function fncSr = fncSpeedRef(param,r,v,robStateLen)
  sp = [1, 2]; % 1 = x; 2 = y
  if (length(param) == 4)
                                % 'xsin' / 'xcos'
    strSinOcos = strcat(sprintf("%s", param(2:length(param))));

    if (param(1) == 'x')
      strSfx = strcat(sprintf("%i*%s(%i*t)",r,strSinOcos,v));
      strSfy = strcat(sprintf("%i",r));
                                % 'ysin' / 'ycos'
    elseif (param(1) == 'y')
      strSfx = strcat(sprintf("%i",r));
      strSfy = strcat(sprintf("%i*%s(%i*t)",r,strSinOcos,v));
    endif

  elseif (param(1) == 'c')
    if(param(2) == 'c')
                                %'circle'
      strSfx = strcat(sprintf("%i*cos(%i*t)",r,v));
      strSfy = strcat(sprintf("%i*sin(%i*t)",r,v));

    else
      strSfx = strcat(sprintf("%i*sin(%i*t)",r,v));
      strSfy = strcat(sprintf("%i*cos(%i*t)",r,v));
    endif

  elseif (param(1) == 's')
    strSinOcos = strcat(sprintf("%s", param(3:end)));
    if (length(param) > 1)
	    if (param(2) == 'y')
	      strSfx = strcat(sprintf("%i*%s(%i*t)",r,strSinOcos,v));
	      strSfy = strcat(sprintf("%i",0));
	                                % 'ysin' / 'ycos'
	    else  %if (param(2) == 'x')
	      strSfx = strcat(sprintf("%i",0));
	      strSfy = strcat(sprintf("%i*%s(%i*t)",r,strSinOcos,v));
	    endif
    else
      strSfx = strcat(sprintf("%i",r));
      strSfy = strcat(sprintf("%i",v));
    endif
  else
    printf("Karepmu opo ? \n\n bukak fungsi speedRef sek diwoco komen e \n\n");
  endif
  if (robStateLen==2)
    strAll = strcat("fncSr = @(t) [",strSfx, ";\ ", strSfy, "];");
  elseif(robStateLen==3)
    strAll = strcat("fncSr = @(t) [",strSfx, ";\ ", strSfy, ";\ 0];");
  else
  	printf("ERROR REFSPEED NOT SUPPORT!!");
  endif
  %% printf(strAll)
  eval(strAll);

  %% spx = sfx(t);
  %% spy = sfy(t);
endfunction