CN102353535B - Low-power-consumption hardware-in-loop test platform and method for stepless speed changer of vehicle - Google Patents

Abstract

The invention discloses a low-power hardware-in-the-loop test bench for vehicle continuously variable transmission, which includes a target machine, a host machine, a data acquisition unit and a hardware unit; The simulink vehicle transmission model is established in the host computer, and the RTW compiled model is used to download the model to the target machine during operation; the target machine is connected to the inverters corresponding to the drive motor and the load motor respectively, and the target machine makes the drive motor It has the same speed characteristics as the engine and makes the running condition of the load motor close to that of the real vehicle; the data acquisition unit collects the running data of the continuously variable transmission and outputs the data. The present invention utilizes the force balance of the speed change mechanism in the continuously variable transmission to When researching the performance of the control system and hydraulic system, low-power drive motors and load motors are used to replace the engine and high-power loading equipment, and the transmission operates in no-load/light-load conditions, which greatly reduces the construction cost of the test bench.

Description

Low-power hardware-in-the-loop test bench and test method for vehicle continuously variable transmission

technical field

The invention relates to a transmission test device, in particular to a low-power consumption hardware-in-the-loop test bench for a vehicle continuously variable transmission.

Background technique

The design goal of conventional vehicle continuously variable transmission test bench is to imitate the actual driving conditions of the vehicle as much as possible. The test bench is composed of engine, transmission, flywheel, loading equipment, etc., in which the engine can be replaced by a motor with equivalent power, and the flywheel and loading equipment can be replaced by a motor that meets the requirements. Instead of a motor, this kind of test bench has a complex structure, high cost, and large energy consumption during operation.

At present, one focus of domestic research on continuously variable transmissions is the control system and hydraulic system. Due to the force balance relationship of the transmission mechanism of the continuously variable transmission itself, the operating status of the hydraulic system is almost not affected by the load of the transmission. Normal speed ratio control and clamping force control can also be performed under load conditions.

In order to reduce the cost of test construction and operation, when the efficiency and steel belt life of the CVT are not studied, it is not necessary to apply the same load as the actual working condition, but as long as the speed and speed ratio change are close to the real situation. . To change the power source to a low-power motor, it is only necessary to ensure that the transmission can run under no-load or light-load conditions, and the loading equipment is also changed to a low-power motor, while reducing or canceling the inertia flywheel, which greatly reduces the construction of the test bench. cost.

Rapid control prototyping is the current trend in the research of control strategies and control algorithms. Commercial platforms are relatively expensive. Therefore, using the xPC target function of MATLAB software to design vehicle CVT low-power hardware-in-the-loop test benches is a low-cost method worth considering. At present, there is no hardware-in-the-loop test bench for CVT based on no-load/light-load.

Contents of the invention

In view of this, one of the objectives of the present invention is to provide a low-power consumption hardware-in-the-loop test bench for vehicle continuously variable transmission, which utilizes the force balance relationship of the transmission mechanism itself in the continuously variable transmission to test the performance of the control system and hydraulic system. During the research, a low-power driving motor and a load motor are used to replace the engine and high-power loading equipment, which greatly reduces the construction cost of the test bench; the second purpose of the present invention is to provide a low-power hardware-in-the-loop test for a continuously variable transmission of a vehicle method.

The purpose of the present invention is achieved through the following technical solutions:

The vehicle CVT low-power hardware-in-the-loop test bench includes a target machine, a host machine, a data acquisition unit and a hardware unit;

The hardware unit includes a drive motor, a continuously variable transmission and a load motor connected in sequence, and a simulink vehicle transmission model is established in the host computer, and the simulation parameters of the vehicle transmission model are input through the host computer. During operation, the model is compiled using RTW Download to the target machine;

The target machine is respectively connected to the drive motor and the load motor through different communication interfaces. Through the setting of the simulation parameters of the vehicle transmission model, the target machine makes the drive motor have the same speed characteristics as the engine, and at the same time makes the load motor run. Close to real vehicle operation;

The data acquisition unit collects the clamping force of the real CVT and the speed signals of the driving and driven wheels through the sensor, and inputs the vehicle transmission simulation model for studying the control effect of the clamping force control algorithm and the speed ratio control algorithm, and for calculating the vehicle speed and speed ratio. Engine speed, the obtained data is saved to the target machine or uploaded to the host machine.

Further, the control unit realizes the speed control of the driving motor and the load motor through the frequency converter I and the frequency converter II respectively;

Further, the data acquisition unit includes an acquisition card and a CVT interface board, the CVT interface board is connected to the sensor output terminal on the continuously variable transmission, and outputs the collected operating data to the target machine through the acquisition card;

Further, the simulink vehicle transmission model includes a driver, an engine, a controller, driving resistance, driving dynamics, and motion control modules.

Further, the simulation parameters include engine, CVT and road condition parameters, calculate engine torque, running resistance, speed ratio and system pressure, and further calculate target vehicle speed and target engine speed.

Two of the purpose of the present invention is achieved through the following technical solutions:

The vehicle CVT low-power hardware-in-the-loop test method includes the following steps:

1) Connect the drive motor, continuously variable transmission and load motor in sequence to form a hardware unit;

2) Establish a simulink vehicle transmission model in the host machine, and input the simulation parameters of the vehicle transmission model, and download the model to the target machine using RTW compilation;

3) Run the target machine program, the hardware unit starts to run, the driving motor has the same speed characteristics as the engine, and at the same time, the running condition of the load motor is close to that of the actual vehicle;

4) The data acquisition unit collects the real CVT clamping force and the speed signal of the main and driven wheels through the sensor, and inputs the vehicle transmission simulation model to study the control effect of the clamping force control algorithm and the speed ratio control algorithm, and to calculate the vehicle speed and engine speed. Speed, the obtained data is saved to the target machine or uploaded to the host machine.

The beneficial effects of the present invention are:

1. Utilizing the force balance relationship of the transmission mechanism itself in the continuously variable transmission, when conducting performance research on the control system and hydraulic system, the low-power drive motor and load motor are used to replace the engine and high-power loading equipment, and the transmission is in the no-load/light-load state operation, greatly reducing the construction cost of the test bench;

2. Compared with the pure model simulation system, the present invention includes the transmission in the hardware-in-the-loop to improve the operation accuracy;

3. The present invention adopts a host machine-target machine structure based on xPC to ensure the real-time performance of system operation.

4. The system jointly controls the transmission and the motor. By controlling the frequency converter, the motor has the same speed characteristics as the engine. At the same time, it controls the load motor, so that the operation of the test bench is close to that of the real vehicle. It has most of the functions of the conventional test bench. Including the development and verification of control strategies and control algorithms, it is convenient for performance testing and analysis of hydraulic actuators, achieving low energy consumption and low cost.

Other advantages, objects and features of the present invention will be set forth in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the investigation and research below, or can be obtained from Taught in the practice of the present invention. The objects and other advantages of the invention will be realized and attained by the following description and claims.

Description of drawings

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail below in conjunction with the accompanying drawings, wherein:

Fig. 1 is a schematic diagram of the test bench structure of the present invention;

Fig. 2 is a schematic diagram of the dynamic model of the clutch and the torque converter in the lock-up condition of the present invention.

Detailed ways

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood that the preferred embodiments are only for illustrating the present invention, but not for limiting the protection scope of the present invention.

As shown in Figure 1, the low-power consumption hardware-in-the-loop test bench of the vehicle continuously variable transmission of the present invention includes a host machine 1, a target machine 2, a data acquisition unit 3 and a hardware unit;

The hardware unit includes a drive motor 5, a continuously variable transmission 6, and a load motor 7 connected in sequence. By establishing a simulink vehicle transmission model in the host computer 1, the simulation parameters of the vehicle transmission model are input through the host computer. When running, use RTW Download the compiled model to the target machine;

RTW is a tool software of MATLAB, which can compile and automatically download the simulink model to the target machine.

XPC is a functional module of simulink, which is used to implement a host-target hardware-in-the-loop structure. The target machine is a general-purpose PC compatible machine, and the simulink model is built on the host machine, compiled through RTW, and downloaded to target machine and run in real time. The target machine is bare metal, without operating systems such as windows, and only runs the compiled model program to ensure the running speed, so it can run in real time.

The target machine is connected to the drive motor and the load motor through different communication interfaces. The simulink vehicle transmission model includes the driver, engine, controller, driving resistance, driving dynamics, and motion control modules. By setting the simulation parameters of the vehicle transmission model (the simulation parameters include engine, CVT and road condition parameters), the engine torque, driving resistance, speed ratio and system pressure are calculated, and the target vehicle speed and target engine speed are further calculated.

The target machine makes the driving motor have the same speed characteristics as the engine, and simultaneously makes the operating condition of the load motor close to the actual vehicle operation; Motor speed control.

The data acquisition unit collects the operation data of the continuously variable transmission through the sensor, and outputs the data and saves them to the target machine or uploads them to the host machine. In the present embodiment, the data acquisition unit includes an acquisition card and a CVT interface board 4, and the CVT interface board 4 is connected with the sensor output terminal on the continuously variable transmission, and the running data collected is output to the target machine through the acquisition card.

Simulink is a visual simulation tool in MATLAB. It is a block diagram design environment based on MATLAB. It is a software package for dynamic system modeling, simulation and analysis. It is widely used in linear systems, nonlinear systems, digital control and In modeling and simulation of digital signal processing. Simulink can model with continuous sample time, discrete sample time, or a mixture of the two. It also supports multirate systems, that is, different parts of the system have different sample rates. In order to create a dynamic system model, Simulink provides a graphical user interface (GUI) for building a model block diagram. This creation process can be completed by simply clicking and dragging the mouse, which provides a faster, more straightforward way , and the user can immediately see the simulation results of the system.

Compared with the pure simulation model fully running on the PC, the vehicle continuously variable transmission low power consumption hardware-in-the-loop test bench of the present invention has the following characteristics:

1) Replace the CVT model with the actual CVT, and the simulation effect is closer to the real situation than the pure software environment;

2) The motion control module calculates the target engine speed and vehicle speed according to the dynamics of the transmission system. The motion control module controls the frequency converter to make the drive motor and load motor speed track the target engine speed and vehicle speed. The operating characteristics of the test bench are similar to the actual vehicle;

3) The CVT interface board is the signal conversion interface between the CVT and the acquisition card, which converts the sensor signal on the CVT into a signal that can be collected by the acquisition card, and drives the solenoid valve according to the control signal output by the acquisition card. The solenoid valve includes a clamping force valve and a speed ratio valve related to the transmission mechanism. The clamping force valve is used to control the clamping force of the driven wheel, and the speed ratio valve is used to control the clamping force of the driving wheel. The driving wheel and the driven wheel Both are composed of a fixed plate and a sliding plate. By controlling the two valves, the clamping force ratio of the driving wheel and the driven wheel can be adjusted, and the working radius of the driving wheel and the driven wheel can be changed, so that the speed ratio can be continuously changed.

Based on the above test bench, the vehicle continuously variable transmission low power consumption hardware-in-the-loop testing method of the present invention comprises the following steps:

1) Connect the drive motor, continuously variable transmission and load motor in sequence to form a hardware unit;

2) Establish a simulink vehicle transmission model in the host machine, and input the simulation parameters of the vehicle transmission model, and download the model to the target machine using RTW compilation;

3) Run the target machine program, the hardware unit starts to run, the driving motor has the same speed characteristics as the engine, and at the same time, the running condition of the load motor is close to that of the actual vehicle;

4) Monitor the test process, and save the data in the target machine or upload it to the host machine;

5) After the test run is over, process the test data.

As shown in Figure 2, the dynamic model of the clutch and torque converter under the lock-up condition is:

；

;

In the formula, the speed ratio i is calculated by collecting the input/output shaft speed of the transmission on the test bench.

The most common structure of CVT is: engine-clutch-torque converter-transmission mechanism-final reduction-wheel. Since clutch control and torque converter control are common technologies and not unique to CVT, they are not the focus of CVT research. Usually, the research on CVT control mainly focuses on the research of the clutch closed and torque converter locked state. At this time, the control The content includes speed ratio control and clamping force control, which is the unique control content of CVT.

The engine speed and vehicle speed are obtained from the dynamic simulation as the target speeds of the drive motor and the load motor of the test bench, respectively. Due to the force balance relationship of CVT itself, the speed ratio change rate and control characteristics are only related to the speed, not the transmitted torque. Therefore, as long as the speed characteristics of the drive motor are the same as the engine speed, and the speed of the load motor is the same as the speed of the driving wheel, it can be achieved. Accurately reflect the speed ratio characteristics of CVT.

The engine speed and vehicle speed are simulated through the above equations, and the drive motor speed is tracked to the calculated engine speed through the frequency converter, and the load motor speed is adjusted to track the wheel speed corresponding to the target vehicle speed. At this time, the CVT works at the same engine speed and vehicle speed as the actual working conditions.

Finally, it is noted that the above embodiments are only used to illustrate the technical solutions of the present invention without limitation. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be carried out Modifications or equivalent replacements, without departing from the spirit and scope of the technical solution, should be included in the scope of the claims of the present invention.

Claims (5)

1. A low-power hardware-in-the-loop test bench for vehicle continuously variable transmission, characterized in that: the test bench includes a target machine, a host machine, a data acquisition unit and a hardware unit; The hardware unit includes a drive motor, a continuously variable transmission and a load motor connected in sequence, and a simulink vehicle transmission model is established in the host computer, and the simulation parameters of the vehicle transmission model are input through the host computer. During operation, the model is compiled using RTW Download to the target machine; The target machine is respectively connected to the drive motor and the load motor through different communication interfaces. Through the setting of the simulation parameters of the vehicle transmission model, the target machine makes the drive motor have the same speed characteristics as the engine, and at the same time makes the load motor run. Close to real vehicle operation; The data acquisition unit collects the clamping force of the real CVT and the speed signals of the driving and driven wheels through the sensor, and inputs the vehicle transmission simulation model for studying the control effect of the clamping force control algorithm and the speed ratio control algorithm, and for calculating the vehicle speed and speed ratio. Engine speed, the obtained data is saved to the target machine or uploaded to the host machine; The control unit realizes the speed control of the driving motor and the load motor through the frequency converter I and the frequency converter II respectively. 2. The vehicle CVT low-power consumption hardware-in-the-loop test bench according to claim 1, characterized in that: the data acquisition unit includes an acquisition card and a CVT interface board, and the CVT interface board is connected to the CVT interface board on the continuously variable transmission. The output terminals of the sensors are connected, and the collected operation data is output to the target machine through the acquisition card. 3. The vehicle CVT low power consumption hardware-in-the-loop test bench according to claim 1 and 2, is characterized in that: the simulink vehicle transmission model includes driver, engine, controller, driving resistance, driving dynamics, Motion Control Module. 4. The vehicle CVT low power consumption hardware-in-the-loop test bench according to claim 3, characterized in that: the simulation parameters include engine, CVT and road condition parameters for calculating engine torque, driving resistance, speed ratio and system pressure, and further calculate the target vehicle speed and target engine speed. 5. The low power consumption hardware-in-the-loop test method of a vehicle continuously variable transmission, characterized in that: comprising the following steps: 1) Connect the drive motor, continuously variable transmission and load motor in sequence to form a hardware unit; 2) Establish a simulink vehicle transmission model in the host machine, and input the simulation parameters of the vehicle transmission model, and download the model to the target machine using RTW compilation; 3) Run the target machine program, the hardware unit starts to run, the driving motor has the same speed characteristics as the engine, and at the same time, the running condition of the load motor is close to that of the actual vehicle; 4) The data acquisition unit collects the clamping force of the real CVT and the speed signals of the main and driven wheels through the sensor, and inputs the vehicle transmission simulation model to study the control effect of the clamping force control algorithm and the speed ratio control algorithm, and to calculate the vehicle speed and Engine speed, the obtained data is saved to the target machine or uploaded to the host machine.

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