CN103618482A - Method for generating pulses with symmetric trapezoid acceleration and deceleration - Google Patents

Abstract

The invention provides a method for generating pulses with symmetric trapezoid acceleration and deceleration. The method for generating the pulses with symmetric trapezoid acceleration and deceleration comprises the steps that firstly, data are initialized, wherein the initial velocity in the time zero of trapezoid acceleration, the initial velocity at the zero moment of trapezoid deceleration and the number of pulses in the acceleration process or the deceleration process are calculated; secondly, the frequency of pulses in the constant acceleration process and the frequency of pulses in the constant deceleration process are obtained, wherein a pulse frequency value calculated when the constant acceleration process stops serves as a pulse frequency value used when the constant deceleration process begins. Due to the fact that real-time control over each pulse in the operation process of a motor is carried out, the pulses with completely-symmetric acceleration and deceleration can be obtained.

Description

A kind of method that produces symmetrical trapezoidal acceleration and deceleration pulse

Technical field

The present invention relates to a kind of method that produces symmetrical trapezoidal acceleration and deceleration pulse.

Background technology

Along with the fast development of equipment manufacture, the performance of automation equipment is badly in need of improving, and motor is typical actuator in automation equipment, and the quality of control system runnability depends on whether the control of motor is reached to optimum state to a great extent.In research Electric Machine Control, find that the output pulse of most of controllers is asymmetric in acceleration and moderating process, will cause like this motor to stop the rotating speed that rotating speed constantly can not reach expectation, can have influence on motor and accurately control the performance of occasion.Traditional algorithm, the control curve of output can reach symmetrical effect in theory, in processor, realize and but have certain difference with theory, actual acceleration and deceleration stage output pulse frequency can stop in the pulse frequency higher than calculating in theory, and acceleration and deceleration stage umber of pulse is unpredictable, easily affects control precision.

Summary of the invention

The technical problem solving

The problem existing for solving prior art, the present invention proposes a kind of method that produces symmetrical trapezoidal acceleration and deceleration pulse.

Technical scheme

The present invention improves existing algorithm, and the calculated value that will speed up termination when slowing down is assigned to the value that reduction of speed starts, and can reach like this effect of acceleration and deceleration symmetry, is conducive to accurately control the run location of motor in motion control.

Technical scheme of the present invention is:

A kind of described method that produces symmetrical trapezoidal acceleration and deceleration pulse, is characterized in that: adopt following steps:

Step 1: initialization data:

Step 1.1: adopt formula g=f ₁-β/(2f ₁) obtain trapezoidal acceleration and deceleration zero initial velocity g constantly, wherein f ₁be the initial velocity value that motor is set, β is motor acceleration;

Step 1.2: utilize formula { [g+ (g+ β t _m)]/2}t _m=m-1 obtains the umber of pulse m of accelerator or moderating process, wherein t _mto accelerate or total time of moderating process;

Step 2: enter even accelerator, calculate the frequency of each pulse in even accelerator, and the accelerator umber of pulse obtaining according to step 1 determines that even accelerator finishes;

Step 3: after even accelerator finishes, with motor actuating speed constant-speed operation, then enter even moderating process;

Step 4: enter even moderating process, in even moderating process, the pulse frequency value that when the even accelerator of usining stops, the pulse frequency value of calculating starts as even moderating process; Calculate the frequency of each pulse in even moderating process, and the moderating process umber of pulse obtaining according to step 1 determines that even moderating process finishes.

Beneficial effect

The present invention improves on the basis of existing motor control method, by the processing to initial velocity, acceleration, actuating speed, deceleration, these parameters of termination speed, can draw the umber of pulse needing in motor operation course, and the frequency of each pulse.Real-time control by each pulse in motor operation course, just can obtain the pulse of acceleration and deceleration full symmetric.

Accompanying drawing explanation

Fig. 1: flow chart of the present invention;

Fig. 2: the pulse train in trapezoidal acceleration and deceleration process constantly;

Fig. 3: the moment waveform of asymmetric acceleration and deceleration process;

Fig. 4: the moment waveform of symmetrical acceleration and deceleration process;

Fig. 5: the oscillogram of the actual output in embodiment.

Embodiment

Below in conjunction with specific embodiment, the present invention is described:

Given first principle of the present invention, for the pulse train in the trapezoidal acceleration and deceleration process shown in Fig. 2 constantly, when motor is with initial velocity f ₁start, with acceleration β, accelerate, with actuating speed f _sconstant-speed operation, the rate equation of motor can be expressed as: f=g+ β t, wherein g represents a value lower than toggle speed.

T in Fig. 2 ₁, t ₂, t ₃, t ₄, t ₅..., t _mrepresent the initial time that different frequency pulse sends, in each time interval, a step angle of motor rotation, so each little trapezoidal area is 1.The time interval Δ t of two adjacent pulses _m=t _m+1– t _m.This pulse frequency f=1/ Δ t constantly exporting _m, the pulse frequency of this pulse frequency during with this center time point is identical.

In Fig. 2, if t=Δ t ₁/ 2 o'clock, at Δ t ₁=1/f ₁time, f=g+ β t can become f ₁=g+ Δ t ₁/ 2=g+ β/(2f ₁), g=f ₁-β/(2f ₁).

T in Fig. 2 _mconstantly, there is m-1 pulse to produce, so to t _mtrapezoidal integration constantly can obtain { [g+ (g+ β t _m)]/2}t _m=m-1, obtains t _m={ [g ²+ 2 (m-1) β)] ^1/2-g}/β, the time interval that can obtain adjacent two pulses is: Δ t _m=t _m+1-t _m={ (g ²+ 2m β) ^1/2-[g ²+ 2 (m-1) β)] ^1/2}/β, frequency that can each pulse in acceleration and deceleration process is: f _m=1/ Δ t _m={ (g ²+ 2m β) ^1/2+ [g ²+ 2 (m-1) β)] ^1/2}/2.

According to above-mentioned principle, the method that produces symmetrical trapezoidal acceleration and deceleration pulse in the present embodiment adopts following steps:

Step 1: initialization data:

Step 1.1: adopt formula g=f ₁-β/(2f ₁) obtain trapezoidal acceleration and deceleration zero initial velocity g constantly, wherein f ₁be the initial velocity value that motor is set, β is motor acceleration;

Step 1.2: utilize formula { [g+ (g+ β t _m)]/2}t _m=m-1 obtains the umber of pulse m of accelerator or moderating process, wherein t _mto accelerate or total time of moderating process; So just can guarantee to control motor in the operational mode that automatically switches of different stages.

Step 2: enter even accelerator, calculate the frequency of each pulse in even accelerator, and the accelerator umber of pulse obtaining according to step 1 determines that even accelerator finishes;

Step 3: after even accelerator finishes, with motor actuating speed constant-speed operation, then enter even moderating process;

Step 4: enter even moderating process, in even moderating process, the pulse frequency value that when the even accelerator of usining stops, the pulse frequency value of calculating starts as even moderating process; Calculate the frequency of each pulse in even moderating process, and the moderating process umber of pulse obtaining according to step 1 determines that even moderating process finishes.

If the pulse frequency value that the pulse frequency value of calculating when not usining even accelerator termination here starts as even moderating process, can cause moderating process to take actuating speed value calculates as initial value, like this under certain deceleration pulse, pulse frequency when motor stops is larger, easy like this motor is caused to certain damage.

In the present embodiment, whole method realizes in FPGA, the pulse that can observe control output by the waveform of output is symmetrical (shown in Fig. 5), realized acceleration initially identical with deceleration termination pulse frequency constantly, the pulse frequency that realization should reach when arriving deceleration termination with given umber of pulse.The symmetrical acceleration and deceleration pulse that this method produces, is conducive to control the pulse frequency of slowing down while stopping, and can make like this motor improve a lot aspect vibration characteristics.

Claims (1)

1. a method that produces symmetrical trapezoidal acceleration and deceleration pulse, is characterized in that: adopt following steps:

Step 1: initialization data:

Step 1.1: adopt formula g=f ₁-β/(2f ₁) obtain trapezoidal acceleration and deceleration zero initial velocity g constantly, wherein f ₁be the initial velocity value that motor is set, β is motor acceleration;

Step 1.2: utilize formula { [g+ (g+ β t _m)]/2}t _m=m-1 obtains the umber of pulse m of accelerator or moderating process, wherein t _mto accelerate or total time of moderating process;

Step 2: enter even accelerator, calculate the frequency of each pulse in even accelerator, and the accelerator umber of pulse obtaining according to step 1 determines that even accelerator finishes;

Step 3: after even accelerator finishes, with motor actuating speed constant-speed operation, then enter even moderating process;

Step 4: enter even moderating process, in even moderating process, the pulse frequency value that when the even accelerator of usining stops, the pulse frequency value of calculating starts as even moderating process; Calculate the frequency of each pulse in even moderating process, and the moderating process umber of pulse obtaining according to step 1 determines that even moderating process finishes.

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