Learning library
Understand how a robot works.
Build working knowledge of robotics and machine learning through examples you can change, calculations you can check, and data you can inspect.
Search for a specific concept, or follow a short path from an idea to its application.
126 lessons found
Foundations firstFoundations / 10 min read
Coordinate frames: read the same point from a robot and the world
Convert a fixed landmark between robot and world coordinates. Learn frame conventions, translation and rotation, inverse transforms, and point versus displacement.
Foundations / 12 min read
Rotation matrices: turn vectors, track frames, and check the order
Build rotation matrices that preserve length and handedness. Compare fixed-axis rotations in 3D, distinguish rotating a vector from changing its coordinates, and undo a rotation with its transpose.
Foundations / 12 min read
Homogeneous transformations: map sensor coordinates into the world
Combine rotation and translation in one matrix. Follow a sensor-to-robot-to-world frame chain, distinguish points from displacements, and calculate the inverse.
Foundations / 10 min read
Euler angles and gimbal lock: when different angles mean the same orientation
Explore roll, pitch, and yaw with full rotation matrices. Compare equivalent orientations at ±90° pitch and separate Euler angle rates from angular velocity.
Foundations / 12 min read
Axis-angle rotation: build Rodrigues’ formula from three vector terms
Rotate a vector around any nonzero axis. Normalize the direction, follow Rodrigues’ parallel and perpendicular terms, and understand the equivalent descriptions at zero and 180 degrees.
Foundations / 12 min read
Unit quaternions: compose rotations and understand the sign
Rotate vectors with Hamilton quaternions, check composition order, and see why q and minus q describe the same orientation. Includes an interactive experiment and Python.
Foundations / 10 min read
Derivatives and the chain rule: predict a small change
Understand derivatives as local rates, compare secant and tangent slopes, and multiply the correct factors through nested functions. Test a smooth curve and a corner with an interactive experiment.
Foundations / 13 min read
Partial derivatives and gradients: predict a multivariable change
Hold one input fixed to find a partial derivative, combine the partials into a gradient, and compare a directional derivative with the actual change from a finite step.
Foundations / 13 min read
Jacobian matrices: from joint rates to robot tip velocity
Read a Jacobian by its rows and columns, calculate a two-link arm's tip velocity, and compare a local prediction with a finite move. Includes singularities and the multivariate chain rule.
Foundations / 11 min read
Hessians: measure curvature in every direction
Differentiate a gradient to build the Hessian, calculate directional curvature, and classify stationary points. Explore coupled quadratics, saddles, and the limits of zero eigenvalues.
Foundations / 13 min read
Taylor expansion and linearization: predict locally and check the error
Build constant, linear, and quadratic approximations around a chosen center. Compare their errors, calculate a Taylor remainder bound, and connect the same idea to gradients, Hessians, and Jacobians.
Foundations / 12 min read
Ordinary differential equations: turn a rate law into a time course
Solve a cooling initial-value problem, compare its exact solution with Euler steps, and separate model behavior from numerical accuracy and stability.