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A simulation table or multi-axis shaker table (MAST) is an automotive test system specifically designed for the high-frequency testing of vehicle components.
They can simulate acceleration and displacement outputs and reproduce key data collected on proving grounds by providing a full six degrees of freedom (6 DOF).
These test systems consist of a hexapod platform with a low resonance table on top. The test system can be used to simulate any kind of vibration in all six degrees of freedom.
The movements of the test system are tightly controlled by a digital test controller.
Simulation tables can be either electrical or hydraulical. Electric simulation table usually achieve a frequency range up to 25 Hz with a maximum payload of around 500 kilograms (1,100 lb).
For higher payloads or frequencies hydraulic simulation tables are used. Low frequency hydraulic simulation tables can easily reach 0.1 Hz to 120 Hz and test payloads up to 100 tons, while specialized high frequency simulation tables can reach in excess of 100 Hz, with more than 14 G of vertical acceleration to payloads beyond 680 kg (1,500 lb).
An industrial robot is a robot system used for manufacturing. Industrial robots are automated, programmable and capable of movement on three or more axes.
Vehicle dynamics is the study of vehicle motion, e.g., how a vehicle's forward movement changes in response to driver inputs, propulsion system outputs, ambient conditions, air/surface/water conditions, etc. Vehicle dynamics is a part of engineering primarily based on classical mechanics. It may be applied for motorized vehicles, bicycles and motorcycles, aircraft, and watercraft.
An accelerometer is a device that measures the proper acceleration of an object. Proper acceleration is the acceleration of the object relative to an observer who is in free fall. Proper acceleration is different from coordinate acceleration, which is acceleration with respect to a given coordinate system, which may or may not be accelerating. For example, an accelerometer at rest on the surface of the Earth will measure an acceleration due to Earth's gravity straight upwards of about g ≈ 9.81 m/s2. By contrast, an accelerometer that is in free fall will measure zero acceleration.
A Stewart platform is a type of parallel manipulator that has six prismatic actuators, commonly hydraulic jacks or electric linear actuators, attached in pairs to three positions on the platform's baseplate, crossing over to three mounting points on a top plate. All 12 connections are made via universal joints. Devices placed on the top plate can be moved in the six degrees of freedom in which it is possible for a freely-suspended body to move: three linear movements x, y, z, and the three rotations.
STS-87 was a Space Shuttle mission launched from Launch Complex 39B of the Kennedy Space Center on 19 November 1997. It was the 88th flight of the Space Shuttle and the 24th flight of Columbia. The mission goals were to conduct experiments using the United States Microgravity Payload (USMP-4), conduct two EVAs, and deploy the SPARTAN-201 experiment. This mission marked the first time an EVA was performed from Columbia. EVAs from Columbia were originally planned for STS-5 in 1982 and STS-80 in 1996, but were canceled due to spacesuit and airlock problems, respectively. It also marked the first EVA conducted by a Japanese astronaut, Takao Doi.
A variable-frequency drive is a type of AC motor drive that controls speed and torque by varying the frequency of the input electricity. Depending on its topology, it controls the associated voltage or current variation.
A motion simulator or motion platform is a mechanism that creates the feelings of being in a real motion environment. In a simulator, the movement is synchronised with a visual display of the outside world (OTW) scene. Motion platforms can provide movement in all of the six degrees of freedom (DOF) that can be experienced by an object that is free to move, such as an aircraft or spacecraft:. These are the three rotational degrees of freedom and three translational or linear degrees of freedom.
The European Space Research and Technology Centre (ESTEC) is the European Space Agency's main technology development and test centre for spacecraft and space technology. It is situated in Noordwijk, South Holland, in the western Netherlands, although several kilometers off the village but immediately linked to the most Northern district of the nearby town Katwijk.
A Shock Response Spectrum (SRS) is a graphical representation of a shock, or any other transient acceleration input, in terms of how a Single Degree Of Freedom (SDOF) system would respond to that input. The horizontal axis shows the natural frequency of a hypothetical SDOF, and the vertical axis shows the peak acceleration which this SDOF would undergo as a consequence of the shock input.
Vibration isolation is the prevention of transmission of vibration from one component of a system to others parts of the same system, as in buildings or mechanical systems. Vibration is undesirable in many domains, primarily engineered systems and habitable spaces, and methods have been developed to prevent the transfer of vibration to such systems. Vibrations propagate via mechanical waves and certain mechanical linkages conduct vibrations more efficiently than others. Passive vibration isolation makes use of materials and mechanical linkages that absorb and damp these mechanical waves. Active vibration isolation involves sensors and actuators that produce disruptive interference that cancels-out incoming vibration.
Space Power Facility (SPF) is a NASA facility used to test spaceflight hardware under simulated launch and spaceflight conditions. The SPF is part of NASA's Neil A. Armstrong Test Facility, which in turn is part of the Glenn Research Center. The Neil A. Armstrong Test Facility and the SPF are located near Sandusky, Ohio.
A vibrator is a mechanical device to generate vibrations. The vibration is often generated by an electric motor with an unbalanced mass on its driveshaft.
National Center for Research on Earthquake Engineering is an organisation in Da'an District, Taipei, Taiwan.
The 7 post shaker is a piece of test equipment used to perform technical analysis on race cars. By applying shaking forces the shaker can emulate banking loads, lateral load transfer, longitudinal weight transfer and ride height sensitive downforce to emulate specific racetracks.
There are different experimental techniques which can be used to test the response of structures and soil or rock slopes to verify their seismic performance. One of these is using an earthquake shaking table. This device is used for shaking scaled slopes, structural models or building components with a wide range of simulated ground motions, including reproductions of recorded earthquake time-histories.
Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. Vibration may be deterministic if the oscillations can be characterised precisely, or random if the oscillations can only be analysed statistically.
Pyroshock, also known as pyrotechnic shock, is the dynamic structural shock that occurs when an explosion or impact occurs on a structure. Davie and Bateman describe it as: "Pyroshock is the response of a structure to high frequency, high-magnitude stress waves that propagate throughout the structure as a result of an explosive event such as an explosive charge to separate two stages of a multistage rocket." It is of particular relevance to the defense and aerospace industries in that they utilize many vehicles and/or components that use explosive devices to accomplish mission tasks. Examples include rocket stage separation, missile payload deployment, pilot ejection, automobile airbag inflators, etc. Of significance is the survival and integrity of the equipment after the explosive device has activated so that the vehicle can accomplish its task. There are examples of flight vehicles Boeing-The Aerospace Corp which have crashed after a routine explosive device deployment, the cause of the crash being determined as be a result of a computer failure due to the explosive device. The resultant energies are often high g-force and high frequency which can cause problems for electronic components which have small items with resonant frequencies near those induced by the pyroshock.
The Triaxial Earthquake and Shock Simulator (TESS) is an experimental 3-dimensional "shake table," is used to test the ability of systems and facilities to survive under realistic conditions of weapons-induced shock and vibration, and earthquake ground motion. TESS serves in a wide variety of testing roles, including testing shock survivability of computer equipment (shown below), computer floors, and shock isolation systems in military facilities; studying the behavior of structural building models and components in seismic environments with a focus on ways to increase the seismic resistance of steel, reinforced concrete, and masonry structures; subjecting full-size electronic systems to simulated transportation and seismic environments; and determining the effects of shipboard vibrations on naval systems.
Vibration calibrators , sometimes also called reference shakers, are electromechanical instruments which enable calibration of vibration sensors and measuring instruments to traceable standards. They produce sinusoidal mechanical vibration signals with known amplitudes and frequencies. The vibrating part of the instrument is usually a cylindrical steel stud with an internal thread for attachment of the test object. An electrodynamic or piezoelectric actuator system is used to produce the vibrations. With older instruments it was necessary to adjust the vibration amplitude according to the weight of the test object. However, modern instruments contain a built-in reference accelerometer and closed-loop control, with which the amplitude is kept constant up to a maximum specified weight of test object. Older models can be used to calibrate objects weighing up to a maximum of approximately 100 g, whereas the latest instruments can work stably with test objects weighing over 500 g.
A high performance positioning system (HPPS) is a type of positioning system consisting of a piece of electromechanics equipment (e.g. an assembly of linear stages and rotary stages) that is capable of moving an object in a three-dimensional space within a work envelope. Positioning could be done point to point or along a desired path of motion. Position is typically defined in six degrees of freedom, including linear, in an x,y,z cartesian coordinate system, and angular orientation of yaw, pitch, roll. HPPS are used in many manufacturing processes to move an object (tool or part) smoothly and accurately in six degrees of freedom, along a desired path, at a desired orientation, with high acceleration, high deceleration, high velocity and low settling time. It is designed to quickly stop its motion and accurately place the moving object at its desired final position and orientation with minimal jittering.