Bipedal Gait Planning Across Single and Double Support Phases

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Solution Overview

Problem

Two-legged robots exhibit poor walking stability due to reliance on center-of-mass state control during single support phase only, neglecting double support phase dynamics.

Innovation Solution

A motion control method that acquires gait parameters and inputs them into a gait planning model to determine gait trajectory parameters for both double and single support phases, including center-of-mass position and movement speed, to stabilize the robot's movement by combining both phases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the two-legged robot is controlled to walk based only on the center-of-mass state in the Single Support Phase, then the control system is simple, but the walking stability is poor

Engineering Contradiction:
Improvecontrol system complexityVSAvoidwalking stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The gait planning model is segmented into two distinct phases: Single Support Phase model and Double Support Phase model. Each phase has its own center-of-mass state parameters and control equations, allowing independent optimization of control strategies for each phase while maintaining overall system stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control system dynamically switches between Single Support Phase control and Double Support Phase control based on the robot's current gait phase. The center-of-mass state parameters are dynamically adjusted according to the phase transition, enabling adaptive control that maintains stability throughout the walking cycle.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If the gait planning model includes both Single Support Phase and Double Support Phase center-of-mass states, then the walking stability is improved, but the device complexity increases

Engineering Contradiction:
Improvewalking stabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The Single Support Phase model and Double Support Phase model are merged into a unified gait planning framework. The model seamlessly integrates both phases by using phase-specific center-of-mass state parameters and transition conditions, achieving improved stability without requiring completely separate control systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system changes parameters based on the gait phase: during Single Support Phase, it uses single-leg support parameters; during Double Support Phase, it uses dual-leg support parameters. This parameter switching allows the system to adapt to different mechanical configurations without increasing fundamental system complexity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4321417A1Motion control method and two-legged robot
Publication Date: 2024.02.14 BEIJING XIAOMI ROBOT TECH CO LTD
  • EP4321417A1 patent drawingFigure 1~3
  • EP4321417A1 patent drawingFigure 4~5
  • EP4321417A1 patent drawing

AI summary

A method for controlling motion of a two-legged robot includes: acquiring gait parameters of the two-legged robot; inputting the gait parameters to a preset gait planning model; determining gait trajectory parameters of the two-legged robot based on the gait parameters through the preset gait planning model, in which the gait trajectory parameters include a center-of-mass state corresponding to a double support phase and a center-of-mass state corresponding to a single support phase, and the center-of-mass state includes a center-of-mass position and a center-of-mass movement speed; and controlling the two-legged robot to move according to the gait trajectory parameters.