scholarly journals Design and performance assessment of an underactuated hand for industrial applications

2011 ◽  
Vol 2 (1) ◽  
pp. 9-15 ◽  
Author(s):  
C. Meijneke ◽  
G. A. Kragten ◽  
M. Wisse
Keyword(s):  
Degrees Of Freedom ◽  
International Workshop ◽  
Input Voltage ◽  
Industrial Applications ◽  
Open Loop ◽  
Robotic Hand ◽  
Loop Control ◽  
Six Degrees Of Freedom ◽  
And Performance ◽  
Underactuated Robot

Abstract. The Delft Hand 2 (DH-2) is an underactuated robot hand meant for industrial applications, having six degrees of freedom (DoF), one actuator (DoA) and no sensors. It was designed to provide a cheap and robust hand to grasp a large range of objects without damaging them. The goal of this paper is to assess the design and performance of the DH-2, demonstrating how the design was optimized for its intended application area and how the hand was simplified to make it commercially attractive. Performance tests show that the DH-2 has a payload of 2 kg for an object range of 60 to 120 mm, it can close or open within 0.5 s, and it only uses open-loop control by means of the input voltage of the motor. The results demonstrate that the industrial need of a simple, cheap and effective robotic hand can be achieved with the principle of underactuation and the use of conventional components. This paper was presented at the IFToMM/ASME International Workshop on Underactuated Grasping (UG2010), 19 August 2010, Montréal, Canada.

scholarly journals Human-Robot Interaction with Robust Prediction of Movement Intention Surpasses Manual Control

2020 ◽  
Author(s):  
Sebastijan Veselic ◽  
Claudio Zito ◽  
Dario Farina
Keyword(s):  
Degrees Of Freedom ◽  
Linear Time ◽  
Open Loop ◽  
Human Robot Interaction ◽  
Manual Control ◽  
Reach To Grasp ◽  
Robot Interaction ◽  
Loop Control ◽  
User Awareness ◽  
Improving Accuracy

Designing robotic assistance devices for manipulation tasks is challenging. This work aims at improving accuracy and usability of physical human-robot interaction (pHRI) where a user interacts with a physical robotic device (e.g., a human operated manipulator or exoskeleton) by transmitting signals which need to be interpreted by the machine. Typically these signals are used as an open-loop control, but this approach has several limitations such as low take-up and high cognitive burden for the user. In contrast, a control framework is proposed that can respond robustly and efficiently to intentions of a user by reacting proactively to their commands. The key insight is to include context- and user-awareness in the controller, improving decision making on how to assist the user. Context-awareness is achieved by creating a set of candidate grasp targets and reach-to grasp trajectories in a cluttered scene. User-awareness is implemented as a linear time-variant feedback controller (TV-LQR) over the generated trajectories to facilitate the motion towards the most likely intention of a user. The system also dynamically recovers from incorrect predictions. Experimental results in a virtual environment of two degrees of freedom control show the capability of this approach to outperform manual control. By robustly predicting the user’s intention, the proposed controller allows the subject to achieve superhuman performance in terms of accuracy and thereby usability.

Robustness of Adaptive Rotor Vibration Control to Structured Uncertainty

1997 ◽  
Vol 119 (2) ◽  
pp. 243-250 ◽  
Author(s):  
C. R. Knospe ◽  
S. M. Tamer ◽  
S. J. Fedigan
Keyword(s):  
Robustness Analysis ◽  
Stability Margin ◽  
Singular Values ◽  
Open Loop ◽  
Worst Case ◽  
Loop Control ◽  
Structured Uncertainty ◽  
Analysis Of Stability ◽  
And Performance ◽  
Performance Robustness

Recent experimental results have demonstrated the effectiveness of adaptive open-loop control algorithms for the suppression of unbalance response on rotors supported in active magnetic hearings. Herein, tools for the analysis of stability and performance robustness of this algorithm with respect to structured uncertainty are derived. The stability and performance robustness analysis problems are shown to be readily solved using a novel application of structured singular values. An example problem is presented which demonstrate the efficacy of this approach in obtaining tight bounds on stability margin and worst case performance.

scholarly journals Comprehensive Review on Main Topologies of Impedance Source Inverter Used in Electric Vehicle Applications

2020 ◽  
Vol 11 (2) ◽  
pp. 37 ◽  
Author(s):  
Daouda Mande ◽  
João Pedro Trovão ◽  
Minh Cao Ta
Keyword(s):  
Power Systems ◽  
Power Electronics ◽  
Electric Vehicles ◽  
High Efficiency ◽  
Current Source ◽  
Input Voltage ◽  
Industrial Applications ◽  
Voltage Source ◽  
Two Stage ◽  
And Performance

Power electronics play a fundamental role for electric transportation, renewable energy conversion and many other industrial applications. They have the ability to help achieve high efficiency and performance in power systems. However, traditional inverters such as voltage source and current source inverters present some limitations. Consequently, many research efforts have been focused on developing new power electronics converters suitable for many applications. Compared with the conventional two-stage inverter, Z-source inverter (ZSI) is a single-stage converter with lower design cost and high efficiency. It is a power electronics circuit of which the function is to convert DC input voltage to a symmetrical AC output voltage of desired magnitude and frequency. Recently, ZSIs have been widely used as a replacement for conventional two-stage inverters in the distributed generation systems. Several modifications have been carried out on ZSI to improve its performance and efficiency. This paper reviews the-state-of-art impedance source inverter main topologies and points out their applications for multisource electric vehicles. A concise review of main existing topologies is presented. The basic structural differences, advantages and limitations of each topology are illustrated. From this state-of-the-art review of impedance source inverters, the embedded quasi-Z-source inverter presents one of the promising architectures which can be used in multisource electric vehicles, with better performance and reliability. The utilization of this new topology will open the door to several development axes, with great impact on electric vehicles (EVs).

Paper 16: A Preliminary Investigation into the Effects of Applying a Locking Device to a Position-Controlled Externally Powered Prosthesis

1968 ◽  
Vol 183 (10) ◽  
pp. 93-97
Author(s):  
J. M. Pottinger ◽  
N. D. Ring
Keyword(s):  
Degrees Of Freedom ◽  
Position Control ◽  
Preliminary Investigation ◽  
Open Loop ◽  
Open Loop Control ◽  
Loop Control ◽  
Time Control ◽  
Dynamic Phase ◽  
Static Phase ◽  
Powered Prosthesis

The application of position control to externally powered prosthetic arms leads to increased function and versatility when compared to a prosthetic system with open-loop control. However, various compromises are necessary owing to the limited number of available control sites. An investigation is being conducted into the possibility of combining the advantages of position control during the dynamic phase of movement with the locking facility of velocity–time control during the static phase, which leads to a larger number of available control sites and thus a greater number of degrees of freedom.

Design of a Robust H∞ PID Control for Industrial Manipulators

1999 ◽  
Vol 122 (4) ◽  
pp. 803-812 ◽  
Author(s):  
Jonghoon Park ◽  
Wankyun Chung
Keyword(s):  
Pid Control ◽  
Degrees Of Freedom ◽  
Performance Tuning ◽  
Motion Controller ◽  
Six Degrees Of Freedom ◽  
Stability Robustness ◽  
Industrial Manipulators ◽  
And Performance ◽  
The Stability ◽  
L2 Gain

Industrial manipulators are under various limitations against high quality motion control; for example, both frictional and dynamic disturbances should be dealt with a simple PID control structure. A robust linear PID motion controller, called the reference error feedback (REF), is proposed, which solves the nonlinear L2-gain attenuation control problem for robotic manipulators. The stability, robustness, and performance tuning of the proposed controller are analyzed. Making use of the fact that the single parameter of the induced L2-gain γ controls the performance with stability attained, we propose a simple and stable method of performance tuning called “the square law.” The analytical results are verified through experiments of a six-degrees-of-freedom industrial manipulator. [S0022-0434(00)00104-0]

EXPERIMENTAL RESULTS FOR THE SMALL-SIGNAL STUDY OF THE PWM BOOST DC–DC CONVERTER WITH AN INTEGRAL-LEAD CONTROLLER

1995 ◽  
Vol 05 (04) ◽  
pp. 747-755 ◽  
Author(s):  
MARIAN K. KAZIMIERCZUK ◽  
ROBERT C. CRAVENS, II
Keyword(s):  
Closed Loop ◽  
Transfer Functions ◽  
Low Frequency ◽  
Input Voltage ◽  
Open Loop ◽  
Small Signal ◽  
Loop Control ◽  
Pulse Width Modulated ◽  
Bode Plots ◽  
Step Responses

An experimental verification of previously derived small-signal low-frequency open- and closed-loop characteristics and step responses of a voltage-mode-controlled pulse-width-modulated (PWM) boost DC–DC converter is presented. The Bode plots of the voltage transfer function of the control circuit, the converter and the PWM modulator, the open-loop control-to-output and input-to-output transfer functions, the loop gain, and the closed-loop control-to-output and input-to-output transfer functions are measured. The step responses to the changes in the input voltage, the duty cycle, and the reference voltage are measured. The theoretical results were in good agreement with the measured results. The small-signal model of the converter is experimentally verified.

scholarly journals The Development of a Hybrid Underwater Micro Biped Robot

2006 ◽  
Vol 3 (3) ◽  
pp. 143-150 ◽  
Author(s):  
S. Guo ◽  
Y. Okuda ◽  
W. Zhang ◽  
X. Ye ◽  
K. Asaka
Keyword(s):  
Degrees Of Freedom ◽  
Biped Robot ◽  
Input Voltage ◽  
Industrial Applications ◽  
Structure And Motion ◽  
Miniature Device ◽  
Micro Robot ◽  
Voltage Frequency ◽  
Ion Conducting ◽  
Ion Conducting Polymer

There has been a great demand, in the medical field and in industrial applications, for a novel micro biped robot with multiple degrees of freedom that can swim smoothly in water or in aqueous medium. The fish-like micro-robot studied is a type of miniature device that is installed with sensing and actuating elements. This article describes the new structure and motion mechanism of a hybrid type of underwater micro-robot using an ion-conducting polymer film (ICPF) actuator, and discusses the swimming and floating characteristics of the micro-robot in water, measured by changing the voltage frequency and the amplitude of the input voltage. Results indicate that the swimming speed of the proposed underwater micro-robot can be controlled by changing the frequency of the input voltage, and the direction (upward or downward) can be manipulated by changing the frequency of the electric current applied and the amplitude of the voltage.

Mathematical Model and Performance Evaluation for a Small Orbital Launcher

2015 ◽  
Vol 772 ◽  
pp. 388-394
Author(s):  
Teodor Viorel Chelaru ◽  
Adrian Chelaru
Keyword(s):  
Computational Model ◽  
Degrees Of Freedom ◽  
Variable Mass ◽  
Point Of View ◽  
Six Degrees Of Freedom ◽  
Model And Simulation ◽  
Multi Stage ◽  
Technical Possibility ◽  
Flight Parameters ◽  
And Performance

The purpose of this paper is to present some aspects regarding the computational model and simulation for three stage launch vehicle (LV) used to inject in orbit small size payload. The computational model consists in numerical simulation of LV evolution for imposed start conditions. The launcher model presented will be with six degrees of freedom (6DOF) and variable mass. The results analysed will be the flight parameters and ballistic performances. The discussions area will focus around the technical possibility to realize a small multi-stage launcher, end evaluate his performance using the developed model. From technical point of view, the paper is focused on ESA project “Study – concept, to achieve a Small Orbital Launcher through zonal cooperation - SOL

scholarly journals Practical Design Considerations for Performance and Robustness in the Face of Uncertain Flexible Dynamics in Space Manipulators

2021 ◽  
Vol 8 ◽  
Author(s):  
Connor Holmes
Keyword(s):  
Control Strategies ◽  
Low Frequency ◽  
Open Loop ◽  
Unmodeled Dynamics ◽  
Loop Control ◽  
Stability Margins ◽  
Flexible Mode ◽  
Space Manipulators ◽  
The Face ◽  
And Performance

Low frequency dynamics introduced by structural flexibility can result in considerable performance degradation and even instability in on-orbit, robotic manipulators. Although there is a wealth of literature that addresses this problem, the author has found that many advanced solutions are often precluded by practical considerations. On the other hand, classical, robust control methods are tractable for these systems if the design problem is properly constrained. This paper investigates a pragmatic engineering approach that evaluates the system’s stability margins in the face of uncertain, flexible perturbation dynamics with frequencies that lie close to or within the bandwidth of the nominal closed-loop system. The robustness of classical control strategies is studied in the context of both collocated (joint rate) and non-collocated (force/torque and vision-based) feedback. It is shown that robust stability and performance depend on the open-loop control bandwidth of the nominal control law (as designed for a simplified, rigid plant). Namely, the designed bandwidth must be constrained to be lower than the minimum flexible mode frequency of the unmodeled dynamics by a given factor. This strategy gives credence to popular heuristic methods commonly used to reduce the effect of unmodeled dynamics in complex manipulator systems.

Control of a Digital Micromirror Device Using Input Shaping

2007 ◽  
Author(s):  
H. Jammoussi ◽  
S. Choura ◽  
E. M. Abdel-Rahman ◽  
H. Arafat ◽  
A. Nayfeh ◽  
...  
Keyword(s):  
Electrostatic Field ◽  
Control Strategy ◽  
Nonlinear Function ◽  
Input Voltage ◽  
Open Loop ◽  
Input Shaping ◽  
Control Law ◽  
Digital Micromirror Device ◽  
Open Loop Control ◽  
Loop Control

In this paper, an open-loop control strategy is proposed for maneuvering the angular motion of a Digital Micromirror Device (DMD). The control law is based on a micromirror model that accounts for both bending and torsion motions. The model characterizes two DMD configurations: with and without contact with the substrate. The device is actuated using an electrostatic field which is a nonlinear function of the states and input voltage. The proposed control strategy is a Zero Vibration (ZV) shaper. It overshoots the DMD to its desired final angle by appropriately varying two independent input voltages. Actuating voltages and switching times are determined to maneuver the DMD from −10° to +10° tilt angles while reducing the residual vibrations.

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