CN103162971B - Electric motor car driving process wireless test system - Google Patents

Abstract

The wireless test system for the electric vehicle running process relates to an electric performance testing instrument, which includes a sensor group, which is arranged on the electric vehicle to be tested, and collects the original data during the driving process of the electric vehicle to be tested; a wireless communication unit collects the sensor group to The original data is transmitted to the signal acquisition mechanism; the signal acquisition mechanism is used to receive the original data collected by the sensor group, perform data processing on the original data, and store and display the processed data; the signal analysis system receives the signal acquisition mechanism Send the data, analyze and process the data, and output the test results. It can exchange data during the driving process of medium and large electric vehicles through the wireless communication unit, and collect, analyze and record the data in a unified manner, and output various test results during the driving process of electric vehicles, which is convenient for testers to observe.

Description

Wireless test system for electric vehicle driving

technical field

The invention relates to an electric performance testing instrument, in particular to a test and analysis system for the driving process of medium and large electric vehicles such as electric cars, electric trucks, and electric passenger cars.

Background technique

For the test of the electric vehicle driving process, when the communication bus protocol is not open, or the signals provided in the communication bus cannot meet the requirements, such as the signal update frequency is low, or the number of signals is insufficient, which brings inconvenience to the test analysis. For medium and large electric vehicles, the body is large, and the sensors are distributed in different parts of the vehicle. It is difficult to connect all the sensors to the test analyzer. In addition, in the process of experimental research, various components and signal lines need to be adjusted frequently, which is very inconvenient and easy to cause failure.

There are still some technical rationality problems in the existing electric vehicle driving process test system: (1) Some instruments do not have recording function, even if there is recording function, the data collection of each instrument is not synchronized, which brings errors to performance analysis. (2) For vehicle performance analysis, signal acquisition is required to have high real-time and sampling frequency, and it is difficult to make all the instruments purchased have this function. (3) Since the sensors and corresponding instruments are distributed in different parts of the vehicle, it is not convenient for the tester to observe at the same time. (4) Since the instruments are not designed for electric vehicles, they are independent of each other, cannot work together, and cannot directly reflect the driving status of the vehicle, such as speed ratio calculation, slope calculation, power and efficiency analysis, etc. These problems bring difficulties to the performance analysis of electric vehicles during driving.

Contents of the invention

The purpose of the present invention is to provide a wireless test system for the driving process of electric vehicles, which can interact with the data during the driving process of medium and large electric vehicles through the wireless communication unit, and uniformly collect, analyze and record the data, and output electric Various test results during the driving process of the car are convenient for the tester to observe.

The purpose of the present invention is achieved by such a technical solution, which includes a sensor group, a wireless communication unit, a signal acquisition mechanism and a signal analysis system;

The sensor group is arranged on the electric vehicle to be tested, and collects the original data during the driving process of the electric vehicle to be tested;

The wireless communication unit transmits the raw data collected by the sensor group to the signal collection mechanism;

The signal acquisition mechanism is used to receive the raw data collected by the sensor group, perform data processing on the raw data, and store and display the processed data;

The signal analysis system receives the data sent by the signal acquisition mechanism, analyzes and processes the data, and outputs the test results.

Further, the signal acquisition mechanism includes a signal acquisition initialization module, the signal acquisition initialization module is used to set the sensor signal acquisition channel, acquisition frequency, storage parameters and vehicle parameters; vehicle parameters include wheel rolling radius, motor pulse number per week, wheel Pulses per week.

Further, the sensor group includes a voltage sensor, a current sensor, a motor speed sensor, a wheel speed sensor, an ambient temperature sensor, a measuring point temperature sensor, an equivalent acceleration sensor and a driving operation signal sensor; the driving operation signal sensor includes an accelerator pedal signal sensor, brake signal sensor and gear signal sensor.

Further, the signal analysis system includes a road slope real-time calculation module, and its slope calculation formula is:

$\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arcsin</span>}<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; a</span>}}{\mathrm{<span\; class="notranslate">\; g</span>}}<span\; class="notranslate">\; )</span>$

Among them: θ is the slope angle, a _e is the equivalent acceleration, that is, the output value of the acceleration sensor, a is the vehicle acceleration, and g is the gravitational acceleration.

Further, the signal analysis system includes a transmission state monitoring module, which is used to monitor the continuous and rapid changes of the motor speed and the transmission speed ratio during the shifting process, calculate the transmission ratio according to the motor speed and the wheel speed, and calculate the transmission ratio according to the speed ratio change and the motor working condition. Points to monitor transmission performance, working status and fault information, to calculate wear and smoothness, and motor working condition points include current signals and speed signals.

Further, the signal analysis system includes a driving analysis module, which analyzes and calculates the impact of driving habits on the mileage of the vehicle according to the accelerator pedal signal, brake signal and gear signal during driving.

Further, the signal analysis system includes an ambient temperature and measuring point temperature testing module, which performs temperature rise performance analysis according to the ambient temperature and measuring point temperature for specific road conditions.

Further, the signal analysis system includes a battery discharge capacity analysis module, which calculates the actual discharge capacity of the battery according to the change curves of current and voltage, and analyzes the actual performance of the battery.

Further, the signal analysis system includes a driving condition analysis module, which is used to analyze and calculate battery power, motor operating point and motor efficiency, and use vehicle driving equations to estimate current road conditions.

Owing to adopting above-mentioned technical scheme, the present invention has following advantage:

The invention can uniformly receive various data collected by sensors, record various collected original data, and the wireless communication module sends the collected original data to a signal analysis system. For medium and large electric vehicles, the present invention solves the problem that the sensors are distributed in different positions of the vehicle due to the large vehicle body, making wiring difficult. By setting the collection mode, the present invention can also unify the channel, frequency and data format of data collection, so that the collected data can be synchronized, which is convenient for data analysis. The signal analysis system analyzes and processes the collected data, and directly outputs the electric vehicle test results, which is convenient for testers to observe. The signal analysis system has powerful analysis functions and can meet all test requirements for electric vehicle tests. Function to edit, add or delete some test modules, strong expansibility.

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 It is 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

The accompanying drawings of the present invention are described as follows.

Fig. 1 is a structural representation of the present invention;

Fig. 2 is the test flowchart of the present invention;

Fig. 3 is a schematic structural diagram of an embodiment of a signal acquisition mechanism;

Fig. 4 is the circuit diagram of the power supply of a kind of embodiment of signal acquisition mechanism;

Fig. 5 is the circuit diagram of the processor of a kind of embodiment of signal acquisition mechanism;

Fig. 6 is a circuit diagram of a wireless communication interface of an embodiment of the signal acquisition mechanism;

Fig. 7 is a circuit diagram of a memory of an embodiment of the signal acquisition mechanism.

Detailed ways

The present invention will be further described below in conjunction with drawings and embodiments.

The wireless test system for the electric vehicle driving process, as shown in Figure 1, includes a sensor group, a wireless communication unit, a signal acquisition mechanism and a signal analysis system;

The sensor group is arranged on the electric vehicle to be tested, and collects raw data during the driving process of the electric vehicle to be tested.

The wireless communication unit transmits the raw data collected by the sensor group to the signal collection mechanism. The wireless communication unit may include a signal receiver connected with the signal collecting mechanism and a plurality of wireless transmitters connected with the sensor. One or more sensors send data to the wireless receiver through a wireless transmitter, and then to the signal acquisition unit, which solves the wiring problem of the sensor data transmission line.

The signal acquisition mechanism is used to receive the raw data collected by the sensor group, perform data processing on the raw data, and store and display the processed data.

The signal analysis system receives the data sent by the signal acquisition mechanism, analyzes and processes the data, and outputs the test results. The signal analysis system can be a separate upper computer, and the upper computer can transmit data with the signal acquisition mechanism, or it can be integrated on the signal acquisition mechanism.

The signal acquisition mechanism includes a signal acquisition initialization module, the signal acquisition initialization module is used to set the sensor signal acquisition channel, acquisition frequency, storage parameters and vehicle parameters; vehicle parameters include wheel rolling radius, motor pulse number per week, wheel weekly number of pulses.

The sensor group includes a voltage sensor, a current sensor, a motor speed sensor, a wheel speed sensor, an ambient temperature sensor, a measuring point temperature sensor, an equivalent acceleration sensor and a driving operation signal sensor; the driving operation signal sensor includes an accelerator pedal signal sensor, Brake signal sensor and gear signal sensor.

Common inclination sensors and acceleration sensors on the market are essentially equivalent acceleration sensors, whose output signal is the superposition of vehicle acceleration and road gradient, which cannot be directly used to measure the road gradient during vehicle driving, and can only be used in a static and constant speed state. down to measure the angle. The invention measures the equivalent acceleration sensor signal and the wheel speed signal at the same time, and the road slope real-time calculation module calculates the vehicle acceleration according to the change rate of the wheel speed, and subtracts the vehicle acceleration factor from the signal of the equivalent acceleration sensor. The road slope can be calculated, and its slope calculation formula is:

$\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arcsin</span>}<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; a</span>}}{\mathrm{<span\; class="notranslate">\; g</span>}}<span\; class="notranslate">\; )</span>$

Among them: θ is the slope angle, a _e is the equivalent acceleration, that is, the output value of the acceleration sensor, a is the vehicle acceleration, and g is the gravitational acceleration.

The transmission status monitoring module is used to monitor the continuous and rapid changes of the motor speed and the transmission speed ratio during the shifting process, calculate the transmission ratio according to the motor speed and the wheel speed, and monitor the transmission performance, working status and faults according to the speed ratio change and the motor operating point information, calculate the wear and smoothness, and the motor operating point includes the current signal and the speed signal.

The current test of the continuation mileage of a single charge of an electric vehicle is relatively extensive. The driver drives on a designated road, and when the battery is undervoltage, the continuation mileage is recorded. Since factors such as operating habits, driving speed, and the number of times of braking have an important impact on the continuation mileage, the driving analysis module of the present invention can analyze and calculate the driving habits according to the accelerator pedal signal, brake signal and gear signal in the driving process. The impact on the mileage of the vehicle.

Standard Continuing Mileage Test:

Choose good roads, mainly straight roads; after the vehicle starts, keep the accelerator pedal at a fixed position as much as possible, for example, the position corresponding to 25km/h on a flat road, and drive at a stable speed; Brake; stop after the battery is undervoltage, and calculate the continuation mileage from start to stop, which is called the standard continuation mileage.

Continued mileage test under complex road conditions:

The driver drives under various specified road conditions and records the driving process.

For example, under the complex road conditions in the urban area, the flow of people and vehicles is large, there are many traffic lights, and the driver needs to start and brake frequently. According to the following formula, the impact of each start, brake or stop on the mileage can be simply estimated.

$\mathrm{<span\; class="notranslate">\; \&Delta;S</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}}{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; st</span>}}}$

Among them: △S is the continuation mileage reduced by the average start of braking or parking each time, S _r is the standard continuation mileage, S _c is the continuation mileage of complex road conditions in the urban area, and n _st is the number of start braking or parking.

For example, the roads in the suburbs and countryside are of low grade, with many gravel or dirt roads, uneven road surface, high rolling resistance and low vehicle speed, so the proportion of wind resistance is low. few. According to the following formula, the impact of bad roads on mileage can be estimated, mainly considering the energy consumed by road resistance and vehicle speed changes, ignoring the impact of wind resistance, so the impact of bad roads on mileage is expressed as a percentage,

$\mathrm{<span\; class="notranslate">\; \&Delta;\&epsiv;</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; u</span>}}}{{\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; 100</span>}<span\; class="notranslate">\; \%</span>$

Among them: △ε is the proportion of the continuation mileage reduced by driving on bad roads, S _r is the standard continuation mileage, _Su is the continuation mileage on bad roads.

For example, the gear position has an important impact on the mileage. Some current electric vehicles are equipped with mechanical transmissions, usually with 2-3 gear positions, and the speed of each gear is different. Take the current common electric microcar with two gears as an example, the first gear has the lowest speed, usually the maximum speed is 20-25km/h, and the second gear has a maximum speed of about 45-60km/h. The higher the speed, the shorter the mileage. Fix the gears in different gears and test the mileage of the continuation, so as to examine the specific impact of the gear on the mileage of the continuation.

The ambient temperature and measuring point temperature test module, for specific road conditions, performs temperature rise performance analysis according to the ambient temperature and measuring point temperature. Specific road conditions are specific road conditions such as flat roads, slopes, and frequent starts.

The battery discharge capacity analysis module calculates the actual discharge capacity of the battery according to the change curve of current and voltage, and analyzes the actual performance of the battery.

The driving condition analysis module is used to analyze and calculate the battery power, motor operating point and motor efficiency, and use the vehicle driving equation to estimate the current road conditions.

Determine the working state of each component and deduce the road state according to the test signal, the process is as follows:

Calculate battery power:

P _bat = U _bat I _bat

Among them: P _bat is the battery power, U _bat is the battery voltage, and I _bat is the battery current.

Determine the operating point of the motor:

According to the battery current, that is, the operating current of the motor and the motor speed n _m , check the motor operating characteristic diagram to determine the motor operating point, and obtain the motor torque T _m and motor efficiency η _m .

Calculate vehicle speed, vehicle acceleration, gradient, vehicle driving force:

u _a ＝0.3768n _r r

$\mathrm{<span\; class="notranslate">\; a</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; du</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}}{\mathrm{<span\; class="notranslate">\; dt</span>}}<span\; class="notranslate">\; \&ap;</span>\frac{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&Delta;t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; \&Delta;t</span>}}$

$\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; arcsin</span>}<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; a</span>}}{\mathrm{<span\; class="notranslate">\; g</span>}}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}\mathrm{<span\; class="notranslate">\; i\&eta;</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}$

Among them: u _a is the vehicle speed, n _r is the wheel speed, the wheel speed n _r is proportional to the motor speed n _m , the proportional coefficient is determined by the speed ratio i of the vehicle's transmission, η is the transmission efficiency, r is the rolling radius of the wheel, and t is △t is the time interval of vehicle speed collection, and F _r is the driving force of the vehicle.

Analyze the vehicle travel equation:

${\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; fmg</span>}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}\mathrm{<span\; class="notranslate">\; A</span>}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 21.15</span>}}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; mg</span>}\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; ma</span>}$

Among them: F _r is the driving force of the vehicle, f is the rolling resistance coefficient of the road, m is the weight of the whole vehicle, including the weight of the driver, C _d is the drag coefficient, and A is the windward area.

In this formula, the vehicle weight m can be measured; the drag coefficient C _d and the windward area A are determined by the vehicle type; only the road rolling resistance coefficient is unknown, so this formula can be used to calculate the road rolling resistance coefficient.

For some models, the drag coefficient C _d is not provided, and the drag coefficient C _d can be obtained by testing on a straight and good road. The method is as follows:

1) Test the road rolling resistance coefficient

Choose a straight and good road surface, the vehicle is in a low-speed and stable running state, the vehicle speed is limited to below 5km/h, and the wind resistance is ignored, the driving equation is simplified as

F _r =fmg

Using this formula, the road rolling resistance coefficient f can be calculated.

2) Calculate the drag coefficient

Running stably at high speed on flat roads, the driving equation is simplified as

${\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; fmg</span>}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}\mathrm{<span\; class="notranslate">\; A</span>}{{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 21.15</span>}}$

This formula can be used to calculate the drag coefficient.

Test process of the present invention is as shown in Figure 2, and concrete steps are:

1) The signal acquisition mechanism is connected with the sensor group;

2) Initialize the signal acquisition mechanism;

3) Start the signal acquisition mechanism to collect data;

4) The signal analysis system analyzes the data collected by the signal collection mechanism and outputs the test results.

The signal analysis system can be set on an independent host computer, which can choose to connect with the signal acquisition mechanism during the test process, analyze the signal while collecting the signal, or choose to connect with the signal acquisition mechanism after the test is over. Institutional connectivity for one-time analysis of all acquired signals.

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 (7)

1. electric motor car driving process wireless test system, is characterized in that: described test macro includes sensor group, wireless communication unit, signals collecting mechanism and Signal Analysis System;

Sensor group, is arranged in electric motor car to be measured, gathers the raw data in electric motor car driving process to be measured;

Wireless communication unit, original data transmissions sensor group collected is to signals collecting mechanism;

Signals collecting mechanism, for the raw data that receiving sensor group collects, carries out data processing to raw data, and stores the data after process and show;

Signal Analysis System, the data that Received signal strength collecting mechanism sends, and analyzing and processing is carried out to data, output test result;

Described signals collecting mechanism includes signals collecting initialization module, and signals collecting initialization module is used for arranging collecting sensor signal passage, frequency acquisition, stored parameter and vehicle parameter; Vehicle parameter includes vehicle wheel roll radius, motor umber of pulse, wheel umber of pulse weekly weekly;

Described sensor group includes voltage sensor, current sensor, motor speed sensor, wheel speed sensor, environment temperature sensor, measuring point temperature sensor, equivalent acceleration transducer and driver behavior signal transducer; Driver behavior signal transducer includes accelerator pedal signal transducer, brake signal sensor and shift signal sensor.

2. electric motor car driving process wireless test system as claimed in claim 1, it is characterized in that: described Signal Analysis System includes the real-time computing module of road grade, its gradient computing formula is:

$\mathrm{\&theta;}=\arcsin \left(\frac{a_e-a}{g}\right)$

Wherein: θ is the angle of gradient, a _efor equivalent acceleration, i.e. acceleration transducer output valve, a is vehicle acceleration, and g is acceleration of gravity.

3. electric motor car driving process wireless test system as claimed in claim 1, it is characterized in that: described Signal Analysis System includes transmission state monitoring modular, for monitoring in gearshift procedure, motor speed and the continuous Rapid Variable Design of transmission gear ratio, ratio of gear is calculated according to motor speed and vehicle wheel rotational speed, according to speed ratio change and the monitoring of motor operating point transmission performance, duty and failure message, calculate abrasion condition and ride comfort, motor operating point includes current signal and tach signal.

4. electric motor car driving process wireless test system as claimed in claim 1, it is characterized in that: described Signal Analysis System includes driving analysis module, according to accelerator pedal signal, brake signal and shift signal in driving procedure, analytical calculation driving habits is on the impact of vehicle mileages of continuation.

5. electric motor car driving process wireless test system as claimed in claim 1, it is characterized in that: described Signal Analysis System includes environment temperature and measuring point temperature test module, for specific road conditions, environmentally temperature and measuring point temperature, carry out temperature rise model analysis.

6. electric motor car driving process wireless test system as claimed in claim 1, it is characterized in that: described Signal Analysis System includes discharge capacity of the cell analysis module, calculate the actual discharge capacity of battery according to the change curve of electric current and voltage, analyze the actual usability of battery.

7. electric motor car driving process wireless test system as claimed in claim 1, it is characterized in that: described Signal Analysis System includes driving cycle analysis module, for the analytical calculation power of battery, motor operating point and electric efficiency, and utilize vehicle equation formula, estimation present road situation.