Method for detecting a resistance on a brake pedal pulled by an actuator and method for controlling an actuator

A method for controlling an actuator of a brake system of a motor vehicle during an operation of the actuator triggered by a driver-independent brake request, the method comprising:

• measuring a position or travel of an actuating element of the actuator during the movement of the brake pedal;
• measuring a position of the brake pedal or an input piston coupled to the brake pedal during the movement of the brake pedal;
• calculating a position dependent force component acting upon the brake pedal based on the measured position or travel of the actuating element and the measured position of the brake pedal or the input piston coupled to the brake pedal, the position dependent force component defining a tensile force operating on the brake pedal, wherein the tensile force is below a predefined threshold in the absence of the resistance on the movement of the brake pedal;
• measuring a relative speed between the movement of the actuating element and the movement of the brake pedal or the input piston coupled to the brake pedal;
• calculating a speed dependent force component acting upon the brake pedal based on the measured relative speed between the movement of the actuating element and the movement of the brake pedal or the input piston coupled to the brake pedal, the speed dependent force component corresponding to a change in acceleration of the movement of the brake pedal in the presence of the resistance on the movement of the brake pedal;
• calculating a total force acting upon the brake pedal based on the calculated position dependent force and the calculated speed dependent force during a time period when the brake pedal is pulled by the actuator in response to the brake request from the driver independent brake system;
• detecting the resistance on the movement of the brake pedal during an operation of the actuator in response to the total force exceeding a predefined threshold;
• and
• preventing the movement of the brake pedal or the input piston coupled to the brake pedal when the resistance on the brake pedal pulled by the actuator is detected.

A non-transitory computer readable storage medium that stores processor executable program code to implement a method for detecting a resistance on a movement of a brake pedal of a brake system when the brake pedal is pulled by an actuator in response to a brake request from a driver independent brake system, the method comprising:

• measuring a position or travel of an actuating element of the actuator during the movement of the brake pedal;
• measuring a position of the brake pedal or an input piston coupled to the brake pedal during the movement of the brake pedal;
• calculating a position dependent force component acting upon the brake pedal based on the measured position or travel of the actuating element and the measured position of the brake pedal or the input piston coupled to the brake pedal, the position dependent force component defining a tensile force operating on the brake pedal, wherein the tensile force is below a predefined threshold in the absence of the resistance on the movement of the brake pedal;
• measuring a relative speed between the movement of the actuating element and the movement of the brake pedal or the input piston coupled to the brake pedal;
• calculating a speed dependent force component acting upon the brake pedal based on the measured relative speed between the movement of the actuating element and the movement of the brake pedal or the input piston coupled to the brake pedal, the speed dependent force component corresponding to a change in acceleration of the movement of the brake pedal in the presence of the resistance on the movement of the brake pedal;
• calculating a total force acting upon the brake pedal based on the calculated position dependent force and the calculated speed dependent force during a time period when the brake pedal is pulled by the actuator in response to the brake request from the driver independent brake system;
• and
• detecting the resistance on the movement of the brake pedal during an operation of the actuator in response to the total force exceeding a predefined threshold.