The paper focuses on the stiffness modeling of robotic manipulators with gravity compensators. The main attention is paid to the development of the stiffness model of a spring-based compensator located between sequential links of a serial structure. The derived model allows us to describe the compensator as an equivalent non-linear virtual spring integrated in the corresponding actuated joint. ...

We study some spring mass models for a structure having a unilateral spring of small rigidity ε. We obtain and justify an asymptotic expansion with the method of strained coordinates with new tools to handle such defects, including a non negligible cumulative effect over a long time: Tε ∼ ε−1 as usual; or, for a new critical case, we can only expect: Tε ∼ ε−1/2. We check numerically these resul...

In automotive dry clutch systems the cushion spring plays an important role in terms of gradually torque transmitted during the engagement phase. In fact, it strongly influences the clutch torque transmission from engine to driveline through its non-linear loaddeflection curve. Therefore, to improve the gearshift performance in automated manual transmission is fundamental the knowledge of the c...

We have analyzed the response of bead-spring chain models in strong elongational flow as the amount of polymer represented by a spring s changed. We examined the longest relaxation time of the chains which is used to quantify the strength of the flow in terms of a Weissenberg umber. A chain with linear springs can be used to predict the longest relaxation time of the nonlinear chains if the lin...

Over the years, several approaches have been devised to widen the operating bandwidth, but most of them can only be triggered at high accelerations. In this work, we investigate a broadband energy harvester based on combination of non-linear stiffening effect and multimodal energy harvesting to obtain high bandwidth over wide range of accelerations (0.1 g-2.0 g). In order to achieve broadband b...