README.md

Robot Control using PID Controller and Kalman Filter

The objective is to estimate the Velocity using a Linear Kalman Filter and to control a robot using a PID Controller.

Consider a robot on frictionless, straight lane. Initially, the robot is stationary at position 0. We measure the position of the robot every $\Delta t$ seconds, but these measurements are imprecise; we want to maintain a model of the robot's position and velocity.

We show here how we derive the model from which we create our Kalman filter. Since $F$, $H$ , $R$ and $Q$ are constant, their time indices are dropped.

The position and velocity of the robot are described by the linear state space $x_k$ = [ $x$ , $v$ ] % $x$ : position ; $v$ : velocity

We assume that a(k) is unknown and normally distributed with mean 0 and standard deviation $\sigma_a$. From Newton's laws of motion we conclude that $$x(k) = F x(k-1) + G a(k)$$

We suppose there is no control inputs $G a(k)$ term, where $$F = [1 \quad Δt;0 \quad 1]$$ $$G = [Δt^2/2;Δt]$$

Then, a PID controller is used to generates the acceleration ( $a$ ) to control the robot's velocity ( $v$ ) using the estimated one ( $\tilde{v}$ ).

To try this example ...
1. Run the main.m file
2. A pop-up message will appear
3. Choose your tuning PID Controller parameter (by default Kp = 0.8 and Ki = 0.001)
4. That's it !