A Low-Cost Soft Coiled Sensor for Soft Robots

2016 ◽  
Author(s):  
Jianguo Zhao ◽  
Ali Abbas
Keyword(s):  
Optical Fibers ◽  
Closed Loop ◽  
Low Cost ◽  
Soft Materials ◽  
Soft Sensor ◽  
Soft Sensors ◽  
Soft Robots ◽  
Conductive Liquid ◽  
Loop Control ◽  
Sewing Threads

Soft robots made from soft materials can closely emulate biological system using simple soft mechanical structures. Compared with traditional rigid-link robots, they are safe to work with humans and can adapt to confined environments. As a result, they are widely used for various robotic locomotions and manipulations. Nevertheless, for soft robots, being able to sense its state to enable closed-loop control using soft sensors remains a challenge. Existing sensors include external sensors such as camera systems, electromagnetic tracking systems, and internal sensors such as optical fibers, conductive liquid, and carbon black filled strips. In this paper, we investigate a new soft sensor made from low-cost conductive nylon sewing threads. By continuously inserting twists into a thread under some weight, coils can be formed to enable a coiled soft sensor. The resistance of the sensor varies with the change of length. The fabrication and experiments for this new coiled sensor is described in this paper. Embedding this sensor to a 3D printed soft manipulator demonstrates the sensing capability. Compared to existing soft sensors, the coiled sensor is low-cost, easy to fabricate, and can also be used as an actuator. It can be embedded to any soft robot to measure the deformation for closed-loop feedback control.

scholarly journals Accurate Motion Control of a Pneumatic Linear Peristaltic Actuator

Actuators ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 63 ◽  
Author(s):  
João Falcão Carneiro ◽  
João Bravo Pinto ◽  
Fernando Gomes de Almeida
Keyword(s):  
Closed Loop ◽  
Low Cost ◽  
Dynamic Performance ◽  
Control Law ◽  
Control Loop ◽  
Control Laws ◽  
Loop Control ◽  
Error Band ◽  
Short Service Life ◽  
High Mechanical Stress

Pneumatic linear peristaltic actuators can offer some potential advantages when compared with conventional ones. The low cost, virtually unlimited stroke and easy implementation of curved motion profiles are among those benefits. On the downside, these actuators suffer high mechanical stress that can lead to short service life and increased leakage among chambers during the actuator lifetime. One way to cope with this problem is to impose the force—instead of the displacement—between rollers, as this has been shown to improve the endurance of the hose while reducing leakage during the actuator lifetime. This paper presents closed control loop results using such a setup. Previous studies with linear peristaltic actuators have revealed that, although it is possible to reach zero steady state error to constant references with closed loop control, the dynamic response obtained is very slow. This paper is mainly focused on this topic, namely on the development of several control laws to improve the dynamic performance of the system while avoiding limit cycles. The new developed control law leads to an average time of 1.67 s to reach a 0.1 mm error band in an experiment consisting of a series of 16 steps ranging from 0.02 to 0.32 m in amplitude.

scholarly journals Real-Time Low-Cost Speed Monitoring and Control of Three-Phase Induction Motor via a Voltage/Frequency Control Approach

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Ali Hmidet ◽  
Olfa Boubaker
Keyword(s):  
Real Time ◽  
Induction Motor ◽  
Closed Loop ◽  
Low Cost ◽  
Closed Loop Control ◽  
Loop Control ◽  
Control Approach ◽  
Three Phase ◽  
Wide Range ◽  
Voltage Frequency

In this paper, a new design of a real-time low-cost speed monitoring and closed-loop control of the three-phase induction motor (IM) is proposed. The proposed solution is based on a voltage/frequency (V/F) control approach and a PI antiwindup regulator. It uses the Waijung Blockset which considerably alleviates the heaviness and the difficulty of the microcontroller’s programming task incessantly crucial for the implementation and the management of such complex applications. Indeed, it automatically generates C codes for many types of microcontrollers like the STM32F4 family, also used in this application. Furthermore, it offers a cost-effective design reducing the system components and increasing its efficiency. To prove the efficiency of the suggested design, not only simulation results are carried out for a wide range of variations in load and reference speed but also experimental assessment. The real-time closed-loop control performances are proved using the aMG SQLite Data Server via the UART port board, whereas Waijung WebPage Designer (W2D) is used for the web monitoring task. Experimental results prove the accuracy and robustness of the proposed solution.

The Application of PLC in the Stepper Motor Closed-Loop Control System Design

2012 ◽  
Vol 605-607 ◽  
pp. 1537-1540 ◽  
Author(s):  
Xiao Yu Wang
Keyword(s):  
Control System ◽  
Closed Loop ◽  
Low Cost ◽  
Stepper Motor ◽  
Closed Loop Control ◽  
Loop Control ◽  
Closed Loop Control System ◽  
System Flow ◽  
Loop Control System

The application of PLC 、Stepper motor driver and Encoder are introduced in stepper motor closed-loop control system. The Principle diagram is analyzed, the Control System flow chart and Software program are designed. Through in-situ operation, the system has been proved well reliability、 stability and simplicity , achieved high accuracy and low cost requirements。

scholarly journals Exploiting short-term memory in soft body dynamics as a computational resource

2014 ◽  
Vol 11 (100) ◽  
pp. 20140437 ◽  
Author(s):  
K. Nakajima ◽  
T. Li ◽  
H. Hauser ◽  
R. Pfeifer
Keyword(s):  
Degrees Of Freedom ◽  
Closed Loop ◽  
Short Term Memory ◽  
Soft Materials ◽  
Computational Resource ◽  
Soft Body ◽  
Short Term ◽  
Term Memory ◽  
Loop Control ◽  
Body Dynamics

Soft materials are not only highly deformable, but they also possess rich and diverse body dynamics. Soft body dynamics exhibit a variety of properties, including nonlinearity, elasticity and potentially infinitely many degrees of freedom. Here, we demonstrate that such soft body dynamics can be employed to conduct certain types of computation. Using body dynamics generated from a soft silicone arm, we show that they can be exploited to emulate functions that require memory and to embed robust closed-loop control into the arm. Our results suggest that soft body dynamics have a short-term memory and can serve as a computational resource. This finding paves the way towards exploiting passive body dynamics for control of a large class of underactuated systems.

scholarly journals A soft matter computer for soft robots

2019 ◽  
Vol 4 (33) ◽  
pp. eaaw6060 ◽  
Author(s):  
M. Garrad ◽  
G. Soter ◽  
A. T. Conn ◽  
H. Hauser ◽  
J. Rossiter
Keyword(s):  
Smart Materials ◽  
Soft Matter ◽  
Autonomous Robots ◽  
Low Cost ◽  
Input Parameter ◽  
Soft Materials ◽  
Soft Robots ◽  
Stimulus Response ◽  
Bending Actuator ◽  
Two Degree Of Freedom

Despite the growing interest in soft robotics, little attention has been paid to the development of soft matter computational mechanisms. Embedding computation directly into soft materials is not only necessary for the next generation of fully soft robots but also for smart materials to move beyond stimulus-response relationships and toward the intelligent behaviors seen in biological systems. This article describes soft matter computers (SMCs), low-cost, and easily fabricated computational mechanisms for soft robots. The building block of an SMC is a conductive fluid receptor (CFR), which maps a fluidic input signal to an electrical output signal via electrodes embedded into a soft tube. SMCs could perform both analog and digital computation. The potential of SMCs is demonstrated by integrating them into three soft robots: (i) a Softworm robot was controlled by an SMC that generated the control signals necessary for three distinct gaits; (ii) a soft gripper was given a set of reflexes that could be programmed by adjusting the parameters of the CFR; and (iii) a two–degree of freedom bending actuator was switched between three distinct behaviors by varying only one input parameter. SMCs are a low-cost way to integrate computation directly into soft materials and an important step toward entirely soft autonomous robots.

New Electromagnetic Design of Miniature AF VCM Actuator with Low Cost

2015 ◽  
Vol 32 (4) ◽  
pp. 421-426 ◽  
Author(s):  
C.-S. Liu ◽  
L. Kuo ◽  
B.-J. Tsai
Keyword(s):  
High Performance ◽  
Closed Loop ◽  
Cell Phones ◽  
Low Cost ◽  
Voice Coil Motor ◽  
Open Loop ◽  
Closed Loop Control ◽  
Electromagnetic Design ◽  
Loop Control ◽  
Auto Focusing

AbstractRecently, compact and high-resolution camera modules with auto-focusing (AF) function have been integrated into cell phones in order to capture sharp photographs. Consumer demands AF camera modules in cell phones to have high performance with low cost. Accordingly, the present study proposes a new electromagnetic design of miniature AF voice coil motor (VCM) actuator with closed-loop control for cell phone camera modules to satisfy the requirements. The structure of the proposed AF VCM actuators was designed by using simulation methods. The performance of the proposed AF VCM actuators was demonstrated by a laboratory-built prototype. The experimental results have shown that the proposed AF VCM actuator has excellent performance with lower power consumption, higher positioning repeatability, and lower cost, when compared to previous AF VCM actuators with open-loop control or closed-loop control.

scholarly journals Al Microheater and Ni Temperature Sensor Set based-on Photolithography with Closed-Loop Control

2015 ◽  
Vol 5 (4) ◽  
pp. 849
Author(s):  
Pittaya Deekla ◽  
Rungrueang Phatthanakun ◽  
Sarawut Sujitjorn ◽  
Nimit Chomnawang
Keyword(s):  
Temperature Sensor ◽  
Closed Loop ◽  
Low Cost ◽  
Pi Controller ◽  
Closed Loop Control ◽  
Micro Electro Mechanical Systems ◽  
Loop Control ◽  
Loop Feedback ◽  
Closed Loop Feedback ◽  
Lift Off

This article proposes the development of a new low-cost microheater and temperature sensor set. It was developed based on Micro-Electro-Mechanical Systems (MEMS) which based on photolithography technique and lift-off technique. Thin film of aluminum was utilized as microheater and encompassed nickel temperature sensor inside in order to decrease response time of the desired temperature. To control the various temperatures correctly, closed-loop feedback control based on PI-controller was adapted into control circuit system. Microcontroller was implemented to control and observe the responses of temperature between 40°C and 120°C. Simulation and experimental results are also presented.

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.

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