Knee-Mounted Biomechanical Power Generator

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Solution Overview

Problem

Existing biomechanical energy harvesting devices face challenges in efficiently generating electrical power from human or animal movement while minimizing metabolic energy expenditure and maintaining user comfort, as they often require substantial loads, disrupt gait patterns, and add mass to the user's limbs.

Innovation Solution

A biomechanical electrical generation apparatus that captures motion from a pair of limbs, integrates this motion to produce rotational energy, and uses a generator to produce electrical power, with a controller adjusting the electrical load based on limb motion to optimize power generation without hindering user movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If inertia-based systems use a suspended-load backpack to capture up-and-down movement during walking, then electrical power generation is improved, but the user must carry a substantial load and the oscillating mass disrupts gait pattern and walking stability

Engineering Contradiction:

Improveelectrical power generationVSAvoidload carried by user

Core Design Contradiction:

PowerVSWeight of moving object

Solution Approach 1:

The system divides the power generation function into two separate knee-mounted harvesters (one on each leg) rather than using a single centralized suspended load, allowing distributed energy capture that doesn't require carrying substantial weight on the back

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent replaces the mechanical suspended-load system with brushless DC rotary magnetic generators that convert knee joint motion directly into electrical energy, eliminating the need for heavy suspended masses and improving power generation efficiency

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If impact-force-based systems harvest energy from heel impact during walking, then energy capture from normal gait is improved, but the electrical power generated remains small

Engineering Contradiction:

Improveenergy harvesting during normal walkingVSAvoidelectrical power output

Core Design Contradiction:

Ease of operationVSPower

Solution Approach 1:

The system skips the heel impact stage and directly captures energy from the larger knee joint motion during the swing phase of gait, where significantly more mechanical energy is available for conversion to electrical power

Inventive Principle:

Principle #21Skipping (Rushing through)

Solution Approach 2:

The patent changes the capture point from high-frequency low-energy heel impacts to lower-frequency high-energy knee joint movements, optimizing the balance between ease of operation during normal gait and electrical power output

Inventive Principle:

Principle #35Parameter changes

3Power

If motion-based systems mount a generator on the knee to harvest energy from leg deceleration, then electrical power generation is improved, but the added mass distally increases metabolic energy expenditure by 20%

Engineering Contradiction:

Improveelectrical power generationVSAvoidmetabolic energy expenditure

Core Design Contradiction:

PowerVSUse of energy by moving object

Solution Approach 1:

The system uses regenerative braking control that dynamically switches power generation on/off based on gait phase detection, activating only during the swing phase when knee deceleration occurs, thereby minimizing metabolic cost while maintaining effective power generation

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent incorporates sensors and control systems that monitor gait phase and knee joint motion in real-time, providing feedback to optimize the timing and magnitude of power generation, ensuring energy is harvested only when natural deceleration occurs without increasing metabolic expenditure

Inventive Principle:

Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The apparatus effectively generates significant electrical power with reduced metabolic cost and minimal disruption to the user's gait, achieving higher power output than previous designs while minimizing weight and discomfort.

Implementation Method 1

an electrical generator mechanically coupled to the output motion of the motion integrator; wherein the electrical generator generates electrical power from the output motion of the motion integrator

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS9407125B2Biomechanical electrical power generation apparatus

Publication Date: 2016.08.02 LI QINGGUO

AI summary

An apparatus and method for generating electrical power from a user comprises a motion capture apparatus that captures at least a portion of motion of a pair of limbs of the user; a motion integrator mechanically coupled to the motion capture apparatus such that captured motion of the pair of limbs is transferred to the motion integrator, and the motion integrator produces an output motion; an adaptive controller, and an electrical generator mechanically coupled to the output motion of the motion integrator; wherein the electrical generator generates electrical power from the output motion of the motion integrator. The apparatus may be adapted to be carried on the user's back. In one embodiment the apparatus is incorporated into a backpack.