Mechanics performance of three-degree-of-freedom excavating mechanism of an electric shovel

Author(s):  
B Wei ◽  
F Gao ◽  
J Chen ◽  
J He ◽  
S Wu ◽  
...  

Electric shovel is one of the most important equipment in surface-mining operations. The medium–tool interaction model is an essential basis in the process of machine design. Therefore, it is important to make the model accurate compared to the actual situation. This article proposes a new medium–tool interaction model based on the analysis of medium–tool interaction mechanism taking into account the actual excavating process. The result of the new model is quite in agreement with the full-scale tests. In order to make the excavating process more efficient, the traditional two-degree-of-freedom (DOF) excavating mechanism is redesigned and a new three-DOF excavating mechanism is obtained. A new electric shovel with three-DOF excavating mechanism is more flexible in that it will perform the excavation process with a favourable excavating angle that can reduce the resistance force involved in medium–tool interaction. Based on the new medium–tool interaction model, the dynamic model of the three-DOF excavating mechanism is established for the mechanics performance analysis. The numeric validation shows that the new excavating mechanism is more efficient in the excavating process.

Author(s):  
A.F. Klebanov ◽  
M.V. Kadochnikov ◽  
V.V. Ulitin ◽  
D.N. Sizemov

The article addresses the issues of ensuring safe operation of mining equipment in surface mining. It describes the main factors and situations that pose a high risk to human life and health. The most dangerous incidents are shown to be related to limited visibility and blind spots for operators of mining equipment, which can result in collisions and personnel run over. The main technologies and specific solutions used to design collision avoidance systems are described and their general comparison is provided. A particular focus is placed on monitoring the health of employees at their workplace by means of portable personal devices that promptly inform the dispatcher of emergency situations. General technical requirements are formulated for designing of the system to prevent equipment collisions and personnel run over in surface mining operations. The paper emphasizes the importance of introducing a multifunctional safety system in surface mines in order to minimise the possibility of incidents and accidents throughout the entire production cycle.


2018 ◽  
Vol 138 (2/2018) ◽  
pp. 84-89
Author(s):  
K.Yu. Anistratov ◽  
T.V. Donchenko ◽  
P.I. Opanasenko ◽  
I.B. Strogiy

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1828
Author(s):  
Hung-Lin Hsieh ◽  
Bo-Yen Sun

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.


2021 ◽  
Vol 11 (15) ◽  
pp. 6872
Author(s):  
Chien-Sheng Liu ◽  
Yi-Hsuan Lin ◽  
Chiu-Nung Yeh

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.


Author(s):  
Martin Hosek ◽  
Michael Valasek ◽  
Jairo Moura

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.


2006 ◽  
Vol 129 (3) ◽  
pp. 320-325 ◽  
Author(s):  
Farhad Tahmasebi

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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