CN116818367A - Improved high-speed PID chassis dynamometer method - Google Patents
Improved high-speed PID chassis dynamometer method Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M17/00—Testing of vehicles
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- G01M17/0072—Wheeled or endless-tracked vehicles the wheels of the vehicle co-operating with rotatable rolls
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
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Abstract
The invention discloses an improved high-speed PID chassis dynamometer method, which is characterized in that a constant-speed PID algorithm is processed, one section of PID is divided into two sections of complementary PID algorithm to control, when the force of the first PID control reaches the peak value, a second set of PID algorithm is started to perform reverse regulation, and then the oscillation generated by the two sets of PID is counteracted, so that the aim of only one regulation peak value without subsequent oscillation regulation is finally achieved on the premise of ensuring the control response speed. The invention adopts PID control algorithm to obviously improve the constant speed control speed of the chassis dynamometer, the rotating speed of the roller can be quickly stabilized, the variable load sliding control precision is improved, the engine power test precision is improved, and the test efficiency of the detection station is improved. In addition, the PID algorithm can reduce the frequency of constant-speed adjusting oscillation adjustment, reduce the damage of the vehicle engine and reduce the abrasion of the tire.
Description
Technical Field
The invention relates to the technical field of automobiles, in particular to an improved high-speed PID chassis dynamometer method.
Background
1 basic structure of automobile chassis dynamometer test bed
The detection of the output power or traction of the drive wheel is known as chassis dynamometer. The test bed is carried out on a roller test bed, and is generally called a chassis dynamometer. The force measuring test bed uses a roller as a movable road surface, and uses a loading device to simulate the running condition of an automobile and measure the output driving power, the resistance of a transmission system, the fuel consumption, the exhaust emission and the like of the driving wheel of the automobile under various speeds. At present, a force measuring test bed is adopted by most automobile detection stations. The structure mainly comprises a roller device, a loading device, a measuring device, an embedded board card, an industrial personal computer and the like.
(1) Roller device
The rollers for supporting the two driving wheels of the automobile are of double-roller structures. The drum is typically made of steel material. The surface of the roller is mainly in a plurality of forms such as smooth, knurled or coated. Currently smooth rollers are the most common. Because of the low coefficient of friction of smooth roller surfaces, a layer of paint is applied to the roller surfaces in order to reliably contact the roller with the drive wheels of the vehicle and transmit drive power.
The diameter of the roller is commonly used to be 217mm and 350mm, and the specification of the roller is related to the speed of the tested vehicle. According to the related data, the rolling resistance of the tire can reach 20% of the transmission power at a higher test vehicle speed. At the same vehicle speed, the smaller the diameter of the roller, the higher the rotating speed of the roller, the more serious the heating abrasion of the tire is caused, and the tire surface reaches the critical temperature, so that the tire is damaged. Therefore, when the test vehicle speed reaches 200km/h, the diameter of the roller should not be less than 350mm.
(2) Loading device
When the automobile runs on the road, the automobile is subjected to the resistance of an automobile transmission system, the rolling resistance of wheels, the air resistance, the acceleration resistance and the like. When the automobile is tested on the test bed, the resistance of the automobile transmission system, the resistance of the test bed transmission mechanism, the contact resistance between the wheels and the roller and the like are all the resistance. The sum of the two is unequal, and the former is larger than the latter. Thus, a loading device is needed, so that the stress condition of the automobile on the test bed is the same as the driving stress on the road. Most of chassis dynamometers in the market at present adopt an electric vortex dynamometer as a loading device, and the electric vortex dynamometer has the advantages of high measurement precision, simple and reliable control mode and the like, and can bear higher rotating speed. The electric vortex dynamometer mainly comprises a stator and a rotor. An exciting coil is arranged around the rotor, the shaft of the rotor is connected with the driving roller of the test bed, and the gear-shaped rotor disc rotates in the exciting coil. When the exciting coil is electrified with direct current, a magnetic field is generated, at the moment, eddy current is generated in the high-speed rotating gear disc-shaped rotor, the eddy current can cause a certain resisting moment on the rotating roller, and a large amount of heat is generated in the rotor. By the principle, the electric vortex dynamometer absorbs the power output by the driving wheel of the automobile, converts the power into heat and discharges the heat, and loads the roller. The electric vortex dynamometer needs a set of corresponding high-speed control board cards to accurately control the loading force and the absorbed power generated by the electric vortex dynamometer.
(3) Measuring device
The measuring device comprises a force measuring device and a speed measuring device. Because the eddy current dynamometer can not directly measure the output power of the driving wheel of the automobile, the eddy current dynamometer needs to measure the rotating speed and torque when the roller moves or the automobile speed and traction when the roller moves equivalently, and then the output power value is converted into the output power value through a formula, so the dynamometer test bed needs to be provided with a dynamometer and a speed measuring device. The test bed needs to accurately measure the speed of the automobile when testing the detection items such as the acceleration performance, the sliding performance, the fuel consumption and the like of the automobile.
(1) Force measuring device
The force transducer is connected to the stator of the eddy current dynamometer through a lever arm with a certain length, and as the stator can swing, the stator of the dynamometer applies braking action to the rotor of the dynamometer and simultaneously receives reactive moment with equal magnitude and opposite direction, the moment can act on the force transducer reversely, and tangential traction force on the driving wheel of the automobile can be measured after conversion. The control board card collects the data of the force sensor and converts the data into the traction force of the automobile.
(2) Speed measuring device
At present, a grating encoder is widely adopted for vehicle speed measurement, and has the advantages of high measurement accuracy, low cost, simplicity in installation and the like. The grating encoder is arranged on the roller shaft, and the rotating speed of the grating encoder is the same as that of the roller. Depending on the type of the grating encoder, one revolution of the grating encoder generates 1000, 2000, 5000 and 10000 pulses, and the higher the pulse number is, the more accurate the measured rotation speed is. The control board card collects the pulse signals output by the grating encoder and converts the pulse signals into the rotating speed of the roller. The driving wheel is closely contacted with the surface of the roller, and the linear speed of the surface of the roller is the running speed of the automobile. The unit is KM/H
(3) The electric vortex dynamometer can not directly measure the output power of the automobile, but calculates the output power according to the measured traction and the speed of the automobile, and the calculation formula is as follows:
P＝FV+P0
wherein P is the output power of the automobile, F is the traction force, V is the running speed of the automobile, and P0 is the parasitic power of the platform body at the speed.
(4) Auxiliary device
(1) Lifting device
Because the rollers can rotate freely, once the power wheels of the automobile are arranged between the main roller and the auxiliary roller, the automobile cannot run out under the power of the automobile. In order to facilitate the tested vehicle to drive in and out of the chassis dynamometer test bed, a lifting device is arranged between the main roller and the auxiliary roller. The lifting device has three types of pneumatic, hydraulic and electric, and the pneumatic lifting device is used as a common lifting device.
(2) Cold air device
The general chassis dynamometer test bench is provided with a movable cold air device facing the radiator in front of the automobile so as to strengthen cooling of the engine during automobile detection.
(5) Embedded control board card
The power-speed-force curves for different vehicles are greatly different, and the power ranges to be tested are different. In order to accurately control the resistance moment output by the electric vortex machine in real time, a high-speed control board card is needed. The high-speed embedded ARM processor is adopted to output a high-speed PWM signal to accurately control the exciting coil current of the eddy current machine. And the PWM duty ratio is adjusted in real time according to the collected force and the vehicle speed so as to dynamically scan the corresponding output power of the automobile under various speeds and forces. The PID control mode is adopted.
(5) Industrial computer console
The final purpose of the dynamometer is to test various power performance indexes of the automobile, and a set of testing flow conforming to national standards is needed, so that an industrial personal computer is needed to run a set of testing software to guide testers to finish the vehicle testing work in a standardized way.
Working principle of drum-type chassis dynamometer test bed:
the detection principle of the output power of the driving wheel is illustrated by taking an eddy current chassis dynamometer test bed as an example.
When in power measurement, the driving wheels of the automobile are arranged between the main roller and the auxiliary roller, the lifter descends, and the driving wheels of the automobile drive the rollers to rotate. The rotor is connected with the driving roller of the test bed, and then the rotor rotates. And the floating stator coaxial with the rotor is provided with an exciting winding, and when no current passes through the exciting winding, the rotor is not subjected to the action of a control torque. When the exciting winding passes through the direct current, a magnetic field is generated, and the rotor cuts magnetic force lines to induce eddy currents. The interaction between the eddy current and the magnetic field of the exciting coil makes the rotation of the rotor receive a certain braking torque. When the driving wheel of the automobile drives the rotor to rotate through the roller, the eddy current braking torque is overcome and energy is consumed. The intensity of the magnetic field and the electric vortex can be changed by adjusting the current of the exciting coil, namely the duty ratio of the PWM signal output by the control board card, so that the load of the driving wheel is changed. When the roller of the dynamometer stably rotates and a certain current is applied to the exciting coil, the braking torque which acts on the roller is equal to the driving torque of the driving wheel to the roller. According to the principle of acting force and reaction force, the magnitude of the moment of swinging the dynamometer stator around the main shaft is equal to the braking torque of the dynamometer stator.
Thus, as long as the electromagnetic torque received by the stator is measured, the driving torque of the driving wheel to the drum can be obtained. The electromagnetic torque received by the stator is measured by a length of force lever mounted to the dynamometer stator housing and a drive force sensor mounted below the end of the force lever. During power measurement, the electromagnetic torque acting on the stator enables the floating shell to swing around the main shaft, so that the force measuring lever is driven to act on the sensor, and an output electric signal is collected by the embedded board card. Obviously, the product of the force and the length of the lever is the value of the electromagnetic torque applied to the stator, which is the driving torque of the driving wheel to the drum.
When the rotor rotates under the drive of the roller, the rotor shaft is provided with the grating encoder, and the encoder outputs AB phase pulse signals representing the rotating speed and the rotating direction in the rotating process of the roller, and the AB phase pulse signals are collected by the main control board card, so that the rotating speed signals of the roller can be obtained. After the two signals are simultaneously input into a computer system for processing and calculation, the measured values of chassis output power (kW), driving force (N) and vehicle speed (km/h) can be displayed. The relevant calculation method is as follows:
P＝F*V
p=eddy current machine absorption power=drive wheel output power, f=torque force detected by sensor, v=drum rotation speed detected by encoder
By changing the load of the eddy current dynamometer, various resistances of the automobile running on a road can be simulated, so that the output power and the driving force of the automobile on the driving wheels at various speeds can be measured. However, in actual testing, the test of the output power and the driving force of the chassis of the automobile corresponding to the maximum power point and the maximum torque point of the steady-state rotating speed of the engine of the automobile is most used, because the dynamic property of the automobile and the engine and the working performance of the chassis can be evaluated by using the output power and the driving force.
At present, a real-time PID (proportion integration differentiation) regulation scheme is generally adopted for the chassis dynamometer, an MCU (micro control unit) is utilized for collecting values of a force sensor and a speed sensor and controlling output force of the eddy current machine in real time, and PID control is divided into three control modes including a constant force mode, a constant speed mode and a constant power mode.
Constant force mode: the embedded control board card dynamically adjusts the current of the eddy current machine through PID, so that the value collected by the force sensor is kept stable, and the upper computer scans the output power of the automobile engine under different driving forces by continuously changing the constant force target value. After the upper computer is required to change the constant force target value each time, the value acquired by the force sensor needs to reach the target value and be stabilized within the national standard required time.
Constant speed mode: the embedded control board card dynamically adjusts the current of the eddy current machine through PID, so that the speed of the vehicle collected by the encoder is kept stable,
the upper computer changes a constant speed target value every 800ms, the scanning range is 70 KM/H-56 KM/H, the scanning interval is 1KM/H, the speed within 800ms is required to reach the target value and be stabilized, and then the upper computer calculates the output power of the automobile according to the force and the speed.
Constant power mode: the embedded control board card dynamically adjusts the current of the eddy current machine through PID, the output power of the automobile is maintained stable, and the mode can finally test the maximum power output by the automobile.
The prior art has the defects that:
the PID regulation algorithm adopted by the prior chassis dynamometer can only meet the basic requirement of PID regulation, has low requirements on control precision and control speed, and results caused by the PID regulation algorithm are as follows:
in the whole process of constant power control switching in variable load sliding, the speed and force are not completely stabilized, so that the final control standard time and the theoretical calculation time have larger difference, and the difference for different platforms is larger.
In the whole process of constant speed control in power scanning, the speed is not stabilized within the specified response time of 800ms, and the platform body has inertial acceleration, so that the scanned power is not real, and the measured maximum power of the engine has a large error.
Disclosure of Invention
The invention aims to provide an improved high-speed PID chassis dynamometer method for solving the problems in the background technology.
In order to achieve the above purpose, the present invention provides the following technical solutions:
in a dynamic diagram of common constant speed PID control, each time the target speed is switched, the target speed is switched at the point A, the target speed is reached for the first time at the point B, but acceleration still exists at the moment, the speed is not stable, and the speed is not initially stabilized to the target value until the point C; the method comprises the following steps:
step 1, fitting a current-force algorithm and an inertia-speed algorithm when actually testing data:
F＝A*sqrt(E*V 2 *PWM*U/(R+XR)) (1)
wherein A is the coefficient of performance of the electric vortex machine, E is the pole number of the electric vortex machine, V is the rotating speed of the roller, PWM is the duty ratio of a control signal, U driving voltage is R is the DC internal resistance of the electric vortex machine, XR is the AC equivalent internal resistance of a coil, and F outputs force of the electric vortex machine;
(F+f-F 0 )t＝MV 1 -MV 2 (2)
m=stage inertia, V1, v2=stage start and end speeds, t=force duration, f=stage friction resistance, f0=power;
calculating PWM values required to be applied to the vortex machine for adjusting the speed from 70KM/H to 65KM/H in 800ms according to the two formulas;
step 2, compressing the adjustment time between AB;
and 3, trowelling the oscillation time between BC points.
As a further technical scheme of the invention: the step 2 specifically comprises the following steps: during the period between AB, the PID system will apply an overshoot force to pull the speed back quickly to near the target value, where the differential adjustment is limited to control the amplitude due to the need to find the maximum value of the overshoot force, and the maximum force is determined in conjunction with equation (1), ultimately limiting the time between AB to within 600 ms.
As a further technical scheme of the invention: the step 3 specifically comprises the following steps: in the period of time between BC points, the PID system can repeatedly oscillate to find the output force of the engine, the duration is longer because of the need of oscillating adjustment for multiple times, the system speed and force cannot be stabilized, the test software can always take unstable values when taking values, so that the test result error is larger, and the PID algorithm is processed to be fast and stable, as follows:
PID＝∫ 0 t1 (Kp*Ek[9]+Ki*Sk+Kd*Dk)+∫ t1 t2 (Kp*Ek[9]+Ki*Sk+Kd*Dk)。
as a further technical scheme of the invention: in PID chassis dynamometer, a gravity sensor is used for collecting loading force generated by an eddy current dynamometer:
as a further technical scheme of the invention: in PID chassis dynamometer, a grating encoder is used to collect the drum rotation speed.
As a further technical scheme of the invention: in PID chassis dynamometer, the control panel card divide into main control panel and IGBT drive plate, and main control panel part uses STM32F407 high-speed ARM microprocessor to realize gravity acquisition, speed acquisition, net gape serial communication and high-speed PID control and output PWM signal.
As a further technical scheme of the invention: and the IGBT driving plate integrates 220V alternating current into 300V direct current and outputs the 300V direct current to the electric vortex dynamometer through the high-voltage IGBT tube, and PWM signals output by the main control panel control the action of the IGBT of the driving plate so as to control the electric vortex dynamometer.
Compared with the prior art, the invention has the beneficial effects that:
the invention adopts PID control algorithm to obviously improve the constant speed control speed of the chassis dynamometer, the rotating speed of the roller can be quickly stabilized, the variable load sliding control precision is improved, the engine power test precision is improved, and the test efficiency of the detection station is improved. In addition, the PID algorithm can reduce the frequency of constant-speed adjusting oscillation adjustment, reduce the damage of the vehicle engine and reduce the abrasion of the tire.
Drawings
FIG. 1 is a dynamic diagram of a conventional constant speed PID control;
FIG. 2 is a dynamic diagram of the control effect of the present invention;
fig. 3 is a schematic diagram of the present invention.
Detailed Description
The following will clearly and completely describe the technical solutions in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1-3, an improved high-speed PID chassis dynamometer method is provided, wherein the adopted chassis dynamometer structure is identical to that of a traditional chassis dynamometer, an electric vortex dynamometer and a double-roller dynamometer table body are used, loading force generated by the electric vortex dynamometer is collected by a gravity sensor, and the rotation speed of a roller is collected by a grating encoder. The control panel card is divided into a main control panel and an IGBT driving board, and the main control panel part mainly uses an STM32F407 high-speed ARM microprocessor to realize gravity acquisition, speed acquisition, network port serial port communication and high-speed PID control and output PWM signals. The IGBT driving plate mainly integrates 220V alternating current into 300V direct current and outputs the 300V direct current to the electric vortex dynamometer through the high-voltage IGBT tube, and PWM signals output by the main control panel control the IGBT action of the driving plate so as to control the electric vortex dynamometer. In the process of programming a control program for an ARM microprocessor of a main board, the automobile inspection site is continuously tested and a PID control algorithm is improved. The following innovations are finally produced:
(1) The invention adopts the communication mode of the Ethernet port:
the chassis dynamometer on the traditional market basically uses serial ports to communicate with an upper computer, the communication mode is simple and stable, but the safety is poor, the communication speed is relatively low, the technology is old and aged, the technology is very easy to crack from a hardware level, and the anti-interference performance is poor during long-distance communication. Based on the consideration of everything interconnection, ethernet communication is introduced, so that the safety of a communication protocol and the communication speed bandwidth can be greatly improved. The high-level protocol frameworks such as firmware upgrading maintenance, parameter upgrading maintenance and the like are added, so that the chassis dynamometer is more convenient and faster to maintain and upgrade. Meanwhile, the Ethernet communication can allow after-sales service personnel to remotely debug the board card function, and real-time and timely technical service is provided for clients.
FIG. 1 is a dynamic diagram of a conventional constant speed PID control, each time the target speed is switched, a force is adjusted as shown in the above diagram; the target speed is switched at the point A, the target speed is reached for the first time at the point B, however, acceleration still exists at the moment, the speed is not stable, and the speed is not initially stabilized to the target value until the point C. The PID algorithm has two problems of slow control speed and small oscillation after the speed is stable. The technical scheme is mainly improved from three directions, 1, the adjustment time before the point A is reduced, 2, the adjustment time between the compression AB and the screeding BC is performed, and 3, the oscillation time between the points BC is smoothed.
(1) The adjustment time before the point a is reduced.
For the eddy current chassis dynamometer, the PID system needs to test the inertia of the platform body in the period before the point A, and the relation of the current-ratio of the eddy current machine is compared. The next control phase is prepared by applying a continuously varying current to the electric vortex machine and monitoring the speed-force variation to derive the current-force-speed relationship. By means of the actual test data, a current-force algorithm and inertia-speed algorithm are fitted here, as follows
F＝A*sqrt(E*V 2 *PWM*U/(R+XR)) (1)
A is the coefficient of performance of the electric vortex machine, E is the pole number of the electric vortex machine, V is the rotating speed of the roller, PWM is the duty ratio of a control signal, U is the driving voltage, R is the direct current internal resistance of the electric vortex machine, XR is the coil alternating current equivalent internal resistance, and F is the output force of the electric vortex machine.
(F+f-F 0 )t＝MV 1 -MV 2 (2)
M=stage inertia, V1, v2=stage start and end speeds, t=force duration, f=stage friction resistance, f0=power
The PWM value required to be applied to the vortex machine for adjusting the speed from 70KM/H to 65KM/H in 800ms can be calculated by the formula 1 and the formula 2, so that the time before the point A can be minimized.
(2) Adjustment time between compression AB
During this time between AB, the PID system will apply a very large overshoot force to pull the speed back quickly to near the target value, where the differential adjustment is limited to control the amplitude since it is required to find the maximum value, and the maximum force is determined in conjunction with equation 1 above, eventually limiting the time between AB to within 600 ms.
(3) Smoothing the oscillation time between BC points
In the period of time between BC points, the PID system can repeatedly oscillate to find the output force of the engine, the duration is longer because of the need of oscillating adjustment for multiple times, the system speed and force cannot be stabilized, the test software can always take unstable values when taking values, so that the test result error is larger, and the PID algorithm is processed to be fast and stable, as follows:
PID＝∫ 0 t1 (Kp*Ek[9]+Ki*Sk+Kd*Dk)+∫ t1 t2 (Kp*Ek[9]+Ki*Sk+Kd*Dk)；
when the constant speed control is carried out on the dynamometer, the inertia of the platform body causes relatively large hysteresis in the speed response of the dynamometer, so that relatively large overshoot is easy to occur in the output force in the constant speed control high-speed PID adjustment process, the overshoot force can cause tire abrasion and engine gear damage, in order to reduce the damage, the constant speed PID algorithm is processed to be divided into two sections of complementary PID algorithm for control, when the force of the first PID control reaches the peak value, the second PID algorithm is started for reverse adjustment, and then oscillation generated by the two PID algorithms is mutually offset, and finally, the aim that only one adjustment peak value does not have subsequent oscillation adjustment is achieved on the premise of ensuring the control response speed, and the final control effect is shown in figure 2.
By adopting the PID control algorithm, the constant speed control speed of the chassis dynamometer can be obviously improved, the rotating speed of the roller can be quickly stabilized, the variable load sliding control precision is improved, the engine power test precision is improved, and the test efficiency of the detection station is improved. In addition, the PID algorithm can reduce the frequency of constant-speed adjusting oscillation adjustment, reduce the damage of the vehicle engine and reduce the abrasion of the tire.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Furthermore, it should be understood that although the present disclosure describes embodiments, not every embodiment is provided with a separate embodiment, and that this description is provided for clarity only, and that the disclosure is not limited to the embodiments described in detail below, and that the embodiments described in the examples may be combined as appropriate to form other embodiments that will be apparent to those skilled in the art.
Claims (7)
1. In a dynamic diagram of common constant speed PID control, each time the target speed is switched, the target speed is switched at the point A, the target speed is reached for the first time at the point B, but acceleration still exists at the moment, the speed is not stable, and the speed is not initially stabilized to the target value until the point C; the method is characterized by comprising the following steps of:
step 1, fitting a current-force algorithm and an inertia-speed algorithm when actually testing data:
F＝A*sqrt(E*V 2 *PWM*U/(R+XR)) (1)
wherein A is the coefficient of performance of the electric vortex machine, E is the pole number of the electric vortex machine, V is the rotating speed of the roller, PWM is the duty ratio of a control signal, U driving voltage is R is the DC internal resistance of the electric vortex machine, XR is the AC equivalent internal resistance of a coil, and F outputs force of the electric vortex machine;
(F+f-F 0 )t＝MV 1 -MV 2(2)
m=stage inertia, V1, v2=stage start and end speeds, t=force duration, f=stage friction resistance, f0=power;
calculating PWM values required to be applied to the vortex machine for adjusting the speed from 70KM/H to 65KM/H in 800ms according to the two formulas;
step 2, compressing the adjustment time between AB;
and 3, trowelling the oscillation time between BC points.
2. The improved high-speed PID chassis dynamometer method according to claim 1, wherein the step 2 is specifically: during the period between AB, the PID system will apply an overshoot force to pull the speed back quickly to near the target value, where the differential adjustment is limited to control the amplitude due to the need to find the maximum value of the overshoot force, and the maximum force is determined in conjunction with equation (1), ultimately limiting the time between AB to within 600 ms.
3. The improved high-speed PID chassis dynamometer method according to claim 1, wherein the step 3 is specifically: in the period of time between BC points, the PID system can repeatedly oscillate to find the output force of the engine, the duration is longer because of the need of oscillating adjustment for multiple times, the system speed and force cannot be stabilized, the test software can always take unstable values when taking values, so that the test result error is larger, and the PID algorithm is processed to be fast and stable, as follows:
PID＝∫ 0 t1 (Kp*Ek[9]+Ki*Sk+Kd*Dk)+∫ t1 t2 (Kp*Ek[9]+Ki*Sk+Kd*Dk)。
4. the improved high-speed PID chassis dynamometer of claim 1, wherein the gravity sensor is used to collect the loading force generated by the eddy current dynamometer during PID chassis dynamometer.
5. The improved high-speed PID chassis dynamometer method of claim 1, wherein in PID chassis dynamometer, a grating encoder is used to collect the rotational speed of the drum.
6. The improved high-speed PID chassis dynamometer method according to claim 1, wherein in PID chassis dynamometer, a control board card is divided into a main control board and an IGBT driving board, and the main control board part uses an STM32F407 high-speed ARM microprocessor to realize gravity acquisition, speed acquisition, network port serial port communication and high-speed PID control and output PWM signals.
7. The improved high-speed PID chassis dynamometer method according to claim 6, wherein the IGBT driving plate integrates 220V alternating current into 300V direct current and outputs the 300V direct current to the electric vortex dynamometer through the high-voltage IGBT tube, and PWM signals output by the main control plate control the action of the IGBT of the driving plate so as to control the electric vortex dynamometer.
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