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Messages

This document details all of the messages that can be sent between the GUI and the MCU. We use the rdscom library to send these messages, if you want to learn more about the library, see the rdscom repository.

rdscom follows the idea of DataPrototypes, which describe how the data is structured (in key-value pairs). Each DataPrototype has a unique ID, which is used to identify the message. The GUI and the MCU both have a list of DataPrototypes that they can send and receive. These messages can be of type Request, Response, or Error. Some of these messages require acknowledgement, which is handled by the rdscom library.

DataPrototypes

DataPrototype 0 - Heartbeat

This message is used to check if the connection is still alive. The GUI sends a request to the MCU, and the MCU responds with an acknowledgement of type Heartbeat.

Message ID: 0
Fields:
    - `rand`: `int8` - A random number that the GUI generates to check if the connection is still alive
Acknowledgement: Yes

DataPrototype 1 - MotorControl

This message is used to control the motors. The GUI sends a request to the MCU, and the MCU responds with an acknowledgement of type MotorEvent. However, this action isn't instataneous, rather it adds the control to a queue, which is triggered by the ControlGo message.

Message ID: 1
Fields:
    - `motor_id`: `uint8` - The ID of the motor to control
    - `control_mode`: `uint8` - The control mode of the motor (0: position, 1: velocity, 2: torque)
    - `control_value`: `float` - The value to set the motor to
    - `simutaneous`: `bool` - Whether the control should be executed simutaneously with the previous control in the queue
Acknowledgement: Yes

DataPrototype 2 - MotorEvent

This message is used to send events from the MCU to the GUI. The MCU sends a response to the GUI after receiving a MotorControl message.

Message ID: 2
Fields:
    - `motor_id`: `uint8` - The ID of the motor that the event is for
    - `success`: `bool` - Whether the event was successful
    - `event_type`: `uint8` - The type of event (0: position, 1: velocity, 2: torque)
    - `event_value`: `float` - The value of the event
    - `num_in_queue`: `uint8` - The number of events in the queue
    - `executed_with_count`: `uint8` - The number of events executed with this event
Acknowledgement: No

DataPrototype 3 - ControlGo

This message is used to trigger the execution of the control queue. The GUI sends a request to the MCU, and the MCU responds with an acknowledgement of type ControlGo.

Message ID: 3
Fields:
    - `rand`: `int8` - A random number that the GUI generates to check if the connection is still alive
Acknowledgement: Yes

DataPrototype 4 - ControlDone

This message is used to send a response from the MCU to the GUI after the control queue has been executed. The MCU sends a response to the GUI after the control queue has been executed, and the GUI responds with an acknowledgement of type ControlDone.

Message ID: 4
Fields:
    - `success`: `bool` - Whether the control queue was executed successfully
    - `time`: `uint32` - The time it took to execute the control queue in milliseconds
    - `executed`: `uint8` - The number of events executed
Acknowledgement: Yes

DataPrototype 5 - StartSensorDatastream

This message is used to start the sensor datastream. The GUI sends a request to the MCU, and the MCU responds with an acknowledgement of type SensorDatastream.

Message ID: 5
Fields:
    - `joint_id`: `uint8` - The ID of the sensor to start the datastream for, 255 for all sensors
    - `frequency`: `uint8` - The frequency of the datastream in Hz
Acknowledgement: Yes

DataPrototype 6 - SensorDatastream

This message is used to send sensor data from the MCU to the GUI. The MCU sends a response to the GUI after receiving a StartSensorDatastream message.

Message ID: 6
Fields:
    - `joint_id`: `uint8` - The ID of the sensor that the data is for
    - `data`: `float` - The data from the sensor
Acknowledgement: No

DataPrototype 7 - StopSensorDatastream

This message is used to stop the sensor datastream. The GUI sends a request to the MCU, and the MCU responds with an acknowledgement of type SensorDatastream.

Message ID: 7
Fields:
    - `joint_id`: `uint8` - The ID of the sensor to stop the datastream for, 255 for all sensors
Acknowledgement: Yes

DataPrototype 8 - ClearControlQueue

This message is used to clear the control queue. The GUI sends a request to the MCU, and the MCU responds with an acknowledgement of type ClearControlQueue.

Message ID: 8
Fields:
    - `rand`: `int8` - A random number that the GUI generates to check if the connection is still alive
Acknowledgement: Yes

DataPrototype 9 - Error

This message is used to send an error message from the MCU to the GUI. The MCU sends a response to the GUI when an error occurs, and the GUI responds with an acknowledgement of type Error.

Message ID: 9
Fields:
    - `error_code`: `uint8` - The error code
Acknowledgement: Yes

DataPrototype 10 - Stop

This message is used to stop the motors. The GUI sends a request to the MCU, and the MCU responds with an acknowledgement of type Stop. This will override any control in the queue.

Message ID: 10
Fields:
    - `rand`: `int8` - A random number that the GUI generates to check if the connection is still alive
Acknowledgement: Yes

Usage

So, if we wanted to make the end effector move to a certain position, we would send the following messages:

  1. GUI sends a MotorControl message for all necessary motors to the MCU
  2. GUI sends a ControlGo message to the MCU
  3. MCU sends a ControlDone message to the GUI

If we wanted to start the sensor datastream for all sensors, we would send the following messages:

  1. GUI sends a StartSensorDatastream message to the MCU
  2. MCU sends a SensorDatastream message to the GUI for each sensor
  3. GUI sends a StopSensorDatastream message to the MCU