Analyzing dexterous hands using a parallel robots framework

Borràs, Júlia Beltrán; Dollar, Aaron M.

doi:10.1007/s10514-013-9380-x

Cited by 25 publications

(8 citation statements)

References 31 publications

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“…There are several approaches to define the matrix that maps the joint velocities _ q to the platform/object 6-dimensional twist v (Tsai, 1999). Here we will use the theory of reciprocal screws using the framework presented in Borràs and Dollar (2014), that is based on a parallel robot framework (Mohamed and Duffy, 1985). The matrix J is called the Jacobian matrix of the system, and defines the linear relationship between the object twist and the velocities at the joints as…”

Section: Fully Actuated Hand Static Equilibrium Equationsmentioning

confidence: 99%

“…where m is the coefficient of friction and is taken as 0.7 for the executions. Note that the formulation introduced so far is general and can be applied to any hand following results in Borràs and Dollar (2014).…”

Section: Fully Actuated Hand Static Equilibrium Equationsmentioning

confidence: 99%

“…They studied how to design fingers to avoid singularities and applied a numerical approach to define its optimal dimensions. In contrast, we will analyze the hand-plus-object and its properties as a whole using a mathematical framework from parallel manipulators adapted to robotic hands (Borràs and Dollar, 2013b, 2013a, 2014, using screw theory similarly as done in works such as Cui and Dai (2012). The parallelism between parallel robots and grasping has been used before to define dexterity measures for grasping (Bicchi and Prattichizzo, 2000).…”

Section: Introductionmentioning

confidence: 99%

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Dimensional synthesis of three-fingered robot hands for maximal precision manipulation workspace

Borràs

Dollar

2015

The International Journal of Robotics Research

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This paper applies dimensional synthesis to explore the geometric design of dexterous three-fingered robotic hands for maximizing precision manipulation workspace, in which the hand stably moves an object with respect to the palm of the hand, with contacts only on the fingertips. We focus primarily on the tripod grasp, which is the most commonly used grasp for precision manipulation. We systematically explore the space of design parameters, with two main objectives: maximize the workspace of a fully actuated hand and explore how under-actuation modifies it. We use a mathematical framework that models the hand-plus-object system and examine how the workspace varies with changes in nine hand and object parameters such as link length and finger arrangement on the palm. Results show that to achieve the largest workspaces the palm radius should be approximately half of a finger length larger than the target object radius, that the distal link of the two-link fingers should be around 1-1.2 times the length of the proximal link, and that fingers should be arranged symmetrically about the palm with object contacts also symmetric. Furthermore, a proper parameter design for an under-actuated hand can achieve up to 50% of the workspace of a fully actuated hand. When compared to the system parameters of existing popular hand designs, larger palms and longer distal links are needed to maximize the manipulation workspace of the studied design.

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Section: Fully Actuated Hand Static Equilibrium Equationsmentioning

confidence: 99%

Section: Fully Actuated Hand Static Equilibrium Equationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dimensional synthesis of three-fingered robot hands for maximal precision manipulation workspace

Borràs

Dollar

2015

The International Journal of Robotics Research

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“…Some researchers began to focus on parallel manipulators because of the advantages they hold over their serial counterparts: high stiffness, high accuracy, quick response speed, and high payload to weight ratio. A large number of new architectures dealing with the kinematics and dynamics of parallel manipulators have been proposed in academic [1,2], while some of them have been implemented to practical applications, e.g., parallel kinematic machine [3], motion simulator platform [4], surgical medical equipment [5], dexterous hands [6], etc. However, in order to achieve potential advantages over serial manipulators, parallel manipulators still require improvement in the design, modeling, analysis, and optimization, while the development of control schemes also provides a field for improving the performance of the parallel manipulators to some extent [7].…”

Section: Introductionmentioning

confidence: 99%

Adaptive Fuzzy Sliding Mode Control for a 3-DOF Parallel Manipulator with Parameters Uncertainties

et al. 2020

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Parallel manipulators possess the advantages of being compact structure, high stiffness, stability and high accuracy, so such parallel manipulators have been widely employed in application fields as diverse as parallel kinematic machine, motion simulator platform, medical rehabilitation device, and so on. Due to the complexity of the closed-loop structural system, an accurate dynamic model is very difficult to be derived in the absence of some uncertainties parameters and external disturbances. In order to improve the trajectory tracking accuracy with time-varying and nonlinear parameters, this paper addresses the design and implement of adaptive fuzzy sliding mode control (AFSMC) for a three-degree-of-freedom (DOF) parallel manipulator, where internal force term can be linearly separated into a regression matrix and a parameter vector that contains the estimated errors. Furthermore, fuzzy inference unit is utilized to modify the gain parameters in real-time by using the state feedback from the task space and the adaptive law is performed to update uncertainties in dynamic parameters. The proposed controller is deduced in the sense of Lyapunov theory to guarantee the stability while improving the trajectory tracking performance. Finally, simulation experiment results demonstrate that the proposed control method is insensitive to uncertainties and disturbances and permits to decrease the requirement for the bound of these uncertainties, which validate the effectiveness of the developed control method and exhibit good trajectory tracking performance compared with sliding mode control (SMC) and fuzzy sliding model control (FSMC).

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“…Based on the concept of a parallel mechanism, Özgür et al [10,11] designed a dexterous hand and obtained a new type of grasping mechanism. Borràs et al [12,13] also designed a dexterous hand by using the parallel mechanism concept and analyzed the dexterous hand through the force-closure method. The kinematics problem of the dexterous hand is solved by analyzing a Jacobian matrix of the formed parallel mechanism.…”

Section: Introductionmentioning

confidence: 99%

Design of Self-Reconfigurable Multiarm Robot Mechanism Based on Deployable Kinematic Chains

Zhao

Guo

et al. 2020

Chin. J. Mech. Eng.

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As the structures of multiarm robots are serially arranged, the packaging and transportation of these robots are often inconvenient. The ability of these robots to operate objects must also be improved. Addressing this issue, this paper presents a type of multiarm robot that can be adequately folded into a designed area. The robot can achieve different operation modes by combining different arms and objects. First, deployable kinematic chains (DKCs) are designed, which can be folded into a designated area and be used as an arm structure in the multiarm robot mechanism. The strategy of a platform for storing DKCs is proposed. Based on the restrictions in the storage area and the characteristics of parallel mechanisms, a class of DKCs, called base assembly library, is obtained. Subsequently, an assembly method for the synthesis of the multiarm robot mechanism is proposed, which can be formed by the connection of a multiarm robot mechanism with an operation object based on a parallel mechanism structure. The formed parallel mechanism can achieve a reconfigurable characteristic when different DKCs connect to the operation object. Using this method, two types of multiarm robot mechanisms with four DKCs that can switch operation modes to perform different tasks through autonomous combination and release operation is proposed. The obtained mechanisms have observable advantages when compared with the traditional mechanisms, including optimizing the occupied volume during transportation and using parallel mechanism theory to analyze the switching of operation modes.

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Analyzing dexterous hands using a parallel robots framework

Cited by 25 publications

References 31 publications

Dimensional synthesis of three-fingered robot hands for maximal precision manipulation workspace

Dimensional synthesis of three-fingered robot hands for maximal precision manipulation workspace

Adaptive Fuzzy Sliding Mode Control for a 3-DOF Parallel Manipulator with Parameters Uncertainties

Design of Self-Reconfigurable Multiarm Robot Mechanism Based on Deployable Kinematic Chains

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