Method and arrangement for ensuring road tracking up to a predefined lateral acceleration limit using a pid controller in a vehicle

An arrangement for ensuring road tracking up to a predefined lateral acceleration limit in a vehicle having an autonomous steering function arranged to selectively apply a steering wheel overlay torque to a normal steering assistance torque in an electrical power assisted steering system of the vehicle, the arrangement further comprising:

• a closed loop controller having a comparator for comparing a predetermined lateral acceleration limit with an acquired current lateral acceleration signal of the vehicle to obtain a controller error;
• a lateral acceleration limiter arranged to set a torque limit for the steering wheel overlay torque, if the controller error is equal to or greater than a predetermined first threshold, to the actual value of the steering wheel overlay torque as an initial value for the torque limit;
• and
• a proportional-integral-derivative (PID) controller arranged to receive the controller error and provide the torque limit for the steering wheel overlay torque after setting the torque limit to the initial value.

A vehicle comprising an arrangement for ensuring road tracking up to a predefined lateral acceleration limit in a vehicle having an autonomous steering function arranged to selectively apply a steering wheel overlay torque to a normal steering assistance torque in an electrical power assisted steering system of the vehicle, the arrangement further comprising:

• a closed loop controller having a comparator for comparing a predetermined lateral acceleration limit with an acquired current lateral acceleration signal of the vehicle to obtain a controller error;
• a lateral acceleration limiter arranged to set a torque limit for the steering wheel overlay torque, if the controller error is equal to or greater than a predetermined first threshold, to the actual value of the steering wheel overlay torque as an initial value for the torque limit;
• and
• a proportional-integral-derivative (PID) controller arranged to receive the controller error and provide the torque limit for the steering wheel overlay torque after setting the torque limit to the initial value.