Method for controlling an ABS function in a hydraulic braking system of a cycle or motorcycle, in particular of a bicycle, wherein there is provided:
- an inlet, to be hydraulically connected to a master cylinder associated with a brake lever,
- an outlet, to be hydraulically connected to an actuator cylinder associated with a brake device, intended to be associated with a wheel of the vehicle,
- a fluid accumulator having an accumulation chamber defined by a movable member within a cavity, said movable member being normally in a starting position corresponding to a minimum volume of the accumulation chamber,
- an electrically actuated valve unit, switchable between:
- a first operating condition, in which said inlet and said outlet communicate with each other and said accumulation chamber of the fluid accumulator is isolated, and
- a second operating condition in which the communication between said inlet and said outlet is interrupted and the accumulation chamber of said fluid accumulator is in communication with said outlet,
- said method comprising the operation of detecting, by means of an electronic controller, a condition in which activation of an ABS function is required and of causing, in said condition, a switching of said valve unit from the first operating condition to the second operating condition, also enabling a movement of the movable member of the fluid accumulator in a direction corresponding to an increase in the volume of the accumulation chamber, so as to cause a decrease in pressure in the connection line between said outlet and the actuator cylinder of the brake device,
- the method comprises controlling, by means of said electronic controller, the position of the movable member of the fluid accumulator, both during an activation of the ABS function and during a deactivation of the ABS function, so as to cause a non-abrupt, but progressive, variation of the pressure in the line connecting to the actuator cylinder of the brake device, both during an activation of the ABS function and during a deactivation of the ABS function,
- said progressive pressure variation being determined, by means of said electronic controller, as a function of:
- a first parameter, which is the rotational speed of said wheel to which the brake device is associated, detected or calculated based on a signal emitted by a sensor intended to be associated with the wheel, and also as a function of:
- a second parameter, which is:
- the pressure in the actuator cylinder associated with the brake device,
- or the deceleration of the vehicle detected or calculated based on a sensor intended to be associated with the vehicle.