Mohammad Keshmiri

Augmented Image-Based Visual Servoing of a Manipulator Using Acceleration Command

This paper presents a new image-based visual servoing (IBVS) controller named augmented IBVS for a 6-DOF manipulator. The main idea of this controller is that it produces acceleration as the controlling command. A proportional-derivative controller is developed to provide the robot with the controlling command. This controller can achieve a smoother and more linear feature trajectory in the image space and decrease the risk that the features leave the field of view. The developed control method also enhances the camera trajectory in 3-D space. The stability of the proposed method is fully investigated by using the Lyapunov method and the perturbed systems theory. Experimental tests are performed on a 6-DOF robotic system to validate the effectiveness of the proposed controller. The performance of the controller is compared with that of a conventional IBVS.

Performance comparison of various navigation guidance methods in interception of a moving object by a serial manipulator considering its kinematic and dynamic limits

In this paper a comparative analysis is represented on various navigation guidance methods used for intercepting fast maneuvering moving objects. A glancing revision is introduced on relevant works within the introduction section. Four common methods for navigation guidance known as PNG, APNG, IPNG and AIPNG are under investigation. Results demonstrate their infirmity on smoothly intercepting a moving object. Hence, to improve the navigation guidance methods and to adapt them with robotic problems a modified version of AIPNG is proposed for 2D problems and is developed for 3D problems utilization.

Augmented Imaged Based Visual Servoing controller for a 6 DOF manipulator using acceleration command

This paper presents a new imaged based visual servoing controller called Augmented Imaged Based Visual Servoing (AIBVS) for a 6DOF manipulator. A proportional derivative (PD) controller is developed considering acceleration as the controlling command of the robot. This controller can achieve smooth and linear feature trajectory in image space and decrease the risk of features leaving the field of view. The developed control method also enhances the camera trajectory in 3D space. The stability of proposed method is fully investigated by using Lyapunov method and the perturbed systems theory. Being an IBVS method, this method also shows the robustness with respect to some camera calibration errors. Simulation results on a 6 DOF robotic systems validate the effectiveness of the proposed controller.

Augmented online point to point trajectory planning, a new approach in catching a moving object by a manipulator

In a structured dynamic environment, due to the known variation of the environment, robot trajectory planning can be performed robots motion starts. Within an unstructured dynamic environment, environment variations are permanent, so that the surroundings information must be acquired in an online action. Likewise the data acquisition, robot trajectory planning must be executed online. In this paper a method for online trajectory planning based on adaptive prediction planning and execution (APPE) is proposed for robotic manipulators considering velocity and torque constraints. A vision-based data acquisition system is used to acquire object positions and velocities. To describe the end-effector trajectories in joint and Cartesian space a set of time polynomial function are used. Initially a primary trajectory is planned and it will be updated in definite time periods. This action will be frequently repeated until catching is occurred. Proposed method has been tested on an experimental setup and the experimental results are presented.

Design, simulation and manufacturing of a Tracked Surveillance unmanned ground vehicle

This paper describes design, Simulation and manufacturing procedures of HIRAD - a teleoperated Tracked Surveillance UGV for military, Rescue and other civilian missions in various hazardous environments. A Double Stabilizer Flipper mechanism mounted on front pulleys enables the Robot to have good performance in travelling over uneven terrains and climbing stairs. Using this Stabilizer flipper mechanism reduces energy consumption while climbing the stairs or crossing over obstacles. The locomotion system mechanical design is also described in detail. The CAD geometry 3D-model has been produced by CATIA software. To analyze the system mobility, a virtual model was developed with ADAMS Software. This simulation included different mobility maneuvers such as stair climbing, gap crossing and travelling over steep slopes. The simulations enabled us to define motor torque requirements. We performed many experiments with manufactured prototype under various terrain conditions Such as stair climbing, gap crossing and slope elevation. In experiments, HIRAD shows good overcoming ability for the tested terrain conditions.

Catching moving objects using a Navigation Guidance technique in a robotic Visual Servoing system

In this paper, a combination of Navigation Guidance algorithm with an Augmented Imaged Based Visual Servoing (AIBVS) strategy is proposed to perform a moving object catching with fast manoeuvrability. An eye-in-hand vision system is utilized with a 6DOF robotic manipulator. Navigation guidance algorithms are usually exploited in moving object interceptions specially for military purposes such as following and colliding with missile and aircraft. In this paper, we have modified and applied these methods to a robotic system to catch a moving object with different motions. An imaged based catching controller is proposed using a modified navigation guidance algorithm in a robotic visual servoing system. The simulation results are presented for catching a moving object with three different motions of constant velocity, sinusoidal and a thrown object.

An observer-based state feedback controller design for robot manipulators considering actuators' dynamic

In this paper a state feedback controller is designed for Rigid Link Electrically-Driven (RLED) manipulators actuated by a brushed DC (BDC) motors based on joint velocity estimation. The observer based controller is in fact a model based controller but it can be shown practically that the method is robust against parametric uncertainties. Initially pseudo-velocity filter is proposed to estimate the joints velocity, provided joints position are measured. Using the measured and estimated states, a controller is designed through the direct Lyapunov method. It is shown that the controller is asymptotically stable in its region of attraction, both in position and velocity tracking. To show the validity of the proposed scheme, the algorithm is implemented on a two link planar manipulator actuated by BDC motors.

Dynamic Analysis and Control Synthesis of Undesired Slippage of End-Effectors in a Cooperative Grasping

Abstract This paper addresses dynamic analysis and control synthesis of object grasping in a cooperative multirobot system with n-serial manipulators from an undesired slippage point of view. Two control approaches are presented in this article; a modified version of a conventional method in grasp synthesis and a new method based on a new modeling of system dynamics. A new formulation for frictional contact is used in dynamical modeling, where equality and inequality equations of the standard Coulomb friction model are all converted to a single second-order differential equation. A multiphase controller is utilized to control the object trajectory tracking as well as object slippage in the new control approach. Performance and robustness of both approaches are studied numerically. The results show superiority of the new method and its desirable and excellent performance.

A Comparative Study of Eye-In-Hand Image-Based Visual Servoing: Stereo vs. Mono

Visual control of manipulators provides significant advantages when working with targets with unknown positions. Among all visual servoing categories, the stereo visual servoing has shown to be very effective when dealing with unstructured environments. In this paper a comparative study of eye-in-hand image-based visual servoing (IBVS) for two approaches of stereo and mono vision is presented and various cases of control schemes, and tracking and prediction algorithms are studied. In this study the vision systems are considered to be mounted on the end-effector of a 6 degrees of freedom (DOF) manipulator robot. Additionally, a method for position prediction and trajectory estimation of the moving target in order to use in a real-time catching task is proposed and developed using Kalman Filter and Extended Kalman Filter (EKF) as the trajectory estimators. Using the proposed estimation methods, the quality of the visual servoing in a catching procedure using a 6-DOF manipulator robot is compared for mono and stereo visual servoing systems. Finally, by applying the newly introduced acceleration command-based controller (AIBVS) to the visual servoing system, the results for both cases are presented to compare the effects on the quality of servoing tasks. The aforementioned scenarios of visual servoing are simulated and implemented based on a 6-DOF DENSO 6242G robot.

Adaptive manipulation and slippage control of an object in a multi-robot cooperative system

Considering undesired slippage between manipulated object and finger tips of a multi-robot system, adaptive control synthesis of the object grasping and manipulation is addressed in this paper. Although many studies can be found in the literature dealing with grasp analysis and grasp synthesis, most assume no slippage between the finger tips and the object. Slippage can occur for many reasons such as disturbances, uncertainties in parameters, and dynamics of the system. In this paper, system dynamics is analyzed using a new presentation of friction and slippage dynamics. Then an adaptive control law is proposed for trajectory tracking and slippage control of the object as well as compensation for parameter uncertainties of the system, such as mass properties and coefficients of friction. Stability of the proposed adaptive controller is studied analytically and the performance of the system is studied numerically.