I'm having issues with the rectangle function. The error statement I'm getting for the code below is: ''Error using rectangle: Value must be numeric'' and I can't figure it out. I'm trying to get a simulated UAV to a goalpoint, but it keeps stopping

x=0;

filename='Zoe';

t=1000;

figure(1)
center=[0,0];
r=5;

ball_rad=0.4;

for count=1:1:10

      %Vint=50+5.*rand(1,1)
      loc_x=0;
      loc_y=0;
      loc_x=start_x;
      Vres=Vself
      clf;

      x_target=20+10*rand(1,1)
      y_target=20+10*rand(1,1)

      rectangle('Position',[x_target-ball_rad_2,y_target -ball_rad_2, ball_rad_2*2, ball_rad_2*2],...
          'Curvature',[1,1],...
          'Facecolor','b');
      for sdx=1:1:num_images
          ball_rad=0.4;

          rectangle('Position',[loc_x-ball_rad,loc_y-ball_rad,ball_rad*2,ball_rad*2],...
              'Curvature',[1,1],...
              'Facecolor','g');
          fisr=readfis('Get_to_Goal')

          distance_s=((loc_x-x_target)^2)+((loc_y-y_target)^2)
          distance=sqrt(distance_s)
          angle=atand(((y_target-loc_y))/(x_target-loc_x))

          AnimationOutput=evalfis([distance angle],fisr)
          r=distance*(sind(AnimationOutput(:,2)))
          r2=distance*(cosd(AnimationOutput(:,2)))

          if angle==0
              if loc_x_previous==x_target
                  loc_x=x_target
                  loc_y=loc_y+r2*(loc_y-y_target)/(abs(y_target-loc_y))
              elseif loc_y_previous==y_target
                  loc_y=y_target
                  loc_x=loc_x+r*(loc_x-x_target)/(abs(x_target-loc_x))
              end
          end        
          if loc_x>=x_target
              loc_x=x_target
          end
          if loc_y>=y_target
              loc_y=y_target
          end
          if y_target-loc_y<=0
              angle=0;
              if x_target-loc_x>0
              loc_x=loc_x-r*0.5*(loc_x-x_target)/(abs(x_target-loc_x));
              else
              loc_x=loc_x-r*0.5*(loc_x-x_target)/(abs(x_target-loc_x)); 
              end
          end

          axis([-22 42 -22 42]);
          title('MC Goal')
          drawnow;
        %%most of the rest of the code is a video writer

Answer 1

[Image Analyst]

Right before the for loop, put these lines of code with no semicolons. Tell us what you see in the command window:

whos x_target  ball_rad  y_target  ball_rad_2
x_target
y_target
ball_rad
ball_rad_2

[Zoe Lee]

I realized I had cleared out ball rad 2 from my initial inputs. When I put that in, then it gave me undefined x_target and y_target. When I defined those outside the for loop, I'm still getting this:

Error using rectangle: Value must be numeric. Is it a possible trigonometric error? I did account for that in my code, but perhaps I missed something.

[Image Analyst]

Can you answer my question? Please put those lines of code in and let me know what it says.

[Walter Roberson]

Are you using symbolic variables anywhere? What is showing up for

class([loc_x-ball_rad,loc_y-ball_rad,ball_rad*2,ball_rad*2])

[Zoe Lee]

Image Analyst, I thought I had. Sorry if I wasn't clear enough. When I put in those lines of code, it said that "ball_rad_2 was undefined".I fixed that problem. Then it said "x_target is undefined" and "y target is undefined", I fixed that, and it gave me "Error using rectangle: Value must be numeric" as I stated above.

Walter, I am not using symbolic variables, and when I use the code you gave me, it gives me 'double'.

Experimenting, I just found that viscircles doesn't give me the error that rectangle does, but I am still kind of curious on what the major difference is.

[Image Analyst]

No, those lines of code are supposed to come even before rectangle() is even executed. So what do they say?

[Zoe Lee]

That was before "rectangle" was executed. I'm not sure what else to tell you....

[Zoe Lee]

I appreciate your help though! If it's a bit too frustrating... I'll attempt to solve my issue with viscircles.

[Stephen23]

@Zoe Lee: Can you please upload the complete code by clicking the paperclip button.

[Zoe Lee]

There's the complete code. There are a lot of comments that only make sense to myself, but it's all there.

[Image Analyst]

I get this:

To use 'readfis', the following product must be licensed, installed, and enabled:
  Fuzzy Logic Toolbox
Error in test4 (line 64)
    fisr=readfis('Get_to_Goal')

So I've added the Fuzzy Toolbox to the product list in the upper right of this screen.

Also, you had the lines in there before rectangle() but you had a % in front of them all which means they were commented out. Not sure why you did that but when I uncommented them I get this:

      Name            Size            Bytes  Class     Attributes

      ball_rad        1x1                 8  double              
      ball_rad_2      1x1                 8  double              
      x_target        1x1                 8  double              
      y_target        1x1                 8  double              

    x_target =
              28.4071725598366
    y_target =
              22.5428217897153
    ball_rad =
                           0.4
    ball_rad_2 =
                           0.2

And it works for the first two calls to rectangle(). After that however, you call the fuzzy function and I can't continue. So you're just going to have to put these lines immediately before each call to rectangle:

clc;
whos x_target  ball_rad  y_target  ball_rad_2
x_target
y_target
ball_rad
ball_rad_2

and see what happens. Tell us what you see in the command window right before rectangle() throws the error.

[Walter Roberson]

I need your Get_to_Goal.fis to test.

[Zoe Lee]

Unfortunately, I would not be allowed to give that to you, as it is the core of my research, and uploading it here would jeopardize the integrity of my findings and future publications (i.e. if someone else comes here later, downloads, and uses it for their work).

Thank you all for your help! I've realized the viscircles command works better than the rectangle command for the scenario here, so I found a way around the initial problem. I should be ok without any more help.

Answer 2

[Zoe Lee]

When I do that, I get this output: Name Size Bytes Class Attributes

ball_rad        1x1                 8  double              
ball_rad_2      1x1                 8  double              
x_target        1x1                 8  double              
y_target        1x1                 8  double

x_target =

   22.7850

y_target =

   25.4688

ball_rad =

    0.4000

ball_rad_2 =

    0.2000

And then the error, of course...