The paper presents analytical and practical studies concerning the control problems of a group of Wheeled Mobile Robots (WMRs) subject to physical constraints. Firstly, controllers for achieving trajectory tracking for kinematic unicycle-like and skidsteering mobile robots with restricted control inputs are established. Next, the underlying tracking controllers are applied for group control und...

in this paper the design of a biped robot actuated with shape memory alloy (sma) springs with minimum degrees of freedom is presented. sma springs are a class of smart materials that are known for their high power to mass and volume ratios. it was shown that utilizing spring type of smas have many advantages as large deformation, smooth motion, silent and clean movement compared to ordinary typ...

The paper considers spacecraft motion planning based on the use of safe positively invariant sets. In this approach, a connectivity graph is constructed between a set of forced equilibria, forming a virtual net that is centered around a nominal orbital position. The connectivity between two equilibria is determined based on safe positively invariant sets in order to guarantee that transitions b...

Haptic devices have the capability to offer good solutions in terms of usability and accuracy related to touch feedback on immersive virtual environments (IVEs). However, there are very few affordable devices to perform natural interaction in a 3D space and some do not represent a suited solution for the common ergonomic and stimuli-meaningfulness issues. In this article, we present a wireless ...

We demonstrate applications of a new actuator, the Haplug, in dynamic virtual environments. The haplug is a linear voice coil motor packaged between springs in a plug-like casing. Response and bandwidth of the haplug are optimized for haptic interactions, and tuned by the motor inertia and spring stiffness. A pair of haplugs is mounted on the hand-tracking controllers of HTC Vive and renders a ...

This paper describes the development of linear parameter varying (LPV) models and an LPV-H∞ controller for one degree of freedom (DoF) electro-hydraulic systems. A virtual set-up consists of a hydraulic actuator driven by a servovalve and supplied from a constant-pressure power unit. The LPV models are derived based on two techniques: black-box modeling and the analytical description of the sys...

This work demonstrates the synthesis and design of a 2-DOF (Degrees Of Freedom) parallel haptic device intended for use in virtual simulation of medical procedures, e.g., epidural injection. The process involved choosing a right kinematic architecture of the mechanism, calculation of the end-effector forces, CAD modeling, stress analysis and a rapid prototyping of the device. We chose a pantogr...

This paper describes the modeling, simulation, and control of an inverted, ceiling-mounted Stewart platform, designed to be a one-person motion simulator. The dynamic equations of the Stewart platform are derived using the virtual work principle. It is shown by simulations that the leg dynamics can be neglected. A model of the electrohydraulic actuator is derived and then veri ed using experime...

This paper addresses the experimental identification of a servo actuator which is used in many industrial applications. Because the system consisted of electrical and mechanical components, the behavior of the system was nonlinear. In addition, the under load behavior of this servo was different. The load torque was considered as the input and a two input-one output model was presented for t...