Muhammad Ilhamdi Rusydi

Affine Transform to Reform Pixel Coordinates of EOG Signals for Controlling Robot Manipulators Using Gaze Motions

Biosignals will play an important role in building communication between machines and humans. One of the types of biosignals that is widely used in neuroscience are electrooculography (EOG) signals. An EOG has a linear relationship with eye movement displacement. Experiments were performed to construct a gaze motion tracking method indicated by robot manipulator movements. Three operators looked at 24 target points displayed on a monitor that was 40 cm in front of them. Two channels (Ch1 and Ch2) produced EOG signals for every single eye movement. These signals were converted to pixel units by using the linear relationship between EOG signals and gaze motion distances. The conversion outcomes were actual pixel locations. An affine transform method is proposed to determine the shift of actual pixels to target pixels. This method consisted of sequences of five geometry processes, which are translation-1, rotation, translation-2, shear and dilatation. The accuracy was approximately 0.86° ± 0.67° in the horizontal direction and 0.54° ± 0.34° in the vertical. This system successfully tracked the gaze motions not only in direction, but also in distance. Using this system, three operators could operate a robot manipulator to point at some targets. This result shows that the method is reliable in building communication between humans and machines using EOGs.

Rotation Matrix to Operate a Robot Manipulator for 2D Analog Tracking Objects Using Electrooculography

Performing some special tasks using electrooculography (EOG) in daily activities is being developed in various areas. In this paper, simple rotation matrixes were introduced to help the operator move a 2-DoF planar robot manipulator. The EOG sensor, NF 5201, has two output channels (Ch1 and Ch2), as well as one ground channel and one reference channel. The robot movement was the indicator that this system could follow gaze motion based on EOG. Operators gazed into five training target points each in the horizontal and vertical line as the preliminary experiments, which were based on directions, distances and the areas of gaze motions. This was done to get the relationships between EOG and gaze motion distance for four directions, which were up, down, right and left. The maximum angle for the horizontal was 46°, while it was 38° for the vertical. Rotation matrixes for the horizontal and vertical signals were combined, so as to diagonally track objects. To verify, the errors between actual and desired target positions were calculated using the Euclidian distance. This test section had 20 random target points. The result indicated that this system could track an object with average angle errors of 3.31° in the x-axis and 3.58° in the y-axis.

Real-time measurement of grid connected solar panels based on wireless sensors network

The paper presents real-time measurement of grid connected photovoltaic system using Zigbee sensors networks. The measurements were performed using sensors that chosen based on their simplicity and lower price. The weather parameters were measured using OPT101 photodiode for irradiance sensors and DHT22 for temperature and humidity sensors. While low cost ACS 712 5A current sensor and Arduino voltage sensor modules were used to measure PV output current and voltage. The 1.25 kWp grid connected PV system were used to test the real-time measurement system. The data received exactly same as sensed data that sent from remote area with time delay around 3 to 4 seconds. The solar panels in average have produced power twelve hours per day for clear sky, however for raining, overcast and cloud covered sky, PV power decreased and grid disconnected earlier before sunset and the PV power curve show an irregular profile. Experimental results demonstrate that real-time PV data can be recorded using Zigbee sensors network. This information can be used as a further reference for performance and energy saving analysis of PV system installed in West Sumatera.