strength Steels ◽  
High Strength ◽  
The Body ◽  
Advanced High Strength Steels ◽  
Passenger Safety ◽  
Back Scattering ◽  
Body In White ◽  
Expected Increase

Third-Generation advanced high strength steels are being developed with the goal of reducing the body-in-white weight while simultaneously increasing passenger safety. This requires not only the expected increase in strength and elongation, but also improved local formability. Optimizing elongation and formability were often contradictory goals in dual-phase steel developments. Recent results have shown that so-called "quench and partitioning" (Q&P) concepts can satisfy both requirements [1]. Many Q&P-concepts have been studied at thyssenkrupp Steel Europe. Thorough investigation of the microstructure has revealed relationships between features such as the amount, morphology and chemical stability of the retained austenite and the obtained mechanical properties. An evaluation of the lattice strain by means of electron-back-scattering-diffraction has also yielded a correlation to the obtained formability. The aim of this work is to present the interconnection between these microstructural features and propose hypotheses for the explanation of how these features influence the macroscopically observed properties.

scholarly journals Cerebral hemispheres – cerebellum – kidney interaction in patients with acute cerebral ischemia

2021 ◽  
Vol 26 (1) ◽  
pp. 90-98
Author(s):  
O.M. Kononets ◽  
O.V. Tkachenko ◽  
O.O. Kamenetska
Keyword(s):  
Nervous System ◽  
Ischemic Stroke ◽  
Brain Magnetic Resonance Imaging ◽  
Environmental Parameters ◽  
The Body ◽  
Electrolyte Balance ◽  
Vector Correlation ◽  
Vertebrobasilar System ◽  
Acute Cerebral Ischemia ◽  
The Right

The nervous system, in particular the autonomic one, is well known to constantly regulate the internal functioning of the body, adapting it to changeable external and internal environmental parameters. In particular, there is a close multiple-vector correlation between the nervous system and the kidneys. The aim of this study was to specify the mechanisms, clinical and paraclinical characteristics of the concomitant lesions of the nervous system and the kidneys in patients with acute stroke. This paper presents the case report of 215 patients, aged 70 ± 8.44, who suffered from ischemic stroke. Among them, we examined 144 women and 71 men. The patients underwent a comprehensive examination, including a detailed clinical and neurological check-up (evaluating the patients’ condition severity with the National Institutes of Health Stroke Scale (NIHSS) and the Barthel index on admission and on the 21st day of the disease), laboratory analysis (electrolyte balance, nitrogen metabolism (on admission and on the 21st day of the disease) and instrumental examination (CT scan of the brain, the follow-up brain magnetic resonance imaging). The statistical methods were used to analyze the data. In the 1st day of the disease, all the surveyed patients with right hemispheric carotid stroke and the overwhelming majority of the patients with left hemispheric carotid stroke and ischemic stroke in the vertebrobasilar system had cerebral renal syndrome, represented by renal concentration-filtration dysfunction, accompanied by the reduced glomerular filtration rate. A reliable relationship was found between the renal concentration and filtration function and the right hemispheric ischemic focus in patients with ischemic stroke, the characteristics are to be specified.

Vibrations and spasticity

2021 ◽  
pp. 76-84
Author(s):  
Supplizi Marco ◽  
Barassi Giovanni ◽  
Visciano Christian Pasquale ◽  
Zincani Vlentina ◽  
Di Iulio Antonell ◽  
...  
Keyword(s):  
Experimental Study ◽  
Trigger Points ◽  
The Body ◽  
Mechanical Vibrations ◽  
Passive Joint ◽  
Reflex Pathways ◽  
Good Improvement ◽  
Neurological Pathology ◽  
Ashworth Scale ◽  
Joint Evaluation

This experimental study aims to evaluate and validate the effectiveness of the proposed application method in the use of "focused mechanical vibrations" for the treatment of muscle spasticity. The basic concept of this study is that in spasticity, by specifically stimulating some clearly identifiable trigger points of the body, better results are obtained; in fact, with the localized mechanical-sound vibrations, by positioning the handpiece for the treatment on those specific points, immediate generalized relaxation of the entire spastic muscle is obtained through reflex pathways. To evaluate this operative reality we treated 5 subjects affected by neurological pathology with spasticity and at T0 time (before treatment) and at T1 time (immediately after treatment), they were assessed with Ashworth Scale, Passive joint evaluation, Evaluation of active motility, Test of Bahkta (for non-functioning hand), surface electromyography The subjects were treated with a 120Hz vibratory therapy handpiece for a total time of 15 minutes The data showed us a clear improvement of the parameters lost in the exam, in the less serious patients and a good improvement also in the most serious subjects.

scholarly journals An Overview on the Tribological Performance of Titanium Alloys with Surface Modifications for Biomedical Applications

Lubricants ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 65 ◽  
Author(s):  
Kaur ◽  
Ghadirinejad ◽  
Oskouei
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Titanium Alloys ◽  
Weight Ratio ◽  
High Strength ◽  
Surface Modifications ◽  
Tribological Performance ◽  
The Body ◽  
High Wear Resistance ◽  
Medical Implants

The need for metallic biomaterials will always remain high with their growing demand in joint replacement in the aging population. This creates need for the market and researchers to focus on the development and advancement of the biometals. Desirable characteristics such as excellent biocompatibility, high strength, comparable elastic modulus with bones, good corrosion resistance, and high wear resistance are the significant issues to address for medical implants, particularly load-bearing orthopedic implants. The widespread use of titanium alloys in biomedical implants create a big demand to identify and assess the behavior and performance of these alloys when used in the human body. Being the most commonly used metal alloy in the fabrication of medical implants, mainly because of its good biocompatibility and corrosion resistance together with its high strength to weight ratio, the tribological behavior of these alloys have always been an important subject for study. Titanium alloys with improved wear resistance will of course enhance the longevity of implants in the body. In this paper, tribological performance of titanium alloys (medical grades) is reviewed. Various methods of surface modifications employed for titanium alloys are also discussed in the context of wear behavior.

Multi-Objective Optimization on Drilling of Titanium Alloy (Ti6Al4V)

2013 ◽  
Vol 763 ◽  
pp. 29-49 ◽  
Author(s):  
A. Prabukarthi ◽  
V. Krishnaraj ◽  
M. Senthil Kumar
Keyword(s):  
Titanium Alloy ◽  
Thrust Force ◽  
Optimization Technique ◽  
Weight Ratio ◽  
High Strength ◽  
Hole Diameter ◽  
Machining Process ◽  
Multi Objective ◽  
Titanium Alloy Ti6al4v ◽  
Exit Burr

Titanium alloys present superior properties like resistance to corrosion, high strength to weight ratio etc, but possess poor machinability. Titanium alloy Ti-6Al-4V is the most commonly used titanium alloy in aerospace and medical device industries. Titanium and its alloys are notorious for their poor thermal properties and are classified as difficult-to-machine materials. Drilling is an important machining process since it is involved in nearly all titanium applications. It is desirable to develop optimized drilling processes for Ti and improve the hole characteristics such as hole diameter, circularity and exit burr of currently available processes. Due to the low machinability of the alloys under study, selecting the machining conditions and parameters is crucial. The range of spindle speed and feed rate, which provide a satisfactory tool life, is very limited. The hole quality (hole diameter and circularity), thrust force, torque and exit burr were evaluated at various spindle speeds, feed rates combinations. The optimized parameter is chosen using the multi-objective weighted sum optimization technique.

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