Method 1: Characteristic curve a(n) in polynomial- or hyperbola form

In the range above the limit speed, the current acceleration is optionally specified by a third-order polynomial or by a hyperbola function. In the case of both characteristics, a constant acceleration akonst is used in the range below ngrenz. This corresponds to acceleration at nominal speed. The curves apply to both the speed build-up and slow-down phases.

Profile of acceleration based on a polynomial or hyperbole
Profile of acceleration based on a polynomial or hyperbole

Interpolation points on the drive curve a(n) are used to determine the coefficients of the curves. 4 or 3 interpolation points are required to determine them.

One interpolation point P1=(n1, (a(n1)) is already defined by the parameter for constant acceleration akonst and the limit speed ngrenz and the user can define the remaining 3 or 2 on the drive characteristic a(n). It is best for the abscissa values to be at a constant distance. The equations to determine the coefficients are listed below.

Acceleration profile based on polynomial or hyperbole with interpolation points
Acceleration profile based on polynomial or hyperbole with interpolation points

Polynomial

, relative speed

Example of curve determination

Interpolation point

Acceleration a [°/s2]

Speed n [°/s]

1

16000

12000

2

8000

24000

3

4000

36000

4

2000

48000

aconst = 16000 [°/s2] to nlimit = 12000 [°/s]

The following is obtained for the coefficients:

b3 = -1.92901234E-10 [s/°2]

b2 = 2.08333333E-5 [1/°]

b1 = -0.88888888 [1/s]

b0 = akonst = 16000 [°/s2]

As from nominal speed (nlimit) the characteristic profile is as follows::

Curve profile for nominal speed nlimit with polynomials
Curve profile for nominal speed nlimit with polynomials

Hyperbola

, normalised speed,



Example of curve determination

Interpolation point

Acceleration a [°/s2]

Speed n [°/s]

1

16000

12000

2

8000

24000

3

4000

36000

4

2000

48000

A_konstkonst = 16000[degrees/s2] to nlimit = 12000 [degrees/s]

The following is obtained for the coefficients:

b2 = 4.166666E-1[]

b3 = 2.857142E-2[]

b1 = 2.285714E4[°/s2]

As from nominal speed (nlimit) the characteristic profile is as follows::

Curve profile for nominal speed nlimit with hyperbola
Curve profile for nominal speed nlimit with hyperbola

Parameter

P-AXIS-00202

Type: 1 (hyperbola) or 2 (polynomial)

P-AXIS-00130

Limit speed nlimit

P-AXIS-00007

Constant acceleration aconst for n<nlimit

P-AXIS-00010

Minimum acceleration amin

P-AXIS-00026

Coefficient b1

P-AXIS-00027

Coefficient b2

P-AXIS-00028

Coefficient b3

Parameterisation examples

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beschl_kennlinie.typ         1                 Hyperbola shape

beschl_kennlinie.a_min       1400              [°/s*s]

beschl_kennlinie.n_grenz     12000000          [10-3 °/s]

beschl_kennlinie.a_konst     16000             [°/s*s]

beschl_kennlinie.b1          2.285714E4        [°/s*s]

beschl_kennlinie.b2          4.166666E-1       []

beschl_kennlinie.b3          -2.857142E-2      []

#

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beschl_kennlinie.typ         2                 Polynomial shape

beschl_kennlinie.a_min       2000              [°/s*s]

beschl_kennlinie.n_grenz     12000000          [10-3 °/s]

beschl_kennlinie.a_konst     16000             [°/s*s]

beschl_kennlinie.b1          -0.88888888       [1/s]

beschl_kennlinie.b2          2.08333333E-5     [1/°]

beschl_kennlinie.b3          -1.92901234E-10   [s/°²]

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