scholarly journals Application of the Novint Falcon haptic device as an actuator in real-time control

Author(s):  
Daniel J. Block ◽  
Mark B. Michelotti ◽  
Ramavarapu S. Sreenivas

AbstractThis paper describes the development of an embedded system whose purpose is to control the Novint Falcon as a robot, and to develop a control experiment that demonstrates the use the Novint Falcon as a robotic actuator. The Novint Falcon, which is a PC input device, is “haptic” in the sense that it has a force feedback component. Its relatively low cost compared with other platforms makes it a good candidate for academic application in robot modeling and control. An embedded system is developed to interface with the multiple motors and sensors present in the Novint Falcon, which is subsequently used to control three independent Novint Falcons for a “ballon- plate” experiment. The results show that the device is a viable solution for high-speed actuation of small-scale mechanical systems.

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3405 ◽  
Author(s):  
Manuel Espinosa-Gavira ◽  
Agustín Agüera-Pérez ◽  
Juan González de la Rosa ◽  
José Palomares-Salas ◽  
José Sierra-Fernández

Very short-term solar forecasts are gaining interest for their application on real-time control of photovoltaic systems. These forecasts are intimately related to the cloud motion that produce variations of the irradiance field on scales of seconds and meters, thus particularly impacting in small photovoltaic systems. Very short-term forecast models must be supported by updated information of the local irradiance field, and solar sensor networks are positioning as the more direct way to obtain these data. The development of solar sensor networks adapted to small-scale systems as microgrids is subject to specific requirements: high updating frequency, high density of measurement points and low investment. This paper proposes a wireless sensor network able to provide snapshots of the irradiance field with an updating frequency of 2 Hz. The network comprised 16 motes regularly distributed over an area of 15 m × 15 m (4 motes × 4 motes, minimum intersensor distance of 5 m). The irradiance values were estimated from illuminance measurements acquired by lux-meters in the network motes. The estimated irradiances were validated with measurements of a secondary standard pyranometer obtaining a mean absolute error of 24.4 W/m 2 and a standard deviation of 36.1 W/m 2 . The network was able to capture the cloud motion and the main features of the irradiance field even with the reduced dimensions of the monitoring area. These results and the low-cost of the measurement devices indicate that this concept of solar sensor networks would be appropriate not only for photovoltaic plants in the range of MW, but also for smaller systems such as the ones installed in microgrids.


Author(s):  
Daniel Banks ◽  
Jos van ’t Hoff ◽  
Kenneth Doherty

An Oscillating Wave Surge Converter (OWSC) is a Wave Energy Converter (WEC) that consists of a bottom-hinged flap which oscillates due to wave action. Extensive research has been performed on this type of WEC through small scale experimental wave tank tests. One of the key challenges of experimental testing is replicating the characteristics of the Power Take-Off (PTO) system of the equivalent full scale WEC. Many scale models rely on simplified mechanical designs to simulate a PTO system. This can often restrict the experimental research into the influence of PTO design and control strategies of WECs. In order to model PTO systems and control strategies more accurately other tools are needed. This paper describes the design and build of a PLC controlled Force Feedback Dynamometer (FFD) system that enables the testing of more sophisticated control strategies applicable to an OWSC through fast application of a variable PTO damping torque. A PLC system is shown to be a viable control for PTO strategy investigations through velocity triggered damping levels. Examples of both PTO and position control strategies are presented.


2012 ◽  
Vol 614-615 ◽  
pp. 1562-1565
Author(s):  
Yu Sen Li ◽  
Ying Sun

In order to realize the sensor signal acquisition and analysis of data, according to data acquisition system design ideas of the PCI bus, applying to CPLD complex programmable controller and CH365 interface chip and combined with the actual needs of data collection ,designed a kind of low cost, high speed process controller. CPLD realizes data cache control and the control of reading. This design can gather 16 roads analog signals and real-time pulse signal of 8 roads on the same time, which includes a 16-bit digital output channel and a 32-bit counter, could be used in the real-time control.


Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 317 ◽  
Author(s):  
Raimarius Delgado ◽  
Byoung Choi

This paper proposes a real-time embedded system for joint space control of omnidirectional mobile robots. Actuators driving an omnidirectional mobile robot are connected in a line topology which requires synchronization to move simultaneously in translation and rotation. We employ EtherCAT, a real-time Ethernet network, to control servo controllers for the mobile robot. The first part of this study focuses on the design of a low-cost embedded system utilizing an open-source EtherCAT master. Although satisfying real-time constraints is critical, a desired trajectory on the center of the mobile robot should be decomposed into the joint space to drive the servo controllers. For the center of the robot, a convolution-based path planner and a corresponding joint space control algorithm are presented considering its physical limits. To avoid obstacles that introduce geometric constraints on the curved path, a trajectory generation algorithm considering high curvature turning points is adapted for an omnidirectional mobile robot. Tracking a high curvature path increases mathematical complexity, which requires precise synchronization between the actuators of the mobile robot. An improvement of the distributed clock—the synchronization mechanism of EtherCAT for slaves—is presented and applied to the joint controllers of the mobile robot. The local time of the EtherCAT master is dynamically adjusted according to the drift of the reference slave, which minimizes the synchronization error between each joint. Experiments are conducted on our own developed four-wheeled omnidirectional mobile robot. The experiment results confirm that the proposed system is very effective in real-time control applications for precise motion control of the robot even for tracking high curvature paths.


2020 ◽  
Author(s):  
François Bertaux ◽  
Sebastián Sosa Carrillo ◽  
Achille Fraisse ◽  
Chetan Aditya ◽  
Mariela Furstenheim ◽  
...  

AbstractNew small-scale, low-cost bioreactor designs provide researchers with exquisite control of environmental parameters of microbial cultures over long durations, allowing them to perform sophisticated, high-quality experiments that are particularly useful in systems biology, synthetic biology and bioengineering. However, existing setups are limited in their automated measurement capabilities, primarily because sensitive and specific measurements require bulky, expensive, stand-alone instruments (for example, most single-cell resolved measurements require a cytometer or a microscope). We present here ReacSight, a generic and flexible strategy to enhance multi-bioreactor platforms for automated measurements and reactive experiment control. We use ReacSight to assemble a platform for single-cell resolved characterization and reactive optogenetic control of parallel yeast continuous cultures. We demonstrate its usefulness by achieving parallel real-time control of gene expression with light in different bioreactors and by exploring the relationship between fitness, nutrient scarcity and cellular stress density using highly-controlled and informative competition assays.


2003 ◽  
Vol 98 (1) ◽  
pp. 96-99 ◽  
Author(s):  
Nedal Hejazi ◽  
Alfred Witzmann ◽  
Werner Hassler

Object. Intraoperative cervical epidurography (ICE) was used during anterior cervical procedures to assess the success of bone resection and indicate the need for immediate correction in the event of inadequate decompression. Methods. The adequacy of decompression was assessed by the operating neurosurgeon who performed ICE after anterior microdiscectomy with exposure of the dura mater. If the decompression was deemed inadequate, additional bone was removed using a high-speed drill. Epidurography was conducted after each subsequent decompression until adequate bone removal was achieved. This was undertaken in 39 patients undergoing anterior cervical procedures. Nine patients underwent corpectomy, 21 one-level, and nine two-level discectomy. The ICE revealed insufficient resections requiring additional bone removal in 14 (36%) of the 39 patients. Conclusions. The goal of ICE is to ensure adequate decompression, and if such has not been achieved, to allow for additional immediate bone excision. Furthermore, ICE provides additional real-time control of the position of cages and screws to avoid dural tear or spinal cord compression. Because of this immediate feedback, the success rate of anterior cervical procedures can be improved. The advantages of this modality include real-time assessment, low cost, simplicity, and speed.


2017 ◽  
Vol 28 (10) ◽  
pp. 1750126 ◽  
Author(s):  
Yutong Liu ◽  
Chengxuan Cao ◽  
Yaling Zhou ◽  
Ziyan Feng

In this paper, an improved real-time control model based on the discrete-time method is constructed to control and simulate the movement of high-speed trains on large-scale rail network. The constraints of acceleration and deceleration are introduced in this model, and a more reasonable definition of the minimal headway is also presented. Considering the complicated rail traffic environment in practice, we propose a set of sound operational strategies to excellently control traffic flow on rail network under various conditions. Several simulation experiments with different parameter combinations are conducted to verify the effectiveness of the control simulation method. The experimental results are similar to realistic environment and some characteristics of rail traffic flow are also investigated, especially the impact of stochastic disturbances and the minimal headway on the rail traffic flow on large-scale rail network, which can better assist dispatchers in analysis and decision-making. Meanwhile, experimental results also demonstrate that the proposed control simulation method can be in real-time control of traffic flow for high-speed trains not only on the simple rail line, but also on the complicated large-scale network such as China’s high-speed rail network and serve as a tool of simulating the traffic flow on large-scale rail network to study the characteristics of rail traffic flow.


Author(s):  
Akashdeep Bhardwaj

This article describes how the rise of fog computing to improve cloud computing performance and the acceptance of smart devices is slowly but surely changing our future and shaping the computing environment around us. IoT integrated with advances in low cost computing, storage and power, along with high speed networks and big data, supports distributed computing. However, much like cloud computing, which are under constant security attacks and issues, distributed computing also faces similar challenges and security threats. This can be mitigated to a great extent using fog computing, which extends the limits of Cloud services to the last mile edge near to the nodes and networks, thereby increasing the performance and security levels. Fog computing also helps increase the reach and comes across as a viable solution for distributed computing. This article presents a review of the academic literature research work on the Fog Computing. The authors discuss the challenges in Fog environment and propose a new taxonomy.


2020 ◽  
Vol 10 (22) ◽  
pp. 8031
Author(s):  
Long Qin ◽  
Fanghao Huang ◽  
Zheng Chen ◽  
Wei Song ◽  
Shiqiang Zhu

Hyper-redundant continuum manipulators present dexterous kinematic skills in complicated tasks and demonstrate promising potential in underground exploration, intra-cavity inspection, surgery, etc. However, the hyper-redundancy, which endows much dexterity and flexibility, brings a huge challenge to the kinematics solution and control of the continuum manipulators. Due to the pseudoinverse calculation of high-order Jacobian matrix or iteration, many inverse kinematic solution approaches of continuum manipulators are very time-consuming, which extremely limit their applicability in real-time control. Additionally, it is often difficult for the manipulators to perform the tasks well in complex scenarios due to lack of human intervention. Therefore, in this paper, a simplified kinematics model of a typical hyper-redundant manipulator is proposed based on its unique geometry relationships, where the mapping relationships between the actuators’ rotation and the end-effector’s position are derived through the analysis of its driving subsystem and motion subsystem, in particular the joint modules. To perform the tasks of manipulators with the help of operators, a teleoperation control scheme with modified wave transmission structure is designed to achieve the guaranteed stability and improved transparency, and the leader’s trajectory and generated force feedback are the transmitted signals in the communication channel. Specifically, a virtual force feedback generation algorithm is developed in the teleoperation control scheme via the processing tracking errors, which can improve the operators’ assistance and perception during the teleoperation process. The practical experiments with comparative wave variable structures in two different sets are implemented to verify the effectiveness of proposed kinematics model and control scheme.


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