Sophan Wahyudi Nawawi

Development of a Two-Wheeled Inverted Pendulum Mobile Robot

The research on two-wheeled inverted pendulum (T-WIP) mobile robots or commonly known as balancing robots have gained momentum over the last decade in a number of robotic laboratories around the world. This paper describes the hardware design of such a robot. The objective of the design is to develop a T-WIP mobile robot to be used as flexible platform comprises of embedded unstable linear plant intended for research and teaching purposes. Issues such as selection of actuators and sensors, signal processing units, modeling and control scheme was addressed and discussed. The system is then tested using a well-known pole-placement state feedback controller to verify its functionality.

Takagi-Sugeno fuzzy modeling of a two-wheeled inverted pendulum robot

A two wheeled inverted pendulum TWIP mobile robot is an under-actuated mechanical system, which is inherently open-loop unstable with highly nonlinear dynamics. This property attracts the interest of researchers worldwide in recent years. This paper presents the development of a linearized model of the TWIP mobile robot based on its nonlinear dynamical model using Takagi-Sugeno T-S fuzzy modeling technique, which can allow the application of linear control techniques in analyzing and efficiently controlling such under-actuated nonlinear system. The complete nonlinear dynamical equations of motion of the TWIP mobile robot were first derived using Kanes Method. Based on the nonlinear dynamical equations of motion, a T-S fuzzy model of the TWIP robot was then developed using local approximation technique. To validate the proposed model, simulations study was carried out and the results show that the proposed model approximates the original nonlinear TWIP mobile robot in the pre-specified domains to certain degree of accuracy.

Controller Design for Two-wheels Inverted Pendulum Mobile Robot Using PISMC

The research on two-wheel inverted pendulum or commonly call balancing robot has gained momentum over the last decade in a number of robotic laboratories around the world. This paper deals with the modeling of 2-wheels Inverted Pendulum and the design of proportional integral sliding mode control (PISMC) for the system. The mathematical model of 2-wheels inverted pendulum system which is highly nonlinear is derived. The final model is then represented in state-space form and the system suffers from mismatched condition. A robust controller based on sliding mode control is proposed to perform the robust stabilization and disturbance rejection of the system. A computer simulation study is carried out to access the performance of the proposed control law.

A PI sliding mode tracking controller with application to a 3 DOF direct-drive robot manipulator

This paper deals with the tracking control of direct-drive (DD) robot manipulators. A robust proportional-integral (PI) sliding mode control law is derived for accurate tracking despite the highly nonlinear and coupled dynamics. It is shown mathematically that the proposed controller is capable of withstanding the expected variations and uncertainties present in the system. The performance of the proposed control law is evaluated by means of computer simulation studies on a 3 DOF revolute DD robot manipulator actuated with BLDCM motors.

Development of planar electromagnetic sensor array for nitrate and sulphate detection in natural water sources

Purpose – The purpose of this study is to determine the contamination level in natural water resources because the tremendous development in the agriculture sector has increased the amount of contamination in natural water sources. Hence, the water is polluted and unsafe to drink. Design/methodology/approach – Three types of sensor arrays were suggested: parallel, star and delta. The simulation of all types of sensor array was carried out to calculate the sensors’ impedance value, capacitance and inductance during their operation to determine the best sensor array. The contamination state was simulated by altering the electrical properties values of the environmental domain of the model to represent water contamination. Findings – The simulation results show that all types of sensor array are sensitive to conductivity, σ, and permittivity, ɛ (i.e. contaminated water). Furthermore, a set of experiments was conducted to determine the relationship between the sensor’s impedance and the water’s nitrate and su...

Assessing the Condition of Buried Pipe Using Ground-Penetrating Radar (GPR)

The invention of ground-penetrating radar (GPR) technology has facilitated the possibility of detecting buried utilities and has been used primarily in civil engineering for detecting structural defects, such as voids and cavities in road pavements, slabs and bridge decks, but has not been used to assess the condition of buried pipes. Pipe deterioration can be defined as pipes where, for example, cracking, differential deflection, missing bricks, collapses, holes, fractures and corrosion exist. Assessing the deterioration of underground pipes is important for service efficiency and asset management. This paper describes a research project that focused on the use of GPR for assessing the condition of buried pipes. The research involved the construction of a suitable GPR test facility in the laboratory to conduct controlled testing in dry sand. Plastic pipes were chosen for the experiments. A series of laboratory experiments were conducted to determine the validity and effectiveness of standard commercially available GPR technology in assessing the condition of buried utilities with common types of damage. Several types of damage to the plastic pipe were investigated with respect to different GPR antenna frequencies. The GPR surveys were carried out in order to obtain signal signatures from damaged and undamaged pipes buried at 0.5 m depth. These surveys were organised on a grid pattern across the surface of the sand in the test facility. The results presented in this paper show that GPR can identify certain types of damage associated with a buried pipe under these controlled laboratory conditions.

Exploitation selection of alpha parameter in Gravitational Search Algorithm of PID controller for computational time analysis

In this paper, a modification is done in Gravitational Search Algorithm (GSA) where an alpha parameter (α) is modified. This modification is done in order to provide different gravitational constant, G(t) and acceleration (a) to each agent as trying to improve its performance. Then this modified GSA algorithm is tested to see the effectiveness of PID controller in finding the value of KP, KI and KD of an activated sludge process (ASP) system in terms of computational time. These results are then compared with the computational time of original GSA approach and Particle Swarm Optimization (PSO) to see the effectiveness of the new approach.

Performance of Coating Materials on Planar Electromagnetic Sensing Array to Detect Water Contamination

This paper looked into the electrical properties of contaminants via planar electromagnetic sensing array (PESA), which had been coated with various types of coaters, namely, N-Methyl-2-pyrrolidone-based membrane and acrylic. Hence, the performance of the coaters had been evaluated based on the minimal difference of estimated results, which was later compared with an Agilent 85070 dielectric probe instrument. Three samples were selected for this paper, namely, nitrate, phosphate, and nickel solutions. These samples were prepared based on varied concentration levels, including 5, 25, 75, and 100 ppm. Besides, the theory for the sensor equivalent to circuit described the calculations to determine the aspects of permittivity and conductivity of the water samples. The results demonstrated that both coaters successfully estimated the electrical properties of the contaminants. The relative permittivity of all samples using the PESA coated with membrane displayed similar trends for the dielectric probe, but a slight variance was present for the PESA coated with acrylic. In fact, the relative permittivity of the nitrate sample ranged from 65 to 78 when the estimation was made using PESA coated with membrane, whereas the acrylic coater demonstrated that the relative permittivity data varied from 0.198 to 41.100. Hence, the acrylic coater failed in precision, thus inappropriate for relative permittivity estimation. Nonetheless, both coaters shared similar pattern for conductivity even with varied concentrations. However, the conductivity increased as the sample concentration increased. As such, this paper concludes that the PESA coated with membrane exhibited better performance compared with acrylic in estimating electrical properties.

Performance evaluation of vector evaluated gravitational search algorithm II

This paper presents a performance evaluation of a novel Vector Evaluated Gravitational Search Algorithm II (VEGSAII) for multi-objective optimization problems. The VEGSAII algorithm uses a number of populations of particles. In particular, a population of particles corresponds to one objective function to be minimized or maximized. Simultaneous minimization or maximization of every objective function is realized by exchanging a variable between populations. The results shows that the VEGSA is outperformed by other multi-objective optimization algorithms and further enhancements are needed before it can be employed in any application.

Synchronous gravitational search algorithm vs asynchronous gravitational search algorithm: a statistical analysis

Gravitational search algorithm (GSA) is a new member of swarm intelligence algorithms. It stems from Newtonian law of gravity and motion. The performance of synchronous GSA (S-GSA) and asynchronous GSA (A-GSA) is studied here using statistical analysis. The agents in S-GSA are updated synchronously, where the whole population is updated after each member’s performance is evaluated. On the other hand, an agent in A-GSA is updated immediately after its performance evaluation. Hence an agent in A-GSA is updated without the need to synchronize with the entire population. Asynchronous update is more attractive from the perspective of parallelization. The results show that both implementations have similar performance.