Research

Transitional Kinematics for Continuous Locomotion Control

A convex-combination kinematic model for powered knee-ankle prostheses that represents walking, stair movement, and the transitions between them in one continuous formulation. Plainly: this project built the motion model that later made smooth transition controllers possible.

IEEE TMRB 2022 Kinematic Modeling Continuous Transition Biomechanics Powered Prosthesis

TMRB 2022 Paper

Follow-up: Continuous Impedance Transition (TNSRE 2026) →

Conceptual formulation of the transitional kinematics model (TMRB 2022) — Transitional kinematics diagram linking steady-state stair and walk models through an alpha-blended transition formulation for walk-to-stair and stair-to-walk movement. Adapted from Cheng et al., IEEE TMRB 2022. © 2022 IEEE.

Problem & Contribution

The hardest moment in locomotion is often the transition itself; this work models walk–stair transitions as first-class movement, not just the gap between steady-state activities.

My Role

I developed the transitional kinematics formulation that modeled walking, stairs, and walk–stair transitions within a unified continuous framework.

Challenge

Discrete mode switching between walking and stairs is prone to timing errors and abrupt, uncomfortable transitions.

Contribution

A convex-combination movement model connecting walking, stair climbing, and walk–stair transitions.

Ph.D. research conducted in the LocoLab at the University of Michigan, advised by Prof. Robert D. Gregg.

Model Decomposition

1 Steady-State Primitives Walking and stair kinematics are captured as reference behaviors.
2 Convex Combination A weighted blend of primitives represents the in-between motion.
3 Transition Kinematics One continuous, differentiable model spans walk, stair, and transition.