Biped Robot COM Trajectory Control with Real-Time Correction
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Solution Overview
Problem
Conventional methods for controlling the trajectory of a biped humanoid robot's center of mass are complex and time-consuming, requiring re-planning when task modifications are needed, which complicates the process.
Innovation Solution
A method that divides the walking process into multiple gait cycles, using a simplified linear inverted pendulum model to plan and correct the center of mass trajectory in real time, allowing for rapid adjustments to new task requirements through cubic polynomial curve fitting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex motion equations or curves are constructed to pre-plan the center of mass trajectory according to task requirements, then the walking stability of the robot is ensured, but the re-planning process becomes complicated and time-consuming when tasks need to be modified
Solution Approach 1:
The patent segments the center of mass trajectory planning into periodic gait cycle segments. Each gait cycle is planned independently using a simplified periodic trajectory model, allowing individual cycles to be adjusted without re-planning the entire trajectory. This segmentation enables rapid task modifications by only adjusting the relevant gait cycle parameters while maintaining overall walking stability.
Solution Approach 2:
The patent changes the planning approach from complex motion equations to a simplified periodic trajectory model with adjustable parameters. By using parameters such as amplitude, frequency, and phase offset that can be easily modified, the system achieves rapid re-planning when tasks change, while the periodic nature ensures walking stability is maintained.
2Manufacturing precision
If complex motion equations are used to pre-plan the center of mass trajectory, then accurate trajectory control is achieved, but the control process becomes complicated
Solution Approach 1:
The patent extracts the essential characteristics of center of mass trajectory from complex motion equations, retaining only the critical periodic patterns needed for stable walking. By using a simplified periodic trajectory model that captures the fundamental motion patterns, the system achieves adequate trajectory control accuracy while dramatically reducing control process complexity.
Solution Approach 2:
The patent introduces dynamic adjustment capabilities to the periodic trajectory model, allowing real-time modification of trajectory parameters based on task requirements and robot state feedback. This dynamic approach maintains trajectory control accuracy by adapting to changing conditions while keeping the control process simple through the periodic model structure.
Data Source
AI summary
A method for controlling a robot based on a trajectory of a center of mass (COM) of the robot includes: calculate a desired periodic trajectory of the robot in a single gait cycle based on a dynamic equation constructed according to a simplified model of the robot; correct the desired periodic trajectory according to a fed-back state of the COM of the robot; generate a desired trajectory of the COM of the robot using the corrected desired periodic trajectory; and control motion of the robot according to the desired trajectory of the COM of the robot.