| CPC B62D 5/0487 (2013.01) [B62D 5/046 (2013.01); B62D 6/00 (2013.01)] | 9 Claims |
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1. A motor drive system in a steer-by-wire system in which a steering mechanism and a turning mechanism of a vehicle are mechanically separated, comprising:
a reaction force actuator configured to function as a motor that outputs a reaction force torque according to a driver's steering torque and a road surface reaction force; and
a turning actuator configured to function as a motor that outputs a turning torque for turning wheels, wherein
each of the reaction force actuator and the turning actuator has two control calculation units provided redundantly that perform a calculation related to a motor drive control, and two motor drive units provided redundantly that drive and output a torque based on a drive signal generated by a corresponding control calculation unit,
when the two sets of control calculation units and motor drive units corresponding to each other in each actuator are defined as a first system and a second system, respectively, and the other system viewed from one system is defined as a back system,
the control calculation units of the back system in each actuator operate by a collaborative drive mode in which the torque is output to the motor drive unit by using an information transmitted and received mutually by a communication between the systems in common,
in the reaction force actuator and the turning actuator, cooperative control calculation units, which are control calculation units of the systems paired with each other, operate in cooperation with each other based on an information transmitted and received mutually by a communication between the actuators,
when, of four control calculation units of the two systems for each actuator, one of the control calculation units of interest is defined as a focus control calculation unit,
the communication between the systems between the focus control calculation unit and the control calculation unit of the back system of the focus control calculation unit is defined as a communication between the adjacent systems, and
the communication between the actuators between the focus control calculation unit and the cooperative control calculation unit of the focus control calculation unit is defined to as a communication between the adjacent actuators,
the communication between the adjacent systems and the communication between the adjacent actuators are restored, when the focus control calculation unit is restored, after the focus control calculation unit is stopped during operation and at least one of the communication between the adjacent systems or the communication between the adjacent actuators is interrupted,
wherein
each of the control calculation units is operated by
the collaborative drive mode,
a recoverable mode in which the torque is output to the motor drive unit of the own system based on a calculation result of itself without using the information by the communication between the systems, when there is a possibility of returning to a normal operation of the focus control calculation unit, and
a failure determination mode in which the torque is output to the motor drive unit of the control calculation unit corresponding to the control calculation unit of the back system of the system where a failure occurred, when the failure of the focus control calculation unit is confirmed,
wherein
a predetermined return waiting time of the communication between the systems and a predetermined return waiting time of the communication between the actuators from the stop of the focus control calculation unit are set twice, and
wherein
in a configuration in which the return waiting time of the communication between the systems is set shorter than the return waiting time of the communication between the actuators,
when the communication between the adjacent systems is interrupted due to a stop of the focus control calculation unit,
the control calculation unit of the back system of the focus control calculation unit operates in the recoverable mode for a period equal to or longer than a predetermined return waiting time of the communication between the systems from the stop of the focus control calculation unit, and
when the communication between the adjacent actuators is interrupted due to the stop of the focus control calculation unit,
the cooperative control calculation unit of the focus control calculation unit continues the control calculation for a period equal to or longer than a predetermined return waiting time of the communication between the actuators from the stop of the focus control calculation unit.
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