An Analytical Tension Model for Continuum Robots with n Generally Positioned Tendons

2019 ◽  
Vol 04 (03n04) ◽  
pp. 1942003
Author(s):  
Mohsen Moradi Dalvand ◽  
Saeid Nahavandi ◽  
Robert D. Howe
Keyword(s):  
Stereo Vision ◽  
Control Algorithm ◽  
Open Loop ◽  
Open Loop Control ◽  
Continuum Robots ◽  
Loop Control ◽  
Proposed Model ◽  
Continuum Robot ◽  
Tension Loading ◽  
Tendon Compliance

The estimation of tension loads in multi-tendon continuum robots or catheters plays an important role not only in the design process but also in the control algorithm to avoid slack. An analytical tension loading model is developed that, for any given beam configuration within the workspace, calculates tendon tensions in [Formula: see text]-tendon continuum robots with general tendon positioning. The model accounts for the bending and axial compliance of the manipulator as well as tendon compliance. A 6-tendon continuum robot integrated with a stereo vision-based 3D reconstruction system is utilized to experimentally validate the proposed analytical model in open-loop control architecture. The proposed model demonstrates around 95% accuracy in estimating tendon tensions in a continuum robot with general tendon positioning and axial stretch in its tendons for all of the trials and experiments.

Follow-the-leader motion strategy for multi-section continuum robots based on differential evolution algorithm

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
GuoHua Gao ◽  
Pengyu Wang ◽  
Hao Wang
Keyword(s):  
Differential Evolution ◽  
Kinematic Model ◽  
Differential Evolution Algorithm ◽  
Open Loop ◽  
Continuum Robots ◽  
Content Type ◽  
Loop Control ◽  
Continuum Robot ◽  
Motion Strategy ◽  
The Continuum

Purpose The purpose of this paper is to present a follow-the-leader motion strategy for multi-section continuum robots, which aims to make the robot have the motion ability in a confined environment and avoid a collision. Design/methodology/approach First, the mechanical design of a multi-section continuum robot is introduced and the forward kinematic model is built. After that, the follow-the-leader motion strategy is proposed and the differential evolution (DE) algorithm for calculating optimal posture parameters is presented. Then simulations and experiments are carried out on a series of predefined paths to analyze the performance of the follow-the-leader motion. Findings The follow-the-leader motion can be well performed on the continuum robots this study proposes in this research. The experimental results show that the deviation from the path is less than 9.7% and the tip error is no more than 15.6%. Research limitations/implications Currently, the follow-the-leader motion is affected by the following factors such as gravity and continuum robot design. Furthermore, the position error is not compensated under open-loop control. In future work, this paper will improve the accuracy of the robot and introduce a closed-loop control strategy to improve the motion accuracy. Originality/value The main contribution of this paper is to present an algorithm to generate follow-the-leader motion of the continuum robot based on DE. This method is suitable for solving new arrangements in the process of following a nonlinear path. Then, it is expected to promote the engineering application of the continuum robot.

scholarly journals Interleaved DC-DC Converter with Discrete Duty Cycle and Open Loop Control

2016 ◽  
Vol 53 (4) ◽  
pp. 14-21
Author(s):  
K. Kroics ◽  
A. Sokolovs
Keyword(s):  
Duty Cycle ◽  
Control Algorithm ◽  
Open Loop ◽  
Current Loop ◽  
Open Loop Control ◽  
Output Current ◽  
Loop Control ◽  
Control Principle ◽  
Conduction Mode ◽  
Current Ripple

Abstract The authors present the control principle of the multiphase interleaved DC-DC converter that can be used to vastly reduce output current ripple of the converter. The control algorithm can be easily implemented by using microcontroller without current loop in each phase. The converter works in discontinuous conduction mode (DCM) but close to boundary conduction mode (BCM). The DC-DC converter with such a control algorithm is useful in applications that do not require precise current adjustment. The prototype of the converter has been built. The experimental results of the current ripple are presented in the paper.

Motion Control Analysis of the Fruit-Trees Robot

2011 ◽  
Vol 135-136 ◽  
pp. 1179-1182
Author(s):  
Jia Ao Yu ◽  
Min Cang Fu
Keyword(s):  
Pid Control ◽  
Control Algorithm ◽  
Response Speed ◽  
Fruit Trees ◽  
Open Loop ◽  
Control Analysis ◽  
Open Loop Control ◽  
Loop Control ◽  
Straight Line ◽  
Motor Control System

The article tracks the fruit-trees robot, and analyzes the fruit-trees robot’s dual-motor control system. Based on the speed incremental PID closed-loop control algorithm of the step DC motor, the PID controller’s proportional coefficient, integral coefficient and differential coefficient is concluded. It demonstrates from the stimulations and experiments that the usage of speed incremental PID control do better at the response speed and stability than the open-loop control motor when the robot is run by a straight line on the ground at the 3000rpm.

Backup Nutation Damping Strategy for the Galileo Spacecraft

1991 ◽  
Vol 113 (2) ◽  
pp. 308-312
Author(s):  
F. O. Eke ◽  
E. M. Eke
Keyword(s):  
Motion Compensation ◽  
Control Algorithm ◽  
Open Loop ◽  
Remedial Measures ◽  
Open Loop Control ◽  
Spacecraft Motion ◽  
Loop Control ◽  
Compensation Algorithm

This paper discusses the design of remedial measures that can be taken to achieve reasonable nutation damping of the Galileo spacecraft in the event of failure of its boom damper in flight. One scheme exploits the effects of payload motion on the nutational stability of a spinning spacecraft. This scheme demands that the spacecraft motion compensation algorithm be enabled with the scan platform bore sight pointed in a well chosen direction to produce rapid damping of spacecraft nutation. A second method suggested for nutation damping is a thruster-based open loop control algorithm, utilizing a pair of thrusters as actuators.

scholarly journals Research on system modeling and motion control simulation of automatic power trowel

2021 ◽  
Vol 2125 (1) ◽  
pp. 012031
Author(s):  
Hao Xu ◽  
Yutian Zhu ◽  
Mo Chen ◽  
Zhao Liu
Keyword(s):  
Control Algorithm ◽  
Control Method ◽  
System Modeling ◽  
Open Loop ◽  
State Feedback Control ◽  
Open Loop Control ◽  
Loop Control ◽  
Point Motion ◽  
Point To Point ◽  
The Relationship

Abstract Aiming at the problems that the existing control researches on the power trowel are limited to the analysis of the motion principle and the open-loop control of some mechanisms, taking a hydraulically-driven ride-on power trowel as the research object, the closed-loop control method of the point-to-point motion of the power trowel is studied. After analyzing the motion principle of the power trowel, based on the assumption of elastic deformation of concrete, the dynamic model of a single trowel is established, and the relationship between the driving force, driving moment and hydraulic moment, velocity, and angular velocity of the trowel is obtained. The whole machine motion equation of the power trowel is deduced, the point-to-point state feedback control algorithm of the power trowel is studied, and a simulation model is built to verify the accuracy of the system model of the power trowel and the effectiveness of the control algorithm. This research can provide reference for the control method design of other complex motions of the power trowel.

Optimal Control of Nonlinear Structures

1988 ◽  
Vol 55 (4) ◽  
pp. 931-938 ◽  
Author(s):  
J. N. Yang ◽  
F. X. Long ◽  
D. Wong
Keyword(s):  
Optimal Control ◽  
Control Systems ◽  
Active Control ◽  
Control Algorithm ◽  
Open Loop ◽  
Control Algorithms ◽  
Nonlinear Structures ◽  
Open Loop Control ◽  
Loop Control ◽  
Optimal Control Algorithms

Three optimal control algorithms are proposed for reducing oscillations of flexible nonlinear structures subjected to general stochastic dynamic loads, such as earthquakes, waves, winds, etc. The optimal control forces are determined analytically by minimizing a time-dependent quadratic performance index, and nonlinear equations of motion are solved using the Wilson-θ numerical procedures. The optimal control algorithms developed for applications to nonlinear structures are referred to as the instantaneous optimal control algorithms, including the instantaneous optimal open-loop control algorithm, instantaneous optimal closed-loop control algorithm, and instantaneous optimal closed-open-loop control algorithm. These optimal algorithms are computationally efficient and suitable for on-line implementation of active control systems to realistic nonlinear structures. Numerical examples are worked out to demonstrate the applications of these optimal control algorithms to nonlinear structures. In particular, control of structures undergoing inelastic deformations under strong earthquake excitations are illustrated. The advantage of using combined passive/active control systems is also demonstrated.

Open-loop control of compensation for optical propagation through a turbulent shear flow

1998 ◽  
Author(s):  
C. Truman ◽  
Lenore McMackin ◽  
Robert Pierson ◽  
Kenneth Bishop ◽  
Ellen Chen
Keyword(s):  
Shear Flow ◽  
Open Loop ◽  
Turbulent Shear ◽  
Turbulent Shear Flow ◽  
Open Loop Control ◽  
Loop Control ◽  
Optical Propagation
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