Energy-Efficient Robot Configuration and Motion Planning Using Genetic Algorithm and Particle Swarm Optimization

The implementation of Industry 5.0 necessitates a decrease in the energy consumption of industrial robots. This research investigates energy optimization for optimal motion planning for a dual-arm industrial robot. The objective function for the energy minimization problem is stated based on the execution time and total energy consumption of the robot arm configurations in its workspace for pick-and-place operation. Firstly, the PID controller is being used to achieve the optimal parameters. The parameters of PID are then fine-tuned using metaheuristic algorithms such as Genetic Algorithms and Particle Swarm Optimization methods to create a more precise robot motion trajectory, resulting in an energy-efficient robot configuration. The results for different robot configurations were compared with both motion planning algorithms, which shows better compatibility in terms of both execution time and energy efficiency. The feasibility of the algorithms is demonstrated by conducting experiments on a dual-arm robot, named as duAro. In terms of energy efficiency, the results show that dual-arm motions can save more energy than single-arm motions for an industrial robot. Furthermore, combining the robot configuration problem with metaheuristic approaches saves energy consumption and robot execution time when compared to motion planning with PID controllers alone

Hydrogels toughened by biominerals providing energy-dissipative sacrificial bonds

Inspired by bone tissues, we mineralized low crystalline hydroxyapatite (HAp) particles in double network (DN) hydrogels, and we observed that the HAp minerals toughen the gels. The contribution of dissipated energy from HAp minerals was over 500% higher than that from the polymer during tensile deformation. We elucidated that the amorphous parts in the HAp minerals break at deformation, acting as energy-dissipative sacrificial bonds. This result implies that not only brittle polymer networks but also minerals can provide sacrificial bonds to toughen soft materials

Effect of Relative Strength of Two Networks on the Internal Fracture Process of Double Network Hydrogels As Revealed by in Situ Small-Angle X-ray Scattering

Double network hydrogels (DN gels) exhibit extraordinarily high strength and toughness by interplay of the two contrasting networks: the rigid, brittle network serves as a sacrificial bond that fractures at a relatively low strain, while the soft, stretchable network serves as hidden length that sustains stress by large extension afterward. The internal fracture process of the brittle network strongly depends on the relative strength of the two networks. In this study, we study the internal fracturing process of typical DN gels that show yielding or necking under uniaxial stretching using in situ small-angle X-ray scattering. Two samples consisting of the same brittle first network from poly(2-acrylamido-2-methylpropanesulfonic acid) but stretchable second network from poly(N,N-dimethylacrylamide) of different concentrations were adopted. We found that (1) the brittle network shows nonaffine deformation even far below the yield strain by local fracture; (2) for the sample of low second network concentration, significant strain amplification occurs around the submicrometer-scale voids (defects) preexisting in the brittle network, which induces the fracture percolation of brittle network from voids to show the necking phenomenon; and (3) the strain amplification at voids is suppressed in the sample of high second network concentration, and fracture of brittle network occurs dispersedly, showing yielding without necking

Anisotropic Growth of Hydroxyapatite in Stretched Double Network Hydrogel

Bone tissues possess excellent mechanical properties such as compatibility between strength and flexibility and load bearing owing to the hybridization of organic/inorganic matters with anisotropic structure. To synthetically mimic such an anisotropic structure of natural organic/inorganic hybrid materials, we carried out hydroxyapatite (HAp) mineralization in stretched tough double network (DN) hydrogels. Anisotropic mineralization of HAp took place in stretched hydrogels, as revealed by high brightness synchrotron X-ray scattering and transmission electron microscopic observation. The <i>c</i>-axis of mineralized HAp aligned along the stretching direction, and the orientation degree <i>S</i> calculated from scattering profiles increased with increasing in the elongation ratio λ of the DN gel, and <i>S</i> at λ = 4 became comparable to that of rabbit tibial bones. The morphology of HAp polycrystal gradually changed from spherical to unidirectional rod-like shape with increased elongation ratio. A possible mechanism for the anisotropic mineralization is proposed, which would be one of the keys to develop mechanically anisotropic organic/inorganic hybrid materials