Showing papers on "Angular displacement published in 1988"

Articulating head for a coordinate-measuring instrument

Abstract: The invention contemplates an articulating head having bearings of reproducible travel behavior, for precision angular displacment of a mounted probe-pin, about each of two orthogonal component axes of rotation. The precision of angular displacement relies upon high-resolution angle encoders for reading the instantaneous angle for each of these component axes of rotation and for reporting the same to the computer of a coordinate-measuring machine. Active position-control circuits use the angle encoders for controlling drive about the respective component axes of rotation, all in conjunction with a given program of measurements by the coordinate-measuring machine. A probe holder mounted to the articulating head can be oriented to any desired angular aspect with respect to the workpiece feature to be measured or scanned, and measurements can be made solely by controleld actuation via one or both drives on the respective axes of the articulating head, i.e., while rectilineal drives of the coordinate-measuring machine are arrested. Alignment and travel behavior of the articulation axes are determined by a calibration program and are used for correction of measurement values read from the angle-encoders of the articulating head.

Proprioception in the neck

Abstract: Proprioception in the neck was investigated in normal human subjects. Three experiments studied rotation of the head about a vertical axis on the body. Accuracy of pointing, thresholds for detection of passive movement, and control of fine movement were tested. Comparison of the accuracy of pointing at the big toe with the nose and with the arm, showed a smaller scatter of angular misalignments when pointing with the arm. However, the arm pointed systematically off target. Pointing at the target toe by turning the head was not significantly more accurate than aligning the nose and toe by turning the chair and body with the head fixed. The highest threshold found for the detection of the direction of passive movement of the head relative to the body was 1.4° angular displacement. Thresholds were highest at the slowest angular velocity and dropped as angular velocity increased. When the head was turned on the body thresholds were lower than when the body was turned and the head held still. Control of fine angular movements of the head and of the distal phalanx of the right thumb were compared by measuring subjects' accuracy in guiding a cursor through a path on a computer screen by turning the head or moving the thumb. The thumb was found to be better controlled than the head.

Apparent rotation in three-dimensional space: effects of temporal, spatial, and structural factors.

Abstract: Several experiments were performed in an effort to determine the different combinations of display parameters that can reliably elicit a perceptually compelling impression of a solid object rotating rigidly in three-dimensional space. All of the displays were computer-generated simulations of rigid objects rotating in depth under parallel projection. The parameters investigated included the number of frames in the apparent motion sequence, the temporal and spatial displacements between frames, the number of elements in the depicted object, and the structural organization of those elements. The results indicated that there are large interactions among these different parameters in their effects on the perception of structure from motion.

Motion perceptions induced by off-vertical axis rotation (OVAR) at small angles of tilt.

Abstract: Off-vertical axis rotation in darkness induces a perception of body motion which lasts as long as rotation continues. Perceived body motion is the combination of two simultaneous displacements. The most easily perceived is a translation without rotation along a conical path, at the frequency of the actual rotation. Meanwhile, the subjects feel as if they were always facing towards the same direction. The summit of the cone is generally below the head, from the waist to below the feet, and subjects have a sense of progression in the direction opposite to actual spinning. Some subjects feel, on the contrary, the summit of the cone above their heads, and the progression in the direction of spinning. Subjects also perceived another body motion, although it was faint for some of them. It consists of a rotation at low velocity in the same direction as progression along the cone. The axis of the cone is perceived as slowly rotating along a larger cone. These motion perceptions increase with tilt angle and rotation velocity. They probably result from the analysis by the Central Nervous System of the acceleration acting on the otoliths. The perceived trajectory would be reconstructed from estimates of gravity, and kinematic variables such as head translational acceleration and velocity, and head rotational velocity. The same variables would account for OVAR-induced nystagmus. Motion sickness would result from the impossibility of reconstructing a consistent body movement from most sets of values of these variables.

Least squares method and apparatus for determining track eccentricity of a disk

Abstract: A transducer head (12), held in a fixed position as a preformatted disk (16) is rotated a full revolution, reads any sector address (30) accessible to the head. The addresses read come from a plurality of track revolutions (19) that depend on the magnitude of the eccentricity of the disk. A computer (52), programmed with a least squares algorithm, first coordinates (1) data corresponding to the angular position of the disk each time an address is read, with (2) data corresponding to the actual radius of each address. The computer then transforms the array of data coordinated into a sinusoidal track eccentricity compensating signal of the form D cos (wt + E) where the amplitude D is a constant computed from the least squares algorithm corresponding to the distance between the center of the disk and its rotational axis, the phase E, which is also a constant computed by least squares, corresponds to the angle the center of the disk is from an angular reference position, and wt is a variable equal to the product of disk angular speed and time.

Process and analysis and simulation of the displacements of a horse

Abstract: Process of analysis of the complex displacements of a moving horse, consisting in: (a) placing on the horse (the saddle, for example) in real movement, measuring means (accelerometers, gyrometers, inertial control unit) by means of which one measures the speeds of linear displacement along the three axes, X, Y, Z and possibly of rotational displacement along these same axes; (b) establishing from these measurements the figurative curves, by repetitive pkeriods, of the variations of speed and position for the linear displacements and possibly for the rotational displacements; (c) analyzing these curves so as to determine its performances and its aptitudes for the different gaits, figures and jump, according to the different usages desired.

Magnetic head and disc tester employing pivot arm on linearly movable slide

Abstract: A magnetic head and disc tester imitates motions of the head on a hard disc drive and comprises a stationary base (22), a slide mechanism (24) which can be installed in any required position on the base (22) with respect to a center of rotation of a magnetic disc (D). The disc (D) is rotatingly supported by a spindle unit (42) fixed to the stationary base (22). A magnetic head (52) to be tested is attached to the end of an arm (16) which is pivotally supported on a slide (36) of the slide mechanism. The angular position of the longitudinal axis of the magnetic disc with respect to a tangent to a given track of magnetic disc (52) , i.e., a skew angle, can be adjusted and the head can be fixed in the adjusted position. For measuring the parameters of the head or the disc, the slide (36) is moved linearly and carries the magnetic head over the disc in a linear direction, the head being installed at a required skew angle by means of the above-mentioned angular adjustment. Thus, instead of rotary motion of the head with respect to the disc tracks, it is moved linearly, but maintains the same skew angle as on the disc drive. Although this approximation produces some tracking error, it is negligible, and the tester has a simpler construction and universal applicability.

Principles of measurement and instrumentation

Abstract: Instrument classification and characteristics measurement system errors instrument calibration signal processing, manipulation and transmission bridge circuits measurement of electrical signals data recording and presentation fibre optic sensors and transmission systems intelligent instruments instrumentation/computer networks temperature pressure flow level dimension measurement translational displacement transducers translational velocity acceleration, vibration and shock measurement rotational displacement transducers rotational velocity mass, force and torque measurement measurement of miscellaneous quantities.

Method for positioning a tool of a multi-joint robot

Abstract: A method for positioning a tool of a multi-joint robot is disclosed in which an incorrect positioning of the tool resulting from nonideal geometrical relationships is compensated by the following steps: determining a preliminary desired angular position for each of the joints for a desired position in space of the tool based upon the reference distances and joint axis directions required to position the tool in the desired position; determining the positioning error of the tool due to the differences between the reference distances and the desired directions and the actual spacings and actual directions of the joints; transforming the determined positioning error into corresponding angular correction values for the preliminary desired angular positions of the joints by means of an inverse Jacobi matrix coordinate-transformation equation system; calculating the error-corrected angular position for each of the joints by addition of the angular correction values to the preliminary desired angular positions; and moving the tool to the desired position by rotating the joints in accordance with the error-corrected angular position calculated.

Automotive air conditioning system

Abstract: A damper position control device for an automotive air conditioning system having a lock release mechanism for the drive shaft of a motor which controls the angular position of an air mix damper. A damper position control device is disclosed which controls the angular position of an air mix damper. The damper position control device includes a motor actuator which drives the air mix damper and a control circuit. The motor actuator includes a drive motor for the air mix damper and a rotation control device including a regulator which regulates the upper and lower rotational limits of the shaft of the drive motor and a position detector which detects the rotational angle of the shaft. The control circuit controls the motor actuator in accordance with a plurality of detected signals. The control circuit generates a drive signal which drives the motor actuator and further includes a lock detector which detects if the shaft of the motor is locked against rotational motion in a first rotational direction. The control circuit also includes a lock release which releases the motor so as to permit rotational motion in a second rotational direction after the motor as been locked against rotational motion in the first rotational direction if the motor is within a first predetermined angular displacement from the upper rotational limit or within a second predetermined angular displacement from a lower rotational limit and if the drive signal causes the motor to rotate in the second rotational direction.

Optical shaft angular and torsional displacement and speed sensing system

Abstract: A displacement detector provides a light beam which impinges on an article with different combinations of light altering materials such as reflecting and non-reflecting surfaces, wave retarding plates, and linear polarizers attached to the article to determine angular position, relative angular displacement, and speed of rotatably mounted articles. These beam altering materials change either the polarization state or the magnitude of the light in a predictable manner. When used on different ends of a rotating shaft, the shaft speed and torsional displacement of the front shaft end with respect to the rear shaft end can be determined. When used with an article such as a rotatably mounted throttle, the angular displacement of the throttle can be determined.

Two-axis mirror stabilization assembly

Abstract: To stabilize the line-of-sight of an optical image relative to a commanded line-of-sight, a stabilization system consisting of a mirror having two limited degrees of freedom, a two axis gyroscope having its two sensitive axes perpendicular to the LOS, a pickoff sensor feeding back mirror angular position, servo compensators that provide mirror torque commands to a two axis mirror torquer, and the electronic hardware that ties these components together is used

Range-finding binocular

Abstract: A range-finding binocular is disclosed which has substantially the external appearance and size of a conventional binocular. In each barrel, a system is provided for obtaining a projected image of a range-mark of circular symmetry which is focused in the focal plane of each eye lens at an accurately placed position near the visual axis of the monocular. The distance between the projected image and the visual axis is carefully controlled in order to provide, in stereovision, a sense of distance to the range-mark image which can be "placed alongside" a target of interest by changing the offset distance in a controlled manner. In one embodiment, the image is obtained by a backlighted reticle whose image passes between a transparent glass range-mark translation plate and a transparent glass adjustment plate, through a lens, and to a gold surfaced mirror for directing the projected image into the conventional path of the field of view. The range plate is carried by a holder which is hinged at one end and is pivotable through a small angle by slight fore and aft movement of the free end opposite the hinge as by a fine screw driven by a motor through a gear reduction system. Thus, the position of the range plate determines the offset of the projected image from the optical axis in each monocular, and the cumulative angular position of the motor can be interrogated to obtain and display the apparent range of the image.

Electronic angular measurement device

Abstract: The invention relates to an angular measurement device comprising a variable reluctance magnetic circuit comprising a fixed portion (3) associated with a coil (2) and at least a moving element (4) attached to a part (5) rotating in front of the fixed portion, the angular position of which is to be detected, comprising: means (I) for integrating the voltage across the coil, means for measuring the instantaneous value of the integrated voltage (15), means for comparing this measure to a calibrating curve of the integrated voltage versus the angle.

Device for sensing the angular position of a shaft

Abstract: Device for sensing angular position of a shaft utilizes a flat on the shaft, a permanent magnet with its polar axis perpendicular to the shaft axis, and a magneto-resistive element between the magnet and the flat. The resistance of the element varies linearly as the shaft is rotated from a first position to a second position.

Fiber-optic rotary displacement sensor with wavelength encoding.

Abstract: A fiber-optic sensor is described in which an optical retardation plate is used to encode rotary displacement information as a notched minimum in a broadband optical signal. As the waveplate is rotated, the optical beam experiences a variable linear retardation. The signal wavelength at which the retardation is exactly one-half wave exhibits a minimum intensity transmission. The wavelength of the intensity minimum is then a function of the rotation of the retardation plate. The theoretical prediction of the sensor’s performance is developed and compared to experimental results.

Power steering system incorporating electric motor

Abstract: A power steering system having an electric motor and including an input shaft fixed to a steering wheel, an output shaft coupled to the motor via a reduction gear, and a torsion bar provided between the input and output shafts, the output shaft being rotatable by the resultant of a manual torque for rotating the wheel and the torque of the motor. The system comprises a sensor for detecting the relative angular displacement between the input shaft and the output shaft, and a microcomputer having stored therein the relationship between the relative angular displacement and the motor current target value for determining the direction of rotation of the motor and a motor current target value from the output of the sensor to produce outputs. The relationship stored in the microcomputer is a nonlinear relationship wherein variations in the motor current target value with the relative angular displacement are small in the range of small relative angular displacements but are great in the range of great displacements.

Apparatus for measuring the mass-related characteristics of a body and its application to the measurement of the characteristics of a dry satellite

Abstract: A measuring apparatus for determining the mass-related characteristics of a body has a base which supports a receiving table for the body mounted so as to oscillate about an approximately vertical axis on either side of an angular equilibrium position to which the table is returned elastically. The base and the table are provided with an angular position detector and blocking elements. The base is supported by a movable structure which rests on a stand and is mounted so as to oscillate about an adjustable horizontal axis which intersects said vertical axis at an adjustable height on either side of a stable angular equilibrium position. The base and the movable structure are provided with a system for detecting angular position and with means for adjusting the height of the instantaneous horizontal axis of oscillation. The apparatus also has means for positioning and blocking the body with respect to the movable structure.

Broadsword anti-radar foil

Abstract: The limited advantage of chaff when the radar detection system to be confused has moving target indication (MTI) to screen out such 'slow moving' targets, is countered by the use of offset 45 degree angle fins at the base of the chaff foil pieces so as to present a doppler complication to the reflected radar wave. The rotational velocity of the foil could show up just as readily as a linear velocity of a target such as an aircraft. With many of this type of foil aloft, and each having somewhat different rotational velocities, the doppler system can conceivably be confused. At the same time, the rotation of these units help to increase the target area making a cluster of such units seem larger than actual in terms of the radar signature. The design geometry of the blade coupled with the angular displacement of the fins, serve to govern the rotational velocity of the unit in flight, thus presenting each reflecting surface for a slightly longer exposure than if the blade were pointed and the edges streamlined. Prototypes have proved the aerodynamic stability of the units, and the added advantage of compacted stowage in a limited space is readily observed.

Device for measuring the angular position and the linear displacement of two articles with respect to each other

Abstract: The invention relates to a device for measuring the angular position of a rotor with respect to a stator. Its subject is a device for measuring the angle of rotation of a rotor with respect to a stator, characterised in that it comprises 2n magnetic sensors, n being the number of sensor electrical tiers, arranged over a circumference in a manner which is fixed with respect to the stator, each sensor comprising a magnetic circuit 4, 5 provided with an emitter coil 6 and a detector coil 7, the said magnetic circuit having an airgap, the sensors being grouped in pairs, the sensors of the same group being angularly offset by an angle 180 DEG /m, two neighbouring groups being angularly spaced with respect to each other by an angle equal to k 360/m, where k is a coefficient depending on the phase number of the sensor, m and n being integers, the emitter coils all being connected in series and supplied by a.c. voltage with a frequency between 2 and 15 kHz, the device furthermore comprising a mobile element 8, 9 integral with the said rotor 1 and provided with m teeth constrained to progress through the airgap of the sensors, the detector coils of the same group of sensors being connected in series, the envelope of the signals at the terminals of these sets of coils representing, to within one phase shift, the image of the measurement of the angle of rotation of the said rotor. Application to rotating and linear electrical motors.

Device for the determination of a roll angle

Abstract: A device for determining the roll angle of a missile (10) launched from a tube (20), by means of a first magnetic-field sensor (11) located in or on the missile (10), is described. In known devices of this type, the sensor signal is dependent not only on the roll angle, but also on the flight direction of the missile (10). To obtain a definite angular relation between the missile and the phase of the sensor signal in any flight direction, it is proposed that the missile (10) should have a second magnetic-field sensor (12) located at a predetermined distance in the flight direction. In addition, a reference magnet (21) is provided on the tube (20), so that, when the missile flies past the reference magnet (21), the second magnetic-field sensor (12) generates a reference signal determining the instantaneous angular position of the missile (10). The roll angle can then be determined at any moment from this angular position by means of the detected speed of the projectile.

Method and apparatus for generating a digital signal indicative on an angular displacement

Abstract: An apparatus for generating phase modulator angular positional signals in digital form comprises a phase tracking loop receiving a phase modulated signal from the rotor (16) of a resolver (10) whose stator windings (12, 14) are excited in quadrature. The phase output of the resolver is proportional to the angular displacement (Φ) of the rotor. Signals (32, 44) for exciting the stator windings of the resolver are applied in phase quadrature to a phase detector (24) to develop an analog error signal (58) when combined with the rotor output signal (22). The analog phase error signal (58) provides an output indicative of the angular displacement of the rotor. The error signal is applied to a voltage controlled oscillator (64), converted (in 28) to digital form, and combined with the excitation signals in a closed loop to force the error signal to a null, whereupon the indicated digital output angle (at 26) is to coincide with the angular displacement of the rotor shaft.

Device for actuating the throttle valve of an internal-combustion engine of a motor vehicle

Abstract: A device is proposed which serves for actuating the throttle valve (30) of an internal combustion engine of a motor vehicle. The actuating device (18) comprises a reversible electric drive motor (32) whose output shaft (36) acts in combination with the throttle valve, (30) rotatable by way of a throttle valve shaft (34), the reference angular position of the throttle valve (30) being presettable by means of a drive lever. A simpler, more cost-effective construction for such an actuating device (18) is achieved in that the throttle valve (30) is rigidly coupled to a stop (80) to which a movable counter-stop (78) is assigned, which is spring loaded in the closing direction of the throttle valve (30) by a return spring (68, 70). The counter-stop (78) is coupled to the drive lever in such a way that it is moved by the drive lever against the force of the return spring (68, 70). … …

Fiber optic angular orientation sensor digital serial encoding

Abstract: A sensor provides remote angular orientation sensing. A rotational signal transmitted to a rotatable input shaft mounted in an encoder body causes the shaft to rotate. Light signals are transmitted through a digital code wheel mounted to the shaft. As the code wheel and shaft rotate, the light signals passing through the code wheel are superimposed with light pulses corresponding to incremental and directional changes of angular position of the code wheel with respect to the encoder body. The light signals are propagated through an optical fiber to a remote combination digital and analog circuit which converts them into a digital representation of the angular position of the code wheel.

Energy absorber for structure

Abstract: PURPOSE:To absorb such periodic energy as earthquake motion so effectively by setting up a hermetically sealed vessel and a resistance wing axis free of relatively rotational displacement with this resistance wing axis as the center according to the relative displacement between structures, and installing a resistance wing, making lead in this vessel into shearing deformation, in this axis CONSTITUTION:When strong periodic energy such as earthquake motion or the like acts between structures 1, 4, this relative displacement is converted into rotational displacement via linkage With this conversion, a hermetically sealed 8, where loacked lead is sealed in, and a resistance wing axis 13, piercing and extending an operating chamber of this vessel 8 and placing a resistance wing in this operating chamber, both are made into relatively rotational displacement with the resistance wing axis 13 as the center In consequence, the resistance wing shears and deforms the lead sealed in the operating chamber, and it absorbs periodic energy consumption at this time With absorption of this periodic energy, the relative displacement, namely, the earthquake motion between the structures is thus absorbable

System and method for updating in real time a reference position of an oscillating object

Abstract: An angular reference position, VNO, of an oscillating shaft movable about this angular position is sensed. From N samples and from a stored value being a known angular reference position, an adjustment value is obtained and the stored known angular reference position is corrected as a function of the adjustment value.

Method for detecting a reference angular position of a rotary body

Abstract: A method of detecting a reference angular position of a rotary body. Two detectable portions are spaced apart from each about the periphery by a predetermined angle in the rotational direction thereof. Two detection signals and produced from two detectors spaced apart from each other by the same angular distance as the detectable portions in the rotational direction of the rotary body in the vicinity of the locus of the detectable portions. It is first detected that at least one of the detectors produces a detection signal and thereafter it is determined that the rotary body takes a reference angular position when both of the detectors produce the detection signals.

Displacement controller for fine positioning device

Abstract: A controller for a fine positioning device constructed of planar structural units connected symmetrically and equipped individually with planar flexible beams arranged in an opposing relation between two rigid members and actuators for applying forces between the two rigid members includes displacement detection devices, displacement setting devices, sensor devices for determining the degree of each translational displacement and the degree of each angular displacement, and control devices for controlling the voltages to be applied to the respective actuators.

Apparatus for controlling the direction of a beam of optical radiation

Abstract: The apparatus includes first and second prisms (10, 11) each of small apex angle and mounted for rotation about a common optical axis (12) passing through the centres of the prisms. A third prism (13) is made from a material having a lower refractive index and has a smaller apex angle than either of the first and second prisms, and is located for rotation about the same optical axis (12). Drive means (21, 24, 27) are provided for rotating each prism independently about the common axis (12) and pick-off means (22, 25, 28) are operable to determine the angular position of each prism relative to a datum direction. Control means (29) control the positions of each prism and ensures that the third prism is positioned so that the angular deflection which it produces is opposite to the vector sum of the deflections produced by the first and second prisms.

Angular displacement detector

Abstract: PURPOSE:To detect accurately angular displacement of a specimen unaffectedly by effect of linear displacement, by fixing a plane mirror onto the specimen and irradiating the plane mirror with a beam of light of oblong cross-section. CONSTITUTION:A beam of light 10 with oblong cross-section from a light- flashing mechanism 13 is directed approximately perpendicularly to a thin plane mirror 9 fixed on a specimen 3. Next, a reflected beam of the mirror 9 is directed to a cylindrical mirror 21 as the No.1 incident light 24 and this reflected light is directed to a photoelectric conversion element 22 as the No.2 incident light 25. And, the conversion element 22 produces detecting signal 22a corresponding to an incident position of the No.2 incident light 25. Angular displacement of the specimen 3 is detected basing upon this detecting signal 22a. By this arrangement, angular displacement of the specimen can be detected accurately without an effect of the linear displacement.