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In parameter LKA system state, actually what is "System is actuating" value mean?

jani12

Member
Protocol: J1939
Parameter Group: Active Steering Systems Controls 1 (ASSC1)
Parameter Group Number (PGN): 0xF13D
Parameter: Lane keeping assist (LKA) system state
Suspect Parameter Number (SPN): 9756

This parameter indicates the current state of the LKA feature. It's a 4-bit parameter. It has 16 states. One of the states is as follows:
0101b = System is actuating
What does this state mean?

The application is commercial truck.
The LKA feature is in the camera ECU. If the vehicle gets close to the lane marking, camera transmits torque demand message to the steering ECU to steer vehicle to center of the lane.

When does camera ECU broadcast "System is actuating" state? Does it broadcast this state when steering ECU applies torque to bring vehicle back to center of lane? Does steering ECU need to listen to this state? If yes, how should steering ECU use this state?

Is this a feedback to steering ECU? Camera is saying to steering ECU, I demanded torque and you are applying torque or actuating the system?
 

Diver300

Well-Known Member
Most Helpful Member
What are all the other states?

Without more context it's difficult to know what that particular state means, and even if you know that, it may not be clear how it's used.

My guess would be that "System is actuating" means that it is getting ready to work. I would expect that state to only be present for a short time after the system turns on.
 

jani12

Member
Some of the other states are system is not ready, temporarily not available, deactivated by the driver, ready (no warnings active), error, not available, LKA suppressed by operator behavior (like turn signal).

>> "System is actuating" means that it is getting ready to work
Shouldn't "getting ready to work" be "system is ready" state?
 

Diver300

Well-Known Member
Most Helpful Member
Some of the other states are system is not ready, temporarily not available, deactivated by the driver, ready (no warnings active), error, not available, LKA suppressed by operator behavior (like turn signal).

>> "System is actuating" means that it is getting ready to work
Shouldn't "getting ready to work" be "system is ready" state?
I really don't know. I would have expected there to be some state that says the system is in the process of initiating and should be ready soon, however that might well be "not ready". It could be that "System is actuating" may mean that a warning is being shown to the driver, or that a steering force is being asked for by the system.

In the end all the states are just names. The engineers who design the system agree on a set of behaviours that depend on a number of states, and often give those states names. The subtlety behind those states may be far more complicated than can be described in a few words.

The databases for CAN signals are often limited to quite short names for states. There may also be a load of comments that describe in detail what the signals mean, but those will probably be in separate documents, and not in the database.

For example, a lot of cars have a signal called "Power Mode", with states of "Key out", "Aux", "Ignition on", "Engine running" and "Crank". Maybe 20 years ago, those meant what they said. Nowadays they don't. There is no key to take out. A car can have the engine running to get the cabin hot or cold ready for the driver, but the Power Mode says that the state is "Key out". When the engine stops to save fuel at traffic lights, the Power Mode is still "Engine running", so that the instruments still work. When the lights change and the driver accelerates, the Power Mode doesn't go to "Crank", even though the starter motor operates, because in "Crank" mode, the radio might turn off.

Electric cars still emulate all those modes, even though there is no physical difference between any of them until the car is put into gear and the brake released.
 

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