scholarly journals The Gantry as a Drive for a Horizontal Bike: Initial Investigation of Rotary Work

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Łukasz Bereś ◽  
Paweł Pyrzanowski
Keyword(s):  
Mathematical Analysis ◽  
Rotational Motion ◽  
Mechanical Energy ◽  
Gear Wheel ◽  
Static Tests ◽  
Initial Investigation ◽  
Full Rotation ◽  
Drive Systems ◽  
To Receive

The gantry drive (also, “the gantry”) is a mechanism that receives human-generated mechanical energy. The gantry used in a horizontal bike is a type of drive, and it is an alternative to a typical crankset. The purpose of this paper was to compare rotary work generated by the gantry and the crankset. The comparative criterion for the gantry and the crankset was work in rotational motion. The comparison was based on static tests; forces put into both drive systems were measured, and the rotary work was mathematically calculated. The forces put into the drive systems were measured for a man 177 cm tall and of 76 kg mass. To facilitate analysis and tests, the first gear wheel to receive force from the toothed rack (the gantry drive) was assumed to have the same radius as the crank (the crankset drive). Mathematical analysis performed for one full rotation (360°) of the first gear wheel and crankset showed that rotary work for the gantry was 2117.31 J and for the crankset 804.81 J. Ultimately, it was shown that the gantry can better receive mechanical energy from the human than the crankset. This means that a human will be less tired when riding a horizontal bike equipped with the gantry compared to a horizontal bike equipped with the crankset; assuming that in both cases, the bike speed is the same. Additionally, thanks to the use of the gantry drive in a horizontal bike, it is possible to achieve higher speeds compared to a horizontal bike equipped with the crankset.

scholarly journals A high efficiency pneumatic drive system using vane-type semi-rotary actuators

2021 ◽  
Vol 34 (3) ◽  
pp. 415-433
Author(s):  
Alfred Rufer
Keyword(s):  
Rotational Motion ◽  
High Efficiency ◽  
Mechanical Energy ◽  
Compressed Air ◽  
Energetic Efficiency ◽  
Pneumatic Drive ◽  
Mechanical Motion ◽  
Set Up ◽  
Energetic Performance ◽  
New System

A compressed air driven generator is proposed, where the pneumatic energy is converted into mechanical energy using two vane-type rotational actuators. The use of a second actuator with a higher displacement in order to produce a thermodynamic expansion allows to reach a better energetic efficiency in comparison to the classical operation of such actuators. The alternating movement of the angular actuators is transformed into a unidirectional rotational motion with the help of a mechanical motion rectifier. The paper analyses the enhancement of the energetic performance of the system. An experimental set-up is also described. The performance of the new system is described, and the limits of its realization is commented on the base of experimental recordings of the evolution of the pressure in the chambers.

Fluid Particles Straightly Forward and Circularly Forward Movements in the Direction of Tangent at Trailing Edge of Impeller Outlet in Centrifugal Turbomachinery

2003 ◽  
Author(s):  
Takaharu Tanaka
Keyword(s):  
Centrifugal Force ◽  
Flow Rate ◽  
Rotational Motion ◽  
Mechanical Energy ◽  
Centripetal Force ◽  
Impeller Outlet ◽  
Water Turbine ◽  
Fluid Particles ◽  
Centripetal Forces ◽  
Acting Force

Flow rate, which is caused in the direction radial outward in pump and radial inward in water turbine, is caused by the fluid particles straightly forward tangential movement in the direction of acting force perpendicular to impeller blades rotational radius. Impeller blades rotational motion is caused under the radial balance of centrifugal and centripetal forces. Centrifugal force is caused by the transferred energy from mechanical to hydraulic energy in pump and from hydraulic to mechanical energy in water turbine. Centripetal force is equivalent to discharge head in pump and equivalent to suction head in water turbine.

Optimal Design of Mechanical Transmissions for High Performance Servo-Drive Systems

2012 ◽  
Author(s):  
Hani A. Arafa ◽  
Mohamed L. Shaltout
Keyword(s):  
Gear Wheel ◽  
Moment Of Inertia ◽  
Reduction Ratio ◽  
Ball Screw ◽  
Mechanical Transmission ◽  
Servo Drive ◽  
Mass Moment ◽  
Mass Moment Of Inertia ◽  
Drive Systems ◽  
Servo Drive System

Optimizing the design of the mechanical transmission elements in a servo-drive system has a profound effect on its dynamic performance; the acceleration capability. Servo-drive systems can be classified, according to the type of its inertial load, into rotary and translatory systems. Accordingly, the components of the transmission system mainly include a gear set and/or a ball-screw. In this paper the effect of the mechanical transmission characteristics (moments of inertia, gear set reduction ratio and ball-screw pitch) on the acceleration capability of the servo-drive system is investigated. Three gear schemes are presented in order to describe the variation of the gear set moment of inertia as function of its reduction ratio. In the first gear scheme, the driving pinion dimensions and moment of inertia remain constant, while the driven gear wheel pitch circle diameter increases as the gear set reduction ratio increases. The second gear scheme assumes a fixed center distance between the pinion and gear wheel for any gear set reduction ratio. Finally, the third gear scheme expresses the mass moment of inertia of the pinion and the gear wheel as a function of the gear set reduction ratio and the mass moment of inertia of the pinion at unity gear ratio. A generalized relation, applicable to any gear scheme, between the pinion moment of inertia at unity reduction ratio and the applied torque is presented. The effect of the choice of the gear scheme on the acceleration capability of the rotary and translatory servo-drive systems is investigated and compared. The paper provides the servo-system designer with means for integrating the “variable” reduction gear characteristics into the mechanical model in an adaptive manner.

scholarly journals Mechanistic Analysis of Light-Driven Overcrowded Alkene-Based Molecular Motors by Multiscale Molecular Simulations

2020 ◽  
Author(s):  
Mudong Feng ◽  
Michael K. Gilson
Keyword(s):  
Molecular Motors ◽  
Performance Metrics ◽  
Multiple Scales ◽  
Mechanical Energy ◽  
Md Simulations ◽  
Maximal Power Output ◽  
Conformational Substates ◽  
Rotation Rates ◽  
Full Rotation ◽  
Energy Surfaces

We analyze light-driven overcrowded alkene-based molecular motors, an intriguing class of small molecules that have the potential to generate MHz-scale rotation rates. The full rotation process is simulated at multiple scales by combining quantum surface-hopping molecular dynamics (MD) simulations for the photoisomerization step with classical MD simulations for the thermal helix inversion step. A Markov state analysis resolves conformational substates, their interconversion kinetics, and their roles in the motor’s rotation process. Furthermore, motor performance metrics, including rotation rate and maximal power output, are computed to validate computations against experimental measurements and to inform future designs. Lastly, we find that to correctly model these motors, the force field must be optimized by fitting selected parameters to reference quantum mechanical energy surfaces. Overall, our simulations yield encouraging agreement with experimental observables such as rotation rates, and provide mechanistic insights that may help future designs.

scholarly journals Digital rotation meter

2021 ◽  
Vol 1 (2) ◽  
pp. 21-26
Author(s):  
V.V. Gerashchenko ◽  
◽  
V.P. Lobakh ◽  
N.A. Kovalenko ◽  
O.V. Bilyk ◽  
...  
Keyword(s):  
Low Cost ◽  
Gear Wheel ◽  
Rotation Frequency ◽  
Magnetic Core ◽  
The Self ◽  
Measuring Device ◽  
Light Emitting ◽  
Sensor Signals ◽  
To Receive ◽  
Splined Shaft

There was developed a digital universal measuring device for the rotation frequency of various parts: a gear wheel, a splined shaft, a special disc with slots, etc. The use of a 16-digit summing electronic counter makes it possible to form a digital code up to 65536 pulses per second, which makes it possible to install it on almost any vehicle. At the same time, it has simplicity, low cost, reliability and accuracy. The design of the meter includes a signal transducer, a self-oscillating multivibrator, logic ele-ments, and an electronic summing pulse counter. The sensor of the meter is made in the form of an inductance coil with a magnetic core. The first differentiating circuit with a diode is used as a con-verter of the sensor signals, connected to a logic AND gate, which is connected by its output through a resistor to the counting input of the counter. The input of the second differentiating circuit and the second input of the logical element AND are connected in parallel with the output of the self-oscillating multivibrator, and the input for setting the zero of the counter is connected in parallel with the output of the second differentiating circuit. The self-oscillating multivibrator is symmetrical, and the resistance of its resistors and capacitors are selected in such a way that the formation of rectangular voltage pulses and pauses duration of 1 second at its output is ensured. The presence of a sixteen-bit summing electronic counter, consisting of 16 triggers and having 16 outputs and 16 light-emitting diodes, each of which is connected to one of the outputs of the counter, allows, when the meter is turned on, to receive digital codes at their output in one second, showing the speed. An example of calculating the elements of the differentiating circuit of a multivibrator is given. The experiments have confirmed the efficiency of the developed rotational speed meter.

scholarly journals Mechanistic Analysis of Light-Driven Overcrowded Alkene-Based Molecular Motors by Multiscale Molecular Simulations

2020 ◽  
Author(s):  
Mudong Feng ◽  
Michael K. Gilson
Keyword(s):  
Molecular Motors ◽  
Performance Metrics ◽  
Multiple Scales ◽  
Mechanical Energy ◽  
Md Simulations ◽  
Maximal Power Output ◽  
Conformational Substates ◽  
Rotation Rates ◽  
Full Rotation ◽  
Energy Surfaces

We analyze light-driven overcrowded alkene-based molecular motors, an intriguing class of small molecules that have the potential to generate MHz-scale rotation rates. The full rotation process is simulated at multiple scales by combining quantum surface-hopping molecular dynamics (MD) simulations for the photoisomerization step with classical MD simulations for the thermal helix inversion step. A Markov state analysis resolves conformational substates, their interconversion kinetics, and their roles in the motor’s rotation process. Furthermore, motor performance metrics, including rotation rate and maximal power output, are computed to validate computations against experimental measurements and to inform future designs. Lastly, we find that to correctly model these motors, the force field must be optimized by fitting selected parameters to reference quantum mechanical energy surfaces. Overall, our simulations yield encouraging agreement with experimental observables such as rotation rates, and provide mechanistic insights that may help future designs.

ELECTRICAL PLATFORM FOR DRIVE OF AC ASYNCHRONOUS MOTORS AND SERVOMOTORS USING FREQUENCY CONVERTERS

2021 ◽  
Vol 21 (3) ◽  
pp. 845-856
Author(s):  
MIHAIL-FLORIN STAN ◽  
NICOLAE FIDEL ◽  
NICOLAE VASILE
Keyword(s):  
Electric Drive ◽  
Mechanical Energy ◽  
Industrial Area ◽  
Practical Implementation ◽  
Frequency Converters ◽  
Technological Production ◽  
Asynchronous Motors ◽  
Study Support ◽  
Drive Systems ◽  
The University

The development of industrial automation has implicitly led to the improvement of electric drive systems, especially since such installations are the most common form of conversion of electricity into mechanical energy. The electric drive can be defined and studied only if we consider the whole assembly of which it is part, such as the automation of a technological production process. This paper describes the design and practical implementation of a laboratory stand with a teaching feature. The designed stand is a study support for various applications used in the industrial area, offering the possibility of experimentation on programming and parameterization of frequency converters in the laboratory of "Electrical machines and drives" of the Faculty of Electrical Engineering, Electronics and Information Technology at the University of Valahia from Targoviste.

An Incentive Mechanism Using Game Theory for Wireless Mesh Networks

2013 ◽  
Vol 284-287 ◽  
pp. 2694-2698
Author(s):  
Wei Kuang Lai ◽  
Mu Lung Weng ◽  
Yuh Chung Lin ◽  
Chin Shiuh Shieh
Keyword(s):  
Game Theory ◽  
Wireless Mesh Networks ◽  
Mathematical Analysis ◽  
Mesh Networks ◽  
Pricing Model ◽  
Bandwidth Sharing ◽  
Selfish Behavior ◽  
Wireless Mesh ◽  
To Receive ◽  
Margin Area

Wireless mesh networks (WMNs) have attracted much attention in recent years. The main problems in WMNs are the unfairness in bandwidth sharing and potential selfish behavior. In this paper, an incentive-based pricing model is designed which follows the concepts of mechanism design in game theory to encourage nodes to relay packets for other nodes and therefore achieve fairness. In the pricing model, we consider the packet transmitting amounts, idle conditions and the special need of border nodes in the margin area. The incentive is the main feature of the model. We also discuss the model using mathematical analysis from various perspectives. The analysis shows that this model is highly effective in eliminating unfairness in the multi-hop transmission topology. This is achieved by allowing border mesh routers to receive a fair profit. This flexible pricing model is capable of encouraging packet forwarding. With the issue of unfairness resolved, WMNs can be expected to have a broader range of applications.

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