apt-a1 · motion library · sagittal SRBD

A1 gait library viewer

Periodic trot and bound cycles from the reconstructed APT-RL generator, retargeted to our Unitree A1. Every frame below is real solver output — body pose from the SRBD cycle, legs drawn by forward kinematics from the stored joint angles, leg colour showing joint torque against the 33.5 N·m limit.

—µs / trajectory
1e−15periodicity residual
48–53%pass A1 limits
14.5 kgmeasured mass
0.377 mleg reach cap
0.000 s
stance (loaded) swing COM path torque 33.5 N·m

Time-aligned readouts — one full gait period

Contact schedule
Vertical ground reaction force
Joint torque

Reading it. Trot projects to front and rear contacts in phase, so the sagittal pattern repeats every half period and each contact carries one leg. Bound puts the front pair against the rear pair over the full period, two legs per contact — which is why the same 33.5 N·m ceiling bites at very different speeds in the two gaits.

What is synthesised. Stance comes from the solver. Swing carries no ground force, so the SRBD problem says nothing about it — those arcs are interpolated between footholds and clamped to 0.98 × reach. Stance is never clamped, so an infeasible stance is rejected rather than quietly fixed.