Showing papers on "Angular displacement published in 1989"

Angular displacement sensors

Abstract: A sensor for detecting angular displacement of an object. The sensor comprises a substrate for attachment to the object whose angular displacement is to be sensed and a sensing means attached to the substrate and connectable into an electric circuit. The electric circuit measures the resistance of the sensing means, which changes as a function of the angular displacement. Several embodiments are disclosed, including a conductive elastomer sensor, a conductive ink sensor, a sliding resistor sensor, a force sensitive resistor sensor and a conductive fluid sensor.

Measuring apparatus for pedal-crank assembly

Abstract: Apparatus measures output parameters including torque, work, power, rpm and time for selected rotations of the user of a power-using device having a pedal-crank assembly. Torque vs. angular position values are input from rotating strain gauges and angular position sensors to a programmed microprocessor which stores and processes this data. An approximate-integration algorithm produces a value for work produced over a selected rotation. This work value is further divided by the time interval to produce a value for the instantaneous power being produced. With appropriate sensors, many forms of data for both right and left crank arms can be displayed and/or stored separately.

Trajectory control of a non-linear one-link flexible arm

Abstract: The trajectory-tracking control problem is considered for a one-link flexible arm described by a non-linear model. Two meaningful system outputs are chosen; namely, the joint angle and the angular position of a suitable point along the link. The common goal is to stiffen the behaviour of the flexible link with respect to the chosen output. Based on the input-output inversion algorithm, a state-feedback control law is designed that enables exact tracking of any smooth trajectory specified for the output. In the closed loop an unobservable dynamics naturally arises, related to the variables describing the arm's distributed flexibility. Joint-based design is shown to be always stable, whereas in the link-point design the closed-loop dynamics may become unstable depending on the location of the output along the link. Open- versus closed-loop strategies are developed and compared. Extensive simulation results are included.

Polychromatic optical strain gauge

Abstract: A method and apparatus for measuring strain of an object is provided. The object to be measured is provided with a diffraction grating which is illuminated with radiation including at least two frequencies to produce an interference pattern. At least a portion of the interference pattern corresponding to at least one of the frequencies is detected and analyzed to determine strain. In some embodiments, the frequency of a portion of the diffraction pattern is detected, for example, by a human eye and the detected frequency compared with known frequencies to determine strain. In other embodiments, the relative angular position of portions of the pattern corresponding to different frequencies is detected. Since the relative angular position and intensity is affected by strain but not by certain rigid body rotations, strain measurement free of body rotation error may be made.

Manipulator and control method

Abstract: A multiple-degree-of-freedom manipulator having a plurality of joints is improved by providing some of said plurality of joints being provided with holding brakes, and providing any remaining joints with actuators which generate angular acceleration or linear acceleration in the joints provided with holding brakes while the holding brakes of the joints are released. A method of controlling the multiple-degree-of-freedom manipulators provided with one or more joints provided with holding brakes and one or more joints provided with actuators, comprises the steps of controlling the angular displacement or linear displacement of joints which have no actuators by the torque or force of joints which have actuators by means of the dynamic coupling between joints while the holding brakes are released, and controlling the angular displacement or linear displacement of joints which have actuators by means of the actuators while the brakes are engaged.

Nonstationary Vibration of a Rotating Shaft with Nonlinear Spring Characteristics During Acceleration Through a Critical Speed : A Critical Speed of a 1/2-Order Subharmonic Oscillation

Abstract: This paper deals with the nonstationary oscillations of a flexible rotating shaft with nonlinear spring characteristics. In particular, we investigate a phenomenon during constant acceleration and deceleration passing through a critical speed of a 1/2-order subharmonic oscillation of forward precession. In numerical simulations, we examined the influence of the angular acceleration λ and the initial angular position ψ0 of a rotor unbalance on the maximum amplitude of the subharmonic oscillation. As a result, the following points are clarified: (1) the maximum amplitude depends markedly on λ and ψ0; (2) in order to always pass through this critical speed with finite amplitude during acceleration, an angular acceleration greater than a certain value λ0 is necessary; and (3) when the angular acceleration is less than this critical value λ0 (0<λ<λ0), the shaft's ability to pass through this critical speed depends on ψ0. We ascertained the validity of these theoretical results by experiments.

Multi-function machine tool which permits complex machining of long pieces

Abstract: The machine tool of the invention combines the following three features: the workpiece holder (22) rotates around an axis (C) which is referred to as horizontal turning axis and is parallel to one (X) of the three orthogonal axes (X, Y, Z), the said axis (C) overlying a table (12) the flat upper-face of which is parallel to said turning axis (C) and comprises means for fastening one or more support and/or centering means (15, 24); the toolholder (38) comprises two clamping mandrels, one for a stationary tool and the other for a rotary tool; the workpiece holder is in relation with drive means (23, 25) which confer upon it one of the three kinematics of the following kinematic group: immobilization in a given angular position, a so-called slow speed of rotation for milling operations which are not parallel to the axis (C), and a so-called high speed for the turning.

Method and device for measuring the angle of rotation of the steering shaft of a motor vehicle

Abstract: The method consists in measuring the speed VV of the vehicle, in comparing the current speed VV to a predetermined speed VM in order to zero a shaft rotation counter (11) when VV is greater than VM VM is updated to the value VV when VV is greater than VM The direc­tion of movement of the shaft into a position corres­ponding to an extremum of the signal emitted by a sensor 1 sensitive to the angular position of the shaft during one turn is detected, in order to increment or decrement the counter according to the direction detected The number of turns recorded is combined with the current signal VS emitted by the sensor 1 in order to form a signal representing the angle of rotation of the steering shaft, during several turns Application to a device for controlling an adaptable suspension for a motor vehicle

Linear/Angular Displacement Interferometer For Wafer Stage Metrology

Abstract: A dual measurement interferometer has been developed specifically for wafer stage metrology. The interferometer concurrently measures both linear and angular displacement. It is designed to conserve space, minimize stage mass, eliminate heat sources and provide high resolution and slew rate.

Disk-type single-phase brushless motor

Abstract: A disk-type single-phase brushless motor wherein a reluctance torque having a sufficient magnitude can be generated to assure self-starting and continued rotation of the motor and production of disagreeable noises is minimized. The motor comprises a stator yoke mounted in an opposing relationship to a magnet rotor with an axial air gap left therebetween. The magnet rotor has an equal circumferential pole width θ. The stator yoke has a cutaway portion formed therein for enabling self-starting of the motor. The cutaway portion has a specific shape including a first radially extending edge and a second edge extending in a predetermined angular relationship from an inner end of the first edge to an outer circumferential edge of the stator yoke. The stator yoke is positioned at a predetermined angular position relative to a coreless armature coil so that the first edge thereof may be angularly spaced by a predetermined angle from a position at which a maximum starting torque is produced in the direction opposite the direction of rotation of the rotor.

Torque and angular displacement sensing in controlled wrenches

Abstract: The torque and angular displacement transducers in a controlled wrench apparatus are relocated to reduce the problems encountered therewith from the harsh physical environment experienced by such transducers in conventional designs. In one preferred embodiment, both the torque and angular displacement transducers are located at remote locations from the movable elements of the wrench mechanism and are each housed in a conventional hydraulic fitting to be more readily replaceable for maintenance purposes, as compared to the transducers of conventional designs.

Axial spline drive lug

Abstract: An axially toothed gear mechanism for transmitting torque and angular displacement from a driving member to a driven member which can accommodate a slight angular mismatch between the two, and which minimizes backlash and wear of the teeth.

Method and apparatus for providing runout compensation

Abstract: A wheel alignment system includes a gauge head which is adapted to be pendulously mounted to a wheel to be aligned for free rotation about an axis which is coaxial with the axis of rotation of the wheel. The gauge head carries a plurality of level sensors, which are coupled to a microprocessor, and an encoder which is mounted between a shaft, that is mounted to the wheel for rotation therewith, and the gauge head to transmit to said microprocessor signals representative of the angular position of said wheel.

Dual angular adjustment device for coarse and fine angular rotation of a shaft relative to a releasably connectable component

Abstract: A device for adjusting the angular position of rotation of a steering wheel hub of a motor vehicle relative of a steering shaft utilizing a bushing which is located between these parts and connected to each of these by sets of teeth distributed uniformly over the inner and outer periphery of the bushing and wherein these teeth offer a large number of possibilities of angular adjustment as a result of the engagement of one set of teeth with the steering wheel hub for a coarse adjustment and as a result of the engagement of the other set of teeth with the steering shaft for an even larger possibility of minor angular adjustment.

Laser scanner device

Abstract: A piezoelectric actuator capable of producing a linear displacement is used for the control of deflection angle of a scanning deflection mirror. To convert the linear displacement produced by the piezoelectric actuator into rotational displacement, a lever contacting the piezoelectric actuator is attached to the rotary shaft of the mirror and is urged by a spring in the direction counter to the direction of rotation caused by the piezoelectric actuator. An amplifying mechanism amplifies a small displacement produced by the piezoelectric actuator into a large rotational displacement proportional to the linear displacement produced by the piezoelectric actuator, thereby imparting a desired deflection angle to the deflection mirror. A mechanism for detecting rotational displacement is associated with the input or the output shaft of the amplifying mechanism to feedback any positional offset. When the detection mechanism is associated with the output shaft, the rotational displacement is converted again into a linear displacement through a pinion-and-rack mechanism and the amount of linear displacement of the rack is sensed by a non-contact type linear sensor as an amount which corresponds to the amount of rotational displacement.

Angular position sensor - has mirror or object deflecting light beam to annular sensor

Abstract: The angle transducer for determining the rotation position of a component wrt. a fixed arrangement contains a fixed light source (1), a mirror (4) mounted on the component (6) which reflects the light beam and a sensor mounted in the reflected light beam which detects the light beam position. The beam (7) from the source is parallel to the rotation axis (5). The mirror surface is inclined wrt. the light beam so that reflected light falls on at least one CCD based annular sensor arrangement (2) concentric wrt. the rotation axis. ADVANTAGE - Achieves high resolution angular position measurement.

Angular Induction as a Function of Contact and Target Orientation

Abstract: The Poggendorff effect is seen as misalignment of two obliques, or misprojection of one, when the obliques are placed outside a set of parallel lines. To understand better the mechanisms behind this effect, the orientation of the lines which are normally parallel was systematically manipulated. The results indicate that projection bias is affected by the orientation of either line, is at a minimum where the line is orthogonal to the oblique, and is maximal at small angles. This is in line with classic theories which attribute the illusion to misperception of angular size. However, such explanations presuppose that in order to be effective the induction line must be proximal to the oblique so that an angle can be formed. Results are reported which show that the angle formed by the oblique and a line placed at a distance from the oblique, serving as the target of the projection, follows an angular rule of effectiveness similar to what is seen when the line is placed directly in contact with the oblique. The underlying process is described as 'angular induction'.

Method and device for movement guidance of multi-axis manipulators

Abstract: Method for movement guidance of multi-axis manipulators, in particular industrial robots, proposes that the movement guidance be divided into the preselection of successive translational and rotational movements of the manipulator tool. In this case, the translational movements are generated by the alignment of a guiding device which is freely movable in space and is designed with a pistol-like housing, and their end point is generated by a time-limited speed preselection. The rotational movements are in each case obtained by a change of the spatial angular position of the guiding device. In order to determine the respective spatial orientation of the guiding device, two non-parallel fields are used, and these fields may be the final magnetic field and gravitational field.

Involute cam actuator with piston drive

Abstract: A mechanism for converting linear displacement of a piston to angular displacement of a shaft by positioning a cam in a recess of a unitary piston which is adapted for positioning by differential fluid forces applied to opposite ends of the piston. To provide a linear displacement drive for a shaft positioned to rotate about an axis perpendicular to the axis of the piston, a cam profile consisting of two symmetrical, opposite and identical involutes is employed.

Method of fabricating article having aspheric figure and tool for use in carrying out the method

Abstract: A method of and apparatus for fabricating an article having an aspheric figure, wherein the three-dimensional positional relationship between a work and a grinding spindle as a processing tool is controlled in terms of a polar coordinate system. The grinding spindle extends in a plane which is perpendicular to the direction of rotation of said work and is made to swing along an arcuate path. The distance between the axis of rotation of the work and the axis of the swing of the grinding spindle is changed in relation to the rotational angular position of the work.

Device for forming a corner on a piece of furniture

Abstract: With a device for forming a corner on a piece of furniture, in particular for receiving a standing leg and for receiving supporting profiles for a table top or the like, a solution is to be provided with which a fitting, in particular for forming tables, which can be adapted to various angular shapes is provided using comparatively simple means. This is achieved in that the device is formed from two fitting parts which are substantially mirror-invertedly identical and equipped with engaging elements for fastening the supporting profiles or other assembly elements, the fitting parts being able to be fixed to one another so as to be variable in their angular position relative to one another about an axis corresponding to the longitudinal axis of the standing leg.

Torque detecting apparatus

Abstract: The present invention relates to a torque detecting apparatus provided with a conversion device, which is positioned on the axis of one of an input shaft and an output shaft extended on a same axis and mutually connected by a torsion bar and which serves to convert the relative rotational displacement between the input and output shafts into a linear displacement, a slidable member causing a sliding motion corresponding to the linear displacement obtained by the conversion by the conversion device, and detection device for generating an electrical signal by detecting the sliding motion of the slidable member. The conversion device comprises a lever shaft portion, a leg portion and link arrangement. The leg portion oscillates, when the lever shaft portion of conversion device is rotated by the link arrangement, to cause the sliding motion of a slidable member, engaging with the leg portion on the other shaft.

Apparatus for aligning the optic axis of an intra-cavity birefringent element, and tunable laser using same

Abstract: Alignment of a birefringent tunable laser gain medium characterized by a first face and a second face cut at Brewster's angle so that a plane of polarization is defined. The gain medium is secured in the optical path by a rotatable member having an axis of rotation that is normal to the Brewster faces of the optical device. Coupled with the rotatable member is a support allowing adjustment of the angular position about the axis of rotation fo the rotatable member. An operator adjusts the angular position of the rotatable member until the C-axis of the gain medium lies in the plane of polarization. Even though the C-axis may not be parallel to the direction of polarization, the depolarization effects of the misalignment are eliminated by proper adjustment of the angular position relative to the plane of polarization. A tunable, solid state laser using the alignment apparatus with a birefringent filter achieves greater linear tuning range.

Angular displacement sensor

Abstract: A displacement sensor, particularly for monitoring angular displacement over 360°, uses two transducers (1, 2 and 1, 3; 1, 2 and 3, 14, 16; 24-26) whose moving parts (2, 3; 26) are coupled for synchronous displacement over respective paths. Each transducer has a measurable parameter. For the first transducer (1, 2; 24-26), the path has a plurality of equal portions (AB, BA) in each of which the parameter varies uniformly over the same range. For the second transducer, the values or ranges of its parameter are characteristic of the portions. Thus they can provide a logic signal for indicating the path portion so that the parameter value of the first transducer determines the displacement position uniquely. For example, the first transducer may be a rotary potentiometer (1, 2) with 180° taps (A, B). The second transducer (3, 14, 15) may employ two 180° contact plates (14, 15) held at high and low potential (respectively), and a sliding contact (3) rotationally fast with the contact (2) of the potentiometer.

System for compensated motion of coupled robot axes

Abstract: A system for accurately and smoothly moving the tool centerpoint of a manipulator device. The system includes means for measuring the angles at the elbow pivot joint and shoulder pivot joint of the manipulator device. Required compensating movement in a second axis of the manipulator linkage as a result of movement in a first axis thereof is anticipated by the control system to enable substantially simultaneous movement of both axes, and feedback of the angular position of the pivot joints during such movements enables enhancement of the precision of the tool centerpoint movement.

Method for determining a rotational angle of a rotary body

Abstract: For the purpose of knowing an angular position and a rotational speed of a rotary body, according to an encoding pattern on an encoder mounted to and synchronously rotated with the rotary body, rotational angular position signals consisting of n-phase rectangular waves and sensing pulses occurring at a predetermined rotational angle interval are generated. In response to the issue of each sensing pulse, levels of the respective rotational angular position signals are detected, a variation pattern of a combination of the detected n levels is compared with a reference variation pattern, and it is determined whether an abnormal condition has arisen or not, and if the condition is normal, whether the variation pattern is a forward traveling pattern or a backward traveling pattern. In the case of the forward traveling pattern, (+1) is added to a rotational angle counter, while in the case of the backward traveling pattern, (-1) is added to the rotational angle counter.