Flight Computer Controls

System Design

Flight Detection System

Rocket Club

Thruster Design

Flight Computer

Control Strategy Goals

The requirement for the competitions states:

At motor burnout, the thrusters shall increase the rocket’s roll rate from 0 revolutions per minute (rpm) to 120 rpm, maintain 120-240 rpm for 3 seconds, then decrease to 0 rpm before apogee.

Since this system needs to maintain a spin rate within a large margin, the control scheme can be kept simple, using only the proportional terms of a PID function.

PWM Control Simulation

Originally we wanted to use PWM as the main control parameter to allow for the system to create an analog thrust signal from a digital thrust. unfortunately, I was under a major time crunch so I switched to a logic based Control system that functioned the same, but used Boolean PD logic gates to activate the thrusters

PWM PD Model Diagram

PWM PD Model Simulation

Testing

Open Loop Control Test - Success

This video is the first test for the cold gas system. I decided to use an open loop control strategy where it opens the counter clockwise valve for 5 seconds and then reverses the direction for 4 seconds. The graph bellow is the results of the gyroscope data.

First Close Loop Control Test - Failure

This was the first closed loop control test. This test failed due to timing issues (where a parameter was in milliseconds rather then Seconds) and the system turned on the wrong direction to slow down.

Closed loop Control Test - Success

This was the 8th test and a complete success once the bugs were fix. Below is the data from this test with some visual goal posts of the RPM set points for the control systems.

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