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Development of a software for simulating active force control schemes of a two-link planar manipulator

Development of a software for simulating active force control schemes of a two-link planar manipulator

Abstract. The paper describes the development of a software in the form of an interactive computer program that integrates a number of robotic control schemes with the active force control (AFC) strategy as the key element of the robotic system that assumes a rigid two-link planar configuration. The various AFC schemes are employed in conjunction with a number of conventional and intelligent techniques embedded in the main control loop to approximate the estimated inertia matrix of the robot arm. The schemes have been individually developed and rigorously experimented through simulation studies. The results of these studies clearly indicate that the AFC technique provides a practical solution to enhance the robustness of the robotic system even in the wake of uncertainties, disturbances and varied loading conditions. Thus, it is deemed useful to develop software that can integrate a number of individual AFC schemes into a single program using a graphic user interface (GUI) technique. In this manner, the user can effectively select and execute any scheme by the manipulation of a few keystrokes or buttons of the input devices. This resulted in a program that is user friendly, readily accessible, flexible and proved very convenient. On top of that, the graphical results can be observed and analysed on-line while the program is running. By using MATLAB and its GUI facility, all the AFC schemes already described in the previous works such as the AFC with crude approximation method, AFC and Iterative Learning (AFCAIL), AFC and Neural Network (AFCANN), AFC and Fuzzy Logic (AFCAFL), and AFC and Genetic Algorithm (AFCAGA) schemes were linked into a single menu-driven program where each of the scheme can be easily selected and executed by the user. A classic proportional-derivative (PD) control scheme was also included in the program for the purpose of benchmarking.

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Two-link musculoskeletal structure workspace force control

Two-link musculoskeletal structure workspace force control

Furthermore, to make a force control method work, there are several important variables that need to be considered. One of the important variables is the force axis that applies to the robot end-effector. This can be either or a combination of X-axis, Y-axis and Z-axis if the robot is modelled in 3 Dimensions. Other important variable for the robot to function well is the rotational angle or displacement of the joint compared to the previous joint. For example, if the robot is two-link robot and have two degree of freedom, there e are two angles that need to be considered which is the rotational angles or displacement between base of the robot and first joint of the robot, and rotational angles or displacement between first and second joint of the robot. Figure 1.0 show the three link robot with it variables.

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Multiple chronic health conditions and their link with labour force participation and economic status

Multiple chronic health conditions and their link with labour force participation and economic status

Within Australia, individuals who leave the labour force due to ill health may have access to a Disability Support Pension if they have medical confirmation that they cannot work due to a health condition and meet the eligibility criteria. The Employment and Support Allowance in the United Kingdom and the Supplemental Security Income scheme in the USA offer similar arrangements [52–54]. Despite this (limited) financial support from government, the financial burden of illness on individuals and their families will still be significant. It is documented that those who are dependent upon welfare as a primary source of income often have poor living standards and quality of life both within Australia [55,56].

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Zero 
		point energy conversion for self sustained generation

Zero point energy conversion for self sustained generation

The magneto-gravitic link (MGL) operational principle is in alternate usage in closed cycle of gravitation force and magnetic forces of repelling attraction of PM and repeated alternation of gravitation force which acts on the rotor magnets when shielding the PM [1] magnetic field by blinds-screens of permanent magnets magnetic fields where forces of PM magnetic repelling act on magnetic motor (MM) rotor when such magnetic shield between PM is absent. Rotor plate is the rotating part of the MGL. Rotor plate is made of hylam sheet of 4mm thickness. The sheet is laminated on the rotor surface. This hylam sheet is a plywood based, having good tensile strength. The rotor plate is circular in shape with a center hole of 25mm for the shaft to pass through. The diameter of the plate is 400mm.The plate sits on the shaft horizontally as shown in Figure-3. The rotor plate carries poles on it. The poles are permanent ceramic magnets. Each magnet is 80mm in diameter with a hole in center

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The Impact of Upper Link Length on the Output Parameters of a Tractor Set

The Impact of Upper Link Length on the Output Parameters of a Tractor Set

The measured results show a  positive impact of the  force in the  upper link of the  three‑point hitch, which was more significant in case of the  tractor set with the  plough equipped with an additional device for increasing of traction. In the case of the agrotechnical operation ‑ ploughing, the performance and energy parameters are stated in m3 of processed soil in order to assure higher objectivity. Comparable results can be found in the case of measurements that dealt with a similar issue but under different conditions or with different machines. In such cases, the fuel consumption saving with correctly adjusted machines or with the use of traction cylinders reaches several litres and there is also a significant positive effect in terms of slippage and performance of work sets.

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Influence of top link length of three point hitch on performance parameters of ploughing set

Influence of top link length of three point hitch on performance parameters of ploughing set

The disadvantage of increasing force may be re- duction of sensitivity of the regulation mechanism in the case that the force impulse is transferred through top link. Similar measurements were carried out by Ahokas (1996), who reported that when depth wheel was used, wheel slip ranged from 7–9%. In the case without the use of depth wheel the wheel slip achieved a value between 10% and 11%; this applies to rear axle drive. Moreover, he also drew attention to the larger variability of depth of ploughing, which increased by 13% without depth wheel. In the case of our measurements the coefficient of variation of depth was up to 10%, which was in the tolerance de- scribed by many authors (Skalweit 1952; Dwyer 1984), however, e.g. Dwyer et al. (1974) expanded the discussion of tolerance of 10%, as there is no ag-

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Modelling and predicting labor force productivity

Modelling and predicting labor force productivity

In developed countries, population estimates for the specific age are not available or too poor for quantitative analysis. However, for the modelling of the changes in productivity one can use estimates of real GDP per capita instead of the population estimates. This paper extends the set of studied countries and presents the link between P and G in Turkey, Spain, Belgium, Austria, Switzerland, and New Zealand. Moreover, the lag of productivity behind the change in real GDP allows predicting the former at various time horizons.

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SYNTHESIS OF FLEXIBLE 4-BAR LINKAGE CONSIDERING DEFORMATION

SYNTHESIS OF FLEXIBLE 4-BAR LINKAGE CONSIDERING DEFORMATION

Many works were done considering joint clearances in a mechanism. Due to joint clearance how deviation of coupler path occurs was studied. But in actual mechanism the real deviation generated will be more due to the deformation of the pin in the mechanism. In this paper attempt is made to minimize the deviation due to deformation. A number of works reported in the journals on dynamic behavior of flexible linkages and joint forces. Schwab et al. [1] analyzed the dynamic response of mechanisms and machines with revolute joint clearance .mechanical system was modeled by rigid or elastic bodies, and a comparison was made between several continuous contact force model. Feng et al. [2] analyzed the joint forces of planar linkage with joint clearance and presented a new optimization method which was based on optimizing mass distribution of links to decrease the change of joint forces. Tsai and Lai [3] presented an effective method to analyze the transmission performance of linkages with joint clearances. Equivalent kinematic pairs were used for modeling the motion freedoms originated from the joint clearances. Erkaya et al. [4] presented an investigation of influence of joint clearance on the path generation mechanism and its transmission angle. Joint clearance was treated as a mass- less virtual link and mathematical expression of its motion was obtained by using Lagrange’s equation. T.K.Naskar and S.Acharya [5] where a comprehensive experimental analysis is conducted for measuring dynamic response of jerk optimized, stress optimized and size optimized cams. It was seen that there were deviations of predicted cam displacements from actual displacements due to deformation of cam surface under contact stress. Flores, P.et.al [6] presented a methodology for the dynamic analysis of mechanical systems considering realistic joint characteristics, namely, joints with clearance and lubrication.

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Behavior of Modified Long Links with Supplemental Double Stiffeners on Eccentrically Braced Frames

Behavior of Modified Long Links with Supplemental Double Stiffeners on Eccentrically Braced Frames

Based on the results from the previous studies, failure of long links occurs at the end of the link. Some research has been done to avoid failure due to bending dominant force by adding stiffeners to the web and flange. Yurisman [14] conducted a study on short links that were added diagonal stiffeners on the web. Danesh [20] reported utilizing diagonal stiffeners on the web and supplemental stiffeners on the flange. Furthermore, Okazaki [13] and Hong [21] reported using supplemental double stiffeners in connecting a beam to the column and found excellent performances on the link. Stephens and Dusicka [22] reported that the use of continuous stiffeners on the short link could improve its performance, exceeding the standard shear link performance according to the requirements of AISC 341-10. Furthermore, Yurisman [14] and Danesh [16] reported that retrofitting the link delayed failure at the end of the link. Reinforcement at the ends of long links prevents the early failure that is preceded by the formation of the plastic hinge on the flange.

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Online Full Text

Online Full Text

The reaction force and reaction torque on the distal phalange at the joint of the pin (connecting link 3 and distal phalange) and the distal phalange can be measured. The reaction force and reaction torque on link 3 at the joint of the pin (connecting link 3 and distal phalange) and the link 3can be measured. This designed gripper is useful for grasping lightweight object with dexterous manipulation. By using interfacing circuits, programmable controls biomimetic approach can be inculcated to the grasping system. Dynamic simulation guides for analysis of various operational parameters such as real time controlling, better sequential moves…etc

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Mechanisms underlying rhythmic locomotion: body–fluid interaction in undulatory swimming

Mechanisms underlying rhythmic locomotion: body–fluid interaction in undulatory swimming

Our results on leech swimming, based on the simple fluid force model and experimental kinematic data, are consistent with the previous results on anguilliform swimming. Fig.11 shows that the thrust is generated continuously along the body, linearly increasing in magnitude toward the tail, as previously predicted (Muller et al., 2001). The head region experiences most of the drag. The vertically pointed fluid force vectors shown in Fig.10 predict that the wake consists of jets normal to the swimming direction, leading to a pair of vortices. This corresponds to the lateral jets observed in eel swimming (Tytell and Lauder, 2004) because the undulation occurs in a vertical plane for leeches. Moreover, the force vector has a large magnitude at the tail link, consistent with the observation that large lateral jets are generated near (but just anterior to) the tail tip (Tytell and Lauder, 2004). Thus, our simple model appears to capture the essence of the hydrodynamic forces exerted on the body during undulatory swimming. At the same time, the consistency with previous results on eels indicates that the mechanisms underlying leech swimming are similar to anguilliform swimming in spite of the lack of fins in leeches.

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The Influence of Additional Surface on Force Platform’s Ground Reaction Force Data During Walking and Running

The Influence of Additional Surface on Force Platform’s Ground Reaction Force Data During Walking and Running

Abstract: This study compares the vertical ground reaction force exerted from walking and running movement on two different surfaces of a force platform. Five skilled male futsal players were recruited to perform the walking and running tasks over the force platform. In the first setting, the players moved directly in contact with the force platform’s bare surface while in the second setting, the players performed the same tasks on the force platform covered with a typical futsal pitch surface material. The force from the peak heel and peak forefoot strikes were recorded and used for further analysis. A paired t-test was conducted for comparison and the results indicated that there are no significant differences between the two force platform conditions in terms of the magnitude of peak heel strike and peak forefoot strike forces during walking and running. Results also showed that there is a significant difference (p<0.05) on the ratio of the heel and forefoot strike peak force during walking task (1.05 in force platform bare surface, 0.99 in force platform + futsal court surface). While the data obtained in this study suggests that an additional surface on the force plate has no significant effect on the magnitudes of vertical ground reaction force data, there were indeed some changes that occurred on the heel/forefoot strike force ratio in walking task. The result might suggest that an additional surface (futsal court material) on the force platform has some impacts on the movement pattern of the foot during walking task due to the different conditions of the shoe’s outsole-flooring surface interaction.

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Static Testing of Draft Sensor for Three Point Hitch Dynamometer Utilization

Static Testing of Draft Sensor for Three Point Hitch Dynamometer Utilization

When the shear stress is occurred at the dra sensor, magnetoelastic eff ect is performed. In non-load condition, symmetrical magnetic fi eld is formed. Voltage output in this case fl uctuates around 5 V in all angular orientations. During the loading in zero position, signifi cant voltage change is recorded. Voltage drop from 5 V to 3.16 V persists and at maximum load voltage diff erence of 1.9 V is reached. With angle increase, voltage output sensitivity declines up to minimum in case of 90° angular position. This phenomenon was observed also in angular range from 0° to −90°. There is evident voltage output symmetry along X axis which corresponds with longitudinal axis of tractor. Similar behavior of the dra sensor was expected because the resultant and tractor pull power force are located in longitudinal direction. During the loading in 180° position signifi cant voltage change appears. Voltage upsurge from 5 V to 7.06 V occurs

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Search Engine Optimization (SEO): Technical Analysis Concepts

Search Engine Optimization (SEO): Technical Analysis Concepts

Back-Link campaign effectively, may act as a super booster to your incoming traffic, net visibility, high page rankings and top listing among the major important search engines on the very keyword(s) / phrase(s) to intend to hit high on. Back- Links are confirmed by making many webmasters share / trade their site‟s links with other webmasters interested in the same. Search Engine List offers you links to search engines and directories from all around the world to help you achieve top search engine ranking. Make your own website submissions.

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Design Considerations on a Flexible Membrane Tsunami Flood Barrier

Design Considerations on a Flexible Membrane Tsunami Flood Barrier

The choice of the most attractive values of the value f is less simple. The low values of f are related to larger membrane contour lengths, so to higher membrane costs. The membrane cost factor at the lowest f-values is about 1.5 times that at the higher f-values. On the other hand, the vertical force component at the top is also highly de- pendent on f. especially in the lower region. So accepting somewhat higher membrane costs will result in consid- erably smaller floaters. For α = 0.2, the studied f-values show a range of about a factor 6 regarding the vertical force component. This factor may be more important than the factor 1.5 on the membrane costs. However, final judgment requires considering the consequences of the vertical force component and the required floater size in more detail. The upper line in Table 1 (α = 0.2; f = 0.745) is chosen as an example. The required membrane related floater force is 72 kN/meter for this situation. Assume a cylindrical floater (cylinder axis along the top of the membrane) with a diameter of 3 meter. The vol- ume is than 3 2 π/4 m 3 per meter length. Assuming that

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Ultimate structural and fatigue damage loads of a spar-type floating wind turbine

Ultimate structural and fatigue damage loads of a spar-type floating wind turbine

Firstly, we examine the dynamic structural responses, which are the basis of the evaluation of ultimate and fatigue damage loads. Figure 5 plots the tower base bending moment histories in Case2. Due to the wind turbine thrust force, the mean value is non- zero. It implies that the ultimate structural load is more likely to exceed a certain level when subject to large wind force. Besides, the obvious fluctuating component is observed. Therefore, the ultimate structural load is determined by both aerodynamic and hydrodynamic excitations. Figure 6 shows the power spectrum density of the tower base

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Low Cost Housing Using Pre-Tensioned Precast Concrete Elements

Low Cost Housing Using Pre-Tensioned Precast Concrete Elements

This test was aimed to determine the tensile strength of given specimen of wire and to plot the stress strain curve to study the effect of tensile loading. To evaluate mechanical properties of material in an initial period, tensile test is most useful information about yield strength ultimate tensile strength for locally available wire. Stress-strain diagram shows the performance of tested material by graphically expressing the stress exerting in the specimen as a function of strain of pulling action of the Universal Testing Machine (UTM) from the start of pulling to the occurrence of failure. During the test force and the matching deformation were recorded. The extended length at any point of loading is original length plus the elongation. The typical results of the test for 4 mm diameter wire are presented in Table 1 and the stress strain curve is plotted as Figure 1.

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Curative Pooling When the Validity of an Oil and Gas Lease Is Challenged (Force Pooling the Top Lessee)

Curative Pooling When the Validity of an Oil and Gas Lease Is Challenged (Force Pooling the Top Lessee)

The Commission entered a pooling order in February of 2001, covering the workover of the existing well, including a deepening and recompletion of the existing well. Base Lessee appeared before the Commission in such cause. Base Lessee filed a motion to reopen and “correct” the pooling order to allow for “deferred payment of cost for formations currently behind pipe in the…well.” 36 Base Lessee desired to participate in the recompletion aspect of the operations, but not in the deepening of the well to other formations. Base Lessee withdrew its request after entering into a letter agreement dated April 4, 2001, with Top Lessee and Operator. Under the letter agreement, Base Lessee would be allowed to defer prepayment of well costs under the pooling order until Operator and Top Lessee were ready to complete the well in the shallower zones. The letter agreement further stipulated that Operator and Top Lessee did not admit the validity of the base leases or that the Base Lessee owned any interest at all. Base Lessee elected to participate under the pooling order, as supplemented by the obligations of the letter agreement. 37

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Construction Sequence Analysis of Multistoried RCC Building

Construction Sequence Analysis of Multistoried RCC Building

Bending moment in the construction sequence analysis is more at first story which is 322.132 KN-m in external column and it is going to be decreased as the story level increases hence at the end of total height the story the value is -35.1156 KN-m. The bending moment in linear static analysis is less as compared to construction sequence analysis which is 114.9895 KN-m at first story and decreased at top story having bending moment -15.8139 KN-m. From these results it is found that the bending moment is also more in support when RC frame is analysed by construction sequence manner than linear static manner. Hence construction sequence analysis should take in consideration.

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Friction Force in the Pneumatic Cylinder

Friction Force in the Pneumatic Cylinder

The results that show the dependence of friction force on piston velocity are presented in Fig. 2. They are valid for conditions in the cylin­ der when the value of relative pressure is zero and the grease INT 436, added at the assembly of the cylinder, is used as a lubricant. The air used in the cylinder is dry and unoiled. The friction force at different velocities lies in the range between 160 and 260 N. The curve is similar to the Stribeck’ s curve and such dependence of friction force on velocity can also be found in some papers dealing with these problems 111, [31, [51, [71, 1131.

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