SVM Classifier for Biped Robot Fall Prediction

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Solution Overview

Problem

Current methods for monitoring the balanced state of humanoid robots are limited, as they can only perform accurately when the robot is standing stably and require extensive data collection, which is difficult and damaging to obtain, especially during falls.

Innovation Solution

A method using a support vector machine (SVM) classifier trained with state data from stable and falling robot states, incorporating angular velocity, linear acceleration, and center of mass projection distance, allowing for real-time balanced state monitoring during motion with reduced data collection and damage risk.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a machine learning method with 16 classifiers is used to predict humanoid falls, then prediction capability during motion is improved, but data collection complexity and robot damage risk increase significantly

Engineering Contradiction:
Improvefall prediction capabilityVSAvoiddata collection complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the parameter dimension by selecting 7 key state parameters (three-dimensional position and four-dimensional attitude) to form the input feature vector for the SVM classifier. This parameter selection strategy simplifies the data collection process while maintaining effective fall prediction capability during robot motion.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses support vector machine classification to create a computational model that copies and generalizes fall patterns from training data. The SVM classifier learns from labeled training samples and can predict falls in unseen situations, eliminating the need to collect extensive new data for each scenario while maintaining high prediction reliability.

Inventive Principle:
Principle #26Copying

2Measurement precision

If physical model-based methods are used to monitor balanced state, then stable standing monitoring is improved, but prediction accuracy deteriorates when contact points slide or during motion

Engineering Contradiction:
Improvebalanced state monitoring accuracyVSAvoidapplicability during motion
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent transitions from static balanced state monitoring to dynamic fall prediction by using SVM classification on time-series state data. The method processes sequential state information and can predict falls during robot motion, making the system adaptable to dynamic conditions while maintaining monitoring precision through the buffer time mechanism.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements a feedback mechanism by using the SVM classifier to continuously monitor robot state and predict potential falls. The system processes current state data, compares it against learned patterns from training, and provides prediction feedback that can trigger protective actions, enabling accurate monitoring during both stable standing and motion phases.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If extensive fall data is collected for training, then classifier accuracy is improved, but robot damage risk during data collection increases

Engineering Contradiction:
Improveclassifier accuracyVSAvoidrobot damage risk
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent treats simulation data and synthetic training samples as disposable resources that can be generated without physical risk. By using simulation environments and synthetic data generation, the system obtains sufficient training data without repeatedly subjecting the physical robot to damaging fall conditions, thus maintaining classifier accuracy while eliminating damage risk.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent converts the harmful aspect of actual falls into a benefit by using simulation and synthetic data generation techniques. Instead of collecting data through actual damaging falls, the system generates equivalent training data computationally, transforming what would be a harmful data collection process into a safe and efficient one while maintaining training effectiveness.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS11511431B2Method for monitoring balanced state of biped robot
Publication Date: 2022.11.29 BEIJING INST OF TECH
  • US11511431B2 patent drawing
  • US11511431B2 patent drawing
  • US11511431B2 patent drawing

AI summary

The present invention provides a method for monitoring a balanced state of a humanoid robot, comprising: acquiring state data of the robot falling in different directions and being stable, forming a support vector machine (SVM) training data set and obtaining, by training, an initial SVM classifier; inputting the state data of the robot to the trained SVM classifier, so that the SVM classifier outputs a classification result; taking statistics on a proportion of cycles judged to have an impending fall in the total number of control cycles within a judgment buffer time after the SVM classifier outputs the classification result, and finally determining a monitoring result of the balanced state of the robot according to the proportion and finally extracting state data of misjudged cycles within the buffer time, adding the state data to the current training data set and updating the SVM classifier, eventually enabling the classifier to achieve the effects of matching motion capabilities of the robot and monitoring the balanced state.