scholarly journals Weighted Interaction Force Estimation for Abnormality Detection in Crowd Scenes

2013 ◽  
pp. 507-518 ◽  
Author(s):  
Xiaobin Zhu ◽  
Jing Liu ◽  
Jinqiao Wang ◽  
Wei Fu ◽  
Hanqing Lu
Keyword(s):  
Interaction Force ◽  
Abnormality Detection ◽  
Force Estimation

scholarly journals Sensorless environment stiffness and interaction force estimation for impedance control tuning in robotized interaction tasks

2021 ◽  
Author(s):  
Loris Roveda ◽  
Dario Piga
Keyword(s):  
Impedance Control ◽  
Interaction Force ◽  
Industrial Robots ◽  
Force Estimation ◽  
Interaction Control ◽  
Stiffness Properties ◽  
Implementation Effort ◽  
Coupling Dynamics ◽  
And Control ◽  
Assembly Tasks

AbstractIndustrial robots are increasingly used to perform tasks requiring an interaction with the surrounding environment (e.g., assembly tasks). Such environments are usually (partially) unknown to the robot, requiring the implemented controllers to suitably react to the established interaction. Standard controllers require force/torque measurements to close the loop. However, most of the industrial manipulators do not have embedded force/torque sensor(s) and such integration results in additional costs and implementation effort. To extend the use of compliant controllers to sensorless interaction control, a model-based methodology is presented in this paper. Relying on sensorless Cartesian impedance control, two Extended Kalman Filters (EKF) are proposed: an EKF for interaction force estimation and an EKF for environment stiffness estimation. Exploiting such estimations, a control architecture is proposed to implement a sensorless force loop (exploiting the provided estimated force) with adaptive Cartesian impedance control and coupling dynamics compensation (exploiting the provided estimated environment stiffness). The described approach has been validated in both simulations and experiments. A Franka EMIKA panda robot has been used. A probing task involving different materials (i.e., with different - unknown - stiffness properties) has been considered to show the capabilities of the developed EKFs (able to converge with limited errors) and control tuning (preserving stability). Additionally, a polishing-like task and an assembly task have been implemented to show the achieved performance of the proposed methodology.

A Fresh Insight Into the Microcantilever-Sample Interaction Problem in Non-Contact Atomic Force Microscopy

2004 ◽  
Vol 126 (2) ◽  
pp. 327-335 ◽  
Author(s):  
Nader Jalili ◽  
Mohsen Dadfarnia ◽  
Darren M. Dawson
Keyword(s):  
Imaging Techniques ◽  
Interaction Force ◽  
Intermolecular Forces ◽  
Scanning Tunneling ◽  
Atomic Interaction ◽  
Force Estimation ◽  
Contact Mode ◽  
Distributed Parameters ◽  
Atomic Force ◽  
Insight Into

The atomic force microscope (AFM) system has evolved into a useful tool for direct measurements of intermolecular forces with atomic-resolution characterization that can be employed in a broad spectrum of applications. The non-contact AFM offers unique advantages over other contemporary scanning probe techniques such as contact AFM and scanning tunneling microscopy, especially when utilized for reliable measurements of soft samples (e.g., biological species). Current AFM imaging techniques are often based on a lumped-parameters model and ordinary differential equation (ODE) representation of the micro-cantilevers coupled with an adhoc method for atomic interaction force estimation (especially in non-contact mode). Since the magnitude of the interaction force lies within the range of nano-Newtons to pica-Newtons, precise estimation of the atomic force is crucial for accurate topographical imaging. In contrast to the previously utilized lumped modeling methods, this paper aims at improving current AFM measurement technique through developing a general distributed-parameters base modeling approach that reveals greater insight into the fundamental characteristics of the microcantilever-sample interaction. For this, the governing equations of motion are derived in the global coordinates via the Hamilton’s Extended Principle. An interaction force identification scheme is then designed based on the original infinite dimensional distributed-parameters system which, in turn, reveals the unmeasurable distance between AFM tip and sample surface. Numerical simulations are provided to support these claims.

Interaction Force Estimation Using Extended State Observers: An Application to Impedance-Based Assistive and Rehabilitation Robotics

2019 ◽  
Vol 4 (2) ◽  
pp. 1156-1161 ◽  
Author(s):  
Gijo Sebastian ◽  
Zeyu Li ◽  
Vincent Crocher ◽  
Demy Kremers ◽  
Ying Tan ◽  
...  
Keyword(s):  
Interaction Force ◽  
Rehabilitation Robotics ◽  
Extended State ◽  
Force Estimation ◽  
State Observers

scholarly journals Modeling, force estimation and control of steerable catheters for robot-assisted intra-cardiac navigation

2021 ◽  
Author(s):  
Shahir Hasanzadeh
Keyword(s):  
Contact Force ◽  
Position Control ◽  
Dynamic Environment ◽  
Region Of Interest ◽  
Interaction Force ◽  
Control Area ◽  
Target Tissue ◽  
Force Estimation ◽  
Control Scheme ◽  
Catheter Tip

Intra-cardiac catheterization is an effective procedure for diagnosis and treatment of many cardiac disorders such as arrhythmia. The objective of the catheter manipulation is to accurately position the catheter tip at the target tissue on the endocardium and provide a stable contact force for a specific duration to the region of interest. However, this is a challenging task due to the high flexibility of the catheter, ineffective visualization and dynamic environment of the heart. Additionally, the catheter-tissue interaction force, that the procedure outcome highly depends on, is not known to the interventionalist during the catheterization. This thesis deals with improving the safety and effectiveness of the catheterization by making contributions to two main areas; catheter contact force estimation and automatic force/position control of a robotic catheter system. First, a quasi-static model of the planar catheter that predicts the catheter pose for the given actuation variables and external forces in the plane of catheter motion, is proposed. In the next step, the computational efficiency of the proposed model is utilized to develop an online approach for the estimation of the external force at the tip of a catheter based on the pose measurement. The proposed force estimation approach is also extended to 3D by developing an efficient model of the catheter that is derived by coupling the classical Cosserat rod model with a new model of the pull-wire actuation. Experiments performed using electromagnetic sensors verify the feasibility of the proposed schemes in medical applications. In the control area, a position control scheme for a robotic assisted manipulation system is proposed, using the experimentally obtained inverse kinematics that compensates for the non-smooth dynamics of the distal shaft bending mechanism. Compensation of the backlash behavior of the catheter due to its interaction with the surrounding veins is also incorporated in the control scheme. The proposed position controller is then adopted as the internal loop of a hybrid position/force controller that positions the catheter tip to the target tissue and simultaneously, regulates the contact force to a desired value. The viability of the proposed controllers is then verified through simulations and experiments.

An Experimental and Analytical Investigation of a Prototype Isolation System for an Explosive Gas Operated Device and Interaction Force Estimation

2010 ◽  
Vol 224 (11) ◽  
pp. 2373-2381
Author(s):  
H-J Kim
Keyword(s):  
Human Body ◽  
Interaction Model ◽  
Interaction Force ◽  
Analytical Investigation ◽  
Human Interaction ◽  
Force Estimation ◽  
Isolation System ◽  
Transmitted Force ◽  
Series Of Experiments ◽  
Constrained Conditions

In this study, the optimal isolation system for the explosive gas operated device (EGOD) was investigated. Based on the analysis of the human body response induced by impulsive disturbances from the EGOD and the simplified human interaction model, a feasible isolation scheme has been presented and the prototype isolation system including the dynamic absorber has been constructed. In order to determine the parameters of that system, an optimization process was performed under constrained conditions. Finally, the performance of the designed prototype isolation system was evaluated in a series of experiments under actual utility condition, and the transmitted force from the EGOD to human body was predicted.

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