Legged Robot Stair Traversal With Safe Step Region Planning
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Solution Overview
Problem
Robots lack the natural coordination to navigate stairs or stair-like terrain, leading to potential missteps, slips, trips, or falls, and existing technologies do not effectively provide precise leg movement and foot placement to avoid collisions.
Innovation Solution
A robot system that includes a traversal system with a controller, path generator, step planner, and body planner, utilizing sensor data to determine safe step regions and adjust weight distribution and body posture to navigate stairs, while detecting and responding to potential collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a robot uses conventional leg movement control to navigate stairs, then the robot can move forward, but it lacks precise foot placement capability leading to missteps, slips, trips, or falls
Solution Approach 1:
The navigation system is divided into multiple specialized modules: a path generator that creates overall navigation paths, a step planner that breaks down stair navigation into individual step actions, and a body planner that coordinates body movements. This segmentation allows each module to specialize in specific aspects of stair navigation, improving overall reliability without overwhelming the control system.
Solution Approach 2:
The step planner determines target step locations and safe step regions before the robot attempts to traverse each stair. The body planner pre-adjusts weight distribution and body posture in anticipation of upcoming steps. This preliminary planning ensures precise foot placement and prevents missteps by preparing the robot's configuration in advance.
2Manufacturing precision
If the robot adjusts weight distribution and body posture for precise stair navigation, then foot placement accuracy improves, but the control system complexity increases
Solution Approach 1:
The controller integrates multiple functions into a unified system that can generate paths, plan steps, plan body movements, and adjust weight distribution using the same hardware platform. This multi-functional approach achieves precise foot placement without requiring separate dedicated systems for each function, thereby limiting the increase in overall system complexity.
Solution Approach 2:
The system uses sensor data to detect the robot's current position, orientation, and weight distribution, then feeds this information back to the path generator, step planner, and body planner. This closed-loop feedback enables real-time adjustments to maintain precise foot placement while adapting to actual conditions, reducing the need for overly complex open-loop control mechanisms.
3Object-affected harmful factors
If the robot uses simplified navigation control, then the control system remains simple, but the robot cannot avoid collisions with stairs or obstacles
Solution Approach 1:
The step planner identifies safe step regions that are predetermined to avoid collision with stair structures. The body planner adjusts the robot's posture and weight distribution in advance to prevent collisions during leg movement. By taking anti-collision actions beforehand rather than reacting to collisions after they occur, the system reduces collision risk without requiring complex real-time collision detection and response mechanisms.
Data Source
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AI summary
A method (500) for negotiating stairs (20) includes receiving image data (164) about a robot (100) maneuvering in an environment (10) with stairs. Here, the robot includes two or more legs (104). Prior to the robot traversing the stairs, for each stair, the method further includes determining a corresponding step region (220) based on the received image data. The step region identifies a safe placement area on a corresponding stair for a distal end (106) 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. 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.