How to reduce angle values in a range between 0 and 360 deg?

56 次查看（过去 30 天）
Loren99
Loren99 2021-10-29
评论： Star Strider 2021-10-30
Hi everyone! I have obtained the angles alpha, beta and gamma in deg. However I would like to make a plot with values of gamma in a range between 0 and 360 deg (a sort of step-plot). Can anyone help me?
%B = load('PosRel.txt');
B = readmatrix('PosRelORF.csv');
time = B(:,1);
num_times = size(time,1);
%assegno valori iniziali degli angoli di Eulero
alpha0 = convang(5,'deg','rad');
beta0 = convang(5,'deg','rad');
gamma0 = convang(5,'deg','rad');
vAlphaBetaGamma0 = [alpha0, beta0, gamma0];
[vTime, vAlphaBetaGamma] = ode45(@funzione,time,vAlphaBetaGamma0);
alpha = vAlphaBetaGamma(:,1);
beta = vAlphaBetaGamma(:,2);
gamma = vAlphaBetaGamma(:,3);
alpha = convang(alpha,'rad','deg');
beta = convang(beta,'rad','deg');
gamma = convang (gamma,'rad','deg');
figure
plot(vTime,alpha,'k',vTime,beta,'r', vTime,gamma,'b');
legend('alpha','beta','gamma');
xlabel('Time (seconds');
ylabel('Angles (deg)');
function angularvelocities=funzione(t,attitudeangles)
angularvelocities = [0;0;0.4]; %rad/sec
end

请先登录，再回答此问题。

采纳的回答

Star Strider
Star Strider 2021-10-30
Ran in:
I am not certain what the desired result is.
Something like this came up once before, and since wrap2pi and wrap2360 are available here (I do not have the Mapping Toolbox), I wrote a function to emulate both, comparing it to those functions while experimenting with the results here. (Replace ‘360’ with ‘2*pi’ and ‘180’ wiith ‘pi’ to get the wrap2pi equivalent, or other values to get different behaviour.)
See if this produces the desired result —
a = linspace(-720, 720);
figure
plot(a, wrap_180(a))
grid
figure
plot(a, wrap_360(a))
grid
function wP1 = wrap_180(P1) % EMulates 'wrap2180'
mf = mod(P1,360);
wP1 = mf.*(mf<=180) + (mf-360).*(mf>180);
end
function wP1 = wrap_360(P1) % EMulates 'wrap2360'
mf = mod(P1,720);
wP1 = mf.*(mf<=360) + (mf-720).*(mf>360);
end
.
  2 个评论
Loren99
Loren99 2021-10-30
@Star Striderthe problem is that I have an angular velocity of 0.4 rad/s, it means 0.0637 revolutions per seconds. Multiplying 0.0637 for my interval of times (600 seconds) it means that in total I should have 38 full revolutions (from 0 to 360 degrees). Using wrap_360 and watching your plot, it seems that I have only two full revolutions(from 0 to 360 degrees)
Star Strider
Star Strider 2021-10-30
Ran in:
My calculations do not agree with yours.
I get 19 revolutions, not 38 —
av = 0.4; % Angular Velocity (rad/s)
tvl = 600; % Record Length (s)
rrevs = av*tvl % Revolutions (rad)
rrevs = 240
drevs = string(rad2deg(rrevs)) % Revolutions (°) ('string' Call To Show PRecision)
drevs = "13750.9871"
tv = linspace(0, tvl, tvl); % Time Vector (s)
tot_revs = rad2deg(av) * tv; % Total Revolutions In 'tvl'
% endrevs = tot_revs(end)
Nr_revs = nnz(islocalmax(wrap_360(tot_revs))) % Total Number Of Revolutions (Counts Peaks)
Nr_revs = 19
figure
subplot(2,1,1)
plot(tv, tot_revs)
grid
xlabel('Time (s)')
ylabel('Degrees')
subplot(2,1,2)
plot(tv, wrap_360(tot_revs))
grid
xlabel('Time (s)')
ylabel('Degrees')
function wP1 = wrap_360(P1) % Emulates 'wrapTo360'
mf = mod(P1,720);
wP1 = mf.*(mf<=360) + (mf-720).*(mf>360);
end
I cannot test my code with the actual data without the actual data.
.

请先登录，再进行评论。

更多回答（1 个）

Walter Roberson
Walter Roberson 2021-10-29
mask = 0 <= gamma & gamma <= 360;
plot(vTime(mask), alpha(mask), 'k', vTime(mask), beta, 'r', vTime(mask), gamma(mask), 'b');
  1 个评论
Loren99
Loren99 2021-10-30
@Walter Roberson I applied your suggestion, but that's not what I want to achieve. I would like to get a "zig zag plot", that is, when I get an angle value of 360 degrees (after one revolution), the plot goes back to zero and then starts growing again. 14000 degrees in the plot equals 23 revolutions per second.

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Resizing and Reshaping Matrices 的更多信息

标签

产品


版本

R2021b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by