Feasibility Investigation of a Static Force Measurement with Longitudinal Piezoelectric Resonant Sensor

2009 ◽  
Vol 147-149 ◽  
pp. 876-881 ◽  
Author(s):  
Christophe Viguier ◽  
Clément Nadal ◽  
Jean François Rouchon
Keyword(s):  
Force Feedback ◽  
Force Measurement ◽  
Open Loop ◽  
Experimental Results ◽  
Frequency Variation ◽  
Variation Principle ◽  
Static Force ◽  
Stiffness Sensor ◽  
Definition Of ◽  
Langevin Transducer

Some applications, like force feedback joystick, require force measurement with high stiffness sensor to limit handle oscillations. In this way, this article presents an original technology to measure static force using the resonance frequency variation principle of a piezoelectric actuator subject to preload variation. We present in a first part comparison of various involved technologies to justify our choice (stiffness, inertia.....). The second part deals with the analytical modelling by variational principle of Langevin transducer. A comparison with the numerical FEM results is performed. Experimental results are then reached to validate the detailed concept. They demonstrate the potentiality of static force measurement with classical resonant structure like Langevin transducer with laboratory instruments. A last part is dedicated to the definition of an electronic to supply the sensor and to treat the measure. First experimental results are presented in an open loop electronic power supply configuration.

scholarly journals Cross-Modal Effect of Presenting Visual and Force Feedback That Create the Illusion of Stair-Climbing

2021 ◽  
Vol 11 (7) ◽  
pp. 2987
Author(s):  
Takumi Okumura ◽  
Yuichi Kurita
Keyword(s):  
Visual Information ◽  
Force Feedback ◽  
Activity Level ◽  
Experimental Results ◽  
Stair Climbing ◽  
Mirror Therapy ◽  
Visual Condition ◽  
Stroke Patients ◽  
Head Mount Display ◽  
The Brain

Image therapy, which creates illusions with a mirror and a head mount display, assists movement relearning in stroke patients. Mirror therapy presents the movement of the unaffected limb in a mirror, creating the illusion of movement of the affected limb. As the visual information of images cannot create a fully immersive experience, we propose a cross-modal strategy that supplements the image with sensual information. By interacting with the stimuli received from multiple sensory organs, the brain complements missing senses, and the patient experiences a different sense of motion. Our system generates the sense of stair-climbing in a subject walking on a level floor. The force sensation is presented by a pneumatic gel muscle (PGM). Based on motion analysis in a human lower-limb model and the characteristics of the force exerted by the PGM, we set the appropriate air pressure of the PGM. The effectiveness of the proposed system was evaluated by surface electromyography and a questionnaire. The experimental results showed that by synchronizing the force sensation with visual information, we could match the motor and perceived sensations at the muscle-activity level, enhancing the sense of stair-climbing. The experimental results showed that the visual condition significantly improved the illusion intensity during stair-climbing.

scholarly journals A Magnetorheological Fluids-Based Robot-Assisted Catheter/Guidewire Surgery System for Endovascular Catheterization

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 640
Author(s):  
Linshuai Zhang ◽  
Shuoxin Gu ◽  
Shuxiang Guo ◽  
Takashi Tamiya
Keyword(s):  
Collision Detection ◽  
Endovascular Procedures ◽  
Force Feedback ◽  
Force Measurement ◽  
Occupational Hazards ◽  
Robot Assisted ◽  
X Ray ◽  
Surgical Safety ◽  
Surgical Tool ◽  
Haptic Cues

A teleoperated robotic catheter operating system is a solution to avoid occupational hazards caused by repeated exposure radiation of the surgeon to X-ray during the endovascular procedures. However, inadequate force feedback and collision detection while teleoperating surgical tools elevate the risk of endovascular procedures. Moreover, surgeons cannot control the force of the catheter/guidewire within a proper range, and thus the risk of blood vessel damage will increase. In this paper, a magnetorheological fluid (MR)-based robot-assisted catheter/guidewire surgery system has been developed, which uses the surgeon’s natural manipulation skills acquired through experience and uses haptic cues to generate collision detection to ensure surgical safety. We present tests for the performance evaluation regarding the teleoperation, the force measurement, and the collision detection with haptic cues. Results show that the system can track the desired position of the surgical tool and detect the relevant force event at the catheter. In addition, this method can more readily enable surgeons to distinguish whether the proximal force exceeds or meets the safety threshold of blood vessels.

Impedance Reduction Controller Design for Mechanical Systems

2013 ◽  
Author(s):  
Hanseung Woo ◽  
Kyoungchul Kong
Keyword(s):  
Case Studies ◽  
Closed Loop ◽  
Controller Design ◽  
Mechanical Impedance ◽  
Open Loop ◽  
Mechatronic Systems ◽  
Closed Loop Systems ◽  
Guaranteed Stability ◽  
Reaction Forces ◽  
Definition Of

Safety is one of important factors in control of mechatronic systems interacting with humans. In order to evaluate the safety of such systems, mechanical impedance is often utilized as it indicates the magnitude of reaction forces when the systems are subjected to motions. Namely, the mechatronic systems should have low mechanical impedance for improved safety. In this paper, a methodology to design controllers for reduction of mechanical impedance is proposed. For the proposed controller design, the mathematical definition of the mechanical impedance for open-loop and closed-loop systems is introduced. Then the controllers are designed for stable and unstable systems such that they effectively lower the magnitude of mechanical impedance with guaranteed stability. The proposed method is verified through case studies including simulations.

Definition of the yield point in plasticity and its effect on the shape of the yield locus

1966 ◽  
Vol 1 (4) ◽  
pp. 331-338 ◽  
Author(s):  
T C Hsu
Keyword(s):  
Yield Point ◽  
Experimental Work ◽  
Strain Curve ◽  
Yield Locus ◽  
Experimental Results ◽  
Stress Strain Curve ◽  
Proportional Limit ◽  
Stress Strain ◽  
Small Section ◽  
Definition Of

Three different definitions of the yield point have been used in experimental work on the yield locus: proportional limit, proof strain and the ‘yield point’ by backward extrapolation. The theoretical implications of the ‘yield point’ by backward extrapolation are examined in an analysis of the loading and re-loading stress paths. It is shown, in connection with experimental results by Miastkowski and Szczepinski, that the proportional limit found by inspection is in fact a point located by backward extrapolation based on a small section of the stress-strain curve, near the elastic portion of the curve. The effect of different definitions of the yield point on the shape of the yield locus and some considerations for the choice between them are discussed.

Design and control of 2-DoF joystick using MR-fluid rotary actuator

2021 ◽  
pp. 1045389X2110639
Author(s):  
Bao Tri Diep ◽  
Quoc Hung Nguyen ◽  
Thanh Danh Le
Keyword(s):  
Pid Controller ◽  
Force Feedback ◽  
Control Method ◽  
Open Loop ◽  
Friction Torque ◽  
Feedback Controls ◽  
Loop Control ◽  
Fuzzy Logic Algorithm ◽  
Experimental Apparatus ◽  
Close Loop Control

The purpose of this paper is to design a control algorithm for a 2-DoF rotary joystick model. Firstly, the structure of the joystick, which composes of two magneto-rheological fluid actuators (shorten MRFA) with optimal configuration coupled perpendicularly by the gimbal mechanism to generate the friction torque for each independent rotary movement, is introduced. The control strategy of the designed joystick is then suggested. Really, because of two independent rotary movements, it is necessary to design two corresponding controllers. Due to hysteresis and nonlinear dynamic characteristics of the MRFA, controllers based an accurate dynamic model are difficult to realize. Hence, to release this issue, the proposed controller (named self-turning fuzzy controllers-STFC) will be built through the fuzzy logic algorithm in which the parameters of controllers are learned and trained online by Levenberg-Marquardt training algorithm. Finally, an experimental apparatus will be constructed to assess the effectiveness of the force feedback controls. Herein, three experimental cases are performed to compare the control performance of open-loop and close-loop control method, where the former is done through relationship between the force at the knob and the current supplied to coil while the latter is realized based on the proposed controller and PID controller. The experimental results provide strongly the ability of the proposed controller, meaning that the STFC is robust and tracks well the desirable force with high accuracy compared with both the PID controller and the open-loop control method.

scholarly journals Static Force Measurement Using Piezoelectric Sensors

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Kyungrim Kim ◽  
Jinwook Kim ◽  
Xiaoning Jiang ◽  
Taeyang Kim
Keyword(s):  
Surface Charge ◽  
Piezoelectric Effect ◽  
Force Measurement ◽  
Piezoelectric Materials ◽  
Force Sensor ◽  
Piezoelectric Sensors ◽  
Force Sensing ◽  
Static Force ◽  
Sensing Applications ◽  
Direct Piezoelectric Effect

In force measurement applications, a piezoelectric force sensor is one of the most popular sensors due to its advantages of low cost, linear response, and high sensitivity. Piezoelectric sensors effectively convert dynamic forces to electrical signals by the direct piezoelectric effect, but their use has been limited in measuring static forces due to the easily neutralized surface charge. To overcome this shortcoming, several static (either pure static or quasistatic) force sensing techniques using piezoelectric materials have been developed utilizing several unique parameters rather than just the surface charge produced by an applied force. The parameters for static force measurement include the resonance frequency, electrical impedance, decay time constant, and capacitance. In this review, we discuss the detailed mechanism of these piezoelectric-type, static force sensing methods that use more than the direct piezoelectric effect. We also highlight the challenges and potentials of each method for static force sensing applications.

Sensorless Force Control Interface for DEAP Stack-Actuators

2015 ◽  
Author(s):  
Thorben Hoffstadt ◽  
Jürgen Maas
Keyword(s):  
Force Control ◽  
Electromechanical Coupling ◽  
Force Measurement ◽  
Scale Up ◽  
Electroactive Polymers ◽  
Open Loop ◽  
Control Interface ◽  
Electromechanical Drive ◽  
Electrostatic Pressure ◽  
Drive Systems

Transducers based on dielectric electroactive polymers (DEAP) offer an attractive balance of work density and electromechanical efficiency. For example in automation and haptic applications, especially multilayer transducers are used to scale up their absolute deformation and force. Depending on the application different transducer controls have to be realized to match the specifications of the particular application. However, analogous to conventional electromechanical drive systems an inner sensor-less force control can be realized for DEAP transducers, too. For this force control the nonlinear relations between voltage and electrostatic pressure as well as the electromechanical coupling have to be considered. The resulting open-loop force control can be used for superimposed motion controls, such as position, vibration and impedance controls. Therefore, within this contribution the authors propose a model-based feedforward force control based on an overall model of the transducer that does not require any force measurement. Finally, the derived open-loop force control interface is experimentally validated using in-house developed DEAP stack-transducers and driving power electronics.

Oxygen Enrichment in Combustion Processes: Comparative Experimental Results From Several Application Fields

1991 ◽  
Vol 113 (2) ◽  
pp. 122-126
Author(s):  
M. De Lucia
Keyword(s):  
Energy Consumption ◽  
Energy Savings ◽  
Copper Alloys ◽  
Ceramic Materials ◽  
Oxygen Enrichment ◽  
Experimental Results ◽  
Ferrous Metals ◽  
Definition Of ◽  
Application Fields ◽  
Combustion Processes

The effects of using oxygen to partially or wholly replace fuel air in small-size melting furnaces were studied over a range of application fields. Following definition of the useful parameters, testing was conducted on furnaces for melting glass, ferrous metals (pigiron), nonferrous metals (copper alloys), and ceramic materials. In all cases, oxygen-enrichment was found to provide significant energy savings, as well as notable advantages in terms of both plant output and energy consumption.

Looking for Patterns

2021 ◽  
pp. 57-73
Author(s):  
Talia Dan-Cohen
Keyword(s):  
Life Forms ◽  
Experimental Results ◽  
Close Attention ◽  
Vast Array ◽  
Observational Skills ◽  
Definition Of ◽  
By Products

This chapter focuses on ambiguous experimental results, paying close attention to experimental processes and tracking the ways that practitioners tackle, reason, and think through puzzling experimental results. It investigates the context of experiments with modified life-forms and experimental results that take the form of a vast array of biotic not-quites. It also highlights organismic by-products that point in various directions when it comes to figuring out how much control synthetic biologists have over their designs and what steps should be taken as correctives. The chapter explains how experiments often come packaged together with the choices, standards, and observational skills of others. It discusses the problem of the definition of growth that was deferred through the delineation of a category for the indeterminate results.

Roaming Reactions and Dynamics in the van der Waals Region

2020 ◽  
Vol 71 (1) ◽  
pp. 77-100 ◽  
Author(s):  
Arthur G. Suits
Keyword(s):  
Long Range ◽  
Internal State ◽  
Chemical Reactivity ◽  
Van Der Waals ◽  
Quantum Effects ◽  
Experimental Results ◽  
Unexpected Formation ◽  
Chemical Systems ◽  
Definition Of

Roaming reactions were first clearly identified in photodissociation of formaldehyde 15 years ago, and roaming dynamics are now recognized as a universal aspect of chemical reactivity. These reactions typically involve frustrated near-dissociation of a quasibound system to radical fragments, followed by reorientation at long range and intramolecular abstraction. The consequences can be unexpected formation of molecular products, depletion of the radical pool in chemical systems, and formation of products with unusual internal state distributions. In this review, I examine some current aspects of roaming reactions with an emphasis on experimental results, focusing on possible quantum effects in roaming and roaming dynamics in bimolecular systems. These considerations lead to a more inclusive definition of roaming reactions as those for which key dynamics take place at long range.

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