Experimental study of relationship between interfacial electroadhesive force and applied voltage for different substrate materials

Abstract

An experimental investigation into the relationship between the interfacial electroadhesive force and applied voltage up to 20 kV has been presented. Normal electroadhesive forces have been obtained between a double-electrode electroadhesive pad and three optically flat and different substrate materials: glass, acrylic, and polycarbonate. The results have shown that not all substrate materials are good for the generation of electroadhesive forces. Only 15.7 Pa has been obtained between the pad and the polycarbonate substrate under 20 kV, whereas 46.3 Pa and 123.4 Pa have been obtained on the acrylic and glass substrate, respectively. Based on the experimental data, empirical models, with an adjusted R-square value above 0.995 in all cases, have been obtained for the three substrates. However, it has not been possible to develop a general empirical model which is suitable for all substrates. This further indicates the need for a large quantity of experimental data to obtain robust empirical models for different substrate materials in order to reliably use electroadhesive technologies for material handling applications.

Symmetrical electroadhesives independent of different interfacial surface conditions

“…19 In addition, there was a relative difference of 75.3% for a polyimide comb electroadhesive pad when energized at 4.4 kV and exposed to the four surface scratch directions. 11 Note that the relative difference was defined here as: (maximum value À minimum value)/minimum value  100%.…”

“…Previous results demonstrated that: (1) the rougher the substrate surface, the smaller the electroadhesive force would be, to some extent 11 (this is because the decreasing contact areas and the increasing air inclusion and distance between the electroadhesive and the substrate cause a force reduction); (2) unstable adhesive forces would be obtained using both double-electrode and comb pad designs under different substrate surface conditions and the same substrate with differing surface scratch directions. 11,19 It is assumed that spiral and concentric electroadhesive pad designs can be independent of different interfacial surface interactions, thus producing stable adhesive forces on the same plate with different interfacial surface conditions. In order to verify this, a circular aluminium (Al) plate (thickness of 1 mm and diameter of 275 mm) was sanded by a 60 grit aluminium oxide sanding disc to produce a unidirectional surface scratch.…”

“…17 They were also tested using the electroadhesive "normal force" testing platform and procedure published previously. 11,19 In order to eliminate the effect of the dielectric thickness and surface texture on the adhesive force obtainable, during the tests, the PET side of the pads was used to face the Al substrate. Note that in order to show that the thickness and surface texture of the PET side of the copper laminate are relatively consistent, surface texture and thickness measurements of five completely etched and cleaned copper laminates were conducted.…”

Experimental study of a flexible and environmentally stable electroadhesive device

“…8 Electroadhesion is an electrically controllable and dynamic 8 electrostatic attraction between an electroadhesive pad and a substrate, with 33 variables influencing the interfacial electroadhesive force. 9 These variables include voltage 10,11 and material properties such as relative permittivity, [10][11][12] pad geometry, 13,14 surface texture, 15 and environmental conditions. 9,16 A typical electroadhesion system contains four main parts, including an electroadhesive pad, a power supply, a control system, and a substrate, as can be seen in Fig.…”

“…9,10 The force tests were conducted over three days, and each test was repeated five times. A 15-time test was conducted previously to check the repeatability of the testing procedure and concluded that five times were enough to produce robust and repeatable results.…”