Summary of the invention
The purpose of this invention is to provide a kind of kinematic train mechanical loss and fixing method for measuring rotary inertia, need not artificial the completion, and Measuring Time is short, efficiency of measurement is high, measuring accuracy is high.
To achieve these goals; The invention provides a kind of kinematic train mechanical loss and fixing method for measuring rotary inertia; Comprise the steps: the measurement parameter of setting measurement mechanical loss, comprise speed setting value, stable state stand-by period and the Measuring Time corresponding with said speed setting value; The control motor moves with said speed setting value; When said motor reaches said setting speed setting value; Waiting for that the stable state corresponding with said setting speed setting value is after the stand-by period; Collect the number of scan period and the actual torque value of each scan period, the duration of collection is and the corresponding Measuring Time of said setting speed setting value; The actual torque value of all scan periods is added up, and the accumulated value of actual torque is the mechanical loss corresponding with said speed setting value with the merchant of the number of said scan period.
In one embodiment of the invention, the speed setting value of setting can be for a plurality of, and each speed setting value is provided with corresponding stable state stand-by period and Measuring Time.
In another embodiment of the present invention; A plurality of speed setting values of said setting are all interval speed setting values of full speed degree; Then, said method also comprises: each speed setting value and corresponding mechanical loss are carried out related, obtain the interval mechanical loss curve of full speed degree.
In another embodiment of the present invention; Said method also comprises: the measurement parameter of setting measurement moment of inertia; Comprise the minimum speed value of maximum speed value, the measurement of stand-by period of measuring between number of times, the up-down speed, measurement, fixing acceleration setting value and the stand-by period between twice measurement; The PLC controller is confirmed single measurement speed setting value curve according to the stand-by period between maximum speed value, minimum speed value, acceleration setting value and twice measurement set, confirms general speed setting value curve according to the measurement number of times of setting, the stand-by period between the up-down speed and the single measurement speed setting value curve of confirming; The control motor is with said general speed setting value curve motion; In motor operation course; Monitor the instantaneous velocity setting value of motor and the instantaneous velocity value of feedback corresponding in real time with said instantaneous velocity setting value; When the difference of said instantaneous velocity setting value and said instantaneous velocity value of feedback is not more than 10 rev/mins; Collect number, the actual torque value of each scan period and the angular acceleration of scan period, and search the mechanical loss value corresponding with said instantaneous velocity setting value according to the interval mechanical loss curve of said full speed degree; Calculate the moment of inertia of each scan period according to actual torque value, angular acceleration and the mechanical loss value of said each scan period; The moment of inertia of all scan periods added up obtains the moment of inertia accumulated value, and the merchant of the number of said moment of inertia accumulated value and said scan period is the moment of inertia mean value between measurement zone.
Compared with prior art, kinematic train mechanical loss of the present invention and fixedly the advantage of moment of inertia method be:
1.PLC (Programmable Logic Controller) controller passes through the Frequency Converter Control motor rotation based on preset parameters; Automatically measurement transmission system mechanical loss and fixedly rotary inertia; Can measure multiple devices simultaneously, Measuring Time is short, and efficiency of measurement is high, certainty of measurement is high;
2. in measurement mechanical loss with fixedly adopt the output of fixed slope speed setting value in the process of moment of inertia; And the feedback speed and the difference between the setting speed that guarantee motor are within certain scope; Collection period with a few tens of milliseconds; Read measurement data fast and dense, calculate its mean value, improved the measuring accuracy of moment of inertia.。
Through following description and combine accompanying drawing, it is more clear that the present invention will become, and these accompanying drawings are used to explain embodiments of the invention.
Embodiment
With reference now to accompanying drawing, describe embodiments of the invention, the similar elements label is represented similar elements in the accompanying drawing.
In explanation kinematic train mechanical loss of the present invention with fixedly before the detailed process of moment of inertia method, explanation kinematic train mechanical loss and the fixedly measuring principle of moment of inertia method earlier.
In kinematic train, the output torque T of motor
DCan be expressed as:
T
D=T
e+T
f+T
d+T
w (1)
In the formula, T
eFor with the mechanical loss torque of velocity correlation, T
fBe the torque that the fixedly moment of inertia relevant with velocity variations needs, T
dBe the torque that the variable rotational inertia relevant with velocity variations needs, T
wBe operation torque.
When kinematic train is unloaded, the torque T that the variable rotational inertia relevant with velocity variations needs
dWith operation torque T
wBe 0, the output torque T of motor
DEqual mechanical loss torque T with velocity correlation
eThe torque T that needs with the fixedly moment of inertia relevant with velocity variations
fWith:
T
D=T
e+T
f; (2)
In the formula, the torque T that the fixedly moment of inertia relevant with velocity variations needs
fEqual fixedly moment of inertia J and angular acceleration
Product:
Can get by formula (2), (3):
Can get by formula (4):
When motor operated in constant rotational speed, angular acceleration equalled zero, promptly
Mechanical loss torque T with velocity correlation
eEqual the output torque T of motor
D, measure the output torque T of motor through frequency converter with the PLC controller
D, can obtain mechanical loss torque T with velocity correlation
e
When motor during, measure the output torque T of motor through frequency converter with the PLC controller in acceleration and deceleration
D, measure angular acceleration with the PLC controller
And the mechanical loss torque T of velocity correlation
eWhen motor operates in constant rotational speed, measure earlier, can calculate fixedly moment of inertia J according to formula (5).
Like Fig. 1, the control system of this method comprises PLC controller 200, communication network, HMI (HumanMachine Interface) 100, frequency converter 300, and the motor 400 of driving arrangement rotation.The PLC controller is connected with HMI, frequency converter respectively through communication network, and frequency converter is connected with motor.The PLC controller sends to frequency converter through communication network with the general speed setting curve, and frequency converter is through the operation of speed setting curve controlled motor.HMI is used for monitoring the running status of PLC controller, and passes through the running status of PLC controller monitoring frequency converter and motor.
Explanation kinematic train mechanical loss of the present invention and the fixedly detailed process of method for measuring rotary inertia below.
Like Fig. 3, kinematic train mechanical loss measuring method of the present invention comprises the steps:
Step S1, the measurement parameter of setting measurement mechanical loss comprises the mechanical loss measurement point, and the speed setting value of corresponding said mechanical loss measurement point, stable state stand-by period, Measuring Time;
Step S2; The PLC controller is through the speed setting value operation of Frequency Converter Control motor according to the mechanical loss measurement point of step S1 setting; When motor reaches the speed setting value corresponding with said mechanical loss measurement point; Waiting for the stable state corresponding with said mechanical loss measurement point after the stand-by period, the PLC controller is collected number and the actual torque value of each scan period (for guaranteeing measuring accuracy, the scan period is set at 20 milliseconds) of scan period; The duration of collecting is and the corresponding Measuring Time of said mechanical loss measurement point; After collecting end, the PLC controller adds up the actual torque value of all scan periods, and the number of the accumulated value of actual torque value and scan period is stored in the PLC storer;
Step S3, the PLC controller according to be stored in actual torque in the PLC storer accumulated value and the number calculating mean value of scan period, this mean value is the mechanical loss under this speed setting value, computing formula is following:
Mechanical loss=actual torque the number of accumulated value/scan period
By on can find out that this method can be measured the mechanical loss under a certain speed setting value.
Be appreciated that ground, the present invention can set other mechanical loss measurement points in step S1, and corresponding other speed setting values of setting, and obtains the mechanical loss of corresponding said other speed setting value.
In addition; The present invention also can set all interval speed setting values of full speed degree, and obtains the mechanical loss corresponding with all speed setting values, then according to trace-point method; Draw out the interval corresponding mechanical loss curve of full speed degree; Like this, in actual moving process, just can obtain and the corresponding mechanical loss value of any speed setting value.
Continue like Fig. 3, kinematic train of the present invention fixedly method for measuring rotary inertia also comprises the steps:
Step S4; The measurement parameter of setting measurement moment of inertia; Comprise the stand-by period (Tw) of measuring between number of times (n), the up-down speed, the maximum speed value (Vmax) of measurement, the minimum speed value of measuring (Vmin) and fixing acceleration setting value (a), the stand-by period (Tu) between twice measurement; The PLC controller is confirmed single measurement speed setting value curve according to the stand-by period (Tu) between maximum speed value (Vmax), minimum speed value (Vmin), acceleration setting value (a) and twice measurement set; Confirm general speed setting value curve according to the measurement number of times of setting (n), the stand-by period (Tw) between the up-down speed and the single measurement speed setting value curve of confirming, general speed setting value curve is as shown in Figure 2:
Wherein: Δ T=Δ T1=Δ T2
Step S5; The PLC controller through the Frequency Converter Control motor according to the general speed setting value curve motion that in step S4, obtains; In motor operation course; The PLC controller is monitored instantaneous velocity setting value and the instantaneous velocity value of feedback corresponding with said instantaneous velocity setting value in real time; When the difference of said instantaneous velocity setting value and said instantaneous velocity value of feedback is not more than 10 rev/mins, the PLC controller is collected number, the actual torque value T of each scan period (for guaranteeing measuring accuracy, the scan period is set at 20 milliseconds) of scan period
DAnd angular acceleration
, and search the mechanical loss value T corresponding with said instantaneous velocity setting value according to the interval corresponding mechanical loss curve of full speed degree as previously mentioned
e, the PLC controller is the actual torque value T of the number of scan period, each scan period
D, angular acceleration
And mechanical loss value T
eBe stored in the PLC storer, when the difference of said instantaneous velocity setting value and said instantaneous velocity value of feedback during greater than 10 rev/mins, measuring process is unusual, and the PLC controller stops to collect;
Step S6, the PLC controller is according to the actual torque value T that is stored in each scan period in the PLC storer
d, angular acceleration
And mechanical loss value T
eUtilize formula (5) to calculate the moment of inertia J of each scan period; Simultaneously the moment of inertia J of all scan periods is added up and obtain the moment of inertia accumulated value; Calculate the moment of inertia mean value between measurement zone according to number that is stored in the scan period in the PLC storer and moment of inertia accumulated value, computing formula is following:
The number of moment of inertia mean value=moment of inertia accumulated value/scan period
Because non-constant, the angular acceleration of mechanical friction of kinematic train
With actual torque value T
DMeasurement have error, the measured value of the moment of inertia J of each scan period possibly have small difference, therefore, the merchant of the number of moment of inertia accumulated value and scan period is the measured value of moment of inertia.
By on can find out that this method can be measured the fixedly moment of inertia under a certain speed.
Kinematic train mechanical loss of the present invention and fixedly the advantage of moment of inertia method be:
1.PLC controller through the Frequency Converter Control motor rotation, is measured transmission system mechanical loss and fixing rotary inertia based on preset parameters automatically, can measure multiple devices simultaneously, Measuring Time is short, and efficiency of measurement is high, certainty of measurement is high;
2. in measurement mechanical loss with fixedly adopt the fixing speed setting value curve of accekeration in the process of moment of inertia; The instantaneous velocity value of feedback of assurance motor and the difference between the instantaneous velocity setting value are within certain scope; Collection period with a few tens of milliseconds; Measurement data is collected on fast and dense ground, and calculating mean value has improved the measuring accuracy of moment of inertia.
More than combine most preferred embodiment invention has been described but the present invention is not limited to the embodiment of above announcement, and should contain various modification, equivalent combinations of carrying out according to essence of the present invention.