Mathematical model of robotic assembly by means of adaptation and low-frequency vibration

2017 ◽  
Vol 37 (1) ◽  
pp. 130-134 ◽  
Author(s):  
Michael V. Vartanov ◽  
Leonarda V. Bojkova ◽  
Inna N. Zinina

Purpose The purpose of this paper is to define the conditions for a failsafe coupling of parts when using adaptation and low-frequency vibrations. A model enables us to determine the reaction at the contact points of parts and time-based contact conditions changes. Therefore, the conditions of jamming parts can be defined in the process of conjugation. Design/methodology/approach A mathematical model describing the trajectory of the part mass center in robotic assembly is created. An experimental equipment is also presented in the paper. Convergence of theoretical and experimental results that characterize the reliability of processes is estimated. Findings The mathematical model of the connection process dynamics is found in the form of Lagrange’s equations of the second kind. Originality/value Applying low-frequency vibration and the adaptive gripper is proposed to extend technological capabilities of robotic assembly.

2018 ◽  
Vol 38 (3) ◽  
pp. 314-322 ◽  
Author(s):  
Shi-qing Wu ◽  
Bin Shen ◽  
Yun-zhe Tang ◽  
Jia-hai Wang ◽  
Da-teng Zheng

Purpose The purpose of this paper is to study a method to optimize the arrangement of the devices on a smart assembly workbench, which help to reduce fatigue and improve efficiency for the worker. Design/methodology/approach The optimization priority is studied based on the users’ decisions, a mathematical model of the layout optimization is established from ergonomic perspective and an improved algorithm is adopted to solve the built the mathematical model. Findings Ergonomic software Jack is chosen to simulate the four layout schemes obtained. Through comparative analysis of the simulation results, it is proven that the optimal solution can be obtained using the improved algorithm. Originality/value The mathematical model built on observation comfort, operation comfort and device accessibility, as well as the improved algorithm in this paper, has some reference values for the layout design of smart assembly workbench.


Circuit World ◽  
2019 ◽  
Vol 45 (4) ◽  
pp. 231-256
Author(s):  
JiaRong Wang ◽  
XiaoQiang Chen

Purpose This paper aims to obtain a symmetrical step-down topology with lower equivalent capacity and wider step-down range under the condition of the same output. Three new symmetrical step-down topologies of zigzag autotransformer are proposed in this paper. Taking the equivalent capacity as the main parameter, the obtained topologies are modeled and analyzed in detail. Design/methodology/approach This paper adopts the research methods of design, modeling, analysis and simulation verification. First, the zigzag autotransformer is redesigned according to the design objective of symmetrical step-down topology. Second, the mathematical model of the designed topology is established, and the detailed theoretical analysis is carried out. Finally, the theoretical results are verified by simulation. Findings Three symmetrical zigzag autotransformer step-down topologies are designed, the winding configurations of the corresponding topology are presented, the step-down ranges of these three topologies are calculated and the influence of step-down ratio on equivalent capacity of autotransformer is analyzed. Through analysis, the target step-down topologies are obtained when the step-down ratio is [0.969, 1.414] and [1.414, 8]. Research limitations/implications Because the selected research object is only zigzag autotransformer, the research results may lack generality. Therefore, researchers are encouraged to further study topologies of other autotransformers. Practical implications This paper includes the implications of step-down ratio on the equivalent capacity of autotransformer and the configuration of transformer windings. Originality/value The topologies designed in this paper enable zigzag autotransformer to be applied in step-down circumstances.


2011 ◽  
Vol 31 (4) ◽  
pp. 358-362 ◽  
Author(s):  
Ryspek Usubamatov ◽  
K.W. Leong

PurposeThe purpose of this paper is to investigate theoretically the process of jamming in the peg‐hole type parts and to derive a mathematical model of jamming.Design/methodology/approachThe mathematical model of the jamming of the peg‐hole type parts in assembly process was performed and its boundary conditions, which lead to jamming, defined.FindingsThe equation of the critical angles of declination for the peg, which leads to the peg‐hole jam, was derived. The boundary condition of the angles of declination and the depth of the peg insertion into the hole were defined.Research limitations/implicationsA mathematical model is developed for rigid parts with a hole and for the peg clamped in the rigid assembly mechanisms. The research has not considered flexible deformations and stiffness of the assembly mechanisms, which result in the peg's declination in the assembly process.Practical implicationsThe results are represented in the form of the peg's critical angles of declination and critical depth of insertion into the hole, which leads to jamming of the peg‐hole type parts to be assembled. On the basis of the obtained results, it is possible to formulate the tolerances of the declination angles for the assembly mechanisms, which clamp the peg‐type parts.Originality/valueThe proposed method calculating the critical angles of the peg's declination and critical depth of the peg's insertion into the hole for assembly of the peg‐hole type parts, enables one to increase the reliability of the assembly process in the manufacturing industry.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shijie Dai ◽  
Shining Li ◽  
Wenbin Ji ◽  
Zhenlin Sun ◽  
Yufeng Zhao

Purpose This study aims to realize the constant force grinding of automobile wheel hub. Design/methodology/approach A force control strategy of backstepping + proportion integration differentiation (PID) is proposed. The grinding end effector is installed on the flange of the robot. The robot controls the position and posture of the grinding end actuator and the grinding end actuator controls the grinding force output. First, the modeling and analysis of the grinding end effector are carried out, and then the backstepping + PID method is adopted to control the grinding end effector to track the expected grinding force. Finally, the feasibility of the proposed method is verified by simulation and experiment. Findings The simulation and experimental results show that the backstepping + PID strategy can track the expected force quickly, and improve the dynamic response performance of the system and the quality of grinding and polishing of automobile wheel hub. Research limitations/implications The mathematical model is based on the pneumatic system and ideal gas, and ignores the influence of friction in the working process of the cylinder, so the mathematical model proposed in this study has certain limitations. A new control strategy is proposed, which is not only used to control the grinding force of automobile wheels, but also promotes the development of industrial control. Social implications The automatic constant force grinding of automobile wheel hub is realized, and the manpower is liberated. Originality/value First, the modeling and analysis of the grinding end effector are carried out, and then the backstepping + PID method is adopted to control the grinding end effector to track the expected grinding force. The nonlinear model of the system is controlled by backstepping method, and in the process, the linear system composed of errors is obtained, and then the linear system is controlled by PID to realize the combination of backstepping and PID control.


Author(s):  
Bronius Baksys ◽  
Jolanta Baskutiene ◽  
Saulius Baskutis

Purpose This paper aims to consider the experimental and theoretical investigation of the vibratory alignment of the peg-hole, when the peg is fixed in the remote centre compliance (RCC) device, and the vibrations are provided either to the hole or to the peg. Design/methodology/approach The experimental analysis of the circular and rectangular peg-hole vibratory alignment using the attached to the robot arm RCC device, under vibratory excitation of the hole, has been performed. The parameters of the vibratory excitation and the part-to-part pressing force influence on the alignment process have been analysed. The mathematical approach of the vibratory alignment using the passive compliance device with the vibrations provided to the peg has been proposed, and the simulation has been carried out. Findings The research has approved the applicability of the RCC device for both of the vibratory alignments of the non-chamfered peg-hole parts either circular or rectangular ones. The compensation of the axial misalignments has been resulted by the directional displacement of the peg supported compliantly. To perform the successful alignment of the parts, it has been necessary to adjust the frequency and the amplitude of the vibrations, the pressing force, the lateral, as well as the angular stiffness of the device. Research limitations/implications The experiments on the vibratory alignment of the rectangular peg-hole parts have been carried out considering only the translational misalignment moved into one direction. The non-impact regime of the vibratory alignment has been analysed. Practical implications The obtained results can be applied in designing the reliable and efficient devices of the vibratory assembly for the alignment of the non-chamfered peg-hole parts, as well as for chamfered ones, if the axial misalignment exceeds the width of the chamfer. The vibratory technique and passive compliance provide possibility to accomplish the assembly operations using the non-expensive low accuracy robots. Originality/value The new method and the mathematical approach of the vibratory assembly using the RCC device can ensure the reliable alignment of the non-chamfered parts, chamfered circular and the rectangular ones, in case the axial misalignment exceeds the assembly clearance, and prevent jamming and wedging.


2014 ◽  
Vol 986-987 ◽  
pp. 810-813
Author(s):  
Ying Li Shao

The exhaust noise, which falls into low-frequency noise, is the dominant noise source of a diesel engines and tractors. The traditional exhaust silencers, which are normally constructed by combination of expansion chamber, and perforated pipe or perforated board, are with high exhaust resistance, but poor noise reduction especially for the low-frequency band noise. For this reason, a new theory of exhaust muffler of diesel engine based on counter-phase counteracts has been proposed. The mathematical model and the corresponding experimental validation for the new exhaust muffler based on this theory were performed.


Author(s):  
Debraj Sarkar ◽  
Debabrata Roy ◽  
Amalendu Bikash Choudhury ◽  
Sotoshi Yamada

Purpose A saturated iron core superconducting fault current limiter (SISFCL) has an important role to play in the present-day power system, providing effective protection against electrical faults and thus ensuring an uninterrupted supply of electricity to the consumers. Previous mathematical models developed to describe the SISFCL use a simple flux density-magnetic field intensity curve representing the ferromagnetic core. As the magnetic state of the core affects the efficient working of the device, this paper aims to present a novel approach in the mathematical modeling of the device with the inclusion of hysteresis. Design/methodology/approach The Jiles–Atherton’s hysteresis model is utilized to develop the mathematical model of the limiter. The model is numerically solved using MATLAB. To support the validity of model, finite element model (FEM) with similar specifications was simulated. Findings Response of the limiter based on the developed mathematical model is in close agreement with the FEM simulations. To illustrate the effect of the hysteresis, the responses are compared by using three different hysteresis characteristics. Harmonic analysis is performed and comparison is carried out utilizing fast Fourier transform and continuous wavelet transform. It is observed that the core with narrower hysteresis characteristic not only produces a better current suppression but also creates a higher voltage drop across the DC source. It also injects more harmonics in the system under fault condition. Originality/value Inclusion of hysteresis in the mathematical model presents a more realistic approach in the transient analysis of the device. The paper provides an essential insight into the effect of the core hysteresis characteristic on the device performance.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Bin Wang ◽  
Nanyue Xu ◽  
Pengyuan Wu ◽  
Rongfei Yang

Purpose The purpose of this paper is to provide a new hydrostatic actuator controlled by a piezoelectric piston pump and to reveal its characteristics. Design/methodology/approach In this paper, a piezoelectric pump with passive poppet valves and hydraulic displacement amplifier is designed as a new control component in a hydrostatic actuator for high actuation capacity. A component-level mathematical model is established to describe the system characteristics. Simulation verification for cases under typical conditions is implemented to evaluate the delivery behavior of the pump and the carrying ability of the actuator. Findings By using the displacement amplifier and the passive distributing valves, simulation demonstrates that the pump can deliver flow rate up to 3 L/min, and the actuator controlled by this pump can push an object weighing approximately 50 kg. In addition, it is particularly important to decide a proper amplification ratio of the amplifier in the pump for better actuation performance. Originality/value The piezoelectric pump presented in this paper has its potential to light hydrostatic actuator. The model constructed in this paper is valid for characteristic analysis and performance evaluation of this pump and actuators.


Author(s):  
Jiajia Chen ◽  
Yuhan Ma ◽  
Shiyou Yang

Purpose The purpose of this paper is to provide an accurate model and method to simulate the transient performances of an insulated gate bipolar transistor (IGBT) in an arbitrary free-carrier injection condition. Design/methodology/approach A numerical model and method for solving the physics-based model, an ambipolar diffusion equation-based model, of an IGBT is proposed. Findings The results of the proposed model are very close to the tested ones. Originality/value A mathematical model for an IGBT considering all free-carrier injection conditions is introduced, and a numerical solution methodology is proposed.


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