Electric brake device
Provided is an electric brake device of which braking control accuracy is improved as a result of hysteresis in a load sensor being appropriately compensated for. The electric brake device includes: a direct load estimator configured to estimate a brake pressing force, using an output of the load sensor; an indirect load estimator configured to estimate a brake pressing force without using the output of the load sensor; and a hysteresis interpolator. When switching is performed between pressure increase and pressure decrease which causes hysteresis in the load sensor, the hysteresis interpolator performs control by use of the load estimated by the indirect load estimator without using the load sensor, in a predetermined range after the switching has been performed.
1. An electric brake device comprising:
an electric brake actuator and an electric brake control device,
the electric brake actuator including
a brake rotor,
a friction member to be brought into contact with the brake rotor,
an electric motor,
a friction member operator configured to bring the friction member and the brake rotor into contact with each other by the electric motor, and
a load sensor configured to detect a value that corresponds to a pressing force generated at a contact face between the friction member and the brake rotor by the friction member operator,
the electric brake control device including
a main controller configured to perform follow-up control on the pressing force at the contact face between the friction member and the brake rotor, in accordance with a command value provided from a brake operator, wherein
the electric brake control device includes
a direct load estimator configured to estimate the pressing force, using an output of the load sensor,
an indirect load estimator configured to estimate the pressing force without using the output of the load sensor, and
a hysteresis interpolator,
the direct load estimator includes
a first-estimation-correlation-using estimation unit configured to estimate the pressing force on the basis of a first estimation correlation, which is a correlation between a pressure increase amount of the pressing force and an output change of the load sensor, and
a second-estimation-correlation-using estimation unit configured to estimate the pressing force on the basis of a second estimation correlation, which is a correlation between a pressure decrease amount of the pressing force and an output change of the load sensor,
the hysteresis interpolator includes a pressure increase/decrease switching determination unit and a control switching unit,
the pressure increase/decrease switching determination unit performs determination as to switching from a pressure increase operation to a pressure decrease operation, for the pressing force, and determination as to switching from a pressure decrease operation to a pressure increase operation, for the pressing force, and
when the main controller performs load follow-up control based on the pressing force estimated by the first or second-estimation-correlation-using estimation unit and outputted by the direct load estimator, the control switching unit causes the main controller to perform follow-up control based on the indirect load estimator, in a state until a drive amount of the electric brake actuator reaches a predetermined amount after the switching between the pressure increase operation and the pressure decrease operation in line with a determination result by the pressure increase/decrease switching determination unit has been performed, and the control switching unit causes the main controller to perform, in a state after the drive amount of the electric brake actuator has exceeded the predetermined amount, load follow-up control based on the pressing force estimated by the first or second-estimation-correlation-using estimation unit of a correlation type different from that used before the switching between the pressure increase operation and the pressure decrease operation has been performed.
2. The electric brake device as claimed in claim 1 , comprising
an angle estimator configured to estimate an angle of the electric motor, wherein
the indirect load estimator estimates the pressing force on the basis of a correlation between the pressing force and the angle of the electric motor estimated by the angle estimator.
3. The electric brake device as claimed in claim 1 , comprising
a current estimator configured to estimate a current of the electric motor, wherein
the indirect load estimator estimates the pressing force on the basis of a correlation between the pressing force and the current of the electric motor.
4. The electric brake device as claimed in claim 1 , comprising
an angle estimator configured to estimate an angle of the electric motor, wherein
by use of the angle estimated by the angle estimator, the pressure increase/decrease switching determination unit determines switching between a pressure increase operation and a pressure decrease operation in a situation where a changing direction of the angle of the electric motor is reversed.
5. The electric brake device as claimed in claim 1 , comprising
an angle estimator configured to estimate an angle of the electric motor, wherein
on the basis of a change amount of the angle of the electric motor, the control switching unit performs determination as to a drive amount of the electric brake actuator at a time of performing switching from the indirect load estimator to the direct load estimator.
6. The electric brake device as claimed in claim 1 , wherein
on the basis of a change amount of the output of the load sensor, the control switching unit performs determination as to a drive amount of the electric brake actuator at a time of performing switching from the indirect load estimator to the direct load estimator.
7. The electric brake device as claimed in claim 1 , wherein
the electric brake actuator performs braking of a wheel of an automobile.