Model for the Continuous Description of Motion and Position

1981 ◽  
Vol 53 (1) ◽  
pp. 43-48
Author(s):  
Guillermo Solano-Flores
Keyword(s):  
Representative Point ◽  
Continuous Representation ◽  
Reference Axis ◽  
Continuous Description ◽  
Cyclical Motion ◽  
Selection Of ◽  
Bodily Part ◽  
Representation Of Time

A model is suggested for the continuous description of cyclical motion. The model is an application of the sinus equation and derives from the selection of a representative point of a bodily part for which movement is to be described, the identification of a reference axis, and the continuous representation of time. Although restricted to cyclical motion, the model seems useful for describing many behaviors of quite different species by means of the same descriptive elements.

scholarly journals Zero-Width Quasi-Sliding Mode Band in the Presence of Non-Matched Uncertainties

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3011
Author(s):  
Paweł Latosiński ◽  
Andrzej Bartoszewicz
Keyword(s):  
Sliding Mode Control ◽  
Discrete Time ◽  
Sliding Mode ◽  
Control Strategies ◽  
Relative Degree ◽  
Band Width ◽  
Representative Point ◽  
Mode Control ◽  
Sliding Motion ◽  
Selection Of

Sliding mode control strategies are well known for ensuring robustness of the system with respect to disturbance and model uncertainties. For continuous-time plants, they achieve this property by confining the system state to a particular hyperplane in the state space. Contrary to this, discrete-time sliding mode control (DSMC) strategies only drive the system representative point to a certain vicinity of that hyperplane. In established literature on DSMC, the width of this vicinity has always been strictly greater than zero in the presence of uncertainties. Thus, ideal sliding motion was considered impossible for discrete-time systems. In this paper, a new approach to DSMC design is presented with the aim of driving the system representative point exactly onto the sliding hyperplane even in the presence of uncertainties. As a result, the quasi-sliding mode band width is effectively reduced to zero and ideal discrete-time sliding motion is ensured. This is achieved with the proper selection of the sliding hyperplane, using the unique properties of relative degree two sliding variables. It is further demonstrated that, even in cases where selection of a relative degree two sliding variable is impossible, one can use the proposed technique to significantly reduce the quasi-sliding mode band width.

scholarly journals Selection of Reference Axis for Distal Femoral Rotation in TKA: A Literature Review

2018 ◽  
Vol 8 (04) ◽  
Author(s):  
Ravikant Kamal
Keyword(s):  
Aseptic Loosening ◽  
Rotational Alignment ◽  
Rotational Axis ◽  
Preoperative Pain ◽  
Gap Balancing ◽  
Component Placement ◽  
Reference Axis ◽  
Number Of Patients ◽  
Measured Resection ◽  
Selection Of

Total knee arthroplasty (TKA) is widely accepted and standard surgical procedure for osteoarthritis. Most patients are able to recover their preoperative pain completely and achieve a good range of motions to perform daily tasks after TKA. However, there is a number of patients who remained unsatisfied with the result after TKA and often complain pain in performing daily task. Exploring reason behind post-operative pain and failure of TKA; researchers had found that in 31.2% of these cases; failure is due to aseptic loosening. Aseptic loosening is closely related to improper component placement. Orienting component in the axial direction is critical for proper outcome of TKA. Measured resection and gap balancing are two methods used for rotational alignment of component. Studies have shown that the measured resection technique has an advantage over gap balancing. However, the outcome of measured resection technique depends on the proper selection of reference axis. Transepicondyle axis, Whiteside line and Posterior condyle line are mostly used for setting the component rotation in TEA. All three rotational axis has its own advantages and pitfalls, therefore selection of reference should be based upon knee bone morphology and diseased condition. Malalignment of component placement in the axial plane may cause patella maltracking, anterior knee pain, aseptic loosening and also it could be one of the reasons behind TKA revision. The Success of rotational alignment depends upon proper preoperative planning and accurately selection of landmarks involved in creating axis. In this review paper, Pros and cons of reference axis are discussed individually and their correlations with each other are explored based on existing literature.

Cross-coupled PID control in position domain for contour tracking

Robotica ◽  
2014 ◽  
Vol 33 (6) ◽  
pp. 1351-1374 ◽  
Author(s):  
P. R. Ouyang ◽  
T. Dam ◽  
V. Pano
Keyword(s):  
Time Domain ◽  
Pid Control ◽  
Numerical Control ◽  
Tracking Performance ◽  
Contour Tracking ◽  
Cnc Machine ◽  
Reference Axis ◽  
Equivalent Time ◽  
Random Disturbances ◽  
Selection Of

SUMMARYAccurate contour tracking is one of the main tasks in modern manufacturing processes. By considering coupling effects among multiple axes, this paper proposes a cross-coupled proportional-integral-derivative (PID) control developed in position domain, and the controller is applied to a multi-axis computer numerical control (CNC) machine for contour tracking performance improvement. Stability analysis is conducted for the developed position domain cross-coupled PID control using the Lyapunov method, and guidelines for the selection of control gains are provided. The contour tracking performance are improved compared to an equivalent time domain controller, since the reference axis in position domain control does not contribute any error to the overall contouring error of the system. Simulation results demonstrate the effectiveness of cross-coupled PID position domain control for both linear and circular contour tracking, and prove the robustness of the controller to deal with random disturbances. It also shows that position domain cross-coupled PID control provides better contour tracking performance over position domain PID control and the equivalent time domain PID control.

scholarly journals Pemberitaan Kerukunan Umat Beragama: Analisis Pesan Media

2017 ◽  
Vol 1 (1) ◽  
pp. 17-30 ◽  
Author(s):  
Farhan Farhan
Keyword(s):  
Social Media ◽  
Data Collection ◽  
Media Coverage ◽  
Visual Media ◽  
Religious Communities ◽  
Religious Leaders ◽  
Continuous Representation ◽  
Qualitative Descriptive ◽  
The Media ◽  
Selection Of

This paper discusses the harmony of religious communities in Indonesia through the online mass media coverage represents the reality of tri harmony of religion. The preaching of religious harmony is approached with the theory of communication through media texts. Data collection is done through online observation on the media. The media in question is a youtube audio-visual media, online print media (Metrotvnews.com, Detik.news, Republika.ac.id, Antaranews.com) that preach harmony between religious and publicized between April and June 2016. The identified data is then analyzed and presented in qualitative descriptive. The results of research are; first; social media displays news about religious tolerance as a continuous representation of the religious harmony trilogy. Second; The selection of themes or titles of news between social media represent the significant and synergic and dynamic roles of government and religious leaders between the central and regional levels. Third; Messages through their preaching are potentially 'antagonistic' and 'ambiguous' when confronted with a report based on a majority-minority, and / or peace-conflict element.

Cognitive gadgets and cognitive priors

2019 ◽  
Vol 42 ◽  
Author(s):  
Gian Domenico Iannetti ◽  
Giorgio Vallortigara
Keyword(s):  
Cognitive Neuroscience ◽  
Selection Of

Abstract Some of the foundations of Heyes’ radical reasoning seem to be based on a fractional selection of available evidence. Using an ethological perspective, we argue against Heyes’ rapid dismissal of innate cognitive instincts. Heyes’ use of fMRI studies of literacy to claim that culture assembles pieces of mental technology seems an example of incorrect reverse inferences and overlap theories pervasive in cognitive neuroscience.

Note on Selection of Coordinate Systems for Geodynamics

1975 ◽  
Vol 26 ◽  
pp. 395-407
Author(s):  
S. Henriksen
Keyword(s):  
Sea Level ◽  
The Other ◽  
Coordinate Systems ◽  
Mean Sea Level ◽  
The Earth ◽  
The One ◽  
Static Systems ◽  
Selection Of

The first question to be answered, in seeking coordinate systems for geodynamics, is: what is geodynamics? The answer is, of course, that geodynamics is that part of geophysics which is concerned with movements of the Earth, as opposed to geostatics which is the physics of the stationary Earth. But as far as we know, there is no stationary Earth – epur sic monere. So geodynamics is actually coextensive with geophysics, and coordinate systems suitable for the one should be suitable for the other. At the present time, there are not many coordinate systems, if any, that can be identified with a static Earth. Certainly the only coordinate of aeronomic (atmospheric) interest is the height, and this is usually either as geodynamic height or as pressure. In oceanology, the most important coordinate is depth, and this, like heights in the atmosphere, is expressed as metric depth from mean sea level, as geodynamic depth, or as pressure. Only for the earth do we find “static” systems in use, ana even here there is real question as to whether the systems are dynamic or static. So it would seem that our answer to the question, of what kind, of coordinate systems are we seeking, must be that we are looking for the same systems as are used in geophysics, and these systems are dynamic in nature already – that is, their definition involvestime.

Measurements of the Cape Astrometric Survey of the Southern Hemisphere

1978 ◽  
Vol 48 ◽  
pp. 515-521
Author(s):  
W. Nicholson
Keyword(s):  
Southern Hemisphere ◽  
Automatic Measuring ◽  
Measuring Machine ◽  
Final Selection ◽  
Selection Of

SummaryA routine has been developed for the processing of the 5820 plates of the survey. The plates are measured on the automatic measuring machine, GALAXY, and the measures are subsequently processed by computer, to edit and then refer them to the SAO catalogue. A start has been made on measuring the plates, but the final selection of stars to be made is still a matter for discussion.

Application of Improved Voltage Compensation in the SEM to Imaging of Organic Materials

1973 ◽  
Vol 31 ◽  
pp. 444-445
Author(s):  
P.J. Killingworth ◽  
M. Warren
Keyword(s):  
Electron Beam ◽  
Organic Materials ◽  
Operating Parameters ◽  
Low Density ◽  
Beam Diameter ◽  
Incident Electron Beam ◽  
Specimen Material ◽  
Voltage Compensation ◽  
Selection Of ◽  
Scanning Electron

Ultimate resolution in the scanning electron microscope is determined not only by the diameter of the incident electron beam, but by interaction of that beam with the specimen material. Generally, while minimum beam diameter diminishes with increasing voltage, due to the reduced effect of aberration component and magnetic interference, the excited volume within the sample increases with electron energy. Thus, for any given material and imaging signal, there is an optimum volt age to achieve best resolution.In the case of organic materials, which are in general of low density and electric ally non-conducting; and may in addition be susceptible to radiation and heat damage, the selection of correct operating parameters is extremely critical and is achiev ed by interative adjustment.

Selection and Preparation of Specific Tissue Regions For Tem Using Large Epoxy-Embedded Blocks

1973 ◽  
Vol 31 ◽  
pp. 324-325 ◽  
Author(s):  
P. M. Lowrie ◽  
W. S. Tyler
Keyword(s):  
Electron Microscopy ◽  
Anatomical Structures ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Microscopic Evaluation ◽  
Embedded Blocks ◽  
Specific Tissue ◽  
Definition Of ◽  
Areas Of Interest ◽  
Selection Of

The importance of examining stained 1 to 2μ plastic sections by light microscopy has long been recognized, both for increased definition of many histologic features and for selection of specimen samples to be used in ultrastructural studies. Selection of specimens with specific orien ation relative to anatomical structures becomes of critical importance in ultrastructural investigations of organs such as the lung. The uantity of blocks necessary to locate special areas of interest by random sampling is large, however, and the method is lacking in precision. Several methods have been described for selection of specific areas for electron microscopy using light microscopic evaluation of paraffin, epoxy-infiltrated, or epoxy-embedded large blocks from which thick sections were cut. Selected areas from these thick sections were subsequently removed and re-embedded or attached to blank precasted blocks and resectioned for transmission electron microscopy (TEM).

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