Robot gripper design is an active research area due to its wide spread applicability in automation, especially for high-precision micro-machining. This paper deals with a multiobjective optimization problem which is nonlinear, multimodal, and originally formulated. The previous work, however, had treated the actuator as a blackbox. The system model has been modified by integrating an actuator model into the robotic gripper problem. A generic actuation system (for example, a voice coil actuator) which generates force proportional to the applied voltage is considered. The actuating system is modeled as a stack consisting of the individual actuator elements arranged in series and parallel arrays in four different combinations. With the incorporation of voltage into the problem, which is related to both actuator force and manipulator displacement, the problem becomes more realistic and can be integrated with many real-life gripper simulations. Multiobjective evolutionary algorithm is used to solve the modified biobjective problem and to optimally find the dimensions of links and the joint angle of a robot gripper. A force voltage relationship can be obtained from each of the nondominated solutions which helps the user to determine the voltage to be applied depending on the application. An innovization study is further carried out to find suitable relationships between the decision variables and the objective functions.

Imparting controllable flexural rigidity into a material system is one of the key motivations for the design of intelligent materials for structural applications. In this direction, shape memory alloy (SMA) reinforced polymer composites have enormous potentials for active shape and vibration control of systems related to aerospace, automobile, and energy harvesting applications. The primary motivation of reinforcing SMA wires into a composite is to actively change the composite stiffness or elasticity through thermo-mechanical as well as electrical/magnetic stimulation. The SMA-reinforced hybrid composites are found to be able to adapt their shape, which may also improve the specific strength, vibration damping, and self-healing capability by utilizing shape memory effect and pseudoelastic behavior of the SMA. In this paper, we intend to provide a comprehensive review of all SMA-reinforced composites available today in the open literature and a critical assessment of the technology. Currently, shape memory alloys in the form of long fibers (wires), ribbons, short fibers, and particles are used for hybridizing the reinforcements in composites. Continuous SMA fiber embedded composites are generally used for shape control of structures. However, it has difficulty in obtaining suitable interfacial characteristics required for actuation. The discontinuous SMA embedded composites have scope for modifying such active properties. The work presented here gives an overview of the concepts of design, development, and modeling of continuous and discontinuous shape memory alloy embedded composites for advanced smart composites.

Mechanical metamaterials are uniquely engineered form of periodically arranged unit cells that exhibit interesting frequency-dependent physical properties like negative effective mass, Young’s modulus and Poisson’s ratio. These extreme engineering properties are beyond the natural properties of a material, which can modulate the propagation of wave. In this article, a mechanical realization of one of these uncommon properties called negative stiffness is emulated through analytical simulation. Wave propagation in metamaterials is contingent on frequency, which in turn results in transmission and attenuation bands. Simultaneous vibration control and energy harvesting can be executed by embedding energy harvesting smart material within the resonating units of the metamaterial. However, this needs careful design studies to outline the range of parameters. In this work, first, the band structure of a piezo-embedded negative stiffness metamaterial is studied using generalized Bloch’s theorem. Subsequently, harvested power along with the transmissibility is computed for a chain of finite number of metamaterial units by using backward substitution method. The results of the parametric studies elucidate that piezo-embedded negative stiffness metamaterial can enhance the performance in terms of vibration attenuation and harvested energy.