Lego 88004 舵机参数

日期：2015年2月22日
作者：R. G.
LegoCar

第一组

视频及数据来源：这里（需要翻墙）。以下是视频介绍中的一部分：

Power Functions Servo Motor turn through the 15 positions corresponding to the duty cycle of Arduino PWM signal:

Position -7 Duty Cycle: 100%, analogWrite(): 255, C1: +, C2: - (90 degrees counter-clockwise)
Position -6 Duty Cycle: 88.2%, analogWrite(): 225, C1: +, C2: -
Position -5 Duty Cycle: 76.0%, analogWrite(): 194, C1: +, C2: -
Position -4 Duty Cycle: 63.5%, analogWrite(): 162, C1: +, C2: -
Position -3 Duty Cycle: 50.1%, analogWrite(): 128, C1: +, C2: -
Position -2 Duty Cycle: 38.0%, analogWrite(): 97, C1: +, C2: -
Position -1 Duty Cycle: 25.8%, analogWrite(): 66, C1: +, C2: -
Position 0 Duty Cycle: 0%, analogWrite(): 0 (center)
Position 1 Duty Cycle: 25.8%, analogWrite(): 66, C1: -, C2: +
Position 2 Duty Cycle: 38.0%, analogWrite(): 97, C1: -, C2: +
Position 3 Duty Cycle: 50.1%, analogWrite(): 128, C1: -, C2: +
Position 4 Duty Cycle: 63.5%, analogWrite(): 162, C1: -, C2: +
Position 5 Duty Cycle: 76.0%, analogWrite(): 194, C1: -, C2: +
Position 6 Duty Cycle: 88.2%, analogWrite(): 225, C1: -, C2: +
Position 7 Duty Cycle: 100%, analogWrite(): 255, C1: -, C2: + (90 degrees clockwise)

数据整理如下：

至于作者是如何获得这些数据的，尚不明确。

第二组

视频及数据来源：这里（需要翻墙）。在视频介绍中有提到：

Motor is controlled by PWM signals, with a frequency of 1150Hz, and duty cycles of: 0%, 26.6%, 38.9%, 51.2%, 63.0%, 75.0%, 87.2% and 100%.

在视频中，作者展示了通过万用表及示波器测得的PWM波形占空比。其中，万用表测得的数据如下：

Level 1 - 26.2%
Level 2 - 38.7%
Level 3 - 51.2%
Level 4 - 63.7%
Level 5 - 76.2%
Level 6 - 88.7%
Level 7 - 100.0%

用示波器测得的数据如下：

Level 1 - 27%
Level 2 - 39%
Level 3 - 51%
Level 4 - 63%
Level 5 - 75%
Level 6 - 87%
Level 7 - 100%

更多相关内容，请查看：

• 国外玩家Philippe对Power Function系列的介绍以及对舵机的测试；
• 另外一个玩家对Lego官方红外遥控器的测试

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[1] 此函数为Arduino输出PWM信号的控制函数，取值[0,255]，对应零占空比及满占空比 ↩
[2] 表格中的C1和C2如下图所示：
↩
[3] 此处的ccw（及下方的cw）参考的是“面对舵机正面”的方位 ↩