CN109828534A - A kind of real time profile error compensating method of embedded cutting controller - Google Patents

Abstract

A kind of real time profile error compensating method of embedded cutting controller, includes the following steps: the deviation between the current location and desired locations by encoder feedback, obtains the direct position error E of X-axis and Y-axis_xAnd E_y, according to the deviation between present speed and desired speed, get indirect position error E in an interpolation cycle T inner product_x' and E_y'.According to profile errors model, direct profile errors ε is calculated₁=-C_xE_x+C_yE_y, and profile errors ε indirectly₂=-C_xE_x'+C_yE_y', take E '_c=max { ε₁,ε₂}.Based on the real time profile error estimator, using variant gain cross-coupling PID controller, to largest contours error E '_cReal-time compensation.Present invention can apply to the cutting of any nonlinear loci, calculate that maximum real time profile error speed is fast, high-efficient, it is good to the profile control adaptability of nonlinear loci, precision is high.

Description

A kind of real time profile error compensating method of embedded cutting controller

Technical field

The invention belongs to industrial numerical control device field of automation technology, it is related to a kind of applied to embedded cutting controller Real time profile error compensating method.

Background technique

With the acceleration of industrial automation process and the continuous development of computer technology, embedded microprocessor is more and more Ground is applied to modern industry field.For high-speed, high precision multiaxial motion system, it is embedded control integrated controller have at The advantages that this is low, compact-sized, small in size, laying-out is easy, electromagnetic interference is few.Domestic medium-sized and small enterprises move low and middle-end and control The demand of control equipment is increasing, and the related application of the Motion Control Platform is also increasingly mature, as cutting, template cutter, Ink jet printer etc..

It is cut in this type games in 3D printing, spray painting, cardboard, profile control is core technology therein, and profile errors are past Past is the prior performance indicator of comparison-tracking error.But in the actual production process, most of Motion Control Platform is mostly to select The method of speed planning, reasonable design locus interpolation period rarely have concern to profile control algolithm.Only a few applies profile The high-end Motion Control Platform of control technology also mainly uses traditional profile control strategy, is missed by reducing uniaxial tracking Difference reduces profile errors.However, a host of facts illustrate, the profile errors of uniaxial tracking error and system are not exclusively in positive The relationship of pass.Asynchronous between kinematic axis can cause profile errors to increase, on the other hand, even if synchronous in relative motion axis Under the premise of, for any deep camber nonlinear loci, it is possible to there is the phenomenon that tracking error reduces, profile errors increase.

Summary of the invention

In view of the above-mentioned problems, the present invention proposes a kind of real time profile error compensation side applied to embedded cutting controller Method, according to the origin cause of formation of profile errors, comprehensive displacement error and velocity error calculate time-varying coupling operator, real-time estimation largest contours Error model compensates the profile errors of any high speed deep camber nonlinear loci, to achieve the effect that high-accurate outline controls.

The technical solution adopted by the present invention to solve the technical problems is as follows:

A kind of real time profile error compensating method of embedded cutting controller, includes the following steps:

1) according to the deviation between the current location of encoder feedback and desired locations, the position of X-axis and Y-axis single shaft is obtained Error E_xAnd E_y, according to the deviation between the present speed and desired speed of encoder feedback, obtain the speed of X-axis and Y-axis single shaft Error V_xAnd V_y, velocity error is integrated in an interpolation cycle T, obtains the position due to caused by two axle speed errors Error E_x' and E_y'；

2) track profile error model is established, F (x, y)=0 is an arbitrary curve, P_aFor true location point, P_eFor expectation Location point, E_x、E_yIndicate the uniaxiality tracking error of X-axis and Y-axis, θ is the tangent line and X of corresponding position point osculating circle on reference locus The angle of axis, R are close radius of circle, are derived, are obtained according to geometrical relationship:

P is indicated with the uniaxiality tracking error of X-axis and Y-axis_aWith O_bThe relationship of point, it may be assumed that

x_a-x_b=Rsin θ-E_x (2)

y_a-y_b=-Rcos θ-E_y (3)

It is obtained after formula (2) (3) are substituted into formula (1):

Formula (4) is unfolded using Maclaurin formula:

It enablesTrack profile error model indicates are as follows:

ε=- C_xE_x+C_yE_y (6)

3) the reason of comprehensive profile errors formation, in conjunction with the direct position error E of X-axis and Y-axis single shaft_xAnd E_yWith due to speed Spend indirect position error E caused by error_x' and E_y', it proposes the expression formula (7) (8) of real time profile error estimator, obtains maximum Profile errors E_c' mathematical model, by formula (9) indicate；

ε₁=-C_xE_x+C_yE_y (7)

ε₂=-C_xE_x'+C_yE_y' (8)

E_c'=max { ε₁,ε₂} (9)

4) the largest contours error model obtained based on real time profile error estimator proposes a kind of improved variable-gain Cross-coupling controller calculates optimal compensation amount by controller in real time, realizes under embedded platform to the quick of arbitrary trajectory Compensation, cross-coupling controller K_cUsing the form of PID control, indicate are as follows:

The controller gain: K_dc=0.013, K_pc=2.235, K_ic=5.261.

The desired locations are chosen according to the track inflection point that interpolation software is planned, direct position error is desired inflection point coordinate With the difference of current position coordinates, velocity error is the difference of desired inflection point speed and present speed, and speed is in interpolation cycle T At the uniform velocity, therefore the product that gained indirect position error is exactly velocity error and interpolation cycle T is integrated.

The current position coordinates and present speed are obtained by encoder feedback, and last before the expectation inflection point Encoder feedback value is read in one interpolation cycle T.

Technical concept of the invention are as follows: in the motion process of multi-spindle machining platform track, tracking error be Track command and Difference between actual path is the performance indicator for measuring motion stabilization.Profile errors are points on actual path to reference to rail The minimum distance of mark is to measure the most important performance indicator of multiaxial motion precision.When real system is built, position detection is filled The motion platform being mounted on each motor shaft is set, encoder count directly reflects the tracking error of each axis, can use uniaxiality tracking Geometrical relationship between error carrys out real-time estimation profile errors, then compensates.

Beneficial effects of the present invention are mainly manifested in: in embedded cutting control platform, using the real time profile error It is fast, high-efficient to calculate maximum real time profile error speed, while considering location error and velocity error for estimator, to any The profile control adaptability of nonlinear loci is good, precision is high.

Detailed description of the invention

Fig. 1 is track profile error model schematic diagram.

Fig. 2 is the embedded cutting controller architecture block diagram based on real time profile error estimator.

Fig. 3 is to cut some non-linear profile track actual effect figure.

Specific embodiment

With reference to the accompanying drawing and specific example the invention will be further described.

In conjunction with FIG. 1 to FIG. 3, a kind of real time profile error compensating method of embedded cutting controller, comprising the following steps:

1) any nonlinear loci is parsed using interpolation software, records the desired locations point P of each inflection point_e's Coordinate and planning speed, while to desired locations point P_eThe tangent line of corresponding close radius of circle R and the osculating circle and the folder of X-axis Angle θ saves sin θ and cos θ list；

2) X-axis and Y-axis are read in the last one interpolation cycle that will reach inflection point according to the parsing to arbitrary trajectory The current location of encoder and current speed value do subtraction with the desired location and goal pace of the inflection point, obtain X-axis and Y-axis Uniaxial location error E_xAnd E_y, individual axis velocity error V_xAnd V_y, by velocity error multiplied by the interpolation cycle time, obtain X-axis and Y The indirect position error E of axis_x' and E_y'；

3) direct profile errors ε is calculated according to profile errors model₁, indirect profile errors ε₂, compare the two size, take big Value be largest contours error E_c', formula is as follows:

ε₁=-C_xE_x+C_yE_y

ε₂=-C_xE_x′+C_yE_y′

E_c'=max { ε₁,ε₂}

4) a kind of improved Variant Gain Cross coupling Control device is used, to largest contours before reaching next inflection point Error E_c' made up, structural block diagram is as shown in Figure 2.The cross-coupling controller K_cUsing the form of PID control, controller Gain is as follows:

K_dc=0.013, K_pc=2.235, K_ic=5.261.

Using the cutting controller application in the cutting of nonlinear loci, actual effect is run on embedded platform as schemed Shown in 3.Terminal actual path and reference locus coincide substantially, when being mutated deep camber wedge angle, although smoother deep camber Profile control precision in the case of circular arc is more inferior, remains in lesser error range, overall using effect is preferable.

Claims (4)

1. a kind of real time profile error compensating method of embedded cutting controller, which is characterized in that the method includes as follows Step:

1) by the deviation between encoder feedback current location and desired locations, the direct position error E of X-axis and Y-axis is obtained_x And E_y, according to the deviation between present speed and desired speed, obtain the velocity error V of X-axis and Y-axis_xAnd V_y, in an interpolation Velocity error is integrated in cycle T, obtains the indirect position error E due to caused by two axle speed errors_x' and E_y′；

2) it enablesEstablish track profile error model are as follows: ε=- C_xE_x+ C_yE_y；

3) the reason of comprehensive profile errors formation, according to direct position error E_xAnd E_yCalculate direct profile errors ε₁=-C_xE_x+ C_yE_y, according to indirect position error E_x' and E_y' calculate indirect profile errors ε₂=-C_xE_x'+C_yE_y', take maximum real time profile error E′_c=max { ε₁,ε₂}；

4) optimal compensation is calculated using variant gain cross-coupling PID controller based on the real time profile error estimator in real time Amount, to largest contours error E '_cIt compensates, the Variant Gain Cross coupling Control device gain: K_dc=0.013, K_pc= 2.235 K_ic=5.261.

2. the real time profile error compensating method of embedded cutting controller as described in claim 1, it is characterised in that: described Desired locations are chosen according to the track inflection point that interpolation software is planned, direct position error is that desired inflection point coordinate and current location are sat It is expected target difference, velocity error are the difference of inflection point speed and present speed, and speed is at the uniform velocity, therefore to accumulate in interpolation cycle T Indirect position error obtained by point is exactly the product of velocity error and interpolation cycle T.

3. the real time profile error compensating method of embedded cutting controller as claimed in claim 1 or 2, it is characterised in that: The current position coordinates and present speed are obtained by encoder feedback, and the last one interpolation before the expectation inflection point Encoder feedback value is read in cycle T.

4. the real time profile error compensating method of embedded cutting controller as claimed in claim 1 or 2, it is characterised in that: In the step 2), track profile error model is established, F (x, y)=0 is an arbitrary curve, P_aFor true location point, P_eFor Desired locations point, E_x、E_yIndicate the uniaxiality tracking error of X-axis and Y-axis, θ is the tangent line of corresponding position point osculating circle on reference locus With the angle of X-axis, R is close radius of circle, is derived, is obtained according to geometrical relationship:

P is indicated with the uniaxiality tracking error of X-axis and Y-axis_aWith O_bThe relationship of point, it may be assumed that

x_a-x_b=Rsin θ-E_x (2)

y_a-y_b=-Rcos θ-E_y (3)

It is obtained after formula (2) (3) are substituted into formula (1):

Formula (4) is unfolded using Maclaurin formula: