Where in the world is the speed/accuracy trade-off?

<div>A method to assess the performance of closed loop control loops, based on closed-loop system identification. This method allows to take into account the trade-off between process variable and manipulated variable energy, thus overcoming one of the most important criticisms to Harris' index. </div>

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Optimal Joint Space Control Design of a Hydraulic Stewart Manipulator

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.58-60.2438 ◽

2011 ◽

Vol 58-60 ◽

pp. 2438-2441

Author(s):

Zhi Yong Qu ◽

Zheng Mao Ye

Keyword(s):

Closed Loop ◽

Kinematic Model ◽

Optimization Method ◽

Joint Space ◽

Phase Control ◽

Inverse Kinematic ◽

Iteration Algorithm ◽

Second Phase ◽

Closed Loop Control ◽

Loop Control

This paper presents an algorithm to develop a mission-based optimal joint space control for a Stewart manipulator. The proposed algorithm consists of two optimization phases. The first phase seeks an inverse kinematic model and controller for the closed loop control of a Stewart manipulator using a feedback value. The second phase optimally tunes the controller called amplitude phase control (apc) in order to meet special mission requirements. Iteration algorithm is used in this phase as the optimization method. The proposed amplitude phase control optimal joint space control shows the capability to reduce the error in tracking the sin signals.

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Closed-loop control of soft continuum manipulators under tip follower actuation

The International Journal of Robotics Research ◽

10.1177/0278364921997167 ◽

2021 ◽

pp. 027836492199716

Author(s):

Federico Campisano ◽

Simone Caló ◽

Andria A. Remirez ◽

James H. Chandler ◽

Keith L. Obstein ◽

...

Keyword(s):

Closed Loop ◽

Kinematic Model ◽

Path Following ◽

External Loading ◽

Closed Loop Control ◽

Loop Control ◽

Actuation System ◽

Control Scheme ◽

Continuum Manipulators ◽

Continuum Manipulator

Continuum manipulators, inspired by nature, have drawn significant interest within the robotics community. They can facilitate motion within complex environments where traditional rigid robots may be ineffective, while maintaining a reasonable degree of precision. Soft continuum manipulators have emerged as a growing subfield of continuum robotics, with promise for applications requiring high compliance, including certain medical procedures. This has driven demand for new control schemes designed to precisely control these highly flexible manipulators, whose kinematics may be sensitive to external loads, such as gravity. This article presents one such approach, utilizing a rapidly computed kinematic model based on Cosserat rod theory, coupled with sensor feedback to facilitate closed-loop control, for a soft continuum manipulator under tip follower actuation and external loading. This approach is suited to soft manipulators undergoing quasi-static deployment, where actuators apply a follower wrench (i.e., one that is in a constant body frame direction regardless of robot configuration) anywhere along the continuum structure, as can be done in water-jet propulsion. In this article we apply the framework specifically to a tip actuated soft continuum manipulator. The proposed control scheme employs both actuator feedback and pose feedback. The actuator feedback is utilized to both regulate the follower load and to compensate for non-linearities of the actuation system that can introduce kinematic model error. Pose feedback is required to maintain accurate path following. Experimental results demonstrate successful path following with the closed-loop control scheme, with significant performance improvements gained through the use of sensor feedback when compared with the open-loop case.

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Multi-criteria performance assessment based on closed-loop system identification

10.36227/techrxiv.16817551 ◽

2021 ◽

Author(s):

Gustavo Sanchez

Keyword(s):

System Identification ◽

Closed Loop ◽

Process Variable ◽

Loop System ◽

Closed Loop Control ◽

Closed Loop System ◽

Trade Off ◽

Loop Control ◽

Control Loops ◽

Variable Energy

<div>A method to assess the performance of closed loop control loops, based on closed-loop system identification. This method allows to take into account the trade-off between process variable and manipulated variable energy, thus overcoming one of the most important criticisms to Harris' index. </div>

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An optimal closed-loop control strategy for mechanical chest compression devices: A trade-off between the risk of chest injury and the benefit of enhanced blood flow

Computer Methods and Programs in Biomedicine ◽

10.1016/j.cmpb.2012.04.009 ◽

2012 ◽

Vol 108 (1) ◽

pp. 288-298 ◽

Cited By ~ 4

Author(s):

Guang Zhang ◽

Jie-Wen Zheng ◽

Jian Wu ◽

Tai-Hu Wu

Keyword(s):

Blood Flow ◽

Chest Compression ◽

Control Strategy ◽

Closed Loop ◽

Chest Injury ◽

Closed Loop Control ◽

Trade Off ◽

Loop Control ◽

Mechanical Chest Compression

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Closed-loop control of bevel-tip needles based on path planning

Robotica ◽

10.1017/s0263574718000772 ◽

2018 ◽

Vol 36 (12) ◽

pp. 1857-1873

Author(s):

Benyan Huo ◽

Xingang Zhao ◽

Jianda Han ◽

Weiliang Xu

Keyword(s):

Path Planning ◽

Path Length ◽

Optimization Problem ◽

Closed Loop ◽

Control Method ◽

Kinematic Model ◽

Planning Method ◽

Closed Loop Control ◽

Loop Control ◽

Multi Objective

SUMMARYBevel-tip needles have the potential to improve paracentetic precision and decrease paracentetic traumas. In order to drive bevel-tip needles precisely with the constrains of path length and path dangerousness, we propose a closed-loop control method that only requires the position of the needle tip and can be easily applied in a clinical setting. The control method is based on the path planning method proposed in this paper. To establish the closed-loop control method, a kinematic model of bevel-tip needles is first presented, and the relationship between the puncture path and controlled variables is established. Second, we transform the path planning method into a multi-objective optimization problem, which takes the path error, path length and path dangerousness into account. Multi-objective particle swarm optimization is employed to solve the optimization problem. Then, a control method based on path planning is presented. The current needle tip attitude is essential to plan an insertion path. We analyze two methods to obtain the tip attitude and compare their effects using both simulations and experiments. In the end, simulations and experiments in phantom tissue are executed and analyzed, the results show that our methods have high accuracy and have the ability to deal with the model parameter uncertainty.

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The Impact of Visual Feedback Type on the Mastery of Visuo-Motor Transformations

Zeitschrift für Psychologie ◽

10.1027/2151-2604/a000084 ◽

2012 ◽

Vol 220 (1) ◽

pp. 3-9 ◽

Cited By ~ 4

Author(s):

Sandra Sülzenbrück

Keyword(s):

Empirical Research ◽

Visual Feedback ◽

Closed Loop ◽

Motor Planning ◽

Visual Input ◽

Closed Loop Control ◽

Loop Control ◽

Feedback Type ◽

Effective Use ◽

The Impact

For the effective use of modern tools, the inherent visuo-motor transformation needs to be mastered. The successful adjustment to and learning of these transformations crucially depends on practice conditions, particularly on the type of visual feedback during practice. Here, a review about empirical research exploring the influence of continuous and terminal visual feedback during practice on the mastery of visuo-motor transformations is provided. Two studies investigating the impact of the type of visual feedback on either direction-dependent visuo-motor gains or the complex visuo-motor transformation of a virtual two-sided lever are presented in more detail. The findings of these studies indicate that the continuous availability of visual feedback supports performance when closed-loop control is possible, but impairs performance when visual input is no longer available. Different approaches to explain these performance differences due to the type of visual feedback during practice are considered. For example, these differences could reflect a process of re-optimization of motor planning in a novel environment or represent effects of the specificity of practice. Furthermore, differences in the allocation of attention during movements with terminal and continuous visual feedback could account for the observed differences.

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