Motion Control Techniques Research Articles

Kinetics of monolayer MoS2-encapsulated nanobubbles on hexagonal boron nitride substrates

Understanding the kinetics of nanobubbles encapsulated by ultrathin two-dimensional (2D) layered van der Waals crystal membranes on atomically flat substrates is important to the applications of 2D materials and the pursuit of 2D nanobubble technologies. Here, we investigate the controlled motion of monolayer molybdenum disulfide (MoS2)-encapsulated nanobubbles on flat hexagonal boron nitride substrates using atomic force microscopy (AFM). Our study reveals a distinct transition from standstill bubble deformations to stable, stepwise bubble translations on flat substrates. The membrane tension-dominated 2D nanobubble behaves like an elastic soft body in its collision interaction with the AFM tip. This delicate motion-control technique enables neighboring 2D nanobubbles to move closer and eventually coalesce into larger nanobubbles. These findings pave the way for high-precision manipulation of nanobubbles and facilitate the exploration of their emerging applications.

Istraživanje mehaničkog dizajna robotske hvataljke za inteligentno upravljanje pomoću jeftinog senzora

With the advent of Industry 4.0, there is a growing need for intelligent and automated robotic systems capable of performing complex tasks in the unknowen environments. This work focuses on the development of mechanical design for a robotic gripper and the implementation of intelligent manipulation for picking a target using a FANUC robot platform. The proposed method combines computational mechanics for the gripper, advanced motion control techniques, and a grasping control strategy to enable the robot arm to accurately and efficiently identify and pick a target object. To validate our approach, several experimental validations are conducted in various scenarios. It is well-acknowledged that the proposed work is feasible, effective, and applicable for a wide range of industrial applications.

Real-world effectiveness and safety of stereotactic body radiotherapy for liver metastases with different respiratory motion management techniques.

Stereotactic body radiotherapy (SBRT) has been firmly established as atreatment choice for patients with oligometastases, as it has demonstrated both safety and efficacy by consistently achieving high rates of local control. Moreover, it offers potential survival benefits for carefully selected patients in real-world clinical settings. Between January 2008 and May 2020, atotal of 149 patients (with 414 liver metastases) received treatment. The Active Breathing Coordinator device was used for 68 patients, while respiratory gating was used for 65 and abdominal compression was used for 16patients. The most common histological finding was colorectal adenocarcinoma, with 37.6% of patients having three or more metastases, and 18% having two metastases. The prescribed dose ranged from 36 to 60 Gy, delivered in 3-5fractions. Local control rates at 2 and 3years were 76.1% and 61.2%, respectively, with no instances of local recurrence after 3years. Factors negatively impacting local control included colorectal histology, lower prescribed dose, and the occurrence of new liver metastases. The median overall survival from SBRT was 32months, with the presence of metastases outside the liver and the development of new liver metastases after SBRT affecting survival. The median disease-free survival was 10months. No substantial differences in both local control and survival were observed between the respiratory motion control techniques employed. Treatment tolerance was excellent, with only one patient experiencing acute gradeIV thrombocytopenia and two patients suffering from ≥ gradeII chronic toxicity. For radical management of single or multiple liver metastases, SBRT is an effective and well-tolerated treatment option. Regardless of the technology employed, experienced physicians can achieve similarly positive outcomes. However, additional studies are required to elucidate prognostic factors that can facilitate improved patient selection.

Implementation and Analysis of Motion Control Techniques on an Industrial 7 DOF Robotic Manipulator

With the quest for modernization in robotics motion control of robot manipulators is an area of active research. In motion control, inverse trajectory application is the most adopted solution which is further improved by considering the effect of external forces of the environment. The impact of external force involves dynamic modelling of the system and force control, impedance control, and admittance control techniques are adopted for the solution. This research implements the simulation and more precise visualization of the real-life manipulator under the rules of kinematics and dynamics on a 7 Degree of Freedom manipulator. The objective of this research is to implement motion control techniques: Forward Kinematics, Inverse kinematics, and Trajectory tracking using MATLAB Robotic System Toolbox and analyze the results obtained. These simulations can an effective tools for tuning the motion of robotics by varying the control parameter in simulation and then implementing them in physical hardware.

Low-power deep learning edge computing platform for resource constrained lightweight compact UAVs

Unmanned Aerial Vehicles (UAVs), which can operate autonomously in dynamic and complex environments, are becoming increasingly common. Deep learning techniques for motion control have recently taken a major qualitative step since vision-based inference tasks can be executed directly on edge. The goal is to fully integrate the machine learning (ML) element into small UAVs. However, given the limited payload capacity and energy available on small UAVs, integrating computing resources sufficient to host ML and vehicle control functions is still challenging. This paper presents a modular and generic system that can control the UAV by evaluating vision-based ML tasks directly inside the resource-constrained UAV. Two different vision-based navigation configurations were tested and demonstrated. The first configuration implements an autonomous landing site detection system, tested with two models based on LeNet-5 and MobileNetV2, respectively. This allows the UAV to change its planned path accordingly and approach the target to land. Moreover, a model for people detection based on a custom MobileNetV2 network was evaluated in the second configuration. Finally, the execution time and power consumption were measured and compared with a cloud computing approach. The results show the ability of the developed system to dynamically react to the environment to provide the necessary maneuver after detecting the target exploiting only the constrained computational resources of the UAV controller. Furthermore, we demonstrated that moving to the edge, instead of using cloud computing inference, decreases the energy requirement of the system without reducing the quality of service.

A study of possible drift trajectories of a calibrated solid body inside the ISS pressurized cabin during the conduct of experiment Vector-T

The paper discusses methodological support for space experiment Vektor-T slated to be conducted in the Russian Segment of the International Space Station (ISS RS). The objective of the space experiment is to obtain additional information needed to improve the ISS motion control techniques based on the data from tracking the drift of calibrated solid body inside the ISS pressurized cabin. The paper provides the results of estimation of possible drift trajectories depending on the condition of the Earth atmosphere, positions of the steerable structural elements of the ISS and the location of the launch point with respect to the ISS center of mass. It reviews methodological issues involved in planning the space experiment sessions, their conduct and processing of the results. Key words: space experiment, micro-accelerations, pressurized cabin, calibrated body, drift.

Analysis of normal lung irradiation in radiosurgery treatments: a comparison of lung optimized treatment (LOT) on cyberknife, 4D target volume on helical tomotherapy, and DIBH on linear accelerator.

Quantitative retrospective analysis of the normal lung irradiation due to the variations of the ITV volume based on the techniques used for upper lobe (UL), mid lobe (ML), and lower lobe (LL) lung tumours when used with 2-view, 1-view, 0-view based LOT technique on Cyberknife, AveIP on Helical Tomotherapy, and DIBH on VMAT systems. In the treatment of lung tumours, patients medically inoperable or those who are unwilling to undergo surgery have the option to be treated using radiation therapy. There are many motion control techniques available for the treatment of the moving target, such as movement encompassment, respiratory gating, breath-hold, motion reduction, and tumour monitoring. ITV generation is dependent on technique and hence the volume of the PTVs will differ based on the technique used. This study aimed to determine the influence of these ITVs on the irradiated normal lung volume for UL, ML, and LL lung tumours for 23 patients. The mean difference in the PTV volumes generated with the 0-view technique was significant with that of 2-view and DIBH techniques (p-value < 0.04). The mean difference in the PTV volumes generated by 2-view and DIBH was small for UL, ML, and LL tumours. V5 of the combined lung with the 0-view method was 5% compared to the 2-view method for UL tumours (p-value = 0.04) and the same was 9.5%, and 16.8% for ML and LL tumours (p-value < 0.04). In contrast to all other techniques, lung volume parameters V5, V10, V20, and V30 for the 0-view technology were consistently higher irrespective of the tumour location in the lung. The observed maximum mean lung dose (MLD) was 6.2Gy ± 2.7Gy with the 0-view technique and the minimum was 3.85Gy ± 1.75Gy with the DIBH technique. The difference in MLD between DIBH and 2-view was negligible (p-value = 0.67). The MLD increased for LL tumours from 4Gy to 6.5Gy from the 2-view to 0-view technique (p-value = 0.009). There was a significant increase in MLD for LL tumours with the 0-view technique compared to AveIP (1.9Gy, p-value = 0.04) and DIBH (2.0Gy, p-value = 0.003) technique. For ML and UL tumours, except for 0-view and 1-view, the difference in the MLD between the rest of the methods was not significant (p-value > 0.11). In the treatment of lung tumour patients with SBRT, this study has demonstrated 2-view with Cyberknife and DIBH with VMAT treatment techniques have optimal normal lung tissue sparing. There was a significant increase in the average lung volume receiving 5%,10%, 20%, and 30% dose when comparing the 1-view, 0-view, AveIP, and DIBH techniques to the 2-view technique. However, DIBH with VMAT was dosimetrically advantageous for ML and LL tumours, while providing significantly shorter treatment times than any other technique studied.

Navigation and motion control techniques for surface unmanned vehicle and autonomous ground vehicle: a review

An excellent navigation, guidance, and control (NGC) system had a high impact on trajectory tracking and the following scenarios. Both scenarios will include the heading, tangent, and velocity parameters in the computation. However, the control system design problem is not a new issue in the unmanned surface vehicle (USV) and autonomous ground vehivle (AGV) due to this constraint faced by many researchers since early these autonomy developments. Hence, this paper listed and emphasizing the techniques, including techniques implementation, strength, and the algorithm's constraints, a fusion of several techniques implemented for vehicle's stability, a turning ahead, and heading estimation. This paper concerns the similar algorithm used in the USV and AGV. Most of the selected techniques are basic algorithms and have been frequently implemented to control both vehicles' systems. Previous research shows pure pursuit guidance is the most popular technique in AGV to control the degree-of-freedom (DOF) velocity and the dynamic rate (sway, surge, and yaw). Simultaneously, the line of sight (LOS) controller is very compatible with controlling the movement of the USV. In conclusion, the technique's simulation test needs further research that will expose in the actual situation.

Performance Assessment of an Electric Power Steering System for Driverless Formula Student Vehicles

In the context of automated driving, Electric Power Steering (EPS) systems represent an enabling technology. They introduce the ergonomic function of reducing the physical effort required by the driver during the steering maneuver. Furthermore, EPS gives the possibility of high precision control of the steering system, thus paving the way to autonomous driving capability. In this context, the present work presents a performance assessment of an EPS system designed for a full-electric all-wheel-drive electric prototype racing in Formula Student Driverless (FSD) competitions. Specifically, the system is based on the linear actuation of the steering rack by using a ball screw. The screw nut is rotated through a belt transmission driven by a brushless DC motor. Modeling and motion control techniques for this system are presented. Moreover, the numerical model is tuned through a grey-box identification approach. Finally, the performance of the proposed EPS system is tested experimentally on the vehicle through both sine-sweep profiles and co-simulated driverless sessions. The system performance is assessed in terms of reference tracking capability, thus showing favorable results for the proposed actuation solution.

A Study of Optimized EEG Signal Induction/Extraction Techniques for Basic Motion Control of Personal Robots for Physically Impaired Users

When interfaces utilizing EEG signals are used, these signals can be induced through diverse association techniques. In the present article, differences in recognition performance of the systems related to robot control techniques according to diverse association techniques have been analyzed. For this purpose, elements that can affect the performance other than association techniques were excluded as much as possible, and the focus was placed on the performance analysis per association technique. According to the study results of the present article, the movement association technique based on gestures showed the highest recognition performance in the robot control system for multiple users. In the robot control system for single users, hearing-based phonation association is considered to show the highest recognition performance. In the study results of the present article, superior recognition performance is considered to be derived than the recognition performance displayed by existing systems when applied to the robot control area utilizing EEG signals.

Manufacturing a Plotter Printer with Computer Numerical Control Based Pen Ink Using CoreXY Mechanisms

In the process of printing images, a high-quality plotter printer is required to obtain better printed images. This causes the costs incurred to purchase a plotter printer become even higher along with the quality of the printout. In addition, the use of original plotter printer ink is significantly more expensive than that of the non-original ink. Therefore, this paper proposes a pen based computer plotter printer design using the CoreXY framework. This framework is based on a 2D in-axis motion control technique using a single continuous belt for both axes. To evaluate the performance of the proposed design, the level precision for vector and raster modes are measured using the Mean Absolute Percentage (MAPE). Based on the results of precision measurements, it was found that the printer prototype designed to produce high-precision images with affordable pen ink costs and can process digital instructions from a computer using Computer Numerical Control (CNC).

Full-Dimensional Intuitive Motion Mapping Strategy for Minimally Invasive Surgical Robot With Redundant Passive Joints

AbstractAdding redundant passive joints to a robotic arm is an effective way to make the robot overcome the inherent incision constraint of minimally invasive surgery (MIS). However, due to the limited motion accuracy, it is difficult to realize full-dimensional intuitive motion based on traditional multi-axis coordinated control technology in this kind of MIS robots. To solve this problem, a separated position and orientation mapping strategy for MIS robot with redundant passive joints is proposed in the paper. The position and orientation mapping of the strategy are realized by coordinate motion control and joint direct control technique, respectively. To realize the intuitive motion under this condition, an inverse motion mapping method is further proposed. Compared with the existing mapping strategy, the proposed strategy is much more compact as the orientation mapping is greatly simplified. A large number of in vivo trials based on the newly developed prototype have been conducted and results fully verify the effectiveness of the proposed strategy.

Identifying and mitigating residual vibrations in wave-based control of lumped, flexible systems

Wave-based control (WBC) is a technique for motion control of under-actuated flexible systems. It envisages actuator motion as launching a motion wave into the system, while simultaneously absorbing any wave returning from the system. For rest-to-rest motion the net launch displacement is set at half the target displacement. In absorbing the returning wave and vibrations, WBC moves the system the remaining distance to the target, with zero steady-state error. The focus of this paper is on very small residual vibrations around the target position which can endure for a long time after arrival at target. This issue was discovered through a recent development within WBC context on controlling complex two-dimensional, mass-spring, beam-like arrays. To date their existence has been unidentified. This paper investigates and interprets the nature of these vibrations, explains and identifies them based on wave ideas, and finally offers a new wave-based approach to mitigate or suppress them. It also discusses their implication, not just for WBC but for the general problem of control of flexible systems.

Motion-control techniques of today and tomorrow: a review and discussion of the challenges of controlled motion

The paper states that continued progress in integrated mechatronic design and novel actuator technologies has created new challenges for motion control technologies.

Vision-Based Multirotor Following Using Synthetic Learning Techniques.

Deep- and reinforcement-learning techniques have increasingly required large sets of real data to achieve stable convergence and generalization, in the context of image-recognition, object-detection or motion-control strategies. On this subject, the research community lacks robust approaches to overcome unavailable real-world extensive data by means of realistic synthetic-information and domain-adaptation techniques. In this work, synthetic-learning strategies have been used for the vision-based autonomous following of a noncooperative multirotor. The complete maneuver was learned with synthetic images and high-dimensional low-level continuous robot states, with deep- and reinforcement-learning techniques for object detection and motion control, respectively. A novel motion-control strategy for object following is introduced where the camera gimbal movement is coupled with the multirotor motion during the multirotor following. Results confirm that our present framework can be used to deploy a vision-based task in real flight using synthetic data. It was extensively validated in both simulated and real-flight scenarios, providing proper results (following a multirotor up to 1.3 m/s in simulation and 0.3 m/s in real flights).

Existence Conditions and General Solutions of Closed-form Inverse Kinematics for Revolute Serial Robots

This study proposes a method for judging the existence of closed-form inverse kinematics solutions based on the Denavit–Hartenberg (DH) model. In this method, serial robots with closed-form solutions are described using three types of sub-problems from the viewpoint of solving algebraic equations. If a serial robot can be described using these three types of sub-problems, i.e., if the inverse kinematics problems can be solved by several basic problems, then there is a closed-form solution. Based on the above method, we design a set of universal closed-form inverse kinematics solving algorithms. Since there is a definite formula solution for the three types of sub-problems, the joint angles can be rapidly determined. In addition, because the DH parameters can directly reflect the linkage of the robot, the judgment of the sub-problems is also quick and accurate. More importantly, the algorithm can be applied to serial robots with low degrees of freedom. This enables the algorithm to not only quickly and accurately solve inverse kinematics problems but also to exhibit high universality. This proposed theory improves the existence conditions for closed-form reverse solutions and further promotes the development of motion control techniques for serial robots.

Autonomous control for multi-agent non-uniform spraying

The use of computer controlled swarms of UAVs for crop spraying enables non-uniform coverage of high precision and time efficiency. For this purpose an algorithmic control method for autonomous UAV swarm spraying, based on multi-agent area coverage method Heat Equation Driven Area Coverage (HEDAC), is proposed. Motion control relies on suitable spraying model which enables of multi-agent spraying simulations for arbitrary agent’s trajectories. The HEDAC control method was tested in comparison with conventional (Lawnmower) and state-of-the-art (SMC) path planning methods on three numerical tests: two based on simple geometries and algebraically defined spraying goal densities, and one based on a real-world crop disease map. Additionally, the effects of spraying tool design (number of nozzles and their spraying density) on spraying accuracy were analyzed, with results consistently illustrating the direct causation between tool precision and overall spraying error. The results of the testing have shown HEDAC control to be significantly faster than Lawnmower (approximately 35%–65% less time needed) and SMC (approximately 15%–50% less time needed) in achieving convergence, while producing spraying density of comparable accuracy. Moreover, HEDAC spraying typically mitigates over-spraying by approximately 3%–8% when compared with conventional path planning. In additional tests, it is shown that an implementation of collision avoidance technique for HEDAC motion control provides collision-free UAV swarm spraying. The effect of HEDAC collision avoidance control on the spraying convergence rate and accuracy is practically insignificant. It may be concluded that in real-world application HEDAC controlled UAV spraying swarms are expected to significantly outperform UAVs operating with existing path planning methods.

Motion control technique on rough terrain for four-wheel type robot with rolling shaft

Motion control technique on rough terrain for four-wheel type robot with rolling shaft

The Applications of Compliant Motion Control Technique on 6-DOF Hydraulic Parallel Mechanism

Most interaction control formulations focused on electrically driven parallel mechanism. In this paper, the combining practice applications of compliant motion control technique on six degrees of freedom (6-DOF) hydraulic parallel mechanism (HPM) are investigated. According to the manipulation task specification and hydraulic control system characteristics, three different compliant motion control schemes are presented in three typical application scenarios, respectively: a parallel position/force control scheme in the joint space coordinate for train curve negotiation performance test, a hybrid position/force control scheme with the internal force suppression for shaking table with actuation redundancy, and a hybrid impedance control scheme for auto-docking mechanism based on force and vision. The feasibility and effectiveness of the proposed schemes were verified through a series of experiments. It showed that the 6-DOF HPM achieves good compliant behavior by applying the proposed compliant motion control techniques. These schemes could also be extended to other applications where the compliant motion of the 6-DOF HPM is required.

Diverting and Sorting Mobile Robotic Table for Motion Control Testing

This article is about the design and construction of a Diverting and Sorting mobile robot table for testing motion control techniques, the robot consists of nine modules with two degrees of freedom each one in three times three matrix configuration; a table with dual rack gear track in bottom move between modules, combined control of each module allows the transport of objects. Computer vision techniques are employed in this case a Pinhole camera model for detection and location of the carry objects. Each of the characteristics of the design and construction of the parts that form the mechanical system are explained in detail. The table design includes high quality and low-cost materials. At finally, the robotic table is verified with different techniques of control, for example follower desired path. The result shows a difference between the real path and the desired path that will be calculated under the quadratic error function.