Analysis of Barriers to Control of Manipulators Within Accessible Output Sets

1995 ◽  
Author(s):  
Edward J. Haug ◽  
Frederick A. Adkins ◽  
Chaoxin Charles Qiu ◽  
Jeng Yen
Keyword(s):  
Quadratic Forms ◽  
Closed Loop ◽  
Position Control ◽  
Quantitative Information ◽  
Second Order ◽  
Velocity Control ◽  
Unilateral Constraints ◽  
Open Chain ◽  
Output Control ◽  
Curves And Surfaces

Abstract Barriers to output control of manipulators, both in the interior and at the boundary of accessible output sets, are analyzed using first and second order Taylor approximations of the output in selected directions as functions of manipulator input. The formulation is valid for both planar and spatial manipulators, with open chain and closed loop structures, and accounts for the effects of unilateral constraints on the range of admissible control inputs. Criteria defining curves and surfaces associated with singular output control of manipulators are extended to define normals to such curves and surfaces. It is shown that output velocity in the direction normal to such curves and surfaces must be zero, so they arc barriers to velocity control in the associated manipulator configuration. Second order Taylor expansion of normal output with respect to input parameters yields quantitative information regarding barriers to output position control. Definiteness properties of the resulting quadratic approximation define directions of admissible and inadmissible outputs. Algorithms for automatically computing the associated quadratic forms and eigenvalues that determine their definiteness properties are presented and illustrated using planar examples.

Plans and The Structure of Target Acquisition Behavior

1981 ◽  
Vol 25 (1) ◽  
pp. 571-575
Author(s):  
R. A. Miller ◽  
R. J. Jagacinski ◽  
R. B. Nalavade ◽  
W. W. Johnson
Keyword(s):  
Closed Loop ◽  
Position Control ◽  
Open Loop ◽  
General Strategy ◽  
Velocity Control ◽  
Additional Time ◽  
First Order ◽  
Oscilloscope Screen ◽  
Activity Sequence ◽  
Event Based

Subjects manipulated a position control stick with one hand and a velocity control stick with the other hand in order to capture a moving target displayed on an oscilloscope screen. The two control sticks were additively coupled. In order to understand the coordination of the two control sticks, event-based first-order markov “activity sequence generators” were constructed for individual subjects. These discrete probabilistic structures are closely related to each subject's overall plan or general strategy for the capture task. Striking individual differences and strategic errors in performance were revealed. When combined with additional time-conditioned (open-loop) and error-conditioned (closed-loop) details, the activity sequence generators provide a basis for a hierarchic description of this perceptual-motor skill.

Experimental investigation and propulsion control for a bio-inspired robotic undulatory fin

Robotica ◽  
2015 ◽  
Vol 33 (5) ◽  
pp. 1062-1084 ◽  
Author(s):  
Michael Sfakiotakis ◽  
John Fasoulas ◽  
Manolis M. Kavoussanos ◽  
Manolis Arapis
Keyword(s):  
Closed Loop ◽  
Position Control ◽  
Control Strategies ◽  
Underwater Vehicles ◽  
Open Loop ◽  
Water Tank ◽  
Velocity Control ◽  
Wave Kinematics ◽  
Propulsion Control ◽  
Simultaneous Adjustment

SUMMARYUndulatory fin propulsion, inspired by the locomotion of aquatic species such as electric eels and cuttlefish, holds considerable potential for endowing underwater vehicles with enhanced propulsion and maneuvering abilities, to address the needs of a growing number of applications. However, there are still gaps in our understanding of the effect of the fin undulations' characteristics on the generated thrust, particularly within the context of developing propulsion control strategies for such robotic systems. Towards this end, we present the design and experimental evaluation of a robotic fin prototype, comprised of eight individually-actuated fin rays. An artificial central pattern generator (CPG) is used to produce the rays' undulatory motion pattern. Experiments are performed inside a water tank, with the robotic fin suspended from a carriage, whose motion is constrained via a linear guide. The results from a series of detailed parametric investigations reveal several important findings regarding the effect of the undulatory wave kinematics on the propulsion speed and efficiency. Based on these findings, two alternative strategies for propulsion control of the robotic fin are proposed. In the first one, the speed is varied through changes in the undulation amplitude, while the second one involves simultaneous adjustment of the undulation frequency and number of waves. These two strategies are evaluated via experiments demonstrating open-loop velocity control, as well as closed-loop position control of the prototype.

Closed-loop control of a prosthetic finger via evoked proprioceptive information

2021 ◽  
Author(s):  
Luis Vargas ◽  
He (Helen) Huang ◽  
Yong Zhu ◽  
Xiaogang Hu
Keyword(s):  
Closed Loop ◽  
Position Control ◽  
Sensory Information ◽  
Proprioceptive Feedback ◽  
Closed Loop Control ◽  
Proprioceptive Information ◽  
Continuous Control ◽  
Velocity Control ◽  
Loop Control ◽  
Prosthetic Finger

Abstract Objective. Proprioceptive information plays an important role for recognizing and coordinating our limb’s static and dynamic states relative to our body or the environment. In this study, we determined how artificially evoked proprioceptive feedback affected the continuous control of a prosthetic finger. Approach. We elicited proprioceptive information regarding the joint static position and dynamic movement of a prosthetic finger via a vibrotactor array placed around the subject’s upper arm. Myoelectric signals of the finger flexor and extensor muscles were used to control the prosthesis, with or without the evoked proprioceptive feedback. Two control modes were evaluated: the myoelectric signal amplitudes were continuously mapped to either the position or the velocity of the prosthetic joint. Main Results. Our results showed that the evoked proprioceptive information improved the control accuracy of the joint angle, with comparable performance in the position- and velocity-control conditions. However, greater angle variability was prominent during position-control than velocity-control. Without the proprioceptive feedback, the position-control tended to show a smaller angle error than the velocity-control condition. Significance. Our findings suggest that closed-loop control of a prosthetic device can potentially be achieved using non-invasive evoked proprioceptive feedback delivered to intact participants. Moreover, the evoked sensory information was integrated during myoelectric control effectively for both control strategies. The outcomes can facilitate our understanding of the sensorimotor integration process during human-machine interactions, which can potentially promote fine control of prosthetic hands.

Analysis of Reset Control Systems Consisting of a FORE and Second-Order Loop1

2001 ◽  
Vol 123 (2) ◽  
pp. 279-283 ◽  
Author(s):  
Qian Chen ◽  
Yossi Chait ◽  
C. V. Hollot
Keyword(s):  
Control Systems ◽  
Closed Loop ◽  
Second Order ◽  
Step Response ◽  
Steady State Response ◽  
First Order ◽  
State Response ◽  
Loop Transfer Function ◽  
Performance Specifications ◽  
Reset Control

Reset controllers consist of two parts—a linear compensator and a reset element. The linear compensator is designed, in the usual ways, to meet all closed-loop performance specifications while relaxing the overshoot constraint. Then, the reset element is chosen to meet this remaining step-response specification. In this paper, we consider the case when such linear compensation results in a second-order (loop) transfer function and where a first-order reset element (FORE) is employed. We analyze the closed-loop reset control system addressing performance issues such as stability, steady-state response, and transient performance.

Design of Salt In-Bags Incasing Control Management System Based on Dual Closed-Loop Fuzzy Controller

2014 ◽  
Vol 596 ◽  
pp. 620-624
Author(s):  
Yan Bo Hui ◽  
Yong Gang Wang ◽  
Li Wang ◽  
Qun Feng Niu
Keyword(s):  
Management System ◽  
Closed Loop ◽  
Position Control ◽  
Product Information ◽  
Fuzzy Controller ◽  
High Reliability ◽  
Logistics Management ◽  
High Control ◽  
Control Management System ◽  
Control Management

According to auto-incasing equipment characteristic and control demand, a kind of salt in-bags incasing control management system was designed. The paper introduced the key technologies realization of the system. In the paper, a new fuzzy controller was designed to build a dual closed-loop fuzzy control system, realizing incasing goal site error on-line continuous correction. A logistics management module based on e-Tag was designed to realize product information traceable management. The experimental results show the system realizes accurate position control and RFID logistics management with high reliability and high control precision. The system can be popularized to other products packaging industry.

scholarly journals Nuclear Response to Second-Order Isospin Probes in Connection to Double Beta Decay

Universe ◽  
2020 ◽  
Vol 6 (11) ◽  
pp. 217
Author(s):  
Francesco Cappuzzello ◽  
Manuela Cavallaro
Keyword(s):  
Charge Exchange ◽  
Theoretical Calculations ◽  
Nuclear Matrix Element ◽  
Quantitative Information ◽  
Mass Scale ◽  
Second Order ◽  
Double Beta Decay ◽  
Coupling Constants ◽  
Exchange Reactions ◽  
Double Charge

One of the key ingredients needed to extract quantitative information on neutrino absolute mass scale from the possible measurement of the neutrinoless double-beta (0νββ) decay half-lives is the nuclear matrix element (NME) characterizing such transitions. NMEs are not physical observables and can only be deduced by theoretical calculations. However, since the atomic nuclei involved in the decay are many-body systems, only approximated values are available to date. In addition, the value of the coupling constants to be used for the weak interaction vertices is still an open question, which introduces a further indetermination in the calculations of NMEs. Several experimental approaches were developed in the years with the aim of providing useful information to further constrain the theory. Here we give an overview of the role of charge exchange reactions in this scenario, focusing on second-order processes, namely the double charge exchange (DCE) reactions.

Sign in / Sign up

Export Citation Format

Share Document