Excalibur, a Three-Axis Force Display

1999 ◽  
Author(s):  
Richard J. Adams ◽  
Manuel R. Moreyra ◽  
Blake Hannaford
Keyword(s):  
Force Feedback ◽  
Digital Simulation ◽  
Haptic Display ◽  
Haptic Displays ◽  
Interface Modeling ◽  
Modal Behavior ◽  
And Performance ◽  
The Stability ◽  
Representative Points ◽  
Haptic Simulation

Abstract In haptic simulation, a force feedback device is combined with a digital representation of a virtual world to create a kinesthetically immersive experience. The force feedback device, or haptic display, is usually a robotic manipulator with which a human operator interacts physically through a handle, stylus, finger-pad or some other form of customized interface. Modeling of the haptic display is often overlooked when building a haptic simulation. Understanding the dynamic behavior of the device is critical in assessing the stability and performance of the overall system as well as in the construction of the digital simulation. This paper describes some of the special modeling requirements for haptic displays. A dynamic model for Excalibur, a new three axis force display, is developed in a two step process. First an analytical model is constructed based on measured values and basic principals. Then the model is tuned using the results of vibrational testing to achieve a close match between the modal behavior of the theoretical and real systems. Numerical and experimental results are presented for representative points in the device’s workspace.

Stability and Performance of Virtual Reality-Based Telenanomanipulation System in SEM

2011 ◽  
Vol 183-185 ◽  
pp. 1746-1751 ◽  
Author(s):  
Dong Jie Li ◽  
Wei Bin Rong ◽  
Li Ning Sun ◽  
Wan Zhe Xiao
Keyword(s):  
Force Feedback ◽  
Design Procedure ◽  
Haptic Interface ◽  
Human Contact ◽  
Virtual Coupling ◽  
And Performance ◽  
The Stability ◽  
Carbon Nanowires ◽  
Measuring Force ◽  
Scanning Electron

In this paper, a master/slave telenanomanipulation control system with force feedback is established with the micro-positioner (Attocube) working in scanning electron microscope (SEM) as the slave side and the haptic device (Omega3) as the master side. An improved virtual coupling (IVC) algorithm is introduced based on nanoscale virtual coupling (NSVC) by adding a proportional- plus-integral (PI) velocity controller in the haptic interface. The stability and performance of the established system are discussed. This method leads to an explicit design procedure for virtual coupling networks which give greatest performance while guaranteeing stability both on moving carbon nanowires in SEM and measuring force at the point of device-human contact.

Neural-net tuned PID control of a parallel type mechanism with force feedback for virtual reality applications

Robotica ◽  
2004 ◽  
Vol 22 (3) ◽  
pp. 319-327 ◽  
Author(s):  
M. Karkoub ◽  
M.-G. Her ◽  
K.-S. Hsu ◽  
C.-Y. Chen
Keyword(s):  
Virtual Reality ◽  
Force Feedback ◽  
Robot Manipulator ◽  
Virtual Object ◽  
Neural Net ◽  
Stabilizing Controller ◽  
Human Interface ◽  
Nyquist Stability ◽  
And Performance ◽  
The Stability

This paper explores a new type of a parallel platform human interface manipulator based on virtual reality (VR) for mechanism design applications. A motion control of a six-link robot manipulator actuated by three active joints is presented here. The main components of the system include a user interface, a software simulating the environment, and a VR control system. The model of the VR system is built based on a force feedback behavior that enables the operator to feel the actual force feedback from the virtual environment just as he/she would from the real environment. A primary stabilizing controller is used to develop a haptic interface device where realistic simulations of the dynamic interaction forces between a human operator and the simulated virtual object/mechanism is required. The stability and performance of the system are studied and analyzed based on the Nyquist stability criterion. Experiments on cutting virtual clay are used to validate the theoretical developments. It was shown that the experimental and theoretical results are in good agreement.

Stability and performance of haptic simulation involving interaction with non-passive virtual environment

Robotica ◽  
2018 ◽  
Vol 37 (3) ◽  
pp. 560-574 ◽  
Author(s):  
Myeongjin Kim ◽  
Doo Yong Lee
Keyword(s):  
Virtual Environment ◽  
Stability Condition ◽  
Virtual Tools ◽  
Maximum Stiffness ◽  
Force Mapping ◽  
Six Dof ◽  
Analysis Of Stability ◽  
And Performance ◽  
The Stability ◽  
Haptic Simulation

SUMMARYPrevious researches on analysis of stability of haptic simulation largely assume that the virtual environment is passive. But the virtual environment can become non-passive due to various reasons including discretization errors and interaction dynamics between virtual tools and objects. This paper provides an analysis of the stability and performance of the haptic simulation involving non-passive virtual environment. The dynamic interaction between the virtual tools and the objects is modeled using the two-port networks. The analysis is carried out using a velocity and force mapping matrix for six-DOF simulation. New stability condition resulting from the analysis is applied to an example simulation of a one-DOF virtual wall. Maximum stiffness satisfying the stability condition established in the previous literature, and the proposed condition is compared with the maximum stiffness experimentally determined with various time steps. The newly proposed stability condition manifests less standard deviation of errors than the widely applied absolute stability condition.

scholarly journals Three-Axis Pneumatic Haptic Display for the Mechanical and Thermal Stimulation of a Human Finger Pad

Actuators ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 60
Author(s):  
Eun-Hyuk Lee ◽  
Sang-Hoon Kim ◽  
Kwang-Seok Yun
Keyword(s):  
Pulse Width Modulation ◽  
Haptic Feedback ◽  
Control Function ◽  
Lateral Displacement ◽  
Gain Control ◽  
Haptic Display ◽  
Positional Accuracy ◽  
Control Module ◽  
Haptic Displays ◽  
Human Finger

Haptic displays have been developed to provide operators with rich tactile information using simple structures. In this study, a three-axis tactile actuator capable of thermal display was developed to deliver tactile senses more realistically and intuitively. The proposed haptic display uses pneumatic pressure to provide shear and normal tactile pressure through an inflation of the balloons inherent in the device. The device provides a lateral displacement of ±1.5 mm for shear haptic feedback and a vertical inflation of the balloon of up to 3.7 mm for normal haptic feedback. It is designed to deliver thermal feedback to the operator through the attachment of a heater to the finger stage of the device, in addition to mechanical haptic feedback. A custom-designed control module is employed to generate appropriate haptic feedback by computing signals from sensors or control computers. This control module has a manual gain control function to compensate for the force exerted on the device by the user’s fingers. Experimental results showed that it could improve the positional accuracy and linearity of the device and minimize hysteresis phenomena. The temperature of the device could be controlled by a pulse-width modulation signal from room temperature to 90 °C. Psychophysical experiments show that cognitive accuracy is affected by gain, and temperature is not significantly affected.

scholarly journals Analytical Modeling and Design of Novel Conical Halbach Permanent Magnet Couplings for Underwater Propulsion

2021 ◽  
Vol 9 (3) ◽  
pp. 290
Author(s):  
Yukai Li ◽  
Yuli Hu ◽  
Youguang Guo ◽  
Baowei Song ◽  
Zhaoyong Mao
Keyword(s):  
Permanent Magnet ◽  
Analytical Calculation ◽  
Underwater Propulsion ◽  
Conical Structure ◽  
Torque Analysis ◽  
Dynamic Seal ◽  
And Performance ◽  
The Stability ◽  
Propulsion Unit ◽  
Force Calculation

Permanent magnet couplings can convert a dynamic seal into a static seal, thereby greatly improving the stability of the underwater propulsion unit. In order to make full use of the tail space and improve the transmitted torque capability, a conical Halbach permanent magnet coupling (C-HPMC) is proposed in this paper. The C-HPMC combines multiple cylindrical HPMCs with different sizes into an approximately conical structure. Compared with the conical permanent magnet couplings in our previous work, the novel C-HPMC has better torque performance and is easy to process. The analytical calculation method of transmitted torque of C-HPMC is proposed on the basis of torque calculation of the three common types of HPMCs. The accuracy of the torque calculation of the three HPMCs is verified, and the torque performance of the three HPMCSs of different sizes is compared and discussed. The “optimal type selection” method is proposed and applied in the design of C-HPMC. Finally, on the basis of torque analysis calculation and axial force calculation, a complete flowchart of the design and performance analysis of C-HPMC is described.

scholarly journals The Application of an Impedance-Passivity Controller in Haptic Stability Analysis

2021 ◽  
Vol 11 (4) ◽  
pp. 1618
Author(s):  
Ping-Nan Chen ◽  
Yung-Te Chen ◽  
Hsin Hsiu ◽  
Ruei-Jia Chen
Keyword(s):  
Control Systems ◽  
Force Feedback ◽  
Training System ◽  
Considerable Time ◽  
Virtual Training ◽  
Control Gain ◽  
Negative Damping ◽  
The Stability ◽  
Time Required ◽  
Stable Control

This paper proposes a passivity theorem on the basis of energy concepts to study the stability of force feedback in a virtual haptic system. An impedance-passivity controller (IPC) was designed from the two-port network perspective to improve the chief drawback of haptic systems, namely the considerable time required to reach stability if the equipment consumes energy slowly. The proposed IPC can be used to achieve stability through model parameter selection and to obtain control gain. In particular, haptic performance can be improved for extreme cases of high stiffness and negative damping. Furthermore, a virtual training system for one-degree-of-freedom sticking was developed to validate the experimental platform of our IPC. To ensure consistency in the experiment, we designed a specialized mechanical robot to replace human operation. Finally, compared with basic passivity control systems, our IPC could achieve stable control rapidly.

Adaptive attitude-tracking control of spacecraft considering on-orbit refuelling

2020 ◽  
pp. 014233122097313
Author(s):  
Yiqi Xu
Keyword(s):  
Tracking Control ◽  
Closed Loop ◽  
Closed Loop System ◽  
Tracking Errors ◽  
Attitude Tracking ◽  
Control Scheme ◽  
Inertia Model ◽  
And Performance ◽  
Attitude Tracking Control ◽  
The Stability

This paper studies the attitude-tracking control problem of spacecraft considering on-orbit refuelling. A time-varying inertia model is developed for spacecraft on-orbit refuelling, which actually includes two processes: fuel in the transfer pipe and fuel in the tank. Based upon the inertia model, an adaptive attitude-tracking controller is derived to guarantee the stability of the resulted closed-loop system, as well as asymptotic convergence of the attitude-tracking errors, despite performing refuelling operations. Finally, numerical simulations illustrate the effectiveness and performance of the proposed control scheme.

Nondestructive Test on Typical Roadway Supports of a Mine via Drilling Core and Ground Penetrating Radar

2011 ◽  
Vol 368-373 ◽  
pp. 2411-2416
Author(s):  
Jian Ping Han ◽  
Hai Peng Liu
Keyword(s):  
Ground Penetrating Radar ◽  
Geological Structure ◽  
Surrounding Rock ◽  
Potential Threat ◽  
Real Performance ◽  
Design Requirements ◽  
And Performance ◽  
The Stability ◽  
Ground Penetrating ◽  
Drilling Core

Temporary or permanent supports are necessary in underground construction for maintaining the stability and limiting the damage of surrounding rock. Due to the uncertainty of geological structure, the specificity of the underground environment as well as other factors, the quality and performance of supporting structure are often difficult to satisfy the design requirements, which not only seriously affects the normal construction and operation of mines but also has the potential threat to the safety of underground production. In order to investigate the influence of the unfavorable geologic environment on supporting concrete and evaluate the real performance of roadway supports of a mine, 17 typical projects were chosen and the strength of supporting concrete was detected by nondestructive drilling core method. The result shows that the strength is widely less than the design value. Furthermore, 4 projects of them were investigated by the ground penetrating radar (GPR) in order to evaluate the feasibility of GPR in the performance investigation of the roadway supports of a mine. The results indicate that ground penetrating radar is capable of measuring the thickness of the support, the distribution of rebars and the defects of the surrounding rock.

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