Electricity: motive power systems – Automatic and/or with time-delay means – Movement – position – or limit-of-travel
Reexamination Certificate
2002-03-04
2003-10-07
Ro, Bentsu (Department: 2837)
Electricity: motive power systems
Automatic and/or with time-delay means
Movement, position, or limit-of-travel
C318S468000, C318S282000, C318S286000, C318S266000, C318S268000, C049S026000, C049S028000
Reexamination Certificate
active
06630808
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a method for electronically monitoring and controlling a process for adjusting movable parts, in particular windows and tilt/slide sunroofs of a motor vehicle, to ensure protection against pinching.
2. Description of the Related Art
The methods for realizing protection against pinching known to date can be roughly classified into direct and indirect methods.
In the direct methods, the pinching force is measured explicitly using appropriately-placed sensors. When a specified threshold value is exceeded, the drive is stopped or reversed. “Sensor strips” that are integrated in the seals of the stop are often used in these methods. The disadvantage of direct methods lies in the high instrument-related expenditure and the relatively poor reliability and resistance to ageing processes.
The current indirect methods are based on the evaluation of other measured quantities that are associated with the force. Such measured quantities are typically the current flowing through the drive, the drive speed of the moved part, or the speed of a rotating part of the drive.
The indirect methods make use of the fact that the measured quantities associated with the force also change when pinching occurs and are therefore suited to early detection of the pinching state. They also involve a high technical expenditure, however, and are basically susceptible to changing external influences. Vehicle movements, temperature and weather fluctuations, or ageing processes, for example, must also be taken into account.
Although reliability can be increased using a combination of both methods, this also causes the technical expenditure to increase even further.
SUMMARY OF THE INVENTION
The method according to the invention for electronically monitoring and controlling a process for adjusting movable parts having the features of the primary claim has the advantage that considerably greater reliability as well as a much higher sensitivity and speed is achieved with a lower technical expenditure.
The method is based on a completely new approach which is based on a physical description of the adjustment procedure. This description takes place based on a model that reflects—either completely or at least essential parts of—the adjustment procedure and is stored in a detection device. Using this model, typical process variables are found and optimized with consideration for measured input and output variables that are characteristic for the process. The process variables can be found on an analytical or iterative basis, for example.
By evaluating the typical process variables by means of comparison with process variables stored in the detection device, a deviation of the course of the process from normal behavior can not only be recognized unequivocally and with maximum sensitivity, it can also be interpreted in differentiated fashion.
Depending on the evaluation, a particular correcting quantity for the process is determined that is fed to the process and influences it. For example, if the process variables signal that a human hand is being pinched in a window or tilt/lift sunroof closing procedure, the correcting quantity will then influence the process in such a way that the electronic drive is reversed or stopped, for example. It is also conceivable that, when a partial sluggishness is detected, the process is influenced so that current flowing to the motor is temporarily increased.
The method described in claim 1 for finding and optimizing certain process variables represents a particular method for the real-time evaluation of a measured course of a value. This real-time evaluation ensures immediate access to variables that cannot be measured directly that are extremely relevant for monitoring the procedure and that contain important information.
Advantageous further developments of the method according to the primary claim are possible by means of the measures indicated in the subclaims.
It is advantageous, for example, if the model describing the process and stored in the detection device depicts the mechanical or hydraulic/pneumatic processes, because this is necessary in order to monitor the adjustment procedure.
It is furthermore advantageous if the model contains the Newtonian equation in the general, vectorial form
m·{umlaut over ({overscore (x)})}={overscore (F)}
In this equation, m is a mass, such as the mass of the movable part, and F is the sum of acting forces, for example, the forces that act on the movable part. The quantity F can be dependent on various parameters, such as state variables such as the location x or one of the derivatives with respect to time of x, and on particular damping and friction parameters.
In a more particular form, the equation can take on the form:
m·{umlaut over ({overscore (x)})}={overscore (C)}·I+d·{dot over ({overscore (x)})}+c·{overscore (x)}+{overscore (F)}
d
+m·{overscore (g)}
This equation describes a movement of a movable part that can be subject to a damping d, a spring stiffness c=c(t), a driving force F
D
=C·I, and a disturbing force F
d
.
Of primary importance to the method according to the invention is not to solve the differential equation shown above, that is, to find the function x(t), but rather to find and optimize process variables in a first method variant that are relevant to the detection of the pinching process and its differentiated interpretation, i.e., the parameter c and d, in particular, or variables dependent thereon.
In a further variant of the method, instead of the parameters c and d, at least one output variable is calculated with consideration for the structure of the type of differential equation shown hereinabove and compared with the appropriate measured output variables.
In parallel with the real procedure, therefore, a simulation takes place that also makes it possible to reliably detect a deviation from the normal case and, in particular, a pinching process.
Both method variants are described in greater detail hereinafter.
The differential equation of the model stored in the detection device is not limited to a particular form; the only important thing is that it can be used to describe the mechanical or hydraulic/pneumatic processes. It can also take further disturbance variables into account, for example, or be transformed into the frequency response range, for instance, in alternative representations. It is also feasible that the model depicting the various processes is only composed of data fields from which the optimal typical process variables can be taken and compared with the calculated process variables.
A further advantage arises when a differential equation is included in the model for describing the adjustment procedure or the opening and closing procedure that describes the current build-up in the electronic drive.
An equation of this type for the driving force F
D
having the general form
F
D
=f
(
E,I
)
provides a relationship between the mechanical and electric variables for describing the adjustment process.
A possible differential equation for permanent-magnet d.c. motors has the general form
{overscore (C)}·{dot over ({overscore (x)})}
=−(
L·{dot over (I)}
)+
E+R·I
Using the equation shown hereinabove for current build-up, the aforementioned relationship between the mechanical variables of the motion equation and the electric variables, that is, the current I flowing through the electronic drive, the electrical voltage E at the drive, and the electrical resistance R of the drive, can be created.
The voltage E at the electronic drive can therefore be used in advantageous fashion as input variable for the method according to the invention.
The following are suited as the output variables fed to the detection device: the current I flowing through the electronic drive and/or the position x of the movable part and/or an angular position &phgr; of a rotating part of the electronic drive proportional to position x and/or one of the derivatives with respect t
Kliffken Markus
Krueger Hartmut
Wolf Joerg
Duda Rina I.
Ro Bentsu
Robert & Bosch GmbH
Striker Michael J.
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