Reach Posture Prediction of Upper Limb for Ergonomic Workspace Evaluation

1992 ◽  
Vol 36 (10) ◽  
pp. 702-706 ◽  
Author(s):  
Eui S. Jung ◽  
Dohyung Kee ◽  
Min K. Chung
Keyword(s):  
Upper Limb ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Local Optimality ◽  
Redundant Manipulator ◽  
Performance Function ◽  
Posture Prediction ◽  
The Subject ◽  
Analysis System ◽  
Joint Range

Proper assessment of reach posture is one of the essential functions for ergonomic workspace evaluation in CAD systems with a built-in man-model. In this study, Each upper limb is modelled as a four-link system, consisting of trunk, upper arm, lower arm, and hand, being regarded as a redundant manipulator with a total of eight degrees of freedom. Inverse kinematics is introduced in this study to predict the trajectory of multi-link segmental movement. Among several kinematic methods for solving the multi-link system, the resolved motion method was found to be effective to solve this redundant manipulator model, and the joint range availability was used as a performance function in order to guarantee local optimality. Real reach postures taken from the subject were analyzed by Motion Analysis System and showed reasonable results when compared to those obtained from the model.

Design and Implementation of a Binary Redundant Manipulator With Cascaded Modules1

2015 ◽  
Vol 8 (1) ◽  
Author(s):  
Emmanouil Tzorakoleftherakis ◽  
Anastasia Mavrommati ◽  
Anthony Tzes
Keyword(s):  
Computational Complexity ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Redundant Manipulator ◽  
Stable States ◽  
Design And Implementation ◽  
Serial Robot ◽  
The Subject ◽  
Forward And Inverse Kinematics ◽  
Three Degrees Of Freedom

The subject of this paper is the design and implementation of a prototype snakelike redundant manipulator. The manipulator consists of cascaded modules eventually forming a macroscopically serial robot and is powered by shape memory alloy (SMA) wires. The SMAs (NiTi) act as binary actuators with two stable states and as a result, the repeatability of the manipulator's movement is ensured, alleviating the need for complex feedback sensing. Each module is composed of a customized spring and three SMA wires which form a tripod with three degrees of freedom (DOFs). Embedded microcontrollers networked with the I2C protocol activate the actuators of each module individually. In addition, we discuss certain design aspects and propose a solution that deals with the limited absolute stroke achieved by SMA wires. The forward and inverse kinematics of the binary manipulator are also presented and the tradeoff between maneuverability and computational complexity is specifically addressed. Finally, the functionality and maneuverability of this design are verified in simulation and experimentally.

Posture Prediction Versus Inverse Kinematics

2001 ◽  
Author(s):  
Karim Abdel-Malek ◽  
Wei Yu ◽  
Zan Mi ◽  
E. Tanbour ◽  
M. Jaber
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Human Performance ◽  
Inverse Kinematic ◽  
Cost Functions ◽  
Optimization Approach ◽  
Final Position ◽  
Serial Robot ◽  
Posture Prediction

Abstract Inverse kinematics is concerned with the determination of joint variables of a manipulator given its final position or final position and orientation. Posture prediction also refers to the same problem but is typically associated with models of the human limbs, in particular for postures assumed by the torso and upper extremities. There has been numerous works pertaining to the determination and enumeration of inverse kinematic solutions for serial robot manipulators. Part of these works have also been directly extended to the determination of postures for humans, but have rarely addressed the choice of solutions undertaken by humans, but have focused on purely kinematic solutions. In this paper, we present a theoretical framework that is based on cost functions as human performance measures, subsequently predicting postures based on optimizing one or more of such cost functions. This paper seeks to answer two questions: (1) Is a given point reachable (2) If the point is reachable, we shall predict a realistic posture. We believe that the human brain assumes different postures driven by the task to be executed and not only on geometry. Furthermore, because of our optimization approach to the inverse kinematics problem, models with large number of degrees of freedom are addressed. The method is illustrated using several examples.

scholarly journals Active Upper Limb Prosthesis Based on Natural Movement Trajectories

2010 ◽  
Vol 34 (1) ◽  
pp. 58-72 ◽  
Author(s):  
Alfredo Ramírez-García ◽  
Lorenzo Leija ◽  
Roberto Muñoz
Keyword(s):  
Upper Limb ◽  
Degrees Of Freedom ◽  
Elbow Flexion ◽  
Motion Patterns ◽  
Movement Trajectories ◽  
Natural Motion ◽  
Upper Limb Prosthesis ◽  
Natural Movement ◽  
Artificial Neural Network Ann ◽  
Analysis System

The motion of the current prostheses is sequential and does not allow natural movements. In this work, complex natural motion patterns from a healthy upper limb were characterized in order to be emulated for a trans-humeral prosthesis with three degrees of freedom at the elbow. Firstly, it was necessary to define the prosthesis workspace, which means to establish a relationship using an artificial neural network (ANN), between the arm-forearm (3-D) angles allowed by the prosthesis, and its actuators length. The 3-D angles were measured between the forearm and each axis of the reference system attached at the elbow. Secondly, five activities of daily living (ADLs) were analyzed by means of the elbow flexion (EF), the forearm prono-supination (FPS) and the 3-D angles, from healthy subjects, by using a video-based motion analysis system. The 3-D angles were fed to the prosthesis model (ANN) in order to analyze which ADLs could be emulated by the prosthesis. As a result, a prosthesis kinematics approximation was obtained. In conclusion, in spite of the innovative mechanical configuration of the actuators, it was possible to carry out only three of the five ADLs considered. Future work will include improvement of the mechanical configuration of the prosthesis to have greater range of motion.

scholarly journals A Solution of the Inverse Kinematics Problem for a 7-Degrees-of-Freedom Serial Redundant Manipulator Using Gröbner Bases Theory

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Sérgio Ricardo Xavier da Silva ◽  
Leizer Schnitman ◽  
Vitalino Cesca Filho
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Gröbner Bases ◽  
Grobner Bases ◽  
Operational Performance ◽  
Redundant Manipulators ◽  
Redundant Manipulator ◽  
All Solutions ◽  
Inverse Kinematics Problem ◽  
Algebraic Computing

This article presents a solution of the inverse kinematics problem of 7-degrees-of-freedom serial redundant manipulators. A 7-degrees-of-freedom (7-DoF) redundant manipulator can avoid obstacles and thus improve operational performance. However, its inverse kinematics is difficult to solve since it has one more DoF than that necessary for reaching the whole workspace, which causes infinite solutions. In this article, Gröbner bases theory is proposed to solve the inverse kinematics. First, the Denavit–Hartenberg model for the manipulator is established. Second, different joint configurations are obtained using Gröbner bases theory. All solutions are confirmed with the aid of algebraic computing software, confirming that this method is accurate and easy to be implemented.

scholarly journals Joint Space Redundancy Resolution of Serial Link Manipulator: An Inverse Kinematics and Continuum Structure Numerical Approach

2020 ◽  
Author(s):  
Toshit Jain ◽  
Jinesh Kumar Jain ◽  
Debanik Roy
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Complex Structure ◽  
Initial Approximation ◽  
Joint Space ◽  
Primary Objective ◽  
Target Point ◽  
Redundancy Resolution ◽  
Redundant Manipulator ◽  
Serial Link

Automatic control to any of robot manipulators, some kind of issues are being observed. A numerical method for solution generation to the inverse kinematics problem of redundant robotic manipulators is presented to obtain the smoothest algorithm as possible, leading to a robust iterative method. After the primary objective of the reachability of end-effectors to the target point is achieved, the aim is set to resolve the redundant degrees of freedom of redundant manipulator. This method is numerically stable since it converges to the correct answer with virtually any initial approximation, and it is not sensitive to the singular configurations of the manipulator. In addition, this technique is computationally effective and able to apply for serial manipulators with any DOF applications. A planar 3R-DOF serial link redundant manipulator is considered as exemplar problem for solving. Also, the continuum approach for resolving more complex structure with variable DoF is illustrated here and their brief applicability to support surgeries and adaptive use of artificial linkage moments is also calculated.

scholarly journals Voice Recognition and Inverse Kinematics Control for a Redundant Manipulator Based on a Multilayer Artificial Intelligence Network

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Mai Ngoc Anh ◽  
Duong Xuan Bien
Keyword(s):  
Artificial Intelligence ◽  
Deep Learning ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Voice Recognition ◽  
Learning Model ◽  
Redundant Manipulator ◽  
Efficient Operation ◽  
Inverse Kinematics Problem ◽  
Deep Learning Model

This study presents the construction of a Vietnamese voice recognition module and inverse kinematics control of a redundant manipulator by using artificial intelligence algorithms. The first deep learning model is built to recognize and convert voice information into input signals of the inverse kinematics problem of a 6-degrees-of-freedom robotic manipulator. The inverse kinematics problem is solved based on the construction and training. The second deep learning model is built using the data determined from the mathematical model of the system’s geometrical structure, the limits of joint variables, and the workspace. The deep learning models are built in the PYTHON language. The efficient operation of the built deep learning networks demonstrates the reliability of the artificial intelligence algorithms and the applicability of the Vietnamese voice recognition module for various tasks.

Psychophysical Cost Function of Joint Movement for Arm Reach Posture Prediction

1994 ◽  
Vol 38 (10) ◽  
pp. 636-640 ◽  
Author(s):  
Eui S. Jung ◽  
Jaeho Choe ◽  
Sung H. Kim
Keyword(s):  
Prediction Model ◽  
Cost Function ◽  
Degrees Of Freedom ◽  
Human Movement ◽  
Difficult Problem ◽  
Joint Torque ◽  
Joint Movement ◽  
Human Arm ◽  
Posture Prediction ◽  
Joint Range

A man model can be used as an effective tool to design ergonomically sound products and workplaces, and subsequently evaluate them properly. For a man model to be truly useful, it must be integrated with a posture prediction model which should be capable of representing the human arm reach posture in the context of equipments and workspaces. Since the human movement possesses redundant degrees of freedom, accurate representation or prediction of human movement was known to be a difficult problem. To solve this redundancy problem, a psychophysical cost function was suggested in this study which defines a cost value for each joint movement angle. The psychophysical cost function developed integrates the psychophysical discomfort of joints and the joint range availability concept which has been used for redundant arm manipulation in robotics to predict the arm reach posture. To properly predict an arm reach posture, an arm reach posture prediction model was then developed in which a posture configuration that provides the minimum total cost is chosen. The predictivity of the psychophysical cost function was compared with that of the biomechanical cost function which is based on the minimization of joint torque. Here, the human body is regarded as a two-dimensional multi-link system which consists of four links; trunk, upper arm, lower arm and hand. Real reach postures were photographed from the subjects and were compared to the postures predicted by the model. Results showed that the postures predicted by the psychophysical cost function closely simulated human reach postures and the predictivity was more accurate than that by the biomechanical cost function.

Kinematical Analysis and Simulation of Upper Limb Rehabilitation Robot

2011 ◽  
Vol 474-476 ◽  
pp. 1315-1320
Author(s):  
Xiang Li Cheng ◽  
Yi Qi Zhou ◽  
Cui Peng Zuo ◽  
Xiao Hua Fan
Keyword(s):  
Upper Limb ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Mechanical Design ◽  
Rehabilitation Medicine ◽  
Algebraic Solution ◽  
Rehabilitation Robot ◽  
Upper Limb Rehabilitation ◽  
Kinematical Analysis ◽  
Limb Rehabilitation

To assist stroke patients with rehabilitation training, an upper limb rehabilitation robot with an exoskeleton structure and three degrees of freedom (DOF) was developed in this paper. Under the guidance of the theory of rehabilitation medicine, the mechanical design of the robot was completed. Then, the kinematics equations were established by means of homogeneous transformation, including the forward kinematics and the inverse kinematics. The kinematical analysis was carried out and the algebraic solution of inverse kinematics was derived, which provided a theoretical basis for realizing the intelligent control. To validate the performance, the kinematical simulation was conducted, and the simulation results showed that the design of the exoskeleton robot was feasible.

scholarly journals Development of a Dynamic Oriented Rehabilitative Integrated System (DORIS) and Preliminary Tests

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3402 ◽  
Author(s):  
Summa ◽  
Gori ◽  
Freda ◽  
Castelli ◽  
Petrarca
Keyword(s):  
Degrees Of Freedom ◽  
Ad Hoc ◽  
Position Control ◽  
Transmission Control Protocol ◽  
Integrated System ◽  
Moving Platforms ◽  
Custom Design ◽  
The Subject ◽  
Supporting Plate ◽  
Analysis System

Moving platforms were introduced in the field of the study of posturography since the 1970s. Commercial platforms have some limits: a limited number of degrees of freedom, pre-configured protocols, and, usually, they are expensive. In order to overcome these limits, we developed a robotic platform: Dynamic Oriented Rehabilitative Integrated System (DORIS). We aimed at realizing a versatile solution that can be applied both for research purposes but also for personalizing the training of equilibrium and gait. We reached these goals by means of a Stewart platform that was realized with linear actuators and a supporting plate. Each actuator is provided by an ad hoc built monoaxial load cell. Position control allows a large range of movements and load cells measure the reactive force applied by the subject. Transmission Control Protocol/Internet Protocol (TCP/IP) guarantees the communication between the platform and other systems. We integrated DORIS with a motion analysis system, an electromyography (EMG) system, and a virtual reality environment (VR). This integration and the custom design of the platform offer the opportunity to manipulate the available information of the subject under analysis, which uses visual, vestibular, and plantar feet pressure inputs. The full access to the human movements and to the dynamic interaction is a further benefit for the identification of innovative solutions for research and physical rehabilitation purposes in a field that is widely investigated but still open.

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