Biped Robot Leg Length Adjustment for Uneven Terrain Stability
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Solution Overview
Problem
Biped robots face challenges in maintaining walking stability on uneven terrain, as existing control methods often fail to adapt effectively to changes in height, leading to potential falls.
Innovation Solution
A control method that adjusts leg lengths in real-time during the double-support phase based on a capture point, using a Linear Inverted Pendulum Model to calculate desired support forces and distribute them between legs, allowing the robot to maintain stability by adapting to uneven surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing robot control methods are used, then the robot can walk on even surfaces, but the robot cannot maintain stability on uneven terrain
Solution Approach 1:
The patent applies dynamics by making the leg length adjustable rather than fixed. During the double-support phase, the controller dynamically changes the length of the left and right legs based on the detected height difference between the two feet, allowing the robot to adapt to uneven terrain while maintaining stability. This dynamic adjustment resolves the contradiction by enabling the robot to both walk on even surfaces and adapt to uneven terrain.
Solution Approach 2:
The patent changes the parameter of leg length to resolve the contradiction. By detecting the height difference between left and right feet and adjusting the respective leg lengths accordingly, the robot can maintain a stable upright pose on uneven terrain. This parameter change enables the robot to adapt to different terrain conditions while preserving walking stability.
2Reliability
If the robot adjusts leg lengths to adapt to uneven terrain, then walking stability improves, but control complexity increases
Solution Approach 1:
The patent implements feedback by using a sensor to detect the actual height difference between the left and right feet, then using this information to adjust the leg lengths. The controller receives feedback from the sensor about the terrain condition and automatically adjusts the leg lengths to maintain stability. This feedback mechanism resolves the contradiction by providing an automated, sensor-driven control approach that reduces manual intervention while maintaining stability.
Solution Approach 2:
The robot performs self-service by automatically detecting its own terrain condition through foot height detection and autonomously adjusting its leg lengths without external intervention. The system uses its own sensors and control mechanisms to adapt to uneven terrain, reducing the need for complex external control systems or manual adjustment.
Data Source
AI summary
A control method for a robot includes: determining a desired zero moment point (ZMP) of the robot; obtaining a position of a left foot and a position of a right foot of the robot, and calculating desired support forces of the left foot and the right foot according to the desired ZMP, the positions of the left foot and the right foot; obtaining measured support forces of the left foot and the right foot, and calculating an amount of change in length of the left leg and an amount of change in length of the right leg according to the desired support forces of the left foot and the right foot, the measured support forces of the left foot and the right foot; and controlling the robot to walk according to the amount of change in length of the left leg and the right leg.