Ahmad Zaki Shukor

3-D Biped Robot Walking along Slope with Dual Length Linear Inverted Pendulum Method (DLLIPM)

A new design method to obtain walking parameters for a three-dimensional (3D) biped walking along a slope is proposed in this paper. Most research is focused on the walking directions when climbing up or down a slope only. This paper investigates a strategy to realize biped walking along a slope. In conventional methods, the centre of mass (CoM) is moved up or down during walking in this situation. This is because the height of the pendulum is kept at the same length on the left and right legs. Thus, extra effort is required in order to bring the CoM up to higher ground. In the proposed method, a different height of pendulum is applied on the left and right legs, which is called a dual length linear inverted pendulum method (DLLIPM). When a different height of pendulum is applied, it is quite difficult to obtain symmetrical and smooth pendulum motions. Furthermore, synchronization between sagittal and lateral planes is not confirmed. Therefore, DLLIPM with a Newton Raphson algorithm is proposed to solve these problems. The walking pattern for both planes is designed systematically and synchronization between them is ensured. As a result, the maximum force fluctuation is reduced with the proposed method.

Horizontal Distance Identification Algorithm for Sit to Stand Joint Angle Determination for Various Chair Height Using NAO Robot

This paper presents the development of an autonomous Sit To Stand (STS) motion using NAO robot. NAO robot hip limitation will emulate the limitation faced by people having STS problem. To perform the motion, three main steps have been developed (1) horizontal distance identification, (2) joint angle determination, and (3) stability control. This step was developed based on Alexander STS technique. Results show that NAO robot is able to achieve halfway stand up from chair height between 9.6 and 12.7 cm automatically. The robot’s best performance is at 12.7 cm height with swinging time of 0.52 s in experiment and 0.2914 in simulation. The developed system will contribute to the development of exoskeleton, rehabilitation and evolution of humanoid robot. This system also enhances NAO’s ability for medical study on STS motion or as tools in searching for the best chair design.

Design and Development of a Closed Room Monitoring System

This paper discusses a method for implementing a closed room monitoring system. It forms the basics of a home/building security system. The research focuses on the controller design, the devices used and visual interface seen from the Personal Computer (PC). In addition, the system incorporates a data-logging feature of the sensors used. This is useful, because it involves memory card storage. Even if the system is off-line from the PC, the state of the sensors can still be monitored via memory card.

An automated remote messaging system using GSM communications

This paper discusses a method for implementing Global System for Mobile communications (GSM) control of a Light Emitting Diode (LED) Messaging Display for advertising purposes. The existing LED display will be used and integrated with the custom-built GSM controller board, inclusive of microcontroller for control and data transmission to the GSM modem

The Effect of Parameters Variation on Bilateral Controller

Efficiency, reliability, high power quality and continuous operation are important aspects in electric vehicle attraction system. Therefore, quick fault detection, isolation and enhanced fault-tolerant control for open-switches faults in inverter driving systems become more and more required in this filed. However, fault detection and localization algorithms have been known to have many performance limitations due to speed variations such as wrong decision making of fault occurrence. Those weaknesses are investigated and solved in this paper using currents magnitudes fault indices, current direct component fault indices and a decision system. A simulation model and experimental setup are utilized to validate the proposed concept. Many simulation and experimental results are carried out to show the effectiveness of the proposed fault detection approach.The inverter with critical loads should be able to provide critical loads with a stable and seamless voltage during control mode change as well as clearing time. The indirect current control has been proposed for providing stable voltage with critical load during clearing time and seamless control mode transfer of inverters. However, the islanding detection is difficult since with the indirect current control the magnitude and frequency of voltage do not change when the islanding occurs. The conventional anti-islanding method based on the magnitude and frequency of voltage variation cannot apply to the indirect current control. This paper proposes an islanding detection method for the indirect current control. The proposed islanding detection method can detect the islanding using reactive power perturbation and observation when the frequency and magnitude of voltage don’t vary during clearing time. In order to verify the proposed anti-islanding method, the experimental results of a 600W three-phase inverter are provided.

A review of haptic communication technology based on bilateral teleoperation system

This paper explores the role of haptics in wireless communication and bilateral system to improve the development on bilateral teleoperation system in the future. The telecommunication applications in haptic is to separate between master and slave control in various distances. This purpose is commonly used in medical surgery between different countries or buildings. This technology helps to analyse medical disease and remote human life. In addition, this paper first reviews about Wi-Fi offloading technique comparison between cellular network and Wi-Fi network to achieve ideal connectivity within long range distance. Mobile Node (MN) are the main factor in wireless communication to obtain minimum time delay are also been reviewed in this paper. Apart with telecommunication studies, there are several parameter need to be control comparatively noise ratio, signal strength and signal power was put forward in this paper. Secondly, the implementation of Disturbance Observer between master and slave control and receive the tactile feedback in various fields. DOB control the closed loop system consists of main feedback on the effects of dynamic uncertainties and external disturbances into a single disturbance term in the teleoperation system.

Investigating the relation between standing period and stability of humanoid robot when performing STS motion

The main challenge in STS is addressing the lift-off from chair problem. In solving the problem, two method was proposed, 1) phase and trajectory planning based on the Alexander STS technique and 2) motion control which applied IF-THEN rules to control the action given (direction and gain) with aid of proportional velocity control. This paper discussed on the trajectory planning to perform STS motion by, 1) Observation of the relationship between standing velocity i.e standing period, Ts with the stability of the STS motion and 2) Introduce a limitation on bodys angular direction in y-axis on saggital plane, angle y. Nao humanoid robot is used to perform the task. Angle y trajectory and centre of pressure, CoP reading was measured to validate the proposed method. The results show that Standing period, Ts plays important role in order to perform a stable STS motion where stability increased as Ts increased. The lowest RMSE is 8.83° when Ts = 3.0. When the forward momentum decreasing with the implementation of angle y trajectory limitation, the results shows RMSE increased as Ts increased. However, the lowest RMSE is 7.07° when Ts = 1.5 where RMSE was decreased while using much lower standing period, Ts. The proposed angle y limitation has improved the motion stability and able to perform the task faster.

Musculoskeletal Robotics Modeling and Simulation

This paper presents the kinematics and dynamics of a musculoskeletal model inspired by humans/animals where the bones (links) are actuated by muscles (linear actuators). Starting from a single-link musculoskeletal structure, the kinematics were addressed to link the joint and muscle variables. From the kinematic constraints, dynamics of the structure were also presented. Later the 3D model of a two-link structure was constructed in ROCOS software to simulate the effect of gravity and environment (floor). In the simulations, the constraints were correctly defined as snapshots show the bones and muscle are intact before and after contact with environment.