MATLAB: How to generate a number of pulses

cdprMATLABposition controlpulseSimscapesimulinkspecific number of pulsestep numberstepper motor

I am working on a cable robot project where I am using stepper motors to roll and unleash the winches to control the position. In order for the object to go to a certain position, the motors need to take a specific number of steps.

The pulse generator does not let me define the number of pulses. What can i use or what should i do in order the generate pulses with a certain amount?

(I can not use a time based solution such as; use the time it takes for 100 pulses to be generated and stop)

Best Answer

Use a "Counter Limited" block. Set the limit to be a large number and sample time to be 1. Compare (<=) it to a Constant block (the number of pulses you want). Use the output to enable an "enabled subsystem". Inside it is a Pulse Generator. Set the period to be 1 and 50% pulse width. Run simulation in discrete with 0.5 simulation step time. You will get the number of pulses you want.

Related Solutions

MATLAB: How to generate a pulse with variable frequency

In this model, the number of pulses and the frequency of the pulse are coupled. The simulation step, the sample time of the counter and the frequency of the pulse generator all need to work together to get the desired output. After you got 10 pulses, if you double or half the frequency of the pulse generator, you won't get the desired output.

Varying the frequency of the pulse is a tough task. Many blocks have frequency as a parameter, not a time-varying input.

I have a suggestion. Make f as an input, multiple it with 2*Pi and then use "Fcn" block to do the sin() operation then you will get sin(2*pi*f) which is a variable-frequency sine wave. Compare it with zero will give you the pulse athough the pulse width is also changing.

Then you will have some blocks to count the pulses. If the pulse signal has a rising edge, add one. Otherwise, do nothing. Compare the counter with your preset number of pulses. Use this comparison to control a Swith, passing either the pulse signal or zero.

Voila

MATLAB: How to generate a repetition of impulse response when I feed the system with repetition of pulses

We can use the Control System Toolbox to do this.

The following code generates the system from the transfer function using 'tf' function

close all, clear all, clc
t=[0:.2e-3:1];             % Time vector
C=1e-2; L=20e-4; R=80e-3;       % System parameters
a=1; b=[L*C R*C 1];             % Denominators and numerators
sys=tf([a],[b])                 % Transfer function
impulse(sys)                    % Just a single pulse

Then we can generate the repetition of pulses and invoke the system impulse response using 'lsim' function.

% Generate input pulses
dt = 0.0002;                      %Sample rate
tend = 2.5;                       %Simulation period
t = 0:dt:tend;
period = 0.5;                     %Period of the input pulses
u = zeros(length(t),1);
for i=1:length(t)
    if rem(t(i),0.5)==0
        u(i)=1;
    end
end
% Invoke the system response
% sysd = c2d(sys,dt);             % Continuous to discrete system conversion.
[y yt] = lsim(sys,u,t);
y = y/dt;                         % Normalize with sample time.
% Plot the input and the output.
subplot(2,1,1);
plot(t,u);
title('Input');
subplot(2,1,2);
plot(yt,y);
title('Impulse Responce');

Best Answer

Related Solutions

MATLAB: How to generate a pulse with variable frequency

MATLAB: How to generate a repetition of impulse response when I feed the system with repetition of pulses

Related Question