Spring balance and elastic—the answer

A question on the forces in a spring balance when different loads are apllied and the balance is also stretched with an elastic band.

Catalogue of selected experimental plans

Summary There are many works in the literature on the construction of experimental plans based on weighing designs. Hence, it is useful to compile a catalogue of experimental designs with specific properties. In this work, we investigate the properties of experimental plans constructed using the matrices of spring balance weighing designs. Additionally, an even number of experimental objects is assumed. An overview of the construction methods of these designs and classes of design matrices with selected properties are given. The results make it possible to create a catalogue of experimental designs constructed on the basis of spring balance weighing designs.

Design of a seed implantation robot with counterbalance and soft tissue stabilization mechanism for prostate cancer brachytherapy

This article focuses on the topic of the structural design of surgical radioactive surgery robot for prostate cancer. To improve the weight-to-payload ratio of surgery robot end-effector, the energy consumption and stability of robot joint drive and reducing the displacement and deformation of needle insertion in soft tissue. This article discusses the new static torque balancing method and multi-needle insertion soft tissue stabilization mechanisms that may be used in previously articulated seed implantation robots. Compared with the existing balancing system schemes, we adopt the idea of mutual conversion of gravitational potential energy and elastic potential energy and establish a static balancing model. With preloaded displacement parameter of the spring α, the variable gravity torque balance of robot arm can be achieved. Torque and equivalent gravity balancing distribution with the spring balance system and the quantitative evaluation experiment were performed, and experiment results provide evidence that these spring balance devices can basically compensate the gravity torque of the robot arm. In addition, we used nonlinear spring–damper model to establish multi-needles insertion soft tissue force model. Then, a variable multi-needle insertion soft tissue stabilization device is designed with six working modes. The innovative design of this device is the use of the first four needles that are introduced simultaneously on either side of the midline. Initially completed displacement simulation of different numbers of needle insertion prostate tissue, experiment results indicate that multi-needle puncture mechanism could reduce prostate displacement in the y- or z-direction. By this method, the prostate may be fixed, thus this mechanism maybe reduces rotation of the prostate and enabling subsequent needles to be inserted accurately.

Selected Remarks on Highly D‑efficient Spring Balance Weighing Designs

Here, we consider new construction method of determining highly D-efficient spring balance weighing designs in classes in that D-optimal design does not exist. We give some conditions determining the relations between the parameters of such designs and construction examples.

pyGABEUR-ITB: A FREE SOFTWARE FOR ADJUSTMENT OF RELATIVE GRAVIMETER DATA

<p class="JUDUL">pyGABEUR-ITB (Python<em> GayaBEUrat Relatif – Institut Teknologi Bandung)</em> is a free and interactive software for adjustment of relative gravimeter data, developed based on Python programming language. pyGABEUR-ITB can adjust relative gravity measurements and provide reliable estimates for correcting instrument’s systematic errors, such as gravimeter drift. Furthermore, pyGABEUR-ITB can also detect possible outliers in the observations using the t-criterion method. Since pyGABEUR-ITB is using the weighted constraint adjustment, at least one fixed station is required accordingly. Relative gravimeter data around Palu-Donggala area (Central Sulawesi) observed by Center for Geodesy Control Networks and Geodynamics, Geospatial Information Agency, were used to test the performance of pyGABEUR-ITB. The processing results were then compared against those calculated using GRAVNET software. The comparisons show that both pyGABEUR-ITB and GRAVNET softwares statistically provide simillar results, with the total RMS value of about 5 mGal. In term of computer’s requirement, pyGABEUR-ITB can be excecuted under a computer with the following minimal requirements: x64 CPU, 1 GB memory and WINDOWS 7 OS. Finally, it is important to mention that pyGABEUR-ITB is recently suited to process the data from the gravimeter that adopts the principle of vertical spring balance. In the near future, pyGABEUR-ITB will be extended to be able to automatically adapt to various observation principles.</p><strong></strong>

A Highly D‑efficient Spring Balance Weighing Design for an Even Number of Objects

The problem of determining unknown measurements of objects in the model of spring balance weighing designs is presented. These designs are considered under the assumption that experimental errors are uncorrelated and that they have the same variances. The relations between the parameters of weighing designs are deliberated from the point of view of optimality criteria. In the paper, designs in which the product of the variances of estimators is possibly the smallest one, i.e. D‑optimal designs, are studied. A highly D‑efficient design in classes in which a D‑optimal design does not exist are determined. The necessary and sufficient conditions under which a highly efficient design exists and methods of its construction, along with relevant examples, are introduced.

Design Method of Spring Balance Mechanism Through Derivation of General Solution

The present study set out to devise a means of designing a spring-balance mechanism (hereinafter, a SBM) based on a general solution. The goal was to apply a general solution as a guideline for identifying the optimum design solution. A SBM is used to reduce the actuator output in the design of a mechanical device. As a result, the effect of gravity can be offset and energy-saving in operation can be realized. To date, however, SBMs have been designed on a trial and error basis, with a reliance on the designer’s knowledge or experience. Thus, in some instances, it may not be possible to identify a design solution that should, in theory, be achievable. To overcome this issue, this study examined the application of a general solution to the design of a SBM. Such a general solution would identify a solution space including viable design solutions. Subsequently, once a design that satisfies the general solution had been identified, a search could be made of all the design solutions within the solution space. First, the sequence whereby the general solution is used to identify a SBM design that satisfies the general solution, thus providing a guideline for the search action, is determined. Herein, the method used to identify this initial SBM design is presented. The devised method is based on the description of an energy-conservation formula that does not involve any trial and error. The proposed method incorporates a conventional method into the design solution, which can be derived when the conventional method cannot identify a design solution. As a result, a design method using a general solution for the design of an SBM is realized.