mirror of
https://gitee.com/mirrors_PX4/PX4-Autopilot.git
synced 2026-04-14 10:07:39 +08:00
186 lines
12 KiB
Markdown
186 lines
12 KiB
Markdown
# Basic Setup
|
|
|
|
## Configure the rover frame and outputs
|
|
|
|
1. Enable Rover support by flashing the [PX4 rover build](../config_rover/index.md#flashing-the-rover-build) onto your flight controller.
|
|
Note that this is a special build that contains rover-specific modules.
|
|
|
|
2. In the [Airframe](../config/airframe.md) configuration select the your rover type: _Generic Rover Ackermann_/_Generic Rover Differential_/_Generic Rover Mecanum_:
|
|
|
|
|
|
|
|
Select the **Apply and Restart** button.
|
|
|
|
::: info
|
|
If this airframe is not displayed and you have checked that you are using rover firmware (not the default), you can alternatively enable this frame by setting the [SYS_AUTOSTART](../advanced_config/parameter_reference.md#SYS_AUTOSTART) parameter directly to the following value:
|
|
|
|
| Rover Type | Значення |
|
|
| ------------ | -------- |
|
|
| Ackermann | `51000` |
|
|
| Differential | `50000` |
|
|
| Mecanum | `52000` |
|
|
|
|
|
|
:::
|
|
|
|
3. Open the [Actuators Configuration & Testing](../config/actuators.md) to map the motor/servo functions to flight controller outputs.
|
|
|
|
That is the minimum setup to use the rover in [Manual mode](../flight_modes_rover/manual.md#manual-mode).
|
|
|
|
:::info
|
|
The rest of the tuning on this page is not mandatory for [Manual mode](../flight_modes_rover/manual.md#manual-mode), but it will have an effect on the behaviour of the rover.
|
|
:::
|
|
|
|
:::warning
|
|
Do not skip the rest of this setup if you intend to use more sophisticated modes!
|
|
All parameters will be mandatory for all subsequent modes, except those tagged as `(Optional)`.
|
|
:::
|
|
|
|
## Geometric Parameters
|
|
|
|
First, we set up the geometric parameters of the rover:
|
|
|
|
|
|
|
|
Navigate to [Parameters](../advanced_config/parameters.md) in QGroundControl and set the parameters in the group for your frame type.
|
|
|
|
### Ackermann
|
|
|
|
1. [RA_WHEEL_BASE](#RA_WHEEL_BASE) [m]: Measure the distance from the back to the front wheels.
|
|
2. [RA_MAX_STR_ANG](#RA_MAX_STR_ANG) [deg]: Measure the maximum steering angle.
|
|
3. (Optional) [RA_STR_RATE_LIM](#RA_STR_RATE_LIM) [deg/s]: Maximum steering rate you want to allow for your rover.
|
|
|
|
::: tip
|
|
This value depends on your rover and use case.
|
|
For bigger rovers there might be a mechanical limit that is easy to identify by steering the rover at a standstill and increasing
|
|
[RA_STR_RATE_LIM](#RA_STR_RATE_LIM) until you observe the steering rate to no longer be limited by the parameter.
|
|
For smaller rovers you might observe the steering to be too aggressive. Set [RA_STR_RATE_LIM](#RA_STR_RATE_LIM) to a low value and steer the rover at a standstill.
|
|
Increase the parameter until you reach the maximum steering rate you are comfortable with.
|
|
|
|
:::
|
|
|
|
::: warning
|
|
A low maximum steering rate makes the rover worse at tracking steering setpoints, which can lead to a poor performance in the subsequent modes.
|
|
|
|
:::
|
|
|
|
### Differential
|
|
|
|
1. [RD_WHEEL_TRACK](#RD_WHEEL_TRACK) [m]: Measure the distance from the centre of the right wheel to the centre of the left wheel.
|
|
|
|
### Mecanum
|
|
|
|
1. [RM_WHEEL_TRACK](#RM_WHEEL_TRACK) [m]: Measure the distance from the centre of the right wheel to the centre of the left wheel.
|
|
|
|
## Speed Parameters
|
|
|
|
1. [RO_MAX_THR_SPEED](#RO_MAX_THR_SPEED) [m/s]: Drive the rover at full throttle and set this parameter to the observed value of the ground speed.
|
|
|
|
:::info
|
|
This parameter is also used for the feed-forward term of the closed loop speed control.
|
|
It will be further adjusted in the [velocity tuning](velocity_tuning.md) step.
|
|
|
|
:::
|
|
|
|
2. (Optional) [RO_ACCEL_LIM](#RO_ACCEL_LIM) [m/s^2]: Maximum acceleration you want to allow for your rover.
|
|
|
|
<a id="RO_ACCEL_LIM_CONSIDERATIONS"></a>
|
|
|
|
:::tip
|
|
Your rover has a maximum possible acceleration which is determined by the maximum torque the motor can supply.
|
|
This may or may not be appropriate for your vehicle and use case.
|
|
|
|
One approach to determine an appropriate value is:
|
|
|
|
1. From a standstill, give the rover full throttle until it reaches the maximum speed.
|
|
2. Disarm the rover and plot the `measured_speed_body_x` from [RoverSpeedStatus](../msg_docs/RoverSpeedStatus.md).
|
|
3. Divide the maximum speed by the time it took to reach it and set this as the value for [RO_ACCEL_LIM](#RO_ACCEL_LIM).
|
|
|
|
Some RC rovers have enough torque to lift up if the maximum acceleration is not limited.
|
|
If that is the case:
|
|
|
|
1. Set [RO_ACCEL_LIM](#RO_ACCEL_LIM) to a low value, give the rover full throttle from a standstill and observe its behaviour.
|
|
2. Increase [RO_ACCEL_LIM](#RO_ACCEL_LIM) until the rover starts to lift up during the acceleration.
|
|
3. Set [RO_ACCEL_LIM](#RO_ACCEL_LIM) to the highest value that does not cause the rover to lift up.
|
|
|
|
:::
|
|
|
|
3. (Optional) [RO_DECEL_LIM](#RO_DECEL_LIM) [m/s^2]: Maximum deceleration you want to allow for your rover.
|
|
|
|
:::tip
|
|
The same [considerations](#RO_ACCEL_LIM_CONSIDERATIONS) as in the configuration of [RO_ACCEL_LIM](#RO_ACCEL_LIM) apply.
|
|
|
|
:::
|
|
|
|
:::info
|
|
This parameter is also used for the calculation of the speed setpoint in modes that are [position controlled](position_tuning.md).
|
|
|
|
:::
|
|
|
|
## (Optional) Stick Input Mapping
|
|
|
|
Input shaping can be used to adjust the default linear mapping from stick inputs $\in [-1, 1]$ to normalized setpoints $\in [-1, 1]$. Applying this specifically to the steering input, can provide a smoother driving experience, by enabling the user to make small adjustments when the stick is close to the center, but still send large inputs when moving them to the edges.
|
|
We provide this input shaping through the super exponential function:
|
|
|
|
$$
|
|
\delta = \frac{(f \cdot x^3 + x(1-f)) \cdot (1-g)}{1-g \cdot |x|}
|
|
$$
|
|
|
|
with:
|
|
|
|
- $\delta \in [-1, 1]=$ Normalized steering setpoint.
|
|
- $x \in [-1, 1]=$ Normalized stick input.
|
|
- $f=$ [RO_YAW_EXPO](#RO_YAW_EXPO): `0` Purely linear input curve, `1` Purely cubic input curve.
|
|
- $g=$ [RO_YAW_SUPEXPO](#RO_YAW_SUPEXPO): `0` Pure Expo function, `0.7` reasonable shape enhancement for intuitive stick feel, `0.95` very strong bent input curve only near maxima have effect.
|
|
|
|
In [Manual mode](../flight_modes_rover/manual.md#manual-mode) we can additionally scale $\delta$ with an additional parameter $r$:
|
|
|
|
- Differential Rover: $r=$ [RD_YAW_STK_GAIN](#RD_YAW_STK_GAIN), which enables adjusting the slope of the input mapping. This leads to a normalized steering input $\hat{\delta} = \delta \cdot r \in$ [-[RD_YAW_STK_GAIN](#RD_YAW_STK_GAIN), [RD_YAW_STK_GAIN](#RD_YAW_STK_GAIN)].
|
|
- Mecanum Rover: $r=$ [RM_YAW_STK_GAIN](#RM_YAW_STK_GAIN), which enables adjusting the slope of the input mapping. This leads to a normalized steering input $\hat{\delta} = \delta \cdot r \in$ [-[RM_YAW_STK_GAIN](#RM_YAW_STK_GAIN), [RM_YAW_STK_GAIN](#RM_YAW_STK_GAIN)].
|
|
|
|
This scaling is useful to limit the normalized steering setpoint, if it is too aggressive for your rover in manual mode.
|
|
|
|
You can experiment with the relationships graphically using the [PX4 SuperExpo Rover calculator](https://www.desmos.com/calculator/gwm8lrlanx).
|
|
|
|
:::info
|
|
In [Acro](../flight_modes_rover/manual.md#acro-mode), [Stabilized](../flight_modes_rover/manual.md#stabilized-mode) and [Position](../flight_modes_rover/manual.md#position-mode) Mode, $\delta$ is instead scaled by $r=$ [RO_YAW_RATE_LIM](../advanced_config/parameter_reference.md#RO_MAX_THR_SPEED) for all rovers. This leads to a yaw rate setpoint $\dot{\psi} = \delta \cdot r \in$ [-[RO_YAW_RATE_LIM](../advanced_config/parameter_reference.md#RO_MAX_THR_SPEED), [RO_YAW_RATE_LIM](../advanced_config/parameter_reference.md#RO_MAX_THR_SPEED)]. This parameter is setup during [rate tuning](rate_tuning.md).
|
|
:::
|
|
|
|
:::info
|
|
The input shaping through [RO_YAW_EXPO](#RO_YAW_EXPO) and [RO_YAW_SUPEXPO](#RO_YAW_SUPEXPO) applies for all manual modes, while [RD_YAW_STK_GAIN](#RD_YAW_STK_GAIN)/[RM_YAW_STK_GAIN](#RM_YAW_STK_GAIN) only affects full manual mode.
|
|
:::
|
|
|
|
You can now continue the configuration process with [rate tuning](rate_tuning.md).
|
|
|
|
## Огляд параметрів
|
|
|
|
| Параметр | Опис | Unit |
|
|
| -------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------- | ------- |
|
|
| <a id="RO_MAX_THR_SPEED"></a>[RO_MAX_THR_SPEED](../advanced_config/parameter_reference.md#RO_MAX_THR_SPEED) | Speed the rover drives at maximum throttle | $m/s$ |
|
|
| <a id="RO_ACCEL_LIM"></a>[RO_ACCEL_LIM](../advanced_config/parameter_reference.md#RO_ACCEL_LIM) | (Optional) Maximum allowed acceleration | $m/s^2$ |
|
|
| <a id="RO_DECEL_LIM"></a>[RO_DECEL_LIM](../advanced_config/parameter_reference.md#RO_DECEL_LIM) | (Optional) Maximum allowed deceleration | $m/s^2$ |
|
|
| <a id="RO_YAW_EXPO"></a>[RO_YAW_EXPO](../advanced_config/parameter_reference.md#RO_YAW_EXPO) | (Optional) Yaw rate expo factor | $-$ |
|
|
| <a id="RO_YAW_SUPEXPO"></a>[RO_YAW_SUPEXPO](../advanced_config/parameter_reference.md#RO_YAW_SUPEXPO) | (Optional) Yaw rate super expo factor | $-$ |
|
|
|
|
### Ackermann Specific
|
|
|
|
| Параметр | Опис | Unit |
|
|
| ----------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------- | ----- |
|
|
| <a id="RA_WHEEL_BASE"></a>[RA_WHEEL_BASE](../advanced_config/parameter_reference.md#RA_WHEEL_BASE) | Wheel base | $m$ |
|
|
| <a id="RA_MAX_STR_ANG"></a>[RA_MAX_STR_ANG](../advanced_config/parameter_reference.md#RA_MAX_STR_ANG) | Maximum steering angle | $deg$ |
|
|
| <a id="RA_STR_RATE_LIM"></a>[RA_STR_RATE_LIM](../advanced_config/parameter_reference.md#RA_STR_RATE_LIM) | (Optional) Maximum allowed steering rate | deg/s |
|
|
|
|
### Differential Specific
|
|
|
|
| Параметр | Опис | Unit |
|
|
| ----------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------ | ---- |
|
|
| <a id="RD_WHEEL_TRACK"></a>[RD_WHEEL_TRACK](../advanced_config/parameter_reference.md#RD_WHEEL_TRACK) | Wheel track | $m$ |
|
|
| <a id="RD_YAW_STK_GAIN"></a>[RD_YAW_STK_GAIN](../advanced_config/parameter_reference.md#RD_YAW_STK_GAIN) | (Optional) Yaw stick gain for Manual mode | $-$ |
|
|
|
|
### Mecanum Specific
|
|
|
|
| Параметр | Опис | Unit |
|
|
| ----------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------ | ---- |
|
|
| <a id="RM_WHEEL_TRACK"></a>[RM_WHEEL_TRACK](../advanced_config/parameter_reference.md#RM_WHEEL_TRACK) | Wheel track | $m$ |
|
|
| <a id="RM_YAW_STK_GAIN"></a>[RM_YAW_STK_GAIN](../advanced_config/parameter_reference.md#RM_YAW_STK_GAIN) | (Optional) Yaw stick gain for Manual mode | $-$ |
|