Mobile & Legged Robotics

Two wheels, two motor commands, endless variations. The kinematics, the command conversion, the slip problem, and the 50 lines of code that control any diff-drive robot.

~13 min

Cars don't pivot. They turn around an instantaneous center, with both front wheels at different angles. The kinematic constraints, the bicycle-model approximation, and what changes for planners and controllers.

~13 min

Three-wheel and four-wheel omni kinematics. When you need holonomic motion, when you don't, and the mechanical price you pay for sliding sideways.

~11 min

Trot, bound, pace, gallop — four families of quadruped gait, each a different phase pattern. The phase diagram you'll see in every legged robotics paper, demystified.

~14 min

Zero Moment Point and Capture Point — the classical tools that kept Honda's ASIMO upright. Still useful in the era of learned gaits, and the lingua franca every humanoid team speaks.

~13 min

Hierarchical task control, friction cone constraints, the QP-based formulation every humanoid team uses. Turning a high-level plan into 25+ DOF of coordinated joint motion.

~14 min

Five years ago, every quadruped used hand-tuned MPC. Today they all use RL. Here's the recipe — domain randomization, action space choices, real-world deployment — that ate the field.

~13 min

The hierarchy that flies every quadrotor — three nested loops, each tuned for its timescale. PID for the rate loop, MPC for the trajectory, and the differential-flatness trick that makes it tractable.

~12 min

The perception → prediction → planning → control pipeline, mapped one level at a time. The architecture behind every L4 vehicle, with honest notes on what's still hard in 2026.

~14 min

The frontier where metric planning meets human behavior modeling. Personal space, intent inference, and the hard task of being a 'polite' robot in a crowded space.

~12 min