Dmitry Malyshev

Bio: Dmitry Malyshev is an academic researcher from Belgorod State Technological University. The author has contributed to research in topics: Workspace & Parallel manipulator. The author has an hindex of 4, co-authored 32 publications receiving 62 citations.

Finite-Time Robust Admissible Consensus Control of Multirobot System Under Dynamic Events

Abstract: This article addresses the problem of event-based consensus in a leader–follower multiagent system framework prone to external bounded disturbance. The proposed approach has three parts. The first part defines a novel measurement error based on sliding surface for super-twisting sliding-mode controller. The Lyapunov stability analysis is then used to derive a dynamic event-triggering condition for control updates. The event-based control updates guarantee stability along with the desired consensus amongst agents (robots). The second part derives a bound on reaching time to the sliding surface, thereby guaranteeing finite-time consensus control for each agent. The third part guarantees the admissibility of event-based control updates for each agent. The robustness of the proposed approach is validated through simulation and real-time experiments using three Pioneer P3-DX mobile robots in a multiagent framework. The real-time experimental results prove the reduction in computational burden of the entire system as control updates for two followers are found to be approximately $\text{28.33}\%$ and $\text{23.33}\%$ , respectively, in the presence of disturbances.

Approaches to the Determination of the Working Area of Parallel Robots and the Analysis of Their Geometric Characteristics

Abstract: The article presents and experimentally confirms two approaches to the problem of determining the working area of parallel robots using the example of a planar robot DexTAR with two degrees of freedom. The proposed approaches are based on the use of constraint equations of coordinates. In the first approach, the original kinematic equations of coordinates in the six-dimensional space (two coordinates describing the position of the output link and four coordinates – the rotation angles of the rods) followed by projecting the solution onto the two-dimensional plane is used. In the second approach, the system of constraint equations is reduced to a system of inequalities describing the coordinates of the output link of the robot, which are solved in a two-dimensional Euclidean space. The results of the computational experiments are given. As an algorithmic basis of the proposed approaches, the method of non-uniform coverings is used, which obtains the external and internal approximation of the solution set of equality/inequality systems with a given accuracy. The approximation is a set of boxes. It is shown that in the first approach, it is more efficient to apply interval estimates that coincide with the extremes of the function on the box, and in the second approach, grid approximation performs better due to multiple occurrences of variables in inequalities.

Optimal Design of a Parallel Manipulator for Aliquoting of Biomaterials Considering Workspace and Singularity Zones

Abstract: This article presents the concept of a robotic system for aliquoting of biomaterial, consisting of a serial manipulator in combination with a parallel Delta-like robot. The paper describes a mathematical formulation for approximating the geometric constraints of the parallel robot as a set of solutions to a system of nonlinear inequalities. The analysis of the workspace is carried out, taking into account singularity zones, using a method based on the analysis of the Jacobian matrix of the mechanism and the interference of links. An optimal design procedure is proposed for the dimensional synthesis based on a criterion for maximizing the volume of the workspace, taking into account the ambiguity of the solution of the inverse kinematics. Simulation results are reported and discussed to propose a suitable design solution.

Conceptual Design and Control of a Sitting-Type Lower-Limb Rehabilitation System Established on a Spatial 3-PRRR Parallel Manipulator

Abstract: The conceptual design of a new sitting-type lower-limb rehabilitation robot along with simplified motion control for its passive range of motion therapies is put forth here The suggested system’s design is demonstrated and verified using computer-based numerical simulations For this, the desired motion trajectory is generated with the help of a clinically obtained gait data-set The robustness of the proposed simplified motion control scheme is verified with the variation of the physical parameters of the patients’ limb

Optimization Algorithm for Approximating the Solutions Set of Nonlinear Inequalities Systems in the Problem of Determining the Robot Workspace

Abstract: This paper is devoted to the problem of determining the workspace of robots. We consider an approach to the development of a numerical method for approximating the set of solutions of a system of nonlinear inequalities based on the concept of non-uniform coverings. An approach is proposed based on the transformation of non-uniform covering sets into a set of partially ordered sets of integers to reduce computational complexity. An algorithm for transforming boxes of a covering set is presented. The approach has been tested for a 3-RPS robot. The results of the mathematical simulation and analysis of the effectiveness of the proposed approach based on an estimate of the reduction in the amount of numbers describing the covering set are presented.

A Survey on Event-Triggered Sliding Mode Control

Abstract: Event-triggered controllers are well known for guaranteeing the desired stability for a sampled-data system with minimum resource utilization. Over the past decade, the study has revealed that the overall performance improvement for a sampled-data system can be achieved by replacing the time-based sampling with an event-triggered one. The design of sliding mode control (SMC) in the event-triggering framework has also shown similar outcomes, especially for uncertain systems. There are different design strategies for event-triggered SMC available in the literature for networked dynamical systems that are potentially affected by uncertainties and transmission delays. The purpose of this survey article is to present the state of the art on event-triggered SMC and familiarize the readers with the design techniques with their pros and cons, since this will be very helpful to the researchers and engineers for implementing SMC using event-based feedback strategies.

Finite-time super twisting sliding mode controller based on higher-order sliding mode observer for real-time trajectory tracking of a quadrotor

Abstract: The main focus of this study is to develop a finite-time super-twisting sliding mode control strategy for the quadrotor based on a higher-order sliding mode observer (HOSMO). 12 state variables are required to describe the motion of the quadrotor, of which six state variables, namely the position, altitude, and orientation, are assumed to be obtained from the sensors. The remaining state variables, i.e. the linear and angular velocities, are determined using the HOSMO. Besides, the HOSMO aids in determining the unknown bounded lumped disturbances acting on the quadrotor. The output of the HOSMO is utilised for implementing the finite-time super-twisting sliding mode controller (FTSTSMC). The proposed FTSTSMC ensures finite-time convergence of tracking error with chattering attenuation. The chattering analysis for a super-twisting algorithm is presented in this work. Moreover, the overall system stability is investigated using the Lyapunov theory, and an expression for the time of convergence of the tracking and estimation error is presented. The effectiveness of the proposed methodology is established using numerical simulations and its performance is compared to a finite-time sliding mode observer coupled with a combination of proportional–integral–derivative and continuous sliding-mode controller. This is then validated in real-time using the DJI Matrice 100.

Uncertainty Compensator and Fault Estimator-Based Exponential Supertwisting Sliding-Mode Controller for a Mobile Robot

Abstract: This work proposes a novel event-triggered exponential supertwisting algorithm (ESTA) for path tracking of a mobile robot. The proposed work is divided into three parts. In the first part, a fractional-order sliding surface-based exponential supertwisting event-triggered controller has been proposed. Fractional-order sliding surface improves the transient response, and the exponential supertwisting reaching law reduces the reaching phase time and eliminates the chattering. The event-triggering condition is derived using the Lipschitz method for minimum actuator utilization, and the interexecution time between two events is derived. In the second part, a fault estimator is designed to estimate the actuator fault using the Lyapunov stability theory. Furthermore, it is shown that in the presence of matched and unmatched uncertainty, event-trigger-based controller performance degrades. Hence, in the third part, an integral sliding-mode controller (ISMC) has been clubbed with the event-trigger ESTA for filtering of the uncertainties. It is also shown that when fault estimator-based ESTA is clubbed with ISMC, then the robustness of the controller increases, and the tracking performance improves. This novel technique is robust toward uncertainty and fault, offers finite-time convergence, reduces chattering, and offers minimum resource utilization. Simulations and experimental studies are carried out to validate the advantages of the proposed controller over the existing methods.

Approaches to the Determination of the Working Area of Parallel Robots and the Analysis of Their Geometric Characteristics

Abstract: The article presents and experimentally confirms two approaches to the problem of determining the working area of parallel robots using the example of a planar robot DexTAR with two degrees of freedom. The proposed approaches are based on the use of constraint equations of coordinates. In the first approach, the original kinematic equations of coordinates in the six-dimensional space (two coordinates describing the position of the output link and four coordinates – the rotation angles of the rods) followed by projecting the solution onto the two-dimensional plane is used. In the second approach, the system of constraint equations is reduced to a system of inequalities describing the coordinates of the output link of the robot, which are solved in a two-dimensional Euclidean space. The results of the computational experiments are given. As an algorithmic basis of the proposed approaches, the method of non-uniform coverings is used, which obtains the external and internal approximation of the solution set of equality/inequality systems with a given accuracy. The approximation is a set of boxes. It is shown that in the first approach, it is more efficient to apply interval estimates that coincide with the extremes of the function on the box, and in the second approach, grid approximation performs better due to multiple occurrences of variables in inequalities.