Visual estimation of the force applied by another person

As observers, we believe that we can visually estimate the force that another person applies to an object. However, it is unclear what kind of cues we use to do this. We have focused on two types of visual change that occur when a person pushes an elastic object from above with his or her finger: the first one relates to a finger/hand shaking, known as an ``induced tremor'' and the second one relates to object deformation due to the application of force. This study shows that human observers of videos combine these two visual cues to estimate the force being applied by another person in the videos. Overall, the apparent force was stronger when the shaking was larger and when the magnitude of the deformation was larger, although systematic individual differences existed. The estimation of force was likely made in separate cognitive functions from the estimation of object softness. Estimating the force that another person applies seems to be done by perceptually interpreting both the actions of others and their external outcomes.

Numerical and Experimental Study on Optimization of Coil Springs used in Vehicles’ Suspension System

In general, the suspension systems are used to absorb vibrations, bump, rolls, dip from shock loads due to road surface irregularities. It performs its major role without affecting the vehicles’ stability and overall handling during operation. Coil springs are used as suspension element in light vehicles to attenuate unwanted vibrations. A spring is an elastic object used to store mechanical energy and it can be twisted, pulled or extended by some force and can return to its initial position when the force is released. In this study, mild steel material was taken into consideration in designing and fabricating coil springs. Theoretical and experimental investigations were conducted to calculate springs’ stiffness and to make validation between them. Three model of springs having coils 10, 11, 14 respectively are designed which have slight stiffness difference both theoretically and experimentally. The models were analyzed to determine mechanical behaviors for randomly chosen loading conditions ranging from 29.4 N to 176.4 N which are better suited with spring size. It is noted from both numerical and experimental investigations that deflection is high when the stiffness is less and vice-versa. In addition, shear stress formation increases with the increment of stiffness and applied load. Hence, springs having high stiffness are used in suspension system to reduce vibration and other disturbances. This study shows springs of having high stiffness are comparatively compact in size and cost economic as well.

PUT-Hand—Hybrid Industrial and Biomimetic Gripper for Elastic Object Manipulation

In this article, the design of a five-fingered anthropomorphic gripper is presented specifically designed for the manipulation of elastic objects. The manipulator features a hybrid design, being equipped with three fully actuated fingers for precise manipulation, and two underactuated, tendon-driven digits for secure power grasping. For ease of reproducibility, the design uses as many off-the-shelf and 3D-printed components as possible. The on-board controller circuit and firmware are also presented. The design includes resistive position and angle sensors in each joint, resulting in full joint observability. The controller has a position-based controller integrated, along with USB communication protocol, enabling gripper state reporting and direct motor control from a PC. A high-level driver operating as a Robot Operating System node is also provided. All drives and circuitry of the PUT-Hand are integrated within the hand itself. The sensory system of the hand includes tri-axial optical force sensors placed on fully actuated fingers’ fingertips for reaction force measurement. A set of experiments is provided to present the motion and perception capabilities of the gripper. All design files and source codes are available online under CC BY-NC 4.0 and MIT licenses.

A Time-independent Deformer for Elastic-rigid Contacts

We introduce a new tool that assists artists in deforming an elastic object when it comes in intersection with a rigid one. As opposed to methods that rely on time-resolved simulations, our approach is entirely based on time-independent geometric operators. It thus restarts from scratch at every frame from a pair of objects in intersection and works in two stages: the intersected regions are first matched and a contact region is identified on the rigid object; the elastic object is then deformed to match the contact while producing plausible bulge effects with controllable volume preservation. Our direct deformation approach brings several advantages to 3D animators: it provides instant feedback, permits non-linear editing, allows for the replicability of the deformation in different settings, and grants control over exaggerated or stylized bulging effects.

ELASTIC OBJECT DESIGNING FOR THE RESEARCH OF THE OPTIMAL PORTABLE ROTATIONAL MOTION AROUND FIXED AXIS

Many types of manipulators, operating in terrestrial conditions and, especially, in a state of weightlessness, require a significant reduction in mass, which leads to a decrease in the rigidity of structural elements and a change in the spectrum of natural vibration frequencies. Problems of manipulators' mass minimizing are still relevant. Besides, limitations on strength and rigidity should be taken taking into account. It is given the solution of the problems of mass minimizing with the analysis of possible compensation of displacements and the use of additional impacts.

Active vibration suppression of Bernoulli–Euler beam: experiment and numerical simulation

In order to design the most effective systems of vibration control of a distributed elastic object, it is necessary to have a model of this object, which would allow one to obtain the control results numerically without experiment. This gives an opportunity to compare the results of different control systems with each other and choose the most efficient ones. The paper is concerned with numerical simulation of the results of experimental study on suppression of forced vibrations of a cantilever metal beam with piezoelectric sensors and actuators by finite element method. The new designed control systems are based upon the results of numerical simulation and turn out to be more effective than those tested in the experiment. The numerical results previously received for modal control systems were significantly improved by using the optimization procedure, which allows one to select the optimal parameters of the filters used in the feedback loops of the designed control systems.

Parameters Synthesis of the Shock Absorber System for an Elastic Object with Incomplete Data on Stochastic External Loads

The elastic object and the deprecation system are described by a system of nonlinear ordinary differential equations. Probabilistic characteristics of external influence are not define. According the guaranteed result method it can be any of a finite set of deterministic realizations. Optimizing the parameters of the passive depreciation system reduces to solving a minimax multicriteria problem. The depreciation parameters can vary in a given class without introducing additional restrictions. To calculate the extremum of the objective function, the search algorithm of the Nelder-Mead deformable polyhedron is used. The results are illustrated by an example.