Humanoid Robot Gait Planning With Variable CoM Height
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current gait planning methods for humanoid robots, such as the Linear Inverted Pendulum Mode (LIPM), face challenges in increasing walking speed while maintaining stability, as they require constant center of mass height, leading to insufficient leg length during fast walking.
Innovation Solution
A variable-height LIPM model is introduced, where the height of the center of mass is reduced and its fluctuation is considered, allowing for decoupled vertical and horizontal movement, enabling effective leg length provision for fast walking by adjusting the height of the center of mass during the gait cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the LIPM-based gait planning method is used to maintain constant center of mass height, then walking stability is maintained, but leg length becomes insufficient during fast walking
Solution Approach 1:
The patent transforms the static constant-height LIPM model into a dynamic variable-height model where the center of mass height changes during the gait cycle. This allows the robot to achieve longer effective leg length during fast walking while maintaining stability through controlled height variation rather than fixed height constraint.
Solution Approach 2:
The patent changes the key parameter of center of mass height from a constant value to a variable parameter that fluctuates during walking. By introducing height reduction amplitude and fluctuation amplitude as controllable parameters, the system can adapt leg length to walking speed requirements while preserving stability through regulated parameter variation.
2Device complexity
If the center of mass height is kept constant in LIPM model, then the model simplicity is maintained, but walking speed increases are limited
Solution Approach 1:
The patent introduces dynamic height variation into the LIPM model, allowing the center of mass height to change during the gait cycle. This dynamic adjustment enables faster walking speeds by providing sufficient leg length, while the model remains relatively simple by building upon the existing LIPM framework rather than creating a completely new complex model.
3Speed
If leg length is increased for fast walking, then walking speed improves, but joint torque increases reducing efficiency
Solution Approach 1:
The patent changes the center of mass height parameter during the gait cycle to achieve longer effective leg length for fast walking. By reducing the center of mass height at appropriate phases, the system increases pressure on the supporting leg and reduces deflection amplitude, thereby improving walking speed while controlling joint torque through regulated height variation rather than permanent structural changes.
Data Source
AI summary
A gait planning method includes: performing a gait planning in each center of mass (CoM) timing period of the robot based on a variable-height linear inverted pendulum model, which includes: acquiring a first step length and a second step length at a beginning of each CoM timing period; calculating a first height reduction amplitude and a first fluctuation amplitude of the CoM of the robot according to the first step length; calculating a second height reduction amplitude and a second fluctuation amplitude of the CoM of the robot according to the second step length; and performing a planning to the height of the CoM of the robot in the current CoM timing period, based on the first height reduction amplitude, the first fluctuation amplitude, the second height reduction amplitude, and the second fluctuation amplitude.