Suspended-Load Backpack Impedance Suspension for Vibration Filtering
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Solution Overview
Problem
Existing suspended-load backpacks with flexible and low damping suspensions are ineffective beyond a narrow range of payload and walking speed, failing to effectively reduce metabolic costs and prevent musculoskeletal injuries due to excessive displacements under high loads.
Innovation Solution
A suspended-load backpack with an adjustable impedance suspension system incorporating an inerter and adjustable stiffness module, which filters movements by altering the natural frequency and stiffness of the system, using an inerter to increase inertia and an adjustable stiffness module to adjust the spring constant, thereby damping and filtering movements relative to the ground.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a flexible and low damping suspension is used, then the user's energy efficiency while walking is improved, but the suspension is subject to excessive displacements under high loads, limiting effectiveness to a narrow range of payload and walking speed
Solution Approach 1:
The suspension system uses a variable stiffness mechanism that dynamically adjusts the stiffness of the suspension element based on the payload weight. The mechanism includes a movable pivot point that changes the effective length and stiffness of the suspension element as the load varies, allowing the system to optimize between energy efficiency and displacement control across different operating conditions
Solution Approach 2:
The invention changes the stiffness parameter of the suspension system adaptively. By using a variable stiffness mechanism with a movable pivot and adjustment element, the system modifies the suspension's mechanical properties in real-time based on the carried load, transitioning from a fixed-parameter system to one that optimizes performance across a wide range of payloads and walking speeds
2Force
If a low stiffness suspension is used, then the movement of the loading chamber relative to the ground is reduced, but the suspension becomes subject to excessive displacements under high loads
Solution Approach 1:
The suspension system dynamically adjusts its stiffness characteristic based on the payload. The variable stiffness mechanism allows the suspension to provide appropriate stiffness levels differentially - softer for light loads to minimize displacement, and stiffer for heavy loads to control reaction forces, thereby resolving the contradiction between force reduction and displacement control
3Adaptability or versatility
If a fixed stiffness suspension is used, then the system is simple, but it cannot effectively operate across a wide range of payloads and walking speeds
Solution Approach 1:
The invention implements a dynamic stiffness adjustment mechanism that allows the suspension to adapt to varying payloads and walking speeds. The variable stiffness mechanism, while adding some complexity, enables the system to maintain optimal performance across a wide operating range, justifying the increased complexity through significantly improved versatility and adaptability
Solution Approach 2:
The suspension system incorporates a mechanism that changes the stiffness parameter in response to varying operating conditions. This allows the system to optimize its mechanical characteristics for different payloads and walking speeds, transforming a fixed-parameter system into an adaptive one that maintains effectiveness across diverse operating scenarios
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 system effectively reduces metabolic costs and minimizes musculoskeletal stress across various payloads and walking speeds by damping and filtering movements, enhancing user comfort and safety.
Implementation Method 1
an inerter which is connected in parallel with the adjustable stiffness module and which increases the effective inertia
Implementation Method 2
the adjustable stiffness module adjusts the natural frequency by changing the spring constant of the system
Implementation Method 3
the suspension system filters the movements of the loading chamber by changing the natural frequency of the system
Data Source
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AI summary
The present invention relates to a suspended-load backpack (10) comprising a loading chamber (20) suitable for placing therein the loads to be carried; at least one strap (30); an adjustable impedance suspension system (40) having a first connection portion (41) where it is connected with the strap (30) and a second connection portion (42) where it is connected with the loading chamber (20) and enabling that the movements of the loading chamber (20) perpendicular to the ground caused by the movement of the user, when in use, are filtered; an adjustable stiffness module (50) located on the suspension system (40), one end of which is connected with the first connection portion (41) and the other end of which is connected with the second connection portion (42).