A Model of the Human Spine: Forward and Inverse Kinematics

1992 ◽  
Author(s):  
Sunil Kumar Agrawal ◽  
Siyan Li ◽  
Glen Desmier
Keyword(s):  
Range Of Motion ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Joint Angles ◽  
Human Spine ◽  
Forward And Inverse Kinematics ◽  
Position And Orientation ◽  
Three Degrees Of Freedom ◽  
Adjacent Vertebra

Abstract The human spine is a sophisticated mechanism consisting of 24 vertebrae which are arranged in a series-chain between the pelvis and the skull. By careful articulation of these vertebrae, a human being achieves fine motion of the skull. The spine can be modeled as a series-chain with 24 rigid links, the vertebrae, where each vertebra has three degrees-of-freedom relative to an adjacent vertebra. From the studies in the literature, the vertebral geometry and the range of motion between adjacent vertebrae are well-known. The objectives of this paper are to present a kinematic model of the spine using the available data in the literature and an algorithm to compute the inter vertebral joint angles given the position and orientation of the skull. This algorithm is based on the observation that the backbone can be described analytically by a space curve which is used to find the joint solutions..

Kinematic Analysis of a Three-DOF Parallel Mechanism for Telescope Applications

1997 ◽  
Author(s):  
J. A. Carretero ◽  
M. Nahon ◽  
B. Buckham ◽  
C. M. Gosselin
Keyword(s):  
Kinematic Analysis ◽  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Jacobian Matrix ◽  
Constraint Equations ◽  
Forward And Inverse Kinematics ◽  
Position And Orientation ◽  
Three Degree Of Freedom ◽  
Three Degrees Of Freedom

Abstract This paper presents a kinematic analysis of a three-degree-of-freedom parallel mechanism intended for use as a telescope mirror focussing device. The construction of the mechanism is first described and its forward and inverse kinematics solutions are derived. Because the mechanism has only three degrees of freedom, constraint equations must be generated to describe the inter-relationship between the six Cartesian coordinates which describe the position and orientation of the moving platform. Once these constraints are incorporated into the kinematics model, a constrained Jacobian matrix is obtained. The stiffness and dexterity properties of the mechanism are then determined based on this Jacobian matrix. The mechanism is shown to exhibit desirable properties in the region of its workspace of interest in the telescope focussing application.

Accuracy estimation of a stretch-retractable single section continuum manipulator based on inverse kinematics

2019 ◽  
Vol 46 (5) ◽  
pp. 573-580
Author(s):  
Hao Wang ◽  
GuoHua Gao ◽  
Qixiao Xia ◽  
Han Ren ◽  
LianShi Li ◽  
...  
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Content Type ◽  
Kinematics Model ◽  
Six Degrees Of Freedom ◽  
Single Section ◽  
Motion Range ◽  
Continuum Manipulator ◽  
Three Degrees Of Freedom

Purpose The purpose of this paper is to present a novel stretch-retractable single section (SRSS) continuum manipulator which owns three degrees of freedom and higher motion range in three-dimension workspace than regular single continuum manipulator. Moreover, the motion accuracy was analyzed based on the kinematic model. In addition, the experiments were carried out for validation of the theory. Design/methodology/approach A kinematics model of the SRSS continuum manipulator is presented for analysis on bending, rotating and retracting in its workspace. To discuss the motion accuracy of the SRSS continuum manipulator, the dexterity theory was introduced based on the decomposing of the Jacobian matrix. In addition, the accuracy of motion is estimated based on the inverse kinematics and dexterity theory. To verify the presented theory, the motion of free end was tracked by an electromagnetic positioning system. According to the comparison of experimental value and theoretical analysis, the free end error of SRSS continuum manipulator is less than 6.24 per cent in the region with favorable dexterity. Findings This paper presents a new stretch-retractable continuum manipulator that the structure was composed of several springs as the backbone. Thus, the SRSS continuum manipulator could own wide motion range depending on its retractable structure. Then, the motion accuracy character of the SRSS continuum manipulator in the different regions of its workspace was obtained both theoretically and experimentally. The results show that the high accuracy region distributes in the vicinity of the outer boundary of the workspace. The motion accuracy gradually decreases with the motion position approaching to the center of its workspace. Research limitations/implications The presented SRSS continuum manipulator owns three degrees of freedom. The future work would be focused on the two-section structure which will own six degrees of freedom. Practical implications In this study, the SRSS continuum manipulator could be extended to six degrees of freedom continuum robot with two sections that is less one section than regular six degrees of freedom with three single section continuum manipulator. Originality/value The value of this study is to propose a SRSS continuum manipulator which owns three degrees of freedom and could stretch and retract to expend workspace, for which the accuracy in different regions of the workspace was analyzed and validated based on the kinematics model and experiments. The results could be feasible to plan the motion space of the SRSS continuum manipulator for keeping in suitable accuracy region.

scholarly journals Nonanthropomorphic exoskeleton with legs based on eight-bar linkages

2018 ◽  
Vol 15 (1) ◽  
pp. 172988141875577 ◽  
Author(s):  
Jorge Curiel Godoy ◽  
Ignacio Juárez Campos ◽  
Lucia Márquez Pérez ◽  
Leonardo Romero Muñoz
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Main Function ◽  
Polynomial Functions ◽  
Forward And Inverse Kinematics ◽  
And Performance ◽  
The Stability ◽  
Robotic Leg ◽  
Three Degrees Of Freedom ◽  
Difficulty Walking

This article presents the principles upon which a new nonanthropomorphic biped exoskeleton was designed, whose legs are based on an eight-bar mechanism. The main function of the exoskeleton is to assist people who have difficulty walking. Every leg is based on the planar Peaucellier–Lipkin mechanism, which is a one degree of freedom linkage. To be used as a robotic leg, the Peaucellier–Lipkin mechanism was modified by including two more degrees of freedom, as well as by the addition of a mechanical system based on toothed pulleys and timing belts that provides balance and stability to the user. The use of the Peaucellier–Lipkin mechanism, its transformation from one to three degrees of freedom, and the incorporation of the stability system are the main innovations and contributions of this novel nonanthropomorphic exoskeleton. Its mobility and performance are also presented herein, through forward and inverse kinematics, together with its application in carrying out the translation movement of the robotic foot along paths with the imposition of motion laws based on polynomial functions of time.

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.

A Hybrid Self-Stressed Cable-Driven Mechanism

2008 ◽  
Author(s):  
Saeed Behzadipour
Keyword(s):  
Static Loading ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Tensile Force ◽  
Cable System ◽  
End Effector ◽  
Stiffness Analysis ◽  
Cable Length ◽  
Cable Drive ◽  
Forward And Inverse Kinematics

A new hybrid cable-driven manipulator is introduced. The manipulator is composed of a Cartesian mechanism to provide three translational degrees of freedom and a cable system to drive the mechanism. The end-effector is driven by three rotational motors through the cables. The cable drive system in this mechanism is self-stressed meaning that the pre-tension of the cables which keep them taut is provided internally. In other words, no redundant actuator or external force is required to maintain the tensile force in the cables. This simplifies the operation of the mechanism by reducing the number of actuators and also avoids their continuous static loading. It also eliminates the redundant work of the actuators which is usually present in cable-driven mechanisms. Forward and inverse kinematics problems are solved and shown to have explicit solutions. Static and stiffness analysis are also performed. The effects of the cable’s compliance on the stiffness of the mechanism is modeled and presented by a characteristic cable length. The characteristic cable length is calculated and analyzed in representative locations of the workspace.

scholarly journals Analytical inverse kinematics for 5-DOF humanoid manipulator under arbitrarily specified unconstrained orientation of end-effector

Robotica ◽  
2014 ◽  
Vol 33 (4) ◽  
pp. 747-767 ◽  
Author(s):  
Masayuki Shimizu
Keyword(s):  
Analytical Method ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Singularity Analysis ◽  
Inverse Kinematic ◽  
Inverse Kinematic Problem ◽  
Target Orientation ◽  
End Effector ◽  
Position And Orientation

SUMMARYThis paper proposes an analytical method of solving the inverse kinematic problem for a humanoid manipulator with five degrees-of-freedom (DOF) under the condition that the target orientation of the manipulator's end-effector is not constrained around an axis fixed with respect to the environment. Since the number of the joints is less than six, the inverse kinematic problem cannot be solved for arbitrarily specified position and orientation of the end-effector. To cope with the problem, a generalized unconstrained orientation is introduced in this paper. In addition, this paper conducts the singularity analysis to identify all singular conditions.

HOLONOMIC AND OMNIDIRECTIONAL LOCOMOTION SYSTEMS FOR WHEELED MOBILE ROBOTS: A REVIEW

2015 ◽  
Vol 77 (28) ◽  
Author(s):  
M. Juhairi Aziz Safar
Keyword(s):  
Mobile Robot ◽  
Mobile Robots ◽  
Degrees Of Freedom ◽  
Wheeled Mobile Robot ◽  
Arbitrary Direction ◽  
Current Position ◽  
Wheeled Mobile Robots ◽  
Future Improvement ◽  
Position And Orientation ◽  
Three Degrees Of Freedom

Holonomic and omnidirectional locomotion systems are best known for their capability to maneuver at any arbitrary direction regardless of their current position and orientation with a three degrees of freedom mobility. This paper summarizes the advancement of holonomic and omnidirectional locomotion systems for wheeled mobile robot applications and discuss the issues and challenges for future improvement.

Orientation Workspace Analysis of a Novel 3SPS+1PS Symmetrical Parallel Manipulator Based on Unit Quaternion

2011 ◽  
Vol 201-203 ◽  
pp. 1849-1853
Author(s):  
Jing Li Yu ◽  
Gang Cheng ◽  
Shuai Zhang ◽  
De Kun Zhang
Keyword(s):  
Inverse Kinematics ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Unit Quaternion ◽  
Structure Characteristics ◽  
Workspace Analysis ◽  
Moving Platform ◽  
Position And Orientation ◽  
4 Degrees Of Freedom ◽  
Orientation Workspace

For a novel 3SPS+1PS parallel manipulator with 4 degrees of freedom including three rotations and one translation, the formulae for solving the inverse kinematics equations are derived based on quaternion method. Unit quaternion is used to represent the position and orientation of moving platform, and the singularities caused by Euler angles are avoided. Combining the topological structure characteristics of the parallel manipulator, it only has three rotations when its moving platform is at a given translation position. Based on the inverse position/pose equations and the all the constraints of the parallel manipulator, the discrete algorithm for the orientation workspaces of 3SPS+1PS parallel manipulator where the moving platform is at some different given translation positions are designed. The research builds the theoretical basis for optimizing the orientation workspace with given position.

scholarly journals Design and analysis of a 3-DOF planar micromanipulation stage with large rotational displacement for micromanipulation system

2017 ◽  
Vol 8 (1) ◽  
pp. 117-126 ◽  
Author(s):  
Bingxiao Ding ◽  
Yangmin Li ◽  
Xiao Xiao ◽  
Yirui Tang ◽  
Bin Li
Keyword(s):  
Nanoimprint Lithography ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Rotational Displacement ◽  
Revolute Joints ◽  
Kinematic Models ◽  
Lever Mechanism ◽  
Three Degrees Of Freedom

Abstract. Flexure-based mechanisms have been widely used for scanning tunneling microscopy, nanoimprint lithography, fast servo tool system and micro/nano manipulation. In this paper, a novel planar micromanipulation stage with large rotational displacement is proposed. The designed monolithic manipulator has three degrees of freedom (DOF), i.e. two translations along the X and Y axes and one rotation around Z axis. In order to get a large workspace, the lever mechanism is adopted to magnify the stroke of the piezoelectric actuators and also the leaf beam flexure is utilized due to its large rotational scope. Different from conventional pre-tightening mechanism, a modified pre-tightening mechanism, which is less harmful to the stacked actuators, is proposed in this paper. Taking the circular flexure hinges and leaf beam flexures hinges as revolute joints, the forward kinematics and inverse kinematics models of this stage are derived. The workspace of the micromanipulator is finally obtained, which is based on the derived kinematic models.

Kinematic Analysis of a New 3-DOF Translational Parallel Manipulator

2005 ◽  
Author(s):  
Yangmin Li ◽  
Qingsong Xu
Keyword(s):  
Inverse Kinematics ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Screw Theory ◽  
Industrial Applications ◽  
Forward Kinematics ◽  
Physical Constraints ◽  
Mechanical Joints ◽  
Reachable Workspace ◽  
Three Degrees Of Freedom

A novel three-degrees-of-freedom (3-DOF) translational parallel manipulator (TPM) with orthogonally arranged fixed actuators is proposed in this paper. The mobility of the manipulator is analyzed via screw theory. The inverse kinematics, forward kinematics, and velocity analyses are performed and the singularities and isotropic configurations are investigated in details afterwards. Under different cases of physical constraints imposed by mechanical joints, the reachable workspace of the manipulator is geometrically generated and compared. Especially, it is illustrated that the manipulator in principle possesses a fairly regular like workspace with a maximum cuboid defined as the usable workspace inscribed and one isotropic configuration involved. Furthermore, the singularity within the usable workspace is verified, and simulation results show that there exist no any singular configurations within the specified workspace. Therefore, the presented new manipulator has a great potential for high precision industrial applications such as assembly, machining, etc.

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