scholarly journals Development of a 3-PRR Precision Tracking System with Full Closed-Loop Measurement and Control

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1756 ◽  
Author(s):  
Ling-bo Xie ◽  
Zhi-cheng Qiu ◽  
Xian-min Zhang
Keyword(s):  
Feedback Control ◽  
Closed Loop ◽  
Tracking System ◽  
Network Control ◽  
Closed Loop Control ◽  
Loop Control ◽  
Feed Forward Control ◽  
Displacement Sensors ◽  
Precision Tracking ◽  
Parallel Platform

A 3-PRR (three links with each link consisting of a prismatic pair and two rotating pairs) parallel platform was designed for application in a vacuum environment. To meet the requirement of high tracking accuracy of the 3-PRR parallel platform, a full closed-loop control precision tracking system with laser displacement sensors and linear grating encoders was analysed and implemented. Equally-spaced laser displacement sensors and linear grating encoders were adopted not only for measurement but also for feedback control. A feed-forward control method was applied for comparison before conducting the closed-loop feedback control experiments. The closed-loop control experiments were conducted by adopting the PI (proportion and integration) feedback control and RBF (radial basis function) neural network control algorithms. The experimental results demonstrate that the feed-forward control, PI feedback control, and RBF neural-network control algorithms all have a better control effect than that of semi-closed-loop control, which proves the validity of the designed full closed-loop control system based on the combination of laser displacement sensors and linear grating encoders.

CLOSED-LOOP CONTROL OF THE THALAMOCORTICAL RELAY NEURON'S PARKINSONIAN STATE BASED ON SLOW VARIABLE

2013 ◽  
Vol 23 (04) ◽  
pp. 1350017 ◽  
Author(s):  
CHEN LIU ◽  
JIANG WANG ◽  
YING-YUAN CHEN ◽  
BIN DENG ◽  
XI-LE WEI ◽  
...  
Keyword(s):  
Feedback Control ◽  
Control Strategy ◽  
Closed Loop ◽  
Slow Variable ◽  
Closed Loop Control ◽  
Fast Variable ◽  
Qualitative And Quantitative Analysis ◽  
Feedback Controllers ◽  
Loop Control ◽  
Qualitative And Quantitative

A novel closed-loop control strategy is proposed to control Parkinsonian state based on a computational model. By modeling thalamocortical relay neurons under external electric field, a slow variable feedback control is applied to restore its relay functionality. Qualitative and quantitative analysis demonstrates the performance of feedback controller based on slow variable is more efficient compared with traditional feedback control based on fast variable. These findings point to the potential value of model-based design of feedback controllers for Parkinson's disease.

On Passive Implementation of Feedback Control Systems

1989 ◽  
Vol 111 (2) ◽  
pp. 339-342
Author(s):  
R. Shoureshi
Keyword(s):  
Feedback Control ◽  
Control Systems ◽  
State Feedback ◽  
Closed Loop ◽  
State Feedback Control ◽  
Closed Loop Control ◽  
Linear Quadratic ◽  
Loop Control ◽  
Feedback Control Systems ◽  
Linear Quadratic Regulators

Closed-loop control systems, especially linear quadratic regulators (LQR), require feedbacks of all states. This requirement may not be feasible for those systems which have limitations due to geometry, power, required sensors, size, and cost. To overcome such requirements a passive method for implementation of state feedback control systems is presented.

Full-gap tracking system for parallel plate electrostatic actuators using closed-loop control

2016 ◽  
Vol 244 ◽  
pp. 174-183 ◽  
Author(s):  
Eurico Esteves Moreira ◽  
Vasco Lima ◽  
Filipe Serra Alves ◽  
Jorge Cabral ◽  
João Gaspar ◽  
...  
Keyword(s):  
Parallel Plate ◽  
Closed Loop ◽  
Tracking System ◽  
Closed Loop Control ◽  
Electrostatic Actuators ◽  
Loop Control

High-bandwidth fine tracking system for optical communication with double closed-loop control method

2019 ◽  
Vol 58 (02) ◽  
pp. 1
Author(s):  
Yukun Wang ◽  
Dayu Li ◽  
Rui Wang ◽  
Chengbin Jin ◽  
Shaoxin Wang ◽  
...  
Keyword(s):  
Optical Communication ◽  
Closed Loop ◽  
Control Method ◽  
Tracking System ◽  
Closed Loop Control ◽  
Loop Control ◽  
High Bandwidth

Self-feedback motion control for cable-driven parallel manipulators

2013 ◽  
Vol 228 (1) ◽  
pp. 77-89 ◽  
Author(s):  
Weihai Chen ◽  
Xiang Cui ◽  
Guilin Yang ◽  
Jingyuan Chen ◽  
Yan Jin
Keyword(s):  
Feedback Control ◽  
Motion Control ◽  
Control Algorithm ◽  
Closed Loop ◽  
Joint Angle ◽  
Time Derivative ◽  
Parallel Manipulators ◽  
The Self ◽  
Closed Loop Control ◽  
Loop Control

This article proposes a closed-loop control scheme based on joint-angle feedback for cable-driven parallel manipulators (CDPMs), which is able to overcome various difficulties resulting from the flexible nature of the driven cables to achieve higher control accuracy. By introducing a unique structure design that accommodates built-in encoders in passive joints, the seven degrees of freedom (7-DOF) CDPM can obtain joint angle values without external sensing devices, and it is used for feedback control together with a proper closed-loop control algorithm. The control algorithm has been derived from the time differential of the kinematic formulation, which relates the joint angular velocities to the time derivative of cable lengths. In addition, the Lyapunov stability theory and Monte Carlo method have been used to mathematically verify the self-feedback control law that has tolerance for parameter errors. With the aid of co-simulation technique, the self-feedback closed-loop control is applied on a 7-DOF CDPM and it shows higher motion accuracy than the one with an open-loop control. The trajectory tracking experiment on the motion control of the 7-DOF CDPM demonstrated a good performance of the self-feedback control method.

Parameter Identification and Closed Loop Control of a Flywheel Mounted Hovering Robot

2017 ◽  
Author(s):  
Akin Tatoglu
Keyword(s):  
Control System ◽  
Feedback Control ◽  
Transient Response ◽  
Closed Loop ◽  
Total Error ◽  
Acceptable Level ◽  
Measurement Unit ◽  
Closed Loop Control ◽  
Loop Control ◽  
Heading Control

A prototype of a hovering multi-terrain mobile robot platform that makes use of a flywheel for stabilization and heading control for rapid maneuverability was developed and presented in a prior paper. It was shown that flywheel stored energy could be transferred to the overall body to generate rapid angular motion once wheel is instantaneously stopped. Solution improved localization accuracy and reduced the overall sensitivity with respect to external disturbances such as non-flat terrain. In this paper, we present a feedback control system to measure dynamic parameters before and after the wheel is stopped. System is designed to follow a predefined path plan and instantaneous torque change causes oscillation after a waypoint is reached. To address this issue, we updated system with an inertial measurement unit (IMU) as a feedback sensor. Then, we investigate the feedback control of individual forward thrust vectors as well as wheel braking timing to minimize amplitude of transient response oscillation and to reduce the steady-state error to an acceptable level that differential drive fans could compensate this error and correct the heading after the rotation around a waypoint occurs. In addition to that, previous mechanical system could transfer all energy stored at once and was not adjustable. In this research, we also investigate varying amount of angular inertia generated by fans and wheel individually and together. To do so, system is modified with stronger forward thrusters. Prior to running the system with a full dynamic model with real mechanism, we implemented a simulation to empirically extract system parameters and adjust controller gains to follow a predefined path with open and closed loop control schemas with objective of minimizing localization error. Finally system is tested with real mechanism. Governing equations, simulation and empirical results comparison are presented and generated trajectories of various simulation and real world settings are listed. Test results verify that, with a closed loop control system, overshoot and total error about a waypoint can be minimized to an acceptable level at and after transient response phase.

Control of the Fabrication of Long Slender Workpieces of Arbitrary Shape—Part II: Closed-Loop Control of the Multi-Axis Bending Process

1996 ◽  
Vol 118 (3) ◽  
pp. 549-556 ◽  
Author(s):  
J. X. Luo ◽  
D. L. Joynt ◽  
K. A. Stelson
Keyword(s):  
Feedback Control ◽  
Laser Scanning ◽  
Closed Loop ◽  
Transfer Functions ◽  
Shape Representation ◽  
Closed Loop Control ◽  
Loop Control ◽  
Bending Process ◽  
Shape Errors ◽  
The Difference

A feedback control scheme for the multi-axis bending process is presented. The closed-loop control is derived from transfer functions that represent the bending and twisting processes. The dynamics of these processes are due to the convection of shape between the bending dies during deformation. The success of the feedback control also depends on accurate measurement of part shape. A method based on laser scanning has been developed to find the intrinsic shape representation of the measured workpiece. Shape errors are defined as the difference between the intrinsic geometric quantities of the actual and desired part. By applying shape errors to the inverse transfer functions, we can obtain incremental changes in the axis control commands. Experimental results demonstrate that the feedback control causes shape errors to decrease on subsequent iterations.

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