Gyroscope-Free Link Parameter Measurement Using Accelerometers and Magnetometer

2014 ◽  
Author(s):  
Vishesh Vikas ◽  
Carl D. Crane
Keyword(s):  
Angular Velocity ◽  
Joint Angle ◽  
Inertial Sensors ◽  
Angular Acceleration ◽  
Parameter Measurement ◽  
Joint Angles ◽  
Symmetry Constraint ◽  
Estimation Techniques ◽  
Angular Velocities ◽  
Joint Parameters

Knowledge of joint angles, angular velocities is essential for control of link mechanisms and robots. The estimation of joint angles and angular velocity is performed using combination of inertial sensors (accelerometers and gyroscopes) which are contactless and flexible at point of application. Different estimation techniques are used to fuse data from different inertial sensors. Bio-inspired sensors using symmetrically placed multiple inertial sensors are capable of instantaneously measuring joint parameters (joint angle, angular velocities and angular acceleration) without use of any estimation techniques. Calibration of inertial sensors is easier and more reliable for accelerometers as compared to gyroscopes. The research presents gyroscope-less, multiple accelerometer and magnetometer based sensors capable of measuring (not estimating) joint parameters. The contribution of the improved sensor are four-fold. Firstly, the inertial sensors are devoid of symmetry constraint unlike the previously researched bio-inspired sensors. However, the accelerometer are non-coplanarly placed. Secondly, the accelerometer-magnetometer combination sensor allows for calculation of a unique rotation matrix between two link joined by any kind of joint. Thirdly, the sensors are easier to calibrate as they consist only of accelerometers. Finally, the sensors allow for calculation of angular velocity and angular acceleration without use of gyroscopes.

Joint Angle Measurement Using Strategically Placed Accelerometers and Gyroscope

2015 ◽  
Vol 8 (2) ◽  
Author(s):  
Vishesh Vikas ◽  
Carl D. Crane
Keyword(s):  
Joint Angle ◽  
Angle Measurement ◽  
Robot Dynamics ◽  
Accelerometer Data ◽  
Joint Angles ◽  
Mems Accelerometer ◽  
Novel Approach ◽  
Angular Velocities ◽  
Measurement Units ◽  
Joint Parameters

Optical and magnetic encoders are widely used to measure joint angles. These sensors are required to be installed at the axes of rotation (joint centers). However, microelectromechanical system (MEMS) accelerometer and gyroscope-based joint angle measurement sensors possess the advantage of being flexible with regard to the point of installation. Inertial measurement units (IMUs) are capable of providing orientation and are also used for joint angle estimation. They conventionally fuse gyroscope and accelerometer data using Kalman filter-like algorithm to estimate the joint angles. This research presents a novel approach of measuring joint parameters—joint angles, angular velocities, and accelerations, of two links joined by revolute or universal joint. The gravity-invariant vestibular dynamic inclinometer (VDI) and planar VDI (pVDI) are used on each link to measure the joint parameters of links joined by revolute and universal joints, respectively. The VDI consists of two dual-axis accelerometers and an uniaxial gyroscope, while the pVDI consists of four strategically placed dual-axis accelerometers and a triaxial gyroscope. The measurements of joint parameters using the presented algorithms are independent of integration errors/drift, do not require knowledge of robot dynamics, and are computationally less burdensome.

Measurement of Robot Link Joint Parameters Using Multiple Accelerometers and Gyroscope

2013 ◽  
Author(s):  
Vishesh Vikas ◽  
Carl D. Crane
Keyword(s):  
Angular Velocity ◽  
Joint Angle ◽  
Angular Acceleration ◽  
Contact Measurement ◽  
Base Angle ◽  
Novel Approach ◽  
Contact Sensor ◽  
Joint Parameters ◽  
Integration Errors

A novel approach of dynamic, non-contact measurement of joint parameters using the planar Vestibular Dynamic Inclinometer (pVDI) is proposed in this paper. The gravity-invariant planar Vestibular Dynamic Inclinometer (pVDI) is a non-contact sensor that consists of symmetrically placed four dual-axis accelerometers and one tri-axial gyroscope. The deployment of the non-contact sensor is strategic and need not be at the joints. The paper proposes measurement of joint parameters — base angle, joint angle, angular velocity and angular acceleration, that are independent of integration errors/drift.

Joint angle variations analyses of the two link planar manipulator in welding by using inverse kinematics

Robotica ◽  
2005 ◽  
Vol 24 (3) ◽  
pp. 355-363 ◽  
Author(s):  
S. Bulut ◽  
M. B. Terzioǧlu
Keyword(s):  
Angular Velocity ◽  
Data Collection ◽  
Inverse Kinematics ◽  
Joint Angle ◽  
Joint Angles ◽  
End Effector ◽  
Fortran 90

In this paper, the joint angles of a two link planar manipulator are calculated by using inverse kinematics equations together with some geometric equalities. For a given position of the end-effector the joint angle and angular velocity of the links are derived. The analyses contains many equations which have to be solved. However, the solutions are rather cumbersome and complicated, therefore a program is written in Fortran 90 in order to do, the whole calculation and data collection. The results are given at the end of this paper.

Continuous Estimation Prediction of Knee Joint Angles Using Fusion of Electromyographic and Inertial Sensors for Active Transfemoral Leg Prostheses

2018 ◽  
Vol 10 (02) ◽  
pp. 1840008
Author(s):  
Alberto López-Delis ◽  
Cristiano J. Miosso ◽  
João L. A. Carvalho ◽  
Adson F. da Rocha ◽  
Geovany A. Borges
Keyword(s):  
Knee Joint ◽  
Joint Angle ◽  
Inertial Sensors ◽  
Sagittal Plane ◽  
Joint Angles ◽  
Knee Joint Angle ◽  
Improved Performance ◽  
Continuous Estimation ◽  
Movement Intention ◽  
Semg Signals

Information extracted from the surface electromyographic (sEMG) signals can allow for the detection of movement intention in transfemoral prostheses. The sEMG can help estimate the angle between the femur and the tibia in the sagittal plane. However, algorithms based exclusively on sEMG information can lead to inaccurate results. Data captured by inertial-sensors can improve this estimate. We propose three myoelectric algorithms that extract data from sEMG and inertial sensors using Kalman-filters. The proposed fusion-based algorithms showed improved performance compared to methods based exclusively on sEMG data, generating improvements in the accuracy of knee joint angle estimation and reducing estimation artifacts.

scholarly journals Mechanistic insights into the modulatory role of the mechanoreflex on central hemodynamics using passive leg movement in humans

2018 ◽  
Vol 125 (2) ◽  
pp. 545-552 ◽  
Author(s):  
Nicholas T. Kruse ◽  
William E. Hughes ◽  
Darren P. Casey
Keyword(s):  
Cardiac Output ◽  
Angular Velocity ◽  
Range Of Motion ◽  
Joint Angle ◽  
Feedback Mechanism ◽  
Fascicle Length ◽  
Percent Change ◽  
Muscle Fascicle ◽  
Angular Velocities ◽  
Leg Movement

The aim of this study was to examine the independent contributions of joint range of motion (ROM), muscle fascicle length (MFL), and joint angular velocity on mechanoreceptor-mediated central cardiovascular dynamics using passive leg movement (PLM) in humans. Twelve healthy men (age: 23 ± 2 yr, body mass index: 23.7 kg/m2) performed continuous PLM at various randomized joint angle ROMs (0°–50° vs. 50°–100° vs. 0°–100°) and joint angular velocities (“fast”: 200°/s vs. “slow”: 100°/s). Measures of heart rate (HR), cardiac output (CO), and mean arterial pressure (MAP) were recorded during baseline and during 60 s of PLM. MFL was calculated from muscle architectural measurements of fascicle pennation angle and tissue thickness (Doppler ultrasound). Percent change in MFL increased across the transition of PLM from 0° to 50° (15 ± 3%; P < 0.05) and from 0° to 100° knee flexion (27 ± 4%; P < 0.05). The average peak percent change in HR (increased, approx. +5 ± 2%; P < 0.05), CO (increased, approx. +5 ± 3%; P < 0.05), and MAP (decreased, approx. −2 ± 2%; P < 0.05) were similar between fast versus slow angular velocities when compared against shorter absolute joint ROMs (i.e., 0°–50° and 50°–100°). However, the condition that exhibited the greatest angular velocity in combination with ROM (0°–100° at 200°/s) elicited the greatest increases in HR (+13 ± 2%; P < 0.05) and CO (+12 ± 2%; P < 0.05) compared with all conditions. Additionally, there was a significant relationship between MFL and HR within 0°–100° at 200°/s condition ( r2 = 0.59; P < 0.05). These findings suggest that increasing MFL and joint ROM in combination with increased angular velocity via PLM are important components that activate mechanoreflex-mediated cardioacceleration and increased CO. NEW & NOTEWORTHY The mechanoreflex is an important autonomic feedback mechanism that serves to optimize skeletal muscle perfusion during exercise. The present study sought to explore the mechanistic contributions that initiate the mechanoreflex using passive leg movement (PLM). The novel findings show that progressively increasing joint angle range of motion and muscle fascicle length via PLM, in combination with increased angular velocity, are important components that activate mechanoreflex-mediated cardioacceleration and increase cardiac output in humans.

scholarly journals Preference and torque asymmetry for elbow joint

2012 ◽  
Vol 18 (2) ◽  
pp. 319-326 ◽  
Author(s):  
Felipe Pivetta Carpes ◽  
Jeam Marcel Geremia ◽  
Ana Paula Barcellos Karolczak ◽  
Fernando Diefenthaeler ◽  
Marco Aurélio Vaz
Keyword(s):  
Elbow Joint ◽  
Healthy Subjects ◽  
Joint Angle ◽  
Force Production ◽  
Functional Adaptation ◽  
Daily Activities ◽  
Elbow Flexors ◽  
Isokinetic Dynamometer ◽  
Joint Angles ◽  
Angular Velocities

Extensively unilateral recruitment for daily activities may determine performance asymmetries in favor of the preferred side eliciting functional adaptation. Our study evaluated asymmetries in elbow torque output between preferred and non-preferred limbs. Eighteen subjects performed maximal elbow flexor and extensor isometric contractions at five different elbow joint angles (0º, 30º, 60º, 90º, 120º) and five different angular velocities (60, 120, 180, 240, 300º.s-1) on an isokinetic dynamometer. Higher flexor torque in favor of preferred arm was observed at 90º of flexion (p<0.05), which also corresponded to the highest torque produced (p<0.05). The fact that joint angle influenced torque asymmetries, whereas angular velocity did not, suggest that the observed asymmetry is likely related to preferential recruitment of elbow flexors at a 90º joint angle for daily tasks requiring high levels of force production. Muscle functional adaptation to frequent stimuli at this joint angle in healthy subjects may explain these results.

Flight motion tracking with new configuration of hybrid inertial sensors

2020 ◽  
Vol 37 (5) ◽  
pp. 1683-1701
Author(s):  
Xin Wang ◽  
Jie Yan ◽  
Dongzhu Feng ◽  
Yonghua Fan ◽  
Dongsheng Yang
Keyword(s):  
Motion Tracking ◽  
Inertial Sensors ◽  
Low Cost ◽  
Angular Acceleration ◽  
Measurement Unit ◽  
Flight Vehicle ◽  
Body Frame ◽  
Content Type ◽  
Translational Movement ◽  
Angular Velocities

Purpose This paper aims to describe a novel hybrid inertial measurement unit (IMU) for motion capturing via a new configuration of strategically distributed inertial sensors, and a calibration approach for the accelerometer and gyroscope sensors mounted in a flight vehicle motion tracker built on the inertial navigation system. Design/methodology/approach The hybrid-IMU is designed with five accelerometers and one auxiliary gyroscope instead of the accelerometer and gyroscope triads in the conventional IMU. Findings Simulation studies for tracking with both attitude angles and translational movement of a flight vehicle are conducted to illustrate the effectiveness of the proposed method. Originality/value The cross-quadratic terms of angular velocity are selected to process the direct measurements of angular velocities of body frame and to avoid the integration of angular acceleration vector compared with gyro-free configuration based on only accelerometers. The inertial sensors are selected from the commercial microelectromechanical system devices to realize its low-cost applications.

Inclination Parameter Estimation for Manipulator and Humanoid Robot Links

2011 ◽  
Author(s):  
Vishesh Vikas ◽  
Carl D. Crane
Keyword(s):  
Parameter Estimation ◽  
Angular Velocity ◽  
Humanoid Robot ◽  
Angular Acceleration ◽  
Joint Angles ◽  
Contact Measurement ◽  
Base Angle ◽  
Novel Approach ◽  
Contact Sensor ◽  
Integration Errors

A novel approach of dynamic, non-contact measurement of inclination parameters for robotics applications using the Vestibular Dynamic Inclinometer (VDI) is proposed in the paper. The gravity-invariant Vestibular Dynamic Inclinometer (VDI) is a sensor that consists of symmetrically placed two dual-axis linear accelerometers and one single-axis gyroscope. The deployment of the non-contact sensor is strategic and need not be exactly at the joints. The sensor is also able to estimate the inclination parameters of the base link and the acceleration of the surface of contact. The inclination parameters — base angle, joint angles, angular velocity and angular acceleration, are independent of integration errors/drift.

scholarly journals Efficient Self-Rotation Perception

2020 ◽  
Author(s):  
Andrew Duggins
Keyword(s):  
Angular Velocity ◽  
Angular Acceleration ◽  
Rotation Velocity ◽  
Special Theory ◽  
Slow Phase ◽  
Probability Density Distribution ◽  
Theory Of Relativity ◽  
Hyperbolic Tangent ◽  
New Formalism ◽  
Angular Velocities

An event occurring within a stationary environment, in the direction toward which an observer self-rotates, is perceived to precede a simultaneous event, in the direction away from which she moves. When self-rotation results from angular acceleration in the dark, perception of space is also distorted, such that the subjective straight-ahead shifts in the opposite direction to motion and temporal event promotion. A reference frameshift theory, based on the special theory of relativity, is proposed to explain these findings. Here, a hyperbolic tangent transformation of objective angular velocity constrains subjective self-rotation velocity within finite bounds, consistent with it being a limited perceptual resource. Identifying this subjective variable with vestibular nystagmus slow-phase angular velocity, the asymptotic perceived self-rotation velocity is estimated at ~200 &deg;&frasl;s. When included in the Lorentz transformations of the new formalism, this value predicts experimental simultaneity distortion. Hypothetically, the hyperbolic tangent objective-to-subjective transfer function would maximize the differential entropy of the percept, and thereby also the stimulus/percept mutual information, if angular velocities of body rotation encountered in naturalistic environmental interaction have a logistic probability density distribution of scale 100 &deg;&frasl;s, a proposed experimental test of the scheme.

scholarly journals Determining Subject-Specific Torque Parameters for Use in a Torque-Driven Simulation Model of Dynamic Jumping

2002 ◽  
Vol 18 (3) ◽  
pp. 207-217 ◽  
Author(s):  
Mark A. King ◽  
Maurice R. Yeadon
Keyword(s):  
Angular Velocity ◽  
Knee Joint ◽  
Knee Extension ◽  
Joint Torque ◽  
Joint Angles ◽  
Maximum Torque ◽  
Torque Measurements ◽  
Subject Specific ◽  
Angular Velocities ◽  
Torque Angle

This paper describes a method for defining the maximum torque that can be produced at a joint from isovelocity torque measurements on an individual. The method is applied to an elite male gymnast in order to calculate subject-specific joint torque parameters for the knee joint. Isovelocity knee extension torque data were collected for the gymnast using a two-repetition concentric-eccentric protocol over a 75° range of crank motion at preset crank angular velocities ranging from 20 to 250°s–1. During these isovelocity movements, differences of up to 35° were found between the angle of the dynamometer crank and the knee joint angle of the participant. In addition, faster preset crank angular velocities gave smaller ranges of isovelocity motion for both the crank and joint. The simulation of an isovelocity movement at a joint angular velocity of 150°s–1 showed that, for realistic series elastic component extensions, the angular velocity of the joint can be assumed to be the same as the angular velocity of the contractile component during most of the isovelocity trial. Fitting an 18-parameter exponential function to experimental isovelocity joint torque/ angle/ angular velocity data resulted in a surface that was well behaved over the complete range of angular velocities and within the specified range of joint angles used to calculate the surface.

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