PX4 自动驾驶用户指南 (v1.12)

# 预解锁，解锁，锁定配置

机体是有可移动的部件的，其中一些在通电后会有潜在的危险性（特别是电机和螺旋桨）！

为了减少发生事故的可能性， PX4 有明确的载具部件供电状态：

  • 锁定： 电机或执行器不供电。
  • 预解锁： 电机/螺旋桨被锁定，但是没有危险的电子设备被供电（例如副翼，襟翼等）。
  • 解锁： 载具全部供电。 电机/螺旋桨可能转动（危险！）

注解

对于预解锁的载具，地面站可能显示锁定状态。 虽然技术上不适合预解锁的载具，但它是“安全的”。

用户可以控制进度，即使这些状态在载具上使用 安全开关 (可选) 和 一个 解锁开关/按钮 解锁手法, 或 MAVLink 命令 在地面控制器：

  • 安全开关 是载具上的控制 ** 必须使用它才能解锁载具， 而且也可防止预解锁（视配置而定）。 通常，安全开关被集成到 GPS 单元中，但也可能是一个单独的物理组件。

注意

解锁后的载具有潜在危险。 安全开关是防止意外解锁发生的一个附加机制。

  • 解锁开关是在遥控器上的一个开关或按钮，可以用来解锁载具和启动电机（安全开关不能阻止解锁）。

  • 解锁手法是一个在遥控器上的摇杆运动，可以用来替代解锁开关。

  • 也可以通过地面站发送 MAVLink 命令来解锁/锁定载具。

如果在解锁后的一段时间内没有起飞，和如果着陆后没有手动锁定， PX4 会自动锁定载具。 这减少了解锁的载具在地面上的时间。

PX4 允许您通过参数配置预解锁，解锁和锁定的方式。（参数可以通过QGroundControl地面站上的参数编辑器编辑），详见下文各节。

提示

解锁/锁定参数可以在Parameter Reference > Commander中找到（搜索COM_ARM_* 和 COM_DISARM_*）。

# 解锁手法

默认情况下，载具可以通过移动遥控器的油门/偏航摇杆到特定的位置，并保持 1 秒来解锁和锁定。

  • 解锁： 油门最小，偏航最大
  • 锁定： 油门最小，偏航最小

遥控器基于不同的模式有不同的手法（因为控制器模式会影响用于油门和偏航的摇杆）：

  • 美国手：
    • *解锁：*左摇杆到右下角。
    • *锁定：*左摇杆到左下角。
  • 日本手：
    • *解锁：*左摇杆到右边，右摇杆到下方。
    • *锁定：*左摇杆到左边，右摇杆到下方。

可以使用COM_RC_ARM_HYST参数来配置保持时间。

参数 描述
COM_RC_ARM_HYST 遥控器的摇杆在解锁/锁定发生之前必须保持在解锁/锁定的位置。（默认：1 秒）。

# 解锁按钮/开关

解锁按钮或者“瞬时开关”可以配置为触发解锁/锁定而不是基于手势解锁（设置解锁开关会禁止手势解锁）。 按钮应该保持按下（名义上）1 秒来解锁（当锁定时）或者锁定（当解锁时）。

一个两段开关也可以用来解锁或锁定，其相应的解锁或锁定命令通过开关上的转换发送的。

提示

两段解锁开关主要用于/推荐用于竞技无人机。

The switch or button is assigned (and enabled) using RC_MAP_ARM_SW, and the switch "type" is configured using COM_ARM_SWISBTN.

参数 描述
RC_MAP_ARM_SW RC arm switch channel (default: 0 - unassigned). If defined, the specified RC channel (button/switch) is used for arming instead of a stick gesture.

Note:

  • This setting disables the stick gesture!
  • This setting applies to RC controllers. It does not apply to Joystick controllers that are connected via QGroundControl. | | COM_ARM_SWISBTN | Arm switch is a momentary button.
  • 0: Arm switch is a 2-position switch where arm/disarm commands are sent on switch transitions.
    -1: Arm switch is a button or momentary button where the arm/disarm command ae sent after holding down button for set time (COM_RC_ARM_HYST). |

注解

The switch can also be set as part of QGroundControl Flight Mode configuration.

# 自动上锁

By default vehicles will automatically disarm on landing, or if you take too long to take off after arming. The feature is configured using the following timeouts.

参数 描述
COM_DISARM_LAND 降落后自动锁定超时时间. Default: 2s (-1 to disable).
COM_DISARM_PRFLT Time-out for auto disarm if too slow to takeoff. Default: 10s (<=0 to disable).

# 解锁顺序：预解锁模式 & 安全按钮

The arming sequence depends on whether or not there is a safety switch, and is controlled by the parameters COM_PREARM_MODE (Prearm mode) and CBRK_IO_SAFETY (I/O safety circuit breaker).

The COM_PREARM_MODE parameter defines when/if pre-arm mode is enabled ("safe"/non-throttling actuators are able to move):

  • Disabled: Pre-arm mode disabled (there is no stage where only "safe"/non-throttling actuators are enabled).
  • Safety Switch (Default): The pre-arm mode is enabled by the safety switch. If there is no safety switch then pre-arm mode will not be enabled.
  • Always: Prearm mode is enabled from power up.

If there is a safety switch then this will be a precondition for arming. If there is no safety switch the I/O safety circuit breaker must be engaged (CBRK_IO_SAFETY), and arming will depend only on the arm command.

The sections below detail the startup sequences for the different configurations

# 默认：COM_PREARM_MODE=Safety and Safety Switch

The default configuration uses safety switch to prearm. From prearm you can then arm to engage all motors/actuators. It corresponds to: COM_PREARM_MODE=1 (safety switch) and CBRK_IO_SAFETY=0 (I/O safety circuit breaker disabled).

The default startup sequence is:

  1. Power-up.
    • All actuators locked into disarmed position
    • Not possible to arm.
  2. Safety switch is pressed.
    • System now prearmed: non-throttling actuators can move (e.g. ailerons).
    • System safety is off: Arming possible.
  3. Arm command is issued.
    • The system is armed.
    • All motors and actuators can move.

# COM_PREARM_MODE=Disabled and Safety Switch

When prearm mode is Disabled, engaging the safety switch does not unlock the "safe" actuators, though it does allow you to then arm the vehicle. This corresponds to COM_PREARM_MODE=0 (Disabled) and CBRK_IO_SAFETY=0 (I/O safety circuit breaker disabled).

The startup sequence is:

  1. Power-up.
    • All actuators locked into disarmed position
    • Not possible to arm.
  2. Safety switch is pressed.
    • All actuators stay locked into disarmed position (same as disarmed).
    • System safety is off: Arming possible.
  3. Arm command is issued.
    • The system is armed.
    • All motors and actuators can move.

# COM_PREARM_MODE=Always and Safety Switch

When prearm mode is Always, prearm mode is enabled from power up. To arm, you still need the safety switch. This corresponds to COM_PREARM_MODE=2 (Always) and CBRK_IO_SAFETY=0 (I/O safety circuit breaker disabled).

The startup sequence is:

  1. Power-up.
    • System now prearmed: non-throttling actuators can move (e.g. ailerons).
    • Not possible to arm.
  2. Safety switch is pressed.
    • System safety is off: Arming possible.
  3. Arm command is issued.
    • The system is armed.
    • All motors and actuators can move.

# COM_PREARM_MODE=Safety or Disabled and No Safety Switch

With no safety switch, when COM_PREARM_MODE is set to Safety or Disabled prearm mode cannot be enabled (same as disarmed). This corresponds to COM_PREARM_MODE=0 or 1 (Disabled/Safety Switch) and CBRK_IO_SAFETY=22027 (I/O safety circuit breaker engaged).

The startup sequence is:

  1. Power-up.
    • All actuators locked into disarmed position
    • System safety is off: Arming possible.
  2. Arm command is issued.
    • The system is armed.
    • All motors and actuators can move.

# COM_PREARM_MODE=Always and No Safety Switch

When prearm mode is Always, prearm mode is enabled from power up. This corresponds to COM_PREARM_MODE=2 (Always) and CBRK_IO_SAFETY=22027 (I/O safety circuit breaker engaged).

The startup sequence is:

  1. Power-up.
    • System now prearmed: non-throttling actuators can move (e.g. ailerons).
    • System safety is off: Arming possible.
  2. Arm command is issued.
    • The system is armed.
    • All motors and actuators can move.

# 参数

参数 参数描述
COM_PREARM_MODE Condition to enter prearmed mode. 0: Disabled, 1: Safety switch (prearm mode enabled by safety switch; if no switch present cannot be enabled), 2: Always (prearm mode enabled from power up). Default: 1 (safety button).
CBRK_IO_SAFETY Circuit breaker for IO safety.

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