Altay Zhakatayev

• Doctor of Philosophy
• Instructor at Nazarbayev University

In this paper, we propose one possible theoretical limit on the maximum ground speed of wheeled vehicles.

This study investigates the aerodynamic and aeroacoustic performance of a novel two-stage two-bladed coaxial propeller that is axially and angularly spaced. Aerodynamic propulsive thrust and efficiency are validated and evaluated using a Reynolds-averaged Navier–Stokes computational fluid dynamics (CFD) model for the two-bladed APC27x13 propeller....

This paper aims to present a detailed Digital Twin (DT) framework indicating important implementation steps and providing insights into DT technology that improves operational efficiency, optimizes performance, and creates a user-friendly platform for real-time monitoring. This project is conducted in collaboration with TechnoGroupService (TGS) com...

In the ESGI-156 project together with Ålesund Brannvesen we develop a model for response times to fire incidents on publicly available data for Ålesund. We investigate different scenarios and a first step towards an interactive software for illustrating the response times.

The material’s stiffness plays a crucial role in tactile sensors and stiffness controllers of robot joints, facilitating safe and effective robot-environment interactions. Conventional controllers or sensors require a priori information about stiffness modulation to efficiently control environmental collisions and reduce their detrimental effects....

We present a first-order recursive approach to sensitivity analysis based on the application of the direct differentiation method to the inverse Lagrangian dynamics of rigid multibody systems. Our method is simple and efficient and is characterized by the following features. Firstly, it describes the kinematics of multibody systems using branch con...

In this work, we present a simple framework to synthesize human motion. Our main goal is to propose a methodology tailored for inexperienced users to initiate their research in human motion simulation and human motion trajectory optimization. The novelties of the work include the following. First, trigonometric splines are used instead of tradition...

In this work, by using the assumptions that wavelength is much smaller than charge separation distance of an electric dipole, which in turn is much smaller than a distance up to the point of observation, the new results for radiation of an electric dipole were obtained. These results generalize and extend the standard classical solution, and they i...

In this short paper, it is shown that Lorenz gauge condition leads to disappearance of long-range longitudinal electric wave emitted by an arbitrary electrical system. In any other gauge, longitudinal electric wave would be non-negligible. Implications of the obtained results are discussed.

Negative stiffness honeycombs (NSHs) have multiple advantages compared to traditional honeycomb structures. These advantages include recoverable elastic buckling, shock absorption, and vibration isolation. As a result, NSHs have great potential in applications such as acoustic wave guiding, shape morphing, design of impact-protection devices and ro...

Tensegrity structures have unique features such as low mass to payload ratio, strength, and robustness. Therefore, they present great potential in robotics, aerospace, and civil engineering. The dynamics of tensegrity robots is highly nonlinear and constrained. As a result, their modeling, simulation, state estimation, and control are non-trivial....

Variable stiffness actuated (VSA) robots are expected to play an important role in physical human-robot interaction, thanks to their inherent safety features. These systems can control the position and stiffness concurrently by incorporating two or more actuators for each joint. Unfortunately, the need for extra sensors to measure the state of thes...

Tensegrity structures, emerged initially as an art form, have recently gained substantial interest among engineering researchers. The distinctive attribute of these structures is using pretensioned tensile elements connected to rigid bars to establish equilibrium of the whole structure. Thanks to these elements, tensegrity structures are lightweigh...

Energy-aware motion planning for robotic systems has received increasing attention during recent years, due to environmental and economic reasons. This paper presents a framework for defining and solving different types of optimal control problems for variable stiffness actuated robots. These robots can store and release energy during task executio...

In this paper, radiation due to standing wave currents were considered for the electric dipole. Assumptions that wavelength is much smaller than the dipole separation distance, which is in turn much smaller than the distance to the point of observation, were employed. Results indicate that the electric dipole, which now essentially is a linear ante...

In this work we further advance theoretical investigation of radiation by the electric dipole under the assumption that wavelength is much smaller than charge separation distance of an electric dipole, which in turn is much smaller than a distance up to the point of observation. Specifically, two cases were considered. In the first case phase delay...

In this work by using the assumptions that wavelength is much smaller than charge separation distance of an electric dipole, which in turn is much smaller than a distance up to the point of observation, the new results for radiation of an electric dipole were obtained. These results generalize and extend the standard classical solution, and they in...

Variable-stiffness actuation exhibits promising features for obtaining human-like behavior and safer human robot physical interaction. Task planning and closed-loop control of these systems pose many challenges due to their complicated structure, and the need of satisfying many constraints during task execution. This paper introduces a framework fo...

In this paper we considered divergence of electric and of magnetic fields for four cases: classical point charge, classical continuous charge, relativistic point and relativistic continuous charges. Results for classical and relativistic point charges are the same as in literature, i.e. Gauss's law is valid. However results for time-varying classic...

A branch of robotics, variable impedance actuation, along with one of its subfields variable stiffness actuation (VSA), is gaining momentum recently. There have been many thorough studies earlier in the design and recently in the control of these systems. The performance of these systems is mainly limited by their physical constraints, such as actu...

Variable impedance actuation is a new paradigm in robotics, which aims to reach the safety, dexterity and efficiency level of biological systems. Recent advances in the control of variable impedance actuated (VIA) robots offer new venues for the integration of additional types of actuation elements to these systems. In this work, we present our fea...

This paper proposes a method to determine the optimal value of design parameters in robots driven by variable-stiffness actuators. The method consists of setting up a nonlinear optimization problem, the solution of which determines the optimal control sequence, and, at the same time, the optimal values of the parameters. As a case study, we analyze...

Gauss's law in integral form states that closed surface integral of electric field is proportional to net charge present within the volume bounded by this closed surface. Gauss's law in differential form states that divergence of electric field is proportional to charge's volume density. From Gauss's law it is concluded that in vacuum, where no ele...

Variable stiffness actuation has recently attracted great interest in robotics, especially in areas involving a high degree of human–robot interaction. After investigating various design approaches for variable stiffness actuated (VSA) robots, currently the focus is shifting to the control of these systems. Control of VSA robots is challenging due...