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Inverse Kinematics

Wheelchair Planning ships two IK backends behind a single factory (create_ik_solver):

  • TRAC-IK — fast numerical IK. Runs SQP and a pseudoinverse solver concurrently and returns the first valid solution. Best for unconstrained point-to-point targets.
  • Pink — differential QP IK. Composes an end-effector task with any number of soft secondary objectives (CoM, posture, camera, self-collision). Best when the solution must satisfy extra task-space invariants.

Both backends cover the same kinematic chains:

Chain DOF Span
arm 7 xArm7, link_base → link_tcp
whole_body 10 planar base + arm, Link_Zero_Point → link_tcp

Pick the chain with create_ik_solver("chain_name", ...) — see the JOINT_GROUPS table in wheelchair_planning.wheelchair for the mapping into the full 10-DOF body configuration.

  • Unconstrained IK (TRAC-IK)

    One call per target. Fast, thread-safe, deterministic under a fixed seed. Use when you have a reachable pose and want a solution.

  • Constrained IK (Pink)

    QP solve per step. Compose the end-effector task with CoM stability, camera stabilization, self-collision avoidance, and posture regularization.