Getting the flywheels under control

After successfully building our launcher prototype, the next challenge was gaining control over the spinning wheels. To achieve this, we integrated motors with built-in speed sensors and utilized a Raspberry Pi for seamless interfacing.

Controlling Wheel Speeds with a Raspberry Pi:

We selected motors with built in speed sensors to allow us to access real-time feedback through a Raspberry Pi. This data provides feedback which can be used to control the wheel speeds effectively.

Implementation of a Basic P Controller:

Initially, we employed a basic Proportional (P) Controller. When the measured speed deviated from the desired speed, the control signal (in the form of Pulse Width Modulation - PWM - to the motor) was adjusted proportionally to the error (desired speed minus actual speed).

However, the initial results were suboptimal, showing inconsistencies and a struggle to maintain a consistent speed.

Refinement with PID Tuning:

To address these shortcomings, we explored PID tuning. The graph displayed a significant improvement - no overshoot, and the system efficiently maintained the desired speed. PID tuning introduced the elements of Integral and Derivative control to enhance overall performance.

Accurate Speed Control for Precision Launching:

The primary goal of achieving precise control over the wheel speeds is to ensure that both launcher wheels spin at the same rate. This uniformity is crucial for launching balls in a straight trajectory, eliminating any unwanted curves. Additionally, this level of control opens up the potential for future implementations, such as launching curveballs by varying wheel speeds precisely.

See our controller in action.

Conclusion:

Our journey from a basic P Controller to the refined PID tuning has significantly improved the control of launcher wheel speeds. This achievement ensures straight ball launches and opens the door to exploring more advanced techniques, such as introducing curveballs. As we continue to fine-tune our prototype, the precision and reliability of our launcher system take center stage in our pursuit of excellence.