Contact-Anchored Proprioceptive Odometry for Legged and Wheel-Legged Robots
For legged robotics, this work provides a robust, drift-free odometry solution that eliminates reliance on external sensors, addressing a key bottleneck in autonomous navigation.
This paper presents a purely proprioceptive state estimator for legged and wheel-legged robots that uses only IMU and motor measurements to estimate body pose and velocity, achieving drift-free odometry without cameras or LiDAR. The method is validated on four quadruped platforms, demonstrating effective drift suppression and accurate pose estimation.
Reliable odometry for legged robots without cameras or LiDAR remains challenging due to IMU drift and noisy joint velocity sensing. This paper presents a purely proprioceptive state estimator that uses only IMU and motor measurements to estimate body pose and velocity, with a unified formulation applicable to quadruped and wheel-legged robots and extensible to other legged morphologies. The key idea is to treat each reliable contact as a kinematic anchor: joint-torque--based foot wrench estimation selects stance contacts, and the corresponding footfall records provide intermittent world-frame constraints that suppress long-term drift. To prevent elevation drift during extended traversal, we introduce a lightweight height clustering and time-decay correction that snaps newly recorded footfall heights to previously observed support planes. For wheel-legged platforms, the recorded contact is further propagated by effective wheel rolling displacement with shank-motion compensation and a slope-aware rolling direction. To improve foot velocity observations under encoder quantization, we retain an inverse-kinematics cubature Kalman filter as an optional velocity-enhancement module that filters foot-end velocities from joint angles and velocities. The implementation further mitigates yaw drift through multi-contact geometric consistency, which is injected as a soft heading prior rather than as a hard reset of the attitude state. The method is evaluated on four quadruped platforms.