Ruhizan Liza Ahmad Shauri

An analytical process of 2D sonar sensor low altitude field mapping for UAV application

Analytical processes is performed for calculating point distance using ultrasonic sensors, with the intention to resolve a low-altitude two-dimensional surface mapping using UAV. An experimental structure model was constructed to allow for dynamic one-dimensional movement of the sensor system in a horizontal plane. Sample experimental surfaces are chosen to be scanned by the sensor system and recreation of the two-dimensional profile was implemented using a 16-bit microcontroller unit. The recreated profiles are shown for comparison between the calculated and actual values, which proved to be nearly similar.

PID position control for 2-DOF robotic finger

This paper presents the evaluation of motor performance for different loads, PID tuning and evaluation of the new PID values for a two degree of freedom (DOF) robotic finger. The prototype 2-DOF finger which has been developed in a separate study has two joints and two links, and is made of prospective plastic material. The control system comprises of two DC-micromotors, magnetic encoders, a motion controller unit and a PC. Initially, an experiment to observe the effect of different loads to the motor is implemented. The observation is then used for the PID controller tuning to improve the position control performance in terms of the overshoot, rise time, peak time, settling time and the error. Next, the evaluation of the position control with the new PID parameters is implemented to the robotic finger for continuous motions of the motor at three different positions. Motion manager software provided by the Faulhaber Company is used to obtain the encoder measurement for the motor position and to execute command to run the motor. From the experimental data, it can be observed that with the new controller parameters the performance of motor has shown improvement for both robot joints. This proves that the efficiency of motor control is an important element for developing robotic finger for performing task at high precision standard.

PID position control of 7-DOF three-fingered robotic hand for grasping task

This paper presents the tuning of PID control parameters for position feedback control of motor and the position reference design for grasping task by a 7-degree of freedom (DOF) three-fingered robotic hand. The system of the robotic hand consists of DC-motors, magnetic encoder and a motion controller unit. The robotic hand has three fingers where each finger has two joints and two links made of perspective plastic material. The PID tuning is implemented to all six motors that are used to move all joints of the three fingers. Trial and error method is used for tuning the parameter of PID control to improve the transient response performance of the motors. For the position reference design, a set of position data is identified to produce the grasping trajectory for all finger joints. The trajectory for the robotic hand performs two types of finger configuration for grasping two different shapes of household solid objects. Both works were implemented via programming in Motion Manager Application. It has been observed that the robot hand has performed well with the tuned PID parameters by reducing the overshoot, rise time (Tr), peak time (Tp), settling time (Ts) and steady state error (ess). Besides, the robot hand has also succeeded the grasping task with the proposed position reference trajectory.

Real-time vision based sensor implementation on unmanned aerial vehicle for features detection technique of low altitude mapping

Feature detection is an important task for an autonomous vehicle in getting reference or guide in a agriculture field. Recently, a lot of sensors were implemented for feature detection of a field such as sonar sensor, laser range finder, infrared sensor which it is used as height estimation, size area measurement and path tracking that act as reference for desired measurement in creating a virtual map of the agriculture field which can be used as autonomous vehicle navigation process. A vision based sensor is implemented on the unmanned area vehicle for low altitude mapping. Real-time process with minimum computational process and light weight devices is required and utilized as it used UAV as the transportation element. An experimental setup utilized an analog camera as the front end sensor for the desired detection. The experimental surface is scanned by the analog vision sensor for sensor accuracy analysis used for feature detection application. The process technique is implemented via the medium speed 16-bit processor microcontroller which avoids the requirement of high-speed processor to do image processing. The vision sensor will be utilized into an unmanned aerial vehicle used for feature detection scheme for field measurement. The composing image produced is shown for comparison with the actual image as for performance analysis of the vision based sensor. The designed technique gave acceptable error of image accuracy that adequate to use for features detection on unmanned aeria vehicle.

Dynamic Height Measurement using Sonar Sensor Based on Single Dimension Kalman Filter in Embedded Controller

The aim of this paper is to evaluate real-time accurateness of low-altitude height measurement using a single sonar sensor via Kalman filter algorithm in embedded controller. The function of the one dimension embedded Kalman filter of sonar sensor is to reduce and resolve the error of low altitude height measurement that produced from the sensor for mapping application. Series data of varied height measurement with Kalman filter was gathered and implemented using a 16-bit micro controller unit. A structure model was constructed to allow for dynamic height measurement between ground surface and the sensor. The tabulated data are shown for comparison of accuracy and error analysis between both with Kalman and without Kalman filter. After several scanned surfaces and analysis of the recorded data, the technique shows the usefulness in height measurement application that used surface scan method which the sonar project to the ground such as UAV in order to reduce error of the detected varied height.

Development of 7-DOF three-fingered robotic hand for industrial work

The purpose of this project is to design and construct a seven degree of freedom (DOF) three-fingered robotic hand. This project is the continuity from a previous work which has successfully constructed two-DOF robotic finger. In this work, a palm that holds all the three fingers is designed and the design of the current finger is improved. All components are fabricated and assembled to produce a complete robotic hand. SolidWorks software is used to design the palm and finger which considers the selection of motor, spur gears, and appropriate shape of palm. The range of motion is visualized to confirm the design with the desired application. Then, the motion of the proposed hand design is validated based on a control study which is carried out in separate work using Motion Manager Application. It can be observed from the experimental results that the robotic hand is capable of moving according to the proposed mechanism and the desired positions before successfully grasped two types of household objects with all its three fingers. This also proved that the proposed designs worked well for the task assigned by user. Thus, the resulted robotic hand can be potentially applied as the end effectors of an industrial robot for product manipulation in near future.

Robot Hand Fingertip Design Validation

Among the challenges in designing robot hand is to make it feature packed but still maintaining a compact human-hand sized without compromising its robustness. The previous work had elaborated the design process of a three-fingered robot hand until a functioning prototype is successfully produced. However, the performance of the robot hand for grasping was insufficient. This paper will discuss the enhancement in the existing design to incorporate force sensing ability with better grip-ability of the fingertip. The improved design fingertip was fabricated using rapid prototyping machine. Then, two miniature load cells were fitted into the fingertip to enable force sensing in two directions namely x-axis and z-axis. The fingertip maintains the easy-to-replace feature, improving the tip surface for better grasping and creating canal-shaped gap to have a compliant-like material effect when the fingertip is subjected to any external force. From the calibration result, it can be observed that the measured force is linearly related to the applied force in both x and z axes to prove the feasibility of the proposed design.

Calibration of embedded force sensor for robotic hand manipulation

This paper discusses the calibration of two-axis force sensors which were embedded into the fingertip of a three-fingered robot hand. In a previous work, a functioning prototype of the three-fingered robot hand has been successfully developed. However, the performance of the robot hand for grasping was insufficient. Therefore, the improved design fingertip was developed to enhance the existing design by incorporating force sensing ability for better grasping task. Two miniature load cells button were fitted into the fingertip to enable force sensing in two individual directions namely x-axis and z-axis. The calibration is implemented in both axes. The calibration results proved that the linearity calibration is relevant to be used as the reference force for force control development in the next phase.

PID position control of three-fingered hand for different grasping styles

This paper describes the design of reference position and the application of PID (Proportional Integral Derivative) position control for a three-fingered robot hand. The robot hand consists of six DOF robot fingers and one DOF palm that have been designed and fabricated in a previous work. The reference position for the control system is designed on Matlab Simulink based on two grasping styles as instructed by the user. This is the initial stage of preparing the three-fingered robot hand for grasping objects of different shapes. PID control is applied for the position control of motors programmed on Matlab Simulink and encoders are used to provide the feedback measurement of the motor positions in real time. The interface developed between PC Matlab Simulink programs, Arduino controller, motor drivers and sensors is also presented. The experimental result shows that the designed reference position has been successfully worked to provide the grasping styles and the PID control has sufficiently control the robot fingers for the desired task in real time.

On-board real-time single line scanning technique for used on unmanned aerial vehicle of low altitude mapping

Create a map is an initial task for a robot to maneuver or navigated automatically in a proposed area. It is a difficult task for a robot creates a map and performs the desired task concurrently especially on an aerial application. Aerial application needs a simple and light computational method in order to process the applied algorithm. This paper presents a distinctive technique of single line scanning technique via vision based sensor. The vision algorithm is processed consequently on the embedded controller board that is attached on the UAV. The simple morphological algorithm is designed which consist of thresholding, binarization and recognition of the image captured. The structured platform is moving while the proposed technique is processed and it scanned the features underneath the platform. The processed images are used for features identification and feature size measurement. The processed images and the future UAV data are wirelessly monitored via the wireless transceiver devices. The result proves that the method proposed is applicable for features detection application that would be utilized on the UAV. Also it is proved that the proposed method is totally on-board real time process and gave sufficient accuracy for the future detection recognition application.