Showing papers on "Angular displacement published in 2013"

Transmission Lines Loaded With Bisymmetric Resonators and Their Application to Angular Displacement and Velocity Sensors

Abstract: This paper is focused on the analysis of coplanar waveguides (CPWs) loaded with circularly shaped electric-LC (ELC) resonators, the latter consisting of two coplanar loops connected in parallel through a common gap. Specifically, the resonator axis is aligned with the CPW axis, and a dynamic loading with ELC rotation is considered. Since the ELC resonator is bisymmetric, i.e., it exhibits two orthogonal symmetry planes, the angular orientation range is limited to 90°. It is shown that the transmission and reflection coefficients of the structure depend on the angular orientation of the ELC. In particular, the loaded CPW behaves as a transmission line-type (i.e., all-pass) structure for a certain ELC orientation (0°) since the resonator is not excited. However, by rotating the ELC, magnetic coupling to the line arises, and a notch in the transmission coefficient (with orientation dependent depth and bandwidth) appears. This feature is exploited to implement angular displacement sensors by measuring the notch depth in the transmission coefficient. To gain more insight on sensor design, the lumped element equivalent-circuit model for ELC-loaded CPWs with arbitrary ELC orientation is proposed and validated. Based on this approach, a prototype displacement sensor is designed and characterized. It is shown that by introducing additional elements (a circulator and an envelope detector), novel and high precision angular velocity sensors can also be implemented. An angular velocity sensor is thus proposed, characterized, and satisfactorily validated. The proposed solution for angular sensing is robust against environmental variations since it is based on the geometrical alignment/misalignment between the symmetry planes of the coupled elements.

Touch sensitive robotic gripper

Abstract: A displacement measuring cell may be used to measure linear and/or angular displacement. The displacement measuring cell may include movable and stationary electrodes in a conductive fluid. Electrical property measurements may be used to determine how far the movable electrode has moved relative to the stationary electrode. The displacement measuring cell may include pistons and/or flexible walls. The displacement measuring cell may be used in a touch-sensitive robotic gripper. The touch-sensitive robotic gripper may include a plurality of displacement measuring cells mechanically in series and/or parallel. The touch-sensitive robotic gripper may be include a processor and/or memory configured to identify objects based on displacement measurements and/or other measurements. The processor may determine how to manipulate the object based on its identity.

A novel absolute angular position sensor based on electromagnetism

Abstract: Based on the law of electromagnetic induction, a novel contactless absolute angular position sensor has been designed in the literature. It is mainly composed of three parts: two emitters, an annular encoder and a signal processing circuit. The emitter integrates a main coil and two groups of secondary windings, each of which comprises two series-wound coils with inverse enwinding directions. N and ( N − 1) copper sheets with regular shapes are arrayed uniformly in the outer and inner circles of the encoder which are corresponding to the two emitters respectively. The main coil stimulated by the external current can generate a magnetic field, which can be detected by two groups of secondary windings and a corresponding voltage signals will be exported. As the emitter rotated over any two neighboring copper sheets of the encoder, a period of sine and cosine signals will be outputted by two groups of secondary coils. The absolute angle position signals can be calculated based on the relationships between angles calculated by N and ( N − 1) periods of sine and cosine signals produced by the inner and the outer circles of emitters and the angles the emitter has rotated around the rotation axis. Experiment has been performed on a prototype of the angular position sensor and the results demonstrate the proposed scheme is feasible. Theoretic precision and testing error analysis of the sensor has been pursued at the end of the paper.

Small angular displacement measurement based on an autocollimator and a common-path compensation principle.

Abstract: A novel method for small angular displacement measurement based on an autocollimator and a common-path compensation principle by using single CCD detector was proposed. The principles of the angular displacement measurement and the common-path compensation were analyzed. The feasibility of measurement method was verified and the experimental results revealed that the linear correlativity between the relative displacement of the measuring beam spot and the angular displacement is 0.99996. And the measurement resolution is about 0.03 arcsec. To test the compensation's effect, a series of experiments introducing three different interferences from system and external environment were performed. The experimental results indicated that the standard deviations of the measuring beam spot's angular drift were improved by at least 25.0% to at most 80.0% in x direction while by at least 28.2% to at most 95.6% in y direction. Thus, the stability of the system and the measurement resolution were improved.

A new inertial piezoelectric rotary actuator based on changing the normal pressure

Abstract: A new inertial rotary actuator using two piezoelectric stacks as the power converter is proposed. The actuator rotates by regulating the friction force, which is controlled by the normal pressure, and driven by a square-wave or triangular-wave signal. Dynamic and simulation models of the actuator are established to evaluate the performance of the actuator in terms of distance, speed, radial run-out and positioning repeatability. A 40 mm wide and 32 mm high prototype was compared with the simulated model. The results show that the angular speed is proportional to the amplitude and frequency of the driving signal. A 10 μrad angular displacement resolution is obtained by applying a of 15 Vp–p square wave with a frequency of 10 Hz.

System and method for error correction in angular position sensors

Abstract: A system and method for controlling a rotating E-machine and for correcting a rotational position signal output by an angular position sensor operatively connected to the E-machine in conjunction with a sensor digital converter is disclosed. For each angular operating speed of interest, a set of signals as a function of position is taken such that the harmonics (or sub-harmonics) related to the position sensor may be determined and isolated from errors due to an associated digital converter. From this information, the magnitude and phase of the position sensor harmonics is determined. The effects of the sensor digital converter (or other signal processing equipment) are then determined and accounted for, allowing the control system to apply the total position error signal to the position sensor output signal to determine a corrected position sensor signal for use in controlling the E-machine.

Vibration gyro having bias correcting function

Abstract: A vibration gyro having a structure for canceling a quadrature error generated by structural asymmetricity due to production tolerance and a means for correcting a bias value when an angular velocity is zero. In order to apply a counter torque to a sense mass for canceling the quadrature error, left correction comb electrodes are fixed to a substrate adjacent to a left drive mass, and comb electrodes opposed to the correction comb electrodes are arranged on an inner portion of a frame member which constitutes the left drive mass. By applying DC voltage to the correction electrodes, electrostatic force, for canceling the leakage rotational displacement of the sense mass generated when the input angular velocity is zero, is generated.

Perpendicular gradiometric angle sensors, systems and methods

Abstract: Embodiments relate to magnetic field sensors, such as gradiometric magnetic field angle sensors with generally on-axis arrangements of sensor elements relative to a rotation axis of a magnet In one embodiment, an angle sensor is arranged on-axis with respect to the rotation axis of a magnet that generates a magnetic field that can be detected by the angle sensor and analyzed to determine an angular position of the magnet The sensor can comprise a plurality of sensor elements, such as two sensor elements, arranged on a substrate or die in a sensor package As it rotates, the magnet generates a magnetic field, such as an inhomogenous magnetic field having a component perpendicular to the rotation axis and acting on the angle sensor The plurality of sensor elements can detect this and other components, for example as a gradiometric sensor in which each element senses at least one component at its respective location, and the signals from the elements are compared to estimate or determine an angular position or degree of movement of the magnet

Biases in the perception of self-motion during whole-body acceleration and deceleration.

Abstract: Several studies have investigated whether vestibular signals can be processed to determine the magnitude of passive body motions. Many of them required subjects to report their perceived displacements offline, i.e. after being submitted to passive displacements. Here, we used a protocol that allowed us to complement these results by asking subjects to report their introspective estimation of their displacement continuously, i.e. during the ongoing body rotation. To this end, participants rotated the handle of a manipulandum around a vertical axis to indicate their perceived change of angular position in space at the same time as they were passively rotated in the dark. The rotation acceleration (Acc) and deceleration (Dec) lasted either 1.5 s (peak of 60 deg/s2, referred to as being "High") or 3 s (peak of 33 deg/s2, referred to as being "Low"). The participants were rotated either counter-clockwise or clockwise, and all combinations of acceleration and deceleration were tested (i.e., AccLow-DecLow; AccLow-DecHigh; AccHigh-DecLow; AccHigh-DecHigh). The participants' perception of body rotation was assessed by computing the gain, i.e. ratio between the amplitude of the perceived rotations (as measured by the rotating manipulandum’s handle) and the amplitude of the actual chair rotations. The gain was measured at the end of the rotations, and was also computed separately for the acceleration and deceleration phases. Three salient findings resulted from this experiment: i) the gain was much greater during body acceleration than during body deceleration, ii) the gain was greater during High compared to Low accelerations and iii) the gain measured during the deceleration was influenced by the preceding acceleration (i.e., Low or High). These different effects of the angular stimuli on the perception of body motion can be interpreted in relation to the consequences of body acceleration and deceleration on the vestibular system and on higher-order cognitive processes.

A theory of magnetic angle sensors with hall plates and without fluxguides

Abstract: Magnetic angle sensors detect the angular position of a permanent magnet attached to a rotating shaft. The magnet is polarized diametrically to the rotation axis. No soft magnetic ∞ux guides are present. The semiconductor die is placed on and orthogonal to the rotation axis. There are two kinds of systems: (i) perpendicular systems detect the fleld components perpendicular to the rotation axis, and (ii) axial systems detect the component parallel to the rotation axis. The former use magneto-resistive sensors or vertical Hall efiect devices; the latter use Hall plates. This paper focuses on axial systems, derives their conceptual limitations, and compares them with perpendicular systems. An optimized system and optimum shapes of magnets are reported. Angle errors due to assembly tolerances of magnet and sensor versus shaft are explained. It is proven that assembly tolerances of optimized axial systems give three times larger errors than perpendicular systems.

Shift control method of automatic transmission

Abstract: PURPOSE: A transmission control method of an automatic transmission is provided to more specifically control the release and coupling of friction elements using various control elements. CONSTITUTION: A throttle opening degree sensor(210) detects the opening degree variation of a throttle valve for delivering a signal of the opening degree variation to a transmission control unit(280). A vehicle speed sensor(220) detects the speed of a vehicle for delivering a signal of the vehicle speed to the transmission control unit. A turbine rotation number sensor(230) detects a current turbine rotation number from the angular displacement of a crankshaft. A fluid pressure sensor(240) detects fluid pressure applied on each friction element. A MG1 rotation number sensor(250) detects the rotation number of a first motor generator(MG1). A MG2 rotation number sensor(260) detects the rotation number of a second motor generator(MG2). A planetary gear set rotation number sensor(270) detects the rotation number of a planetary gear set. [Reference numerals] (210) Throttle opening degree sensor; (220) Vehicle speed sensor; (230) Turbine rotation number sensor; (240) Fluid pressure sensor; (250) MG1 rotation number sensor; (260) MG2 rotation number sensor; (270) Planetary gear set rotation number sensor; (280) Transmission control unit; (290) Map table; (300) Fluid pressure control unit;

A new 6-degree-of-freedom measurement method of X-Y stages based on additional information

Abstract: In some occasions, high accuracy and real-time 6-degree-of-freedom (6-DOF) displacements should be measured so that the control system can regulate the X-Y stages’ attitude in real time The accuracy and real-time property of measurement's result depend on not only the sensors itself, but also the accuracy and effort of the computational algorithm using the sensors’ measured data As the relation between sensors’ measured data and displacements is immensely complex and usually described as strong nonlinear coupling equation when 6-DOF displacements are all considered, computational accuracy and effort are difficult to be ensured simultaneously This paper designs a 6-DOF displacements’ measurement setup for X-Y stages based on nine interferometers’ additional information, and derives the corresponding computational algorithm For rotation, its range is usually very small and high accuracy computational results can be obtained using two interferometers’ differential computation; for translation, the closed form solutions without rotational displacement's computational error's transmission are derived by making full use of all additional interferometers’ information, so that the computational accuracy can be ensured In addition, the algorithm has simple form and doesn’t involve iteration and transcendental function's computation, so that it helps real-time computation This algorithm can acquire the computational accuracy of 10−15 rad and 10−13 mm for rotational and translational displacement separately, which can be seen in the simulation result for a lithography's wafer stage

Stair-climbing surveillance vehicle

Abstract: A robotic, wheeled surveillance vehicle capable of stair-climbing and traversing level surfaces. The vehicle comprises a rigid frame supporting a rotatable axle; an extension on which is mounted at least one surveillance device; a pair of spider assemblies rotatably supported adjacent opposite ends of said axle, each of said pair of spider assemblies supporting a plurality of rotatable wheels coupled to rotate in synchronicity; an inertial sensor supported on said frame in position to measure an angular position of at least one of said pair of spider assemblies relative to said frame; and an electric motor supported on said frame and operatively connected to drive said pair of spider assemblies to rotate. A power source supported on said frame is operatively connected to said electric motor; and a controller supported on said frame and operatively connected to said angular position sensor and said power source causes said electric motor to apply varying rotational torque to said pair of spider assemblies to cause said pair of spider assemblies to maintain a selected angular position of said spider assemblies relative to said frame as a function of input received from said angular position sensor.

Precision electromagnetic calibration technique for micro-Newton thrust stands.

Abstract: This paper introduces a new direct non-contact electromagnetic calibration technique for high precision measurements of micro-thrust and impulse. A ring-shaped electromagnet with an air gap is used in the calibration. The calibration force is produced by the interaction of a uniform magnetic field with a copper wire current in the air gap. This force depends linearly on this current as well as the steady angular displacement of the torsion arm of the thrust stand. The range of calibration force is very large and the calibration force is easy to generate and insensitive to the arm displacement. The calibration uncertainty for a 150-μN force is 4.17 μN. The more influential factor on the calibration uncertainty is the magnetization of the electromagnet core due to the copper wire current. In the impulse calibration, the exerted impulse is linearly dependent on the maximal angular displacement of the torsion arm. The uncertainty in the impulse calibration is determined by uncertainties in both the force calibration and the pulse time.

Oscillations of a quadratically damped pendulum

Abstract: A physical pendulum consisting of a circular disk at the end of a thin metal rod is connected to a low-friction rotary motion sensor, so that its angular position and velocity can be accurately measured. The disk can be oriented either perpendicular or parallel to the plane of swing to give significant or negligible air drag, respectively. The motion is analytically modeled in phase space. A quadratic dependence of the damping torque on the angular velocity fits the results. This laboratory experiment is suitable for undergraduate physics majors taking a first or second course in classical mechanics.

Permanent Magnet Thrust Bearing: Theoretical and Experimental Results

Abstract: This paper presents the design and analysis of permanent magnet (PM) thrust bearing made up of three ring pairs for flve degrees of freedom of the inner rings (rotor rings). The arrangement pattern of rings in PM bearing is considered in two ways: conventional structure and Halbach structure. The simplifled three dimensional (3D) mathematical models employing Coulombian approach and vector method are used to design the bearing. MATLAB codes are written to evaluate the axial force, stifiness and moments in both the structures for flve degrees of freedom, thereby the efiect of axial, radial and angular displacements of the rotor on the aforementioned characteristics is addressed. The results of the mathematical model are validated by the results of 3D Finite Element Analysis (FEA) and experiments. It is observed that, the conventional structure seems to be more sensitive to the angular displacement, as the percentage decrease in force and stifiness is more with respect to angular displacement than the Halbach structure. The efiect of angular displacement of the rotor on the performance of bearing in both the structures is crucial.

Haptic system for simulation of articulated mechanism operation and use thereof

Abstract: The invention relates to a haptic system meant to simulate the kinematic and dynamic operating conditions in the field of articulated mechanisms. According to the invention, the system comprises a crank (1) rotated by a user, a rotation sensor (2) placed on a shaft of a gearmotor (3) which detects the change of angular position of the crank (1) in time and transmits the data to a computing unit (4) which takes over the value of angular variation, calculates the speed and, depending on the simulated mechanism and the size of the crank (1), controls an electric motor as to generate a force return at the calculated value, at the same time the computing unit (4) displaying the image of the operating simulated mechanism on a display system (5), in accordance with the motion imparted to the crank (1) by the user.

Method for determining the angular position of an electronic module fixed to the inner face of the tread of a tire

Abstract: Method for determining the angular position of an electronic module fixed to the inner face of the tread of a tire fitted to a wheel of a vehicle. A sensor for measuring the radial acceleration of the wheel is integrated into the electronic module, measuring at least one measurement of the radial acceleration for determining the value of the period of revolution of the wheel, and detecting a variation of the radial acceleration representative of a position of the electronic module contacting the ground, the position of the electronic module in which the variation is detected is assigned the origin function of a frame of reference defined by the origin and a reference unit formed by an angular sector whose length is substantially shorter than the mean length of the footprint of the grounded tire, and the angular positions of the electronic module in the frame of reference are determined.

Design and Demonstration of a Test-Rig for Static Performance-Studies of Permanent Magnet Couplings

Abstract: The design and construction of an easy-to-use test-rig for permanent magnet couplings is presented. Static torque of permanent magnet couplings as a function of angular displacement is measured of permanent magnet couplings through an semi-automated test system. The test-rig is capable of measuring torque up to 240 Nm (in increments of 0.1 Nm) at a angular step of 0.0011 degrees (mechanical). Axial, radial, and angular misalignment can be imposed on the coupling in order to study abnormal and faulty operating conditions. This can also be used to assess installation tolerances. Measured data is stored in a USB thumb-drive, and no additional software or hardware is needed to operate the test-rig. Tests of the aligned static torque performance of two different cylindrical couplings are presented along with radial and axial misalignment-tests of one. The results demonstrates the diversity and usefulness of the the designed test-rig. Furthermore, the coupling-performance shows a clear influence of end-effects for axially short couplings, and are found to be very robust to small misalignment.

Near-linear drive systems for positioning reflectors

Abstract: System for positioning a reflector includes a base (112), yoke (104) and a reflector in the form of a lens mirror assembly (10). A motor (120) is mounted and remains substantially stationary with respect to rotation about a first axis while the yoke rotates about the first axis. A connecting rod (152) actuated for movement by the motor is mechanically coupled to the reflector so that movement of the connecting rod in relation to the yoke imparts rotation to the reflector about the second axis when the reflector is supported by the yoke. A mechanical drive system couples an output shaft of the motor to the connecting rod. The mechanical drive system is arranged so that it varies an angular position of the reflector at a rate which is linearly related to the rotation of the output shaft.

Kinematics Analysis: The Acute Effect of Different Stretching Methods on Dynamic Range of Motion of Lower Extremity Joints during Soccer Instep Kicking

Abstract: The purpose of this study was to examine the effects of static and dynamic stretching within a pre-exercise warm-up on angular displacement identified as dynamic range of motion (DROM) of hip, knee...

Monitoring apparatus and pivoting door

Abstract: Monitoring apparatus for monitoring a movement element pivoted between open and closed states of an opening to be closed, the apparatus having a sensor for detecting an object and for monitoring a spatial angle originating at or near the rotation axis. The sensor is fitted at or near the rotation axis and includes a transmitter and receiver for transmitting and receiving radiation within the spatial angle. The sensor emits detection signals generated by the receiver when radiation is detected. The monitoring apparatus includes an evaluation unit that evaluates the detection signals depending on the angular position of the detected radiation in the spatial angle and determines whether an object has been detected and/or the position of the detected object. The evaluation unit draws a distinction between the movement element and an object depending on the current angular position of the movement element.

Relative rotational angular displacement detection device, torque detection device, torque control device, and vehicle

Abstract: A relative rotational angular displacement detection device includes a pair of rotatable members relatively rotatable in a circumferential direction. A permanent magnet is attached to one of the rotatable members and includes magnetic poles magnetized in an axial direction of the axis of rotation and arranged to alternate in polarity in the circumferential direction. A magnetic flux inducing ring includes an annular ring body attached to the other of the rotatable members and is arranged coaxially with the axis of rotation, and a plurality of protrusions having a circumferential width smaller than a circumferential width of a magnetic pole. A magnetic detection portion is configured to detect a magnetic flux of the ring body of the magnetic flux inducing ring. The flux inducing ring is magnetized depending on a relative positions the protrusions and positions of the magnetic poles.

The Rigid-Flexible Robotic Manipulator: Nonlinear Control and State Estimation Considering a Different Mathematical Model for Estimation

Abstract: In this paper the author investigates the angular position and vibration control of a nonlinear rigid-flexible two link robotic manipulator considering fast angular maneuvers. The nonlinear control technique named State-Dependent Riccati Equa- tion (SDRE) is used here to achieve these aims. In a more realistic approach, it is considered that some states can be measured and some states cannot be measured. The states not measured are estimated in order to be used for the SDRE control. These states are all the angular velocities and the velocity of deformation of the flexible link. A SDRE-based estimator is used here. Not only different initial conditions between the system to be controlled (here named "real" system) and the estimator but also a different mathematical model is considered as the estimation model in order to verify the limitations of the proposed state estimation and control techniques. The mathematical model that emulates the real system to be controlled considers two modes expansion and the estimation model considers only one mode expansion. The results for the different approaches are compared and discussed.

MEMS-based state feedback control of multi-body hydraulic manipulator

Abstract: This paper presents closed-loop state feedback motion control of a heavy-duty hydraulic manipulator using solely micro-electro-mechanical systems (MEMS) rate gyroscopes and linear accelerometers for joint angular position, velocity and acceleration feedback. For benchmarking, incremental encoders with 2 million counts per revolution are also used to supply the joint motion state feedback. The two motion state estimation methods are compared using Cartesian path trajectory closed-loop control experiments with both position feedback-based proportional control and motion state-based feedback control. The experiments show that the proposed MEMS-based state feedback control yields comparable tracking results compared with the high accuracy encoder. Furthermore, the MEMS-based angular acceleration estimation in particular is free from typical differentiation induced noise amplification and post-filtering phase-lag.

System and method for linear and angular measurements of a moving object

Abstract: A system and method for measuring linear and angular displacement of a moving object, such as an autonomous moving object. In one embodiment, the system comprises at least one optical mouse sensor mounted adjacent to and at a predetermined distance from a surface of the autonomous moving object or a working surface. A processor on the autonomous moving object is operatively coupled to the optical mouse sensor. The optical mouse sensor outputs linear and angular displacement values to the processor during movement of the autonomous moving object to determine a direction and distance traveled by the autonomous moving object.