Ahmed Abo-Ismail

Modeling and control of a new quadrotor manipulation system

This paper introduces a new quadrotor manipulation system that consists of a 2-link manipulator attached to the bottom of a quadrotor. This new system presents a solution for the drawbacks found in the current quadrotor manipulation system which uses a gripper fixed to a quadrotor. Unlike the current system, the proposed system enables the end-effector to achieve any arbitrary orientation and thus increases its degrees of freedom from 4 to 6. Also, it provides enough distance between the quadrotor and the object to be manipulated. This is useful in some applications such as demining applications. System kinematics and dynamics are derived which are highly nonlinear. Controller is designed based on feedback linearization to track desired trajectories. Controlling the movements in the horizontal directions is simplified by utilizing the derived nonholonmic constraints. Finally, the proposed system is simulated using MATLAB/SIMULINK program. The simulation results show the effectiveness of the proposed controller.

Methodology for identifying quadrotor parameters, attitude estimation and control

This paper describes a methodology to identify all the parameters of a quadrotor system including the structure parameters and rotor assembly parameters. A CAD model is developed using SOLIDWORKS to calculate the mass moment of inertia and all the missing geometrical parameters. A three simple test rigs are built and used to identify the relationship between the motor input Pulse Width Modulation (PWM) signal and the angular velocity, the thrust force, and drag moment of the rotors. A simple algorithm is implemented to an inertial measurement unit (IMU) for estimating the attitude and altitude of the quadrotor. Experimental set up is built to verify and test the accuracy of these proposed techniques. A controller is designed based on the feedback linearization method such that the quadrotor attitude can be stabilized. Finally, the experimental results show the effectiveness of the proposed techniques and the controller design.

Development of parallel manipulator sit to stand assistive device for elderly people

This paper describes a novel mobility assistive device under development in the Egypt-Japan University of Science and Technology (E-JUST). The proposed system can help patients who do not have enough physical strength on the lower limbs during sit to stand due to aging, diseases such as polymyositis and myopathy, and joint replacement surgery complications. It can follow the natural pattern of human motion during sit to stand providing assistance force under the shoulder. The overall device is compact and employees a parallel mechanism which provide more stiffness. Several experiments were carried out in a VICON room to calculate the human motion posture while sit to stand motion in addition estimate the trajectory of the end effector during assisting. Computer simulation was built to verify the performance of the proposed system with the reference trajectory.

Modeling and static analysis of a three-rigid-link object for nonprehensile manipulation planning

This work presents the dynamic modeling and the static analysis of a three rigid link object manipulated by two cooperative arms in a plane. Such analysis is required as a step prior to the nonprehensile manipulation planning of the object. The system is configured in a way such that one of the two robot arms is in contact with two links of the object, while the other arm is in contact with the third link. The purpose of the static analysis is to obtain the interaction forces as well as their locations between the object links and the arms required to hold the object for a specified configuration. The dynamic model of the system is introduced, and the static analysis considering both the frictionless and frictional contact cases between the arms and the object links is deduced. The effect of changing the direction of the static frictional forces at multi contact points is introduced.

Development of an assistive device for elderly people: Fuzzy sensor fusion experimental study

This paper describes a prototype of an assistive device for elderly people under development at the Egypt-Japan University of Science and Technology (E-JUST) named E-JUST Assistive Device (EJAD). Several experiments were carried out using VICON system and inertial sensors to determine the human posture while sit to stand motion. EJAD uses two inertial sensors fused through an ANFIS algorithm. EJAD imitates the real motion of the caregiver. It consists of two main parts, a robot arm and an active walker. The robot arm is a 2-DOF planner manipulator. In addition, a back support with a passive joint will support the patients back. Inertial sensors are used to compensate and adapt EJAD system depending on obtaining the patient posture through the measurements of the inertial sensors on the leg and trunk of the patient. ANFIS algorithm is applied to convert the inertial sensors signals to the right posture of the patient. A control scheme is proposed to control the system based on practical measurements taken from experiments. Computer simulation shows a good performance of EJAD in helping the patient.

ANFIS based Jacobian for a parallel manipulator mobility assistive device

Nowadays parallel manipulators are used widely in bioengineering applications; this leads to many exciting expectations as well as challenges. The kinematic analysis of parallel manipulators with their differential kinematics yielding the Jacobian in a closed form is not a trivial task. In this paper a parallel manipulator based mobility assistive device called EJADII is analyzed to determine forward kinematics, inverse kinematics and closed-form Jacobian. An Adaptive Neuro-Fuzzy Inference System (ANFIS) is trained to estimate the Jacobian. This system would be useful when determination of the Jacobian in a closed-form is difficult to determine. The human motion during sit to stand captured by VICON experiment is used with two assisting scenarios to train and verify this system. Computer simulations show relatively good results of the proposed system.

Skid steering mobile robot modeling and control

In this paper, a reduced order model of dynamic and drive models augmentation of a skid steering mobile robot is presented. Moreover, a Linear Quadratic Regulator (LQR) controller augmented with a feed-forward part is designed for controlling this reduced order model. The controller is simple in terms of design and implementation in comparison with complex nonlinear control schemes that are usually designed for this system. Moreover, it provides good performance for the plant comparable with a nonlinear controller based on the inverse dynamics which depends on the availability of an accurate model describing the system. Simulation results are included.

Fuzzy-based gain scheduling of Exact FeedForward Linearization control and sliding mode control for magnetic ball levitation system: A comparative study

This paper presents a comparative study between two control approaches; an Exact FeedForward Linearization controller developed by fuzzy-gain scheduling and sliding mode controller based on Ackermann and Utkin method. For the later one the sliding surface dynamics are determined explicitly without transforming to the sliding mode canonical form. The benefits of this study are demonstrated practically on a well known benchmark control problem, Magnetic ball levitation system (Maglev), and the performances of both controllers are compared. Important control issues such as tracking ability, control effort, steady state error and noise rejection are experimentally investigated.

Sit to stand sensing using wearable IMUs based on adaptive Neuro Fuzzy and Kalman Filter

This paper present a method for measuring the posture of a human body during different phases of sit to stand motion using inertial sensors. The proposed method fuses data from inertial sensors placed in trunk and thigh using Adaptive Neuro-Fuzzy Inference System (ANFIS) followed by a Kalman Filter (KF). The ANFIS attempts to estimate the position of shoulder of the human, at each sampling instant when measurement update step is carried out. The Kalman filter supervises the performance of the ANFIS with the aim of reducing the mismatch between the estimated and actual. The performance of the method is verified by measurements from VICON (motion analysis system). The obtained results show the effectiveness of the proposed algorithm in prediction the human shoulder position with root mean square error 0.018 m and 0.016 m in the x and y direction, respectively.

Workspace mapping and control of a teleoperated endoscopic surgical robot

This paper presents the experimental implementation of a teleoperated endoscopic surgical manipulator system that uses PHANTOM Omni haptic device as the master. The 4-DOF, 2-PUU 2-PUS, endoscopic surgical parallel manipulator design is carried out using screw theory and Parallel virtual chain methodology to have larger bending angles and workspace volume. The master and slave devices of the teleoperation system are dissimilar in their kinematics and workspace volumes. A workspace mapping technique is implemented based on Position with Modied Rate Control to navigate through the slave workspace without annoying the user. To control the motion of the slave robot, a PID controller is used. The experimental results show the feasibility of the teleoperation surgical system using the 4-DOF parallel manipulator. Also, they indicate the efficiency of the implemented mapping technique and the designed controller to span the slave workspace with high dexterity and good tracking which allows the surgeon to perform the operation with high accuracy.