Robotic Arm

The location ( x , y ) can be computed as ( L₁cos(θ₁) + L₂cos(θ₂ ) , L₁sin(θ₁) + L₂sin(θ₂ ) ) using forward kinematics, but in most practical problems you know the desired location ( x , y ) and need to compute the rotation angles θ₁ and θ₂. To do this we must use inverse kinematics as is shown in the graph below.

UNIT PROJECT CHECKLIST

Drag the X and Y sliders below to see Inverse Kinematics in Action!

Arduino Math

The math required to compute the servo angles for inverse kinematics is basic geometry. The particular areas of geometry used include SOH CAH TOA , the Pythagorean Theorem , The Straight Angle Theorem, The Angle Addition Theorem, and The Law of Cosines. To perform this math in an Arduino sketch we use functions from the math.h C++ library. This library is automatically included in all Arduino sketches because it is required in the void loop() function. A reference to this library can be found here. In the sketch running in the simulation below you can see the computation and Serial console display of the two servo angle required to achieve a particular robotic hand position ( X , Y ).

Click the "Code" . Inspect the code. Close the code editor. Click "Start Simulation".

Designing Presentation Slides

Four Slide Template for Applied Geometry Slides

Some Sample "Context" Slides