Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle diagnosis or maintenance indication
Reexamination Certificate
2000-09-14
2001-09-25
Camby, Richard M. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle diagnosis or maintenance indication
C701S039000, C701S043000, C701S076000
Reexamination Certificate
active
06295490
ABSTRACT:
BACKGROUND OF THE INVENTION
Electronic control systems are increasingly utilized in vehicles. These control systems operate at least one actuator element of a vehicle on the basis of detected operating variables or on the basis of operating quantities derived from measured quantities. Such control systems are used to control the drive unit, the brake system or other functions. For example, in the context of so-called drive-by-wire systems or brake-by-wire systems, an actuator of the vehicle is driven or actuated on the basis of the detected driver command via an electronic control system. What is common to these control systems is that the detection of an operating quantity, which influences the basic function, is redundantly secured. Accordingly, in these systems, the position of the operator-controlled element (accelerator pedal, brake pedal), which is actuated by the driver, is detected by at least two measuring devices independently of each other. The same applies to systems (for the actual value detection) wherein the actuator is adjusted in the context of a control loop (for example, a positioning control) in accordance with a desired value derived from the driver command. The detection of the particular operating quantity is at least redundant and serves for fault detection, for example, in that the two detected measured quantities or the quantities derived therefrom are checked with respect to each other as to a pregiven tolerance range. A procedure of this kind is disclosed with respect to the example of a drive-by-wire system in U.S. Pat. No. 5,170,769.
In checks of this kind, an actual fault condition with subsequent emergency operation with a view to disturbance signals is only detected when the check has shown the result “implausible” over a specific time. The emergency function is therefore initiated relatively late. In this way, damage in the actuator can occur with this actuator being actuated as in normal operation notwithstanding a fault condition. This is primarily the case for the control of a throttle flap by means of an actuating motor where, for example, a dynamic driving to the mechanical stop with mechanical damage as the consequence can occur when, for example, there is a separation of the signal line.
U.S. Pat. No. 5,119,300 discloses sensors which output a base signal (for example, zero) in an operating state of a vehicle as well as in the case of a fault. With the occurrence of the base signal, a preliminary emergency function is initiated and thereafter a fault check is carried out. The emergency function, which is provided for the case of a fault, is only initiated when the fault condition has been determined.
SUMMARY OF THE INVENTION
It is an object of the invention to provide measures which shorten the reaction time in response to an implausibility situation without the availability of use of the control system being significantly affected for the case wherein no fault condition is present.
The method of the invention is for operating an actuator in a vehicle and includes the steps of: detecting a first operating quantity; actuating the actuator in dependence upon at least the first operating quantity; doing one of the following: detecting the first operating quantity redundantly or detecting a second operating quantity having a clear relationship to the first operating quantity; comparing the first operating quantity to the redundantly detected first operating quantity or to the second operating quantity in the context of a plausibility check; for implausibility, initiating a first fault reaction operation; and, for a continued presence of the implausibility, initiating a second fault reaction operation.
Another embodiment of the method of the invention for operating an actuator in a vehicle includes the steps of: detecting an operating quantity; actuating the actuator in dependence upon at least the operating quantity; detecting a fault condition from a plausibility check of the operating quantity; for implausibility, immediately initiating a first fault reaction operation wherein at least one of the velocity of the actuator and the acceleration of the actuator is limited; and, for a continued presence of the implausibility, initiating a second fault reaction operation wherein the actuation of the actuator is brought to standstill or a substitute operating quantity is applied to actuate the actuator.
A rapid reaction (first fault reaction operation) is initiated immediately after the occurrence of an implausibility in the area of the detection of operating quantities in that a first reaction to an implausibility between two operating quantity signals is initiated immediately after occurrence of the first implausibility with the operating quantity signals having a clear relationship to each other. In this way, a significant reduction of the availability of use of the control system is avoided because damaging effects of the implausibility are substantially avoided because of the first reaction without the availability of use being significantly limited. A second reaction defines an emergency operation of the control system. Because of this second reaction (second fault reaction operation), the system is lead into a safe condition after the elapse of a specific time with certain implausibility.
The application of this procedure is especially advantageous in so-called drive-by-wire systems wherein a power adjusting element is adjusted in dependence upon the driver command by means of a control loop. There, fault functions are recognized because of plausibility comparisons of the redundantly detected actual quantities and/or the redundantly detected desired quantity and a reaction takes place in correspondence to the above procedure. Because of the first reaction, the actuator is no longer driven dynamically to its mechanical end stops. This is done, for example, by limiting the adjusting speed of the actuator by limiting the current and/or the drive signal for the actuator. Mechanical damage is avoided. The second reaction to implausibility is then an emergency operation reaction via which the control is brought to standstill or driven further on the basis of substitute quantities.
Especially advantageous is the application to a position control wherein the desired value and the actual value represent the position of the power adjusting element. This takes place even when the actual value and/or the desired value is not redundantly detected and are instead checked by means of an operating quantity which has a clear relationship to the position (for example, the air mass). The two different quantities are converted to a common basis and the plausibility check is carried out on this basis.
Likewise advantageous is the application of the above procedure in brake-by-wire systems. Here too, at least the detection of the driver braking command takes place by means of at least a redundant determination of the degree of actuation of the brake pedal. Here too, a plausibility comparison of the signals is carried out for fault detection. In an advantageous manner, a first reaction is undertaken immediately after detecting the first implausibility. The first reaction is, for example, a brake control on the basis of the maximum value. After ensuring the fault detection, an emergency operation measure (for example, speed limiting) is initiated as the second reaction.
REFERENCES:
patent: 5119300 (1992-06-01), Bartke et al.
patent: 5170769 (1992-12-01), Berger et al.
patent: 5732371 (1998-03-01), Fujita
patent: 6049746 (2000-04-01), Southward et al.
patent: 6144904 (2000-11-01), Tseng
patent: 40-1135913 (1992-05-01), None
Camby Richard M.
Ottesen Walter
Robert Bosch
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