Electric brake system
Provided is an electric brake system that changes responsiveness depending on responsiveness required for an electric brake device, thereby enabling operation sound and power consumption to be reduced without influencing movement of a vehicle. The electric brake system includes one or more electric brake device ( 3 ) each having a control operation module ( 12 ) for performing follow-up control for a target braking force. The electric brake system includes a response requirement determination module ( 14 ) for determining responsiveness required for the brake actuator ( 4 ) from one or both of a braking requirement and the vehicle travelling condition. The braking requirement is outputted from a brake operation member or a vehicle-stable-travelling control system. The electric brake system includes a control modification module ( 15 ) for changing a control operation formula to be used for follow-up control by the module ( 12 ), depending on responsiveness determined by the module ( 14 ).
1. An electric brake system including one or more electric brake device, each electric brake device includes:
a brake actuator mounted on a vehicle, the brake actuator having a brake rotor, a friction member, a friction member actuator configured to press the friction member to the brake rotor, and an electric motor configured to drive the friction member actuator; and
a control operation module configured to perform follow-up control so that a braking force generated by the brake actuator follows a target braking force by controlling the electric motor,
the electric brake system comprising:
a response requirement determination module configured to determine responsiveness required for the brake actuator, by applying a predetermined rule, from one or both of a braking requirement and information about a travelling condition of the vehicle, the braking requirement being outputted from a brake operation member which is manipulated by a vehicle operator or from a vehicle-stable-travelling control system for generating the braking force to cause the vehicle to travel stably; and
a control modification module configured to change a control operation formula to be used for the follow-up control by the control operation module, depending on the responsiveness determined by the response requirement determination module.
2. The electric brake system as claimed in claim 1 , wherein
the response requirement determination module determines the responsiveness from the target braking force or a control target value obtained from the target braking force.
3. The electric brake system as claimed in claim 1 , wherein
the response requirement determination module estimates responses of the brake actuator, each response being obtained when a corresponding one of a plurality of control operation formulas is applied, the control modification module allowing switchover among the plurality of control operation formulas, compares the plurality of estimation results with each other, and determines the responsiveness on the basis of the estimation comparison results.
4. The electric brake system as claimed in claim 1 , wherein
the response requirement determination module determines the responsiveness from at least one of a speed of the vehicle on which the electric brake device is mounted, and a wheel speed thereof.
5. The electric brake system as claimed in claim 1 , further comprising a wheel speed control device configured to control a wheel speed with use of a braking force without depending on the vehicle operator's manipulation to the brake operation member of the vehicle to which the electric brake system is provided, wherein
in a state in which the control by the wheel speed control device is being executed, the response requirement determination module selects a predetermined control operation formula that achieves fast responsiveness as the control operation formula.
6. The electric brake system as claimed in claim 4 , wherein
when the speed of the vehicle to which the electric brake system is provided is equal to or smaller than a predetermined value, the response requirement determination module selects a predetermined control operation formula that achieves slow responsiveness as the control operation formula.