In the previous exercice we were drawing the outline of the robot based on the pair [math](A, \theta)[/math]. Now we are going to build a a simple script to animate the robot. The robot uses differential steering, which means the left motor runs at speed [math]v_0[/math] and the right motor at speed [math]v_1[/math]. From this we can calculate the forward speed [math]v_f=\frac{v_1+v_0}2[/math] and also the differential speed [math]v_d=\frac{v_1-v_0}2[/math] In order to animate the robot we add 3 buttons: - [b]Reset[/b], which sets [math]A=(0,0)[/math] and [math]\theta=0[/math] - [b]Start[/b], which starts the animation (StartAnimation[true]) - [b]Stop[/b], which stops the animation (StartAnimation[false]) We also add an animation script to the (invisible) time slider: A=A+v*v_f*dt θ=θ+ω dt Set two motor speeds [math](v_0, v_1)[/math] and press the [b]Start[/b] button. Observe the trajectory of the two wheels.

Try to create your own robot animation. Add buttons to turn left/right and other buttons to accelerate/decelerate.

How can simulate sensor input to change the behavior of our robot ? Use the position of the ground sensors and check if it falls within the boundaries of a rectangular area. For this we define two boolean values [math](out_0, out_1)[/math]to see if the sensor position [math](C_0, C_1)[/math] is inside the rectangle defined by the points [math](F_0, F_1)[/math] [math]out_0=(x(C_0) < x(F_0)) ∨ (x(C_0) > x(F_1)) ∨ (y(C_0) < y(F_0)) ∨ (y(C_0) > y(F_1))[/math] [math]out_1=(x(C_1) < x(F_0)) ∨ (x(C_1) > x(F_1)) ∨ (y(C_1) < y(F_0)) ∨ (y(C_1) > y(F_1))[/math] We use this information inside the animation script of the slider time [b]t[/b] to determine if the robot needs to turn. A=A+v*v_f*dt If[out_0, SetValue[θ, θ-dθ],If[out_1, SetValue[θ, θ+dθ]]] To give a visual feedback when the sensor is outside the rectangle, we momentarily increase the size from 3 to 15. SetPointSize[C_0, If[out_0, 15, 3]] SetPointSize[C_1, If[out_1, 15, 3]]