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 / 12 min read
Numerical integration: compare drift, phase, and step cost
Advance an oscillator with forward Euler, velocity-first symplectic Euler, and classical RK4. Compare each method with the analytic solution and separate energy drift, phase error, step cost, and stability.
Foundations / 13 min read
ODE stability: equilibria, attraction, and basins
Classify equilibria of a nonlinear rate law, use a phase line to find basins of attraction, and compare exact trajectories without confusing model stability with numerical stability.
Foundations / 12 min read
Manifolds and tangent spaces: move along a constraint
Use the unit circle to understand local coordinates and tangent vectors. Compare straight steps, exact rotation, and normalization, then examine why averaging headings and rotations needs care.
Foundations / 13 min read
Geodesics: shortest arcs and longer routes on a circle
Compare a shortest circle arc, a longer constant-speed geodesic, and a straight chord. Work through angle wrapping, antipodal ties, coincident endpoints, and the metric that defines distance.
Foundations / 12 min read
Lie groups and Lie algebras: connect robot poses to local motions
Use planar robot poses to understand SE(2), its tangent space se(2), and the Lie bracket. Compare motion order, shrink a commutator loop, and reproduce the calculations in Python.
Foundations / 13 min read
Exponential and logarithm maps: turn a body twist into a pose
Exponentiate a constant planar body twist, calculate its coupled translation, and recover a chosen logarithm. Explore straight-motion limits, half-turn branch choices, and information lost in a full turn.
Foundations / 13 min read
Twists and screw axes: connect point velocities to rigid motion
Build a six-component twist from a screw axis, calculate point velocities, and compare exact helical motion with a tangent prediction. Separate pitch, accumulated displacement, current rate, and pure translation.
Foundations / 12 min read
Adjoint transformations: express a twist in another frame
Transform angular-first twists between body and space frames. Derive the origin-shift term, distinguish linear twist coordinates from point velocity, and check a planar example with an interactive adjoint matrix.
Foundations / 14 min read
Product of exponentials: build a robot arm’s forward kinematics
Build a two-joint arm's tool pose from fixed home screw axes and matrix exponentials. Check the result against geometry, inspect multiplication order, and connect space and body formulas.
Foundations / 14 min read
Wrenches: combine force, moment, and power across frames
Calculate a force's moment about a chosen origin, include a free couple, and transform a moment-first wrench between frames. Use a worked planar load to check the inverse-transpose rule and power invariance.
Foundations / 14 min read
Space and body Jacobians: map joint rates to rigid motion
Build space and body Jacobians from joint screw axes, recover the physical tool velocity, and compare their ranks with a position-only task. Explore a planar two-link arm and verify its derivatives in Python.
Foundations / 14 min read
Robot statics: turn tool loads into holding torques
Use virtual work and a Jacobian transpose to calculate a robot arm's joint loads. Distinguish external and holding torque, check space and body frames, and interpret zero-torque loads.