Precision-limit positioning of direct drive systems with the existence of friction

2003 ◽  
Vol 11 (3) ◽  
pp. 233-244 ◽  
Author(s):  
Ting-Yung Lin ◽  
Yih-Chieh Pan ◽  
Chen Hsieh
Keyword(s):  
Direct Drive ◽  
Precision Limit ◽  
Drive Systems

PRECISION-LIMIT POSITIONING OF DIRECT DRIVE SYSTEMS WITH THE EXISTENCE OF FRICTION

2002 ◽  
Vol 35 (1) ◽  
pp. 293-298
Author(s):  
T.–Y. Lin ◽  
Y.-C. Pan ◽  
C. Hsieh
Keyword(s):  
Direct Drive ◽  
Precision Limit ◽  
Drive Systems

Analytical Modeling and Experimental Validation of Force Ripple and Friction Force for General Direct Drive Systems

2013 ◽  
Author(s):  
Ran Zhao ◽  
Chengying Xu
Keyword(s):  
Analytical Modeling ◽  
Tracking Error ◽  
Least Square Method ◽  
Optimization Methods ◽  
Analytical Form ◽  
Least Square ◽  
Direct Drive ◽  
Drive Systems ◽  
Force Ripple ◽  
Engineering Practices

In this paper, we present a systematic modeling method of direct drive systems. Experiments are designed to decouple and model friction and force ripple separately, which are two major sources of tracking error. Three different optimization methods, least square method, nonlinear least square method and particle swarm optimization are used for parameter optimization. The analytical form of the model makes it easy to use in engineering practices. All results are obtained and verified experimentally. The method presented in this paper can also be used to model other mechanical systems.

scholarly journals Control of a Direct-Drive Arm

1983 ◽  
Vol 105 (3) ◽  
pp. 136-142 ◽  
Author(s):  
H. Asada ◽  
T. Kanade ◽  
I. Takeyama
Keyword(s):  
Drive System ◽  
Direct Drive ◽  
Excellent Performance ◽  
Mechanical Stiffness ◽  
Feedback Controllers ◽  
Transmission Mechanisms ◽  
Single Link ◽  
High Torque ◽  
Drive Systems ◽  
Speed And Accuracy

A direct-drive arm is a mechanical arm in which the shafts of articulated joints are directly coupled to the rotors of motors with high torque. Since the arm does not contain transmission mechanisms between the motors and their loads, the drive system has no backlash, small friction, and high mechanical stiffness, all of which are desirable for fast, accurate, and versatile robots. First, the prototype robot is described, and basic feedback controllers for single-link drive systems are designed. Second, feedforward compensation is discussed. This compensation significantly reduces the effect of interactions among multiple joints and nonlinear forces. The experiments showed the excellent performance of the direct-drive arm in terms of speed and accuracy.

scholarly journals Method for holistic wind turbine drivetrain comparison exemplarily applied to geared and direct drive systems

2021 ◽  
Author(s):  
Freia Harzendorf ◽  
Ralf Schelenz ◽  
Georg Jacobs
Keyword(s):  
Wind Turbine ◽  
Meta Analysis ◽  
Design Stage ◽  
Target System ◽  
Strong Wind ◽  
Direct Drive ◽  
Early Design ◽  
Early Design Stage ◽  
Evaluation Approach ◽  
Drive Systems

AbstractThe drivetrain as an important part of wind turbines needs to be improved in order to deal with today’s high development and cost pressure. One important step towards enhanced drivetrains is to identify the most suitable concept for a targeted onshore application in an early design stage. With this purpose, a holistic lifecycle system evaluation approach relying on minimum input information is presented. In order to identify a dominant solution, an additive target system is defined taking cost, ecological sustainability, and supplied energy into account. This multi-criteria decision is aggregated by defining a macrosocial evaluation criterion: “drivetrain specific energy supply effort”. A physics- and empirically-based model is developed to quantify the targets for different onshore drivetrain concepts. The validity of the model results is shown by a comparison to meta-analysis findings. Being utilized on a drivetrain concept comparison between geared and direct drive the approach’s value is showcased. Both concepts score on a comparable level slightly differing in weak and strong wind regimes. An exemplary trade-off between investment- and operational effort shows, that for both concepts the investment effort is higher than the operational. The comparison furthermore shows how robust decision support can be provided by parameter variation and finally it stresses, that the decision maker’s preferences need to be incorporated in the decision. Concluding, this analysis shows that physics- and empirically-based model approaches enable holistic wind turbine drivetrain concept comparisons in an early design stage.

Disturbance Observers for Rigid Mechanical Systems: Equivalence, Stability, and Design

2002 ◽  
Vol 124 (4) ◽  
pp. 539-548 ◽  
Author(s):  
Erwin Schrijver ◽  
Johannes van Dijk
Keyword(s):  
Disturbance Rejection ◽  
Disturbance Observer ◽  
High Speed ◽  
Design Procedure ◽  
Systematic Design ◽  
Direct Drive ◽  
Robot Tracking ◽  
Feedback Structure ◽  
Drive Systems ◽  
The One

Mechanical (direct-drive) systems designed for high-speed and high-accuracy applications require control systems that eliminate the influence of disturbances like cogging forces and friction. One way to achieve additional disturbance rejection is to extend the usual (P(I)D) controller with a disturbance observer. There are two distinct ways to design, represent, and implement a disturbance observer, but in this paper it is shown that the one is a generalization of the other. A general systematic design procedure for disturbance observers that incorporates stability requirements is given. Furthermore, it is shown that a disturbance observer can be transformed into a classical feedback structure, enabling numerous well-known tools to be used for the design and analysis of disturbance observers. Using this feedback interpretation of disturbance observers, it will be shown that a disturbance observer based robot tracking controller can be constructed that is equivalent to a passivity based controller. By this equivalence not only stability proofs of the disturbance observer based controller are obtained, but it also provides more transparent controller parameter selection rules for the passivity based controller.

Non-Newtonian Fluid Cavern and Newtonian Cloud Height Tests to Characterize Pulse Jet Mixer Operation

2011 ◽  
Author(s):  
Carl W. Enderlin ◽  
Jagannadha R. Bontha ◽  
Judith Ann Bamberger ◽  
Franz Nigl
Keyword(s):  
Steady State ◽  
Yield Stress ◽  
Newtonian Fluid ◽  
Treatment Plant ◽  
Test System ◽  
Direct Drive ◽  
Cloud Height ◽  
Jet Velocity ◽  
Drive Systems ◽  
Pulse Jet

Pulse jet mixing systems are being developed for use in the Waste Treatment Plant in Washington State. To assist with system development, scaled tests were conducted to obtain experimental measurements of the cloud height for Newtonian slurries and cavern heights for a Non-Newtonian yield stress material. The measurements were required to assess the effective mixing and material mobilization produced during pulse jet mixer operation. The cloud height measurements were obtained for a single steady-state jet directed downward in a spherical-bottom tank. The cloud tests used glass beads in water to evaluate the height of the suspended slurry as a function of jet velocity. Cloud testing revealed that the glass bead material was suspended in the tank quickly and developed a distinctive height for each combination of flow rate and particulate size tested. The solids loading had minimal impact on the cloud height for a given particle size. During all cloud tests, the surface of the tank remained relatively calm, indicating that the slurry was dissipating the mixing energy of the relatively high velocity jet. Cavern tests were conducted to obtain experimental data of non-Newtonian fluid mixing for fluid properties similar to those of certain tank wastes. A transparent material that exhibited a yield stress and shear thinning behavior was used to obtain measurements of steady-state cavern heights as a function of jet velocity. For the non-Newtonian fluid cavern tests, distinct cavern volumes were readily developed for the four velocities tested. A linear relationship was observed to exist between cavern height and nozzle velocity. Since the experimental work detailed in this paper was completed, additional scaled tests have been conducted with pneumatic drive systems and direct drive systems similar to that described for this effort. Data from both types of measurements are shown to be linear; however, effects from the reciprocating drive systems that are not yet incorporated into models may be affecting the ability to collapse this data independent of scale. It is recommended that future efforts to assess performance of PJM operations using scaled tests consider employing direct drive systems to aid in evaluating scaling trends. A test system can be configured to allow testing at both reciprocating and direct drive conditions; thereby allowing direct comparison between them.

scholarly journals A Review of Transverse Flux Machines Topologies and Design

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7173
Author(s):  
Víctor Ballestín-Bernad ◽  
Jesús Sergio Artal-Sevil ◽  
José Antonio Domínguez-Navarro
Keyword(s):  
Power Systems ◽  
Prime Mover ◽  
Variable Speed ◽  
Direct Drive ◽  
Comprehensive Review ◽  
Potential Applications ◽  
High Torque ◽  
Transverse Flux ◽  
Drive Systems ◽  
Load Variable

High torque and power density are unique merits of transverse flux machines (TFMs). TFMs are particularly suitable for use in direct-drive systems, that is, those power systems with no gearbox between the electric machine and the prime mover or load. Variable speed wind turbines and in-wheel traction seem to be great-potential applications for TFMs. Nevertheless, the cogging torque, efficiency, power factor and manufacturing of TFMs should still be improved. In this paper, a comprehensive review of TFMs topologies and design is made, dealing with TFM applications, topologies, operation, design and modeling.

Application of Integrated Electronic Control on Gas Turbine Marine Direct Drive Propulsion

1999 ◽  
Author(s):  
Gregory L. Murphy
Keyword(s):  
Gas Turbine ◽  
Digital Control ◽  
Water Jet ◽  
Control Technology ◽  
Electronic Control ◽  
Direct Drive ◽  
Drive Systems ◽  
Marine Applications

The use of digital controls in marine gas turbine propulsion has not been as widespread as in other applications. Although these controls have been used in marine applications such as gas turbine electric and water jet drive systems, digital controls have not been applied to a gas turbine direct drive application. This paper describes the use of digital control technology in a marine direct drive application.

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