A Control Method Research of Parallel Mechanisms

2012 ◽  
Vol 619 ◽  
pp. 51-55
Author(s):  
Heng Chen ◽  
Yan Bing Ni

This paper deals with a control method research and trajectory planning of parallel mechanisms. Control system scheme which is based on PC and motion controller has high openness, high degree of modularization and support for non-linear mapping relationship between operating space and joint space of parallel mechanisms with high flexibility and low cost. PC and NI motion controller and LabVIEW constituted hardware core and software platform of control system, respectively. Hardware technology of control system contained hardware selection, control circuit design and interface technology; software technology of control system developed application programs layer, core control layer and drive functions layer to realize core control functions of finding home, single-step or continuous movement and micro adjustment, which was based on hardware principle. Trajectory has been planned for a typical high speed parallel robot.

2011 ◽  
Vol 383-390 ◽  
pp. 1542-1548
Author(s):  
Zhi Bin Li

This paper describes the design and implementation of a low-cost robot control system based on a Programmable Logic Controller (PLC). The robot is a 2-DoF (Degrees of Freedom) purely translational mechanism, which has potential application in food and electronics industry for high speed pick-and-place operation. Combined with a conveyor belt, it can make 3-DoF purely translation motion. In this paper, the inverse kinematics, forward kinematics, singularity, and workspace analysis are presented. The control system architecture and software design is also introduced. The prototype is exhibited at last.


2012 ◽  
Vol 490-495 ◽  
pp. 456-459
Author(s):  
Jun Han ◽  
Rui Li Chang

Open Computer Numerical Control system (Open CNC) based on PC and the Windows operating system has been a major developing direction and a research focus of the current numerical control technology. At present, there have been all kinds of the Open CNC systems with high-speed and precision servo control boards, but they are too expensive. Therefore, developing an economical and practical motion controller is great significant for middle and small numerical control system


2011 ◽  
Vol 383-390 ◽  
pp. 79-85
Author(s):  
Dong Yuan ◽  
Xiao Jun Ma ◽  
Wei Wei

Aiming at the problems such as switch impulsion, insurmountability for influence caused by nonlinearity in one tank gun control system which adopts double PID controller to realize the multimode switch control between high speed and low speed movement, the system math model is built up; And then, Model Reference Adaptive Control (MRAC) method based on nonroutine reference model is brought in and the adaptive gun controller is designed. Consequently, the compensation of nonlinearity and multimode control are implemented. Furthermore, the Tracking Differentiator (TD) is affiliated to the front of controller in order to restrain the impulsion caused by mode switch. Finally, the validity of control method in this paper is verified by simulation.


2013 ◽  
Vol 2013 (1) ◽  
pp. 000001-000006
Author(s):  
F. Roozeboom ◽  
M. Smets ◽  
B. Kniknie ◽  
M. Hoppenbrouwers ◽  
G. Dingemans ◽  
...  

The current industrial process of choice for Deep Reactive Ion Etching (DRIE) of 3D features, e.g. Through-Silicon Vias (TSVs), Microelectromechanical Systems (MEMS), etc., is the Bosch process, which uses alternative SF6 etch cycles and C4F8-based sidewall passivation cycles in a time-sequenced mode. An alternative, potentially faster and more accurate process is to have wafers pass under spatially-divided reaction zones, which are individually separated by so-called N2-gas bearings ‘curtains’ of heights down to 10–20 μm. In addition, the feature sidewalls can be protected by replacing the C4F8-based sidewall passivation cycles by cycles forming chemisorbed and highly uniform passivation layers of Al2O3 or SiO2 deposited by Atomic Layer Deposition (ALD), also in a spatially-divided mode. ALD is performed either in thermal mode, or plasma-assisted mode in order to achieve near room-temperature processing. For metal filling of 3D-etched TSVs, or for deposition of 2D metal conductor lines one can use Laser-Induced Forward Transfer (LIFT) of metals. LIFT is a maskless, ‘solvent’-free deposition method, utilizing different types of pulsed lasers to deposit thin material (e.g. Cu, Au, Al, Cr) layers with μm-range resolution from a transparent carrier (ribbon) onto a close-by acceptor substrate. It is a dry, single-step, room temperature process in air, suitable for different types of interconnect fabrication, e.g. TSV filling and redistribution layers (RDL), without the use of wet chemistry.


Author(s):  
Guanjie Hu ◽  
Jianguo Guo ◽  
Jun Zhou

An integrated guidance and control method is investigated for interceptors with impact angle constraint against a high-speed maneuvering target. Firstly, a new control-oriented model with impact angle constraint of the integrated guidance and control system is built in the pitch plane by combining the engagement kinematics and missile dynamics model between the interceptor and target. Secondly, the flight path angle of the target is estimated by extended Kalman filter in order to transform the terminal impact angle constraint into the terminal line-of-sight angle constraint. Thirdly, a nonlinear adaptive sliding mode control law of the integrated guidance and control system is designed in order to directly obtain the rudder deflection command, which eliminates time delay caused by the traditional backstepping control method. Then the Lyapunov stability theory is used to prove the stability of the whole closed-loop integrated guidance and control system. Finally, the simulation results confirm that the integrated guidance and control method proposed in this paper can effectively improve the interception performance of the interceptor to a high-speed maneuvering target.


2012 ◽  
Vol 150 ◽  
pp. 144-147 ◽  
Author(s):  
Wei Yu Zhang ◽  
Ying Ruan ◽  
Xiao Yan Diao ◽  
Huang Qiu Zhu

To fulfil the objective of high speed, high precision and intelligence in the modern equipment and advanced manufacturing industry, the magnetic bearing is requested to have small volume, low cost and low consumption. In this paper, an AC-DC three-degree-of-freedom hybrid magnetic bearing (AC-DC-3DOF-HMB) is studied, which integrates radial bearing and axial bearing in one of the magnetic bearing. The configuration and principle of AC-DC-3DOF-HMB are expounded, and the mathematical models of suspension forces are given. Then based on the function block diagram of AC-DC-3DOF-HMB control system, its hardware and software configuration are designed. The experiment results show that the rotor can be suspended stably with three degrees of freedom and has a good performance in anti- interference, and the feasibility of the control system design can be verified.


2013 ◽  
Vol 380-384 ◽  
pp. 309-312
Author(s):  
Xue Wen Wang ◽  
Zhou Hu Deng ◽  
Xiao Yun ◽  
Long Zhang ◽  
Yuan Zhang

The mathematical vector model of a permanent magnet synchronous motor (PMSM) has first been discussed in this paper, and a servo control system based on Space Vector Pulse Width Modulation (SVPWM) has been designed, in which a enhanced Microprogrammed Control Unit (EMCU) is combined with drive chips and the relevant control software to achieve the precise control of PMSM. In order to control the position, speed and current of the PMSM, six SVPWM signals are generated with the motor vector control method, and the vector control strategy with three closed loops is projected. According to the control principle, the circuits of the hardware modules are designed and built, and the program of the control process is compiled and downloaded the EMCU, and then the human-computer interaction interface of the system is implemented by LabVIEW. The results of the test show that the control system designed can control the rotating speed and the high-speed pendulum operation of PMSM precisely.


2001 ◽  
Vol 13 (5) ◽  
pp. 554-560
Author(s):  
Doohyung Kim ◽  
◽  
Masaru Uchiyama

This paper presents the execution of very fast, complicated tasks with a high-speed accurate parallel robot we named HEXA. First, unified motion, force and compliance control scheme comprising several control algorithms are given. A key distinguishing feature of our model is control scheme, which does not use any force/torque sensors but uses the actuator backdrivability for this purpose. Hence we can ignore the weight and cost of the force/torque sensor. The motivation for this work is to show the usefulness of the versatile HEXA mechanism for applications in industry. Several experiments for complex, fast tasks, for example, the sequential peg-in-hole task on an inclined table, crank-turning, deburring and composite tasks, have been conducted using this control system to show its effectiveness.


2020 ◽  
Vol 13 (2) ◽  
pp. 156-170
Author(s):  
Bing Zhang ◽  
Saike Jiang ◽  
Ziliang Jiang ◽  
Jiandong Li ◽  
Kehong Zhou ◽  
...  

Background: The parallel mechanism is widely used in motion simulators, parallel machine tools, medical equipment and other fields. It has advantages of high rigidity, stable structure and high carrying capacity. However, the control strategy and control method are difficult to study because of the complexity of the parallel mechanism system. Objective: The purpose of this paper was to verify the dynamic model of a hydraulic driven 3-DOF parallel mechanism and propose a compound control strategy to broaden the bandwidth of the control system. Methods: The single rigid body dynamic model of the parallel mechanism was established by the Newton Euler method. The feed forward control strategy based on joint space control with inverse kinematic was designed to improve the bandwidth and control precision. The co-simulation method based on MATLAB / SIMULINK and ADAMS was adopted to verify the dynamics and control strategy. Results: The bandwidth of each degree of freedom in the 3-DOF parallel mechanism was used to expand about 10Hz and the amplitude error was controlled below 5%. Conclusion: Based on the designed dynamic model and composite control strategy, the controlled accuracy of the parallel mechanism is improved and the bandwidth of the control system is broadened. Furthermore, the improvements can be made in aspects of control accuracy and real-time performance to compose more patents on parallel mechanisms.


Actuators ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 80
Author(s):  
Shengqiao Hu ◽  
Huimin Kang ◽  
Hao Tang ◽  
Zhengjie Cui ◽  
Zhicheng Liu ◽  
...  

To improve high motion accuracy and efficiency in the high-speed operation of a 4-DOF (4 degrees of freedom) redundant parallel robot, this paper introduces a trajectory planning of the parallel robot in joint space based on the twelve-phase sine jerk motion profile. The 12-phase sine jerk motion profile utilizes the characteristics of a sine function. Furthermore, the penalty function is used to optimize the trajectory energy consumption under the constraint condition. The simulation and experimental results show that the energy consumption of joint space is slightly higher than that of the three-phase sine jerk motion profile, but the overall operation is more accurate and stable. Specifically, the sudden change of force and velocity in each joint is eliminated, which is the cause of mechanism oscillation. Moreover, the force of each joint is more average. The results indicate that each movement is closer to the maximum allowable limit and the running efficiency is higher.


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