WO2019233004A1 - Real-time synchronous networked control device and method for distributed drive electric vehicle - Google Patents

Abstract

A real-time synchronous networked control device for a distributed drive electric vehicle comprises a plurality of sensor nodes of a vehicle, a vehicle controller, and a plurality of actuator nodes of the vehicle. The vehicle controller comprises a receiving module, a controller module, a time trigger, a scheduling table storage module, a scheduler module, and a sending module, wherein an input terminal of the receiving module is connected to each sensor node of the vehicle via a CAN protocol network, and an output terminal is connected to the controller module; an input terminal of the scheduler module is separately connected to the scheduling table storage module and the time trigger, and an output terminal is separately connected to the controller module and the sending module; an output terminal of the controller module is connected to the sending module; and the sending module is connected to each actuator node of the vehicle via the CAN protocol network. A use method of the real-time synchronous networked control device for a distributed drive electric vehicle is further provided. The device and use method thereof effectively resolves the issue of information non-synchronization caused by CAN protocol in-vehicle networks, reduces network-induced delays, and improves the synchronization and real-time performance of wheel drive controls.

Description

Real-time synchronous networked control device and method for distributed driving electric vehicle Technical field

The invention relates to a control device for a distributed drive electric vehicle, and in particular to a real-time synchronous networked control device and method for a distributed drive electric vehicle.

Background technique

Distributed driving electric vehicle refers to a new configuration vehicle in which each driving wheel is independently driven by a motor. Compared with traditional vehicle machinery and hydraulic systems, the motor has faster torque response capability and higher torque control accuracy; distributed Driving electric vehicles has the advantage of flexible and controllable torque of each driving wheel, so it has great potential in vehicle dynamics control and energy saving.

At present, the advantages and development of distributed-drive electric vehicles have attracted people's attention, especially in the field of low-floor passenger cars, engineering vehicles and special vehicles. For automobiles that adopt distributed drive of in-wheel motors, the reasonable control of each motor's The torque output can realize the optimization of vehicle driving efficiency, improvement of power performance, tire anti-skid rotation and improvement of handling and stability, etc., so as to improve the overall performance and cost performance of the vehicle, which has become a new research hotspot.

Compared with traditional cars, the core task of distributed drive electric vehicles is to achieve a reasonable distribution of wheel torque. In order to achieve a reasonable distribution of wheel torque, a large amount of wheel and vehicle state information needs to be collected in the project, torque commands are generated through reasonable control and torque distribution strategies, and the torque commands are distributed to each drive motor, and each drive motor implements the torque command . In order to handle the real-time exchange of a large amount of status and command information between various electronic units, the CAN protocol vehicle network is usually used as a communication means. On the one hand, the use of the CAN protocol vehicle network provides convenient data interaction capabilities for system integrated control, but it also introduces new problems, such as network-induced delays and information out-of-sync issues. These problems will inevitably reduce the real-time and synchronization of the wheel drive control, affecting the vehicle's dynamics and handling stability; the CAN protocol network induced delay will cause the 4-wheel independent drive electric vehicle to have reduced handling performance or even instability. Aiming at the problem of network-induced delay, robust control can improve the stability of the system to a certain extent. However, due to the problem of network-induced information asynchrony, it cannot meet the actual needs of distributed driving electric vehicles. At present, most of the existing CAN vehicle-mounted networks focus on solving the CAN protocol network induced delay and bandwidth utilization issues, without considering the problem of network induction information asynchrony, which has certain limitations and cannot meet the requirements of distributed drive electric The actual application needs of automotive control.

Summary of the Invention

The purpose of the present invention is to overcome the shortcomings of the prior art and provide a real-time synchronous networked control device and method for distributed driving electric vehicles, which effectively solves the problem of information asynchrony induced by the CAN protocol on-board network and effectively reduces the network induction. The delay improves the synchronization and real-time of the wheel drive control, and provides technical support for ensuring the maneuverability and safety of the distributed drive vehicle.

The object of the present invention is achieved by the following technical solutions: a real-time synchronous networked control device for distributed driving electric vehicles, including multiple sensor nodes of a vehicle, a vehicle controller, and multiple actuator nodes of the vehicle; the vehicle control The device includes a receiving module, a controller module, a time trigger, a schedule storage module, a scheduler module, and a sending module;

The input end of the receiving module is connected to various sensor nodes of the vehicle through the CAN protocol network, and receives driver instructions. The output end of the receiving module is connected to the controller module; the input end of the dispatcher module is respectively connected to the schedule storage module. Connected to a time trigger, used to calculate a scheduling command according to the schedule stored in the schedule storage module under the management of the time trigger, and the output of the scheduler module is connected to the controller module and the sending module, respectively; The controller module, under the dispatch command, calculates and generates a torque control command according to the driver instruction information from the receiving module and the vehicle / wheel state information collected by each sensor node of the vehicle; the output end of the controller module is connected to the sending module The sending module is connected to each actuator node of the vehicle through the CAN protocol network.

Further, the time trigger manages the scheduler module by generating a periodic trigger signal.

The control method of a real-time synchronous networked control device for a distributed driving electric vehicle includes the following steps:

S1. Multiple sensor nodes of the vehicle collect vehicle / wheel status information in real time and transmit it to the receiving module through the CAN protocol network;

S2. The receiving module transmits the real-time vehicle / wheel state information to the controller module together with the driver's instruction;

S3. Under the signal of the time trigger, the scheduler module calculates the scheduling command according to the schedule and transmits it to the controller module or the sending module;

S4. Under the dispatch command of the dispatcher module, the controller module uses the driver's instruction information and the vehicle / wheel state information collected by each sensor node of the vehicle to calculate and generate a torque control command, which is transmitted to the sending module;

S5. Under the dispatching command of the dispatcher module, the sending module transmits the torque control command to the various actuator nodes of the vehicle in real time through the CAN protocol network to control the action of the electric vehicle.

Further, the schedule includes a plurality of basic periods, and the basic periods are responsible for sending management information.

Further, the base period length T _base-cycle should satisfy the following scheduling inequality:

T _base-cycle ＞ max [∑ (T _message )];

Among them, T _message indicates the information transmission time in the basic period, Σ () indicates the sum operation, and max [] indicates the maximum value operation.

The beneficial effect of the present invention is that the present invention adopts an active scheduling mode based on a schedule, which can effectively solve the problem of asynchronous sending of state information induced by the network, and effectively improve the synchronization of the wheel drive control; by using the schedule, the basic period and the scheduling inequality The criterion can effectively suppress the problem of network-induced information delay and effectively ensure the real-time nature of wheel drive control.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram of a device according to the present invention;

2 is a flowchart of a method according to the present invention;

FIG. 3 is an analytic diagram of torque distribution execution of the distributed driving electric vehicle in the embodiment;

4 is an example of a scheduling table designed according to the scheduling strategy proposed by the present invention;

FIG. 5 is an implementation effect diagram of networked control using a traditional control scheme; FIG.

FIG. 6 is an implementation effect diagram of networked control using the control scheme proposed by the present invention.

Detailed ways

The technical solution of the present invention is described in further detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the following.

As shown in FIG. 1, a real-time synchronous networked control device for distributed driving electric vehicles includes multiple sensor nodes of a vehicle, a vehicle controller, and multiple actuator nodes of the vehicle; the vehicle controller includes a receiving module and a controller Modules, time triggers, schedule storage modules, scheduler modules, and sending modules;

The input end of the receiving module is connected to various sensor nodes of the vehicle through the CAN protocol network, and receives driver instructions. The output end of the receiving module is connected to the controller module; the input end of the dispatcher module is respectively connected to the schedule storage module. Connected to a time trigger, used to calculate a scheduling command according to the schedule stored in the schedule storage module under the management of the time trigger, and the output of the scheduler module is connected to the controller module and the sending module, respectively; The controller module, under the dispatch command, calculates and generates a torque control command according to the driver instruction information from the receiving module and the vehicle / wheel state information collected by each sensor node of the vehicle; the output end of the controller module is connected to the sending module The sending module is connected to each actuator node of the vehicle through the CAN protocol network.

The time trigger manages the scheduler module by generating a periodic trigger signal.

As shown in FIG. 2, the method for controlling a real-time synchronous networked control device for a distributed driving electric vehicle includes the following steps:

S1. Multiple sensor nodes of the vehicle collect vehicle / wheel status information in real time and transmit it to the receiving module through the CAN protocol network;

S2. The receiving module transmits the real-time vehicle / wheel state information to the controller module together with the driver's instruction;

S3. Under the signal of the time trigger, the scheduler module calculates the scheduling command according to the schedule and transmits it to the controller module or the sending module;

S4. Under the dispatch command of the dispatcher module, the controller module uses the driver's instruction information and the vehicle / wheel state information collected by each sensor node of the vehicle to calculate and generate a torque control command, which is transmitted to the sending module;

S5. Under the dispatching command of the dispatcher module, the sending module transmits the torque control command to the various actuator nodes of the vehicle in real time through the CAN protocol network to control the action of the electric vehicle.

The schedule includes a plurality of basic periods, and the basic periods are responsible for sending management information.

The basic cycle length T _base-cycle should satisfy the following scheduling inequality:

T _base-cycle ＞ max [∑ (T _message )];

Among them, T _message indicates the information transmission time in the basic period, Σ () indicates the sum operation, and max [] indicates the maximum value operation.

In the embodiment of the present application, a four-wheeled distributed drive electric vehicle networked control system structure is taken as an example. The control system of the electric vehicle includes four motor sensor nodes and four motor actuator nodes (Note: In practical applications, Motor sensor nodes and motor actuator nodes can be integrated in the motor controller node assembly), vehicle controllers, CAN networks, and directly connected sensors. The vehicle controller collects the rotation speed signals and driver command information of the four motor sensor nodes through the CAN network, and calculates the torque control command based on the obtained vehicle / wheel state information, according to the vehicle dynamics control requirements and the corresponding control strategy. The CAN network sends the calculated torque control commands to the four motor actuator nodes.

FIG. 3 is an implementation analysis diagram of torque distribution of a distributed-drive electric vehicle according to an embodiment. The process of torque distribution of a four-wheeled distributed-drive electric vehicle is as follows: First, four motor speed sensors collect the current motor speed signals and send them to the CAN network through After receiving the four motor speed signals and driver instructions, the vehicle controller and the receiving module of the vehicle controller calculate and generate torque control commands according to the vehicle dynamics control requirements and the corresponding torque distribution strategy. The torque command is sent to the motor controller to execute the torque command to realize the drive control of the vehicle. In order to complete the above drive control process and ensure the stability of the vehicle, the following two points must be guaranteed: the first is to ensure the real-time performance of the feedback control from the motor speed to the torque command, and the second is to ensure the synchronization of the four motors to execute the torque command. . Therefore, network-induced delay and out-of-sync issues must be effectively suppressed to ensure the real-time and synchronization of wheel drive control.

According to the technical solution of the present invention, the controller module accepts the management of the scheduling command generated by the scheduler module when processing the torque control command. At the same time, other sensors and executor nodes accept the management of scheduling commands sent by the scheduler module when performing tasks. Through the synergy of control and scheduling, the real-time and synchronization of status information and command information transmission can be guaranteed, and network induced asynchrony and suppression are suppressed. The time delay effectively guarantees the real-time and synchronization of the wheel drive control. The vehicle controller in the project can be implemented by a 16-bit or higher microcontroller chip with an integrated CAN module.

As shown in FIG. 4, a scheduling table designed for this example according to the scheduling strategy proposed by the present invention, the scheduling table is composed of a basic period. In this example, the CAN bus baud rate is set to 250 kbps, the system sampling period is 10 ms, and the basic period is set to 5 ms. Each sampling period contains two basic periods, and the management of sampling information transmission is completed in the first basic period. The management of command information transmission is completed in the second basic cycle.

d _j≤8, 可知扩展帧长度最长可为160位。在本例中，一个基本周期要完成发送4条转速信号数据帧和1条调度命令数据帧，发送5条数据帧所需时间为： According to the message frame format specified by CAN2.0B, the extended frame length calculation formula is:

d _j ≤8, it can be known that the extended frame length can be up to 160 bits. In this example, one basic cycle needs to complete sending four speed signal data frames and one scheduling command data frame. The time required to send five data frames is:

That is, the basic period in this example satisfies the scheduling inequality T _base-cycle > max [Σ (T _message )].

Figures 5 to 6 are analysis diagrams of the implementation effects of the networked control in the embodiment of the present invention, wherein FIG. 5 is the implementation effect diagrams of the networked control using the traditional control scheme (without using the scheduler), and FIG. 6 is the control using the present invention. The network control implementation plan of the scheme. By comparison, it can be seen that the solution provided by the present invention effectively solves the problem of asynchronous sending of network information, and at the same time reduces the network induced delay to one sampling period. However, the traditional scheme has large asynchronism and large time-varying delay. In summary, the proposed scheme has obvious technical advantages in ensuring the real-time and synchronization of wheel drive control, and can provide technical support for real-time synchronous control of distributed drive electric vehicles.

It should be noted that the above is only a specific example of the present invention, and the present invention is not limited to the above-mentioned implementation embodiments. Any local changes, equivalent replacements, and improvements made on the spirit and principle of the present invention All should be included in the protection scope of the present invention.

Claims (5)

The real-time synchronous networked control device for distributed driving electric vehicles is characterized in that it includes multiple sensor nodes of a vehicle, a vehicle controller, and multiple actuator nodes of the vehicle; the vehicle controller includes a receiving module, a controller module, Time trigger, schedule storage module, scheduler module and sending module; The input end of the receiving module is connected to various sensor nodes of the vehicle through the CAN protocol network, and receives driver instructions. The output end of the receiving module is connected to the controller module; the input end of the dispatcher module is respectively connected to the schedule storage module. Connected to a time trigger, used to calculate a scheduling command according to the schedule stored in the schedule storage module under the management of the time trigger, and the output of the scheduler module is connected to the controller module and the sending module, respectively; The controller module, under the dispatch command, calculates and generates a torque control command according to the driver instruction information from the receiving module and the vehicle / wheel state information collected by each sensor node of the vehicle; the output end of the controller module is connected to the sending module The sending module is connected to each actuator node of the vehicle through the CAN protocol network. The real-time synchronous networked control device for a distributed drive electric vehicle according to claim 1, wherein the time trigger manages the scheduler module by generating a periodic trigger signal. The control method of a real-time synchronous networked control device for a distributed-drive electric vehicle according to claim 1 or 2, comprising the following steps: S1. Multiple sensor nodes of the vehicle collect vehicle / wheel status information in real time and transmit it to the receiving module through the CAN protocol network; S2. The receiving module transmits the real-time vehicle / wheel state information to the controller module together with the driver's instruction; S3. Under the signal of the time trigger, the scheduler module calculates the scheduling command according to the schedule and transmits it to the controller module or the sending module; S4. Under the dispatch command of the dispatcher module, the controller module uses the driver's instruction information and the vehicle / wheel state information collected by each sensor node of the vehicle to calculate and generate a torque control command, which is transmitted to the sending module; S5. Under the dispatching command of the dispatcher module, the sending module transmits the torque control command to the various actuator nodes of the vehicle in real time through the CAN protocol network to control the action of the electric vehicle. The method for controlling a real-time synchronous networked control device for a distributed-drive electric vehicle according to claim 3, wherein the schedule includes a plurality of basic cycles, and the basic cycles are responsible for sending management information. The control method of a real-time synchronous networked control device for a distributed-drive electric vehicle according to claim 4, wherein the basic cycle length T _base-cycle should satisfy the following scheduling inequality: T _base-cycle ＞ max [∑ (T _message )]; Among them, T _message indicates the information transmission time in the basic period, Σ () indicates the sum operation, and max [] indicates the maximum value operation.

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