Robot software

Robot Control Software

Disclaimer: Information that is presented here, might be deprecated.

Component owner: Anna, Marci
Date of assessment: 2016-05-10

Current status

• A state machine determines the control logic of the robot

  • Written in Yakindu

  • Main capabilities of the state machine

    • An automated, pre-defined control sequence can be initiated in a dedicated state. This complex sequence is decomposed of multiple states

    • When manual control is active, states express the action to be taken in a "do" statement. Events generated by the motors and the sensors fire the transition back to the "IDLE" state

  • The state machine contains some safety considerations

    • If the grabber crane is lifted, it cannot be opened

    • If the grabber crane is lowered, the arm cannot rotate around the basis

    • There are transitions for emergency events that drive the state machine to a "STOP" state, which is basically a deadlock

  • Sends high level commands

• Glue code consists of two main parts:

  • Glue code for MQTT

    • Publishes the messages to a designated MQTT topic

    • Subscribes to a given channel

  • Glue code for event and action translation

    • Converts messages to and from the protocol used by other components

    • Runs the code generated from the state machine

Issues and TODOs

• Due to the unreliable signals of the end-state sensors (touch sensors), occasionally the end states are not detected correctly. For this reason the initialization of the robot is a bit hacky (we can select if we want to skip the initialization step of the robot and set some values manually)

• Error handling is missing from the glue code

• Javadoc

• Basic documentation for the state machine

• Tests

• Use the MQTT broker of the table

  • Use QoS

  • Use retained messages in event driven devices to store latest state for devices subsribing later

• Logging and monitoring

Development directions:

• Decouple the glue code and the state machine code as much as possible

• Use hierarchical state machines

  • Also try to extract the glue code to state machines as much as possible

• Monitoring using the GUI of the state machine

• Anna: 1-2 month of work in the summer, potentially TDK

• Marci: 1-2 month of work in the summer, potentially TDK