GB2323184A

GB2323184A - Obstruction-sensing system for a movable member with temperature compensation

Info

Publication number: GB2323184A
Application number: GB9805436A
Authority: GB
Inventors: Hubert Lamm; Guenter Haderer
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1997-03-15
Filing date: 1998-03-13
Publication date: 1998-09-16
Anticipated expiration: 2018-03-13
Also published as: GB9805436D0; DE19710890A1; FR2762720A1; ITMI980397A1; GB2323184B; FR2762720B1; IT1298310B1

Abstract

Electric motor (10) drives a setting member (12), and there is a danger of wedging of an article or a body part such as in the case of a sliding roof or window of a motor vehicle. A controlling method comprises the step of determining a criterion for switching off or reversing the direction of the member subject to consideration of an operating parameter magnitude, such as motor speed, of the system. At least one ambient temperature of the system is also taken into consideration in determination of the criterion, in that the ambient temperature and/or a magnitude dependent thereon is or are detected and processed in a signal-processing arrangement (36).

Description

1 1 1 2323184 METHOD OF AND CONTROL MEANS FOR CONTROLLING A SETTING SYSTEM

The present invention relates to a method of and control means for controlling a setting system with a movable member driven by an electric motor.

A protective device for an electric motor, in which a magnitude having a relationship with the operating temperature of an electric motor is determined from the switch-on time and other operating parameters of the motor, is described in DE-PS 41 09 867. In that case, the ambient temperature of the motor is taken into consideration as an additional operating parameter. If the magnitude having the relationship with the operating temperature exceeds a presettable value, electronic means switch off the motor.

A device for control of the operation of a member, which is driven by an electric motor and where there is a danger of wedging of an article or a body part of a person between the member and an end abutment, is known from DE-OS 40 31 257. A signal-processing arrangement evaluates the rotational speed of the motor or associated drive. The speed is a parameter magnitude which, by virtue of its functional relationship with the torque of the motor or drive, has a relationship to the actuating force of the member. For correction of temperature influence on the functional relationship, there is provided a temperature sensor which detects an operating temperature at the motor, preferably the winding temperature. The mounting of a temperature sensor in the motor is however laborious and expensive. Furthermore, no account is taken of the fact that the movement characteristics of a system consisting of a member and an electric motor drive are influenced to a high degree by ambient conditions. The device in question thus cannot ensure full protection against wedging of articles or body parts in the case of different weather influences.

According to a first aspect of the present invention there is provided a method for the operation of a setting system with at least one electric motor drive and at least one setting member, for which the danger of wedging of an article andlor a body part exists, especially a sliding roof of a vehicle or a window, wherein a characteristic magnitude of the system is determined and a criterion for stopping or reversal of direction of the member is ascertained by a signal-processing arrangement subject to consideration of this characteristic magnitude, characterised in that the influence of at least one ambient temperature at the setting system is taken into consideration in determination of the 2 criterion in that the ambient temperature and/or magnitudes dependent thereon are detected and processed with others in the signal-processing equipment.

A method exemplifying the invention may have the advantage that the criterion for stopping or reversal of direction can be adapted in optimum manner to all temperature ranges occurring at the system or at parts thereof The method recognises that ambient temperatures of the system have a not insignificant influence on its behaviour. Whereas large safety margins must normally be present for observance of a legally fixed maximum force of the member when acting on an article or a body part without consideration of the ambient temperature, such margins may be able to be reduced in a method exemplifying the invention. The system can thus operate to its maximum possible effect for given conditions.

Different ambient temperatures, caused for example by shadow, varying thermal conductivity, partial air cooling and other effects on the thermal behaviour of the environment, can arise at the system. Thus, some regions of a sliding roof of a motor vehicle may be thermal contact with a metallic frame and other regions in thermal contact with a rubber seal. In addition, a glass panel of a sliding roof has much smaller thermal conductivity than a metallic setting mechanism for the movement of the glass pane and therefore as a rule has a different temperature.

However, the substantially uniform external temperature of the system can also be taken into consideration as ambient temperature, for example the temperature of the air surrounding the system or a part thereof.

Since the operating characteristics of the motor depend on its operating temperature, the ambient temperature of the motor influences the criterion. Consideration of at least one ambient temperature of the motor is therefore of advantage for the determination of the criterion.

Moreover, the temperature of the member caused by, for example, thermal expansion or contraction of its mechanical components and the changing sliding effect of the lubricants used has an effect on its movement characteristics. Different levels of force can, according to ambient temperature, counteract the driving force delivered to the member.

3 Advantageously, therefore, at least one ambient temperature of the member is taken into consideration in determination of the criterion.

The method is preferably applied with determination of the operating temperature of the motor from motor operating parameters by electronic means, thus indirectly. The winding temperature of the motor is preferably taken as operating temperature. As has already been mentioned, the drive power delivered by the motor is dependent on its operating temperature. However, the mounting of a temperature sensor directly in the motor, for example at the armature windings, is difficult. Extrapolation of the operating temperature in dependence on operating parameters, for example the motor voltage, switch-on duration, switch-off duration and so forth, is substantially simpler to realise. Since the operating temperature of the motor depends on its ambient temperature, its actual operating temperature and thereby the delivered drive power can be estimated substantially more accurately.

In addition, means can be provided to switch off the motor when the ascertained operating temperature exceeds a predetermined temperature limit. The switching-off then takes place in dependence on the ambient temperature. Faulty triggering of a thermal protection of that kind is largely avoided by virtue of the more accurate extrapolation of the operating temperature.

If the determined characteristic magnitude has a relationship with the drive power of the motor, this relationship can be derived from the magnitude. The actual drive force of the member can then be compared with a legally prescribed maximum value for such force.

Preferably, the criterion is fulfilled when at least one magnitude, which is derived from the characteristic magnitude, exceeds a predetermined maximum value. The method can thereby be easily performed by, for example, electronic means or a program-controlled microprocessor. Expediently, this maximum value can be fixed in dependence on the ambient temperature. This permits the consideration of different effects, which are caused by ambient temperature, in the maximum value. With advantage, the maximum value is resolved into a part independent of and a part dependent on ambient temperature. The functional integrity of the motor control is then ensured even in the case of a defect in the ascertaining of the ambient temperature, since that part of the maximum value which is independent of temperature is correctly fixed in every case. Moreover, identical control 4 units can be configured for installation in systems with and without consideration of the ambient temperature, so that the product range to be kept in stock is reduced.

The correction value dependent on ambient temperature can be read out of a store of the signal-processing arrangement. This is expedient particularly when the computation of the correction value is laborious and a sufficient amount of storage space is available. The signal- processing arrangement can in that case be built up from components which are favourable in cost. Expediently, the correction value is stored in the form of a table divided into ambient temperature ranges, so that it is not necessary to use an algorithm for ascertaining the required correction value.

The correction value can, however, be computed by the signal-processing arrangement or determined by electronic means. This is preferably so when the sign al-processing arrangement has no storage capability or the computation is not extensive or critical in time.

For preference, the rotational speed of the motor is utilised as the characteristic magnitude and the functional relationship between the rotational speed and the torque of the motor is employed for determination of the criterion. As additional parameter, for example the operating voltage of the motor can then be taken into consideration. It is, however, also feasible for the motor current or a magnitude derived therefrom to be the characteristic magnitude.

According to a second aspect of the invention there is provided control means for operation of a setting system with at least one electric motor drive and at least one setting member, for which the danger of wedging of an article and/or a body part exists, comprising means for the determination of a characteristic magnitude of the system and a signalprocessing arrangement which from this characteristic magnitude ascertains a criterion for stopping or reversal of direction of the member subject to consideration of at least one ambient temperature of the system, wherein at least one temperature sensor is provided to detect the ambient temperature of a part of the system.

The presence of a sensor enables detection, at favourable cost, of the ambient temperature for the determination of the criterion.

If the motor drive is arranged in the proximity of the member, both may have substantially the same ambient temperature. The temperature sensor can thereby detect the ambient temperatures, which are relevant to the criterion, of both components at the same time.

Preferably, the member is a sliding roof or window of a motor vehicle. Ambient temperature, which is variable due to weather, can in that case have a significant effect on the dynamics of the member.

An example of the method and embodiment of the control means of the invention will now be more particularly described with reference to the accompanying drawings, in which:

Fig. 1 is a schematic block diagram of control means embodying the invention; and Fig. 2 is a flow chart showing the steps in a method exemplifying the invention.

Referring now to the drawings, there is shown in Fig. 1 a setting system comprising an electric motor drive with an electric motor 10 and a downstream transmission 11, which moves a member 12 in the form of a sliding roof of a motor vehicle in the direction of the double arrow 13. On approach of the member 12 to an abutment 15, the risk of the wedging of a body part or an article exists between the member and the abutment. An electronic system mounting plate 34 is arranged in the proximity of the motor 10, for example in a housing fastened to a motor casing. A signal-processing arrangement 36, which comprises a microcontroller with associated freely selectable (RAM) and nonvolatile (ROM) storage devices and different interfaces, is disposed on the plate 34. The arrangement 36 controls the motor 10 by way of a drive circuit 38. At least one Hall sensor 40 is arranged, as a rotational speed sensor, in the motor 10. The signals of the sensor 40 are evaluated by the arrangement 36 by way of first interfaces 42. A temperature sensor 43, the data of which are read into the arrangement 36 by way of second interfaces 44, is arranged on the plate 34. The sensor 43 is connected with electronic means 45 for extrapolating an operating temperature TM of the motor, as described in DE-PS 41 09 867, from the ambient temperature measured by the sensor 43, the supply voltage U of the motor 10, the operating and cooling-down period of the motor and other operating parameters. The arrangement 36 reads in the result by way of third interfaces 47. Since the plate 34 is disposed in the proximity of the motor 10 and member 6 12, the sensor 43 approximately detects the ambient temperatures of both components. The arrangement 36 receives setting commands by way of input means 46.

Operation of the above-described control means, in program-controlled manner, of the setting system is illustrated by Fig. 2. After the start 100 of a setting operation, which is initiated by the actuation of the input means 46, the signals of the sensor 40 are read in by way of the first interfaces 42 in a step 102 and the rotational speed n of the motor is determined therefrom. In a following step 104, the ambient temperature Tu detected by the sensor 43 and the operating temperature Tm, which is ascertained by electronic means, of the motor 10 are read in by way of the second interfaces 44. From the operating temperature Tm and the rotational speed n, as characteristic magnitude of the setting system, a magnitude F(Tm,n), which stands in relationship with the drive power of the motor, is ascertained in a step 106 by way of a characteristic field filed in the ROM storage device. In a following method step 108, a correction value K(Tu) dependent on the ambient temperature Tu as well as a maximum value Go, which is dependent on the ambient temperature and filed in another region of the ROM device, are read in by way of a table 110 filed in the ROM device. The table 110 is divided into ambient temperature ranges To to TN, of equal size. To is the lowest ambient temperature to be expected and TN the highest ambient temperature to be expected. The ranges are associated in the table with constant correction values K(To) to K(TN), respectively. The dependence of the movement behaviour of the member 12 is taken into consideration in the case of the correction values K; for example the force, which is exerted on an object wedged between the abutment 15 and the member 12, can for the same torque M be smaller for a cold member than for a warm member when greater frictional forces act on the member in its guides or bearings by reason of thermal contraction, solidification of lubricant and so forth.

The signal-processing arrangement 36 adds the correction value K(Tu) to the maximum value GO in a step 112 and thus determines the maximum value G(Tu) dependent on ambient temperature. In a step 114, the magnitude F(Tm, n) is compared with the maximum value G(Tu) dependent on ambient temperature. If the magnitude F(Tm,n) is greater than the maximum value G(Tu), the criterion is fulfilled and the method branches to a step 120, where the motor is stopped or reversed. Otherwise, the method is repeated from the step 102 until the demanded setting operation is concluded.

7 Other forms of the method are also feasible. For example, the correction value K(Tu) dependent on ambient temperature can be computed by the arrangement 36 by means of a preset function translated into a program for the arrangement.

Moreover, the operating temperature Tm of the motor can be ascertained not by electronic means, but directly by the arrangement 36.

Furthermore, the possibility exists of arranging several ambient temperature sensors at the system. This may be desirable particularly when the member is exposed to different ambient temperatures, which may cause straining of the system mechanism and thus influence the drive power by which the member 12 is moved against an abutment 15.

8

Claims

1. A method of controlling a setting system in which a movable member driven by an electric motor can encounter obstruction to movement, the method comprising the steps of determining an operating parameter magnitude of the system, detecting at least one ambient temperature at the system, and determining a criterion for stopping or reversing the drive of the member in dependence on the operating parameter magnitude and at least one of the ambient temperature or temperatures and a magnitude or magnitudes dependent on the ambient temperature or temperatures.

2. A method as claimed in claim 1, wherein the at least one ambient temperature is at the motor.

3. A method as claimed in claim 1 or claim 2, wherein the at least one ambient temperature is at the member.

4. A method as claimed in any one of the preceding claims, wherein the step of determining the operating parameter magnitude is carried out in dependence on the operating temperature of the motor.

5. A method as claimed in claim 4, comprising the step of determining the operating temperature of the motor by electronic means in dependence on operating parameters of the motor.

6. A method as claimed in claim 4, comprising the step of determining the operating temperature of the motor in dependence on the at least one ambient temperature.

7. A method according to any one of the preceding claims, wherein the operating parameter magnitude is dependent on the drive power of the motor.

8. A method as claimed in any one of the preceding claims, wherein the step of determining a criterion comprises recognising the criterion as fulfilled when a magnitude derived from the operating parameter magnitude exceeds a predetermined magnitude.

9 9. A method as claimed in claim 8, wherein the predetermined magnitude is dependent on the at least one ambient temperature.

10. A method as claimed in claim 9, comprising the step of fixing the predetermined magnitude by interlinking a value independent of and a correction value dependent on temperature.

11. A method as claimed in claim 10, comprising the step of selecting the correction value from a plurality of stored values.

12. A method as claimed in claim 11, wherein the stored values are each associated with a respective temperature range.

13. A method as claimed in claim 10, comprising the step of calculating the correction value.

14. A method as claimed in any one of the preceding claims, wherein the operating parameter magnitude is the rotational speed of the motor and the step of determining the criterion is carried out in dependence on the relationship between the rotational speed and the torque of the motor.

15. A method as claimed in claim 14, comprising the step of determining said relationship by reference to a stored characteristic curve.

16. A method as claimed in claim 14, comprising the step of determining said relationship by reference to a plurality of characteristic curves stored as a characteristic curve field with value parameters at least of motor temperature and ambient temperature.

17. A method as claimed in any one of claims 14 to 16, comprising the step of determining the motor rotational speed by means of at least one Hall sensor arranged at the motor.

18. A method as claimed in any one of claims 1 to 13, wherein the operating parameter magnitude is a magnitude indicative of an operating parameter of the member.

19. A method as claimed in any one of the preceding claims, wherein the member is a sliding roof or a window in a motor vehicle.

20. A method as claimed in claim 1 and substantially as hereinbefore described with reference to the accompanying drawings.

21. Control means for controlling a setting system in which a movable member driven by an electric motor can encounter obstruction to movement, comprising means for determining an operating parameter magnitude of the system, detecting at least one ambient temperature at the system, and determining a criterion for stopping or reversing the drive of the member in dependence on the operating parameter magnitude and at least one of the ambient temperature or temperatures and a magnitude or magnitudes dependent on the ambient temperature or temperatures.

22. Control means as claimed in claim 21, wherein the means for determining the at least one ambient temperature comprises a temperature sensor.

23. Control means as claimed in claim 22, wherein the means for determining the criterion comprises electronic signal processing means, the signal processing means and the sensor being mounted on a common mounting plate.

24. Control means substantially as hereinbefore described with reference to the accompanying drawings.

25. A setting system provided with control means as claimed in any one of claims 21 to 23.

26. A system as claimed in claim 25, wherein the control means is as claimed in claim 23 and the plate is mounted at the motor.

27. A system as claimed in claim 25 or claim 26, wherein the motor is mounted adjacent to the member.

28. A system as claimed in any one of claims 25 or claim 27, wherein the member is a sliding roof or a window of a motor vehicle.

11

29. A motor vehicle provided with a system as claimed in any one of claims 25 to 28.