Theoretical studies suggest and experimental evidence confirms that maintaining changing human joint stiffness by coactivated antagonistic muscles are metabolically expensive, even if do not perform net mechanical work. Based on this observation, we posit effective augmentation can be achieved actuators operated in parallel to joints, these only supplement without doing In article, present a prototype variable-length leaf-spring actuator capable of large-range modulation. The key feature the...

Compliant actuators are typically designed to possess a tunable positive stiffness characteristic in order generate restoring force upon displacement. These either require two independent motor units or closed-loop control change both their equilibrium position and output stiffness. The introduction of negative stiffness, combination with may reduce the complexity extend capability these unexpected ways. In this paper, we present compliant actuator that employs passive mechanism conjunction...

Designing robotic systems capable of low-power operation, inherent to their compliant actuation, has been elusive in practical application. In this paper, we propose a physical measure mathematically define mechanical designs that are suitable realize stiffness modulation with low power cost. Using measure, present mathematical formulation an ideal variable mechanism unaffected by the external load during its operation. We then analyze several existing mechanisms from literature relate...

Size reduction is a constant objective in new technologies for which very accurate devices are needed when manipulating submillimetric objects. A kind of microfabricated microrobot based on the use bistable modules designed to perform open-loop controlled micropositioning tasks. The DiMiBot (a specific digital microrobot) opens paradigm design microrobots by using mechanical stability instead complex control strategies. We propose architecture forward and inverse kinematics models easy use....

This article deals with the optimization of main element a digital microrobot, which is bistable module. module consists curved beams and electrothermal actuators. A design study beam actuator presented in order to achieve limits line miniaturization. Finally, An for dimensions proposed respect microfabrication elastic limits.

Compliant actuators enabling low-power stiffness adaptation are missing ingredients and key enablers of next generation robotic systems. One the components these is mechanism implementing that requires sophisticated control nontrivial mechanical design. However, despite recent advances in controlling systems, their design remains experience based not well understood. In this paper, we present an optimization-based computational framework for intrinsically compliant variable mechanisms. The...

Piezoelectric actuators are widespread in the design of micro/nanorobotic tools and microsystems. Studies toward integration such complex micromechatronic systems require size reduction these while retaining a wide range performance. Two main fabrication processes currently used for piezoelectric actuators, providing very different behaviors: (i) use bulk lead zirconate titanate (PZT) layer (ii) thin film growth. In this paper, we propose trade-off between two extreme technologies order to...

This paper introduces an analytical approach for the design of variable stiffness mechanisms. The basis this is a general model - representing potential energy function and physical constraints covering space Using model, we present systematic procedure to analytically define classes mechanisms from first principles. Consequently, identify capable infinite range modulation using bounded motor forces, simplest mathematical in class. A prototype mechanism consistent with canonical designed,...

High precision manipulation becomes a recurrent need in micro or nanoscale. Microrobots based on active material were designed to perform micromanipulation tasks various environments such as microrobotic stations electronic microscopes (SEM, TEM). These materials are used generate proportional actuation, but show some drawbacks we want avoid (non linearity, integration of sensors, ...). In this paper propose new type microrobot, called digital microrobot. It is the use bistable modules (Fig....

Microrobotics is an ongoing study all over the world for which design often inspired from macroscale robots. We have proposed of a new kind microfabricated microrobot based on use binary actuators in order to generate highly accurate and repeatable tool positioning tasks at microscale without any sensor (with open-loop control). Our previous work consisted design, modeling, fabrication, characterization first planar digital microrobot. In this paper, we focus motion planning robot...