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.

Digital capacitive angular-position sensor

Abstract: A capacitive angular position sensor capable of covering 360° is presented. It is made up of four quadrants, each of which consists of a parallel plate capacitor whose higher potential plate (HPP) has a specific shape. A grounded semi-circular plate, whose angular position is measured, moves between these capacitors. When these capacitors are supplied with sinusoidal voltages of mutually shifted phases in a bridge system, the phase of the output voltage of the bridge changes with the mechanical angle. Simulation results show that this relationship can be linearised if the shape of the HPPs is modified. A simple proto-type has been developed in which the shaping of the HPPs gives satisfactory improved results. The phase of the output voltage is measured digitally and the relationship between the angular position and the digital output is found to be linear, with a linearity error ±0.5% and a resolution of 3 arc minutes.

Device and method for controlling a satellite tracking antenna

Abstract: The invention relates to A device for controlling a satellite tracking antenna (10) comprising an azimuth drive means (MAz) configured to impart an azimuthal rotational motion to the antenna about an azimuth axis (Z), an elevation axis drive means (MEι) configured to impart a rotational motion to the antenna about an elevation axis (Y) orthogonal to the azimuth axis and a tilt axis drive means (Mτ; MT1, MT2) configured to impart a rotational motion to the antenna about a tilt axis (T), the tilt axis being connected to the elevation axis in such a way that the rotational freedom of motion of the antenna (19) about the tilt axis (T) is dependent on the elevation angle such that: at an elevation angle of 0° the rotational freedom of motion of the antenna (10) about the tilt axis (T) corresponds to the azimuthal rotational motion; at an increasing elevation angle the rotational freedom of motion about the antenna (10) successively transcends into a roll rotation; and at an elevation angle of 90° the rotational freedom of motion of the antenna about the tilt axis (T) corresponds to a roll rotation about a roll axis (X) orthogonal to said azimuth axis (Z) and to said elevation axis (Y), control means being provided for controlling the operation of the azimuth axis drive means, the elevation axis drive means, and the tilt axis drive means, said control means comprising means, preferably including a true north seeking gyro, for tracking position, orientation, direction and speed of movement of the device, wherein said control means further comprises an additional gyro (G) comprising an elevation gyro axis (GEI) arranged to sense the elevation movement and a tilt gyro axis (GT) arranged to sense the tilt movement, so as to minimize the angular velocity of the antenna pointing vector. The invention further relates to a method for controlling a satellite tracking antenna, and a vessel comprising said device.

A method of low-cost IMU calibration and alignment

Abstract: This paper presents a straightforward way to fully calibrate low-cost IMU sensor in field. In this approach, a plastic cube that is made by 3D printer is introduced as the body carrier of IMU. The accelerometer is firstly calibrated by using famous multi-position method and then followed with the correction of misalignment between sensor frame and body frame. A normal swivel chair is reformed as an easy turntable to perform smooth rotation. The gyroscope is calibrated by using angle domain method with the angular displacement reference that is estimated by using laser scan matching process. Experiment is executed and the comparison between raw readings and calibrated measurements is conducted, which verifies the validation of the proposed method.

Method of moving a rotary fixture

Abstract: An improved method of moving a rotary fixture (20) from a first angular position to a second angular position includes the steps of: providing a body (25); mounting the fixture on the body for rotational movement about an axis (x--x); mounting a pin (23) in the spindle (22) of a machine tool; moving the pin so as to engage the fixture at a location eccentric to the axis; and selectively moving the pin relative to the axis from one location to another; thereby to rotate the fixture from the first angular position to the second angular position.

Time gating angular displacement sensor

Abstract: The invention provides a time grating angular displacement sensor which belongs to displacement precise measuring devices. The sensor comprises a frame which is used for winding a coil and composed of an outer circle matrix and an inner circle matrix; and slots are formed on the inner peripheral wall of the outer circle matrix and the outer peripheral wall of the inner circle matrix at equal intervals. The sensor is characterized in that the excitation coil is wound on the matrix, and the induction coil is wound on the other matrix; the induction coil and the excitation coil carry out the relative motion; the excitation coil is connected with an excitation power supply, an excitation signal and an electric signal which is output by the induction coil are respectively connected to an amplification circuit and subjected to the phase comparison by a digital phase comparator after the shaping by a shaping circuit; and the phase difference of the two signals is represented by the number ofinterpolated clock pulses, further converted to the angular displacement value and directly or indirectly displayed as the angular displacement data after the treatment by a microprocessor and a memory. The sensor has the advantages of simple structure, low cost, high resolution, strong anti-interference ability and easy productization.