A low-cost, human-like, high-resolution, tactile sensor based on optical fibers and an image sensor

Abstract

Tactile sensors are commonly a coordinated group of receptors forming a matrix array meant to measure force or pressure similar to the human skin. Optic-based tactile sensors are flexible, sensitive, and fast; however, the human fingertip's spatial resolution, which can be regarded as the desired spatial resolution, still could not be reached because of their bulky nature. This article proposes a novel and patented optic-based tactile sensor design, in which fiber optic cables are used to increase the number of sensory receptors per square centimeter. The proposed human-like high-resolution tactile sensor design is based on simple optics and image processing techniques, and it enables high spatial resolution and easy data acquisition at low cost. This design proposes using the change in the intesity of the light occured due to the deformation on contact/measurement surface. The main idea is using fiber optic cables as the afferents of the human physiology which can have 9 mm diameters for both delivering and receiving light beams. The variation of the light intensity enters sequent mathematical models as the input, then, the displacement, the force, and the pressure data are evaluated as the outputs. A prototype tactile sensor is manufactured with 1-mm spatial and 0.61-kPa pressure measurement resolution with 0-15.6 N/cm 2 at 30 Hz sampling frequency. Experimental studies with different scenarios are conducted to demonstrate how this state-of-the-art design worked and to evaluate its performance. The overall accuracy of the first prototype, based on different scenarios, is calculated as 93%. This performance is regarded as promising for further developments and applications such as grasp control or haptics.

Optimal control research on a manipulator’s combined feedback device by the variational method genetic algorithm radial basis function method

“…The variation method seeks the extremum function, which makes the functionals reach their maximum or minimum values. [19][20][21][22] State equations of the manipulator. According to sections Combined feedback control and Solution of the optimal trajectory by the variation method with feedback model, the state variables are set according to the below formula…”

“…The variation method seeks the extremum function, which makes the functionals reach their maximum or minimum values. 19 –22…”

Haptic Interfaces for Virtual Reality: Challenges and Research Directions

“…Factors such as spatial resolution also differ for each mechanoreceptor, as seen in Table 1. Mechanoreceptors with high spatial resolution can better detect physical stimuli that are closely spaced [74]. Similarly, this information can be used when developing haptic interfaces by leveraging areas with high spatial resolutions for more intricate and nimble physical stimulations.…”