azfarus / ESP32_self_balancing_robot

A Self balancing bot based on ESP32 &MPU6050

Codes :

The self_balance_bot_code folder contains the actual code. Just install the libraries and the code is good to run. MPU6050_kalman folder has a primitive code based on the kalman filter library , but that was replaced in the actual code with a dynamic complementary filter.

Node-red flows :

flows.JSON contains the node-red flow configurations to interact with the mosquitto MQTT server setup on my local machine.

Fritzing Sketch :

The .fzz fritzing sketch of the bot is available. Only the schematic diagram is properly routed.

About the Dynamic Complementary Filter :

Normally the complementary filter combines the gyro and accelerometer values through a constant k & its complementary (1-k).

gyro_angle_x = (1 - k )*gyro_angle_x + k * acc_angle_x

But this filter can be unstable when arbitrary acceleration is introduced in the system and most of the times acceleration is hard to predict. Thus in the filter implementation I've done in my code dynamically reduces the constant k based on the acceleration and the change in acceleration. The function which varies the k constant is a bell curve i.e. $y=e^{b(x-c)^2}$ where b determines the slope of the decrement , c determines the calibrated value of acceleration/jerk where k should be maximum i.e the function returns 1.0 .