Identifying Stiffness, Friction, and Kinematic Error Signature in Gear Bearing Drive Transmissions

2018 ◽  
Author(s):  
Elias Brassitos ◽  
Nader Jalili
Keyword(s):  
Gear Ratio ◽  
Open Loop ◽  
Reduction Gear ◽  
Kinematic Error ◽  
High Reduction ◽  
Stiffness Characteristics ◽  
Drive Systems ◽  
Ratio Transmission ◽  
Speed Response

The Gear Bearing Drive (GBD) is a recently developed high gear-ratio transmission concept based on NASA’s high-reduction gear bearing technology and brushless outrunner motor technology. In this paper, we describe the experimental setup and characterization of the GBD transmission’s stiffness, friction, backlash, hysteresis as well as its kinematic error. Compared to conventional precision drive systems such as harmonic drives, the GBD can offer similar advantages such as high gear-ratio in a compact assembly but with the potential of better stiffness characteristics and a more predictable output speed response. The models derived in this paper were then fed into a dynamic model that can accurately simulate the velocity open-loop response of the transmission under various input current functions.

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.

scholarly journals The Fabrication and Characterization of InAlAs/InGaAs APDs Based on a Mesa-Structure with Polyimide Passivation

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3399 ◽  
Author(s):  
Jheng-Jie Liu ◽  
Wen-Jeng Ho ◽  
June-Yan Chen ◽  
Jian-Nan Lin ◽  
Chi-Jen Teng ◽  
...  
Keyword(s):  
Electric Fields ◽  
High Speed ◽  
Gain Bandwidth ◽  
Mesa Structure ◽  
Multiplication Gain ◽  
Data Rates ◽  
Field Control ◽  
Side Walls ◽  
Speed Response

This paper presents a novel front-illuminated InAlAs/InGaAs separate absorption, grading, field-control and multiplication (SAGFM) avalanche photodiodes (APDs) with a mesa-structure for high speed response. The electric fields in the InAlAs-multiplication layer and InGaAs-absorption layer enable high multiplication gain and high-speed response thanks to the thickness and concentration of the field-control and multiplication layers. A mesa active region of 45 micrometers was defined using a bromine-based isotropic wet etching solution. The side walls of the mesa were subjected to sulfur treatment before being coated with a thick polyimide layer to reduce current leakage, while lowering capacitance and increasing response speeds. The breakdown voltage (VBR) of the proposed SAGFM APDs was approximately 32 V. Under reverse bias of 0.9 VBR at room temperature, the proposed device achieved dark current of 31.4 nA, capacitance of 0.19 pF and multiplication gain of 9.8. The 3-dB frequency response was 8.97 GHz and the gain-bandwidth product was 88 GHz. A rise time of 42.0 ps was derived from eye-diagrams at 0.9 VBR. There was notable absence of intersymbol-interference and the signals remained error-free at data-rates of up to 12.5 Gbps.

Design and characterization of a hybrid soft gripper with active palm pose control

2020 ◽  
Vol 39 (14) ◽  
pp. 1668-1685 ◽  
Author(s):  
Vignesh Subramaniam ◽  
Snehal Jain ◽  
Jai Agarwal ◽  
Pablo Valdivia y Alvarado
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Composite Structure ◽  
Element Model ◽  
Open Loop ◽  
Aspect Ratios ◽  
Maximum Payload ◽  
Wide Range ◽  
Pose Control

The design and characterization of a soft gripper with an active palm to control grasp postures is presented herein. The gripper structure is a hybrid of soft and stiff components to facilitate integration with traditional arm manipulators. Three fingers and a palm constitute the gripper, all of which are vacuum actuated. Internal wedges are used to tailor the deformation of a soft outer reinforced skin as vacuum collapses the composite structure. A computational finite-element model is proposed to predict finger kinematics. Thanks to its active palm, the gripper is capable of grasping a wide range of part geometries and compliances while achieving a maximum payload of 30 N. The gripper natural softness enables robust open-loop grasping even when components are not properly aligned. Furthermore, the grasp pose of objects with various aspect ratios and compliances can be robustly maintained during manipulation at linear accelerations of up to 15 m/s2 and angular accelerations of up to 5.23 rad/s2.

Computer aided models for the characterization of synchronous reluctance motor drive systems

1999 ◽  
Vol 14 (4) ◽  
pp. 1459-1464 ◽  
Author(s):  
A.A. Arkadan ◽  
F.N. Isaac ◽  
A.A. Russell ◽  
A. El-Antably ◽  
N.A. Demerdash
Keyword(s):  
Motor Drive ◽  
Synchronous Reluctance Motor ◽  
Reluctance Motor ◽  
Computer Aided ◽  
Drive Systems

High-Reduction, High-Torque Gear Reducer Design Emphasizes Compactness

2003 ◽  
Author(s):  
Jim B. Surjaatmadja ◽  
James C. Tucker
Keyword(s):  
Fluid Flow ◽  
Gear Tooth ◽  
Planetary Gear ◽  
Reduction Gear ◽  
Multi Stage ◽  
Full Contact ◽  
High Reduction ◽  
High Torque ◽  
Standard Designs ◽  
Oilfield Equipment

The design of high-torque, high-reduction gear reducers often requires the use of multi-stage gearing, planetary gear systems, or both. Because these systems contain many independent parts, they often become bulky. When these systems will be used in downhole oilfield equipment, compactness can become a crucial factor. Moreover, downhole oilfield equipment generally requires that areas of the system be reserved to provide some fluid flow-path around the equipment. A unique gear reducer was designed to accommodate this need for compactness. The new reducer system consists of only four gears, two of which are built as a single part. All four gears are positioned roughly concentrically within a donut-like space, and the open center accommodates fluid flow. Unlike other gear reducer systems, this system employs not only a ratio (divisional) method, but also a unique subtraction method. Consequently, a reduction of more than 2000:1 is possible. With this radical design, conventional gear teeth cannot be used if good meshing is desired. Subsequently, a special gear tooth shape was designed to provide surface contact between the teeth. With this special shape, full contact of more than 30% of the teeth can be achieved, compared to one or two teeth in standard designs. Thus, the new system also improves load-transmitting capacity. In this paper, the design of the new gear reducer is discussed in detail. A specific application in which high-pressure, sand-laden slurry is pumped through the center of this gear reducer is also discussed.

New control methodology for a morphing wing demonstrator

2017 ◽  
Vol 232 (8) ◽  
pp. 1479-1494 ◽  
Author(s):  
Michel Joël Tchatchueng Kammegne ◽  
Yvan Tondji ◽  
Ruxandra Mihaela Botez ◽  
Lucian Teodor Grigorie ◽  
Mahmoud Mamou ◽  
...  
Keyword(s):  
Pressure Sensors ◽  
Open Loop ◽  
Post Processing ◽  
Pressure Data ◽  
Morphing Wing ◽  
Subsonic Wind Tunnel ◽  
Logic Control ◽  
Flexible Part ◽  
Control Methodology

A morphing wing can improve the aircraft aerodynamic performance by changing the wing airfoil depending on the flight conditions. In this paper, a new control methodology is presented for a morphing wing demonstrator tested in a subsonic wind tunnel in the open-loop configuration. Actuators integrated inside the wing are used to modify the flexible structure, which is an integral part of the wing. In this project, the actuators are made in-house and controlled with logic control, which is developed within the main frame of this work. The characterization of the flow (laminar or turbulent) over the wing is obtained starting from the pressure signals measured over the flexible part of the wing (upper surface). The signals are acquired by using some pressure sensors (Kulite sensors) incorporated in this flexible part of the wing upper surface. The technique used to collect Kulite pressure data and the post-processing methodology are explained. The recorded pressure data are sometimes subjected to noise, which is filtered before being processed. The standard deviation and power spectrum visualization of the pressure data approaches are used to evaluate the quality of the flow over the wing and estimate the transition point position in the area monitored by the Kulite sensors. In addition, infrared thermography visualization is implemented to observe the transition region over the entire wing upper surface, and to validate the methodology applied to the pressure data in this way. The demonstrator measures 1.5 m chordwise and 1.5 m spanwise. Four miniature actuators fixed on two actuation lines are used to morph the wing. The wing is also equipped with a rigid aileron. The experimental aerodynamic results obtained after post processing validate the numerical prediction for the transition location.

scholarly journals Structures of vector control of n-phase motor drives based on generalized Clarke transformation

2016 ◽  
Vol 64 (4) ◽  
pp. 865-872
Author(s):  
M. Janaszek
Keyword(s):  
Vector Control ◽  
Control Strategies ◽  
Open Loop ◽  
Current Control ◽  
Loop Current ◽  
Control Structures ◽  
Clarke Transformation ◽  
Drive Systems ◽  
Novel Concept ◽  
Multi Phase

Abstract The paper presents vector control structures for n-phase AC motors derived from generalized Clarke transformation. In contrast to known works, where authors operate on generalized formulas of the Clarke transformation, in this work, only a number of actually used phases, of mostly industrial purposes, are considered (n = 5, 6, 2×3). This allows to perform control calculations in stationary orthogonal coordinates aβ or rotating dq. There are implementations of different control strategies: ROC (rotor-oriented control) or FOC (field-oriented control). Next, the paper presents the novel concept of a voltage modulator designed for multi-phase drive systems. Operation of the modulator is based on the extended Clarke transformation for multiphase systems. A mathematical model of the multiphase voltage modulator, operating in open-loop and closed-loop current control has been presented. Some selected oscillograms of voltage and current waveform, which illustrate properties of proposed control structures have been presented.

Sign in / Sign up

Export Citation Format

Share Document