Question

O.K。，我很想弄清楚发生了什么。我在主循环中有一个case语句（状态6指的是下面示例输出中的情况）。有一段时间，事情很好，然后我开始得到乱七八糟的结果，其中一个简单的减法给出了错误的结果。这是代码片段：

  case turning:
Serial.print("state: ");
Serial.print(state);
Serial.print("Waypoint: ");
Serial.print(waypointIndex);
Serial.print(" Location: ");
Serial.print(location.x);
Serial.print("   ");
Serial.print(location.y);
Serial.print(" heading: ");
Serial.print(heading);
Serial.print("target heading: ");
Serial.print(targetHeading);
Serial.print(" heading delta: ");
headingDelta = fabs(heading-targetHeading);
Serial.print(headingDelta);
Serial.print("small? ");
Serial.print((headingDelta<0.25));
Serial.print("\n");

if (headingDelta < 0.25) {
  Stop();
  state = travel;
}
else {
  if (turn>=0) {
    Left(255,255);  // turn left
  }
  else {
    Right(255,255);  // turn right
  }
}
break;

这是输出的一部分：

state: 6Waypoint: 2 Location: 111.98   18.12 heading: 0.95target heading: 1.57 heading delta: 0.62small? 0

state: 6Waypoint: 2 Location: 111.98   18.12 heading: 0.95target heading: 1.57 heading delta: 0.62small? 0

state: 6Waypoint: 2 Location: 111.98   18.12 heading: 1.35target heading: 1.57 heading delta: 0.22small? 1

state: 6Waypoint: 3 Location: 142.73   47.69 heading: 0.55target heading: 0.00 heading delta: 0.00small? 0

state: 6Waypoint: 3 Location: 142.73   47.69 heading: 0.55target heading: 0.00 heading delta: 0.00small? 0

state: 6Waypoint: 3 Location: 142.73   47.69 heading: 0.55target heading: 0.00 heading delta: 0.00small? 0

随着第4个输出，突然我的标题Delta打印为零，当显然不是，但逻辑检查它是否小说它不小！

我把头发拉了出来。这是怎么回事？这是一个罗密欧，这是一个兼容Arduino的ATmega328主板。

Answer 1

看起来targetHeading已成为NaN或+/-Inf，而Serial.print(...)只在遇到其中一个值时输出0.0。在计算targetHeading时，也许你在某处除以0。

减法和晶圆厂工作，然后不作为程序运行

1 个答案: