Patent ID: 12227233

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Hereinafter, a steering control method of a redundant steering system will be described below with reference to the accompanying drawings through various exemplary embodiments. In such a process, for clarity and convenience in description, thicknesses of lines, sizes of constituent elements, and the like may be illustrated in an exaggerated manner in the drawings. In addition, terms to be described hereinafter have been defined in consideration of functions in the present disclosure, and may differ depending on a user, an operator's intention, or common practice. Therefore, definitions of these terms should be stated in light of details disclosed throughout the present specification.

FIG.1is a block diagram illustrating a redundant motor driven power steering (MDPS) control apparatus of an autonomous vehicle according to a first embodiment of the present disclosure.

Referring toFIG.1, the redundant MDPS control apparatus of the autonomous vehicle according to the first embodiment of the present disclosure includes a first steering controller10and a second steering controller20.

The first steering controller10and the second steering controller20are provided inside a steering control system of the autonomous vehicle.

The first steering controller10and the second steering controller20are formed in pair to provide functional redundancy in the autonomous vehicle. The first steering controller10and the second steering controller20perform steering control according to each command signal input from a driving controller (not illustrated), a column torque sensor (not illustrated), or the like of the autonomous vehicle.

The first steering controller10and the second steering controller20may be configured as parts of the MDPS or an electronic power steering (EPS), but are not specifically limited thereto.

The MDPS and the EPS can be easily practiced by those skilled in the art, and thus a detailed description thereof is omitted.

The first steering controller10and the second steering controller20are connected to the driving controller through controller area network (CAN) communication.

The driving controller inputs a first command signal to the first steering controller10and inputs a second command signal to the second steering controller20.

Accordingly, the first steering controller10and the second steering controller20independently perform steering control according to the first command signal and the second command signal input from the driving controller and then output a first control output and a second control output, respectively, as a result of the steering control.

The first command signal and the second command signal may each be a command steering angle or column torque. For the first command signal and the second command signal, at least one of the command steering angles and the column torque is selectively input depending on whether a driving mode of the autonomous vehicle is an autonomous driving mode or a driver's steering mode.

The first steering controller10and the second steering controller20receive the first command signal and the second command signal, respectively, from the driving controller to perform driving control.

When the first steering controller10receives the first command signal from the driving controller, the first steering controller10performs driving control using the first command signal and generates a first control output as a performance result of the driving control.

When the second steering controller20receives the second command signal from the driving controller, the second steering controller20performs driving control using the second command signal and generates a second control output as a performance result of the driving control.

For example, the first steering controller10and the second steering controller20may generate the first control output and the second control output as control signals. The control signal is used for controlling a motor or the like included in MDPS or EPS.

In some embodiments, the first control output and the second control output may be a command for a current value.

The specific method of generating the first control output and the second control output is obvious to those skilled in the art, and thus detailed descriptions are omitted here.

Meanwhile, the first steering controller10and the second steering controller20receive the first command signal and the second command signal, respectively, from the driving controller as described above. At this time, when an input timing of the first command signal and an input timing of the second command signal match, the first command signal and the second command signal are also synchronized. However, when the input timing of the first command signal and the input timing of the second command signal do not match, the first command signal and the second command signal are not synchronized.

Therefore, when the first steering controller10and the second steering controller20receive the first command signal and the second command signal, respectively, from the driving controller, at least one of the first steering controller10and the second steering controller20compensates a control timing according to the first command signal and the second command signal so that the first control output and the second control output are synchronized.

More specifically, when the first steering controller10and the second steering controller20receive the first command signal and the second command signal, respectively, from the driving controller, the first steering controller10and the second steering controller20exchange alive count values with each other using internal communication.

Here, the alive count value is a count value that indicates a point of time when the CAN signal is input. That is, the alive count value may be checked in a way that the count value is checked at the point when the CAN signal is input while the count value decreases (increases) according to a count cycle.

The first steering controller10and the second steering controller20are connected to the driving controller through CAN communication. Therefore, the first steering controller10and the second steering controller20may exchange the alive count values of the first command signal and the second command signal with each other. The alive count value is a CAN signal.

Therefore, the first steering controller10may check both the alive count value of its first command signal and the alive count value of the second command signal.

In addition, the second steering controller20also may check both the alive count value of its second command signal and the alive count value of the first command signal.

Accordingly, the first steering controller10and the second steering controller20may determine their control timing based on the alive count value of the first command signal and the alive count value of the second command signal, respectively.

In this case, the first steering controller10determines the control timing according to a difference between the alive count value of the first command signal and the alive count value of the second command signal and an alive count cycle in which the alive count increases.

In addition, the second steering controller20determines the control timing according to the difference between the alive count value of the first command signal and the alive count value of the second command signal and the alive count cycle.

For example, in a case where the alive count value of the first dispatch signal is 100 and the alive count value of the second dispatch signal is 98, it appears that the timing of receiving the second command signal in the second steering controller20is slower by 2. In addition, when the alive count cycle is 1 ms, the steering control starting point in time of the second steering controller20comes 2 ms later than the steering control starting point in time of the first steering controller10.

Therefore, the first steering controller10determines the steering control timing to be 2 ms later than the original steering control starting point in time so that the steering control starting point in time of the first steering controller10matches the second steering controller20.

Meanwhile, since the control timing of the second steering controller20comes later than the first steering controller10, the second steering controller20performs the steering control according to the initial control timing.

Hereinafter, referring toFIG.2, the steering control method of the redundant steering system according to the first embodiment of the present disclosure will be described.

FIG.2is a flowchart illustrating the steering control method of the redundant steering system according to the first embodiment of the present disclosure.

Referring toFIG.2, the first steering controller10and the second steering controller20receive the first command signal and the second command signal first, respectively, from the driving controller (S110).

Each of the first steering controller10and the second steering controller20exchanges the alive count values with each other using the internal communication (S120).

Accordingly, the first steering controller10may check both the alive count value of its first command signal and the alive count value of the second command signal.

In addition, the second steering controller20also may check both the alive count value of its second command signal and the alive count value of the first command signal.

Next, each of the first steering controller10and the second steering controller20detects the difference between the alive count value of the first command signal and the alive count value of the second command signal (S130).

Each of the first steering controller10and the second steering controller20determines the control timing so that the first control output and the second control output are synchronized according to the difference between the alive count value of the first command signal and the alive count value of the second command signal and the alive count cycle and then performs the steering control according to the determined control timing (S140).

FIG.3is a block diagram illustrating a redundant MDPS control apparatus of an autonomous vehicle according to a second embodiment of the present disclosure.

Referring toFIG.3, the redundant MDPS control apparatus of the autonomous vehicle according to the second embodiment of the present disclosure includes a first steering controller10and a second steering controller20.

In the second embodiment of the present disclosure, detailed descriptions for the same components as in the first embodiment are omitted.

In the first embodiment of the present disclosure, an example of a case of a system where the first steering controller10and the second steering controller20independently receive the first command signal and the second command signal, respectively, has been described.

However, in the second embodiment of the present disclosure, an example of a case of a system where only the first steering controller10receives a command signal and the first steering controller10transmits the command signal to the second steering controller20through internal communication will be described.

The first steering controller10receives the command signal from the driving controller and then transmits the command signal to the second steering controller20through the internal communication.

In this case, there may be a communication delay between the first steering controller10and the second steering controller20.

Therefore, the first steering controller10transmits the command signal to the second steering controller20, compensates the control timing for a predetermined set time, and then matches the first control output of the first steering controller10and the second control output of the second steering controller20to be synchronized.

Here, the set time is a communication delay time during the internal communication between the first steering controller10and the second steering controller20.

Therefore, the first steering controller10transmits the command signal to the second steering controller20and then performs the steering control after the predetermined communication delay time has elapsed from the original starting point in time of the steering control.

On the other hand, the second steering controller20performs the steering control at its predetermined point of time for the steering control.

Consequently, the first control output of the first steering controller10and the second control output of the second steering controller20are synchronized.

Hereinafter, referring toFIG.4, the steering control method of the redundant steering system according to the second embodiment of the present disclosure will be described.

FIG.4is a flowchart illustrating the steering control method of the redundant steering system according to the second embodiment of the present disclosure.

Referring toFIG.4, the first steering controller10receives the command signal from the driving controller (S210).

Then, the first steering controller10transmits the command signal to the second steering controller20(S220).

Next, the first steering controller10determines the control timing according to the communication delay time between the first steering controller10and the second steering controller20and then performs the steering control (S230). That is, the first steering controller10performs the steering control after the predetermined communication delay time has elapsed from the original starting point in time of the steering control (S230).

On the other hand, the second steering controller20performs the steering control at its predetermined point of time for the steering control.

Therefore, the first steering controller10and the second steering controller20simultaneously start steering control, and the first control output of the first steering controller10and the second control output of the second steering controller20are synchronized.

In this way, the steering control method of the redundant steering system according to the embodiment of the present disclosure improves the performance of the redundant MDPS system by matching the operation timings of the first steering controller and the second steering controller.

The implementations described in the present specification may be performed by, for example, a method or a process, an apparatus, a software program, a data stream, or a signal. Although being discussed only in the context of single-form implementation (e.g., being discussed only as a method), the discussed features may be implemented even in another form (e.g., apparatus or program). The apparatus may be implemented as proper hardware, software, and firmware. The method may be implemented as, for example, an apparatus, such as a processor generally indicating a processing device including a computer, a microprocessor, an integrated circuit, or a programmable logic device. The processor also includes communication devices such as computers, cell phones, personal digital assistants (PDAs), and other devices that facilitate the communication of information between end users.

The present disclosure has been described with reference to exemplary embodiments illustrated in the accompanying drawings, but this is only for exemplary purposes, and those skilled in the art will appreciate that various modifications and other equivalent exemplary embodiments are possible. Thus, the true technical scope of the disclosure should be defined by the following claims.