Simplifying robot hands using recursively scaled power grasps

Author(s):  
Lael U. Odhner ◽  
Chad Walker ◽  
Aaron M. Dollar
Keyword(s):  
2021 ◽  
Vol 15 (2) ◽  
pp. 139-139
Author(s):  
Naoki Asakawa

Due to changes in the global industrial structure, the number of employees in the manufacturing industry has decreased in developed countries. One of solutions to this situation offered in Industry 4.0 is “the utilization of robots and AI as alternatives to skilled workers.” This solution has been applied to various operations conventionally performed by skilled workers and has yielded consistent results. A skilled worker has two skills, namely, “physical operation skill” and “decision making skill,” which correspond to the utilization of robots and AI, respectively. Conventionally, robots have simply played back programs they were taught. However, owing to feedback technologies using force, position, or various other sensors, robots have come to be able to perform smart operations. In some of these, the capabilities of robots exceed those of human workers. For example, while humans are highly adaptive to various operations, it is difficult for them to maintain a constant force or position for long periods of time. Generally, humans make decisions about operations according to their experience, and this experience is gained from many instances of trial and error. Now, the trial-and-error learning of AI has become significantly superior to that of humans in terms of both number and speed. As a result, many systems can find operational strategies or answers much faster than humans can. This special issue features papers on robot hands, path planning, kinematics, and AI. Papers related to robot hands present an actuator using new principles, new movements, and the realization of the precise sense of the human hand. Papers related to path planning present path generation on the basis of CAD data, path generation using image processing, automatic path generation on the basis of environmental information, and the prediction of error and correction. Path generation using VR technology and error compensation using an AI technique are also presented. A paper related to kinematics presents the analysis and evaluation of a new mechanism with the aim of new applications in the field of machining. In closing, I would like to thank the authors, reviewers, and editors, without whose hard work and earnest cooperation this issue could not have been completed and presented.


2009 ◽  
Vol 419-420 ◽  
pp. 645-648 ◽  
Author(s):  
Qun Ming Li ◽  
Dan Gao ◽  
Hua Deng

Different from dexterous robotic hands, the gripper of heavy forging manipulator is an underconstrained mechanism whose tongs are free in a small wiggling range. However, for both a dexterous robotic hand and a heavy gripper, the force closure condition: the force and the torque equilibrium, must be satisfied without exception to maintain the grasping/gripping stability. This paper presents a gripping model for the heavy forging gripper with equivalent friction points, which is similar to a grasp model of multifingered robot hands including four contact points. A gripping force optimization method is proposed for the calculation of contact forces between gripper tongs and forged object. The comparison between the calculation results and the experimental results demonstrates the effectiveness of the proposed calculation method.


Author(s):  
L. Lu ◽  
C. Cai ◽  
A. H. Soni

Abstract For an arbitrarily shaped object manipulated by a robot hand, this paper presents a procedure for analyzing the position and rotation ranges of the object, and a procedure for designing the kinematic parameters of a hand to meet given requirements on the motion ranges. Rotation dexterity index, dexterity charts, and a dexterity scalar characterizing both position range and rotation range are introduced for the performance evaluation of a robot hand. Least-square-error iteration and steps are detailed for the kinematic parameter determination of a robot hand.


Author(s):  
Xiaochun Gao ◽  
Shin-Min Song

Abstract Unlike in wheeled vehicles, compliance in walking machine systems changes due to the variation of leg geometry, as its body proceeds. This variation in compliance will cause vibration, even if external loads remain constant. A theory is thus developed to predict the body vibrations of a walking machine during walking. On the other hand, dynamic foot forces under body vibrations can be computed by application of the existing numerical methods. As an example, the body vibrations of a quadrupedal walking chair under different walking conditions are simulated in terms of the developed theory. The results show that the influence of body vibrations on the foot force distribution is essential and, in some cases, the walking chair may lose its stability due to its body vibrations, even though it is identified to be stable in a quasi-static analysis. The developed theory can also be extended to other similar multi-limbed robotic systems, such as multi-fingered robot hands.


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