Related Experiment Video
Updated: Oct 17, 2025
06:52
An Inertial Measurement Unit Based Method to Estimate Hip and Knee Joint Kinematics in Team Sport Athletes on the Field
Published on: May 26, 2020
8.2K
Development of a Low-Cost Open-Source Measurement System for Joint Angle Estimation.
Túlio Fernandes de Almeida1, Edgard Morya1, Abner Cardoso Rodrigues1
1Graduate Program in Neuroengineering, Edmond and Lily Safra International Institute of Neuroscience, Santos Dumont Institute, Macaíba 59280-000, Brazil.
Sensors (Basel, Switzerland)
|October 13, 2021
Summary
This study presents a low-cost, open-source system using inertial measurement units (IMUs) for joint angle estimation. The system demonstrates accurate joint angle measurement in laboratory and real-world scenarios, offering a viable alternative for motion analysis.
Area of Science:
- Biomechanics
- Wearable Technology
- Robotics
Background:
- Inertial Measurement Units (IMUs) offer a cost-effective method for measuring joint angles.
- Existing systems for joint angle estimation can be expensive and complex.
- Open-source solutions are needed to increase accessibility in research and clinical applications.
Purpose of the Study:
- To develop and validate a low-cost, open-source measurement system for joint angle estimation using IMUs.
- To assess the system's performance in controlled and real-world environments.
- To compare the system's software accuracy against gold-standard devices.
Main Methods:
- Hardware development using low-cost IMUs and microcontrollers.
- Software development in Python, incorporating Complementary, Kalman, and Madgwick fusion filters.
- Experimental validation involving a Lokomat robotic knee, a healthy adult during gait, and comparison with ground truth data.
Main Results:
- The system achieved an average range of motion (ROM) of 58.28° for the Lokomat knee.
- In a real-world gait scenario, the system recorded an average knee ROM of 44.62°.
- Software comparison with ground truth yielded a root-mean-square error of 0.04 and a mean average percentage error of 2.95%.
Conclusions:
- The developed low-cost, open-source IMU system provides accurate joint angle estimation.
- The system's modular hardware and versatile software filters demonstrate effectiveness in diverse scenarios.
- These findings support the system's potential application in various motion analysis contexts.
Related Concept Videos
01:30Electronic Distance Measuring Instruments
162
Electronic Distance Measuring Instruments (EDMs) are essential tools in modern surveying, offering precise distance measurements by emitting electromagnetic signals and calculating the time required for these signals to travel to a target and return. Two primary types of signals are used in EDMs — light waves and microwaves — each suited to specific environmental and distance requirements. Light-wave-based EDMs utilize either infrared or laser light, providing high accuracy over...
162
01:24One-Degree-of-Freedom System
574
In mechanical engineering, one-degree-of-freedom systems form the basis of a wide range of electrical and mechanical components. Using these models, engineers can predict the behavior of various parts in a larger system, which gives them insight into how different forces interact with each other.
A one-degree-of-freedom system is defined by an independent variable that determines its state and behavior. One example of a one-degree-of-freedom system is a simple harmonic oscillator, such as a...
A one-degree-of-freedom system is defined by an independent variable that determines its state and behavior. One example of a one-degree-of-freedom system is a simple harmonic oscillator, such as a...
574
01:18Distance Measurements by Taping
155
Tapes are essential in surveying for accurate, durable, and short-distance measurements. Made from lightweight, nylon-coated steel, they offer flexibility and strength for rugged outdoor use. The nylon coating protects against rust and wear, extending the tape's life. Standard lengths, around 30 meters, are marked in meters and millimeters for precision.Surveyors select tapes based on site conditions and accuracy needs. Lightweight, nylon-coated tapes are commonly used for ease of handling and...
155
01:07Development of the Limb Synovial Joints
1.8K
Joints form during embryonic development in conjunction with the formation and growth of the associated bones. The embryonic tissue that gives rise to all bones, cartilage, and connective tissues of the body is called mesenchyme.
The mesenchymal stem cells differentiate into chondrocytes that form the hyaline cartilage, and later the cartilaginous model of the bone. This model further transforms into a bone. This process is known as endochondral ossification.
During development, the limbs...
The mesenchymal stem cells differentiate into chondrocytes that form the hyaline cartilage, and later the cartilaginous model of the bone. This model further transforms into a bone. This process is known as endochondral ossification.
During development, the limbs...
1.8K
01:17Measurement of Blood Pressure
1.8K
Assessing blood pressure is a standard procedure executed in virtually all medical environments. The method utilized today was established over a hundred years ago by an innovative Russian doctor, Dr. Nikolai Korotkoff. The soft ticking noise, known as Korotkoff sounds, heard while taking blood pressure readings results from turbulent blood flow within the vessels. The apparatus required for this procedure includes a sphygmomanometer, a blood pressure cuff attached to a gauge, and a...
1.8K
01:27Measurements of Strain
2.3K
Strain quantifies the deformation of a material under force, typically measured as normal strain, which represents the change in length when compared with the original length. Electrical strain gauges are used for enhanced accuracy. These devices consist of a conductive wire mounted on a paper backing that adheres to the material's surface. These gauges operate on the piezoresistive effect, where the wire's electrical resistance changes in response to mechanical deformation. The strain...
2.3K