Abstract This paper proposes a method for optimizing rectilinear tasks on a 3 degree of freedom (DoF) modular serial metamorphic manipulator. The overall experimental process was designed in order for theoretical assumptions and previous experimental results, regarding the characteristics of a class of reconfigurable manipulators to be verified. The optimization procedure undergoes two stages. In each stage, the tasks are initially simulated and the optimal solutions obtained are afterwards evaluated in the manipulator. Optimal task placement in the configuration space of the reference anatomy is concerned in the first optimization stage. Two different kinematic manipulability measures are utilized to form the objective function of the genetic algorithm (GA) used. Determination of the optimal anatomy for each task execution is concerned in the second stage. All feasible anatomies are exhaustively evaluated and the anatomy with minimum execution time achieved in simulation is considered as optimal. The simulated tasks are executed for the reference and the optimal anatomy extracted. Overall task execution time reduction is measured. For tasks executed, Tool Center Point (TCP) position and velocity are obtained from navigation equations using measurements from an Inertial Measurement Unit (IMU) sensor. In order to obtain more accurate solutions from position and velocity equations, a Kalman Filter (KF) algorithm is implemented. Finally, conclusions are made based on the results of each task execution. Overall the metamorphic manipulator can achieve higher kinematic performance and minimize task execution time for the optimal anatomy calculated. Optimal task placement for the reference anatomy also reduces the task execution time.

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In this paper, the inertia characteristics of a 2 Degrees of Freedom (DoF) serial metamorphic manipulator (SMM) structure are investigated. Link mass redistribution is utilized as the dynamic decoupling design approach. The metamorphic structure of the manipulator provides the ability to perform mass redistribution, through the altering of the pseudojoints configuration(anatomy metamorphosis). The overall number of design parameters is reduced and simplicity of the proposed methodology is enhanced. The procedure presented, is executed for a 2 DoF SMM and the advantages of the metamorphic structure, compared with fixed anatomy manipulators, are featured.

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The inherit complexity of the determination of the optimal anatomy and structure to task requirements and specification for metamorphic manipulators poses a significant challenge to the end user, as such methods and tools to undertake such processes are required for the implementation of metamorphic robots to real-life applications in various fields. In this work, the methodology for an offline process for the determination of the optimal anatomy maximizing performance under different requirements is presented. Such requirements considered in this work include the kinematic, kinetostatic and dynamic performance of the manipulator during task execution. The proposed methodology is then applied to a 3 D.o.F. metamorphic manipulator for different tasks. The presented results clearly show that a single metamorphic structure is able to provide the end user with different anatomies, each better suited to task specifications.