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0524a374d9
* fix(drivers/uavcannode): make CANNODE_NODE_ID the sole node ID policy The startup bootloader_app_shared_write() never reached the bootloader: it only accepts App-signed data and invalidates the shared region on every boot. The only consumer was uavcannode itself on a restart without a reset (nsh stop/start), where the persisted bus_speed=0 made the CAN driver init fail and left the node off the bus. The bootloader learns our node ID exclusively through the firmware update handoff in cb_beginfirmware_update, which already carries the static ID. CANNODE_NODE_ID now overrides the bootloader handoff only when nonzero, so the default (0) reuses the ID the bootloader already allocated instead of running allocation a second time. The handoff is ignored unless it carries a valid bitrate, healing regions poisoned by firmware that wrote bus_speed=0. Max is 125 because 126/127 are reserved for debug tools by DroneCAN convention, matching UAVCAN_NODE_ID. Signed-off-by: Jacob Dahl <dahl.jakejacob@gmail.com> * fix(drivers/uavcannode): harden bootloader handoff validation Invalidate the shared region whenever it was read valid, not only when the handoff is accepted, so stale data cannot linger on boards whose bootloader never invalidates it. Require a plausible bitrate (the CANNODE_BITRATE minimum) rather than nonzero: the canbootloader alt-app update path can hand off bus_speed = CAN_UNDEFINED (999). Reword the invalid-param error, which claimed dynamic allocation while keeping the bootloader handoff. Signed-off-by: Jacob Dahl <dahl.jakejacob@gmail.com> --------- Signed-off-by: Jacob Dahl <dahl.jakejacob@gmail.com>
140 lines
7.4 KiB
Markdown
140 lines
7.4 KiB
Markdown
# ARK Flow
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ARK Flow is an open source [DroneCAN](index.md) [optical flow](../sensor/optical_flow.md), [distance sensor](../sensor/rangefinders.md), and IMU module.
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## Where to Buy
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Order this module from:
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- [ARK Electronics](https://arkelectron.com/product/ark-flow/) (US)
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## Hardware Specifications
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- [Open Source Schematic and BOM](https://github.com/ARK-Electronics/ARK_Flow)
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- Sensors
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- PixArt PAW3902 Optical Flow Sensor
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- Tracks under super low light condition of >9 lux
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- Wide working range from 80mm up to 30m
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- Up to 7.4 rad/s
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- 40mW IR LED built onto board for improved low light operation
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- Broadcom AFBR-S50LV85D Time-of-Flight Distance Sensor
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- Integrated 850 nm laser light source
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- Field-of-View (FoV) of 12.4° x 6.2° with 32 pixels
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- Typical distance range up to 30m
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- Operation of up to 200k Lux ambient light
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- Works well on all surface conditions
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- Transmitter beam of 2° x 2° to illuminate between 1 and 3 pixels
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- Bosch BMI088 6-Axis IMU or Invensense ICM-42688-P 6-Axis IMU
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- STM32F412CEU6 MCU
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- Two Pixhawk Standard CAN Connectors (4 Pin JST GH)
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- Pixhawk Standard Debug Connector (6 Pin JST SH)
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- Software-toggleable built in CAN termination resistor
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- Small Form Factor
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- 3cm x 3cm x 1.4cm
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- LED Indicators
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- USA Built
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## Hardware Setup
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### Wiring
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The ARK Flow is connected to the CAN bus using a Pixhawk standard 4 pin JST GH cable.
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For more information, refer to the [CAN Wiring](../can/index.md#wiring) instructions.
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### Mounting
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The recommended mounting orientation is with the connectors on the board pointing towards **back of vehicle**, as shown in the following picture.
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This corresponds to the default value (`0`) of the parameter [SENS_FLOW_ROT](../advanced_config/parameter_reference.md#SENS_FLOW_ROT).
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Change the parameter appropriately if using a different orientation.
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The sensor can be mounted anywhere on the frame, but you will need to specify the focal point position, relative to vehicle centre of gravity, during [PX4 configuration](#px4-configuration).
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## Firmware Setup
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ARK Flow runs the [PX4 DroneCAN Firmware](px4_cannode_fw.md).
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As such, it supports firmware update over the CAN bus and [dynamic node allocation](index.md#node-id-allocation).
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ARK Flow boards ship with recent firmware pre-installed, but if you want to build and flash the latest firmware yourself see [PX4 DroneCAN Firmware > Building the Firmware](px4_cannode_fw.md#building-the-firmware).
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- Firmware target: `ark_can-flow_default`
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- Bootloader target: `ark_can-flow_canbootloader`
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## Flight Controller Setup
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::: info
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The Ark Flow will not boot if there is no SD card in the flight controller when powered on.
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:::
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### Enable DroneCAN
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The steps are:
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- In _QGroundControl_ set the parameter [UAVCAN_ENABLE](../advanced_config/parameter_reference.md#UAVCAN_ENABLE) to `2` for dynamic node allocation (or `3` if using [DroneCAN ESCs](../dronecan/escs.md)) and reboot (see [Finding/Updating Parameters](../advanced_config/parameters.md)).
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- Connect ARK Flow CAN to the Pixhawk CAN.
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Once enabled, the module will be detected on boot.
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Flow data should arrive at 100Hz.
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Distance sensor data should arrive at 40Hz
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DroneCAN configuration in PX4 is explained in more detail in [DroneCAN > Enabling DroneCAN](../dronecan/index.md#enabling-dronecan).
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### PX4 Configuration
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First set the parameters to [Enable DroneCAN](#enable-dronecan) (as shown above).
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Then set the EKF optical flow parameters to enable fusing optical flow measurements for velocity calculation, and define offsets if the sensor is not centred within the vehicle.
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Set the following parameters in _QGroundControl_:
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- Enable optical flow fusion by setting [EKF2_OF_CTRL](../advanced_config/parameter_reference.md#EKF2_OF_CTRL).
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- To optionally disable GPS aiding, set [EKF2_GPS_CTRL](../advanced_config/parameter_reference.md#EKF2_GPS_CTRL) to `0`.
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- Enable [UAVCAN_SUB_FLOW](../advanced_config/parameter_reference.md#UAVCAN_SUB_FLOW).
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- Enable [UAVCAN_SUB_RNG](../advanced_config/parameter_reference.md#UAVCAN_SUB_RNG).
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- Set [EKF2_RNG_CTRL](../advanced_config/parameter_reference.md#EKF2_RNG_CTRL) to `1`.
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- Set [EKF2_RNG_A_HMAX](../advanced_config/parameter_reference.md#EKF2_RNG_A_HMAX) to `10`.
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- Set [EKF2_RNG_QLTY_T](../advanced_config/parameter_reference.md#EKF2_RNG_QLTY_T) to `0.2`.
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- Set [UAVCAN_RNG_MIN](../advanced_config/parameter_reference.md#UAVCAN_RNG_MIN) to `0.08`.
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- Set [UAVCAN_RNG_MAX](../advanced_config/parameter_reference.md#UAVCAN_RNG_MAX) to `30`.
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- Set [SENS_FLOW_MINHGT](../advanced_config/parameter_reference.md#SENS_FLOW_MINHGT) to `0.08`.
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- Set [SENS_FLOW_MAXHGT](../advanced_config/parameter_reference.md#SENS_FLOW_MAXHGT) to `25`.
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- Set [SENS_FLOW_MAXR](../advanced_config/parameter_reference.md#SENS_FLOW_MAXR) to `7.4` to match the PAW3902 maximum angular flow rate.
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- The parameters [EKF2_OF_POS_X](../advanced_config/parameter_reference.md#EKF2_OF_POS_X), [EKF2_OF_POS_Y](../advanced_config/parameter_reference.md#EKF2_OF_POS_Y) and [EKF2_OF_POS_Z](../advanced_config/parameter_reference.md#EKF2_OF_POS_Z) can be set to account for the offset of the Ark Flow from the vehicle centre of gravity.
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When optical flow is the only source of horizontal position/velocity, then lowering the gain for controller response to horizontal position error [MPC_XY_P](../advanced_config/parameter_reference.md#MPC_XY_P) (e.g. to 0.5) is recommended to reduce oscillations.
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## Ark Flow Configuration
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On the ARK Flow, you may need to configure the following parameters:
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| Parameter | Description |
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| -------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------- |
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| <a id="CANNODE_NODE_ID"></a>[CANNODE_NODE_ID](../advanced_config/parameter_reference.md#CANNODE_NODE_ID) | CAN node ID (0 for dynamic allocation). If set to 0 (default), dynamic node allocation is used. Set to 1-125 to use a static node ID. |
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| <a id="CANNODE_TERM"></a>[CANNODE_TERM](../advanced_config/parameter_reference.md#CANNODE_TERM) | CAN built-in bus termination. |
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## LED Meanings
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- Solid blue is normal operation
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- Rapid blinking blue and red is firmware update
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If you see a solid red LED there is an error and you should check the following:
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- Make sure the flight controller has an SD card installed.
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- Make sure the Ark Flow has `ark_can-flow_canbootloader` installed prior to flashing `ark_can-flow_default`.
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- Remove binaries from the root and ufw directories of the SD card and try to build and flash again.
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## Video
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<lite-youtube videoid="SAbRe1fi7bU" params="list=PLUepQApgwSozmwhOo-dXnN33i2nBEl1c0" title="ARK Flow Indoor Position Hold x64"/>
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<!-- ARK Flow with PX4 Optical Flow Position Hold: 20210605 -->
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_PX4 holding position using the ARK Flow sensor for velocity estimation (in [Position Mode](../flight_modes_mc/position.md))._
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## See Also
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- [ARK Flow](https://arkelectron.gitbook.io/ark-documentation/sensors/ark-flow) (ARK Docs)
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