scholarly journals Twisted string actuation with position feedback for robotic endoscopy

2021 ◽  
Vol 7 (2) ◽  
pp. 343-346
Author(s):  
Davina Schlesiger ◽  
Giuliano A. Giacoppo ◽  
Max B. Schäfer ◽  
Peter P. Pott
Keyword(s):  
Closed Loop ◽  
Position Control ◽  
Low Cost ◽  
Longitudinal Axis ◽  
Displacement Sensor ◽  
Elastic Behaviour ◽  
Position Feedback ◽  
Twisted String

Abstract A twisted string actuator (TSA) is a small, strong, lightweight, and low-cost gear, transforming rotation into a linear pulling movement. The TSA consists of two or more strings that are twisted along their common longitudinal axis. The helix formed in this process becomes shorter the further the bundle is twisted. A possible application is a tendon-based endoscopic robot. To control the movement of the endoscope, a precise contraction of the tendon is necessary. Since the strings of the TSA show an elastic behaviour, position feedback is needed to determine the exact movement of the TSA. In this paper, a TSA with a closed-loop position control by a low-cost displacement sensor is presented.

The Study of Hydraulic Valve Position Control Based on PLC Controller

2014 ◽  
Vol 651-653 ◽  
pp. 928-931
Author(s):  
Chun You Zhang ◽  
Cong Rui Wang
Keyword(s):  
Control System ◽  
Automatic Control ◽  
Closed Loop ◽  
Position Control ◽  
Angular Displacement ◽  
Hydraulic Drive ◽  
Displacement Sensor ◽  
Prototype Model ◽  
Valve Position ◽  
Hydraulic Valve

With the growing shortage of water today, in order to control the flow of pipe conveyance, it is essential for further study of automatic control valves, especially the automatic control technology of control valve. In this paper, by using programmable control and signal transmission technologies etc. a prototype model of hydraulic valve position control is constructed. Prototype model is designed as the closed-loop of position control system, by using high-precision angular displacement sensor detecting the position of the valve plate, converting the output signal of sensor into an industrial process signal 4-20mA with the low-drift transmitter chip XTR101, and with modular PLC as system control center, using three-phase inverter controlling the steering and speed of motor and cooperating with closed pump control system for hydraulic drive, it achieves the closed-loop control hydraulic valve position. This paper provides some technical support for the better use of water resources.

Plastic Optical Fiber Displacement Sensor for Cracks Monitoring

2007 ◽  
Vol 347 ◽  
pp. 487-492 ◽  
Author(s):  
Massimo Olivero ◽  
Guido Perrone ◽  
Alberto Vallan ◽  
Silvio Abrate
Keyword(s):  
Optical Fibers ◽  
Closed Loop ◽  
Low Cost ◽  
Control Unit ◽  
Displacement Sensor ◽  
Axial Distance ◽  
Light Modulation ◽  
Large Core ◽  
Detection Scheme ◽  
Polymer Optical Fibers

In the following we present a low-cost optical system for cracks evolution monitoring. The transducer principle is based on the variation of light transmitted between two facing fibers with their axial distance, exploiting the unique light-collecting capabilities of large-core polymer optical fibers. The characterization shows that the working range of the transducer is up to 3.5cm, with a resolution of 10$m and a repeatability of 5$m. With our current custom-developed control unit, up to four transducers can be arranged to provide a multi-axial displacement sensor or to simultaneously monitor four points for distributed sensing. A closed-loop light modulation/detection scheme is implemented to reduce the environmental noise sensitivity. The control unit is interfaced to a PC via USB port or via GSM/GPRS modem to automatically send periodical reports of the measurements and to issue warnings in case of displacements above a given threshold. Extensive tests in an environmental chamber have been carried out in order to extract calibration curves and to compensate for day-night and summer-winter temperature fluctuations.

Design of Stepping Motor Position Closed Loop Control System Based on PLC

2011 ◽  
Vol 127 ◽  
pp. 126-129
Author(s):  
Li Hong Wang ◽  
Yue Ling Zhao
Keyword(s):  
Control System ◽  
High Speed ◽  
Closed Loop ◽  
Position Control ◽  
Displacement Sensor ◽  
Closed Loop Control ◽  
Stepping Motor ◽  
Loop Control ◽  
Closed Loop Control System ◽  
Loop Control System

A stepping motor position closed loop control system was designed, which adopts displacement sensor to examine the position of the load. The system’s hardware constitute was given here, and the pulse control project was given at the same time. It uses the high-speed pulse output of PLC to export the adjustable frequency pulse. The adjustment of the frequency based on the error of initial value and actual value. On one hand, it can realize fast and accurate position control. On the other hand, it can overcome the weakness of losing step. Thus makes the system have better control function.

scholarly journals Double Closed-Loop Compound Control Strategy for Magnetic Liquid Double Suspension Bearing

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1195
Author(s):  
Jianhua Zhao ◽  
Yongqiang Wang ◽  
Xuchao Ma ◽  
Sheng Li ◽  
Dianrong Gao ◽  
...  
Keyword(s):  
Control Strategy ◽  
Electromagnetic Force ◽  
Closed Loop ◽  
Static Characteristic ◽  
Magnetic Liquid ◽  
Initial Current ◽  
Electromagnetic System ◽  
Initial Flow ◽  
Hydrostatic Force ◽  
Position Feedback

As a new type of suspension bearing, the magnetic liquid double suspension bearing (MLDSB) is mainly supported by electromagnetic suspension and supplemented by hydrostatic support. At present, the MLDSB adopts the regulation strategy of “electromagnetic-position feedback closed-loop, hydrostatic constant-flow supply” (referred to as CFC mode). In the equilibrium position, the external load is carried by the electromagnetic system, and the hydrostatic system produces no supporting force. Thus, the carrying capacity and supporting stiffness of the MLDSB can be reduced. To solve this problem, the double closed-loop control strategy of “electromagnetic system-force feedback inner loop and hydrostatic-position feedback outer loop” (referred to as DCL mode) was proposed to improve the bearing performance and operation stability of the MLDSB. First, the mathematical models of CFC mode and DCL mode of the single DOF supporting system were established. Second, the real-time variation laws of rotor displacement, flow/hydrostatic force, and regulating current/electromagnetic force in the two control modes were plotted, compared, and analyzed. Finally, the influence law of initial current, flow, and controller parameters on the dynamic and static characteristic index were analyzed in detail. The results show that compared with that in CFC mode, the displacement in DCL mode is smaller, and the adjustment time is shorter. The hydrostatic force is equal to the electromagnetic force in DCL mode when the rotor returns to the balance position. Moreover, the system in DCL mode has better robustness, and the initial flow has a more obvious influence on the dynamic and static characteristic indexes. This study provides a theoretical basis for stable suspension control and the safe and reliable operation of the MLDSB.

scholarly journals A Nonlinear Magnetic Stabilization Control Design for an Externally Manipulated DC Motor: An Academic Low-Cost Experimental Platform

Machines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 101
Author(s):  
Leonardo Acho
Keyword(s):  
Hall Effect ◽  
Position Control ◽  
Low Cost ◽  
Time Derivative ◽  
Control Design ◽  
Dc Motor ◽  
Flexible Beam ◽  
Experimental Platform ◽  
Hall Effect Sensor ◽  
Vibrational Control

The main objective of this paper is to present a position control design to a DC-motor, where the set-point is externally supplied. The controller is conceived by using vibrational control theory and implemented by just processing the time derivative of a Hall-effect sensor signal. Vibrational control is robust against model uncertainties. Hence, for control design, a simple mathematical model of a DC-Motor is invoked. Then, this controller is realized by utilizing analog electronics via operational amplifiers. In the experimental set-up, one extreme of a flexible beam attached to the motor shaft, and with a permanent magnet fixed on the other end, is constructed. Therefore, the control action consists of externally manipulating the flexible beam rotational position by driving a moveable Hall-effect sensor that is located facing the magnet. The experimental platform results in a low-priced device and is useful for teaching control and electronic topics. Experimental results are evidenced to support the main paper contribution.

Fast four-channel fibre-optic displacement sensor for measuring impact waves at low cost

2006 ◽  
Vol 17 (5) ◽  
pp. 1162-1166 ◽  
Author(s):  
Bruno Nilsson ◽  
Dan Tilert ◽  
Attila Temun ◽  
Torgny E Carlsson ◽  
Lars Mattsson
Keyword(s):  
Low Cost ◽  
Displacement Sensor ◽  
Fibre Optic

Space Station Environmental, Thermal Control and Life Support (ETCLS): “Meeting the Evolutionary Growth Challenge”

1984 ◽  
Vol 106 (4) ◽  
pp. 287-291
Author(s):  
H. F. Brose
Keyword(s):  
Closed Loop ◽  
Life Support ◽  
Technology Development ◽  
Low Cost ◽  
Space Station ◽  
Thermal Control ◽  
Development Effort ◽  
Program Cost ◽  
Preparedness Plan ◽  
Evolutionary Growth

Renewed interest and planning for a Space Station, probably NASA’s next major space activity, poses a new challenge for ETCLS technology not previously emphasized. Over the past two decades, regenerative life support technology development for Space Station has been underway. This development effort was always aimed at regenerative (closed loop) life support for a full capability Space Station. The level of priority for manned space presence and current budgetary pressures dictate the need for a low cost profile program with an evolutionary growth Space Station. The initial capability may be a small station with a crew of 2 or 3. This station could grow in size and capability by the addition of modules to a station with a crew of 8 to 12 with the possibility of multiple stations in orbit. Depending upon the selected missions, the early station may be best served by an open or only partially closed loop ETCLS whereas the final station may need a completely closed loop ETCLS. The challenge would be to grow in-orbit the ETCLS system capability in a “no-throw-away” fashion in order to minimize annual and total program cost. This paper discusses a possible ETCLS system evolutionary growth scenario, the Space Station architecture variations influencing the ETCLS system design, and a technology preparedness plan for Space Station ETCLS.

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 PERFORMANCE ASSESSMENT OF INTEGRATED SENSOR ORIENTATION WITH A LOW-COST GNSS RECEIVER

2017 ◽  
Vol IV-2/W3 ◽  
pp. 75-80 ◽  
Author(s):  
M. Rehak ◽  
J. Skaloud
Keyword(s):  
Position Control ◽  
Low Cost ◽  
Satellite System ◽  
Bundle Adjustment ◽  
Single Frequency ◽  
Reference Trajectory ◽  
Integrated Sensor ◽  
Homogeneous Surface ◽  
Gnss Receiver ◽  
Sensor Orientation

Mapping with Micro Aerial Vehicles (MAVs whose weight does not exceed 5&amp;thinsp;kg) is gaining importance in applications such as corridor mapping, road and pipeline inspections, or mapping of large areas with homogeneous surface structure, e.g. forest or agricultural fields. In these challenging scenarios, integrated sensor orientation (ISO) improves effectiveness and accuracy. Furthermore, in block geometry configurations, this mode of operation allows mapping without ground control points (GCPs). Accurate camera positions are traditionally determined by carrier-phase GNSS (Global Navigation Satellite System) positioning. However, such mode of positioning has strong requirements on receiver’s and antenna’s performance. In this article, we present a mapping project in which we employ a single-frequency, low-cost (<&amp;thinsp;$100) GNSS receiver on a MAV. The performance of the low-cost receiver is assessed by comparing its trajectory with a reference trajectory obtained by a survey-grade, multi-frequency GNSS receiver. In addition, the camera positions derived from these two trajectories are used as observations in bundle adjustment (BA) projects and mapping accuracy is evaluated at check points (ChP). Several BA scenarios are considered with absolute and relative aerial position control. Additionally, the presented experiments show the possibility of BA to determine a camera-antenna spatial offset, so-called lever-arm.

scholarly journals A Quadruped Robot with the Wooden Body for Static Locomotion in a Controlled Environment

2020 ◽  
Author(s):  
Muhammad Bilal Khan
Keyword(s):  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Position Control ◽  
Low Cost ◽  
Control Design ◽  
Quadruped Robot ◽  
Legged Robots ◽  
Controlled Environment ◽  
Robot Design ◽  
Classroom Setting

We present the design and overall development of an eight degrees of freedom (DOF) based Bioinspired Quadruped Robot (BiQR). The robot is designed with a skeleton made of cedar wood. The wooden skeleton is based on exploring the potential of cedar wood to be a choice for legged robots&rsquo; design. With a total weight of 1.19 kg, the robot uses eight servo motors that run the position control. Relying on the inverse kinematics, the control design enables the robot to perform the walk gait-based locomotion in a controlled environment. The robot has two main aspects: 1) the initial wooden skeleton development of the robot showing it to be an acceptable choice for robot design, 2) the robot&rsquo;s applicability as a low-cost legged platform to test the locomotion in a laboratory or a classroom setting.

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