let $s$ be a monoid. in this paper, we prove every class of $s$-acts having a flatness property is closed underdirected colimits, it extends some known results. furthermore thisresult implies that every $s$-act has a flatness cover if and only if it has a flatness precover.

For many tasks, predictive path-following control can significantly improve the performance and robustness of autonomous robots over traditional trajectory tracking control. It does this by prioritizing closeness to the path over timed progress along the path and by looking ahead to account for changes in the path. We propose a novel predictive pathfollowing approach that couples feedforward li...

The time required to image large samples is an important limiting factor in SPM-based systems. In multiprobe setups, especially when working with biological samples, this drawback can make impossible to conduct certain experiments. In this work, we present a feedfordward controller based on bang-bang and adaptive controls. The controls are based in the difference between the maximum speeds that...

Measurement and verification are one of the prime stages in the entire course of geometrical products in new generation of geometrical product specifications (GPS) standard. Like other kinds of form tolerances, flatness error is one of the important characteristics affecting the functionality and quality of machined components; sufficient efforts have long been made to determine the flatness er...

this paper proposes a new method of gain scheduling control design for a nonlinear system which is described as linear parameter varying form. a performance measure based on linear matrix inequality is introduced. to consider stability and performance measures in design process, the h∞ loop-shaping method is used to design the local controllers, which can be described as state feedback observer...

Zusammenfassung Für lineare Systeme ist die differenzielle Flachheit gleichbedeutend mit der Steuerbarkeit und damit einfacher als im nichtlinearen Fall festzustellen. In diesem Beitrag wird für lineare SISO-Systeme gezeigt, wie die differenzielle Flachheit bei der Trajektorienplanung, dem VorsteuerungsEntwurf und der Synthese von Folgeregelungen in den Koordinaten der Regelungs-Normalform ange...

The aim of this paper is to present some recent developments and hints for future researches in control inspired of flatnessbased ideas. We focus on motion planning: Steering a system from one state to another. We do not consider stabilization and trajectory tracking. We explain how explicit trajectory parameterization, a property that is central for flat systems, can be useful for the feed-for...

Due to their compliant structure, industrial robots without precision-enhancing measures are only a limited extent suitable for machining applications. Apart from structural, thermal and bearing deformations, the main cause structure is backlash of transmission drives. This paper proposes method improve trajectory tracking accuracy by using secondary encoders applying feedback flatness based fe...

In this paper we address a decentralized neighbor-based formation tracking control of multiple quadrotors with leader–follower structure. Different from most the existing work, controller is given in one loop without distinguishing motion and attitude by means theory flatness. order to achieve an aggressive tracking, high-order states neighbors are estimated using proposed extended finite-time ...