Singularity analysis of a 7-DOF spatial hybrid manipulator for medical surgery

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sameer Gupta ◽  
Ekta Singla ◽  
Sanjeev Soni ◽  
Ashish Singla
Keyword(s):  
Degrees Of Freedom ◽  
Closed Loop ◽  
Singularity Analysis ◽  
Medical Surgery ◽  
Natural Motion ◽  
Hybrid Manipulator ◽  
Contour Plots ◽  
Kinematic Singularities ◽  
And Control ◽  
Optimal Configurations

Abstract This paper presents the singularity analysis of a 7-degrees of freedom (DOF) hybrid manipulator consisting of a closed-loop within it. From the past studies, it is well-known that the kinematic singularities play a significant role in the design and control of robotic manipulators. Kinematic singularities pose two-fold effects – first, they can induce the loss of one or more DOF of the manipulator and cause infinite joint rates at that particular joint, and second, they help to determine the trajectory or zone with high mechanical advantage. In current work, a 7-DOF hybrid manipulator is considered which is being developed at Council Of Scientific And Industrial Research–Central Scientific Instruments Organisation (CSIR–CSIO) Chandigarh to assist a surgeon during a medical-surgical task. To emulate the natural motion of a surgeon, the challenging configuration with redundant DOF is utilized. Jacobian has been computed analytically and analyzed at each instantaneous configuration with the evaluation of manipulability. Effect of a closed loop in the hybrid configurations is focused at, and utilizing the contour plots, good and worst working zones are identified in the workspace of the manipulator. The verification and validation of best and worst manipulability points (singularities) are done with the help of genetic algorithms, to determine locally and globally optimal configurations. Finally, on the basis of the singularity analysis, the present work concludes with few guidelines to the surgeon about the best and worst working zones for surgical tasks.

Singularity Analysis of a Novel 4-DOFs Parallel Robot H4 by Using Screw Theory

2003 ◽  
Author(s):  
Hee-Byoung Choi ◽  
Atsushi Konno ◽  
Masaru Uchiyama
Keyword(s):  
Closed Loop ◽  
Jacobian Matrix ◽  
Screw Theory ◽  
Parallel Robot ◽  
Singularity Analysis ◽  
Loop Structure ◽  
Singular Configurations ◽  
Planning And Control ◽  
Kinematic Singularities ◽  
And Control

The closed-loop structure of a parallel robot results in complex kinematic singularities in the workspace. Singularity analysis become important in design, motion, planning, and control of parallel robot. The traditional method to determine a singular configurations is to find the determinant of the Jacobian matrix. However, the Jacobian matrix of a parallel manipulator is complex in general, and thus it is not easy to find the determinant of the Jacobian matrix. In this paper, we focus on the singularity analysis of a novel 4-DOFs parallel robot H4 based on screw theory. Two types singularities, i.e., the forward and inverse singularities, have been identified.

Singularity Analysis of Closed Kinematic Chains

1999 ◽  
Vol 121 (1) ◽  
pp. 32-38 ◽  
Author(s):  
F. C. Park ◽  
J. W. Kim
Keyword(s):  
Configuration Space ◽  
Degrees Of Freedom ◽  
Geometric Analysis ◽  
Singularity Analysis ◽  
Geometric Framework ◽  
End Effector ◽  
Kinematic Chains ◽  
Closed Chain ◽  
High Level ◽  
Kinematic Singularities

This paper presents a coordinate-invariant differential geometric analysis of kinematic singularities for closed kinematic chains containing both active and passive joints. Using the geometric framework developed in Park and Kim (1996) for closed chain manipulability analysis, we classify closed chain singularities into three basic types: (i) those corresponding to singular points of the joint configuration space (configuration space singularities), (ii) those induced by the choice of actuated joints (actuator singularities), and (iii) those configurations in which the end-effector loses one or more degrees of freedom of available motion (end-effector singularities). The proposed geometric classification provides a high-level taxonomy for mechanism singularities that is independent of the choice of local coordinates used to describe the kinematics, and includes mechanisms that have more actuators than kinematic degrees of freedom.

Design of Materials and Mechanisms for Responsive Robots

2018 ◽  
Vol 1 (1) ◽  
pp. 359-384 ◽  
Author(s):  
Elliot W. Hawkes ◽  
Mark R. Cutkosky
Keyword(s):  
Genetic Algorithms ◽  
Energy Storage ◽  
Environmental Conditions ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
Open Loop ◽  
Challenging Problem ◽  
Manufacturing Applications ◽  
The Stability ◽  
And Control

As robots move beyond manufacturing applications to less predictable environments, they can increasingly benefit, as animals do, from integrating sensing and control with the passive properties provided by particular combinations and arrangements of materials and mechanisms. This realization is partly responsible for the recent proliferation of soft and bioinspired robots. Tuned materials and mechanisms can provide several kinds of benefits, including energy storage and recovery, increased physical robustness, and decreased response time to sudden events. In addition, they may offer passive open-loop behaviors and responses to external changes in loading or environmental conditions. Collectively, these properties can also increase the stability of a robot as it interacts with the environment and allow the closed-loop controller to reduce the apparent degrees of freedom subject to control. The design of appropriate materials and mechanisms remains a challenging problem; bioinspiration, genetic algorithms, and numerical shape and materials optimization are all applicable. New multimaterial fabrication processes are also steadily increasing the range and magnitude of passive properties available for intrinsically responsive robots.

Design and Control of a Hydraulic Human Power Amplifier

2004 ◽  
Author(s):  
Perry Y. Li
Keyword(s):  
Power Amplifier ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
Parametric Uncertainties ◽  
Hydraulic Actuator ◽  
Closed Loop System ◽  
Static Loads ◽  
Human Power ◽  
Compression Spring ◽  
And Control

This paper describes the design of and some preliminary control results for a hydraulically actuated human power amplifier. The system is in the form of an oar, with its reach and pitch degrees of freedom being hydraulically assisted. A robust PI force controller is proposed so that the hydraulic actuator force tracks a scaled copy of the force exerted by the human. Nonlinearities and uncertainties in the compression spring, as well as parametric uncertainties are taken into account. The passivity property of the closed loop system is also analyzed. The controller has been tested in simulations and experimentally. It is shown to be effective when pushing against an object, and in assisting in bearing static loads.

Payload sway suppression in rotary cranes by digital filtering of the commanded inputs

2003 ◽  
Vol 217 (2) ◽  
pp. 99-109 ◽  
Author(s):  
G Glossiotis ◽  
I Antoniadis
Keyword(s):  
Energy Efficient ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
Finite Impulse Response ◽  
Dynamic Modelling ◽  
Practical Application ◽  
Loop Control ◽  
Rotary Crane ◽  
Time And Energy ◽  
And Control

A method is proposed for the suppression of the sway of rotary crane payloads. In contrast to closed-loop control methods which encounter significant practical application problems, the proposed method is based simply on the preprocessing of all the commanded crane inputs by a properly designed finite impulse response (FIR) filter. A four-degrees-of-freedom (4DOF) model for the rotary crane system is considered, incorporating both the hoisting and the slewing motions and thus able to handle cases where hoisting can be simultaneously applied to the rotary motion. Although the resulting dynamic system is strongly non-linear and time varying, the method is shown effectively to suppress, in a quite robust, time and energy efficient way, both the transient as well as the residual sway of the payload. Moreover, additional advantages of the proposed method are that no dynamic modelling of the crane is required, and that the applicability of the method is quite easy and general, without the need for any additional instrumentation and control equipment.

Kinematics and Singularity Analysis of a Four-Degree-of-Freedom Serial-Parallel Hybrid Manipulator

2017 ◽  
Vol 29 (3) ◽  
pp. 520-527 ◽  
Author(s):  
Guangying Ma ◽  
◽  
Yuan Chen ◽  
Yunlong Yao ◽  
Jun Gao
Keyword(s):  
Parallel Mechanism ◽  
Jacobian Matrix ◽  
Screw Theory ◽  
Singularity Analysis ◽  
Degree Of Freedom ◽  
Independent Variables ◽  
Working Environments ◽  
Hybrid Manipulator ◽  
Parallel Hybrid ◽  
Kinematic Singularities

[abstFig src='/00290003/07.jpg' width='300' text='4DOF serial-parallel hybrid manipulator' ] For adapting to the complex working environments of amphibious manipulators, we proposed a serial-parallel hybrid quadruped walking manipulator. We simplified the leg mechanism of the serial-parallel hybrid manipulator as a 2UPU-UPR parallel mechanism, and then analyzed the degree of freedom (DOF) of the parallel mechanism by using the screw theory. The results show that the position of the<span class=”bold”>Y</span>direction and the pose of the<span class=”bold”>Z</span>direction are two independent variables which influence the mechanism movement. We deduced the kinematics inverse solution and the velocity Jacobian matrix of the 2UPU-UPR parallel mechanism. Based on the analysis of the Jacobian matrix, three kinds of kinematic singularities of the 2UPU-UPR parallel mechanism are identified. The results show that the 2UPU-UPR parallel mechanism doesn’t have the kinematic inverse singularity, but it has three kinds of kinematic forward singularities and two kinds of combined singularities. Finally, the variation of motorial parameters of this 2UPU-UPR parallel mechanism was discussed by a calculation example.

Control of processing at multi-tool two-support setup

2020 ◽  
pp. 67-73
Author(s):  
N.D. YUsubov ◽  
G.M. Abbasova
Keyword(s):  
Degrees Of Freedom ◽  
Factor Model ◽  
Angular Displacement ◽  
Factor Models ◽  
Technological System ◽  
Displacement Control ◽  
Model Accuracy ◽  
Six Degrees Of Freedom ◽  
Angular Displacements ◽  
And Control

The accuracy of two-tool machining on automatic lathes is analyzed. Full-factor models of distortions and scattering fields of the performed dimensions, taking into account the flexibility of the technological system on six degrees of freedom, i. e. angular displacements in the technological system, were used in the research. Possibilities of design and control of two-tool adjustment are considered. Keywords turning processing, cutting mode, two-tool setup, full-factor model, accuracy, angular displacement, control, calculation [email protected]

scholarly journals Design, Construction, and Control for an Underwater Vehicle Type Sepiida

Robotica ◽  
2020 ◽  
pp. 1-18
Author(s):  
M. Garcia ◽  
P. Castillo ◽  
E. Campos ◽  
R. Lozano
Keyword(s):  
Embedded System ◽  
Closed Loop ◽  
Underwater Vehicle ◽  
Mathematical Representation ◽  
Closed Loop System ◽  
Vehicle Type ◽  
Mathematical Equations ◽  
And Control ◽  
Design Construction

SUMMARY A novel underwater vehicle configuration with an operating principle as the Sepiida animal is presented and developed in this paper. The mathematical equations describing the movements of the vehicle are obtained using the Newton–Euler approach. An analysis of the dynamic model is done for control purposes. A prototype and its embedded system are developed for validating analytically and experimentally the proposed mathematical representation. A real-time characterization of one mass is done to relate the pitch angle with the radio of displacement of the mass. In addition, first validation of the closed-loop system is done using a linear controller.

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