Search results for "Linear motion"
showing 10 items of 12 documents
Guidelines to Select Between Self-Contained Electro-Hydraulic and Electro-Mechanical Cylinder
2020
This research paper presents guidelines on how to select between self-contained electro-hydraulic and electromechanical cylinders. An example based on the motion control of a single-boom crane is studied. The sizing process of the different off-the-shelf components is analyzed in terms of design impact when replacing a traditional valve-controlled hydraulic cylinder. The self-contained electro-hydraulic solution is the best choice when a risk for high impact forces is present, when the required output power level lies continuously above 2 kW, or when installation space, weight, and cost are critical design objectives. However, the electro-mechanical solution is expected to show more control…
A stepper motor-driven microelectrode positioner
1987
The mechanical elements and the electronic control system from a stepper motor-driven microelectrode positioner is described. The unit embodies a high-precision small step angle hybrid motor. The compact, rugged and totally concentric design of the mechanic, by a spindle mechanism achieves the necessary precision by translating the stepwise rotations of the motor into steps of linear movement. The system takes advantage of commercially available low friction parts such as ball bearings, ball bushings and axles with hardened surfaces. The related electronic control unit is designed around the most recent integrated circuitry which is both sophisticated and economical. Though the described sy…
An Innovative Wave Energy Converter in the Mediterranean Sea
2018
The paper proposes a revolutionary device for the utilization of a new entry of renewable energy sources: sea wave. This technology is based on linear generators, able to converts directly a linear motion into electrical output, limiting to minimum the chain of energy conversion. A preliminary feasibility study considers a case study, applied in Lampedusa, a small island in the Mediterranean Sea. Economic and environmental assessments are reported.
Designing an innovative system for sea wave utilization
2018
For the sea wave energy exploitation, the department of Energy of Palermo University is investigating a new approach based on the mechanical motion conversion from a linear motion into a unidirectional rotary motion. This mechanical output can be used to run alternators, producing electrical power with a very simplified energy conversion chain. First preliminary tests have been realized in laboratory using a small-scale prototype.
An innovative mechanical converter for sea wave application
2017
This paper describes an innovative mechanical converter, usable in sea wave energy sector. This system transforms a variable bidirectional linear motion into a unidirectional rotary motion.
Numerical simulation of a wawe generator: A case of study
2013
The aim of present work is the numerical simulation of a linear generator, capable of directly converting the kinetic energy, available by the wave, into electrical energy, through the device linear motion (up and down). In this paper, we intend to propose a numerical simulation approach to immersed devices by applying the Immersed Boundary Method. The Theory of linear wave is used to study and reproduce sea conditions and the computational domain is created based on observations available for the site in which it is envisaged the positioning of the device.
[Velocity perception for curved motion].
1996
This study examined the effect of direction change of tangential velocity on speed perception using a dot in curved motion. The PSE values were measured for four standard stimuli of different motion curvature. In Experiment 1, semicircular motion was a comparison stimulus. The result showed that the PSE values increased with increasing motion curvature. This implies that direction change of tangential velocity can affect its speed perception. However, in Experiment 2, the effect of direction change of tangential velocity was not clear when a comparison stimulus was replaced with linear motion. In Experiment 3, the motion curvature as a comparison stimulus was set near the threshold level of…
An innovative mechanical motion converter for sea wave applications
2018
The paper shows an innovative system designed and developed by University of Palermo. The device is based on a simple mechanical converter able to transform a variable bidirectional linear motion into a unidirectional rotary motion. This technology can be successful used in sea wave applications, producing a mechanical output usable for the electrical energy production.
Wave Energy Assessment and Performance evaluation in Mediterranean Sea
2020
The paper proposes a revolutionary device for the utilization of a new entry of renewable energy sources: sea wave. This technology is based on linear generators, able to converts directly a linear motion into electrical output, limiting to minimum the chain of energy conversion. A preliminary feasibility assessment considers a case study applied in Lampedusa, a small island in the Mediterranean Sea. Economic and environmental evaluations are here reported.
Study on Improving the Functional Performance of Linear Motion Systems
2015
In the construction of high performance mechanical transmission with high precision in movement and positioning are used ball screws with preloaded double nuts. Among the factors that influence the performance of these transmissions are friction idle torque and friction load torque. Because, theoretically, the friction idle torque is influenced only by the preload force that loading, the double nut of the ball screw, was experimentally determined dependence of that torque of screw speed. Given the set was determined and exposed in the present work, the relation of dependency, idle friction torque, preload force and screw speed. From the relationship thus obtained can determine the instantan…