Spherical Robot Localization Using IMU and Wheel Odometry

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Solution Overview

Problem

Miniature robots face challenges in navigation due to high power consumption of existing localization technologies like GPS and WiFi, making it difficult for them to operate for extended periods without recharging.

Innovation Solution

A spherical robot design that uses inertial measurements and odometry data from wheel encoders to determine its location, eliminating the need for range sensors and navigation sensors, and employing a localizer to continuously update its position using a Kalman filter to minimize errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If GPS or WiFi localization technologies are used, then location accuracy is improved, but power consumption increases

Engineering Contradiction:

Improvelocation accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent replaces electronic localization systems (GPS, WiFi) with a mechanical sensing approach using inertial measurement units (IMU) and wheel encoders. The IMU measures linear acceleration and angular velocity mechanically, while encoders track wheel rotation, together providing location information without the high power consumption of wireless localization technologies.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The robot uses its own motion components (wheels and inertial sensors) to determine its location rather than relying on external infrastructure like GPS satellites or WiFi access points. The localizer integrates data from the robot's built-in sensors to calculate position, velocity, and orientation autonomously.

Inventive Principle:

Principle #25Self-service

2Adaptability or versatility

If miniature robots are designed to reduce size, then adaptability is improved, but battery capacity decreases

Engineering Contradiction:

Improveminiature sizeVSAvoidoperating time

Core Design Contradiction:

Adaptability or versatilityVSDuration of action of moving object

Solution Approach 1:

The patent replaces power-intensive electronic localization systems with mechanical sensing components (IMU and wheel encoders) that consume significantly less power. This substitution enables miniature robots to achieve adequate localization capability while maintaining small battery capacity, thereby extending operating duration.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operational parameters of localization by switching from continuous high-power wireless transmission (GPS/WiFi) to lower-power mechanical sensing and computational localization. This parameter change in power consumption enables extended operating time for miniature robots with limited battery capacity.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11216006B2Robot and method for localizing a robot

Publication Date: 2022.01.04 SINGAPORE UNIVERSITY OF TECHNOLOGY AND DESIGN

AI summary

According to various embodiments, there is provided a robot including: a spherical shell; a cart in the spherical shell, the cart including a plurality of wheels rotatable to move the cart along an inner surface of the spherical shell; a sensor coupled to the cart, the sensor configured to provide an inertial measurement of the cart; a motion encoder configured to measure an angular velocity of each wheel of the plurality of wheels; and a localizer configured to determine a location of the robot, based on the angular velocities of the plurality of wheels and the inertial measurement of the cart.