Cartan connection applied to dynamic calculation in robotics

2018 ◽  
Vol 40 (8) ◽  
Author(s):  
Diego Colón
Keyword(s):  
Cartan Connection ◽  
Dynamic Calculation

scholarly journals The Influence of an Integration Time Step on Dynamic Calculation of a Vehicle-Track-Bridge under High-Speed Railway

Mathematics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 431
Author(s):  
Junjie Ye ◽  
Hao Sun
Keyword(s):  
High Speed ◽  
Coupled Model ◽  
Short Wave ◽  
Integration Time ◽  
Vertical Acceleration ◽  
Dynamic Calculation ◽  
Time Step ◽  
High Speed Railway ◽  
Track Irregularity ◽  
Track Bridge

In order to study the influence of an integration time step on dynamic calculation of a vehicle-track-bridge under high-speed railway, a vehicle-track-bridge (VTB) coupled model is established. The influence of the integration time step on calculation accuracy and calculation stability under different speeds or different track regularity states is studied. The influence of the track irregularity on the integration time step is further analyzed by using the spectral characteristic of sensitive wavelength. According to the results, the disparity among the effect of the integration time step on the calculation accuracy of the VTB coupled model at different speeds is very small. Higher speed requires a smaller integration time step to keep the calculation results stable. The effect of the integration time step on the calculation stability of the maximum vertical acceleration of each component at different speeds is somewhat different, and the mechanism of the effect of the integration time step on the calculation stability of the vehicle-track-bridge coupled system is that corresponding displacement at the integration time step is different. The calculation deviation of the maximum vertical acceleration of the car body, wheel-sets and bridge under the track short wave irregularity state are greatly increased compared with that without track irregularity. The maximum vertical acceleration of wheel-sets, rails, track slabs and the bridge under the track short wave irregularity state all show a significant declining trend. The larger the vibration frequency is, the smaller the range of integration time step is for dynamic calculation.

scholarly journals Teleparallel gravity as a gauge theory: Coupling to matter using the Cartan connection

2021 ◽  
Vol 103 (4) ◽  
Author(s):  
E. Huguet ◽  
M. Le Delliou ◽  
M. Fontanini ◽  
Z.-C. Lin
Keyword(s):  
Gauge Theory ◽  
Teleparallel Gravity ◽  
Cartan Connection

Design of a Counterweight Walker Active Therapeutic Movement Rehabilitation Rig

2013 ◽  
Author(s):  
Israel Aguilera Navarrete ◽  
Alejandro A. Lozano Guzmán
Keyword(s):  
Modular Design ◽  
Design Concept ◽  
Walking Ability ◽  
Mechanical Device ◽  
Dynamic Calculation ◽  
Client Needs ◽  
Walking Aid

According to INEGI (National Institute for Statistics and Geography), in 2004 there were around 730,000 people in Mexico with the need of some kind of mechanical aid to regain ability to walk. Support equipment for regaining the ability to walk normally is manufactured outside of Mexico. This equipment is complex and very expensive. In this work, the design of a walking ability rehabilitation aid is presented. This work is carried out applying the modular design concept. This ensures that all client needs are fulfilled by the resultant product, and that these needs are measurable and controllable. Basic idea behind this design is supporting part of patient’s weight and that of an exoskeleton on a mechanical device. Basic kinematics and dynamic calculation are presented, as well as simulations results. This information shows the feasibility of building and operating this rehabilitation walking aid.

Thermal Hydraulic Analysis of Severe Accident in PFBR

2010 ◽  
Author(s):  
K. Velusamy ◽  
P. Chellapandi ◽  
G. R. Raviprasan ◽  
P. Selvaraj ◽  
S. C. Chetal
Keyword(s):  
Atmospheric Pressure ◽  
Fluid Dynamic ◽  
Hydraulic Modeling ◽  
Severe Accident ◽  
Maximum Temperature ◽  
Maximum Pressure ◽  
Dynamic Calculation ◽  
Thermal Hydraulic Modeling ◽  
Thermal Hydraulic Analysis ◽  
Design Pressure

During a core disruptive accident (CDA), the amount of primary sodium that can be released to Reactor Containment Building (RCB) in Prototype Fast Breeder Reactor (PFBR) is estimated to be 350 kg/s, by a transient fluid dynamic calculation. The pressure and temperature evolutions inside RCB, due to consequent sodium fire have been estimated by a constant burning rate model, accounting for heat absorption by RCB wall, assuming RCB isolation based on area gamma monitors. The maximum pressure developed is 7000 Pa. In case RCB isolation is delayed, then the final pressure inside RCB reduces below atmospheric pressure due to cooling of RCB air. The negative pressure that can be developed is estimated by dynamic thermal hydraulic modeling of RCB air / wall to be −3500 Pa. These investigations were useful to arrive at the RCB design pressure. Following CDA, RCB is isolated for 40 days. During this period, the heat added to RCB is dissipated to atmosphere only by natural convection. Considering all the possible routes of heat addition to RCB, evolution of RCB wall temperature has been predicted using HEATING5 code. It is established that the maximum temperature in RCB wall is less than the permissible value.

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