Showing papers on "Damping torque published in 1988"

Eccentrically loaded computerized positive/negative exercise machine

Abstract: A processor controlled eccentrically loaded exercise machine for providing a resisting or powering force which can be varied by position in order to carry out positive or negative exercise strokes. A variable torque motor provides a torque to a torque coupler. The torque coupler is coupled to the user interface device through a mechanical link. During a positive exercise stroke, the motor supplies a torque to a slipping torque coupler so as to provide an eccentrically loaded resisting force, which resists the force exerted by the user in moving the exercising device as his muscle contracts. During a negative exercise stroke, the torque coupler engages to provide a powering force, as supplied by torque motor, against the contracted muscle of the user. A position sensor and a load cell are coupled to the user interface device for providing position and force signals to the processor. The processor, by controlling the motor torque and the torque coupling of the torque coupler, is capable of providing a resisting or powering force which can be varied by position for providing various modes of exercise available to the user, including the ability to immediately switch between positive-negative or negative-positive exercise at any position within the exercise machines range of motion.

Actuator for the frictional engaging device

Abstract: An actuator for a four wheel drive transfer mechanism which is laid in a power transmission device and is controlled by an electrical signal sent from a controlling unit comprises a torque generating mechanism which converts electrical energy into a torque, and a torque-thrust conversion mechanism which converts the torque generated by the torque generating mechanism into a thrust force. The thrust force generated from the torque-thrust conversion mechanism is applied to the frictional engaging device to control torque distribution between front and rear vehicle wheels.

Accuracy problems of force and torque calculation in FE-systems

Abstract: The accuracy of force and torque calculation methods in finite-element (FE) systems for electromagnetic problems is discussed. The various sources of error are examined, and requirements of FE systems for an accurate force and torque calculation are derived. Theoretical evaluations are complemented by test and application results. >

Co-ordinated design of multimachine power system stabilisers based on damping torque concepts

Abstract: The author employs damping torque concepts associated with frequency response analysis, to consider the co-ordinated design of power system stabilisers (PSSs) in multimachine power systems. The aim of the proposed approach is to provide, through the action of the stabiliser, an electrical damping torque proportional to speed perturbations, i.e. Delta P/sub ei/(s)=D/sub i/ Delta omega /sub i/(s). The stabiliser network is designed to compensate for the phase lag and gain in the machine/system transfer function Delta P/sub ei/(s)/ Delta v/sub ri/(s). The stabiliser gain D/sub i/ is co-ordinated, in the first instance, so that the damping effect is distributed among those machines fitted with stabilisers in proportion to their ratings. The damping performance of a sample power system with PSSs installed is shown to be comparable to that for a multimachine system without PSSs in which a pure damping torque is introduced artificially in the transfer function block representing shaft dynamics.

Power tool for two step tightening of screw joints

Abstract: A power tool for two-step tightening of screw joints by a first high speed step for tightening the screw joint to a predetermined torque snug level (T 1 ) and a second low speed step for tightening the screw joint to a desired final torque level (T 2 ) The power tool (10) includes an electric motor, an output shaft (17), a mechanical power transmission coupling the motor to an output shaft (17), a power supply (11) connected to the motor, signal producing device (16) delivering a signal reflective of the output torque of the tool (10), and a comparator device (19, 23) for comparing the torque reflective signal with predetermined limit values corresponding to the torque snug level and to the desired final torque level and for delivering power shut-off initiating signals as the torque reflective signal attains these limit values The power tool (10) comprises a torque and speed responsive override clutch (30) for limiting the output torque to a safety torque level (T s ) well below the desired final torque level (T 2 ) but exceeding the snug level (T 1 ) in case of an inertia related torque overshoot during the first high speed tightening step A centrifugal weight (48, 49) operated lock element (45) unlocks the clutch (30) for overriding at speed levels exceeding a predetermined level only During the second low speed tightening step, the clutch (30) is locked against overriding and transfers torque without limitation

The generalized theory of indirect vector control for AC machines

Abstract: The instantaneous torque produced by an AC machine is controllable when vector control is applied However, the published papers on vector control deal with either induction machines or synchronous machines A generalized vector-control theory is developed, considering a generalized AC machine as a salient-pole synchronous machine having three kinds of torque, ie, the field torque, the reluctance torque, and the induction torque The theory can be extended to the AC machines producing a voluntarily combined torque among the three The experimental system consisted of applying the generalized vector control theory to a nonsalient-pole synchronous machine with damper winding It was verified experimentally that the instantaneous torque was controllable, not only in synchronous or induction-machine operation, but also in the transient state between the synchronous-machine operation and induction-machine operation, without any change of the control circuit >

Method of torque phase shift control for an electronic automatic transmission system

Abstract: A method of torque phase shift control for an electronic automatic transmission system to determine the apply rate of a fluid actuating device and adjusts the same to match the torque build-up of the apply element to the torque fall-off of the release element during shifting of the transmission.

Spatial versus time hysteresis in damping mechanisms

Abstract: A description is given of continuing investigations on the task of estimating internal damping mechanisms in flexible structures. Specifically, two models for internal damping in Euler-Bernoulli beams are considered-spatial hysteresis and time hysteresis. A theoretically sound computational algorithm for estimation is described, and experimental results are discussed. It is concluded that both models perform well in the sense that they accurately predict response for the experiments conducted. >

Active Control for Vibration Damping

Abstract: Active control laws are developed for an LSS-type structure to damp vibrations. High frequency modelling uncertainties lead to the necessity for a robust control design. The Linear Quadratic Gaussian with Loop Transfer Recovery (LQG/LTR) control design technique is a particular robust design technique selected for use in designing a damping control system. A summary of LQG/LTR is given and numerical example using a two bay truss is presented.

Multiple-articulated robot control apparatus

Abstract: A multiple-articulated robot control apparatus eliminates robot arm vibration by feedback-compensating disturbance due to interference torque when the robot arms are driven. The apparatus includes an arithmetic circuit (8) for computing mutual interference torque values for respective ones of the arms, a status observing circuit (2) for reproducing a status variable from a torque command and actual velocity of each servomotor, a conversion circuit (4) for converting an output of the status observing means into a corrective value of torque produced by disturbance acting upon the servomotor, and a correcting circuit (9) for correcting an error signal of the torque command of the servomotor by the converted corrective value and the interference torque value. Disturbance of each arm with regard to driving torque is eliminated. The apparatus is adapted to correct estimated disturbance torque.

Electronic monitoring device for a torque generator coupled to a load-constituting machine, and process for determining the torque and for testing the torque generator

Abstract: A torque generator, e.g. a vehicle motor on a test bed, which torque generator is coupled to a load-constituting machine, is subjected to natural vibrations which affect its difficult-to-measure internal moment. To test the torque generator, an electronic model of the vibratory test bed is used which requires the internal moment of the load-constituting machine and a value for the internal moment of the torque generator. This torque-generator moment MV' is sensed at a controller REG whose desired value is the measured shaft moment or the measured torque-generator speed and whose corresponding actual value is supplied by the electronic model. The model advantageously contains a static model Stat' which calculates a static shaft moment value MZ' for the steady state of the elastic vibration and a dynamic model Dyn' which supplies the simulated values of the shaft moment MW' or the speed nV'. Via a frequency identification IDF from the shaft-moment actual value MW, its natural frequency omega for balancing the dynamic model as well as a frequency-dependent dephased damping signal E can advantageously be formed. Elastic natural vibrations of the test bed can thereby be dampened, and the torque generator can be tested under realistic conditions, including elastic natural vibrations occurring in actual operation.

Torque sensor, in particular for electric steering mechanism

Abstract: A torque sensor for measuring the torque being transmitted by a torque bar comprises a pair of coaxial input elements carried on a torque bar and secured thereto, and being connected by a lost motion coupling. Each such input element has flexible spokes fixed to respective sides of an output collar. Steering torque stress applied to the torque bar in either direction effects rotation of a respective input element depending on direction of rotation. Thus, such directional rotation causes flexing of the flexible spokes between an input element and the output collar. Linear longitudinal movement of the output collar is thus caused in a direction depending on the direction of rotation of a respective input element. The direction and degree of movement of the output collar serves to vary a magnetic field to which an electrical measuring circuit is responsive for torque measurement. Two torque sensors can be connected in series with respect to the same torque bar to achieve various measurement effects.

Development of a rotating-shaft torque sensor for automotive applications

Abstract: Measurements of the torque in a rotating shaft are often required for automotive powertrain and engine control systems. Conventional shaft torque measurement techniques involve strain gauges and slip rings. While this approach is often used for prototypes and vehicles under development, it is too expensive and not rugged enough for production vehicles. The Ford Motor Company has supported work at Southampton University with the aim of producing a rugged noncontact shaft torque sensor, at a cost which will allow its use for automotive applications. The system described in the paper uses a novel capacitive torque sensor, which is attached to the rotating shaft. The capacitive sensor forms part of a rotating resonant circuit, which is excited across an airgap by means of inductive coupling. Variations in torque cause changes in the resonance frequency of the tuned circuit. The resonance frequency is detected as a change in referred impedance at the exciting coil. Considerable effort has been put into the design of the capacitive torque transducer. A number of practical problems have to be overcome, such as finding a suitable method of adhesion and optimising the capacitor geometry. A satisfactory sensor has now been produced, and work is now being concentrated on improving the passive telemetry system. The torque sensor is currently the subject of a patent application by the Ford Motor Company.

Damping assembly for a torque converter clutch

Abstract: A torque converter turbine, clutch and output shaft are interconnected by a planetary gear arrangement. The gear arrangement combines the output of the turbine and clutch, when engaged, at the torque converter output shaft. The turbine provides a reaction for the gear set so that transient torque spikes, or torsional vibrations, are effectively dampened by permitting the turbine to decrease in speed, and thereby absorb the torque spike energy. A clutch, between the turbine and output shaft, prevents the turbine from overrunning the output shaft when the torque converter clutch is disengaged. The clutch transmits torque from the turbine to the output shaft when the torque converter clutch is disengaged.

Electrical power steering apparatus

Abstract: A neutral condition discriminating circuit is connected to a steering torque detector and it discriminates whether a torque detection value of the steering torque detector is in a neutral condition or not, that is, whether it is substantially zero or not. When it is discriminated that the non-neutral condition of the torque detection value continues for a predetermined time, a motor output decreasing circuit decreases a current supplied to a motor which produces a steering assisting torque in accordance with the torque detection value. The hysteresis characteristic of the steering torque detector, which causes the non-neutral condition to occur even when the steering wheel is not steered, can be compensated for by reducing the steering assisting torque produced by the rotor.

Method for setting the vehicle-engine torque

Abstract: A method for setting the vehicle-engine torque comprises the step of: concentrating, in lower parts of operating ranges of engine speed of the engine, any of: operating ranges of engine speed of the engine, which ranges are determined by power output characteristics inherent in the engine; and the majority of operating ranges of engine torque. The method comprises the step of: selecting an acceleration torque set value at a time when acceleration conditions of a vehicle carrying the engine is detected by a detecting means, which acceleration torque set value is larger than a normal torque set value.

Variable-force clamping mechanism between torque-variation damping flywheel and torque converter

Abstract: In a damping flywheel which is associated with a fluid coupling device, the casing of the fluid coupling device is mounted in series with the damping flywheel, preferably through a resilient elment which forms part of an arrangement which allows variation to take place in the clamping torque exerted by friction means which form part of a torque limiter

An investigation into the torque behavior of a brushless DC motor drive

Abstract: The authors use a previously developed model for the brushless DC motor (BDCM) to investigate its torque behavior. When the input currents and motor flux linkages are perfect, no torque pulsations are produced in this motor. However, imperfections in the current arise due to finite commutation times, while imperfections in the flux linkage can arise due to the phase spread, finite slot numbers and manufacturing tolerances. Using an harmonic analysis, the effects of these imperfections on the production of torque in a BDCM are investigated. It is shown that torque pulsations and a reduction in the average value of torque is produced, both of which can affect the performance of torque, speed, and position servos. >

Torque transmission unit

Abstract: The invention relates to a torque transmission unit for lock-up clutches of hydrodynamic torque converters, particularly for motor vehicles, which can be accommodated within a converter input bell housing connectable to an engine and has a torsional vibration damper. To simplify the installation of a friction plate in such a transmission unit and to allow the attachment of additional friction plates for the transmission of a larger torque while leaving the dimensions of the transmission unit practically unaltered, at least one of the side discs is designed in such a way that it carries a friction plate fixed rotationally to it but capable of limited axial displacement.

Detection of instantaneous torque using the magnetostrictive effect in a practical ferromagnetic shaft

Abstract: A method is presented by which instantaneous torque can be detected from a ferromagnetic shaft using magnetic-head-type pickups. The method assumes linearity of the torque sensor. The output of the torque sensor is sampled per 2 pi /N radian, from which the corresponding zero level is subtracted, and then multiplied by a coefficient to correct sensitivity fluctuation. The coefficients for N sampling points are inversely proportional to the sensitivity at each sampling point. The coefficients are estimated from the sensitivities measured at M points (M >

Wheel suspension for a vehicle with a frequency-controlled damper

Abstract: In order to optimise a frequency-controlled damper for the wheel suspension of a vehicle, the damper is designed so that it possesses a high damping in the resonance frequency range of the vehicle body and wheel but low damping between them, and that in addition the phase angle between damping force and exciting oscillation is close to the value zero throughout the frequency range in question.

Automatic running control device for vehicle

Abstract: PURPOSE: To contrive the improvement of responsiveness of an automatic running control by obtaining output torque from a torque capacity coefficient and torque ratio by the torque converter characteristic and from an engine speed and controlling an engine by a difference from target torque. CONSTITUTION: An engine control unit 1 calculates target torque in accordance with a target speed or a target acceleration by a fixed car speed control means 8, when fixed car speed running is set, and by acceleration and deceleration control means 9, 10 when an acceleration and deceleration running control is set, and a control part 25 controls a throttle valve 31 to be opened and closed through an engine output adjusting means 26 so that actual torque of an engine 13 agrees with the target torque. Here as the actual torque, output torque of a torque converter, calculated from a torque capacity coefficient determined in accordance with an output shaft speed by a detecting part 22, torque ratio by a speed change shift detecting part 23 being based on the characteristic of the torque converter in an automatic transmission 23 and from an engine speed detected by a detecting part 21, is applied. Thus improving responsiveness of an engine control, an adequate automatic running control can be performed. COPYRIGHT: (C)1990,JPO&Japio

Hydraulic vibration damper

Abstract: Hydraulic vibration damper with a cylinder containing damping fluid, a piston rod and a piston, the cylinder and the piston rod each having an elastomer bearing for fixing. For damping certain natural frequencies of the wheel axle and/or the vehicle body, the elastomer bearings are designed as hydraulically damping rubber bearings, acting as a function of the frequency.

Method and apparatus for controlling the torque of an engine

Abstract: The torque of an internal combustion engine is controlled during acceleration by monitoring differences between engine and wheel speed in order to provide a measure of phase differences in the event of the engine torque oscillating. The difference between the engine and wheel signals is integrated and fed to an ignition angle correction circuit in order to damp out the torque oscillations which would otherwise result.

Method for determining the mean effective torque of an internal combustion engine

Abstract: The method determines the means effective torque of an internal combustion engine connected to a load device. The crankshaft angular velocity is scanned at equidistant angular crankshaft positions spaced apart in time by a whole number multiple of the torque harmonic period. Differentiation of the crankshaft angular velocity with respect to time also takes place by forming the difference between sequential angular velocities and by time measurement of the scanning period. The mean acceleration torque is formed by multiplying the determined crankshaft acceleration by the moment of inertia of the internal combustion engine and is added to the shaft torque recorded by use of a torque sensor to form the mean effective torque. The torque thus determined is not subject to the typical torque harmonics of the internal combustion engine.

Torque limiting arrangement

Abstract: A rotary to linear converter has a rotary input shaft and a linearly movable output element. A torque limiter arrests rotation of the shaft at a critical value of torque thereon. A friction device increase the torque on the shaft if a predetermined axial force on the output element is exceeded, this torque increase being sufficient to operate the limiter. The arrangement renders operation of the torque limiter directly responsive to axial force on the output element.

A position sensor based torque control method for a DC motor with reduction gears

Abstract: A control structure suitable for torque control using a geared DC servomotor discussed. The torque sensory feedback is advantageous for the fine torque generation by geared DC motors. However, it reduces the structural stiffness and in turn causes a low response in both the torque and position controls. To improve this, it is suggested that the natural frequency of the motor rotor position servosystem should be large. The suggestion is verified by experiments on a single-joint manipulator. >

Multi-stage torque converter with integrated damper

Abstract: A power transmission system includes a multi-stage torque converter and an integrated vibration damper assembly. The torque converter fluid circuit includes, in series relation, an impeller, circulatory turbine, main turbine, and reaction member or stator. The vibration damper assembly includes an input member, an output hub assembly and a resilient member interposed between. The output hub assembly is operatively connected to the transmission output. A circulator turbine output is drivingly connected to an output shaft through the vibration damper assembly, rather than through the separate circulatory turbine drive plate of a conventional torque converter. In this matter, the vibration damper assembly where a conventional damper assembly would not provide a power output path.