Sunday, June 12, 2022

Zyderbot Architecture

 Zyderbot is very modular and the parts have been assembled to work together around ideas put in place early on in the competition. This is a brief overview of what it comprises. 


The central chassis, as described in previous blogs. houses the controller Raspberry Pi and it is this which forms the central control and communication hub of the robot. 

A VNC connection to this Pi is used to connect to it from a laptop and programming is done using the Python IDE or Thonny. The controller Pi also runs the camera, support for which is built into the Pi.

The rest of the robot platform is modularised to provide dedicated functions, there are two groups, the main chassis controllers and the attachment controllers. As this is our first entry into PiWars, we've designed something which is reusable and the design and code is on Github. 

The main controller runs a command queue, onto which commands can be placed, either from an onboard file, as running a script, from the command line as direct input, or as a response from a separate controller, which in this case is either a Pico or an ESP32.

For autonomous processing, the controller reads a script file and runs commands to either take actions or invoke further autonomous actions, such as running a trough filling hopper or picking an apple. 

A motion command will be sent to the Motor Controller Pico which measures distance and actuates the four chassis motors. 

For Remote Control operation, an ESP32 is used with a PS3 handheld controller to submit commands to the controller, which are passed onto the Motor Controller, providing the necessary control.

For audio input, a separate Pico is used to listen on a microphone, interpret the audio signals it receives, and then pass these on to the command queue.

The Camera is invoked by commands to enable seeking and following operations, itself issuing commands back to the queue to act on received information.

The attachment controllers are there to enable easy integration between the chassis and the attachments, running all the attachment motors, servos and sensors so relieving the main controller of that burden and providing a division of labour.

For each PiWars challenge, an attachment is provided, to a standard mounting specification, power supplied from the batteries as a nominal 12V and communication to the Pi controller is over USB, which also supplies controller power an enables coding on the attachment controller from the central Pi.

There's a lot of code around this, as well as some direct handshake signals to get the timing right, but it's a good platform to take forward into future projects and competitions.

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