Experiments With the Powered Arm Cobot

2004 ◽  
Author(s):  
Songho Kim ◽  
Michael Peshkin ◽  
J. Edward Colgate
Keyword(s):  
Degree Of Freedom ◽  
Experimental Results ◽  
Free Motion ◽  
Human Operator ◽  
Physical Interaction ◽  
Motion Controller ◽  
Passive Device ◽  
Direct Physical Interaction ◽  
Virtual Paths ◽  
Three Degree Of Freedom

The Arm cobot is a three degree-of-freedom manipulator intended for direct physical interaction with a human operator. The Arm cobot can operate as a passive device, such that the cobot sets the end-effector’s allowed direction of motion, while the human operator provides all motive forces. Previous work with the passive Arm cobot involved displaying free motion and virtual paths and surfaces. This paper presents experimental results with a powered Arm cobot. In one experiment, the Arm cobot is commanded to track a user-defined trajectory, while in another experiment, we show an improved free motion controller.

Development of a Human Symbiotic Assist Arm “PAS-Arm” (Experimental System and Creation of Virtual Guiding Surfaces)

2013 ◽  
Vol 25 (2) ◽  
pp. 285-293 ◽  
Author(s):  
Mineo Higuchi ◽  
◽  
Tsukasa Ogasawara ◽  
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Experimental System ◽  
Major Axis ◽  
Experimental Results ◽  
Physical Interaction ◽  
Assist Device ◽  
Two Degrees Of Freedom ◽  
Direct Physical Interaction ◽  
Continuously Variable Transmissions

We describe a new robotic assist device: the passive assist arm (PAS-Arm). PAS-Arms are intended for direct physical interaction with a human operator. PASArms are physically passive. The force to manipulate the arm end must be provided by the operator. Their purpose is not to enhance human strength, but to provide virtual guiding surfaces that constrain and guide the motion of the operator. PAS-Arms have three joints and a three dimensional workspace, but possess only two degrees of freedom due to the reduction of degrees of freedom created by a combination of Continuously Variable Transmissions (CVTs) and differential gears. In this paper, we first discuss the manipulability ellipsoid for the PAS-Arm. The major axis of the ellipsoid is the direction in which the arm end may be easily manipulated, and vice versa. We have developed an experimental system for the PAS-Arm. The CVTs of the experimental system may not adjust the transmission ratio to zero. Second, we describe an algorithm to address that problem. Finally, we present initial experiments that verify the PAS-Arm mechanism. The experimental results successfully produced virtual guiding surfaces.1 1. This paper is the full translation from the transactions of JSME, Series C, Vol.76, No.763, pp. 611-618, 2010.

Advanced Vibration Control of Atomic Force Microscope Scanner

2015 ◽  
pp. 84-106
Author(s):  
Sajal K. Das ◽  
Hemanshu R. Pota ◽  
Ian R. Petersen
Keyword(s):  
Vibration Control ◽  
Atomic Force Microscope ◽  
Atomic Level ◽  
Degree Of Freedom ◽  
Experimental Results ◽  
Surface Imaging ◽  
Atomic Force Microscopes ◽  
Atomic Force ◽  
Three Degree Of Freedom ◽  
Damping Controller

Atomic Force Microscopes (AFMs) are used in many nanopositioning applications in order to measure the topography of various specimens at an atomic level through surface imaging. The imaging of the samples in AFMs is carried out by using a three degree-of-freedom positioning unit called Piezoelectric Tube Scanner (PTS). The performance of the AFM mostly depends on the performance of the PTS. However, the PTS of the AFM suffers from the problem of vibration. This chapter presents a design of a damping controller to compensate the induced vibration of the scanner. Experimental results are presented to show the effectiveness of the proposed controller. The experimental results show that the proposed controller is able to compensate 90% of the vibration of the PTS.

Brake Squeal Noise Due to Disk Misalignment

2005 ◽  
Author(s):  
Yeon-Sun Choi ◽  
Ju-Pyo Park
Keyword(s):  
Stability Analysis ◽  
Degree Of Freedom ◽  
Experimental Results ◽  
Brake System ◽  
Nonlinear Friction ◽  
Brake Squeal ◽  
Friction Characteristic ◽  
Brake Dynamometer ◽  
Three Degree Of Freedom ◽  
Squeal Noise

To understand brake squeal noise, the sound and vibration of an automobile brake system were measured using a brake dynamometer. The experimental results show that an important factor in squeal generation is the run-out due to disk misalignment. A three-degree of freedom model is developed for the brake system, where the run-out effect and nonlinear friction characteristic are included. A stability analysis of the model was also performed to predict the generation of squeal with the modification of the brake system. The results show that squeal generation is dependant on the run-out rather than the friction characteristic between pad and disk.

scholarly journals Development of a Compound Speckle Interferometer for Precision Three-Degree-of-Freedom Displacement Measurement

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1828
Author(s):  
Hung-Lin Hsieh ◽  
Bo-Yen Sun
Keyword(s):  
Speckle Interferometry ◽  
Degree Of Freedom ◽  
Heterodyne Interferometry ◽  
Beam Splitting ◽  
Speckle Interferometer ◽  
Real World Applications ◽  
Three Degree Of Freedom ◽  
Contact Displacement ◽  
Displacement Measurements ◽  
Measurement Capabilities

In this study, a compound speckle interferometer for measuring three-degree-of-freedom (3-DOF) displacement is proposed. The system, which combines heterodyne interferometry, speckle interferometry and beam splitting techniques, can perform precision 3-DOF displacement measurements, while still having the advantages of high resolution and a relatively simple configuration. The incorporation of speckle interferometry allows for non-contact displacement measurements by detecting the phase of the speckle interference pattern formed from the convergence of laser beams on the measured rough surface. Experiments were conducted to verify the measurement capabilities of the system, and the results show that the proposed system has excellent measurement capabilities suitable for future real-world applications.

scholarly journals Analytical Investigation on Torque of Three-Degree-of-Freedom Electromagnetic Actuator for Image Stabilization

2021 ◽  
Vol 11 (15) ◽  
pp. 6872
Author(s):  
Chien-Sheng Liu ◽  
Yi-Hsuan Lin ◽  
Chiu-Nung Yeh
Keyword(s):  
Power Efficiency ◽  
Rotation Angle ◽  
Analytical Investigation ◽  
Degree Of Freedom ◽  
Electromagnetic Actuator ◽  
3D Fem ◽  
Image Stabilization ◽  
Large Rotation ◽  
Spherical Motor ◽  
Three Degree Of Freedom

In keeping with consumers’ preferences for electromagnetic motors of ever smaller power consumption, it is necessary to improve the power efficiency of the electromagnetic motors used in unmanned aerial vehicles and robots without sacrificing their performance. Three-degree-of-freedom (3-DOF) spherical motors have been developed for these applications. Accordingly, this study modifies the 3-DOF spherical motor proposed by Hirata’s group in a previous study (Heya, A.; Hirata, K.; Niguchi, N., Dynamic modeling and control of three-degree-of-freedom electromagnetic actuator for image stabilization, IEEE Transactions on Magnetics 2018, 54, 8207905.) to accomplish a 3-DOF spherical motor for camera module with higher torque output in the large rotation angle. The main contribution of this study is to improve the static torque in the X- and Y-axes with an improved electromagnetic structure and a particular controlling strategy. In the structural design, eight symmetrical coils with specific coil combination are used instead of conventional four symmetrical coils. In this study, the development of the proposed 3-DOF spherical motor was constructed and verified by using a 3D finite-element method (3D FEM). The simulation results show that the proposed 3-DOF spherical motor has higher torque output in the large rotation angle when compared to the original 3-DOF spherical motor.

Three-Degree-of-Freedom Parallel Robot Arm

2006 ◽  
Author(s):  
Martin Hosek ◽  
Michael Valasek ◽  
Jairo Moura
Keyword(s):  
Parallel Robot ◽  
Degree Of Freedom ◽  
Motion Path ◽  
Angular Orientation ◽  
Robot Arm ◽  
Flat Panel Display ◽  
End Effector ◽  
Cluster Tools ◽  
Manufacturing Applications ◽  
Three Degree Of Freedom

This paper presents single- and dual-end-effector configurations of a planar three-degree of freedom parallel robot arm designed for automated pick-place operations in vacuum cluster tools for semiconductor and flat-panel-display manufacturing applications. The basic single end-effector configuration of the arm consists of a pivoting base platform, two elbow platforms and a wrist platform, which are connected through two symmetric pairs of parallelogram mechanisms. The wrist platform carries an end-effector, the position and angular orientation of which can be controlled independently by three motors located at the base of the robot. The joints and links of the mechanism are arranged in a unique geometric configuration which provides a sufficient range of motion for typical vacuum cluster tools. The geometric properties of the mechanism are further optimized for a given motion path of the robot. In addition to the basic symmetric single end-effector configuration, an asymmetric costeffective version of the mechanism is derived, and two dual-end-effector alternatives for improved throughput performance are described. In contrast to prior attempts to control angular orientation of the end-effector(s) of the conventional arms employed currently in vacuum cluster tools, all of the motors that drive the arm can be located at the stationary base of the robot with no need for joint actuators carried by the arm or complicated belt arrangements running through the arm. As a result, the motors do not contribute to the mass and inertia properties of the moving parts of the arm, no power and signal wires through the arm are necessary, the reliability and maintenance aspects of operation are improved, and the level of undesirable particle generation is reduced. This is particularly beneficial for high-throughput applications in vacuum and particlesensitive environments.

Kinematics of a New High-Precision Three-Degree-of-Freedom Parallel Manipulator

2006 ◽  
Vol 129 (3) ◽  
pp. 320-325 ◽  
Author(s):  
Farhad Tahmasebi
Keyword(s):  
Power Dissipation ◽  
Inverse Kinematics ◽  
Parallel Manipulator ◽  
Degree Of Freedom ◽  
Base Plane ◽  
Degree Polynomial ◽  
Payload Capacity ◽  
Half Angle ◽  
Three Degree Of Freedom ◽  
Direct Kinematics

Closed-form direct and inverse kinematics of a new three-degree-of-freedom (DOF) parallel manipulator with inextensible limbs and base-mounted actuators are presented. The manipulator has higher resolution and precision than the existing three-DOF mechanisms with extensible limbs. Since all of the manipulator actuators are base mounted, higher payload capacity, smaller actuator sizes, and lower power dissipation can be obtained. The manipulator is suitable for alignment applications where only tip, tilt, and piston motions are significant. The direct kinematics of the manipulator is reduced to solving an eighth-degree polynomial in the square of the tangent of the half-angle between one of the limbs and the base plane. Hence, there are at most 16 assembly configurations for the manipulator. In addition, it is shown that the 16 solutions are eight pairs of reflected configurations with respect to the base plane. Numerical examples for the direct and inverse kinematics of the manipulator are also presented.

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