Legged Robot Inertial Gain Control for Foot-Impact Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Legged robots experience instability due to spurious vibrations from foot contact with surfaces, which are amplified by control systems, leading to unnecessary corrective actions and potential instability.
Innovation Solution
A control system that reduces the gain value of an amplifier when a foot contacts a surface and gradually increases it over time based on a predetermined profile, suppressing spurious vibrations and improving control system stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the gain value of the amplifier is maintained at a nominal value during foot contact, then the control system responds quickly to all sensor inputs, but spurious vibrations are amplified causing instability and unnecessary corrective actions
Solution Approach 1:
The amplifier gain value is dynamically adjusted based on the operational state of the legged robot. During foot contact phases, the gain is reduced to a lower value to prevent vibration amplification, while during non-contact phases, the gain returns to a nominal value for responsive control. This dynamic adaptation resolves the contradiction between rapid response and stability.
Solution Approach 2:
The system changes the amplifier gain parameter according to the robot's gait cycle and foot contact state. By monitoring inertial sensor data and determining when feet are in contact with the ground, the control system adjusts the gain parameter to appropriate levels, thereby preventing spurious vibration amplification while maintaining control responsiveness when needed.
2Stability of the object's composition
If the gain value is reduced to suppress vibrations, then control system stability improves, but the responsiveness to legitimate control inputs decreases
Solution Approach 1:
The amplifier gain is periodically adjusted in synchronization with the robot's gait cycle. The control system alternates between high-gain modes (during flight phases when feet are airborne) and low-gain modes (during stance phases when feet contact the ground). This periodic modulation ensures stability during vibration-prone periods while maintaining responsiveness during stable periods.
Solution Approach 2:
The system dynamically switches amplifier gain values based on real-time detection of foot contact events. When inertial sensors detect vibrations characteristic of foot-ground contact, the gain is reduced; when such vibrations are absent, the gain returns to nominal levels. This dynamic adjustment maintains both stability and responsiveness as needed.
Data Source
AI summary
An example implementation involves receiving measurements from an inertial sensor coupled to the robot and detecting an occurrence of a foot of the legged robot making contact with a surface. The implementation also involves reducing a gain value of an amplifier from a nominal value to a reduced value upon detecting the occurrence. The amplifier receives the measurements from the inertial sensor and provides a modulated output based on the gain value. The implementation further involves increasing the gain value from the reduced value to the nominal value over a predetermined duration of time after detecting the occurrence. The gain value is increased according to a profile indicative of a manner in which to increase the gain value of the predetermined duration of time. The implementation also involves controlling at least one actuator of the legged robot based on the modulated output during the predetermined duration of time.