Fault monitoring for a complex computing unit

1. A control device for a vehicle with an internal fault monitoring circuit, the control device comprising:

a safe computing unit executing a first monitoring function for monitoring the safe computing unit and a second monitoring function for monitoring the first monitoring function; and

an unsafe computing unit executing a third monitoring function;

wherein the second monitoring function includes changing the operation of the first monitoring function of the safe computing unit to induce faults in the third monitoring function; and

the third monitoring function detects the induced faults in the operation of the first monitoring function and reports the induced faults to the second monitoring function.

2. The control device as claimed in claim 1 , wherein a fault exists if:

the operation of the second monitoring function does not induce faults in the third monitoring function in the defined manner, or

the third monitoring function does not report the induced faults to the second monitoring function in the defined manner.

3. The control device as claimed in claim 1 , wherein the third monitoring function detects, in the event of a fault in the safe computing unit, said fault.

4. The control device as claimed in claim 1 , wherein the second monitoring function includes, in the event of a fault in the unsafe computing unit, detecting said fault.

5. The control device as claimed in claim 1 , wherein the fault monitoring circuit changes the safe computing unit to a safe state in the event of a reported fault in the safe computing unit.

6. The control device as claimed in claim 1 , wherein the fault monitoring circuit resets the safe computing unit in the event of a reported fault.

7. A vehicle comprising:

a controller monitoring and controlling operation of the vehicle;

an internal fault monitoring circuit;

a safe computing unit executing a first monitoring function for monitoring the safe computing unit and a second monitoring function for monitoring the first monitoring function; and

an unsafe computing unit executing a third monitoring function;

wherein the second monitoring function includes changing the operation of the first monitoring function of the safe computing unit to induce faults in the third monitoring function; and

the third monitoring function detects the induced faults in the operation of the first monitoring function and reports the induced faults to the second monitoring function.

8. A method for monitoring faults in a control device with two computing units, wherein a first computing unit comprises a safe computing unit and a second computing unit comprises an unsafe computing unit, the method comprising:

specifically changing operation of a first monitoring function of the safe computing unit using a second monitoring function of the safe computing unit in order to induce a fault in a third monitoring function of the unsafe computing unit;

operating the third monitoring function of the unsafe computing unit using the second monitoring function, including the specifically changed contents;

monitoring the safe computing unit with the third monitoring function and detecting faults;

reporting the detected induced faults to the second monitoring function from the third monitoring function; and

establishing a safe state of the safe computing unit if a non-induced fault is detected by the third monitoring function or if the induced fault is not detected by the third monitoring function.