Device for adjusting the clamping force of an electromechanical brake
AssigneesHitachi Astemo France, Hitachi Astemo Heilbronn GmbH
InventorsJulien Sasso, Maxime Demandre, Weiqiao Wang, Alex Patrao Carqueijo
Life of this patent
Estimating the term…
Abstract
The clamping strategy of an electromechanical brake depends on an already existing hydraulic pressure, in order to adjust the mechanical component of the clamping force and avoid an excessive clamping of the brake. The hydraulic component (FHyd) of the clamping force is estimated according to a pressure measurement, subtracted from a target force (FTar) to obtain the mechanical component to be applied (FTarNew), and the electric motor for controlling clamping of the brake is stopped at a threshold value (I2) of the current that is supplied thereto, according to the value of this mechanical component to be applied.
Claims12
A motor control unit configured to control an electric motor of an actuator of an electromechanical parking brake when parking braking a wheel of a motor vehicle, comprising:
- a module for supplying commands to the electric motor, including brake clamping commands;
- a module for continuous measurements of values of an electric current supplied to the electric motor during the brake clamping commands;
- a module for measuring a hydraulic pressure in a braking hydraulic circuit;
- and
- a decision module, designed to control the command supply module according to predefined strategies, the strategies comprising, for the brake clamping commands, stopping the clamping at a target clamping force applied by the electromechanical parking brake, the stopping being decided by the decision module according to the measurements of the values of the electric current and according to a measured hydraulic pressure,
- wherein the decision module is adapted to estimate a total clamping force applied to the electromechanical parking brake by adding an electromechanical component depending on the values of the electric current and a hydraulic component depending on an estimate of a hydraulic pressure applied to the electromechanical parking brake and resulting from a previous service braking of the wheel, based on a hydraulic pressure measurement provided by said module for measuring a hydraulic pressure, and
- wherein the decision module is adapted to estimate the hydraulic component, then estimate a value of the electromechanical component for which the total clamping force will be equal to the target clamping force, and then control the command supply module to stop the clamping when a threshold of the electric current, estimated as corresponding to said value of the electromechanical component, is measured.
Dependencies are inferred from the claim text.