A closed-form solution to eye-to-hand calibration towards visual grasping

Author(s):  
Hui Pan ◽  
Na Li Wang ◽  
Yin Shi Qin

Purpose – The purpose of this paper is to propose a method that calibrates the hand-eye relationship for eye-to-hand configuration and afterwards a rectification to improve the accuracy of general calibration. Design/methodology/approach – The hand-eye calibration of eye-to-hand configuration is summarized as a equation AX = XB which is the same as in eye-in-hand calibration. A closed-form solution is derived. To abate the impact of noise, a rectification is conducted after the general calibration. Findings – Simulation and actual experiments confirm that the accuracy of calibration is obviously improved. Originality/value – Only a calibration plane is required for the hand-eye calibration. Taking the impact of noise into account, a rectification is carried out after the general calibration and, as a result, that the accuracy is obviously improved. The method can be applied in many actual applications.

2004 ◽  
Vol 17 (1) ◽  
pp. 41-52
Author(s):  
Zoran Velkov-Hadzi ◽  
Boris Spasenovski

In this paper, we examined the influence of capture effect with L-fold antenna diversity at the Access Point over IEEE 802.11b DCF. We obtained an exact closed-form solution for the conditional capture probability in case of ideal selection diversity, and an approximate closed-form solution for the conditional capture probability in case of maximum selection diversity in a Rayleigh-faded channel. Obtained analytical expressions have general significance and can be applied for any other multiple access wireless network. We also analytically evaluated saturation throughput increase of the IEEE 802.11b DCF protocol exposed to capture.


This study obtains a closed-form solution for the discrete-time global quadratic hedging problem of Schweizer (1995) applied to vanilla European options under the geometric Gaussian random walk model for the underlying asset. This extends the work of Rémillard and Rubenthaler (2013), who obtained closed-form formulas for some components of the hedging problem solution. Coefficients embedded in the closed-form expression can be computed either directly or through a recursive algorithm. The author also presents a brief sensitivity analysis to determine the impact of the underlying asset drift and the hedging portfolio rebalancing frequency on the optimal hedging capital and the initial hedge ratio.


Author(s):  
Shahab Mansoor-Baghaei ◽  
Ali M. Sadegh

Spherical shells have been employed to model impacts to human heads; however, an ellipsoidal shell is that is more realistic model of the head has not fully investigated. In this paper, impact of an elastic ellipsoidal shell with an elastic flat half space is analytically analyzed and a closed-form solution is derived which led to a complex differential equation. Due to the complexity of the impact equation it could not be solved by standard solutions. Therefore, the Newtonian method and a linearization scheme are employed to simplify this equation in order to obtain the response of the impact problem and the closed-form solution. The analytical solutions are validated by finite element method. Good agreement between the closed form solution and the FE results is observed. To show the difference, the ellipsoidal solutions are also compared to the spherical solutions. To the best of our knowledge, this method and its closed-form solution have not been addressed in the literature. It is concluded that the closed-form solution is trustworthy and can be used to investigate the impact of the skull (as an elastic ellipsoidal shell) with a rigid or elastic plate, including the skull deformation and parametric studies. This solution could be expanded to include the brain materials inside the ellipsoidal shell.


2021 ◽  
Vol 2 (1) ◽  
pp. 41-50
Author(s):  
Masoud Goharimanesh ◽  
◽  
Ali Koochi ◽  

This paper deals with investigating the nonlinear oscillation of carbon nanotube manufactured nano-resonator. The governing equation of the nano-resonator is extracted in the context of the nonlocal elasticity. The impact of the Casimir force is also incorporated in the developed model. A closed-form solution based on the energy balance method is presented for investigating the oscillations of the nano-resonator. The proposed closed-form solution is compared with the numerical solution. The impact of influential parameters including applied voltage, Casimir force, geometrical and nonlocal parameters on the nano resonator’s vibration and frequency are investigated. The obtained results demonstrated that the Casimir force reduces the nano-resonator frequency. However, the nonlocal parameter has a hardening effect and enhances the system’s frequency.


2015 ◽  
Vol 82 (4) ◽  
Author(s):  
Shahab Mansoor-Baghaei ◽  
Ali M. Sadegh

In this paper, a closed form solution of an arbitrary oriented hollow elastic ellipsoidal shell impacting with an elastic flat barrier is presented. It is assumed that the shell is thin under the low speed impact. Due to the arbitrary orientation of the shell, while the pre-impact having a linear speed, the postimpact involves rotational and translational speed. Analytical solution for this problem is based on Hertzian theory (Johnson, W., 1972, Impact Strength of Materials, University of Manchester Institute of Science and Technology, Edward Arnold Publication, London) and the Vella’s analysis (Vella et al., 2012, “Indentation of Ellipsoidal and Cylindrical Elastic Shells,” Phys. Rev. Lett., 109, p. 144302) in conjunction with Newtonian method. Due to the nonlinearity and complexity of the impact equation, classical numerical solutions cannot be employed. Therefore, a linearization method is proposed and a closed form solution for this problem is accomplished. The closed form solution facilitates a parametric study of this type of problems. The closed form solution was validated by an explicit finite element method (FEM). Good agreement between the closed form solution and the FE results is observed. Based on the analytical method the maximum total deformation of the shell, the maximum transmitted force, the duration of the contact, and the rotation of the shell after the impact were determined. Finally, it was concluded that the closed form solutions were trustworthy and appropriate to investigate the impact of inclined elastic ellipsoidal shells with an elastic barrier.


Author(s):  
Sivadol Vongmongkol ◽  
Asgar Faal-Amiri ◽  
Hari M. Srivastava

Crushable material has widely been used as an engineering solution for energy absorption devices among many industries. Abnormal and severe accident loads in the design of nuclear power plants are required to be addressed in order to comply with Nuclear Regulatory Commission (NRC) requirements which makes the crushable material more suitable in its highly dynamic application. One of the severe loads is from a postulated high energy piping system rupture. Its effects are required to be mitigated so that the proper operation of safety related systems, structures and components (SSC) of these facilities is assured. The postulated pipe rupture loads are among the highest loads that need to be addressed in the design process of nuclear power plants. The impact forces produced by the postulated pipe rupture are typically being absorbed by energy absorption devices called “Pipe Whip Restraints” in which the restraints can minimize the loads affecting the SSCs to within an acceptable limit. This paper provides a simplified closed-form solution to determine the energy absorbing characteristic that will help to design these devices. This paper will also provide a comparison between results of the proposed simplified closed-form solution equations to the experimental test results and the calculated results using finite element analysis.


2019 ◽  
Vol 15 (4) ◽  
pp. 800-817
Author(s):  
Makram Elfarhani ◽  
Ali Mkaddem ◽  
Saeed Rubaiee ◽  
Abdessalem Jarraya ◽  
Mohamed Haddar

Purpose The purpose of this paper is to cover an experimental investigation of the impulse response of the foam-mass system (FMS) to unveil some of the foam dynamic behavior features needed to optimize the impact comfort of seat-occupant system. The equation of motion of the studied system is modeled as a sum of a linear elastic, pneumatic damping and viscoelastic residual forces. An identification methodology based on two separated calibration processes of the viscoelastic parameters was developed. Design/methodology/approach The viscoelastic damping force representing the foam short memory effects was modeled through the hereditary formulation. Its parameters were predicted from the free vibrational response of the FMS using iterative Prony method for autoregressive–moving–average model. However, the viscoelastic residual force resulting in the long memory effects of the material was modeled with fractional derivative term and its derivative order was predicted from previous cyclic compression standards. Findings The coefficients of the motion law were determined using closed form solution approach. The predictions obtained from the simulations of the impulse and cyclic tests are reasonably accurate. The physical interpretations as well as the mathematical correlations between the system parameters were discussed in details. Originality/value The prediction model combines hereditary and fractional derivative formulations resulting in short and long physical memory effects, respectively. Simulation of impulse and cyclic behavior yields good correlation with experimental findings.


2015 ◽  
Vol 75 (1) ◽  
pp. 47-62 ◽  
Author(s):  
Lin Sun ◽  
Calum G. Turvey ◽  
Robert A. Jarrow

Purpose – The purpose of this paper is to outline a pricing formula for the valuation of catastrophic (CAT) bonds as applied to multiple trigger drought risks in Kenya. Design/methodology/approach – The valuation model is designed around the multiple triggers of the Mexican Catastrophe bonds, but the valuation model is based on Jarrow’s (2010) closed form CAT Bond Pricing model. The authors outline the model structure, the multiple tranches with rainfall triggers, and simulate the model using Monte Carlo methods. Data input was synthesized from historical rainfall data in Kenya’s Moyale region as well as prevailing LIBOR and rates and conventional coupons. Findings – The authors compute the valuation model using Monte Carlo techniques. The authors found the pricing method to be robust and consistent under various parameter settings including trigger levels, time after launch, recovery rates, coupon spreads, and zero coupon curves. For example the higher the trigger rates, the lower will be the bond price at issue. With 50 percent recovery the CAT bond at issue would be around $702 with a high triggers and 976 with low triggers, but the valuation changes with parameters. Practical implications – As far as the authors know the use of multiple trigger CAT bonds has been very limited in practice. The valuation formula and methods outlined in this paper show how CAT bonds can be effectively designed to address CAT covariate risks in developing agricultural economies. Originality/value – This paper examines CAT bonds to investigate multi-trigger rainfall risks in Kenya. The paper shows how CAT bonds can be designed to meet specific and CAT risks. Using Jarrow’s (2010) closed form solution this paper is one of the first to apply it to the macro-management of agricultural risks.


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