Norhashim Mohd Arshad

Construction sonar sensor model of low altitude field mapping sensors for application on a UAV

Creating a two dimensional (2D) map required a suitable position and orientation of ultrasonic sensors which must be primarily determined. The series of ultrasonic sensors are used for low-altitude mapping on pre-determined plane. A pre-determined angle must be known and calculated before it is used in the mapping. Experiment was conducted on a model with a height of 160 cm from the ground surface. Reflective sound waves that were produced from the sensors had been experimented and analyzed to cover a constructed plane. Data from the sensors was analyzed and processed to create a virtual map that nearly similar as the real pre-determined plane. The experimental results were also tested in the real environment.

Single infra-red sensor technique for line-tracking autonomous mobile vehicle

Floor-based line-tracking technique is widely implemented for use in many autonomous mobile vehicle applications in the industries such as for transportation of goods within an enclosed warehouse or factories. It is also popular in competition robots. Many line-tracking systems utilize several kinds of discrete sensors such as the reflective infra-red LED, light dependent resistor (LDR), and multi-array inductance. Multiple of these discrete sensors are required to be arranged closed together in front of the vehicle and facing the floor to trace the profile of the line. A minimum of two sensors are required to ensure effectiveness of the line detection algorithm, especially to determine the vehicles position, either at left or at right with respect to line. This paper proposed a latest idea of using only one discrete sensor for mobile vehicle to detect a line having two colour shades on a white background surface. The results show that single sensor managed to allow the vehicle to maneuver as effectively on the line.

Fractional-order PI controller with relay auto-tuning method

Fractional-order PID (FOPID) controller has been proven to provide better performance compared to the classical PID by many researchers. So far, the implementation of FOPID especially in the tuning aspect had become an interesting topic in this area. Thus, this paper presents a simple but practical approach in tuning of fractional-order PI (FOPI) controller using relay method. This method is convenient when the process model cannot be determined accurately. Furthermore, it gives clear insight on the input-output response and hence, produced better results within the specified constraints. The FOPI controller was compared with the PI using the same settings on real-time steam temperature control. The FOPI has to be cascaded to an error filter to achieve faster output convergence. This issue was explained in the paper. Both PI and FOPI controllers were subjected to set-point change and load disturbance tests. Integral of squared error (ISE) and Integral of Control (ICO) signal indices indicate the superiority of FOPI over the classical PI.

Vision-based detection technique for effective line-tracking autonomus vehicle

An alternative means of implementing line detection technique to navigate autonomous mobile vehicles was investigated, specifically using vision sensor as the front end detection device. A vision sensor has the advantages of much higher spatial and optical resolutions as compared to the conventional discrete photo-reflective sensors used in most line-following mobile vehicles. It could offer better detection accuracy and reliability in varying lighting conditions. A selective video line technique was introduced and implemented which resulted in reduced number of video lines needs to be processed. Hence, avoiding the needs to use high-end processor to process and analyze the vast amount of information from the video images. There was enough space of information from each video line signal to be manipulated and could easily and flexibly calibrated with several lighting conditions. Abrupt changes in ambient lighting can be overcome without affecting the accuracy of the mobile vehicle navigation. A small inexpensive analog video camera, with standard video output signal had been chosen with a decent 8-bit microcontroller to process the video line signals and navigate the mobile vehicle.

Steam temperature regulation with self-tuning PID based on pole-assignment method

An explicit self-tuning PID control was designed using pole-assignment method to regulate steam temperature of a steam distillation for essential oil extraction process. Online parameter estimation was involved and implemented using Recursive Least Square (RLS) method with directional forgetting. The controller performance was evaluated by simulation on second-order model identified from the process step response. Extensive analysis was done to understand the effect of the desired poles location towards the controlled variable. Optimum desired poles for steam temperature process were 0.9 for α and 0.1 for ω. The controller was able to regulate the steam temperature and also robust in the presence of disturbance.

Design and experimental study of fuzzy PI λ D μ with error filter

Fractional-order PID (FOPID) control is currently an emerging topic in control engineering research. The controller was proven to perform better than the integer-order controller because of the generalization in the integrator and differentiator power. But lately, the application has been widened into non-PID type controllers including fuzzy rules application. The application of fuzzy can accommodate the tuning of PID gain for a non-linear process such as steam temperature. This study initiates the design of self-tuning fuzzy for FOPID controller that will automatically select the PID gains while the fractional-order was fixed. The proposed technique, named fuzzy FOPID was compared with the fuzzy PID for set point change and load disturbance test. The fuzzy FOPID controller was further improved by applying an error filter to the integrator to minimize overshoot and dampened fluctuations around the set point. The proposed fuzzy FOPID with error filter was proven to provide better control with less error index and control effort measured by Integral of Squared Error and Integral of Control signal.

Quality assessment of citronella oil with regulated extraction temperature

This study analyzed the effect of temperature during steam distillation extraction on the essential oil quality. An improvised steam distillation system was applied for Cymbopogon nardus extraction with the capability to regulate the steam temperature at any desired value. The quality was evaluated using refractive index and GC-MS analysis. The results were compared with the international standard for citronella oil (BS ISO 3849:2003) and against the data gathered from literatures. The chemical compounds are much differed from literatures but complied with the minimum requirements from the ISO standard. Nonetheless, quality improvement of the yield can be observed between each sample from different temperature settings.