Legged Robot Stair Climbing With Safe Step Region Foot Placement
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Solution Overview
Problem
Robots face challenges in safely and efficiently traversing stairs due to the need for precise leg movement and foot placement, which is difficult to coordinate without natural coordination.
Innovation Solution
A method and system for a robot to negotiate stairs by receiving image data, determining step regions for safe leg placement, shifting weight distribution, and moving the swing leg to a target step location within the step region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the robot uses precise leg movement and foot placement control to traverse stairs, then the robot can avoid collisions and improve safety, but the coordination complexity and control difficulty increase significantly
Solution Approach 1:
The patent segments the stair traversal task into distinct phases (swing phase and stance phase) and separate control components (weight distribution control, leg movement control, foot placement control). This segmentation allows each component to be controlled independently, reducing the overall coordination complexity while maintaining safety through systematic control of each segment.
Solution Approach 2:
The patent applies preliminary action by shifting the robot's weight distribution towards the front portion before the swing leg moves to the target step location. This preliminary weight shift prepares the robot's center of mass for the upcoming leg movement, ensuring stable foot placement and reducing the coordination burden during the actual stepping action.
2Stability of the object's composition
If the robot shifts weight distribution towards the front portion before moving the swing leg, then the robot improves stability during stair traversal, but the traversal time and operational complexity increase
Solution Approach 1:
The patent implements periodic action through alternating swing and stance phases for each leg. The weight distribution shifts periodically in coordination with the leg movement cycles, creating a rhythmic pattern that maintains stability while enabling continuous forward progression. This periodic coordination reduces the perceived traversal time by establishing an efficient gait cycle.
Solution Approach 2:
The patent ensures continuity of useful action by overlapping the weight distribution adjustment with the leg movement execution. Rather than completing weight shift entirely before leg movement begins, the system maintains continuous adjustment throughout the traversal, ensuring stability is preserved while minimizing idle time and maximizing forward progress.
Data Source
AI summary
A method for negotiating stairs includes receiving image data about a robot maneuvering in an environment with stairs. Here, the robot includes two or more legs. Prior to the robot traversing the stairs, for each stair, the method further includes determining a corresponding step region based on the received image data. The step region identifies a safe placement area on a corresponding stair for a distal end of a corresponding swing leg of the robot. Also prior to the robot traversing the stairs, the method includes shifting a weight distribution of the robot towards a front portion of the robot. When the robot traverses the stairs, the method further includes, for each stair, moving the distal end of the corresponding swing leg of the robot to a target step location where the target step location is within the corresponding step region of the stair.