Norsinnira Zainul Azlan

Fuzzy Logic Controlled Miniature LEGO Robot for Undergraduate Training System

Fuzzy logic enables designers to control complex systems more effectively than traditional approaches as it provides a simple way to arrive at a definite conclusion upon ambiguous, imprecise or noisy information. In this paper, we describe the development of two miniature LEGO robots, which are the line following and the light searching mobile robots to provide a better understanding of fuzzy logic control theory and real life application for an undergraduate training system. This study is divided into two parts. In the first part, an object sorter robot is built to perform pick and place task to load different colour objects on a fuzzy logic controlled line following robot which then carries the preloaded objects to a goal by following a white line. In the second part, an intelligent fuzzy logic controlled light searching robot with the capability to navigate in a maze is developed. All of the robots are constructed by using the LEGO Mindstorms kit. Interactive C programming language is used to program fuzzy logic robots. Experimental results show that the robots has successfully track the predefined path and navigate towards light source under the influence of the fuzzy logic controller; and therefore can be used as a training system in undergraduate fuzzy logic class.

Proportional Integral Sliding Mode Control of Hydraulic Robot Manipulators with Chattering Elimination

This paper is concerned with the application of a robust control approach based on sliding mode control (SMC) strategy with proportional integral switching surface in controlling the position trajectory of a hydraulic manipulator. This paper also addresses the suppression technique for the undesirable chattering phenomenon which usually occurs in SMC by replacing the discontinuous controller sign function with a proper continuous function. Chattering is unwanted because it leads to an excessive usage and damages the actuators and therefore the control law may become impractical. In this study, an integrated model of hydraulically actuated robot that considers both the manipulator linkage and actuator dynamics is used to provide a more suitable model for controller synthesis and analysis. The control technique is stable in the large based on Lyapunov theory. Its performance is evaluated and compared with the existing independent joint linear control (IJC) technique through computer simulation. The results prove that the controller has successfully force the robot manipulator to track the desired position trajectory for all times and has better performance than IJC

Modeling and Proportional Integral Sliding Mode Control of Hydraulic Manipulators

This paper is concerned with the mathematical modeling and the application of a new position tracking control technique for hydraulic manipulators. The integrated model takes into account both the manipulator linkage as well as the actuator dynamics to represent a closer dynamic behaviour of the real system, thus providing a more suitable model for the purpose of advanced controller synthesis and analysis. Although hydraulic manipulators provide large torque and fast response, they possess highly nonlinear dynamics, parameter variations, uncertain load disturbances and strong couplings among various joints. Therefore, a robust control approach based on proportional integral sliding mode control (PISMC) technique is adopted to provide position tracking for the system. It will be shown that the proposed controller is practically stable and is successful in forcing the robotic system to track the predefined desired trajectory at all time. A 3 DOF revolute robot manipulator is used in this study.

KANE's method for dynamic modeling

Kanes method is becoming increasingly popular among the dynamists because of its advantages over the Newton-Euler and Lagrange. Many of the literatures have used Kanes method successfully to model the dynamic systems but none has provided a detailed and quick explanation on how to implement the method on a system. This paper provides a fast and easy guide to learn the Kanes method, especially for the beginners. A dynamic model of 3 DOF kinematic chain has been developed as an example to demonstrate the detailed steps involved in modeling using Kanes method. The formulated model is then verified successfully using Lagrange method.

Adaptive Control of Robotic Arm Carrying Uncertain Time-Varying Payload Based on Function Approximation Technique

This paper presents a new adaptive controller based on the Function Approximation Technique (FAT) for a 2 degree of freedom (DOF) robot arm carrying uncertain time-varying payload. The mathematical model of the arm is expressed as the summation of the known and the uncertain terms in deriving the proposed control law. The time-varying uncertainty is expressed using an FAT expression, which avoids the need of linear parameterization of the mathematical model of the robotic arm. The expression also allows the update law to be easily derived by an appropriate choice of Lyapunov-like function. The stability proof of the controller is described in detail and computer simulation results are presented to demonstrate the effectiveness of the proposed technique.

Prototype Modeling of Security System with Metal Detector

The security system provides the ease to people in order to manage their mall easier and this system is concern on the security of each item. This system will provide not only the items identification but also the anti-theft security. Nowadays, each items produced have a barcode that is printed on its surface as product code. The old system seems not to fully utilize the barcode on each item. This system combines the barcode with electromagnetic security strips in order to reduce the security cost. The barcode strip will be developed in two layers, the barcode and the magnetic strip. The system is working such as the customers self service in the library. The items need to be check at the counter before it been taking out from the store. If the item is not registered then, the alarm will give a warning when it passes through the electromagnetic gate. The LabVIEW program developed by National Instrument is found out to be the best selection as the wave recognition to this system. Identification of patrons and materials by barcode is a reliable technique and gave great service when combined with electro-magnetic security device.

Feedback Error Learning control for underactuated acrobat robot with Radial Basis Function based FIR filter

This paper presents a new Feedback Error Learning (FEL) scheme with the application of Radial Basis Function Network (RBFN) based Finite Impulse Response (FIR) filter to control underactuated systems. This method provides a stable feedback controller which is systematically derived from sequential backstepping control procedure. Besides, it also formulates a simple approach for FEL feedforward controller structure by employing the inverse dynamic model of the plant with physical parameters. The RBFN based FIR filter is used in obtaining the estimation of the state variables to produce an ideal feedforward control input. Simulation results on a two link acrobat robot with nonzero initial angular momentum in achieving a final desired posture angle are presented to show the validity of the proposed algorithm.

Human Hand Motion Analysis during Different Eating Activities

The focus of this research is to analyse both human hand motion and force, during eating, with respect to differing food characteristics and cutlery (including a fork and a spoon). A glove consisting of bend and force sensors has been used to capture the motion and contact force exerted by fingers during different eating activities. The Pearson correlation coefficient has been used to show that a significant linear relationship exists between the bending motion of the fingers and the forces exerted during eating. Analysis of variance (ANOVA) and independent samples t-tests are performed to establish whether the motion and force exerted by the fingers while eating is influenced by the different food characteristics and cutlery. The middle finger motion showed the least positive correlation with index fingertip and thumb-tip force, irrespective of the food characteristics and cutlery used. The ANOVA and t-test results revealed that bending motion of the index finger and thumb varies with respect to differing food characteristics and the type of cutlery used (fork/spoon), whereas the bending motion of the middle finger remains unaffected. Additionally, the contact forces exerted by the thumb tip and index fingertip remain unaffected with respect to differing food types and cutlery used.

Human lower arm analysis during different eating activities

Human lower arm motion analysis is essential in developing robotic rehabilitation systems for assisting people during eating activities. In this research, human wrist and elbow joints motion is analyzed during five different eating activities and using different cutleries which are the fork and spoon. Xsens Motion Tracker (MTw™) has been used to capture the orientation data in the form of Euler angles of the wrist and elbow joints while eating various food types. The orientation data trajectories of the wrist and elbow joints have been analyzed and important events identified while eating several food types. Statistical tests like analysis of variance (ANOVA) and t-test have been performed to investigate if the motion of the wrist and elbow is influenced by the type of food and the cutlery used. The ANOVA and t-test results revealed that the motion of the wrist and elbow varies according to various food types and as well as the cutlery used during eating. The wrist joint movements showed more significant variations than the elbow joint while eating various food types and using different cutleries that is, the spoon and fork.

Control of cooperative manipulators in holding deformable objects

This paper presents the implementation of a control system to control cooperative manipulators to hold deformable objects. The aim is to hold the deformable object without having information on the shape and stiffness of the deformable object beforehand. The prototype of a pair of manipulators has been designed and built to test the controller. A force sensor and a rotary encoder are used to give feedback to the controller, which controls the DC motor actuators accordingly. A position proportional-integral-derivative (PID) controller technique has been applied for one of the manipulators and a PID force control technique is applied to the other. Simulations and experimental tests have been conducted on models and the controller has been implemented on the real plant. Both simulation and test results prove that the implemented control technique has successfully provided the desired position and force to hold the deformable object with maximum experimental errors of 0.34mm and 50mN respectively.