The Researchers seeking to expand the capabilities of robots have begun looking to biological systems for inspiration. One particularly agile creature, the gecko lizard, is remarkably adept at maneuvering across both flat and vertical surfaces. The study of the gecko’ s adhesive system has informed the design of several synthetic adhesives in recent years. These low consuming energy adhesives had a successful performance in climbing robots and robotic grippers. The existing grippers mainly use tendon mechanism for transmitting force inside the gripper and electrical motors for actuating the gripper. This paper concentrates on design and fabrication of a new gripper which uses solenoid for actuation, and Scuttt-Russel mechanism instead of tendon mechanism for transmitting force. The new gripper is more robust and cheaper than existing grippers. To verify the applicability of proposed gripper, experiments were conducted on a variety of substrates that demonstrated the gripper’ s successful operation. Experimental results demonstrated 4. 6, 4. 5 and 4. 1 kPa average normal adhesion pressure on the surface of acrylic, steel and glass respectively. Also, maximum measured adhesion increased 20% in comparison with previous tendon gripper. The results illustrate that a Solenoid actuator with Scott-Russel mechanism has the potential to be used as a new actuator in geckoinspired gripper.

Grasping in robot gripper is an operation that is inevitably performed by prosthetic hands or industrial robots. Meanwhile, slipping of the grasped object is considered as an undesirable phenomenon in any kind of grasping. Here, the computed torque control is used in order to control slip and also guarantee the desired behavior of the closed loop system. Nevertheless, any acceleration changes of the robot’s joints before completing the response time of the slip controller has a direct effect on the object position relative to the robot and causes slip phenomenon. Although the applied computed torque controller is suitable for tracking trajectory, the desired trajectory will be altered according to slip occurrence. This paper introduces a method to modify the desired trajectory during grasping an object. The modification is done according to the measured slip. These methods not only control the slip of the grasped object, but also compensate it. So the object could be handled and placed in its proper position in the task space. This approach guarantees the safe grasping and moving of objects according to object position relative to the gripper.

In this paper, a new kind of gripper is designed which passively conforms to the shape of an object. This universal gripper is proposed when some of the adaptability of a human hand is needed or situations where very different objects need to be gripped easily, reliably within rapid succession without any feedback. By adding an annular balloon around the granular bag, a lateral force pushes the main membrane and increases the friction force between the bag and the load. According to the acquired test results reported in this paper, the modification on this new robotic gripping mechanism is effective and the the successful gripping is formulated. This new complete formulation can provide a good estimation for a successful gripper design.

In this paper, a new multi-objective differential evolution with a diversity preserving mechanism called the ε-elimination algorithms is used for the Pareto optimum design of gripper mechanisms. The ε-elimination diversity is used to improve the population diversity among the obtained Pareto front. In the ε-elimination diversity approach based on a threshold value all the clones or ε- similar individuals are recognized and simply removed from the current population. It should be noted that such e-similarity must exist both in the space of objectives and in the space of the associated design variables. The proposed algorithm has been used for two different configuration of robot’s gripper. The dimensions of mechanisms are considered as design variables and optimally selected by proposed algorithm to improve the efficiency of gripper mechanism. Two conflicting objectives which are the difference between maximum and minimum gripping forces and the transmission ratio of actuated and experienced gripper forces, are considered for Pareto optimization. The best configuration of gripper mechanism is suggested by comparing of trade-off design points. The comparisons of the obtained Pareto front using the method of this paper with those obtained in other references shows a significant improvement.

This paper deals with the problem of safe grasping of an object. According to robot maneuvers during movement, the slipping or falling of the objects is possible. Here, an adaptive back stepping control method is used for controlling of slipping and tracking of desirable paths. First, the robot dynamics of grasping of an object including mechanical arm with three rotational joints, one prismatic joint, jaw gripper as well as dynamic of the electrical actuators is derived. Then, back stepping technique, which is a systematic approach based on Lyaponov theory, is applied for this nonlinear system. Because of existence of different uncertainties in this system such as mass and inertia of robot and object mass, it is required to design a controller to be able to cope with these uncertainties. Accordingly, a stable controller using adaptive back stepping control methodology is also designed to estimate of these parameters’ uncertainties. Stability analysis is provided based on Lyapunov theory. Simulations are carried out to evaluate the performance of the proposed controller. Results show the effectiveness of the proposed control method.

Grasping in unstructured environments is one of the most challenging issues currently facing robotics. The inherent uncertainty about the properties of the target object and its surroundings compels the use of robot hands, which typically involve complex hands, require elaborate sensor suites, and are difficult to control. For this purpose, in this paper combining the kinematic structure of a three and two links finger for design and fabrication of robotic gripper will be evaluated. First, the challenges associated with grasping by careful mechanical design of gripper are analyzed. Then, the design and fabrication of a sample gripper by combining a three-links finger similar to the human index finger and a two-links finger similar to the thumb are described. In the following, the performance of this hand for grasping various objects will be examined. The results show that with two fingers and simple design, without the need for the complex control, c various objects can be grasped successfully. Also, the results demonstrate that compared with the previous researches and by proximity to the kinematic structure of the human hand fingers, by combining two with three link fingers this gripper will have a better performance than the previous symmetric gripper for successfully grasping large objects.

The purpose of this study is to experimentally evaluate the performance of two models of new type of contact pneumatic grippers. One of them is two-dimensional and the other one is axisymmetric, which uses a dual throat ejector to handle limp and porous materials. In two-dimensional device, slotted plates with different slot width were used to investigate the effect of slot width and total pressure of inlet flow on the performance of the gripper. In the axisymmetric gripper, perforated rings with different hole diameters were used to evaluate their effect and the effect of high-pressure inlet flow on the performance of the device. Results show that in both grippers, by increasing inlet pressure, the induced pressure and suction force to hold limp materials increases. Also, regardless of the gripper mass flow rate consumption, the axisymmetric gripper with higher mass flow consumption creates more force and suction pressure, but the performance of the two-dimensional gripper in producing suction force is much better by considering the mass flow rate consumption.