Angular displacement

About: Angular displacement is a research topic. Over the lifetime, 5102 publications have been published within this topic receiving 46081 citations. The topic is also known as: rotational displacement.

Scanning Mirror Control

Abstract: A scanning beam projection system (100) includes a scanning mirror (116) having a fast-scan axis and a slow-scan axis. Movement on the slow-scan axis is controlled by a slow-scan scanning mirror control system (130). The control system receives position information describing angular displacement of the mirror. An outer loop of the control system operates in the frequency domain and determines harmonic drive coefficients for a scanning mirror drive signal. An inner loop of the control system operates in the time domain and compensates for a scanning mirror resonant vibration mode at a frequency within the frequency band occupied by the harmonic drive coefficients.

Response spectra for torsion, rocking and rigid foundations

Abstract: Simple procedures are proposed for computing response spectra for torsional and rocking input ground motions assuming horizontally travelling waves of constant shape. It is shown that harmonic relationships exist between the rotational spectra and the corresponding translational spectra, and that SV rather than PSV is the correct basis for deriving the angular displacement, velocity and acceleration response spectra. An approximation enabling the use of the standard tripartite logarithmic response spectra is discussed. Simple expressions for ‘accidental’ eccentricity and rocking input effects are presented. Also proposed are multipliers to spectral ordinates to account for the filtering effects of rigid base mats resting on Winkler type foundations. For wave transit times shorter than half the natural period of the structure, these multipliers can be approximated by the frequency dependent averaging coefficients given in the literature, which are dependent, however, on the response, rather than the input, frequency.

Tool and method for measuring deflection angle of airplane control surface

Abstract: The invention discloses a tool and a method for measuring the deflection angle of an airplane control surface. The measuring tool comprises a control surface clip (1), a stabilizer clip (6), a brace rod (5), a regulating arm (4), a sensor support (3), an angular displacement sensor (7) and a forked rocker arm (2). The measuring process comprises the following steps: clamping the stabilizer clip (6) of the measuring tool to a force-bearing position of a vertical tail stabilizer (45), sequentially mounting the brace rod (5), the regulating arm (4), the sensor support (3), the angular displacement sensor (7) and the forked rocker arm (2) in place, clamping the control surface clip (1) to a force-bearing position of an upper rudder (46), and moving the angular displacement sensor (7) to a rotary shaft of the upper rudder (46) so as to measure the deflection angle of the control surface. The invention can be simultaneously used for measuring the deflection angle of the rudder or the elevator in the bench test or the ground built-in test of an airplane, can be directly used for measuring the deflection angle of the control surface without disassembling structural parts of the airframe, and is especially suitable for the condition that the deflection amount can not be educed for measurement by means of a link mechanism in case that the rotary shaft is arranged inside the envelope of the control surface.

A New Modeling of the Macpherson Suspension System and its Optimal Pole-Placement Control

Abstract: In this paper a new model and an optimal pole-placement control for the Macpherson suspension system are investigated. The focus in this new modeling is the rotational motion of the unsprung mass. The two generalized coordinates selected in this new model are the vertical displacement of the sprung mass and the angular displacement of the control arm. The vertical acceleration of the sprung mass is measured, while the angular displacement of the control arm is estimated. It is shown that the conventional model is a special case of this new model since the transfer function of this new model coincides with that of the conventional one if the lower support point of the damper is located at the mass center of the unsprung mass. It is also shown that the resonance frequencies of this new model agree better with the experimental results. Therefore, this new model is more general in the sense that it provides an extra degree of freedom in determining a plant model for control system design. An optimal pole-placement control which combines the LQ control and the pole-placement technique is investigated using this new model. The control law derived for an active suspension system is applied to the system with a semi-active damper, and the performance degradation with a semi-active actuator is evaluated. Simulations are provided.