A 3D-Printable Robotic Gripper Based on Thick Panel Origami

Origami has been a source of inspiration for the design of robots because it can be easily produced using 2D materials and its motions can be well quantified. However, most applications to date have utilised origami patterns for thin sheet materials with a negligible thickness. If the thickness of the material cannot be neglected, commonly known as the thick panel origami, the creases need to be redesigned. One approach is to place creases either on top or bottom surfaces of a sheet of finite thickness. As a result, spherical linkages in the zero-thickness origami are replaced by spatial linkages in the thick panel one, leading to a reduction in the overall degrees of freedom (DOFs). For instance, a waterbomb pattern for a zero-thickness sheet shows multiple DOFs while its thick panel counterpart has only one DOF, which significantly reduces the complexity of motion control. In this article, we present a robotic gripper derived from a unit that is based on the thick panel six-crease waterbomb origami. Four such units complete the gripper. Kinematically, each unit is a plane-symmetric Bricard linkage, and the gripper can be modelled as an assembly of Bricard linkages, giving it single mobility. A gripper prototype was made using 3D printing technology, and its motion was controlled by a set of tendons tied to a single motor. Detailed kinematic modelling was done, and experiments were carried out to characterise the gripper’s behaviours. The positions of the tips on the gripper, the actuation force on tendons, and the grasping force generated on objects were analysed and measured. The experimental results matched well with the analytical ones, and the repeated tests demonstrate that the concept is viable. Furthermore, we observed that the gripper was also capable of grasping non-symmetrical objects, and such performance is discussed in detail in the paper.

Effect of material thickness and reduction ratio on roughness transfer in skin-pass rolling to DC04 grade sheet materials

Purpose The last stage of the cold rolling process is skin-pass rolling and one of its most significant goals is to obtain appropriate topography on the surface of the sheet steel used extensively such as in automotive industry. The purpose of this paper is to investigate the effect of thickness change and various reduction ratios on roughness transfer of DC04 grade sheet material. Design/methodology/approach DC04 grade sheet materials with different reduction ratios and several thicknesses were subjected to skin-pass rolling process in the rolling equipment with a two-high roll. Some roughness parameters were determined as a result of roughness measurements from the surfaces of roughened sheet materials. Findings While the roughness transfer is higher in 1-mm thick material in reduction ratios up to 430 micrometers; in reduction ratios above 430 micrometers, it is higher for 1.5-mm thick materials. As the reduction ratio increases in DC04 grade sheet materials, the homogeneity of the roughness distribution in 1-mm thickness sheet material deteriorates, while the roughness distribution in 1.5-mm thickness sheet material is more homogeneous. Originality/value This paper demonstrates how material thickness and reduction ratio affect the roughness transfer in skin-pass rolling. The results obtained can be used by optimizing in manufacturing processes.

Effect of Deposition Voltage on Layer Thickness, Microstructure, Cu/Ni Sheet Resistivity of Deposition Results by Magnetic Field Electroplating Assisted Technique

The purpose of this research is to make the Cu/Ni thin layer as an alternative to basic RTD materials through electroplating methods assisted by magnetic fields. Electroplating was carried out with variation in deposition voltage ranging from 1 to 5 V. The results of this study indicate that the deposition voltage applied to the coating affects the thickness, sheet resistivity, and microstructure of the coating. Thickness increases with increasing deposition voltage. The diffraction intensity and crystal size tend to increase with increasing deposition voltage. The distance between Bragg planes after the coating is almost equal for all samples. The highest sheet resistivity was obtained in the coating sample with a 4-volt deposition voltage.

Experimental study on bending behaviour of aluminium-copper clad sheets in V-bending process

The bimetallic sheets are used in the industrial sheet metal products to meet the demands of multi-functionality. The bending behaviour of bimetallic sheet is contributed by individual layers of the sheet and it is entirely different from the monolithic material. In this study, V-bending experiments are carried out to understand the springback, bend force and thickness change of Al-Cu clad sheets. The effect of different parameters such as sheet thickness, sheet setting condition, die angle, die opening and punch radius have been investigated. The results indicated that springback is more for smaller die angle, wider die opening and larger punch radius. Increase in die angle, increase in die opening or decrease in punch radius decreases the bend force. The clad sheet thickens at Al/Cu setting condition whereas it thins at Cu/Al setting condition. This thinning or thickening of the sheet influences the springback and bend force.

Impact of Lorentz Force on Unsteady Bio Convective Flow of Carreau Fluid across a Variable Thickness Sheet with Non-Fourier Heat Flux Model

In this article, we examined the magnetohydrodynamic Cattaneo-Christov bio convective flow of Carreau liquid over a variable thickness sheet with irregular heat sink/source. The fluid motion is supposed to be time dependent and not turbulent. Firstly, proper transmutations are pondered to metamorphose the basic flow equations as ODE. The solution of these ODEs is procured by the sequential execution of R.K. and Shooting numerical treatments. The density of motile organisms, concentration, temperature and velocity distributions for dissimilar values of non-dimensional parameters are perused via graphs. Further, we analyzed the impact of same parameters on friction factor, local Nusselt number and the rate of mass transfer coefficients and presented in table. Results indicate that the distribution of the density of motile organisms is an increasing function of Peclet and Lewis numbers. Fluid velocity is proportional to the Weissenberg number. Also the space dependent heat sink/source parameters perform obligatory role in the mass and heat transport performance.

3D flow of Carreau polymer fluid over variable thickness sheet in a suspension of microorganisms with Cattaneo-Christov heat flux

Numerical study of three dimensional Carreau liquid flow with heat and mass transport features over a variable thickness sheet filled with microorganisms is analyzed. We considered the non-uniform heat sink or source and multiple slip effects. The governing non-linear partially differential expressions are developed into ordinary differential systems by using variable transformations. These expressions are solved numerically by using Runge-Kutta fourth order method connected with shooting methodology. A Parametric study is implemented to demonstrate the effects of Hartmann number, Prandtl number, Weissenberg number, Peclet number, chemical reaction and heat sink/source parameters on liquid velocity, temperature and concentration profiles. The quantities of physical interest are described within the boundary layer. From this analysis, we found that the magnetic parameter decrease the local Sherwood and local Nusselt numbers for both and cases. The constraint of chemical reaction enhances the mass transfer rate and decelerates the density of motile mass transfer rate. The space dependent and temperature dependent heat source/sink suppress the local Nusselt number.