Development of the Tri-Level Variable Rate Trajectory With Discretely Vanishing Shock for Optimum Design

1988 ◽  
Vol 110 (1) ◽  
pp. 88-92 ◽  
Author(s):  
Steven N. Kramer ◽  
Richard L. Curran
Keyword(s):  
Operating Cost ◽  
Robotic Manipulators ◽  
Dynamic Responses ◽  
Variable Rate ◽  
Time Intervals ◽  
The One ◽  
Mechanical Devices ◽  
Level Variable ◽  
General Motion ◽  
General Method

The tri-level variable rate trajectory is a general motion which can be applied to programmable controllers, robotic manipulators, mechanisms, and mechanical devices where the input crank orientation, velocity, and acceleration vary with time. In the work presented here, the tri-level variable rate trajectory is an extension of the variable-rate trans-symmetric motion developed by the first author in 1984. That motion and the one developed here consist of discrete segments of constant and linearly varying accelerations occurring over specified time intervals, thereby providing versatile programmable trajectories with several advantages over the constant acceleration motion, simple harmonic motion, cycloidal motion, and the popular polynomial trajectories used in robotics. The tri-level variable-rate trajectory allows much more control of the acceleration contour of the motion and as a result, there is a decrease in the power required, a decrease in the operating cost, and a decrease in dynamic responses such as shock, vibration, and shaking force and virtual elimination of the overshoot problem that sometimes accompanies the polynomial segment motions. This is a general method which can be applied to many applications. The results of applying this trajectory to a complex machine controller are presented as an example.

Development of the Variable-Rate Transymmetric Motion With Discretely Vanishing Shock

1984 ◽  
Vol 106 (1) ◽  
pp. 109-113 ◽  
Author(s):  
S. N. Kramer
Keyword(s):  
Constant Velocity ◽  
Angular Displacement ◽  
Operating Cost ◽  
Dynamic Responses ◽  
Variable Rate ◽  
Constant Acceleration ◽  
Functional Relationships ◽  
Rest Position ◽  
New Type ◽  
Velocity Motion

In industry when a link, crank, or other mechanical component is to be rotated from one rest position to another, it is necessary to establish appropriate functional relationships for angular displacement, velocity, and acceleration versus time such that the output motion satisfies certain kinematic and dynamic requirements. In the work presented here, a new type of motion is developed which has distinct advantages over constant velocity motion, constant acceleration motion, simple harmonic motion, cycloidal motion, and polynomial motions. The “variable-rate transymmetric” motion allows a designer to assign specific portions of the motion to be described by a linearly varying acceleration and other portions by a constant acceleration. As a result, the designer can decrease the power required, decrease the operating cost, and decrease dynamic responses such as shock, vibration, and shaking force.

A stochastic process whose successive intervals between events form a first order Markov chain — I

1968 ◽  
Vol 5 (03) ◽  
pp. 648-668
Author(s):  
D. G. Lampard
Keyword(s):  
Markov Chain ◽  
Point Processes ◽  
Electronic Device ◽  
Statistical Properties ◽  
Time Intervals ◽  
First Order ◽  
Stochastic Point Process ◽  
Order Markov Chain ◽  
The One ◽  
Stochastic Point Processes

In this paper we discuss a counter system whose output is a stochastic point process such that the time intervals between pairs of successive events form a first order Markov chain. Such processes may be regarded as next, in order of complexity, in a hierarchy of stochastic point processes, to “renewal” processes, which latter have been studied extensively. The main virtue of the particular system which is studied here is that virtually all its important statistical properties can be obtained in closed form and that it is physically realizable as an electronic device. As such it forms the basis for a laboratory generator whose output may be used for experimental work involving processes of this kind. Such statistical properties as the one and two-dimensional probability densities for the time intervals are considered in both the stationary and nonstationary state and also discussed are corresponding properties of the successive numbers arising in the stores of the counter system. In particular it is shown that the degree of coupling between successive time intervals may be adjusted in practice without altering the one dimensional probability density for the interval lengths. It is pointed out that operation of the counter system may also be regarded as a problem in queueing theory involving one server alternately serving two queues. A generalization of the counter system, whose inputs are normally a pair of statistically independent Poisson processes, to the case where one of the inputs is a renewal process is considered and leads to some interesting functional equations.

scholarly journals Retinomotor movements in the Antarctic fish Trematomus newnesi Boulenger submitted to different environmental light conditions

2007 ◽  
Vol 24 (2) ◽  
pp. 457-462 ◽  
Author(s):  
Lucélia Donatti ◽  
Edith Fanta
Keyword(s):  
Pigment Epithelium ◽  
Antarctic Fish ◽  
Constant Darkness ◽  
Time Intervals ◽  
Mean Values ◽  
Environmental Light ◽  
The Mean ◽  
The Difference ◽  
The One ◽  
The Antarctic

The Antarctic fish Trematomus newnesi (Boulenger, 1902) occurs from benthic to pelagic habitats, in seasonally and daily varied photic conditions that induce retinomotor movements. Fish were experimentally kept under constant darkness or light, and 12Light/12Dark for seven days. The retinomotor movement of the pigment epithelium was established through the pigment index, while that of the cones was calculated as the length of the myoid. The retinomotor movement of the pigment epithelium in T.newnesi,revealed that the adaptation to constant light occurred in the one hour of exposure, remaining constant for the next seven days. However, the adaptation to constant darkness, was slower. The difference between the mean values of the pigment indices in the time intervals of sampling was significant in the first hours of the experiment, and only after six hours they were not significant any more. The myoid of cones became elongated in darkness and contracted in light. In the experiments where T.newnesiwas exposed initially to 12 hours light followed by 12 hours darkness 12 was evidenced that the speed and intensity of the retinomotor movements was higher when darkness changed into light, than when light changed into darkness.

The sensitivity of economic gains from high-speed planting

2017 ◽  
Vol 8 (2) ◽  
pp. 662-667
Author(s):  
C. R. Dillon ◽  
J. Shockley ◽  
T. Mark
Keyword(s):  
Optimization Model ◽  
Technological Progress ◽  
High Speed ◽  
Operating Cost ◽  
Cost Savings ◽  
Variable Rate ◽  
Net Returns ◽  
Variable Rate Application ◽  
Technology Changes ◽  
Profit Potential

Recent technological progress in high-speed planting (HSP) warrants economic analysis of its potential. A whole farm optimization model of a 1000 ha Kentucky, USA corn and soybean operation finds that operating cost savings (labor, fuel, tractor repairs) and yield increases couple in recovering annual ownership costs of HSP technology. Changes in farm net returns are positive for all 12-row planter scenarios and all double speed cases for the 16-row planter but not for a 50% increase in speed with the 16-row planter. The greatest profit potential occurred when adopting the combination of HSP and variable rate application (VRA), with increased net returns of up to 6.57% compared to conventional speed no VRA for the 12-row planter.

scholarly journals The Synthesis of Stochastic Circuits for Nanoscale Computation

2009 ◽  
Vol 1 (4) ◽  
pp. 39-57 ◽  
Author(s):  
Weikang Qian ◽  
John Backes ◽  
Marc D. Riedel
Keyword(s):  
Data Structures ◽  
Self Assembly ◽  
Logic Synthesis ◽  
Nanowire Arrays ◽  
Stochastic Nature ◽  
Symbolic Data ◽  
The One ◽  
High Degree ◽  
Stochastic Circuits ◽  
General Method

Emerging technologies for nanoscale computation such as self-assembled nanowire arrays present specific challenges for logic synthesis. On the one hand, they provide an unprecedented density of bits with a high degree of parallelism. On the other hand, they are characterized by high defect rates. Also they often exhibit inherent randomness in the interconnects due to the stochastic nature of self-assembly. We describe a general method for synthesizing logic that exploits both the parallelism and the random effects. Our approach is based on stochastic computation with parallel bit streams. Circuits are synthesized through functional decomposition with symbolic data structures called multiplicative binary moment diagrams. Synthesis produces designs with randomized parallel components—and operations and multiplexing—that are readily implemented in nanowire crossbar arrays. Synthesis results for benchmarks circuits show that our technique maps circuit designs onto nanowire arrays effectively.

The Changing Retail Cost Model

2020 ◽  
pp. 145-157
Author(s):  
Alan Treadgold ◽  
Jonathan Reynolds
Keyword(s):  
Business Models ◽  
Cost Model ◽  
Operating Cost ◽  
Sustainable Performance ◽  
Additional Costs ◽  
New Entrants ◽  
To Come ◽  
Established Firms ◽  
The One ◽  
The Cost

This chapter examines the changing retail cost model. As established firms re-think existing business models, most will need to come to terms with a rather different operating cost model than the one they have been used to in a pre-internet era, when retailing was conducted entirely out of physical stores. Equally, new entrants may struggle to achieve sustainable performance without understanding the full implications of their evolving cost base. In an omni-channel world where shoppers are, as we have discussed, showing much more appetite to shop online and across multiple touchpoints, the implications for the cost model of traditional retailers are considerable. The extent to which any additional costs of omni-channel retailing become ‘baked in’ to the model is also up for discussion.

A new algorithm for numerical modelling of impurity transport in the frame of statistically homogeneous sharply contrasting media

2019 ◽  
Vol 34 (6) ◽  
pp. 339-351 ◽  
Author(s):  
Petr S. Kondratenko ◽  
Leonid V. Matveev ◽  
Alexander D. Vasiliev
Keyword(s):  
Numerical Modelling ◽  
Contaminant Transport ◽  
Integral Kernel ◽  
Time Intervals ◽  
One Dimensional ◽  
Time Representation ◽  
Impurity Transport ◽  
The One ◽  
Analytical Expressions ◽  
Good Agreement

Abstract A new method is developed to calculate characteristics of contaminant transport (including non-classical regimes) in statistically homogeneous sharply contrasting media. A transport integro-differential equation in the space-time representation is formulated on the basis of the model earlier proposed by one of the authors (L. M.). Analytical expressions for transport characteristics in limiting time intervals in the one-dimensional case are derived. An interpolation form is proposed for the integral kernel of the transport equation. On a basis of this expression, an algorithm is developed for numerical modelling the contaminant transport in statistically homogeneous sharply contrasting media. Trial numerical 1D calculations are performed based on this algorithm. Good agreement was found between the numerical simulation results and the asymptotic analytical expressions.

First Paper: A General Approach to Hydraulic Lock

1967 ◽  
Vol 182 (1) ◽  
pp. 595-602 ◽  
Author(s):  
P. Dransfield ◽  
D. M. Bruce ◽  
M. Wadsworth
Keyword(s):  
Reynolds Equation ◽  
Lateral Force ◽  
Hydraulic Control ◽  
Dimensional Solution ◽  
One Dimensional ◽  
Particular Solutions ◽  
Piston Cylinder ◽  
The One ◽  
Hydraulic Control System ◽  
General Method

The present state of knowledge on the hydraulic lock phenomena of oil hydraulic control system components is reviewed briefly. A general one-dimensional solution of the Reynolds equation which governs hydraulic lock is presented. The solution embraces the particular solutions of past workers, and allows ready solution for piston-cylinder configurations for which a one-dimensional solution is adequate. A general method for making full solutions of the Reynolds equation is presented, requiring the use of a digital computer for particular solutions. Pressure distribution, the lateral force on the piston which produces hydraulic lock, and the location of the lateral force can be obtained. The commonly occurring case of a single-land piston lying tilted in its bore is examined in detail. The limit of accuracy of a one-dimensional solution is clearly shown by illustrating the discrepancies between the one-dimensional and two-dimensional solutions for several configurations.

The finite dam II

1970 ◽  
Vol 7 (3) ◽  
pp. 599-616 ◽  
Author(s):  
P. B. M. Roes
Keyword(s):  
Time Intervals ◽  
Transient Behaviour ◽  
Continuous Release ◽  
Poisson Input ◽  
Excess Water ◽  
Starting Point ◽  
The Laplace Transform ◽  
Uniqueness Of The Solution ◽  
The One ◽  
Finite Dam

SummaryA weir of capacity K is considered in which the water inflow is a process with stationary independent increments. Unless the weir is empty, there is a continuous release of water at unit rate; if K is finite the weir may become full in which case the excess water overflows instantaneously. A weir for which K is infinite will be referred to as infinite dam. For the latter the transient behaviour is well known if the input possesses a second moment (cf. e.g., Prabhu [7]) and serves as the starting point for the present paper. This result is first extended to yield the Laplace transform (L.T.) of the trivariate Laplace-Stieltjes transform (L.S.T.) of the content v(t) at time t, the input X(t) in (0, t) and the total time d(t) in the interval (0, t) during which the dam is dry. (Incidentally, the last two quantities, for relevant time intervals, will be carried throughout.) Then we use a relation between the latter and the L.S.T. of the expected number of downward level y crossings of the v(t) process established in Roes [9]. Since the dam processes considered are Markov processes, we have therewith the L.S.T. of the renewal function of the renewal process imbedded at level y. From this, one finds the L.S.T.'s of first entrance and taboo first entrance times (for their definition see introduction). Next we calculate the first skip times for the infinite dam from the first entrance times and the L.T. of the L.S.T. of v(t). It is then a routine matter to determine the taboo first skip times. From the (taboo) first entrance and skip times we derive the first entrance times for the finite dam, which in turn lead to the renewal functions of the renewal processes imbedded in the finite dam content process v*(t) and hence to the transient behaviour of the finite dam.The advantage of the present approach over the one given in Roes [8] is that it is entirely probabilistic and avoids involved analytic arguments. As a result, the question of uniqueness of the solution does not arise, while more insight is obtained in the structure. The L.S.T. of several first entrance times and first skip times have been derived by Cohen [2] for compound Poisson input.

Influences of Subgrade Structure Form on Dynamic Responses of Railway Subgrade under Cyclic Loading

2016 ◽  
Vol 851 ◽  
pp. 757-762
Author(s):  
Jun Hua Xiao
Keyword(s):  
Plastic Deformation ◽  
Cyclic Loading ◽  
Maximum Stress ◽  
Dynamic Stress ◽  
Dynamic Stiffness ◽  
Field Tests ◽  
Dynamic Responses ◽  
Structure Form ◽  
The One ◽  
Moving Train

This paper presents conducted field tests of cyclic loading for railway subgrade. These tests studied the influences of subgrade structure forms of embankment and cutting on the dynamic responses of railway subgrade. The considered dynamic responses included the distribution of dynamic stress in railway subgrade, and the elastic deformation, dynamic stiffness, and cumulative plastic deformation on subgrade surface. The number of cyclic loading in testing was separately about two millions for an embankment and a cutting. The dynamic deviator stress applied on subgrade surface was 92kPa to simulate the maximum stress induced by moving train for the designed railway. Gathered data showed that the dynamic stiffness on subgrade surface for a cutting was approximately a half of the one for an embankment. However, the cumulative plastic deformation was essentially the same for the two forms of subgrade (i.e. the embankment and the cutting). These results provide references for the design of railway subgrade.

Sign in / Sign up

Export Citation Format

Share Document