Robot Swing-Leg Impact Detection for Touchdown and Trip Response
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Solution Overview
Problem
Robots face challenges in accurately detecting footstep contact and trips, which can lead to instability and potential falls, especially when they fail to anticipate ground impacts during movement.
Innovation Solution
A method for footstep contact detection in robots, which involves receiving joint dynamics for the swing leg and odometry data to determine if an unexpected torque corresponds to an impact. The system classifies the cause of the impact, distinguishing between touchdown and other conditions like trips, to generate appropriate responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the robot uses traditional contact detection methods, then the system complexity is low, but the detection precision and reliability are insufficient leading to missed footstep contacts and trips
Solution Approach 1:
The detection system is segmented into multiple independent detection modules: torque sensor detection, odometry-based detection, and inertial measurement detection. Each module independently monitors different aspects of leg motion and contact forces, allowing the system to achieve high detection precision through multiple specialized sensors rather than a single complex sensor system.
Solution Approach 2:
The control system integrates multiple detection methods into a unified control architecture that handles both footstep contact detection and trip detection using the same sensor suite (torque sensors, odometry, inertial sensors). This multi-functional approach allows the system to detect different types of contacts (ground contact, object contact, self-contact) using a single integrated system, improving precision without proportionally increasing complexity.
2Speed
If the robot responds immediately to all detected impacts, then the response speed is high, but the stability deteriorates due to false positives from normal gait variations
Solution Approach 1:
The control system continuously monitors torque sensor data, odometry, and inertial measurements to detect impacts. When an impact is detected, the system generates feedback signals that trigger appropriate responses (pausing swing phase, adjusting gait parameters). This closed-loop feedback mechanism allows the system to respond quickly to genuine impacts while using continuous monitoring to distinguish real impacts from normal gait variations, maintaining stability.
Solution Approach 2:
The control system dynamically adjusts gait parameters based on detected impacts. When an impact is detected during swing phase, the system dynamically modifies the swing phase timing and leg trajectory to accommodate the unexpected contact. This dynamic adaptation allows rapid response to impacts while maintaining overall gait stability by adjusting parameters in real-time rather than using fixed rigid control.
Data Source
AI summary
A method of footstep contact detection includes receiving joint dynamics data for a swing phase of a swing leg of the robot, receiving odometry data indicative of a pose of the robot, determining whether an impact on the swing leg is indicative of a touchdown of the swing leg based on the joint dynamics data and an amount of completion of the swing phase, and determining when the impact on the swing leg is not indicative of the touchdown of the swing leg, a cause of the impact based on the joint dynamics data and the odometry data.