A compliant ankle-actuated compass walker with triggering timing control

2026-02-06

AI Summary

This work proposes a compliant ankle-actuated compass gait model with triggered timing control (TC-AACG) to overcome the limitations of conventional passive dynamic walkers, which rely on gravitational energy from slopes and struggle to walk efficiently on level or complex terrain. Departing from traditional impulsive energy injection and torsional spring mechanisms, the TC-AACG employs a non-instantaneous, compliant ankle push-off strategy based on series elastic actuators (SEAs), enabling a more engineerable bipedal locomotion mechanism. Simulation results demonstrate that the proposed approach significantly outperforms conventional designs on both flat ground and uneven terrain, achieving improvements in walking speed, mechanical cost of transport, and basin of attraction, thereby substantially enhancing the locomotor adaptability of bipedal models.

Technology Category

• Intelligent Robots: Motion and Path Planning
• Search and Optimization: Sampling/Simulation-based Search
• Humans and AI: Human-Aware Planning and Behavior Prediction

Application Category

• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs
• Search and Retrieval-Augmented AI: Agentic search
• User Modeling, Personalization and Recommendation: User modeling and simulation for interactive and conversational systems

Abstract

Passive dynamic walkers are widely adopted as a mathematical model to represent biped walking. The stable locomotion of these models is limited to tilted surfaces, requiring gravitational energy. Various techniques, such as actuation through the ankle and hip joints, have been proposed to extend the applicability of these models to level ground and rough terrain with improved locomotion efficiency. However, most of these techniques rely on impulsive energy injection schemes and torsional springs, which are quite challenging to implement in a physical platform. Here, a new model is proposed, named triggering controlled ankle actuated compass gait (TC-AACG), which allows non-instantaneous compliant ankle pushoff. The proposed technique can be implemented in physical platforms via series elastic actuators (SEAs). Our systematic examination shows that the proposed approach extends the locomotion capabilities of a biped model compared to impulsive ankle pushoff approach. We provide extensive simulation analysis investigating the locomotion speed, mechanical cost of transport, and basin of attraction of the proposed model.

Problem

• passive dynamic walking
• ankle actuation
• compliant actuation
• level ground locomotion
• bipedal walking

Innovation

• compliant ankle actuation
• triggering timing control
• series elastic actuators
• passive dynamic walking
• non-instantaneous pushoff