WO1991010800A1

WO1991010800A1 - Process and device for operating externally powered components in which a body part or other object could be caught

Info

Publication number: WO1991010800A1
Application number: PCT/DE1990/000992
Authority: WO
Inventors: Hubert Lamm; Stefan Kiefer; Gerhard Knecht; Gert Mau; Rainer Zottmaier
Original assignee: Robert Bosch Gmbh; Reitter & Schefenecker Kg; Domatic Gmbh
Priority date: 1990-01-12
Filing date: 1990-12-22
Publication date: 1991-07-25
Also published as: CS3991A2; DE4000730A1

Abstract

Proposed are a process and device for operating externally powered components with which there is the danger of a body part or other object being caught in the component. At least one derivative is calculated of a parameter which is related to the power necessary to operate the unit with respect to the distance travelled by the component. If at least one given threshold is exceeded, the component is switched off or its direction of motion reversed.

Description

Method and device for operating power-operated parts with risk of pinching

State of the art

The invention relates to a method and a device for the operation of power-operated parts, in which there is a risk of objects or body parts being jammed by persons. DE-PS 30 34 118 discloses a method for electronically monitoring the opening and closing process of electrically operated window lifters and sunroofs in motor vehicles. The path to be followed during the opening and closing process of the moving part is divided into several areas. In a first and third area, the electric motor of the drive is switched off as soon as a time limit value is reached when a blocking state occurs, which is determined by a speed detection of the drive. In a second area, measured values dependent on the speed or the speed of the moving part or the drive motor are continuously determined during the closing operation and compared with a limit value related to an initial measured value. If the limit value is exceeded, the drive direction of the electric motor is briefly reversed and then the drive is switched off. The distance traveled by the moving part is determined by integrating a speed signal in a signal processing arrangement. The invention is based on the object of specifying a method and a device for operating power-operated parts, which reliably detects the jamming of objects or people by the part under all operating conditions and immediately initiates countermeasures.

Advantages of the invention

The method and the device according to the invention initially provide for the detection of a parameter which is related to the actuating force of the part and the path covered by the part. Subsequently, at least one derivation of the course of the parameter along the path is determined. Derivation is understood to mean the formation of the differential quotient with analog and the formation of a difference quotient with digital calculation. Exceeding a limit value which is predetermined for the result of the at least one derivation leads to the part being switched off and / or to the reversal of the direction of movement.

Already the formation of the first derivative allows a pinching process to be recognized with a high degree of certainty. The additional or alternative determination of higher derivatives, preferably at least the second derivative, further increases the reliability of the detection, because changes influence the result more than in the first derivative. If more than one derivation is formed, each result must be compared with its own limit value, whereby the limit values can be different. The part is then switched off or the direction of movement is reversed if a limit value is only exceeded. The method and the device according to the invention have the advantage that the speed of the actuated part can be disregarded. The speed of the part can therefore vary within wide limits over the entire distance covered, as long as the result of at least one derivation does not exceed the predetermined limit value. The method and the device according to the invention are suitable for operating sliding doors and other stationary power-operated parts in which there is a risk of objects or body parts being trapped by people. In particular, it is suitable for operating sunroofs, window regulators, door closing aids and belt hangers in motor vehicles. In assembly technology, it is particularly advantageous to use power-operated handling machines. It is also suitable for operating roller shutters and barriers, in particular parking space reservation parts.

Further developments and improvements of the method and the device according to the invention result from subclaims. If more than one derivative, for example the first and second, are calculated, there is a simplification by combining the results of the derivatives and a subsequent comparison with a limit value. The results can be summarized, for example, by an addition, the sum being compared with the limit value.

A particularly advantageous development of the method according to the invention and the device provides for several determinations of at least one derivation, based on different paths. With this measure, it is possible to adapt to different objects or body parts of people whose jamming is to be prevented. The different hardness of objects or parts of the body leads to hard or correspondingly soft pinching processes, which are noticeable differently in the change in the parameter, based on the path. For example, a determination of at least one derivative matched to a hard pinching would not recognize a soft pinching. With the further development, the beginning of the jamming of different objects can thus be recognized as quickly as possible. It is already sufficient to calculate the first derivatives in each case. An increase in Detection reliability is also possible here by determining higher derivatives, preferably the first and second derivatives. The results of the several calculations of the derivatives running in parallel are each compared with a limit value. If the first and / or higher derivatives are also determined, separate limit values are also provided for these results.

If different derivations are determined in the method according to further development, a summary of the first and / or higher derivations and a subsequent comparison with a single limit value is also possible here. For the parallel running calculations, only as many limit values have to be provided as the calculations are carried out.

According to an expedient embodiment, the adaptive determination of limit values by pinching tests is provided. With this measure, it is possible to specify optimal limit values for each individual part.

A further improvement of the method and the device according to the invention relates to a division of the entire adjustment path of the part into several partial areas, each of which is assigned its own limit values. The division into several sub-areas allows taking into account different dimensions of the objects or body parts of the people.

Signal filtering in the detection of the course of the parameter increases the reliability of the method and the device against mechanical effects on the part, such as vibrations and the resulting high-frequency interference signal components. High-frequency interference signals would come into play when determining higher derivations and possibly simulate a pinching process. The method according to the invention is particularly easy to implement if the speed of a drive of the part is used as the parameter, which is detected by a sensor. The distance traveled by the part can then be calculated in a simple manner by integrating the speed signals.

A further improvement of the method and the device according to the invention is possible by specifying a minimum speed below which the part is switched off or the direction of movement is reversed. The additional monitoring for a minimum speed also precludes the prevention of objects or body parts from being trapped if it is no longer possible to determine at least one derivation because the speed is too low to be able to detect a significant change.

A simple realization of the part is possible with an electromotive drive.

A particularly advantageous development of the method according to the invention and the device when using an electromotive drive provides for a correction of the detected speed as a function of the operating voltage. A change in the speed can be caused both by a pinching and by a change in the operating voltage, a distinction between the two causes in a signal processing arrangement without the corresponding correction of the detected speed depending on the operating voltage not being readily possible . This correction is particularly simple when using a direct-current motor drive, since a change in the operating voltage results in a parallel shift of the speed-torque characteristic curve, which is linear in the area of interest, the increase in speed in the working area under consideration being linearly dependent on the Operating voltage change. The correction value then depends on the measured voltage, which is multiplied by a constant value. Further details and advantageous developments of the method and the device according to the invention result from further subclaims in connection with the following description.

drawing

FIG. 1 shows a block diagram of a drive of a power-operated part and FIG. 2 shows a functional relationship between the speed and torque of a DC electric motor at different operating voltages.

FIG. 1 shows an electric motor 10 which is controlled by a signal processing arrangement 11 via a motor driver circuit 12. A sensor 13 detects the speed of the motor 10 and forwards it to the signal processing arrangement 11. Instructions for controlling the motor 10 are given to the arrangement 11 via an operating device 14. Furthermore, the arrangement 11 can give signals to the operating device 14 which are displayed there, for example. As a further input variable, the arrangement 11 is supplied with the operating voltage of the electric motor 10 which is detected by a voltage measuring device 15 and which can be determined, for example, from the motor driver circuit 12. The electric motor 10 drives a part, not shown, in which there is a risk of objects or body parts being trapped by persons.

FIG. 2 shows a functional relationship between the speed n and the torque M of a direct current electric motor. Three characteristic curves 16 are entered, which apply at different operating voltages U of the electric motor 10.

The method according to the invention and the device for operating power-operated parts in which there is a risk of objects or body parts being pinched are explained in more detail with reference to the block diagram shown in FIG. 1 and the functional relationship shown in FIG. 2: The electric motor 10 drives a part to be actuated, not shown in the figure, in which there is a risk of being pinched. Instead of the electric motor 10 shown in FIG. 1, a pneumatic or hydraulic drive can be provided for the part. It is essential to record a parameter that is related to the actuating force of the part. For this purpose, the sensor 13 is provided in FIG. 1, which detects the speed n of the motor 10, for example. Instead of the engine speed, another speed, for example on a transmission, can be detected. For a given speed n, a specific torque M, and thus an actuating force, can be specified from FIG. 2 on the basis of the characteristic curve. The functional relationship shown in FIG. 2 applies to a direct current electric motor, the operating voltage U for the three different characteristic curves 16 being taken into account as parameters.

In the signal processing arrangement 11, at least one derivation based on the distance traveled of the part is determined from the course of the parameter. If the speed of the drive 10 is used as a parameter, the distance covered can be obtained by integrating the speed signal. At least one derivation is continuously determined during the operation of the part and the result is compared with a predefinable limit value. If the limit value is exceeded, the direction of movement of the drive 10 is switched off or reversed. The first derivative is preferably determined. In addition or as an alternative, higher derivatives, preferably at least the second derivative, are determined. The inclusion of higher derivatives, possibly alongside the first derivative, increases the detection reliability of a pinching process, since changes in the characteristic variable in relation to the distance covered are more noticeable with higher derivatives than with the first derivative. Provided that the determination of several leads is provided, several limit values can be specified, whereby after only one limit value is exceeded, the direction of movement is switched off or reversed. If several derivatives are calculated, the evaluation procedure is simplified when comparing them by summarizing the results of the derivatives. A summary is made, for example, by adding the results of the individual derivatives and then comparing the sum with a single limit value.

Advantageously, several determinations of at least one derivation are provided in relation to different paths of the part, the results of the derivations being compared in each case with a predetermined limit value. With this measure it is possible to take into account different hardnesses of a pinched object or body part of a person. If, for example, a comparatively strong decrease in the parameter is found, the beginning of the pinching of a hard object can be assumed. A very quick reaction to the start of the pinching process is then possible. When a softer object or body part of a person is pinched, the parameter changes by the same amount as in the case of a hard object only over a longer distance along the path, with the result that the limit value set for the hard pinching process would not be reached . The calculation of at least one further derivation based on a further route and the specification of a separate limit value provide a remedy here. It can thus be switched off as quickly as possible when a softer object is pinched.

With this evaluation it is also possible to selectively determine both the first and higher derivatives. Separate limit values are to be provided for the result of the first and / or higher derivations, with a switch-off or reversal of the direction of movement being initiated after only one limit value has been exceeded. The specification of different limit values for different derivations as well as the specification of a different limit value set for several determinations of the derivations running in parallel in relation to different paths result in a large number of limit values to be specified. An advantageous further development therefore provides for the summarization of the results from different derivations into a single limit value. The number of limit values to be specified thus corresponds to the number of several leads running in parallel in relation to the different paths. The summary can be done, for example, by adding the results of the different derivatives.

In general, higher derivatives are formed from the lower derivatives already determined. A further simplification of the method according to the invention sees the determination of higher derivatives, provided that this determination is provided, at each. learn the smallest way for which a lower derivative already -. - was averaged. If several leads are determined in parallel with respect to different paths, the higher leads can then be determined in one calculation step.

In an advantageous embodiment, an adaptive limit value determination is provided in the signal processing arrangement 11, in which the one or the different limit values is adaptively defined in the arrangement 11 on the basis of one or more test pinching processes. With this measure, manufacturing tolerances in the power-operated parts as well as different geometrical relationships for each individual part are taken into account by optimally defining the limit values.

In a further embodiment, the adjustment of the adjustment of the part into several partial areas is provided, each of which different limit values are assigned. The further refinement of the method and the device achieved thereby brings advantages in the detection of the beginning of the pinching, since different dimensions of body parts or objects can be reacted to at different speeds accordingly. Furthermore, this measure enables a very wide range of change in force or change in speed of the actuated part, it being possible to determine optimum limit values for the different ranges.

Any signal filtering provided in the signal processing arrangement 11 filters out higher-frequency interferences from the detected parameter, which can arise from mechanical effects on the part. If the device is installed in motor vehicles, such disturbances arise, for example, from a roadway with potholes. The possibility of incorrect detection, which is particularly given when determining higher derivatives, is thus reduced.

A further increase in operational safety is given by the specification of a minimum speed, below which a shutdown or a reversal of the direction of movement is triggered. An extremely low speed occurs, for example, when the part is difficult to drive. It may no longer be possible to derive a parameter along the way due to the slight change in the speed. With this measure, blocking of the drive or the part can already be detected at the beginning of the movement in the rest position of the part.

In an advantageous development of the method and the device according to the invention, a correction of the detected speed of an electric motor or transmission is provided as a function of the operating voltage. The determined speed is increased by one Number correction value increased or decreased, which, for example in a data memory of the signal processing arrangement 11 for the operating voltages to be taken into account in the correction, stores the functional relationship between speed and torque or a variable proportional to the torque as a function of the measured speed and the measured operating voltage for a given torque is determined. The speed-torque characteristic of the electric motor 10 is assumed to be known, its operating voltage being specified as a parameter. In the case of a direct current electric motor 10, it is therefore possible to correct the detected speed from the measured operating voltage, which is weighted with a constant determined from the functional relationship shown in FIG. 2, in a particularly simple manner. A change in the operating voltage leads to a parallel shift of the linear speed-torque characteristic. Furthermore, the speed depends linearly on the operating voltage with a fixed torque. For a given torque, it is possible to determine the constants at only two different speeds. The functional relationship between torque M and speed n can be seen in the data sheet of the electric motor used. The speed n can also be related to any intermediate stage within the drive.

If an electric motor is used as drive 10, the functional relationship between speed n and torque M shown in FIG. 2 is the starting point when determining the limit values. The maximum permissible pinching force corresponds to a load torque on the motor, which results in a speed decrease. The pinching force is thus dependent on the gradient of the speed-torque characteristic of the corresponding motor. The limit values can theoretically be derived. An experimental limit value determination is preferably provided. The adaptive limit value determination already described is particularly advantageous since the characteristic curve 16 between the individual motors can be subject to scattering. This would lead to an unacceptable fluctuation in the pinching forces. The adaptation is carried out on the fully assembled part. The part is subjected to defined load moments, from which the speed of the motor is determined.

The slope of the characteristic curve specific to this engine is determined from various measuring points. This measurement sequence can be carried out separately for each direction of rotation, for example, taking into account the self-heating of the motor during the measurement process. From the characteristic curves 16 determined, the limit values and the constant when correcting the detected speed as a function of the operating voltage are determined.

A Hall sensor, which preferably contains two Hall elements, is particularly suitable for detecting the speed of the drive 10. Direction of rotation can be determined with two elements. The Hall effect has proven to be particularly insensitive to interference and inexpensive to manufacture, especially in harsh environmental conditions.

Claims

Expectations

1. A method for operating power-operated parts in which there is a risk of objects or body parts being trapped, with the features:

- Detection of a parameter that has a relation to the actuating force;

- detection of the distance covered by the part;

- Determination of at least one derivation of the course of the parameter according to the route;

- comparison of the result of the derivation with a limit value;

- Switching off or reversing the direction of movement when the limit value is exceeded.

2. The method of claim 1, wherein the results of the first and / or higher derivative are summarized and compared with a limit value. - 1 -

3. The method according to claim 1, in which a plurality of derivatives are determined based on different distances traveled and the results are each compared with a limit value.

4. The method according to claim 3, in which the results of the first and / or higher derivatives are in each case summarized and compared with a limit value in each case.

5. The method according to any one of the preceding claims, in which the higher derivatives are determined from the lower derivatives, which are related to the smallest path.

6. The method according to any one of the preceding claims, in which the entire actuation path of the power-operated part is divided into several sub-areas, to which different limit values are assigned.

7. The method according to any one of the preceding claims, with signal filtering for high-frequency interference signals of the detected parameter in a signal processing arrangement (11).

8. The method according to any one of the preceding claims, with an adaptive limit value determination, in which the functional relationship between the parameter and the actuating force is determined experimentally by specifying at least two different pinching forces.

9. The method according to any one of the preceding claims, wherein the speed of a drive (10) is detected as a parameter of at least one sensor (13) and is forwarded to the signal processing arrangement (11).

10. The method according to claim 8, in which the path covered by the part is determined from the integration of the speed signal.

11. The method according to claim 8 or 9, in which a minimum speed is specified, below which a switch-off or reversal of the direction of movement is caused.

12. The method according to any one of the preceding claims, with an electric motor drive (10).

13. The method according to any one of claims 1 to 10, with a pneumatic or hydraulic drive (10).

14. The method according to claim 12, with a correction of the detected speed of the electric motor (10) in the signal processing arrangement (11), the determined speed (n) being increased or decreased by a speed correction value which results from the functional relationship between speed (n) and torque (M) or a variable proportional to the torque (M) as a function of the measured speed (n) and the measured operating voltage (U) for a given torque (M) is determined.

15. The method according to claim 12, with a correction of the detected speed of a direct current electric motor (10) in the signal processing arrangement (11), the determined speed (n) being increased or decreased by a speed correction value which results from the measured operating voltage (U) is determined and weighted with a constant which is derived from the functional relationship between speed (n) and torque (M) or a variable proportional to torque (M) with at least two different operating voltages (U) and given torque (M) is determined.

16. The method according to any one of claims 8 to 13, in which at least one Hall sensor is provided as the speed sensor.

17. Device for operating power-operated parts, in which there is a risk of objects or body parts being trapped, with the features:

- Detection of a parameter that has a relation to the actuating force;

- detection of the distance covered by the part;

- comparison of the result of the derivation with a limit value;

18. The apparatus of claim 17, with the determination of a plurality of derivatives based on different distances traveled and a comparison of the results in each case with a limit value.

19. Apparatus according to claim 17 or 18, in which the entire actuation path of the power-operated part is divided into several sub-areas, to which different limit values are assigned.

20. Device according to one of claims 17 to 19, with an adaptive limit value., In which the functional relationship between the parameter and the actuating force is given experimentally by specifying at least two different pinching forces.

21. Device according to one of claims 17 to 20, in which the speed of a drive 10 is detected as a parameter by at least one sensor (13) and is forwarded to the signal processing arrangement (11).

22. The device according to one of claims 17 to 21, with an electric motor drive (10).

23. The device according to one of claims 17 to 22, with a correction of the detected speed of a DC electric motor (10) in the signal processing arrangement (11), wherein the determined speed (n) is increased or decreased by a speed correction value that determined from the measured operating voltage (U) and weighted with a constant which is derived from the functional relationship between speed (n) and torque (M) or a variable proportional to the torque (M) with at least two different operating voltages (U) and given torque (M) is determined.