CN104022705B - The method reducing spliced servomotor torque fluctuations is compensated by reluctance force - Google Patents

Abstract

The problem that there is bigger torque fluctuations for spliced servomotor, the present invention provides a kind of method being compensated by reluctance force and reducing spliced servomotor torque fluctuations: 1, measure spliced servomotor magnetic resistance moment T suffered by during rotating a circle_c.2, the expression formula of magnetic resistance moment and position of rotation is built.3 direct-axis current values I obtaining motor_dWith quadrature axis current value I_q.4, willWith motor torque coefficientIt is divided by, it is thus achieved that with the compensation electric current of change in location.5, by I_dAnd I_qObtain the theoretical reference electric current I of motor^* _qv.By theoretical reference electric current I^* _qvWith the compensation electric current I with change in location_qrSubtract each other, it is thus achieved that actual quadrature axis reference current I^* _qAnd input PWM motor is driven.Useful technique effect: after using this method, the torque fluctuations of spliced servomotor averagely reduces by 40% than the fluctuation before using.

Description

The method reducing spliced servomotor torque fluctuations is compensated by reluctance force

Technical field

The invention belongs to electromechanical control field, particularly to the spliced servomotor of a kind of multiple stators for large-scale turntable Control method, compensates the method reducing spliced servomotor torque fluctuations specifically by reluctance force.

Background technology

Along with the development of science and technology, the size of the equipment such as lathe, radar, telescope is increasing, the turntable chi of needs Very little the most increasing.Astronomical telescope size such as foreign latest type has reached 30 to 50 meters (m).Conventional power train If system can not meet the requirement of the rotary inertia required for these equipment and mechanical stiffness according to traditional transmission design side Case, needs the torque motor diameter directly driven used to be up to more than 10m.This will bring to the processing of motor, transport The biggest trouble.

The solution using the spliced servomotor of multiple stators structure to be driven above-mentioned large-scale turntable is suggested and obtains To being widely applied.Described spliced servomotor is made up of polylith arcuate stator, every piece of stator of spliced servomotor And being all equivalent to a unit motor between the mover of spliced servomotor, whole spliced servomotor can be regarded as by many The big motor that platform unit motor is constituted.The design of electromechanical integration is used again between this spliced servomotor and large-scale turntable, can The annexation the strongest to form rigidity, thus increase substantially the dynamic response of large-scale turntable.Additionally, when spliced servo electricity The when that one piece of stator in machine breaking down, maintenance can be removed at any time, have no effect on the work of whole spliced servomotor Make.

But there is the problem that torque fluctuations is bigger in this kind of spliced servomotor.The moment ripple that spliced servomotor produces Dynamic relatively big, spliced servomotor will be caused smoothly to rotate.The reason that torque fluctuations causes has a variety of, the most main The reason wanted is exactly that this kind of spliced servomotor exists bigger Bian Duanli and Slot force, and the two may be collectively referred to as spliced servo The reluctance force of motor.

The method reducing the torque fluctuations that spliced servomotor produces at present is that the frame for movement to spliced servomotor is entered The structure optimization that row is special, reduces the reluctance force of spliced servomotor.But the method repeatability is low, and cost is high, the cycle Long.

Summary of the invention

The problem that there is bigger torque fluctuations for spliced servomotor, the present invention is provided a kind of and is compensated by reluctance force The method reducing spliced servomotor torque fluctuations.

Concrete step is as follows: compensated the method reducing spliced servomotor torque fluctuations by reluctance force, in splicing One position sensor is installed on the rotor of formula servomotor, the driving module of spliced servomotor is provided with an electricity Flow sensor, the driving module of described spliced servomotor is connected with the stator pack of spliced servomotor；Watch spliced Taking motor one digital signal processor DSP of other configuration, described digital signal processor DSP includes serial communication interface module SCI, analog-to-digital conversion module AD, Pulse width modulation module PWM and quadrature coding pulse module QEP；Wherein, numeral Analog-to-digital conversion module AD in signal processor DSP is connected with current sensor；By analog-to-digital conversion module AD by electricity The analogue value that flow sensor is exported is converted to digital quantity value；Serial communication interface module SCI in digital signal processor DSP It is connected with an industrial computer,；Pulse width modulation module PWM in digital signal processor DSP is through photo-coupler OC It is connected with the driving module of spliced servomotor, by the Pulse width modulation module PWM driving to spliced servomotor Module is controlled；Quadrature coding pulse module QEP in digital signal processor DSP is connected with position sensor, logical Cross the signal that position sensor sends by quadrature coding pulse module QEP and be converted into the mechanical angle that spliced servomotor is current φ.And according to the following steps spliced servomotor be monitored and control:

Step 1: rotate with a spliced servomotor of standard driven by motor, measure spliced servomotor in the process rotated a circle In often rotate magnetic resistance moment T suffered when 1 degree_c, obtain altogether 360 discrete magnetic resistance moment T_cValue；

Step 2: 360 the discrete magnetic resistance moment T by Fourier space, step 1 obtained by digital signal processor DSP_c Value matching and be built into the magnetic resistance moment of spliced servomotor and the linear function expression T of position of rotation_c(φ):

$T_c\left(\mathrm{\φ}\right)=\underset{1}{\overset{n}{\Σ}}{T}_{cn}\cos \left(\frac{2n\mathrm{\π}\mathrm{\φ}}{\mathrm{\τ}}\right)+T_{sn}sin\left(\frac{2n\mathrm{\π}\mathrm{\φ}}{\mathrm{\τ}}\right)$

Wherein T_cIt is the magnetic resistance moment size of motor, T_cnIt is reluctance force harmonic wave cosine term coefficient, T_snIt it is reluctance force harmonic sine term system Number, φ is the mechanical angle of spliced servomotor, and τ is the pole span of spliced servomotor；

Step 3: disconnect the connection of standard electromotor and spliced servomotor；The assembling of spliced servomotor is put to needing use to set In Bei, power to spliced servomotor and make its autorotation work；With current sensor gather in rotary work spliced The three-phase electricity flow valuve of servomotor: A phase current values i_a, B phase current values i_bWith C phase current values i_c, and it is transferred to digital signal Processor DSP.CLARKE conversion three-phase electricity flow valuve carried out successively by digital signal processor DSP and PARK vector Convert A phase current values i of Real-time Collection_a, B phase current values i_bWith C phase current values i_cIt is changed into direct-axis current value I_dAnd friendship Shaft current value I_q；

Step 4: by digital signal processor DSP by the line of the reluctance force of spliced servomotor that obtained by step 2 with position of rotation Property function expression T_c(φ) with motor torque COEFFICIENT K_tIt is divided by, it is thus achieved that with the compensation electric current I of change in location_qr:

I_qr=T_c(φ)/K_t；

Step 5: by digital signal processor DSP by control system speed ring PID direct-axis current value I to being obtained by step 3_d With quadrature axis current value I_qCarry out computing and obtain the theoretical reference electric current I of spliced servomotor^* _qv.By theoretical reference electric current I^* _qvWith The compensation electric current I with change in location obtained by step 4_qrSubtracting each other, obtained difference is referred to as actual quadrature axis reference current I^* _q, It is the electric current of the spliced servomotor of actual driving.By the Pulse width modulation module PWM in digital signal processor DSP By actual quadrature axis reference current I^* _qThe driving module of spliced servomotor it is transferred to, it is achieved to spliced through photo-coupler OC The real-time control of servomotor.

Beneficial effects of the present invention

The inventive method by being decomposed into the current component (excitation component or direct-axis component) producing magnetic field and producing by motor stator current phasor The current component (torque component or quadrature axis component) of raw torque is controlled by, respectively such that it is able to obtain comparatively ideal linear current Moment conditions.In other words, be control system electric current loop add compensate electric current mode to reduce the reluctance force of motor, from And reduce the torque fluctuations of motor, reach to improve the purpose of servosystem tracking accuracy.Control method of the present invention can be at very great Cheng Eliminate the torque fluctuations that spliced motor causes due to side-termind effect on degree, meet motor high-precision rotary.

Accompanying drawing explanation

The control flow chart of Fig. 1 present invention.

The control Principle of Process figure of Fig. 2 present invention.

The moment test philosophy figure of Fig. 3 present invention.

In the moment test process of Fig. 4 present invention, testing of electric motors rotates forward rotor force diagram.

In the moment test process of Fig. 5 present invention, testing of electric motors contra-rotating rotor force diagram.

Fig. 6 present invention realizes the hardware block diagram used.

Fig. 7 reality of the present invention test employing this method and do not use this method torque fluctuations figure.

Detailed description of the invention

For making the object, technical solutions and advantages of the present invention clearer, below in conjunction with specific embodiment, and reference Accompanying drawing, the present invention is described in more detail.

Motor actual output torque mainly includes two parts, electromagnetic torque and disturbance torque.Disturbance torque herein refers in particular to electricity The magnetic resistance moment of machine self.Assume that motor winding does not contains higher hamonic wave and motor air gap magnetic is close for sinusoidal wave situation Under, the electromagnetic torque of motor output is constant.The magnetic resistance moment of motor is the letter of the cyclic swing relevant with self structure form Number.When using vector controlled, it is linear relationship between electromagnetic torque and the quadrature axis current of motor.Owing to magnetic resistance moment is motor rotation The periodic function that indexing is put, therefore the output torque of motor will be with position of rotation and does periodically fluctuation, thus can destroy The Steady speed of motor and position tracking characteristics.Reluctance force amplitude is the biggest, and the torque fluctuations of motor is the most obvious, the speed of motor Stationarity and position tracking characteristics are the poorest.The present invention, by measuring the reluctance force of motor, is compensated electric current with position After change information, at the desired reference electric current I of electric current loop^* _qvIn deduct the compensation electric current I that current position reluctance force is corresponding_qr, just Can make electromagnetic torque that motor exports and magnetic resistance moment by etc. the most reverse rule change so that the overall moment of motor output For constant, motor servo system is made to reach the purpose of even running.

See Fig. 6, the rotor of spliced servomotor is provided with a position sensor, at spliced servomotor Driving and be provided with a current sensor in module, the driving module of described spliced servomotor is determined with spliced servomotor Subgroup is connected；At spliced servomotor one digital signal processor DSP of other configuration, described digital signal processor DSP includes serial communication interface module SCI, analog-to-digital conversion module AD, Pulse width modulation module PWM and orthogonal coding Pulse module QEP；Wherein, the analog-to-digital conversion module AD in digital signal processor DSP is connected with current sensor； The analogue value exported by current sensor by analog-to-digital conversion module AD is converted to digital quantity value；Digital signal processor DSP Interior serial communication interface module SCI and an industrial computer are connected,；Pulse width in digital signal processor DSP is adjusted Molding block PWM is connected, by Pulse width modulation module with the driving module of spliced servomotor through photo-coupler OC The driving module of spliced servomotor is controlled by PWM；Quadrature coding pulse module in digital signal processor DSP QEP is connected with position sensor, and the signal sent by position sensor by quadrature coding pulse module QEP is converted into spelling Meet the mechanical angle φ that formula servomotor is current.

As it is shown in figure 1, according to the following steps spliced servomotor be monitored and control:

Step 1: rotate with a spliced servomotor of standard driven by motor, measure spliced servomotor in the process rotated a circle In often rotate magnetic resistance moment T suffered when 1 degree_c, obtain altogether 360 discrete magnetic resistance moment T_cValue, its concrete measurement Step is as shown in Figure 3.

See Fig. 3, it is thus achieved that 360 magnetic resistance moment T_cConcretely comprising the following steps of value:

Spliced servomotor to be measured to one standard motor and one is placed on monitor station jointly；The rotor of standard electromotor is installed There is driving electric machine winding dish 1, the rotor of spliced servomotor to be measured is provided with servomotor wire spool 6, drive electricity The edge of machine wire spool 1 and one end of the first connecting line 81 are connected, the other end of the first connecting line 81 and the one of ergometer 4 End is connected, and the other end of ergometer 4 is connected with the edge of servomotor wire spool 6；One end of 3rd connecting line 83 with The edge of servomotor wire spool 6 is connected, and the other end of the 3rd connecting line 83 connects pouring weight 9.At detection edge of table Being provided with an assembly pulley (10), the 3rd connecting line 83 being connected with pouring weight 9 naturally droops after walking around assembly pulley (10).

Measure the magnetic resistance moment T of spliced servomotor_cStep as follows:

Step 1.1: in the case of tested model machine is cold, is driven spliced servomotor at the uniform velocity to rotate a circle by standard electromotor.By counting The signal that word signal processor DSP position sensor produces be converted to spliced servomotor real-time rotate forward angle, logical Cross ergometer 4 and obtain loading moment value TL rotated forward corresponding when spliced servomotor often rotates 1 °₁, obtain altogether Obtain 360 loading moment values TL rotated forward₁, as shown in Figure 4.

Step 1.2: make standard electromotor drive spliced servomotor at the uniform velocity to reversely rotate one week, the side as described in step 1.1 Method, obtains spliced servomotor and often reversely rotates loading moment value TL of reverse rotation corresponding when 1 °₂, obtain altogether 360 loading moment values TL reversely rotated₂, as shown in Figure 5.

Step 1.3: in order to remove moment of friction T_fImpact on test result, will rotate rotating forward of same angular angle value Loading moment value TL₁With loading moment value TL reversely rotated₂Take after arithmetic mean of instantaneous value with loading moment T_gDo difference, obtain magnetic Moment of resistance T_c:

$T_c=\frac{1}{2}(T_{L1}+T_{L2})-T_g$

In formula, loading moment T_gFor the pouring weight (9) moment to servomotor wire spool (6).Obtain altogether 360 magnetic resistance moments T_cValue.

Step 2: by digital signal processor DSP by Fourier space (Fourier's non-linear regression analysis) by step 1 360 the discrete magnetic resistance moment T obtained_cValue matching and be built into the magnetic resistance moment of spliced servomotor and position of rotation Linear function expression T_c(φ):

$T_c\left(\mathrm{\φ}\right)=\underset{1}{\overset{n}{\Σ}}{T}_{cn}\cos \left(\frac{2n\mathrm{\π}\mathrm{\φ}}{\mathrm{\τ}}\right)+T_{sn}sin\left(\frac{2n\mathrm{\π}\mathrm{\φ}}{\mathrm{\τ}}\right)$

Wherein T_cIt is the magnetic resistance moment size of motor, T_cnIt is reluctance force harmonic wave cosine term coefficient, T_snIt it is reluctance force harmonic sine term system Number, φ is the mechanical angle of spliced servomotor, and τ is the pole span of spliced servomotor.

Step 3: disconnect the connection of standard electromotor and spliced servomotor；The assembling of spliced servomotor is put to needs and makes Equipment in, power to spliced servomotor and make its autorotation work；Gather in rotary work with current sensor The three-phase electricity flow valuve of spliced servomotor: A phase current values i_a, B phase current values i_bWith C phase current values i_c, and it is transferred to number Word signal processor DSP.By digital signal processor DSP, three-phase electricity flow valuve is carried out successively CLARKE conversion and PARK vector is by A phase current values i of Real-time Collection_a, B phase current values i_bWith C phase current values i_cIt is changed into direct-axis current Value I_dWith quadrature axis current value I_q.Method particularly includes:

First pass around the A phase winding electric current i of the tested spliced servomotor that current sample obtains_aWith B phase winding electric current i_b, warp Cross CLARKE change obtain under rest frame by the first quadrature axis current I of measured motor_αWith the second quadrature axis current I_β:

$\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]=\frac{2}{3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\\ i_c\end{array}\right]$

By i_a+i_b+i_c=0 can obtain

$\left\{\begin{array}{c}{i}_{\mathrm{\α}}=i_a\\ i_{\mathrm{\β}}=(2i_b+i_a)/\sqrt{3}\end{array}\right.$

Secondly convert the first quadrature axis current I under rest frame through PARK_αWith the second quadrature axis current I_βIt is changed to rotational coordinates By direct-axis current I of measured motor under system_dWith quadrature axis current I_q:

$\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]=\left[\begin{array}{cc}cos\mathrm{\θ}& sin\mathrm{\θ}\\ -sin\mathrm{\θ}& cos\mathrm{\θ}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]$

Wherein θ is by the electrical angle of measured motor, and it is θ=2P Φ with the mechanical angle Φ relation of self, and wherein P is the most right of this motor Number.

Step 4: by the reluctance force of the spliced servomotor obtained by step 2 and rotated position by digital signal processor DSP The linear function expression T put_c(φ) with motor torque COEFFICIENT K_tIt is divided by, it is thus achieved that with the compensation electric current I of change in location_qr:

I_qr=T_c(φ)/K_t。

Step 5: digital signal processor DSP uses control system speed ring PID, to the direct-axis current obtained by step 3 Value I_dWith quadrature axis current value I_qCarry out computing, obtain the theoretical reference electric current I of spliced servomotor^* _qv.By Digital Signal Processing Device DSP is by theoretical reference electric current I^* _qvWith the compensation electric current I with change in location obtained by step 4_qrSubtract each other difference, obtained Difference is referred to as actual quadrature axis reference current I^* _q, this actual quadrature axis reference current I^* _qIt is the electricity of the spliced servomotor of actual driving Stream.Finally, by the Pulse width modulation module PWM in digital signal processor DSP by actual quadrature axis reference current I^* _qWarp Photo-coupler OC is transferred to the driving module of spliced servomotor, it is achieved the real-time control to spliced servomotor.

Fig. 2 is in the inventive method, the simple view of step 4 to 5: measure spliced servo electricity by electronic dynamometer The reluctance force T of machine_c(φ) after with the change information of position, will be at control system speed ring PID by digital signal processor DSP The desired reference electric current I that computing obtains^* _qvIn deduct the compensation electric current I that current position reluctance force is corresponding_qr, so that it may so that motor is defeated The electromagnetic torque that goes out and magnetic resistance moment by etc. the most reverse rule change so that the overall moment of motor output is constant, make electricity Machine servo system reaches low speed, the purpose run steadily, in high precision.

Preferably scheme is that digital signal processor DSP uses the Fourier space on more than 5 rank to magnetic resistance moment T_cBe worth into Line nonlinearity regression analysis and calculating.

Preferably scheme is that digital signal processor DSP is to A phase current values i_a, B phase current values i_bWith C phase current values i_cCurrent electrical angle θ carrying out needing to obtain spliced servomotor during PARK vector is to be obtained by functional expression θ=2P Φ Arriving, wherein, φ is the mechanical angle that spliced servomotor is current, the current mechanical angle φ of spliced servomotor be by The signal operation that digital signal processor DSP pair position sensor coaxial mounted with servomotor is gathered obtains after processing 's.Furtherly, standard electromotor is the motor of Low-torque fluctuation, and its torque fluctuations is within 5%.

Fig. 6 is the hardware block diagram that the present invention realizes using, and whole method is to realize based on high performance signal processor (DSP) 's.In the present invention, CLARK conversion, PARK conversion, speed ring PID arithmetic, electric current loop PID arithmetic are all at DSP Chip is carried out.

Fig. 7 is to use this method and do not use the torque fluctuations contrast schematic diagram of this method.Use spliced after this method watching The torque fluctuations taking motor reduces by 40% than fluctuation when being provided without this method.

Furtherly, between standard electromotor and a spliced servomotor to be measured, concrete hardware annexation sees figure 3: standard electromotor and spliced servomotor to be measured are placed on monitor station jointly.Wherein, standard electromotor includes driving motor fixed Son 2, driving electric machine winding dish 1 and driving rotor 3, drive electric machine winding dish 1 coaxially to connect with driving rotor 3 Connect, drive motor stator 2 to be arranged on the outside driving rotor 3.Spliced servomotor include servo motor stator 5, Servomotor wire spool 6 and servo motor rotor 7, servomotor wire spool 6 is coaxially connected with servo motor rotor 7, servo Motor stator 5 is arranged on the outside of servo motor rotor 7.The two ends of ergometer 4 are respectively by the first connecting line 81 and second Connecting line 82 is connected with driving the edge of electric machine winding dish 1, the edge of servomotor wire spool 6.Pouring weight 9 is by the 3rd Connecting line 83 is connected with the edge of servomotor wire spool 6.The above, the only detailed description of the invention in the present invention, But protection scope of the present invention is not limited thereto, any it is familiar with the people of this technology in the technical scope that disclosed herein, can Understand the conversion expected or replacement, all should contain within the scope of the comprising of the present invention.

Claims (6)

1. compensated the method reducing spliced servomotor torque fluctuations by reluctance force, it is characterised in that at spliced servomotor Rotor on a position sensor is installed, the driving module of spliced servomotor is provided with a current sensor； At spliced servomotor one digital signal processor DSP of other configuration, described digital signal processor DSP includes serial and leads to Letter interface module SCI, analog-to-digital conversion module AD, Pulse width modulation module PWM and quadrature coding pulse module QEP； Wherein, the analog-to-digital conversion module AD in digital signal processor DSP is connected with current sensor；By analog digital conversion mould The analogue value that current sensor is exported by block AD is converted to digital quantity value；Pulse width in digital signal processor DSP Modulation module PWM is connected, by Pulse width modulation module with the driving module of spliced servomotor through photo-coupler OC The driving module of spliced servomotor is controlled by PWM；Quadrature coding pulse module in digital signal processor DSP QEP is connected with position sensor, and the signal sent by position sensor by quadrature coding pulse module QEP is converted into spelling Meet the mechanical angle φ that formula servomotor is current；And according to the following steps spliced servomotor be monitored and control:

Step 1: rotate with a spliced servomotor of standard driven by motor, measure spliced servomotor in the process rotated a circle In often rotate magnetic resistance moment T suffered when 1 degree_c, obtain altogether 360 discrete magnetic resistance moment T_cValue；

Step 2: 360 the discrete magnetic resistance moment T by Fourier space, step 1 obtained by digital signal processor DSP_c Value matching and be built into the magnetic resistance moment of spliced servomotor and the linear function expression of position of rotation

Wherein T_cIt is the magnetic resistance moment size of motor, T_cnIt is reluctance force harmonic wave cosine term coefficient, T_snIt is reluctance force harmonic sine term coefficient, φ is the mechanical angle of spliced servomotor, and τ is the pole span of spliced servomotor；

Step 3: disconnect the connection of standard electromotor and spliced servomotor；The assembling of spliced servomotor is put to needing use to set In Bei, power to spliced servomotor and make its autorotation work；With current sensor gather in rotary work spliced The three-phase electricity flow valuve of servomotor: A phase current values i_a, B phase current values i_bWith C phase current values i_c, and it is transferred to digital signal Processor DSP；CLARKE conversion three-phase electricity flow valuve carried out successively by digital signal processor DSP and PARK vector Conversion, by A phase current values i of Real-time Collection_a, B phase current values i_bWith C phase current values i_cIt is changed into direct-axis current value I_dWith Quadrature axis current value I_q；

Step 4: by digital signal processor DSP by the line of the reluctance force of spliced servomotor that obtained by step 2 with position of rotation Property function expressionWith motor torque COEFFICIENT K_tIt is divided by, it is thus achieved that with the compensation electric current I of change in location_qr:

I_qr=T_c(φ)/K_t；

Step 5: by control system speed ring PID, digital signal processor DSP is to direct-axis current value I_dWith quadrature axis current value I_qEnter Row operation obtains the theoretical reference electric current I of spliced servomotor^* _qv；By digital signal processor DSP by theoretical reference electric current I^* _qvWith the compensation electric current I with change in location obtained by step 4_qrSubtracting each other, obtained difference is referred to as actual quadrature axis reference current I^* _q, it is the electric current of the spliced servomotor of actual driving；Finally, the pulse width in digital signal processor DSP adjust Molding block PWM is by actual quadrature axis reference current I^* _qThe driving module of spliced servomotor it is transferred to through photo-coupler OC, Realize the real-time control to spliced servomotor.

The most according to claim 1 being compensated the method reducing spliced servomotor torque fluctuations by reluctance force, its feature exists In, spliced servomotor to be measured to a standard motor and is placed on monitor station jointly；On the rotor of standard electromotor Driving electric machine winding dish (1) is installed, the rotor of spliced servomotor to be measured is provided with servomotor wire spool (6), Edge and one end of the first connecting line (81) of driving electric machine winding dish (1) are connected, another of the first connecting line (81) End is connected with one end of ergometer (4), and the other end of ergometer (4) is connected with the edge of servomotor wire spool (6) Connect；One end of 3rd connecting line (83) is connected with the edge of servomotor wire spool (6), the 3rd connecting line (83) The other end connects pouring weight (9)；Being provided with an assembly pulley (10) at detection edge of table, the 3rd be connected with pouring weight (9) is even Wiring (83) naturally droops after walking around assembly pulley (10)；

Measure the magnetic resistance moment T of spliced servomotor_cStep as follows:

Step 1.1: in the case of tested model machine is cold, is driven spliced servomotor at the uniform velocity to rotate a circle by standard electromotor；By counting Word signal processor DSP the signal of position sensor is converted into spliced servomotor real-time rotate forward angle, pass through Ergometer (4) obtains loading moment value TL rotated forward when spliced servomotor often rotates 1 °₁, acquisition 360 altogether Individual loading moment value TL rotated forward₁；

Step 1.2: make standard electromotor drive spliced servomotor at the uniform velocity to reversely rotate one week, obtain spliced by ergometer (4) Loading moment value TL of reverse rotation when servomotor often reversely rotates 1 °₂, obtain altogether 360 loads reversely rotated Moment values TL₂；

Step 1.3: loading moment value TL rotated forward of same angular angle value will be rotated₁With loading moment value TL reversely rotated₂Take With loading moment T after arithmetic mean of instantaneous value_gDo difference, obtain magnetic resistance moment T_c:

$T_c=\frac{1}{2}(T_{L1}+T_{L2})-T_g$

In formula, loading moment T_gFor the pouring weight (9) moment to servomotor wire spool (6)；Obtain altogether 360 magnetic resistance moments T_cValue.

The most according to claim 1 being compensated the method reducing spliced servomotor torque fluctuations by reluctance force, its feature exists In, digital signal processor DSP uses the Fourier space on more than 5 rank to magnetic resistance moment T_cValue carries out nonlinear regression calculating.

The most according to claim 1 being compensated the method reducing spliced servomotor torque fluctuations by reluctance force, its feature exists In, digital signal processor DSP is to A phase current values i_a, B phase current values i_bWith C phase current values i_cCarry out PARK vector Needing current electrical angle θ obtaining spliced servomotor to be obtained by functional expression θ=2P Φ during conversion, wherein, φ is The mechanical angle that spliced servomotor is current, the current mechanical angle φ of spliced servomotor is by coaxial with servomotor The position sensor installed collects, and P is the number of pole-pairs of spliced servomotor.

The most according to claim 1 being compensated the method reducing spliced servomotor torque fluctuations by reluctance force, its feature exists In, described theoretical reference electric current I^* _qvMotor speed closed loop PI computing is utilized to obtain by digital signal processor DSP.

The most according to claim 2 being compensated the method reducing spliced servomotor torque fluctuations by reluctance force, its feature exists In, standard electromotor is the motor of Low-torque fluctuation, and its torque fluctuations is within 5%.