DE102004039738A1 - Dynamic gear state change detecting method for use in motor vehicle, involves calculating state variables of gear from speed signals for diagnostics purpose, and evaluating measurement signals to simulate physical system performance of gear - Google Patents

Abstract

The method involves calculating state variables of a gear from speed signals for diagnostics purpose, and evaluating the measurement signals in a gear model. The evaluation of the measurement signals simulates the physical system performance of the gear. The deviation of measured variables from variables calculated in the gear model is used for detection change of system parameters.

Description

The The present invention relates to a method for detecting dynamic state changes in vehicle transmissions according to the preamble of Patent claim 1.

To In the prior art, the signal-oriented state diagnosis is based of machines on the principle of changes in dynamic system behavior, which can be detected with suitable sensors. The causes of a change the dynamic system behavior can external influences, for example unwanted vibrations in a drive train, or internal changes, such as Damage, wear, material fatigue, etc. be. These influences to lead usually to modulations of the state variables. Typical, commonly used State variables are Speeds, torques, forces and resulting movements, such as vibrations. model-based Methods for determining state variables for control purposes can be found in US Pat industrial drive technology application.

in this connection have to the necessary sensors will be able to do that for the dynamic Behavior characteristic frequency range of the machine including the additionally generated by the disturbing influences To record frequency components.

Of the The present invention is based on the object, a method for detecting dynamic changes of state in vehicle transmissions specify which essentially uses speed sensors. Especially should the changes in dynamic system behavior in vehicle transmissions with high accuracy be detected.

These The object is solved by the features of claim 1. Further Embodiments of the invention and advantages are apparent from the dependent claims.

Therefore It is proposed to one or more speed signals more To calculate state variables and for To use diagnostic purposes, wherein the evaluation of the measurement signals in a transmission model, which determines the physical system behavior of the gearbox simulated. Here, the deviations are measured Sizes of calculated sizes to Detection of changes used by system parameters.

to Measurement of the speeds can be any known from the prior art and appropriate methods are used. As part of a special advantageous development is proposed as a difference time analysis apply the specified method, wherein the instantaneous speed from the angular velocity of at least one on the shaft, whose Speed to be measured, arranged impulsive marking is calculated within a time interval, where the impulsive Marking at two, relative to the center of rotation of the to be detected Rotational motion, radially close together and with the markings interacting and impulsive sensors is passed.

in this connection The sensors generate a pulse train, the pulse train of the second sensor opposite the pulse train of the first sensor shifted by a difference time is, such that at a known angle between the sensors, related on the center of rotation of the rotational movement to be detected, and known Difference time the angular velocity is calculated.

By the conception according to the invention can be calculated quantities for regulatory purposes, for example used for torque control. In addition, by adaptation the simulation parameter the detection of system changes, caused by wear were made possible. In an advantageous way also damages at load-carrying Components (for example, pitting on tooth flanks, cracks, bearing damage) recognized become. Furthermore, you can unacceptable Vibration loads due to external influences (e.g. Wear of attenuators in the drive train).

According to one particularly advantageous variant of the method according to the invention become from the obtained speed signals, the angular acceleration calculated, which serve as input signals for a mathematical model, which simulates the physical system behavior of the gearbox. The Angular accelerations can also calculated in the transmission model from the obtained speed signals become.

in this connection are used within the framework of the simulation or the calculation model as internal Sizes further state variables, preferably Torques and forces, gained indirectly. According to the invention that Simulation model by comparing calculated and measured Speed values with regard to the accuracy of the model parameters checked and corrected under real-time conditions become. Subsequently be by means of a downstream demodulator (frequency and Amplitude demodulation) for a diagnosis relevant information from the calculated and measured Extracted sizes.

The invention will be explained in more detail below by way of example with reference to the attached figures. It demonstrate:

1 a block diagram illustrating the essential steps of a particularly advantageous variant of the method according to the invention; and

2 an application example of the method according to the invention.

According to 1 On the one hand, the input rotational speed Nan and, on the other hand, the output rotational speed Nab are measured, this preferably taking place by means of the differential time analysis. In this case, the rotational speed is calculated from the angular velocity of at least one pulse-emitting marking, the pulse-emitting marking being guided past two sensors which are arranged radially close to one another and cooperate with the markers and impart pulses.

in this connection The sensors generate a pulse train, the pulse train of the second sensor opposite the pulse train of the first sensor shifted by a difference time is. From the difference time and the angle between the sensors, relative to the center of rotation of the rotational movement to be detected, the angular velocity is calculated. Preferably be around the waves attachable impulse-giving bands used, which is a structuring in the form of substantially regular markings; the marks may be, for example, black and white color coats, act strip-like magnetizations or tooth-like structures, which interact with corresponding sensors.

The measured drive speed serves as input for a physical system behavior simulating transmission model and downstream of the transmission model Diagnostic module comprising a demodulator; the measured drive speed serves as input for the diagnostic module, where the difference between the measured output speed and the calculated output speed used as an input to the transmission model becomes. As a further input variable for the transmission model serves the bottom temperature.

in the Gearbox models are the corresponding angular acceleration from the speeds calculated as the basis for the calculation of further state variables, in particular the drive torque Tan, the output torque Tab, the target output speed and forces for example, bearing forces Serve FL.

By the method according to the invention is a state diagnosis, in particular a transmission 1 of a motor vehicle 2 , as in 2 exemplified, allows, which maps the state of the transmission with high accuracy.

Nan

Input speed

Nab

Output speed

Tan

drive torque

tab

output torque

FL

bearing forces

1

transmission

2

motor vehicle

Claims (7)

Method for detecting dynamic state changes in vehicle transmissions, where one or more speed signals State variables of the Gear calculated and for Diagnostic purposes are used, the evaluation of the measurement signals is done in a transmission model, the physical system behavior of the Gear simulated. Method for detecting dynamic state changes in vehicle transmissions according to claim 1, characterized in that the deviations of measured quantities of in the gearbox model calculated sizes for Detecting changes from System parameters are used. Method for detecting dynamic state changes in vehicle transmissions according to claim 1 or 2, characterized in that that from the obtained speed signals, the angular acceleration which are either input signals to the transmission model serve or be calculated in the transmission model. Method for detecting dynamic state changes in vehicle transmissions according to claim 1, 2 or 3, characterized that in the transmission model state variables of the transmission, in particular the drive torque Tan, the output torque Tab, the target output speed and bearing forces FL are calculated. Method for detecting dynamic state changes in vehicle transmissions according to one of the preceding claims, characterized characterized in that the transmission model is calculated by a comparison of and measured speed values with respect to the accuracy of the model parameters checked and corrected under real-time conditions becomes. Method for detecting dynamic state changes in vehicle transmissions after a of the preceding claims, characterized in that the transmission model, a diagnostic module comprising a demodulator for frequency and amplitude demodulation, downstream, wherein in the diagnostic module relevant for a state diagnosis information from the calculated and measured variables are extracted. Method for detecting dynamic state changes in vehicle transmissions according to one of the preceding claims, characterized in that a method is used to measure the speeds is, in the context of which the speed of the angular velocity is calculated at least one impulsive marking, wherein the impulsive marking on two radially close together and with the markers cooperating and impulsive sensors past is, wherein the sensors generate a pulse train, wherein the pulse train the second sensor opposite the pulse train of the first sensor shifted by a difference time is such that the angular velocity of the difference time and the angle between the sensors, based on the center of rotation the rotational movement to be detected, is calculated.