ANALYSIS OF THE SPEED OF THE DEFUZZIFIER IN THE TASK OF CONTROLLING THE ROBOT-MANIPULATOR

2020 ◽  
pp. 18-28
Author(s):  
M. V. Bobyr ◽  
N. A. Milostnaya ◽  
A. E. Arkhipov ◽  
M. Yu. Luneva
Keyword(s):  
Simulation Model ◽  
Digital Filter ◽  
High Speed ◽  
Robot Manipulator ◽  
Computation Time ◽  
Robotic Manipulator ◽  
Center Of Gravity ◽  
Robotic Arm ◽  
Ratio Method ◽  
Gravity Method

Linear, nonlinear, modified, high-speed defuzzifiers based on the area ratio method are presented in this paper. The proposed defuzzifiers are used in a fuzzy digital filter device and make it possible to ensure the additivity of the robotic manipulator control system, since traditional models do not have this property. The essence of this development is to find a crisp value of the output fuzzy variable, which in this case are the regulation coefficients of the fuzzy digital filter. Reducing the number of computational operations provides an increase in the performance of the defuzzifier. The reduction in number of computational operations is carried out by eliminating the output variable’s truncated term’s height calculation, thereby reducing the computation time. A simulation model which was implemented in the MatLab Simulink system, for a neuro-fuzzy device of the robotic arm using linear and non-linear defuzzifiers is presented. The dependence of time graphs on the angle of rotation of the joints of the robotic manipulator are compared, based on the traditional center of gravity method and the method shown in this paper. It was found that the traditional center of gravity method does not ensure the fulfillment of the specified rotation angles of the links of the robotic arm, while the proposed models of defuzzifiers have this property, which can be seen from the presented dependency graphs. The simulation model of the device was also designed as a parallel-conveyor device for implementation in the field-programmable gate array of the Xilinx Spartan 3Е family. The analysis showed that the calculation time for a crisp value with high-speed defuzzification is 130 ns, which is two orders of magnitude higher than existing models. The experiment was conducted at a frequency of 100 MHz.

scholarly journals Filtering a Signal in a Fuzzy Filter Based on the Area Ratio Method

2020 ◽  
Vol 24 (3) ◽  
pp. 183-195
Author(s):  
M. V. Bobyr ◽  
M. Yu. Luneva
Keyword(s):  
Kalman Filter ◽  
Digital Filter ◽  
Experimental Studies ◽  
Area Ratio ◽  
Center Of Gravity ◽  
Ratio Method ◽  
Fuzzy Filter ◽  
Signal Filtering ◽  
Gravity Method ◽  
Control Coefficients

Purpose of reseach. Digital signal filtering allows real-time noise reduction in electronic devices. Currently, there are many different digital filters, differing in speed, computing power, algorithms and restrictions on the conditions of use. One of these filters is the Kalman filter, but adjusting the gains of this filter is very complicated by the process of additional experiments and collection of statistical information. Therefore, in this paper, the authors consider a simplified algorithm for finding the control coefficients of a fuzzy digital filter with defuzzifier based on the area ratio method and investigate the influence of the area ratio method parameters on signal filtering, thereby achieving the goal of improving the accuracy of the fuzzy digital filter. Methods. For the algorithm for finding the control coefficients of the digital filter, a fuzzy logic apparatus was used. The control factors are determined using a defuzzifier based on the area ratio method. Results. In the course of experimental studies, the mean square error RMSE was calculated for a fuzzy digital filter using the area ratio method, the center of gravity method and the Kalman filter. Based on the results obtained, it was concluded that the fuzzy filter based on the area ratio RMSE method is 5.43 times less than for the Kalman filter and 2.77 times less than for the defuzzifier based on the center of gravity method. The results obtained prove the effectiveness of using a fuzzy digital filter with the area ratio method. Conclusion: This article considers an algorithm for the operation of a fuzzy digital filter, simulates a fuzzy digital filter and a Kalman filter in the Simulink system and calculates the RMSE values for a fuzzy digital filter with the area ratio method and the center of gravity method, as well as the Kalman filter.

FPGA-based hardware implementation of arctangent and arccosine functions for the inverse kinematics of robot manipulator

2014 ◽  
Vol 31 (8) ◽  
pp. 1679-1690 ◽  
Author(s):  
Ying-Shieh Kung ◽  
Ming-Kuang Wu ◽  
Hai Linh Bui Thi and ◽  
Tz-Han Jung ◽  
Feng-Chi Lee ◽  
...  
Keyword(s):  
Taylor Series ◽  
Inverse Kinematics ◽  
High Speed ◽  
Robot Manipulator ◽  
Processing System ◽  
Computation Time ◽  
Taylor Series Expansion ◽  
Polynomial Form ◽  
Content Type ◽  
Speed Up

Purpose – The inverse kinematics in robot manipulator have to handle the arctangent and arccosine function. However, the two functions are complicated and need much computation time so that it is difficult to be realized in the typical processing system. The purpose of this paper is to solve this problem by using Field Programmable Gate Array (FPGA) to speed up the computation power. Design/methodology/approach – The Taylor series expansion method is firstly applied to transfer arctangent and arccosine function to a polynomial form. And Look-Up Table (LUT) is used to store the parameters of the polynomial form. Then the behavior of the computation algorithm is described by Very high-speed IC Hardware Description Language (VHDL) and a co-simulation using ModelSim and Simulink is applied to evaluate the correctness of the VHDL code. Findings – The computation time of arctangent and arccosine function using by FPGA need only 320 and 420 ns, respectively, and the accuracy is <0.01°. Practical implications – Fast computation in arctangent and arccosine function can speed up the motion response of the real robot system when it needs to perform the inverse kinematics function. Originality/value – This is the first time such to combine the Taylor series method and LUT method in the computation the arctangent and arccosine function as well as to implement it with FPGA.

Efficient Computing in Image Processing and DSPs with ASIP Based Multiplier

2019 ◽  
Vol 13 (2) ◽  
pp. 174-180
Author(s):  
Poonam Sharma ◽  
Ashwani Kumar Dubey ◽  
Ayush Goyal
Keyword(s):  
Image Processing ◽  
High Speed ◽  
Computation Time ◽  
Digital Signal ◽  
Instruction Set ◽  
Computationally Efficient ◽  
Specific Instruction ◽  
Processor Core ◽  
Speed Performance ◽  
Application Specific

Background: With the growing demand of image processing and the use of Digital Signal Processors (DSP), the efficiency of the Multipliers and Accumulators has become a bottleneck to get through. We revised a few patents on an Application Specific Instruction Set Processor (ASIP), where the design considerations are proposed for application-specific computing in an efficient way to enhance the throughput. Objective: The study aims to develop and analyze a computationally efficient method to optimize the speed performance of MAC. Methods: The work presented here proposes the design of an Application Specific Instruction Set Processor, exploiting a Multiplier Accumulator integrated as the dedicated hardware. This MAC is optimized for high-speed performance and is the application-specific part of the processor; here it can be the DSP block of an image processor while a 16-bit Reduced Instruction Set Computer (RISC) processor core gives the flexibility to the design for any computing. The design was emulated on a Xilinx Field Programmable Gate Array (FPGA) and tested for various real-time computing. Results: The synthesis of the hardware logic on FPGA tools gave the operating frequencies of the legacy methods and the proposed method, the simulation of the logic verified the functionality. Conclusion: With the proposed method, a significant improvement of 16% increase in throughput has been observed for 256 steps iterations of multiplier and accumulators on an 8-bit sample data. Such an improvement can help in reducing the computation time in many digital signal processing applications where multiplication and addition are done iteratively.

scholarly journals Method for Robot Manipulator Joint Wear Reduction by Finding the Optimal Robot Placement in a Robotic Cell

2021 ◽  
Vol 11 (12) ◽  
pp. 5398
Author(s):  
Tomáš Kot ◽  
Zdenko Bobovský ◽  
Aleš Vysocký ◽  
Václav Krys ◽  
Jakub Šafařík ◽  
...  
Keyword(s):  
Angular Velocity ◽  
Dynamic Simulation ◽  
Robot Manipulator ◽  
The Other ◽  
Robotic Arm ◽  
Robotic Cell ◽  
Wear Reduction ◽  
Fixed End ◽  
Robot Placement ◽  
Collaborative Robot

We describe a method for robotic cell optimization by changing the placement of the robot manipulator within the cell in applications with a fixed end-point trajectory. The goal is to reduce the overall robot joint wear and to prevent uneven joint wear when one or several joints are stressed more than the other joints. Joint wear is approximated by calculating the integral of the mechanical work of each joint during the whole trajectory, which depends on the joint angular velocity and torque. The method relies on using a dynamic simulation for the evaluation of the torques and velocities in robot joints for individual robot positions. Verification of the method was performed using CoppeliaSim and a laboratory robotic cell with the collaborative robot UR3. The results confirmed that, with proper robot base placement, the overall wear of the joints of a robotic arm could be reduced from 22% to 53% depending on the trajectory.

scholarly journals Influence of tool edge form factor and cutting parameters on milling performance

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110090
Author(s):  
Xuefeng Zhao ◽  
Hao Qin ◽  
Zhiguo Feng
Keyword(s):  
Form Factor ◽  
Simulation Model ◽  
Cutting Force ◽  
Surface Quality ◽  
High Speed ◽  
Orthogonal Cutting ◽  
Cutting Temperature ◽  
Tool Edge ◽  
Drag Finishing ◽  
Edge Preparation

Tool edge preparation can improve the tool life, as well as cutting performance and machined surface quality, meeting the requirements of high-speed and high-efficiency cutting. In general, prepared tool edges could be divided into symmetric or asymmetric edges. In the present study, the cemented carbide tools were initially edge prepared through drag finishing. The simulation model of the carbide cemented tool milling steel was established through Deform software. Effects of edge form factor, spindle speed, feed per tooth, axial, and radial cutting depth on the cutting force, the tool wear, the cutting temperature, and the surface quality were investigated through the orthogonal cutting simulation. The simulated cutting force results were compared to the results obtained from the orthogonal milling experiment through the dynamometer Kistler, which verified the simulation model correctness. The obtained results provided a basis for edge preparation effect along with high-speed and high effective cutting machining comprehension.

Simulation on the Regulating Characteristics of the Pulse Modulation Hydraulic Hammer

2011 ◽  
Vol 422 ◽  
pp. 176-183
Author(s):  
Gang Wang ◽  
Yu Wan Cen
Keyword(s):  
Time Delay ◽  
Simulation Model ◽  
Impact Energy ◽  
High Speed ◽  
Impact Frequency ◽  
Pulse Modulation ◽  
Motion Equations ◽  
Hydraulic Hammer ◽  
Working Frequency ◽  
Simulation Results

To improve the regulating characteristics of impact energy, simplify structure of hydraulic hammer, a new pulse modulation hydraulic hammer is presented in the paper which can help regulate its impact frequency easily. The motion equations of the hydraulic hammer are established, its simulation model is obtained and the dynamic simulation is carried out on AMESim. The dynamics of high-speed ON/OFF valve is taken into account in the simulation model. The tendency of simulation results conforms to experimental results; it shows that the pulse modulation hydraulic hammer is feasible, and the hydraulic hammer model is reasonable. The time delay in high working frequency is also analyzed.

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