This work presents a study of the frictional effect on the stability of a three-rigid link object manipulated by two cooperative robot arms in a plane. It is supposed that the three-rigid link object interacts with the two robot arms at multi contact points to perform the nonprehensile manipulation of the object. The object is figured out in a way such that one of the arms is in contact with two links of the object, while the other arm is free to slide along the third link. The effect of changing frictional forces at the contact points as well as their directions on the stability of the manipulated object is to be explored by defining the system constraints. A definition of what is called the “Stability Margin” is obtained. For the same orientation of the object links, the Stability Margin is a region of equilibrium contact points between the sliding arm and the corresponding object link where the robot arm could be placed in without dropping the object. Later, an experimental system consisting of a three-rigid link object and a two planar robot arms manipulation system is equipped to verify the concept.

This paper deals with the design process and the dynamic control simulation of a new type of 4-DOFs parallel mechanism that can be used as an endoscopic surgical manipulator. The proposed mechanism, 2-PUU_2-PUS, is designed based on the parallel virtual chain concept and screw theory. Based on the structure analysis of the 4-DOF parallel mechanism, the inverse position equation is studied using the inverse analysis theory of kinematics. The design and the stress analysis of the mechanism are investigated using SolidWorks software. The virtual prototype of the parallel mechanism is constructed, and the dynamic simulation is performed using ADAMS™ software. The system model utilizing PID and PI controllers has been built using MATLAB software. A more realistic simulation in accordance with a given bending angle and point to point control is implemented by the use of both ADAMS/MATLAB softwares. The simulation results showed that this control method has solved the coordinate control for the 4-DOF parallel manipulator so that each output is feedback to the four driving rods. From the results, the tracking performance is achieved. Other control techniques, such as intelligent ones, are recommended to improve the tracking performance and reduce the numerical truncation error.

This paper presents the design of two controllers namely, Direct Fuzzy Logic controller and Fuzzy Model Reference Learning Control applied to a new aerial manipulation system called "Quad rotor-Manipulator System". This system consists of 2-link manipulator connected to the bottom of a quad rotor. The dynamic model of this system is derived taking into account the effect of adding a payload to the manipulator. The performance of the proposed controllers are compared with that of the previously developed controller based on Feedback Linearization technique. All controllers are tested regarding their ability to stabilize the system and track desired trajectories under the effects of picking and placing a payload as well as changing the system operating region. Finally, the system equations of motion and the control laws are simulated using MATLAB/SIMULINK. The simulation results indicate the outstanding performance of the Fuzzy Model Reference Learning Control.

This paper describes the development of a dexterous endoscopic parallel manipulator for laparoscopic surgery using rigid mechanism. Endoscopic parallel manipulator is developed based on the concept of virtual chain and screw theory. The inverse and forward kinematics solutions are derived analytically and numerically respectively. Also the singularity analysis is investigated. The known problem of limited bending angles was solved in the proposed manipulator as it can reach ± 90° in any direction. The proposed manipulator consists of four legs; two legs are 2-PUU (each leg consists of one active prismatic joint and two passive hook joints); the other two legs are 2-PUS (each leg consists of one active prismatic join, one passive hook joint and one passive spherical joint). The virtual prototype of the parallel mechanism was constructed in ADAMS. The kinematics simulation of the virtual prototype was realized. Four linear motors are used to drive the mechanism. The intuitive simulations with the combination of MATLAB/Simulink and ADAMS show that the control performance of kinematics analysis is satisfactory.