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.

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.

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.

Kinematics of rotation in place during defense turning in the crayfish Procambarus clarkii

2001 ◽  
Vol 204 (3) ◽  
pp. 471-486 ◽  
Author(s):  
N. Copp ◽  
M. Jamon
Keyword(s):  
Angular Velocity ◽  
Procambarus Clarkii ◽  
Angular Acceleration ◽  
The Body ◽  
Simple Variation ◽  
Freely Behaving ◽  
Leg Motion ◽  
Two Phases ◽  
Analysis System ◽  
Final Orientation

The kinematic patterns of defense turning behavior in freely behaving specimens of the crayfish Procambarus clarkii were investigated with the aid of a video-analysis system. Movements of the body and all pereiopods, except the chelipeds, were analyzed. Because this behavior approximates to a rotation in place, this analysis extends previous studies on straight and curve walking in crustaceans. Specimens of P. clarkii responded to a tactile stimulus on a walking leg by turning accurately to face the source of the stimulation. Angular velocity profiles of the movement of the animal's carapace suggest that defense turn responses are executed in two phases: an initial stereotyped phase, in which the body twists on its legs and undergoes a rapid angular acceleration, followed by a more erratic phase of generally decreasing angular velocity that leads to the final orientation. Comparisons of contralateral members of each pair of legs reveal that defense turns are affected by changes in step geometry, rather than by changes in the timing parameters of leg motion, although inner legs 3 and 4 tend to take more steps than their outer counterparts during the course of a response. During the initial phase, outer legs 3 and 4 exhibit larger stance amplitudes than their inner partners, and all the outer legs produce larger stance amplitudes than their inner counterparts during the second stage of the response. Also, the net vectors of the initial stances, particularly, are angled with respect to the body, with the power strokes of the inner legs produced during promotion and those of the outer legs produced during remotion. Unlike straight and curve walking in the crayfish, there is no discernible pattern of contralateral leg coordination during defense turns. Similarities and differences between defense turns and curve walking are discussed. It is apparent that rotation in place, as in defense turns, is not a simple variation on straight or curve walking but a distinct locomotor pattern.

Mathematical Models of Control Systems of Angular Speed of Steam Turbines for Diagnostic Tests of Automatic and Mechatronic Devices

2013 ◽  
Vol 198 ◽  
pp. 519-524
Author(s):  
Grzegorz Redlarski ◽  
Janusz Piechocki ◽  
Mariusz Dąbkowski
Keyword(s):  
Angular Velocity ◽  
Power System ◽  
Control Systems ◽  
Working Conditions ◽  
Diagnostic Tests ◽  
Angular Acceleration ◽  
Angular Speed ◽  
Physical Parameters ◽  
Steam Turbines ◽  
Parallel Operation

In many automatics and mechatronics systems accurate modeling of several physical processes is needed. In power system, one of these is the process of control of angular velocity of power blocks during their connection to parallel operation. This process is extremely dynamic and the response of control system results from continuous changes in many physical parameters (temperature, pressure and flow of the working medium, etc.). An accuracy of modeling this process influences int. al. on: quality of the automatic synchronizer diagnostic tests in the laboratory, as well as the possibility of evaluation of prospects for connection process in the power system, without the automatic synchronizer [. Automatics systems used for research and diagnosis of automatic synchronizers are known in the literature as and simulators [2, . To impose similar to real working conditions, it is required to implement an appropriate models of control systems. One of such models, representative for the larger population of objects, is model of control systems of angular velocity. Currently used models, e.g. [3, 4, 5, , allow to approximate the response of real object, or to impose higher restricted conditions of work, for example: related to the angular acceleration dω/dt, the size of overshoots and decay time of transitional characteristics, while accurate modeling the real working conditions using them is not possible. Furthermore, their use requires knowledge of the (often difficult to access) object parameters and time-consuming selection of manual procedure of certain substitute settings, occurring in these models. To eliminate inconveniences mentioned above, in the paper the proposal and mathematical modeling procedure is presented, which allow to obtain much more accurate transitional characteristics of real objects.

Research on the Kinematic Characteristics of Digging Tree Mechanism of Tree Transplanter

2014 ◽  
Vol 620 ◽  
pp. 381-387 ◽  
Author(s):  
De Jin Zhao ◽  
Yan Ling Guo ◽  
Wen Long Song
Keyword(s):  
Angular Velocity ◽  
Dynamic Simulation ◽  
Analytical Method ◽  
Angular Acceleration ◽  
Hydraulic Cylinder ◽  
Matlab Software ◽  
Kinematic Characteristics ◽  
Adams Software ◽  
Model File

In order to study the kinematic characteristics of the tree transplanter and the hydraulic cylinder, this paper established the model of the tree transplanter with the Cero2.0 software and analyzed kinematic characteristics of the hydraulic cylinder and the tree spade when the tree spade was driven by the hydraulic cylinder with the analytical method. The dynamic simulation curves of the angular velocity and the angular acceleration of the hydraulic cylinder can be obtained with the Matlab software. Then the appropriate format model file was imported into Adams software, and the angular velocity and the angular acceleration of the hydraulic cylinder were analyzed and simulated in Adams. The obtained curves in Adams software were compared with the curves obtained with the Matlab using the analytical method. The result revealed that the trends of the two ways simulation curves were consistent. The comparison showed the analytical method of kinematic characteristics of the tree transplanter and hydraulic cylinder was correct.

scholarly journals A Novel Method for Estimating Knee Angle Using Two Leg-Mounted Gyroscopes for Continuous Monitoring with Mobile Health Devices

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2759 ◽  
Author(s):  
Eric Allseits ◽  
Kyoung Kim ◽  
Christopher Bennett ◽  
Robert Gailey ◽  
Ignacio Gaunaurd ◽  
...  
Keyword(s):  
Angular Velocity ◽  
Knee Joint ◽  
Convergent Validity ◽  
Continuous Monitoring ◽  
Joint Angle ◽  
Characteristic Point ◽  
Accelerometer Data ◽  
Knee Angle ◽  
Velocity Signal ◽  
Knee Joint Angle

Tele-rehabilitation of patients with gait abnormalities could benefit from continuous monitoring of knee joint angle in the home and community. Continuous monitoring with mobile devices can be restricted by the number of body-worn sensors, signal bandwidth, and the complexity of operating algorithms. Therefore, this paper proposes a novel algorithm for estimating knee joint angle using lower limb angular velocity, obtained with only two leg-mounted gyroscopes. This gyroscope only (GO) algorithm calculates knee angle by integrating gyroscope-derived knee angular velocity signal, and thus avoids reliance on noisy accelerometer data. To eliminate drift in gyroscope data, a zero-angle update derived from a characteristic point in the knee angular velocity is applied to every stride. The concurrent validity and construct convergent validity of the GO algorithm was determined with two existing IMU-based algorithms, complementary and Kalman filters, and an optical motion capture system, respectively. Bland–Altman analysis indicated a high-level of agreement between the GO algorithm and other measures of knee angle.

Kinematic Analysis of Mechanisms by the Complex Conjugate Exponential Method

1975 ◽  
Vol 97 (3) ◽  
pp. 795-799 ◽  
Author(s):  
J. A. Smith
Keyword(s):  
Angular Velocity ◽  
Closed Form ◽  
Kinematic Analysis ◽  
Angular Position ◽  
Angular Acceleration ◽  
Dynamic State ◽  
Complex Conjugate ◽  
Iterative Techniques ◽  
Numerical Example ◽  
Exponential Method

Generalized closed-form expressions are presented for the analysis of angular and path position and dynamic state properties of an n link mechanism with single or multiple prescribed input specifications. The complex conjugate concept is extensively used to formulate these explicit expressions. A numerical example of a six-bar mechanism is presented, and the closed-form expressions are used to calculate—without graphical, numerical, or iterative techniques—the angular position, angular velocity, and angular acceleration of each link.

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