This is my homemade Ball & Plate system.

System consist of 2 digital servo motors (Hitec HS-7955TG Ultra Torque), microcontroller Arduino MEGA 2560, and 4 wire resistive touchscreen (7"). There is Linear-Quadratic (LQ) regulator with Kalman filter working as Linear-quadratic estimator (LQE). This system can move any ( heavier ) round element to any point of the surface to an accuracy of ± 1 mm .

High-Precision Control Theory Application

The Ball and Plate System is a classic mechatronics challenge that demonstrates advanced control theory in a physical environment. Unlike simple balancing projects, this system utilizes a Linear-Quadratic (LQ) Regulator to achieve extreme stability and precision. It essentially solves a dynamic physics problem in real-time: how to tilt a plane so that a sphere remains at a specific X,Y coordinate despite gravity and initial momentum.

Hardware Infrastructure & Feedback Tier

• Arduino Mega 2560: Functions as the heavy-duty analytical core. Its high memory and multiple hardware timers are essential for running the complex floating-point math required for state estimation.
• 7-inch Resistive Touchscreen: The primary feedback sensor. By measuring the voltage changes when the ball (a conductive or heavy object) touches the surface, the system determines the ball's exact position with millimetric accuracy.
• Hitec HS-7955TG Servos (x2): The "Physical Actuators." These high-torque digital servos provide the fine-grained mechanical resolution needed to tilt the plate in minute increments.
• The Mechanical Linkage: Translates the rotational motion of the servos into the 2-axis tilting of the plate.

System Intelligence: LQ and Kalman Filtering

The "Magic" of this project lies in its sophisticated software stack:

1. The Kalman Filter (LQE): The raw data from a resistive touchscreen is often "noisy." The Kalman Filter acts as an optimal estimator, predicting the ball's position while filtering out electrical interference.
2. State-Space Modeling: The system describes the physical state (Position, Velocity, and Tilt) as a set of linear equations.
3. LQ Regulator Logic: Based on the current state, the LQ regulator calculates the optimal gain to minimize the "cost function"—effectively finding the most efficient and stable way to move the plate to balance the ball.
4. Precision Output: The resulting commands are sent to the servos at a high refresh rate, resulting in a system that can balance a ball with an accuracy of ±1 mm.

Why This Project is Important

Building a Ball and Plate system is a major milestone for any robotics engineer. it bridges the gap between basic DIY projects and industrial-grade automation. It teaches the principles of Dynamic System Modeling, Statistical Noise Filtering, and Optimization Algorithms. Successfully completing this project proves a deep understanding of how to control unpredictable physical variables with extreme mathematical precision.