Benzene adsorption at the aqueous (011) α-quartz interface : is surface flexibility important?

Atomistic simulations of molecular adsorption onto inorganic substrates under aqueous conditions can be used to guide the rational design of new materials, fabricated using biomimetic methods. The success of such work depends critically on the model used. Here, we investigate the impact of using a rigid structural model of the (0 1 1) ?-quartz surface, over a fully flexible model, on the calculated free energy change in the adsorption of a single molecule of benzene (a simple analogue of the amino acid phenylalanine) from liquid water. Subtle differences in the mobility of the adsorbate close to the surface result in the free energy of adsorption being overestimated by the rigid model, relative to the fully flexible case. Moreover, we find that the distribution of bound configurations of the adsorbate at their respective free energy minima is different between the two models.

Multipoint haptic mediator interface for robotic teleoperation

Despite recent advances in artificial intelligence and autonomous robotics, teleoperation can provide distinct benefits in applications requiring real-time human judgement and intuition. However, as robotic systems are increasingly becoming sophisticated and are performing more complex tasks, realizing these benefits requires new approaches to teleoperation. This paper introduces a novel haptic mediator interface for teleoperating mobile robotic platforms that have a variety of manipulators and functions. Identical master-slave bilateral teleoperation of the robotic manipulators is achieved by representing them in virtual reality and by allowing the operator to interact with them using a multipoint haptic device. The operator is also able to command motions to the mobile platform by using a novel haptic interaction metaphor rather than a separate dedicated input device. The presented interaction techniques enable the operator to perform a wide range of control functions and achieve functionality similar to that of conventional teleoperation schemes that use a single haptic interface. The mediator interface is presented, and important considerations such as workspace mapping and scaling are discussed. © 2015 IEEE.

Haptics interface for modelling and simulation of flexible cables

Virtual reality systems are becoming a must for product and process design, training practices and ergonomic analysis in many manufacturing industries. The automotive sector is considered to be the leader in applying virtual reality (VR) solutions for real-world, non-trivial, problems. Although, a number of commercial 3D engineering tools for digital mockups exist, most of them lack intuitive direct manipulation of the digital mockups. The majority of these 3D engineering tools are constrained to the interaction mainly with rigid objects which is just half the story. To bridge this gap, we have developed a haptics interface for modelling and simulation of flexible objects. The graphical and haptic user interface developed allows the creation of multiple one dimensional (1D) flexible objects, such as hoses, cables and harnesses. The user is required to provide the mechanical properties of the material such as Young's modulus, Poisson's ratio, material density, damping factors, as well as dimensional properties such as length, and inner and outer diameters of the flexible object. Flexilution solver is employed to estimate and simulate the dynamic behaviour of flexible objects in response to external user interaction, whereas Nvidia's generic physics engine is used to simulate the behaviour of rigid objects. A generic communication interface is developed to accommodate a variety of devices without the reconfiguration of the simulation platform.