Latest Papers

ASME Journal of Mechanisms and Robotics

  • Double-Layer Deployable Mechanical Network Constructed of Threefold-Symmetric Bricard Linkages and Sarrus Linkages
    by Song X, Guo H, Chen J, et al. on June 4, 2021 at 12:00 am

    AbstractThreefold-symmetric (TFS) Bricard linkages are known for their excellent deployment performance properties. This paper proposes a novel networking method of TFS Bricard linkages and a double-layer mechanical network. First, the angle relationship for parts of the TFS Bricard linkage is analyzed. Then, the angle relationship of two TFS Bricard linkages connected by a scissor mechanism is studied. The result suggests that when the twist angles of the two TFS Bricard linkages are equal, their corresponding planes are parallel, and the link lengths have no effect on the parallel relationship. A novel networking method of the TFS Bricard linkage is recommended according to these results. This mechanical network is constructed of two different sized units and can be plane deployed and be folded with a smaller height. We also propose a hybrid linkage constructed of the TFS Bricard linkage and Sarrus linkage. Two kinds of double-layer mechanical networks are suggested by applying the hybrid linkage to a smaller unit in the mechanical network and using the hybrid linkage as the interlayer pillar. The new networking method and the double-layer mechanical network provide convenience for the TFS Bricard linkage's engineering application.

  • Design of Robotic Motion Platform Utilizing Continuous Contact Skating
    by Kumar R, Gupta V, Agarwal S, et al. on June 4, 2021 at 12:00 am

    AbstractThe continuous contact-based skating technique utilizes the sideway movement of the two skates while changing the orientation of the two skates simultaneously. The skates remain in contact with the surface. A mathematical model mimicking a continuous skating technique is developed to analyze the kinematic behavior of the platform. Kinematic and dynamic equations of motion are derived for the nonholonomic constraints. Heuristic-based motion primitives are defined to steer the robotic platform. For the lateral movement of the platform, a creeping-based motion primitive is proposed. A prototype of the robotic platform is developed with three actuated degrees-of-freedom—orientation of two skates and distance between them. A multibody model of the platform is also developed in matlab. Analytical expressions are verified using simulation and experiments. The robotic platform follows the desired motion profiles. The motion profiles include straight-line motion, motion in a circular curve, and lateral creep-like motion of the platform. However, the initial deviation has been observed in both the simulations and experiments due to the slipping of the roller skate at the contact point with the surface. The platform can be effectively used in a structured environment.

  • Direct Kinematic Analysis of the Spatial Parallel Mechanism With 3-R(P)S Structure Based on the Point Pair Relationship
    by Zhu G, Wei S, Zhang Y, et al. on June 4, 2021 at 12:00 am

    AbstractThis paper demonstrates a novel geometric modeling and computational method of the family of spatial parallel mechanisms (PMs) with 3-R(P)S structure for direct kinematic analysis based on the point pair relationship. The point pair relationship, which is derived from the framework of conformal geometric algebra (CGA), consists of the relationship between the point and the point pair and two point pairs. The first research is on the distance relationship between the point and the point pair. Second, the derivation of the distance relationship between two point pairs is based on the aforementioned result, which shows the mathematical homogeneity. Third, two formulations for a point of the point pairs that satisfy the distance relationship between two point pairs are reduced. Fourth, the point pair relationship is applied to solve the direct kinematic analysis of the spatial parallel mechanism with 3-R(P)S structure. Finally, four numerical examples are provided to verify the validity of the proposed algorithm. Overall, the proposed method can be generalized for the direct kinematics of a series of spatial parallel mechanisms with 3-R(P)S structure.

An Affordable Linkage-and-Tendon Hybrid-Driven Anthropomorphic Robotic Hand—MCR-Hand II

Abstract

This paper presents the design, analysis, and development of an anthropomorphic robotic hand coined MCR-hand II. This hand takes the advantages of both the tendon-driven and linkage-driven systems, leading to a compact mechanical structure that aims to imitate the mobility of a human hand. Based on the investigation of the human hand anatomical structure and the related existing robotic hands, mechanical design of the MCR-hand II is presented. Then, using D-H convention, kinematics of this hand is formulated and illustrated with numerical simulations. Furthermore, fingertip force is deduced and analyzed, and mechatronic system integration and control strategy are addressed. Subsequently, a prototype of the proposed robotic hand is developed, integrated with low-level control system, and following which empirical study is carried out, which demonstrates that the proposed hand is capable of implementing the grasp and manipulation of most of the objects used in daily life. In addition, the three widely used tools, i.e., the Kapandji score test, Cutkosky taxonomy, and Kamakura taxonomy, are used to evaluate the performance of the hand, which evidences that the MCR-hand II possesses high dexterity and excellent grasping capability; object manipulation performance is also demonstrated. This paper hence presents the design and development of a type of novel tendon–linkage-integrated anthropomorphic robotic hand, laying broader background for the development of low-cost robotic hands for both industrial and prosthetic use.
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