What are the key differences between PID and LQR controllers in robotic systems?

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What are the key differences between PID and LQR controllers in robotic systems?

Asked on Dec 25, 2025

Answer

PID and LQR controllers are both used for control in robotic systems, but they differ in their approach and application. PID (Proportional-Integral-Derivative) controllers are simpler and widely used for straightforward control tasks, while LQR (Linear Quadratic Regulator) controllers are more complex and optimal for systems where a model-based approach is feasible.

Example Concept: A PID controller adjusts the control input based on the error, its integral, and its derivative, making it suitable for systems with clear error dynamics. In contrast, an LQR controller uses a state-space model to minimize a cost function, balancing control effort and state deviation, which is ideal for systems where precise modeling and optimization are possible.

Additional Comment:

PID controllers are easier to implement and tune, often used in systems with less complexity and where quick deployment is needed.
LQR controllers require a mathematical model of the system, making them suitable for applications where system dynamics are well understood and can be accurately modeled.
LQR provides optimal control by minimizing a quadratic cost function, which can lead to more efficient control in terms of energy and performance.
PID is more intuitive and widely applicable, while LQR is more mathematically intensive and requires solving Riccati equations.

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