1. Analog PID Controller
   • Materials
   • Circuit Description
   • Tuning Process
2. Digital PID Controller
   • Repository Content
   • Project Description
   • Requirements
   • Usage Instructions

The analog PID controller circuit uses the following components:

• Power Supply: 3.3V and 12V sources to power operational amplifiers and the DC motor.
• Operational Amplifiers (OpAmps): For implementing proportional, integral, and derivative blocks.
• DC Motor: The actuator controlled by the PID.
• Magnetic Encoder: Provides feedback for closed-loop control.
• Potentiometers:
  • RV1, RV2, RV3: 100kΩ potentiometers for adjusting proportional, integral, and derivative gains.
  • RV4: 10kΩ potentiometer for setting the reference signal.
• Resistors:
  • 10kΩ (R1–R5, R8–R12) for defining circuit constants and OpAmp gains.
  • 1kΩ (R6) for feedback.
  • 100kΩ (R7) for the integrative stage.
  • 100Ω (R13, R14) for limiting current in power transistors.
• Capacitors:
  • 470nF (C1, C2) for integral and derivative stages.
  • 10nF (C3) for motor signal filtering.
• Transistors:
  • TIP122 (Q1): Amplifies the control signal to drive the motor.
  • TIP127 (Q2): Complementary transistor for the same purpose.
• Oscilloscope: For visualizing and tuning system response.
• Protoboard and Jumpers: For circuit assembly and testing.

The analog PID controller is implemented using OpAmp circuits:

• Proportional: Adjusted using RV1.
• Integral: Configured with R7 and C1.
• Derivative: Configured with R7 and C2. Feedback from the magnetic encoder provides the position signal, which is compared to the reference set by RV4 to compute the error. The output signal drives the motor through the power transistors.

The controller gains (proportional, integral, and derivative) were tuned manually using the potentiometers while observing the response on an oscilloscope. Adjustments were made to achieve the desired performance criteria, such as settling time and overshoot.

Located in the Arduino folder:

• PRBS_Generator.ino: Generates a Pseudo Random Binary Sequence (PRBS) to collect system data.
• PID_Controller.ino: Implements the discretized PID controller with tuned gains for real-time motor control.

Located in the MATLAB folder:

• data_processing.m: Processes data collected by Arduino and saves it as a CSV file.
• system_identification.m: Identifies the system's transfer function using MATLAB's System Identification Toolbox.
• pid_tuner.m: Tunes the PID controller using MATLAB's PID Tuner.

This project extends previous work on the analog PID by implementing a digital PID controller for enhanced precision and flexibility. Feedback from the magnetic encoder is used to compute the error, and the controller adjusts the motor position accordingly.

To accurately model the system, a PRBS signal was used to excite the plant. The system's response was recorded, processed in MATLAB, and identified as a second-order transfer function with 99.35% reliability.

Using the identified transfer function, MATLAB's PID Tuner was employed to calculate the optimal gains ($K_p$, $K_i$, and $K_d$), which were implemented in the Arduino code.

• Arduino UNO or compatible microcontroller.
• MATLAB with System Identification and PID Control Toolboxes.
• Arduino IDE for compiling and uploading the code.
• Oscilloscope or Serial Plotter to monitor signals.

1. Clone this repository:

   git clone https://github.com/HumbertoBM2/AnalogAndDigitalPID.git