Although the dimensional synthesis of dexterous hands with traditional rigid palms has been carried out, research on the dimensional synthesis of dexterous hands with metamorphic palms remains insufficient. The system performance under the proposed control can be guaranteed by the theoretical proofs and demonstrated by the simulation of a three-fingered hand robot in the three-dimensional work space.Ĭurrent research on robotic dexterous hands mainly focuses on designing new finger and palm structures, as well as developing smarter control algorithms. With the formulated contact forces model, a model-based dynamic control method is proposed for the hand robot to handle the object, which does not depend on the force feedback from the fingertips sensors (force sensorless).

In virtue of following the servo constraints, the hand robot can manipulate the object to accomplish the desired task. Motivated by Udwadia’s work, the manipulation task of the grasped object is novelly used to formulate a set of servo constraints. Consider the hand robot and the object as an entire system in the control design. Through the second order of the contact constraints, the grasping forces of the hand robot in the manipulation work space are derived explicitly and decoupled with the control torques of the finger joints. Based on the contact constraints, the explicit dynamics modeling of the hand robot manipulating an object is hierarchically established by Udwadia–Kalaba equation with no auxiliary variable (e.g., Lagrange multipliers or quasi-generalized variables). The kinematics of the fingers are presented to investigate the workspace performance, and the statics are analyzed to prove that the proposed parallel dexterous hands can provide desirable pinching force.Ī novel analytical modeling and dynamic manipulation control method of the multi-fingered hand robot has been proposed in the paper. The hands have high task adaptability that can perform the pinching operations both from the outside and inside the cavity of the objects. The in-hand configurations are actually hybrid mechanisms, whose motion properties are analyzed by equivalent to the parallel mechanisms (PMs). Two three-finger dexterous hands are designed by assembling the obtained parallel fingers on the palm in the same direction.

The finger structures of RR-RPR and 2-UU-UPU are presented by structural evolution from the well-known PMs of parallelogram and 3-UU by means of group deduction, respectively. Based on the motion property of human finger, the required motion types of the dexterous hands are proposed. This paper focuses on designing dexterous hands based on the parallel finger structures to improve above performances. The dexterous hands with high dexterity, high carrying capability, high precision and high task adaptability (multipurpose) are demanded in industry.

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