Electricity: motive power systems – Automatic and/or with time-delay means – Speed or rate-of-movement
Reexamination Certificate
1999-07-26
2001-05-01
Ro, Bentsu (Department: 2837)
Electricity: motive power systems
Automatic and/or with time-delay means
Speed or rate-of-movement
C318S490000, C318S464000, C388S902000
Reexamination Certificate
active
06225770
ABSTRACT:
FIELD OF THE INVENTION
The invention concerns the process for the control of motor driven adjustment devices in motor vehicles. These control devices may, for example, be a window lifter, a sun roof control, or a seat adjustment device.
BACKGROUND OF THE INVENTION
From U.S. Pat. No. 5,404,673, a window lifter with a drive to raise and lower a window pane and with an entrapment protection device is known. The speed of the drive and thus the opening and closing speed of the window pane, as well as the direction of movement and position of the window pane, are detected. Upon entrapment of a body part or object between the top edge of the window pane and the door frame, the load on the drive increases, and the drive speed drops below a predefined value. The drive turns off and possibly reverses, and results in the stopping or opening of the window pane.
Since upon entry of the window pane into the door seal before complete closing of the window pane, the drive speed drops to the point of stopping the drive because of the increased resistance, the pane position must be accurately detected, so that the entrapment protection turns off in the seal zone.
For this, a sensor for sensing a position and direction of rotation is provided. The sensor for sensing the direction of rotation consists of a magnetic disk with a north and south pole as well as two Hall sensors offset an angle of 90° relative to each other around the axis of the magnetic disk connected to the drive shaft, which emit sensor signals offset from each other by one-fourth period, from which the direction rotation and thus the direction of movement of the window pane is determined.
The position sensor consists of an annular multipole magnet connected to the drive shaft with alternatingly magnetized magnetic poles and two Hall sensors, which are disposed at a distance of one-half magnetic pole from each other. The magnetization alternation detected by the Hall sensors during a rotation of the drive, and with it that of the annular multipole magnet, are fed as counting pulses to a counter along with the sensor signal of the direction of rotation sensor, whereby the counting pulses are counted upward or downward depending on the direction rotation of the drive, and thus indicate the respective position of the window pane.
For detection of the speed, direction of movement, and position of the window pane, the known drive control and entrapment protection device requires two magnetic disks as signal generators with four Hall sensors. The signal generator provided to trigger the entrapment protection criterion by reducing the speed of the drive has only low resolution with one pole change per revolution.
For speed control of rotating drives, or with a linear adjustment such as a seat distance adjustment to obtain a constant adjustment speed over the adjustment path, a high-resolution sensor system is necessary to enable short reaction times in the control process. However, partitioned signal generators, such as multipole magnets, are subject to tolerances which may have a negative effect on control behavior.
If, consequently, to increase the resolution in the detection of the speed of electric motor, a multipole magnet is used as a signal generator, the problem arises that with rotation magnets with more than two poles, the distribution of the poles on the magnet is not exactly symmetric, but has an error of approximately 10% per sector. This error rate holds in general for all signal generators for speed detection sensors which cannot be manufactured exact enough and operate with an optoelectric, inductive, capacitive sensor, etc. as the signal receiver.
The tolerances described and manufacturing-related errors from section to section of the signal generator or from sector to sector in a circular disk-shaped signal generator result in misinterpretations in the signal evaluation. For example, due to misinterpretations, a drop in speed is detected although the drive is operated at a constant speed, and possibly, erroneous reactions of the control arrangement of the adjustment device result, for example, an erroneous reversing of a window pane due to defective detection of a speed sensor results, which is interpreted as an entrapment situation by an entrapment protection device.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a process for control and regulation of motor driven adjustment devices in motor vehicles which ensures exact detection of position, speed, or acceleration of the drive with high-resolution of the measured values without imposing particularly high accuracy specifications on the signal generator.
The process according to the invention ensures high-resolution and accuracy of the measured values for detection of the position, speed, and/or acceleration of a drive. Since, with the object of the present invention, the tolerances are determined and considered in signal evaluation on a partitioned basis, measurement errors caused by inaccuracies of the signal generator due to manufacturing difficulties are greatly reduced or eliminated such that use of signal generators without particularly high quality specifications is possible. Thus, use of less exact components in signal generation and detection is possible.
In particular, it is possible to use components whose manufacturing accuracies are limited for systemic reasons, such as manufacturing precision, i.e., the sector size and magnetization strength of electromagnetic signal generators in conjunction with magnet-sensitive structural components, such as detectors in the form of Hall sensors. In signal generators, the tolerances may exist in the partitions. In detectors (in the form of one or a plurality of sensors) the tolerances may exist in the electrical tolerances, for example, the hysteresis of the switching thresholds in Hall sensors.
Consequently, with a low expenditure on device-engineering, it is possible to realize high-resolution position, rotational speed, velocity, or acceleration controls.
The process according to the invention can be implemented both by means of electronic error correction or by switching technology. For electronic error correction only a single sensor is required.
With electronic error correction, the tolerance-associated characteristics of the signal generator partitions are preferably determined in a test movement of the signal generator.
Additional requirements for a process for control of an adjustment device result if, for example, the speed of a seat adjustment device is to be controlled. In this case, in addition to the setting of a constant speed (ideal speed) in the operating point of the motor, a uniform, vibration-free starting and takeoff of the seat is important. The operating point of the motor of the seat adjustment device is defined under consideration of the resonance frequencies of the seat unit consisting of the drive motor, adjustment drive, and mechanical seat components as well as the vehicle body. In addition, data with regard to the speed of the seat to be adjusted as well as an adjustment energy reserve must be taken into account.
No movements or noises which disturb the vehicle occupants should occur during starting and stopping of an electrical seat adjustment device due to the starting or stopping of the seat. Moreover, the most wear-free operation of the seat adjustment device is desirable in terms of savings of materials.
According to another aspect of the invention, there is the object of providing a process for the control of motor driven adjustment devices in motor vehicles, which enables precise detection of position, speed, and possibly acceleration of the drive with high-resolution of the measured values, on the one hand, and which permits quiet, uniform starting and takeoff of the adjustment device, on the other.
Provision is made accordingly, that after activation of the drive motor, first tolerance-associated characteristics values of the signal generator are determined, and correction values which are to be considered in the evaluation of the output signals of th
Eichhorn Mike
Heinrich Peter
Brose Fahrzeugteile GmbH & Co. KG
Christie Parker & Hale LLP
Ro Bentsu
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