scholarly journals Real-time dynamics of soft and continuum robots based on Cosserat rod models

2019 ◽  
Vol 38 (6) ◽  
pp. 723-746 ◽  
Author(s):  
John Till ◽  
Vincent Aloi ◽  
Caleb Rucker
Keyword(s):  
Real Time ◽  
High Speed ◽  
Dynamic Models ◽  
Numerical Approach ◽  
Dynamics Simulation ◽  
Working Fluid ◽  
Implicit Methods ◽  
Camera System ◽  
Time Dynamics ◽  
Cosserat Rod

The dynamic equations of many continuum and soft robot designs can be succinctly formulated as a set of partial differential equations (PDEs) based on classical Cosserat rod theory, which includes bending, torsion, shear, and extension. In this work we present a numerical approach for forward dynamics simulation of Cosserat-based robot models in real time. The approach implicitly discretizes the time derivatives in the PDEs and then solves the resulting ordinary differential equation (ODE) boundary value problem (BVP) in arc length at each timestep. We show that this strategy can encompass a wide variety of robot models and numerical schemes in both time and space, with minimal symbolic manipulation required. Computational efficiency is gained owing to the stability of implicit methods at large timesteps, and implementation is relatively simple, which we demonstrate by providing a short MATLAB-coded example. We investigate and quantify the tradeoffs associated with several numerical subroutines, and we validate accuracy compared with dynamic rod data gathered with a high-speed camera system. To demonstrate the method’s application to continuum and soft robots, we derive several Cosserat-based dynamic models for robots using various actuation schemes (extensible rods, tendons, and fluidic chambers) and apply our approach to achieve real-time simulation in each case, with additional experimental validation on a tendon robot. Results show that these models capture several important phenomena, such as stability transitions and the effect of a compressible working fluid.

A Low-Cost Real-Time Man-in-the-Loop Simulation for Multibody Systems

1989 ◽  
Author(s):  
J. L. Chang ◽  
S. S. Kim
Keyword(s):  
Real Time ◽  
High Speed ◽  
Low Cost ◽  
Equations Of Motion ◽  
Time Integration ◽  
Visual Display ◽  
Dynamics Simulation ◽  
Integration Algorithm ◽  
Multiprocessor Computer ◽  
Time Dynamics

Abstract This paper presents a general approach for achieving real-time man-in-the-loop simulation for multibody dynamic systems. Emerging real-time dynamics simulation technologies are exploited to develop a low-cost network based simulator as an interactive design workstation with a human operator in the control loop. An efficient recursive dynamic formulation is used to create multibody dynamics models. A parallel processing algorithm is developed based on the recursive dynamics formulation and implemented on a multiprocessor computer to achieve real-time simulation. As a real-time integration algorithm, third-order Adams-Bashforth method is used. The integration stepsize is estimated from the eigenvalue analysis of the equations of motion. High speed computer graphics techniques provide realistic visual display for the simulator. A backhoe simulation is implemented as an example to demonstrate the feasibility of man-in-the-loop simulation on the low-cost simulator.

scholarly journals Real-space and real-time dynamics of CRISPR-Cas9 visualized by high-speed atomic force microscopy

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Mikihiro Shibata ◽  
Hiroshi Nishimasu ◽  
Noriyuki Kodera ◽  
Seiichi Hirano ◽  
Toshio Ando ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Real Time ◽  
High Speed ◽  
Real Space ◽  
Time Dynamics ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals Real-time high-resolution video stabilization using high-frame-rate jitter sensing

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Sushil Raut ◽  
Kohei Shimasaki ◽  
Sanjay Singh ◽  
Takeshi Takaki ◽  
Idaku Ishii
Keyword(s):  
High Resolution ◽  
Real Time ◽  
High Speed ◽  
Image Sequences ◽  
Frame Rate ◽  
Video Stabilization ◽  
Feature Points ◽  
Cmos Camera ◽  
Camera System ◽  
Digital Video Stabilization

AbstractIn this study, the novel approach of real-time video stabilization system using a high-frame-rate (HFR) jitter sensing device is demonstrated to realize the computationally efficient technique of digital video stabilization for high-resolution image sequences. This system consists of a high-speed camera to extract and track feature points in gray-level $$512\times 496$$512×496 image sequences at 1000 fps and a high-resolution CMOS camera to capture $$2048\times 2048$$2048×2048 image sequences considering their hybridization to achieve real-time stabilization. The high-speed camera functions as a real-time HFR jitter sensing device to measure an apparent jitter movement of the system by considering two ways of computational acceleration; (1) feature point extraction with a parallel processing circuit module of the Harris corner detection and (2) corresponding hundreds of feature points at the current frame to those in the neighbor ranges at the previous frame on the assumption of small frame-to-frame displacement in high-speed vision. The proposed hybrid-camera system can digitally stabilize the $$2048\times 2048$$2048×2048 images captured with the high-resolution CMOS camera by compensating the sensed jitter-displacement in real time for displaying to human eyes on a computer display. The experiments were conducted to demonstrate the effectiveness of hybrid-camera-based digital video stabilization such as (a) verification when the hybrid-camera system in the pan direction in front of a checkered pattern, (b) stabilization in video shooting a photographic pattern when the system moved with a mixed-displacement motion of jitter and constant low-velocity in the pan direction, and (c) stabilization in video shooting a real-world outdoor scene when an operator holding hand-held hybrid-camera module while walking on the stairs.

Workstation-Based Man-in-the-Loop Simulation for Multibody Systems

1990 ◽  
Author(s):  
J. L. Chang ◽  
S. S. Kim
Keyword(s):  
Real Time ◽  
Dynamic Simulation ◽  
High Speed ◽  
Visual Cues ◽  
Parallel Computer ◽  
Hydraulic Systems ◽  
Recursive Formulation ◽  
Time Dynamic ◽  
Time Dynamics ◽  
Operator Interface

Abstract This paper presents a general approach to achieving real-time man-in-the-loop simulation for multibody dynamic systems. Emerging real-time dynamic simulation methods are used to demonstrate the potential for creating interactive design workstations with a human operator in the control loop. The recursive formulation of multibody system dynamics with relative coordinates is employed for efficient numerical analysis and implementation on parallel computer. A workstation-based simulator is developed by integrating the real-time dynamics program, a realistic graphics display, and the operator’s control interface. High speed computer graphics techniques are employed to create realistic visual cues for the simulator. Real-time man-in-the-loop simulation is analyzed, as regards the goal of real clock time, not only with respect to dynamic simulation but also with respect to graphics display and the operator interface. Synchronization of the simulation is found to be most important for realism of the simulator. A backhoe simulation is implemented to demonstrate the capability for man-in-the-loop simulation. The backhoe simulator is developed by modeling backhoe dynamics and hydraulic systems with the recursive formulation to achieve real-time simulation, developing an interactive graphics program for visual cues, and interfacing the operator’s control action with the dynamic simulation through a pair of joysticks.

scholarly journals Directions of Development of Intelligent Real Time Video Systems

2017 ◽  
Vol 2 (3) ◽  
pp. 48 ◽  
Author(s):  
Vitaliy Boyun
Keyword(s):  
Information Processing ◽  
Real Time ◽  
High Speed ◽  
Dynamic Models ◽  
Visual Analyzer ◽  
Retinal Neuron ◽  
Neuron Network ◽  
Range Interaction ◽  
Video Information ◽  
Video Systems

Real time video systems play a significant role in many fields of science and technology.  The range of their applications is constantly increasing together with requirements to them, especially it concerns to real time video systems with the feedbacks. Conventional fundamentals and principles of real-time video systems construction are extremely redundant and do not take into consideration the peculiarities of real time processing and tasks, therefore they do not meet the system requirements neither in technical plan nor in informational and methodical one. Therefore, the purpose of this research is to increase responsiveness, productivity and effectiveness of real time video systems with a feedback during the operation with the high-speed objects and dynamic processes. The human visual analyzer is considered as a prototype for the construction of intelligent real time video systems. Fundamental functions, structural and physical peculiarities of adaptation and processes taking place in a visual analyzer relating to the information processing, are considered. High selectivity of information perception and wide parallelism of information processing on the retinal neuron layers and on the higher brain levels are most important peculiarities of a visual analyzer for systems with the feedback. The paper considers two directions of development of intelligent real time video systems. First direction based on increasing intellectuality of video systems at the cost of development of new information and dynamic models for video information perception processes, principles of control and reading parameters of video information from the sensor, adapting them to the requirements of concrete task, and combining of input processes with data processing. Second direction is associated with the development of new architectures for parallel perception and level-based processing of information directly on a video sensor matrix. The principles of annular and linear structures on the neurons layers, of close-range interaction and specialization of layers, are used to simplify the neuron network.

scholarly journals Rigid-body fitting to atomic force microscopy images for inferring probe shape and biomolecular structure

2021 ◽  
Author(s):  
Toru Niina ◽  
Yasuhiro Matsunaga ◽  
Shoji Takada
Keyword(s):  
Atomic Force Microscopy ◽  
Rigid Body ◽  
Real Time ◽  
High Speed ◽  
Surface Shape ◽  
Time Dynamics ◽  
Force Microscopy ◽  
Small Proteins ◽  
Atomic Force ◽  
Functional Dynamics

AbstractHigh-speed (HS) atomic force microscopy (AFM) can visualize real-time dynamics of functional biomolecules near the physiological condition, but the observed data are limited to the surface height of specimens. Since the HS-AFM images highly depend on the probe tip shape, for successful inference of molecular structures from the measurement, the knowledge of the probe shape is required, but is often missing. Here, we developed a method of the rigid-body fitting to HS-AFM images, which simultaneously finds the shape of the probe tip and the placement of the molecular structure via an exhaustive search. We examined four similarity scores via twin-experiments for four test proteins: Of the four scores, the cosine similarity generally worked best, whereas the pixel-RMSD was also useful especially for the placement of small proteins. We then applied the method to two experimental HS-AFM images inferring the probe shape and the molecular placement. The inferred tip shape and placement results can be further refined by other methods, such as the flexible fitting molecular dynamics simulations. The developed software is publicly available.Author SummaryObservation of functional dynamics of individual biomolecules is important to understand molecular mechanisms of cellular phenomena. High-speed (HS) atomic force microscopy (AFM) is a powerful tool that enables us to visualize the real-time dynamics of working biomolecules under near-physiological conditions. However, the information available by the HS-AFM images is limited to the two-dimensional surface shape detected via the force to the probe. While the surface information is affected by the shape of the probe tip, the probe shape itself cannot be directly measured before each HS-AFM measurement. To overcome this problem, we have developed a computational method to simultaneously infer the probe tip shape and the molecular placement from an HS-AFM image. We show that our method successfully estimates the effective HS-AFM tip shape and visualizes a structure with a more accurate placement. The estimation of a molecular placement with the correct probe tip shape enables us to obtain more insights into functional dynamics of the molecule from HS-AFM images.

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