Real-Time Estimation of Glenohumeral Joint Rotation Center With CAREX: A Cable-Based Arm Exoskeleton

2012 ◽  
Author(s):  
Ying Mao ◽  
Xin Jin ◽  
Sunil K. Agrawal
Keyword(s):  
Real Time ◽  
Healthy Subjects ◽  
Degrees Of Freedom ◽  
Glenohumeral Joint ◽  
Kinematic Model ◽  
Time Estimation ◽  
Estimation Algorithm ◽  
Experimental Results ◽  
Joint Rotation ◽  
Rotation Center

In the past few years, the authors have proposed several prototypes of a Cable-driven upper ARm EXoskeleton (CAREX) for arm rehabilitation. The key advantages of CAREX over conventional exoskeletons are: (i) It is nearly an order of magnitude lighter. (ii) It does not have conventional links and joints, hence does not require joint axes alignment and segment lengths adjustment. (iii) It does not limit the natural degrees-of-freedom of the upper limb. (iv) The structure of the exoskeleton is novel as the cables are routed from the proximal to the distal segments of the arm. Preliminary experimental results with CAREX on a robotic arm and on healthy subjects have demonstrated the effectiveness of the exoskeleton within “assist-as-needed” training paradigm. In this paper, we propose a novel approach to estimate the glenohumeral joint rotation center (GH-c) using measurements of shoulder joint angles and cable lengths. This helps in locating the glenohumeral joint rotation center appropriately within the kinematic model. As a result, more accurate kinematic model can be used to improve the training of human users. An estimation algorithm is presented to compute the GH-c in real-time. The algorithm was implemented on the latest prototype of CAREX which controls four degrees-of-freedom of the shoulder and elbow. Preliminary experiments were performed on two healthy subjects under two different scenarios: (i) GH-c was assumed to be a fixed point and (ii) GH-c was estimated using the proposed algorithm. Experimental results are presented to compare the two scenarios.

scholarly journals Real-Time Estimation of Glenohumeral Joint Rotation Center With Cable-Driven Arm Exoskeleton (CAREX)—A Cable-Based Arm Exoskeleton

2013 ◽  
Vol 6 (1) ◽  
Author(s):  
Ying Mao ◽  
Xin Jin ◽  
Sunil K. Agrawal
Keyword(s):  
Real Time ◽  
Glenohumeral Joint ◽  
Kinematic Model ◽  
Estimation Method ◽  
Time Estimation ◽  
Estimation Algorithm ◽  
Joint Rotation ◽  
Rotation Center ◽  
Arm Rehabilitation ◽  
Novel Approach

In the past few years, the authors have proposed several prototypes of a Cable-driven upper ARm EXoskeleton (CAREX) for arm rehabilitation. One of the assumptions of CAREX was that the glenohumeral joint rotation center (GH-c) remains stationary in the inertial frame during motion, which leads to inaccuracy in the kinematic model and may hamper training performance. In this paper, we propose a novel approach to estimate GH-c using measurements of shoulder joint angles and cable lengths. This helps in locating the GH-c center appropriately within the kinematic model. As a result, more accurate kinematic model can be used to improve the training of human users. An estimation algorithm is presented to compute the GH-c in real-time. The algorithm was implemented on the latest prototype of CAREX. Simulations and preliminary experimental results are presented to validate the proposed GH-c estimation method.

Heading Estimation Based on Magnetic Markers for Intelligent Vehicles

2016 ◽  
Vol 138 (7) ◽  
Author(s):  
Yeun Sub Byun ◽  
Young Chol Kim
Keyword(s):  
Real Time ◽  
Autonomous Vehicle ◽  
Kinematic Model ◽  
Estimation Method ◽  
Intelligent Vehicles ◽  
Experimental Results ◽  
Main Concept ◽  
Heading Angle ◽  
Magnetic Markers ◽  
Heading Estimation

This paper presents a new real-time heading estimation method for an all-wheel steered single-articulated autonomous vehicle guided by a magnetic marker system. To achieve good guidance control for the vehicle, precise estimation of the position and heading angle during travel is necessary. The main concept of this study is to estimate the heading angle from the relative orientations of the magnetic markers and the vehicle motion. To achieve this, a kinematic model of the all-wheel steered vehicle is derived and combined with the motion of a magnetic ruler mounted near each axle underneath the vehicle. The position coordinates and polarities of the magnetic markers, which are provided a priori, are used to determine the vehicle position at every detection instance. A gyroscope is employed to assist real-time heading estimation at sample times when there are no marker detection data. The proposed method was tested on a real vehicle and evaluated by comparing the experimental results with those of the differential global positioning system (DGPS) in real-time kinematics (RTK) mode. Experimental results show that the proposed method exhibits good performance for heading estimation.

scholarly journals Movement Onset Detection and Target Estimation for Robot-Aided Arm Training

2015 ◽  
Vol 63 (4) ◽  
Author(s):  
Robert Riener ◽  
Domen Novak
Keyword(s):  
Eye Tracking ◽  
Real Time ◽  
Time Use ◽  
Healthy Subjects ◽  
Robot Control ◽  
Contextual Information ◽  
Estimation Algorithm ◽  
Movement Onset ◽  
Joint Torques ◽  
Arm Rehabilitation

AbstractThis paper presents a motion intention estimation algorithm that is based on the recordings of joint torques, joint positions, electromyography, eye tracking and contextual information. It is intended to be used to support a virtual-reality-based robotic arm rehabilitation training. The algorithm first detects the onset of a reaching motion using joint torques and electromyography. It then predicts the motion target using a combination of eye tracking and context, and activates robotic assistance toward the target. The algorithm was first validated offline with 12 healthy subjects, then in a real-time robot control setting with 3 healthy subjects. In offline crossvalidation, onset was detected using torques and electromyography 116 ms prior to detectable changes in joint positions. Furthermore, it was possible to successfully predict a majority of motion targets, with the accuracy increasing over the course of the motion. Results were slightly worse in online validation, but nonetheless show great potential for real-time use with stroke patients.

A Method for Real-Time Estimating Pose of Large Aircraft Component in Process of Pose Adjustment Based on the Unscented Kalman Filter

2012 ◽  
Vol 442 ◽  
pp. 251-255
Author(s):  
Zheng Ying
Keyword(s):  
Kalman Filter ◽  
Real Time ◽  
Unscented Kalman Filter ◽  
Kinematic Model ◽  
Estimation Method ◽  
Time Estimation ◽  
Measuring Point ◽  
Aircraft Component ◽  
Forward Kinematic ◽  
Large Aircraft

To estimate the pose of large aircraft component in pose adjustment quickly and accurately, a real-time estimation method based on Unscented Kalman filter (UKF) is proposed. Firstly, in the process of the aircraft component adjustment, a rough value of aircraft component’s pose is acquired by using forward kinematic model and the displacement of positioners on real time. Then, position of a measuring point fixed on aircraft component is obtained by a laser tracker. At last, UKF is employed to integrate the previous rough value and the measuring point position for evaluating the accurate pose of aircraft component. Numerical simulation results show that the presented method is achieved easily, calculated fast and high accurate.

BATMAV: Development and Testing of a SMA-Based Bio-Inspired Flapping Platform

2010 ◽  
Author(s):  
Gheorghe Bunget ◽  
Stefan Seelecke
Keyword(s):  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Biologically Inspired ◽  
Joint Rotation ◽  
Systematic Analysis ◽  
Trailing Edges ◽  
Aerial Vehicle ◽  
Kinematic Models ◽  
Bat Wing ◽  
Thrust Forces

The overall objective of the BATMAV project is the development of a biologically-inspired Micro Aerial Vehicle (MAV) with flexible and foldable wings for flapping flight. This paper presents a platform that features bat-inspired wings which are able to mimic the folding motion of the elbow and wrist joints of the natural flyer. This flapping platform makes use of the dual roll of the Shape Memory Alloys (SMA) to mimic the flexible joints and flapping muscles of the natural wings. The approach of this project was to learn from the natural flyer through a systematic analysis of their flight and to mimic their flapping mechanisms. A systematic study of the bat flight kinematics helped to identify the required joint angles as relevant degrees of freedom for wing actuation. Kinematic models of wings with 2 and 3-DOFs have been developed with the intention of mimicking the wing trajectories of the natural flier Plecotus auritus. A further kinematic model for the joint rotation angle has been developed in order to determine the attachment locations of SMA ‘muscle-wires’ as well as their routes along the wing ‘bones’. As part of this study individual elbow-joint systems were designed, fabricated and used to experimentally validate the above model’s prediction. The elastic skin membrane of the bat wing has been reproduced using a thin-film silicon membrane which has been suitably prestrained and shaped to mimic the leading and trailing edges of the bat wing. To measure the aerodynamic forces developed by the flapping platform, a test stand consisting of two load cells was assembled, and the dynamic tests were performed for a 2-DOF flapping wings. The lift and thrust forces as well as the flapping amplitude were measured.

scholarly journals Research on Torque Distribution of Four-Wheel Independent Drive Off-Road Vehicle Based on PRLS Road Slope Estimation

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Hongwei Ling ◽  
Bin Huang
Keyword(s):  
Real Time ◽  
Control Strategy ◽  
Time Estimation ◽  
Estimation Algorithm ◽  
Torque Distribution ◽  
Precise Control ◽  
The Road ◽  
Time Simulation ◽  
Road Gradient ◽  
Driving Torque

In view of the high difficulty in coupling of various electric vehicle parameters, intractable parameter estimation, and unreasonable distribution of vehicle driving torque, the four-wheel hub motor is applied to drive electric vehicles, which can instantly obtain the torque and speed of the hub motor and achieve precise control of the torque of each wheel. According to the vehicle longitudinal dynamics model, a progressive RLS (PRLS) algorithm for real-time estimation of vehicle mass and road gradient is proposed. Meanwhile, by means of taking the longitudinal acceleration of the vehicle and the road gradient obtained from the estimation algorithm as the parameter of the torque distribution at the front and rear axles, a dynamic compensation and distribution control strategy of the front and rear axle torques is designed. Moreover, based on hardware-in-the-loop real-time simulation and real-vehicle tests, the effectiveness of the proposed estimation algorithm and the rationality of the real-time distribution control strategy of driving torque are verified.

scholarly journals Comparison of Two Methods for In Vivo Estimation of the Glenohumeral Joint Rotation Center (GH-JRC) of the Patients with Shoulder Hemiarthroplasty

PLoS ONE ◽  
2011 ◽  
Vol 6 (3) ◽  
pp. e18488 ◽  
Author(s):  
Ali Asadi Nikooyan ◽  
Frans C. T. van der Helm ◽  
Peter Westerhoff ◽  
Friedmar Graichen ◽  
Georg Bergmann ◽  
...  
Keyword(s):  
Glenohumeral Joint ◽  
Joint Rotation ◽  
Shoulder Hemiarthroplasty ◽  
Rotation Center
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