Combining Inverse Dynamics With Traditional Mechanism Synthesis to Improve the Performance of High Speed Machinery

2008 ◽  
Author(s):  
Robert Rayner ◽  
M. Necip Sahinkaya ◽  
Ben Hicks
Keyword(s):  
Mechanism Design ◽  
High Speed ◽  
Inverse Dynamics ◽  
Dynamic Performance ◽  
Performance Criteria ◽  
Alternative Mechanism ◽  
Analysis Tool ◽  
Mechanism Synthesis ◽  
Inverse Dynamic ◽  
Modeling And Analysis

This paper describes a unique, computer-based, mechanism design strategy that takes into account both kinematic and dynamic performance criteria at the synthesis stage of the design process. The strategy can be used to investigate improvements in the design of any existing mechanism with geometric redundancy in its output path. By iteratively varying the form of this redundant portion of the output path, alternative potentially better mechanism designs can be generated using a traditional mechanism synthesis and kinematic analysis method. The generated designs with the most desirable kinematic characteristics can be selected and analyzed using a multi-body, dynamic modeling and analysis tool. Using forward and inverse dynamic analysis the quality of the designs can be quantified. This paper describes work done to apply the strategy to an existing mechanism. An alternative mechanism design was identified with superior dynamic qualities. Kinematic performance was not sacrificed.

Inverse Dynamic Analysis and Linearisation of a High Speed Parallel Mechanism

2005 ◽  
Author(s):  
M. Necip Sahinkaya ◽  
Yanzhi Li
Keyword(s):  
Dynamic Analysis ◽  
Parallel Mechanism ◽  
High Speed ◽  
Inverse Dynamics ◽  
Motion Path ◽  
Model Parameters ◽  
Control Input ◽  
Inverse Dynamic ◽  
Inverse Dynamic Analysis ◽  
Dynamics Models

Inverse dynamic analysis of a three degree of freedom parallel mechanism driven by three electrical motors is carried out to study the effect of motion speed on the system dynamics and control input requirements. Availability of inverse dynamics models offer many advantages, but controllers based on real-time inverse dynamic simulations are not practical for many applications due to computational limitations. An off-line linearisation of system and error dynamics based on the inverse dynamic analysis is developed. It is shown that accurate linear models can be obtained even at high motion speeds eliminating the need to use computationally intensive inverse dynamics models. A point-to-point motion path for the mechanism platform is formulated by using a third order exponential function. It is shown that the linearised model parameters vary significantly at high motion speeds, hence it is necessary to use adaptive controllers for high performance.

Dynamics modeling and analysis of a four-wheel independent motor-drive virtual-track train

2020 ◽  
pp. 146441932096401
Author(s):  
Zhonghui Yin ◽  
Jiye Zhang ◽  
Haiying Lu ◽  
Weihua Zhang
Keyword(s):  
High Speed ◽  
Load Capacity ◽  
Dynamic Performance ◽  
Spatial Dynamics ◽  
Dynamic Responses ◽  
Dynamics Modeling ◽  
Dynamics Model ◽  
Coupling Effects ◽  
Dynamic Interactions ◽  
Modeling And Analysis

Due to urbanisation and the economic challenges of traffic, it is urgently necessary to develop an environmentally friendly virtual-track train with suitable speed, high load capacity and low construction cost in China. To guide the design and evaluate this train’s dynamic behaviour, a spatial-dynamics model has been developed based on the dynamics theory and tyre-road interaction. The proposed dynamics model comprises mechanical vehicle systems, traction and braking characteristics and tyre-road dynamic interactions. The coupling effects amongst those systems of virtual track train are derived theoretically for the first time. The nonlinear characteristics of the tyre are modelled by the transit tyre-magic formula with consideration of road irregularities. Based on a designed PID controller and the comprehensive dynamics model, the dynamic performance of the system can be revealed considering motion coupling effects and complicated excitations, especially under traction and braking conditions. The dynamic responses of whole virtual track train can be obtained by numerical integration under different conditions. The vibration characteristics of such train are assessed under running at a constant speed and during the traction/braking process. The results show that the vibrations of the vehicle system are significantly influenced by road irregularities, especially at high speed ranges. The motions and vibrations of different components are intensive coupled, which should not to be neglected in the dynamics assessment of the virtual track train. Besides, the dynamics model can also be applied to dynamics-related assessment (fatigue, strength and some damage conditions, et al.) and parameter optimisation of the virtual-track train.

Synthesis of Demand Signals for High Speed Operation of a Packaging Mechanism

2007 ◽  
Author(s):  
M. Necip Sahinkaya ◽  
Robert M. C. Rayner ◽  
Geoff Vernon ◽  
Graham Shirley ◽  
Raj K. Aggarwal
Keyword(s):  
Computer Model ◽  
High Speed ◽  
Inverse Dynamics ◽  
Dynamic Performance ◽  
Experimental Tests ◽  
Performance Improvements ◽  
Analytical Work ◽  
Significant Performance ◽  
Vibration Problems ◽  
Driving Torque

The aim of the work described in this paper is to improve the dynamic performance of a one-degree-of-freedom packaging mechanism through demand signal shaping to minimize the peak to peak motor torque. This enables the mechanism to operate at higher speeds with lower vibration and noise levels, and hence with higher accuracy. Initial experimental tests have shown the motion of the Woodpecker mechanism to suffer from dynamic, vibration problems synonymous with a mechanism possessing large amounts of harmonic content in its output motion. The dynamics of the Woodpecker mechanism and the accompanying servo system are developed and the likely causes of the dynamic issues experienced are identified. A computer model of the complete system drive unit is developed utilizing experimental data. The intention is to use the model in further detailed analytical work to shape the velocity demand signal passed to the system. Inverse dynamics are used to derive the variation in driving torque, which must be exerted on the mechanism crank by the drive motor for the mechanism to achieve a constant speed over the complete cycle. Based on the computer model, a novel technique to shape the speed demand signal is developed and it is shown that significant performance improvements can be achieved without re-synthesizing the mechanism or altering the existing industrial controller.

Dynamic Analysis of a Parallel Pick-and-Place Robot With Flexible Links

2008 ◽  
Author(s):  
Haihong Li ◽  
Zhiyong Yang
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Lithium Ion ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Modeling And Analysis ◽  
Flexible Links ◽  
Pick And Place ◽  
Floating Frame ◽  
Pick And Place Operation

The dynamic modeling and analysis of a 2-DOF translational parallel robot for high-speed pick-and-place operation was presented. Considering the flexibility of all links, the governing equation of motion of a flexible link is formulated in the floating frame of reference using Euler-Lagrange method. A kineto-elasto dynamic model of the system is achieved, ready for modal analysis. Simulation in FEM software showed the similar modes with above computational result in typical location and rotation. The dynamic experiment presented the dominant modes and proved the theoretical analysis and simulation. The Diamond robot used in Lithium-ion battery sorting was taken as an example to demonstrate how to finish above studies. The result shows that the mechanism has good dynamic performance. The work is available for all parallel robots with flexible links.

scholarly journals AN INVERSE DYNAMICS METHOD FOR RAILWAY VEHICLE SYSTEMS

Transport ◽  
2013 ◽  
Vol 29 (1) ◽  
pp. 107-114 ◽  
Author(s):  
Tao Zhu ◽  
Shoune Xiao ◽  
Guangwu Yang ◽  
Weihua Ma ◽  
Zhixin Zhang
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Inverse Dynamics ◽  
Time History ◽  
Inverse Model ◽  
Contact Forces ◽  
Railway Vehicle ◽  
Inverse Dynamic ◽  
Multibody Model ◽  
History Of

The wheel–rail action will obviously be increased during the vehicles in high-speed operation state. However, in many practical cases, direct measurement of the wheel–rail contact forces cannot be performed with traditional procedures and transducers. An inverse mathematical dynamic model for the estimation of wheel–rail contact forces from measured accelerations was developed. The inverse model is a non-iteration recurrence method to identify the time history of input excitation based on the dynamic programming equation. Furthermore, the method overcomes the weakness of large fluctuations which exist in current inverse techniques. Based on the inverse dynamic model, a high-speed vehicle multibody model with twenty-seven Degree of Freedoms (DOFs) is established. With the measured responses as input, the inverse vehicle model can not only identify the responses in other parts of vehicle, but also identify the vertical and lateral wheel–rail forces respectively. Results from the inverse model were compared with experiment data. In a more complex operating condition, the inverse model was also compared with results from simulations calculated by SIMPACK.

Symmetric Dichotomy Based Inverse Dynamics of a High-Speed Flexible Beam

1999 ◽  
Author(s):  
Guoli Wang ◽  
Youfu Li ◽  
Weiliang Xu
Keyword(s):  
Time Domain ◽  
High Speed ◽  
Inverse Dynamics ◽  
Input State ◽  
Flexible Beam ◽  
Inverse Dynamic ◽  
Computational Burden ◽  
Efficient Scheme ◽  
The Time Domain ◽  
Bounded Input

Abstract The symmetric acausal/causal dichotomy based model is developed for the internal dynamics of a high-speed flexible beam, and the resultant modeling redundancy is revealed. The efficient scheme of computing the bounded input-state trajectories is proposed to relieve the redundant computational burden of the time-domain inverse dynamic solutions, and its implication to trajectory planning is also investigated.

A COMPARATIVE STUDY OF CAM MOTIONS FOR HIGH-SPEED SEMI-RIGID FOLLOWER CAM SYSTEMS

1988 ◽  
Vol 12 (3) ◽  
pp. 121-128 ◽  
Author(s):  
P.S. GREWAL ◽  
W.R. NEWCOMBE
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Poor Performance ◽  
Performance Criteria ◽  
Vibrational Response ◽  
High Speeds ◽  
Speed Performance ◽  
Cam Profile ◽  
Torque Values ◽  
Profile Errors

A study is presented on the comparison of all the popular cam motions based on a refined dynamic model which takes into account the effects of cam profile errors and most of the important factors that influence the dynamic performance for a semi-rigid follower cam system. A stochastic model is developed to simulate the input signal resulting from the cam motion, including the deviations due to profile errors. The performance criteria comprise the vibrational response at the follower and the dynamic characteristics at the cam. It has been established that, at high speeds, it is not the vibrational behaviour, but the follower tendency to jump and the maximum contact force and cam torque values which determine the dynamic performance. The Modified-Sine, Simple Harmonic and 3-4-5 Polynomial motions have been shown to exhibit superior high speed performance compared to that of the popular Cycloidal and Modified Trapezoidal motions. Higher-order Polynomial motions give very poor performance at high speeds.

scholarly journals Mathematical Modeling on Statics and Dynamics of Aerostatic Thrust Bearing with External Combined Throttling and Elastic Orifice Fluid Flow Regulation

Lubricants ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 57 ◽  
Author(s):  
Vladimir Kodnyanko ◽  
Stanislav Shatokhin ◽  
Andrey Kurzakov ◽  
Yuri Pikalov
Keyword(s):  
Mathematical Modeling ◽  
High Speed ◽  
Metal Cutting ◽  
Load Capacity ◽  
Dynamic Performance ◽  
Performance Criteria ◽  
Design Parameters ◽  
Machining Accuracy ◽  
Aerostatic Bearing ◽  
Aerostatic Bearings

As aerostatic bearings are used in high-speed metal-cutting machines to increase machining accuracy, there is the need to improve their characteristics, including compliance, which is usually high. In practical applications, a significant reduction of bearing compliance is often necessary, sometimes down to zero and even negative values, to ensure automatic compensation of the elastic deformation in the machine technological system. A decrease in compliance leads to deterioration in the dynamic performance of the bearing, so it is necessary to develop new designs that meet the above requirements. This article considers an aerostatic bearing, in which decrease in compliance is ensured by the use of air throttling with elastic orifices. To ensure its stability, the principle of combined external throttling was applied, which can substantially improve the dynamics of conventional aerostatic bearings. A mathematical model of the elastic orifice deformation was developed, together with the flow rate performance calculation method. The method ensured full qualitative and satisfactory quantitative agreement with the experimental data. The model was used in the mathematical modeling of the aerostatic bearing movement. The article also proposes a method to calculate the static load capacity and compliance of a bearing, as well as a numerical method for fast computation of its dynamic performance, which allows for real-time multi-parameter optimization by the bearing dynamic performance criteria. The study showed that there is an optimal set of design parameters for which low, zero, and negative static compliance of the bearing is ensured, with the necessary stability margin, high speed, and the non-oscillatory nature of the transient processes.

Inverse Dynamics Analysis of a 2-DOF Planar Parallel Manipulator

2010 ◽  
Vol 44-47 ◽  
pp. 1848-1852
Author(s):  
Xiao Rong Zhu ◽  
Hui Ping Shen ◽  
Wei Zhu ◽  
Lan Cai
Keyword(s):  
Parallel Manipulator ◽  
Inverse Dynamics ◽  
Driving Forces ◽  
Dynamic Performance ◽  
Operating Mode ◽  
Moment Of Inertia ◽  
Inverse Dynamic ◽  
Operating Modes ◽  
Inverse Solutions ◽  
Dynamic Performance Analysis

The dynamic characteristics of the parallel mechanism depend strongly on the operating modes corresponding to different inverse solutions, but few of them have been involved with. In this paper, a new kind of 2-DOF parallel manipulator actuated horizontally by two parallel linear actuators is investigated. Firstly, the four inverse solutions of this manipulator are derived and analyzed; Secondly, the closed form inverse dynamic model is presented using the Lagrange approach based on the generalized system coordinates. An explicit formula of the equivalent moment of inertia, driving forces and consumed energy of the mechanism are investigated; Finally, the changes of equivalent moment of inertia, actuator force and energy consumption of the mechanism in different operating mode are analyzed through the dynamic numerical simulation. The results show that, for a given motion, the configuration and the operating modes have a significant influence on the equivalent moment of inertia and actuator force. The analysis provides necessary information for dynamic performance analysis and control of this parallel manipulator.

Performance Criteria for High-Speed Crank-and-Rocker Linkages—Part II: Spherical Crank-and-Rocker Linkages

1979 ◽  
Vol 101 (1) ◽  
pp. 26-31 ◽  
Author(s):  
H. Funabashi ◽  
F. Freudenstein
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Performance Criteria ◽  
Link Length ◽  
Angle Variation ◽  
Numerical Examples ◽  
Transmission Angle ◽  
The Dead ◽  
Sine Functions

In Part I proportions were derived for high-speed plane crank-and-rocker mechanisms. In this part, the corresponding developments are given for spherical crank-and-rocker mechanisms. The ratios of the sine functions of the transmission angles and of the rocker accelerations—both at the dead-center positions—remain the static and dynamic performance criteria of the linkage. The results are illustrated by numerical examples, which show the influence of these ratios on the transmission-angle variation, rocker acceleration and the ratio of minimum to maximum link length.

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