https://github.com/devbd1/pid_controlled_liquid_transfer
A PID controlled liquid transfer system. Built with an Arduino Uno, an HC-SR04, a 12V pump and an L298N H bridge for PWM control; using Octave (MATLAB .m program).
https://github.com/devbd1/pid_controlled_liquid_transfer
arduino arduino-uno matlab matlab-gui matlab-script octave octave-gui octave-scripts
Last synced: about 1 month ago
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A PID controlled liquid transfer system. Built with an Arduino Uno, an HC-SR04, a 12V pump and an L298N H bridge for PWM control; using Octave (MATLAB .m program).
- Host: GitHub
- URL: https://github.com/devbd1/pid_controlled_liquid_transfer
- Owner: DevBD1
- License: gpl-3.0
- Created: 2025-05-30T12:49:57.000Z (about 1 year ago)
- Default Branch: main
- Last Pushed: 2025-06-04T14:03:32.000Z (12 months ago)
- Last Synced: 2025-06-30T14:43:30.816Z (11 months ago)
- Topics: arduino, arduino-uno, matlab, matlab-gui, matlab-script, octave, octave-gui, octave-scripts
- Language: MATLAB
- Homepage:
- Size: 5.22 MB
- Stars: 1
- Watchers: 0
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
YouTube Video: https://www.youtube.com/watch?v=1OjPXJKbuPw
# Introduction
This project involves **two liquid-filled reservoirs**, labeled **A and B**. Reservoir A serves as a supply tank, and its liquid level is not critical. Reservoir B, however, requires a stable liquid level, which is the primary control objective. An ultrasonic distance sensor is mounted vertically above Reservoir B to measure the liquid depth, providing distance readings denoted as x₁. A **peristaltic liquid pump** connects the two reservoirs. The pump's role is to transfer excess liquid from Reservoir B to Reservoir A or to draw liquid from Reservoir A to replenish Reservoir B, depending on the measured liquid level.
# 📐 PID Control
To maintain the desired liquid level in Reservoir B, a PID (Proportional-Integral-Derivative) control algorithm is implemented. The controller minimizes the error between the setpoint and the measured value by adjusting the pump's operation.
The PID control law is defined as:
```
u(t) = Kp * e(t) + Ki * ∫e(t)dt + Kd * de(t)/dt
```
**Where:**
- ```e(t)``` is the error between the measured and target level (e.g., e(t) = x₁ - target)
- ```Kp``` is the proportional gain
- ```Ki``` is the integral gain
- ```Kd``` is the derivative gain
- ```u(t)``` is the output used to determine the pump’s direction and speed (via PWM)
This PID controller ensures that the liquid level in Reservoir B remains stable despite disturbances or changes in system dynamics.
---
# ✅ Requirements
#### Software
- [GNU Octave](https://www.gnu.org/software/octave/) (Tested on version 10 (2025-03-25))
- [Arduino IDE](https://www.arduino.cc/en/software) (Tested on version 1.8.19 (Store 1.8.57.0))
- USB connection to Arduino board (Uno, Nano, etc.)
- `instrument-control` package for Octave
#### Hardware
- Arduino Uno
- HC-SR04: Ultrasonic Sound Sensor
- L298N: H BRIDGE
- 12V 3x5 PUM: Peristaltic Water Pump
- 12V ADAPTER: Power Supply for the Pump
- 9V BATTERY: Power Supply for Arduino
#### Connection Map
Here is the connection map of the system:
COMPONENT | DESCRIPTION | COMPONENT PIN | CARD PIN | CARD
--- | --- | --- | --- | ---
HC-SR04 | Ultrasonic Sound Sensor | TRIG | D6 | UNO
HC-SR04 | Ultrasonic Sound Sensor | ECHO | D7 | UNO
L298N | H BRIDGE | IN1 | D8 | UNO
L298N | H BRIDGE | IN2 | D9 | UNO
L298N | H BRIDGE | ENA | D10 (PWM) | UNO
12V ADAPTER | POWER SUPPLY | + / - | L298N
12V 3x5 PUMP | Peristaltic Water Pump | + | OUT1 | L298N
12V 3x5 PUMP | Peristaltic Water Pump | - | OUT2 | L298N
---
# 🛠️ Installation
Follow the steps below to set up the environment for PID-controlled liquid transfer.
### 📦 Octave Setup
1. Install the `instrument-control` package:
```octave
pkg install -forge instrument-control
pkg load instrument-control
```
2. Clone this repository or download the source code:
```bash
git clone https://github.com/DevBD1/PID_Controlled_Liquid_Transfer.git
cd PID_Controlled_Liquid_Transfer
```
3. (Optional) If you have `.env` or calibration constants, place them in the root folder.
4. Make sure your Arduino is connected via `COM3` or change the port in the script:
```matlab
s = serialport("COM3", 9600);
```
### 🔌 Arduino Upload
1. Open [`arduino/transfer_serial.ino`](https://github.com/DevBD1/PID_Controlled_Liquid_Transfer/blob/main/arduino/transfer_serial.ino) in Arduino IDE.
2. Select your correct board and COM port.
3. Upload the sketch.
### 🧪 First Start
To test the system and determine the standard deviation of sensor inputs:
1. Run [`matlab/standard_deviation/log_realistic.m`](https://github.com/DevBD1/PID_Controlled_Liquid_Transfer/blob/main/matlab/standard_deviation/log_realistic.m) script
2. Input the direction of the pump for test
3. Input the repeat count
4. Check the generated .csv file
5. Run [`matlab/standard_deviation/analyse.m`](https://github.com/DevBD1/PID_Controlled_Liquid_Transfer/blob/main/matlab/standard_deviation/analyse.m) script
6. Read the output, the script will generate a variable at the end
7. Check the generated `pid_tolerance.mat` file
To start full PID control:
1. Run [`matlab/pid_control_serialport_mapped.m`](https://github.com/DevBD1/PID_Controlled_Liquid_Transfer/blob/main/matlab/pid_control_serialport_mapped.m) script
```octave
pid_control_serialport_mapped.m
```
---
# ⚙️ Configuration
You can modify the PID constants and port settings at the top of the `.m` files:
```matlab
Kp = 40;
Ki = 0.5;
Kd = 20;
s = serialport("COM3", 9600); % Change if needed
```
Use log_static.m when the reservoir B is empty. The result is your max. height.
# 🧪 Other Scripts
- ```Fill or Empty``` -> dir: [.../matlab/fill_or_empty.m](https://github.com/DevBD1/PID_Controlled_Liquid_Transfer/blob/main/matlab/fill_or_empty.m)
- ```Stop``` -> dir: [.../matlab/stop.m](https://github.com/DevBD1/PID_Controlled_Liquid_Transfer/blob/main/matlab/stop.m)