1341 results about "Friction torque" patented technology

The present invention relates to a variable-torque magnetorheologically actuated prosthetic knee which utilizes a plurality of interspersed and alternating rotors and stators to shear magnetorheological fluid in gaps formed therebetween. Advantageously, by operating in the "shear mode" there is substantially no or negligible fluid pressure buildup or change. Moreover, the multiple MR fluid gaps or flux interfaces desirably allow for the production of a large torque at low speed-eliminating the need for a transmission-and also for a wide dynamic torque range. One embodiment of the invention allows the rotors and/or stators to close the gaps therebetween to create a frictional torque component, thereby forming a "hybrid" braking system which provides a total torque or damping which is a combination of viscous torque and frictional torque.

The invention relates to a PMSM servo system control method based on fuzzy and active disturbance rejection control. A position signal is given by a differential tracker to arrange a transition process so that the contradiction between rapidness and overshoot of a system is solved, and uncertainty, friction torques and external disturbance due to modeling errors of the system are observed via an expansion state observer; according to the error between the differentials generated by the differential tracker and state variation generated by the expansion state observer, a fuzzy inference rule is obtained with application of experimental experience of technical staff, so that a fuzzy rule control table of an error proportion coefficient, a differential coefficient and an integration coefficient is established; accurate control amount is obtained after de-fuzzification, so that parameter self-adaptive adjustment of a nonlinear error feedback control law is realized; and compensation amounts of the nonlinear error feedback control law and the expansion state observer to the total disturbance forms the control amount, thereby realizing optimal control for an controlled object. The method of the invention improves both tracking precision and disturbance rejection capability of the system.

An anti-lock braking system includes a friction torque gradient estimating unit for estimating, from a small number of parameters, the gradient of friction torque with respect to a slip speed, and controls a braking force acting on wheels on the basis of the friction torque gradient estimated by the friction torque gradient estimating unit. The friction torque gradient estimating unit may employ several types of estimating methods; e.g., a method of estimating the gradient of friction torque from only time-series data concerning a wheel speed; a method of estimating the friction torque gradient from time-series data concerning wheel deceleration as well as from braking torque or time-series data concerning physical quantities associated with the braking torque; or a method of estimating the friction torque gradient from micro-gains which are obtained when brake pressure is excited in a very small amount at the resonance frequency of a vibration system comprising a vehicle, wheels, and a road surface and which represent the characteristics of the vibration system. Further, there is also disclosed a method of determining, from the thus-estimated friction torque gradient, the limit of the characteristics of friction torque developed between the wheels and the road surface.

A control method and a control system of tension in the process of rolling periodic variable-thickness strips belong to the technical field of rolling. The method comprises the following steps: dividing segments on the rolled pieces, setting front and back tension values in each zone, realizing tension open-loop control and tension closed-loop control based on maximum torque limit and adding a dynamic torque compensation link and a mechanical friction torque compensation link; controlling torques of an uncoiler and a coiling machine motor and setting speed. The system comprises a rolling mill; coiling machines are arranged at both sides of the rolling mill respectively; length-measuring rollers are arranged between the coiling machines and the rolling mill; thickness gauges are arranged at both sides of the rolling mill respectively; coil diameter gauges are arranged on the coiling machines; a rolling force sensor and a hydraulic cylinder are arranged on the rolling mill; tensiometers are arranged below the length-measuring rollers and pulse coders are arranged on the length-measuring rollers; the thickness gauge, the coil diameter gauge, the rolling force sensor, a displacement sensor of the hydraulic cylinder, the tensiometer and the pulse coder are respectively connected with a computer control system.

A driving power control device for a hybrid vehicle controls the engagement state of a lockup clutch so that high efficiency in regeneration is obtainable. The driving power control device for a hybrid vehicle includes an engine and a motor-generator as power sources, an automatic transmission disposed between the power sources and driving wheels with an intervening torque converter having a lockup clutch, and an ECU for controlling selection of the power sources and for controlling a slip ratio of the torque converter. In this control device, a target slip ratio of the torque converter, which corresponds to a target amount of regeneration that is retrieved using regeneration amount determining factors, is obtained by executing a feedforward control operation using friction torque determining factors, and the slip ratio is controlled in a feedback manner based on the difference between the target slip ratio and the actual slip ratio.

The invention discloses a space rolling bearing comprehensive performance experiment device, relates to an experiment device and provides an experiment device capable of accurately measuring axial and redial united loads of a space rolling bearing and basic data including friction moment, bearing temperature rise, vibration and the like under different rotation speed working conditions. The space rolling bearing comprehensive performance experiment device can simultaneously conduct axial force and radial force accurate load on a measured bearing through an axial loading device and a radial loading device. A three-axis acceleration sensor is used for measuring radial, axial and peripheral vibration situations of the measured bearing. A temperature sensor is used for measuring the temperature rise situation of the measured bearing. A pressure sensor is used for measuring the friction moment of the measured bearing. An annular pressure sensor is used for measuring axial force borne by the measured bearing. Weights are used for marking radial force borne by the measured bearing. The space rolling bearing comprehensive performance experiment device can evaluate the comprehensive performance of the space rolling bearing and provide key scientific technical basis and test platform support for development of high-end bearings in the aerospace field of our country.

A transmitting apparatus includes a disengaging device that disengages a driving force from a front-wheel differential device to a first driving-force transmitting direction converting unit 20 and a multi-plate clutch mechanism provided between an output of a rear-wheel differential device and a right-rear wheel and capable of successively adjusting a fastening force. Drag torque when the fastening of the multi-plate clutch mechanism is released is set smaller than friction torque of a rear-wheel drive system between the first driving-force transmitting direction converting unit and a second driving-force transmitting direction converting unit. A controller unconnects the disengaging device and releases the fastening of multi-plate clutch mechanism when switching to a two-wheel drive mode, thereby stopping the rotation of the rear-wheel drive system.

In a motor-driven power steering apparatus, the main coil winding and auxiliary coil winding are wound around the same slot of a stator core in a parallel manner, a motor drive means has a main driver feeding at least to the main coil windings, and an auxiliary driver feeding only to the auxiliary coil windings, the main driver being actuated so as to be capable of assisting the steering during normal conditions of a control system of an electric motor, and the auxiliary driver is actuated so as to execute an auxiliary assist corresponding to a motor friction torque under abnormal conditions of the control system of the electric motor.

The present invention provides systems and methods of friction compensation in a steer-by-wire system or in a general electric steering system using control, estimation and modeling methodologies. A friction compensator in the steer-by-wire control system produces a friction compensating torque value equal and opposite in sign to the instantaneous friction torque. This compensating friction torque is added to the steering system control signal to eliminate the effects of friction present in the system such that the system performances are improved. The friction compensator produces the compensating friction torque according to one of two schemes: model-based or non-model based. The model-based scheme encompasses a number of different methods including a standard model-based scheme, a disturbance torque observer-based scheme, an adaptive friction compensation scheme, or a model reference adaptive control scheme. The non-model based scheme includes a fuzzy logic scheme.

The invention relates to a power driven system of the aircraft, which is characterized in that the power driven system comprises a power supply, a motor and a bearing support. The motor is vertically arranged in the bearing support by a bearing. Both the stator and the rotor of the motor are extending upwards and are respectively provided with propellers. The upper ends of the stator and the rotor where the propellers are arranged are coaxially sleeved, and the lower end of the rotor is fixed with a rotary disc after stretching out of the bearing support, an electromagnet with the magnetic pole part near the rotary disc is fixed-arranged outside the bearing support. When the motor is electrified, both the rotor and the stator drive the propellers to rotate to acquire power at the same time, and the power is transmitted to the frame by the bearing support to drive the aircraft to rise or advance. Meanwhile the electromagnetic moment between the electromagnet and the rotary disc is used to counteract the friction torque, and control the size of the electromagnetic moment to achieve the turning of the aircraft. The power driven system has the advantages of solving the problem of anti-torque of the propeller, satisfying the design requirements of miniature, simplification and lightness of the aircraft, and being beneficial to the popularization and manufacturing of the aircraft.

The invention relates to a torsional fretting friction wear test method, the method is that: an upper testing part is clamped in an upper clamp, a lower clamp is fixed with a high-precision low-speed rotation table by a thread, a vertical central line of a holding cavity of the lower clamp is aligned with a rotating shaft of the high-precision low-speed rotation table, a spherical lower testing part is clamped by the lower clamp; the upper clamp is controlled for up and down movements by a data collection control system, the upper and lower testing parts are contacted and are exerted by a set load, at the same time, the lower clamp and the lower testing part clamped by the lower clamp are controlled by the data collection control system to carry out a plurality of times of reciprocating rotations by a set rotation speed and a rotation angle; at the same time, the friction torque is measured by a six-dimension force/torque sensor which is connected with the upper clamp and is sent to the data collection control system, and a torque-angular displacement curve under the set rotation speed and the load conditions can be obtained by analysis. The method can conveniently allow the materials to generate the small angle torsional fretting friction wear, the degree of the automation is high, the precision of the control and the test is high and the reproducibility of the test data is good.

The invention relates to a friction torque testing device for a rolling bearing at low temperature. The friction torque testing device comprises a support and a pair of objective rolling bearings of same type, wherein the pair of objective rolling bearings of same type is mounted at two ends of a shaft so as to be placed in a sleeve, two ends of the sleeve are respectively located by a left end cover and a right end cover so as to be fixed on the support, and a temperature sensor is placed in a part of the sleeve near a drilling part of the objective rolling bearing so as to test the temperature variation of the bearing; an extending end of the shaft fixes a balance wheel through two set screws, two ends of each set screw are provided with two balance nuts to fine adjust the eccentricity of the balance wheel; a string comes around the balance wheel, and two trays are respectively hung on the two ends of the string; when weights are placed in the trays, a starting friction torque of the objective rolling bearing can be tested as soon as the balance wheel turns. The friction torque testing device for the rolling bearing at low temperature can effectively control certain pre-tightening force to test performance indexes of the friction torque of the bearing with different lubricants under different radial loads at low temperature; and the friction torque testing device is simple in structure, low in manufacturing cost and convenient to operate, and can repeatedly test the friction torque at harsh low temperature.

A driving force transmission device for four-wheel-drive vehicle based on the two-wheel drive of front wheels is provided. In the case of the two-wheel drive of front wheels, a multi-disc clutch mechanism for controlling the driving force distribution to a rear wheel output shaft, and a disconnection/connection mechanism for disconnecting and connecting a rear wheel differential and a right rear wheel drive shaft are provided, and in the two-wheel drive of front wheels, the dragging torque of the multi-disc clutch mechanism is made smaller than the friction torque of a rear wheel driving force transmission section, and the front wheel differential and the right rear wheel drive shaft are disconnected by the disconnection/connection mechanism, thereby the rotation of the rear wheel driving force transmission section is stopped.

The disclosed measuring apparatus and method for frictional moment comprise: the target bearing with diameter as D is suspended a segment nylon wire with ends connected to weight and dynamometer respectively, when bearing static, the show value on dynamometer as A1 balances to the weight; if rotating toward one direction by some rate, the show value increases to A2, and the formula M=(A2-A1) .D/2 can express the corresponding frictional moment. This invention is reliable, simple, and well practical.

The invention relates to a device for measuring friction torque of a bearing under different axial load and revolution speed, comprising a fixing component, an axial loading component, a display component and a measurement component arranged on a stander base, wherein, the measurement component is arranged in a bearing support by an upper bearing and a lower bearing which are the same and fixed on a stander workbench, a bushing on the workbench supports the end face of the bearing outer ring of the lower bearing, so as not to contact the end face of the inner ring, and a loading head presses the end face of the bearing outer ring of the upper bearing. The two same bearings are used for measurement so that the axial load is not directly applied to a transmission shaft and a driving device to influence and damage the operation of the driving device. The voltage of a direct current motor is adjusted by a voltage regulator, so as to adjust the rotate speed of the motor. The axial load is adjusted by rotating a screw. The device can measure larger and different load and bearings with higher and different rotate speed, has wide measurement range which can be adjusted, can meet different requirements of users, and has the advantages of simple structure, easy fabrication, convenient, accurate and intuitive operation and use, wide universality and strong practicability.

Algorithms for real-time estimation of the engine friction torque in a vehicle powertrain are disclosed. Engine friction torque is estimated at start and at engine idle. Recursive and computationally efficient algorithms allow prediction of friction torque for a wide range of speeds and loads even with few new measured points by taking into account physical dependencies used for adaptation of the sites of the look-up tables (static maps). The algorithms make it possible to avoid drivability problems that could result from errors in estimating engine friction torque.

An apparatus for measuring non contact type bearing start friction torque, is composed mainly of a loading cylinder (1), a force transducer (2), a loading housing (3), an air main shaft (5), an air bearing (6), a torque generator (7), a disk drive (8), an optoelectric transducer (9), an electrical system. The torque generator generates induction electromagnetic torque as drive torque, the optoelectric transducer monitors bearing start running state automatically; when being measured, the measured bearing is installed on the air main shaft, the disk drive is linked with the air main shaft and placed in the torque generator, the electrical system applies input power to the torque generator step by step after throwing axial load, when the induction electromagnetism drives the air main shaft to rotate through the disk drive, the optoelectric transducer matching-installed by the disk drive monitors the measured bearing from static state to start running state, and outputs signal to stop applying input power, and records current power value which is the start friction torque value of the measured bearing.

A motor-driven power steering apparatus is provided with a self-aligning torque computing means for computing a self-aligning torque based on of a steering angle and a vehicle speed, a friction torque computing means for computing a friction torque in accordance with a steering angle change from a steering angular velocity, an apparent steering torque computing means for computing an apparent steering torque from the friction torque and a steering torque, and a steering torque feedback control means for driving and controlling an assist motor in such a manner that a difference between the self-aligning torque and the apparent steering torque becomes 0.

The invention provides a megawatt wind power generation adjustable blade bearing friction moment numerical control testing machine and a testing method. The tested bearing outer ring is fixed on the machine rack; a main axis is equipped, one end of the bearing inner ring is fixed on the bearing inner ring, the other end is equipped with a radial and axial loading mechanism, in which the radial and axial load cylinder are separately pressured, and is equipped with variable-frequency motor of torque sensor, the driving pinion is meshed with the tested bearing inner ring, which form the loading and transmission system. The testing machine is determined by force analysis and analog loading principle, which is reasonable and reliable, and has simple structure and small size. The closed-loop numerical control system, which is composed of an industrial computer, a hydraulic pressure control member, a hydro cylinder, a feedback element and other components, can realize overall monitor, data collection, analysis, process, and number and graph double output; the size, direction, variation period of the load are accurate, the curves of the load output and friction torque are intuitive, the testing process is highly automatic. And the invention can be matched with manual adjustment. The machine is shutdown automatically if any failure happens. The test provides data support for the bearing wind turbines, which assures that the machine can meet the test need after loading.

The invention relates to a method for recognizing moment of inertia of asynchronous motor. For the purpose, following steps are taken. The electrical motor is controlled to run at constant acceleration from angular velocity omega 1 of no load operation to angular velocity omega 2 and recording the running time delta t by using control method of torque vector. By using control method of speed vector. The motor is controlled to run at constant angular velocity omega 3 of no load operation. The value of electromagnet torque is calculated based on the torque current component It at this time, so as to get the friction torque To of the motor. then based on the running time delta t and the friction torque Io, the moment of inertia Jo of the omtor is calculated. The invented method provides high accuracy for recognizing these parameters, thus improving the performance of the method of vector control.