Trapping Prevention Guard and Method for Controlling a Motor-Driven Adjusting Device

• US 20090039814A1
• Filed: 02/15/2007
• Published: 02/12/2009
• Est. Priority Date: 02/17/2006
• Status: Active Grant

• Current Assignee: Brose Fahrzeugteile GmbH & Co. KG
• Original Assignee: Brose Fahrzeugteile GmbH & Company KG Coburg
• Inventors: Rosch, Thomas
• Granted Patent: US 7,786,689 B2
• Time in Patent Office: Days
• US Class Current: 318/434
• CPC Class Codes: H02H 3/006 Calibration or setting of parameters
• CPC Class Codes: H02H 7/0851 for motors actuating a movable member between two end positions, e.g. detecting an end position or obstruction by overload signal

Abstract

In order to reliably detect a jamming situation, in particular in a seat adjusting means, provision is made for a total loading exerted by the drive during a start phase to be determined and for this to be fixed as the basic loading. The existence or non-existence of a jamming situation is finally determined during a monitoring phase by comparing the gasinc loading and the total loading that varies during operation of the adjusting apparatus.

Claims

1. A trapping prevention guard for an adjusting device, the trapping prevention guard comprising

a motorized drive and

a control unit that is configured to derive a total load exerted by the motorized drive from at least one detected characteristic variable of the motorized drive in order to monitor for a trapping instance,

wherein the control unit is configured to derive an initial total load during a start phase at the beginning of an actuation operation of the adjusting device and to store the initial total load as the nominal load of the adjusting device, and

wherein the control unit is configured to determine whether trapping has occurred during a monitoring phase from a comparison between the nominal load and the total load which varies during the actuation operation of the adjusting device.

2. The trapping prevention guard according to claim 1, in which the start phase corresponds to a translatory adjustment path of up to 50 mm or an inclination adjustment of approximately 1°

of the adjusting device.

3. The trapping prevention guard according to claim 1, wherein the control unit employs a first mathematical model in order to determine the total load, and changes over to a second mathematical model that takes into account the trapping instance only if there is a significant deviation between the total load and the nominal load or if there is a significant deviation in the detected characteristic variable for assessing whether trapping has occurred.

4. The trapping prevention guard according to claim 3, wherein only the second model comprises a spring model which takes into account the trapping instance.

5. The trapping prevention guard according to claim 3, wherein, when a changeover is made to the second model, at least some of the variables previously determined with the first model are used as input variables for the second model.

6. The trapping prevention guard according to claim 3, wherein the significant deviation occurs as the result of

exceeding a limit value for the difference between the total load and nominal lead, or

exceeding a limit value for a derivative of the difference,

or both.

7. The trapping prevention guard according to claim 1, wherein the average value of the total load is used in order to determine the nominal load.

8. The trapping prevention guard according to claim 1, wherein the nominal load is also determined during the monitoring phase and stored as the current nominal load that is used for subsequent measurements of the characteristic variable during the monitoring phase for comparison with the total load.

9. The trapping prevention guard according to claim 8, wherein the current nominal load is determined from a plurality of measured values of the characteristic variable by calculating an average value.

10. The trapping prevention guard according to claim 3, wherein the nominal load is stored when the significant deviation occurs, and the further profile of the total load, represented as the difference between the current total load and the previously stored nominal load, is monitored for the presence of a trapping instance.

11. The trapping prevention guard according to claim 8, wherein, if the significant deviation can be attributed to a running difficulty or a load fluctuation, determination of the current nominal load is continued.

12. The trapping prevention guard according to claim 1, wherein the input variables of the motorized drive are used to determine the total torque of the motorized drive and, in the start phase, a nominal torque, to derive a trapping moment.

13. The trapping prevention guard according to claim 12, wherein the trapping moment is weighted with a weighting parameter that takes into account the mechanics of the adjusting device, in order to determine the resulting trapping force.

14. The trapping prevention guard according to claim 13, wherein, in order to determine the weighting parameter, the trapping prevention guard makes measurements on a physical model and stores the measurement in a table, from which table the association of the resulting trapping moment to the resulting trapping force can be made.

15. The trapping prevention guard according to claim 1, wherein a spring model for a trapping instance is used as a basis for assessing whether trapping has occurred.

16. The trapping prevention guard according to claim 15, wherein the trapping prevention guard is configured to determine the value of at least one spring constant and to use value of the spring constant to determine whether trapping has occurred.

17. The trapping prevention guard according to claim 16, wherein the the trapping prevention guard is configured to use the absolute value of the spring constants or their profile or both to decide whether trapping has occurred.

18. The trapping prevention guard according to claim 1, in which at least three load threshold values are defined and a value of the decision criterion is determined and evaluated between two load threshold values in each case.

19. The trapping prevention guard according to claim 1, wherein the motorized drive is a rotation speed-controlled DC motor.

20. A trapping prevention guard for an adjusting device, the trapping prevention guard comprising

a motorized drive and

a control unit configured to determine a characteristic variable of the motorized drive and to evaluate the characteristic variable using a first mathematical model in order to monitor for a trapping instance, and

wherein the control unit is configured to changeover to a second mathematical model that takes into account the trapping instance if there is a significant deviation in the characteristic variable for assessing whether trapping has occurred.

21. A method for controlling a motor-driven adjusting device, the method comprising

deriving a total load exerted by the drive from at least one detected characteristic variable of the motorized drive in order to monitor for a trapping instance,

wherein the total load is first derived during a start phase in each case at the beginning of an actuation operation of the adjusting device and stored as the nominal load of the adjusting device, and

determining whether trapping has occurred during a monitoring phase from a comparison between the nominal load and the total load which varies during the actuation operation of the adjusting device.

22. A trapping prevention guard for an adjusting device, the trapping prevention guard comprising

a motorized drive and

a control unit that is configured to derive a total load exerted by the motorized drive from at least one detected characteristic variable of the motorized drive in order to monitor for a trapping instance,

wherein the control unit is configured to determine whether trapping has occurred during a monitoring phase from a comparison between a nominal load and a total load which varies during the actuation operation of the adjusting device.