Movable Platform Research Articles

Spiked Systems for Colonic Drug Delivery: Architectural Opportunities and Quality Assurance of Selective Laser Sintering.

Additive manufacturing has been a breakthrough therapy for the pharmaceutical industry raising opportunities for long-quested properties, such as controlled drug-delivery. The aim of this study was to explore the geometrical capabilities of selective laser sintering (SLS) by creating spiked (tapered-edged) drug-loaded specimens for administration in colon. Poly(vinyl alcohol) (PVA) was used as the binding material and loperamide hydrochloride was incorporated as the active ingredient. Printing was feasible without the addition of a sintering agent or other additives. Innovative printing protocols were developed to help improve the quality of the obtained products. Intentional vibrations were applied on the powder bed through rapid movements of the printing platform in order to facilitate rigidity and consistency of the printed objects. The drug-loaded products had physicochemical properties that met the pharmacopoeia standards and exhibited good biocompatibility. The behavior of spiked balls (spherical objects with prominent spikes) and their retention time in the colon was assessed using a custom ex vivo intestinal setup. The spiked balls showed favorable mucoadhesive properties over the unspiked ones. No movement on the tissue was recorded for the spiked balls, and specimens with more spikes exhibited longer retention times and potentially, enhanced bioavailability. Our results suggest that SLS 3D printing is a versatile technology that holds the potential to revolutionize drug delivery systems by enabling the creation of complex geometries and medications with tunable properties.

Novel Design of Wrist With Gripper: Type Synthesis of a 2R1T Parallel Mechanism Possessing One Actuation Degree-of-Freedom

Abstract The parallel mechanism (PM) with a configurable movable platform (CMP) holds the potential for achieving a high-response speed and high-stiffness integrated design of a gripper-wrist system. The motion of two rotations and one translation (2R1T), closely resembling the movement of a human wrist joint, is highly complex. Therefore, research on 2R1T PM with CMP remains unexplored. Additionally, a systematic method for constructing PM with CMP is also lacking. This paper proposes fundamental design principles for PM with CMP. The topological arrangements of 2R1T PM with CMP are classified according to the number of limbs, their types, and the CMP structure. The basic constraint conditions and the redundant constraint conditions of 2R1T PM are analyzed. By establishing the relationship between finite motions, joint geometric parameters, and constraint screws, a series of limb structures that provide specific constraints in finite motions are constructed. Several configuration examples of gripper-wrist mechanism are provided, which can serve as a guide for subsequent researches. The design approach of CMP is discussed. The performance advantages of such mechanisms are validated through simulation-based comparisons.

Camera-based control system of a planar cable-driven parallel robot intended for functional rehabilitation

Abstract This paper investigates a closed-loop visual servo control scheme for controlling the position of a fully constrained cable-driven parallel robot (CDPR) designed for functional rehabilitation tasks. The control system incorporates real-time position correction using an Intel RealSense camera. Our CDPR features four cables exiting from pulleys, driven by AC servomotors, to move the moving platform (MP). The focus of this work is the development of a control scheme for a closed-loop visual servoing system utilizing depth/RGB images. The developed algorithm uses this data to determine the actual Cartesian position of the MP, which is then compared to the desired position to calculate the required Cartesian displacement. This displacement is fed into the inverse kinematic model to generate the servomotor commands. Three types of trajectories (circular, square, and triangular) are used to test the controller’s compliance with its position. Compared to the open-loop control of the robot, the new control system increases positional accuracy and effectively handles cable behavior, various perturbations, and modeling errors. The obtained results showed significant improvements in control performance, notably reduced root mean square error and maximal error in terms of position.

DEVICE FOR CALIBRATION OF THE PRESSURE SENSOR OF GRANULAR BULK MATERIALS

According to the plan for the implementation of the scientific and technical work "Experimental and theoretical studies of the influence of the roll of a vertical deep container on the distribution of horizontal pressure of granular bulk material on the walls of the container" (DR No. 0121U112518), which is being carried out at the Department of Mechanical Engineering of ODABA, for further research on the pressure distribution of bulk material, a pneumatic measuring system for measuring pressure of granular material on the vertical walls of storage models was developed. Pressure measurements are indirect - based on the absolute value of the movement of the sensor platform, which perceives the pressure of the bulk material, relative to the sensor body, the amount of pressure of the bulk material on the sensor was estimated. The system is multi-channel, each measuring channel consists of a bulk material pressure sensor, a channel for measuring movement of the pressure sensor platform and a recorder of this movement. The device for calibrating the pressure sensor is designed to obtain the calibration dependence of the output signal (the air pressure in the measurement chamber with pneumatic sieves) from the input signal (the value of the uniformly distributed pressure on the sensor). The device is two connected hydraulic systems filled with water. One of them consists of a pressure chamber with a flexible membrane through which the water pressure is transmitted to the sensor, and a measuring tube with a ruler to measure the water level above the membrane. The second one is a buffer tank for water, connected to the pressure chamber of the first system by a flexible tube and can move in vertical position. Hydrosystems are interconnected, so the both of them have the same water level. The water pressure on the sensor changes by moving the buffer tank up and down. The sensor is made in accordance with the patent of Ukraine for the invention and consists of a housing connected through an annular elastic element to the sensor platform, which perceives the pressure of the bulk material. In order to exclude the impact on the measured pressure by arching in the loose material above the sensor platform, linear displacements of the sensor platform relative to the housing should not exceed 5-8 ?m. Such small movements are measured by a non-contact pneumatic gauge based on a non-differential measuring pneumatic system of the manometric type with a working air pressure in the system of 7.5-10 kPa. Air pressure in the pneumatic system is measured by alcohol manometers. The device is made in the form of a two-branch rack: one branch is a measuring branch, and the other has a screw mechanism for vertical movement of the buffer tank. The accuracy of the pressure assignment on the sensor is ± 0.1 g/cm2, and the measurement of the output signal is ± 0.5 mm

Internal scanning hyperspectral imaging system for deep sea target detection

Internal scanning hyperspectral imaging system for deep sea target detection

Base Components of the Neuro-fuzzy Control System for a Group of Mobile Robotic Platforms

Coordinating the movement of mobile robotic platforms (MRPs) in dynamic environments is a significant challenge in both civil and military applications, where large-scale transport, exploration, and task distribution are required. This research presents a neuro-fuzzy control system that integrates fuzzy logic with real-time navigation to optimize group movement. The system’s key components include data acquisition from navigation sensors such as gyroscopes, digital compasses, and lidars, along with wireless communication modules to facilitate seamless interaction and coordination among MRPs. A fuzzy logic controller, enhanced by neuro-like defuzzification, improves decision-making precision and platform synchronization. Additionally, the system incorporates advanced route planning algorithms to effectively manage group navigation, even in unpredictable and rapidly changing environments. The practical implementation is based on embedded platforms, including Raspberry Pi and microcontrollers such as STM8S003F3 and ESP32C3, which process data from sensors like the MPU-6050 gyroscope, QMC5883L compass, and YDLidar X4 lidar. This architecture was experimentally validated across real-world scenarios, demonstrating significant improvements in movement coordination, reduced response time, and enhanced operational efficiency. The system supports parallel processing and real-time optimization, making it suitable for tasks that require rapid adaptation to changing conditions. Furthermore, its scalability and flexibility make it an effective solution for real-world applications in environments that demand precise group control. The results underscore the practical value of this approach, reducing both development time and costs while improving the overall performance of MRP systems in complex operational settings. The developed neuro-fuzzy system provides a robust and scalable platform for efficient group management, making it well-suited for a wide range of dynamic, real-time applications.

A radiation therapy platform to enable upright cone beam computed tomography and future upright treatment on existing photon therapy machines.

The conventional lying down position for radiation therapy can be challenging for patients due to pain, swallowing or breathing issues. To provide an alternative upright treatment position for these patients, we have developed a portable rotating radiation therapy platform which integrates with conventional photon treatment machines. The device enables cone-beam computed tomography (CBCT) imaging of patients in an upright position, and the future delivery of therapeutic radiation. To design, manufacture, and test a device for upright radiation therapy. A collaborative partnership between physicists, engineers, radiation therapists, radiation oncologists, implementation researchers and consumers was established, to create a device that meets both the clinical and technical requirements of upright radiation therapy. The device is central to a clinical trial (ACTRN12623000498695) which will evaluate upright image quality in the context of future image guided radiation therapy for patients with lung cancer or head and neck cancer. The weight and physical constraints of the device were assessed with respect to the American civilian population. The final design was evaluated with a series of tests to characterize the angular accuracy of the platform rotation and the reproducibility of the platform setup position in a radiation treatment room. To acquire an upright CBCT, the platform movement system was synchronized to the kilo-voltage fluoroscopic imaging on an existing treatment machine. The accuracy of the synchronization was evaluated by assessing the positional reproducibility of upright CBCT imaging of a chest phantom. The platform has a weight limit of up to 125kg which is suitable for approximately 90% of males and 95% of females. The platform has physical constraints that accommodate approximately 95.6% of males and 99.6% of females: a maximum seated height of 97.5cm, a maximum hip breadth of 63.0cm, and maximum elbow to knuckle length of 46.5cm. The angular accuracy of the motion system is within ±0.15° over a full rotation, which is within the guidelines for machine movement accuracy in radiation therapy (1mm/1°). The platform is a portable device and can be reproducibly positioned in a radiation therapy treatment room with a translational range within ±0.04mm and a rotational range within ±0.025°. The CBCT imaging can reproducibly detect the position of a chest phantom with a translational uncertainty of ±0.07mm and a rotational uncertainly of ±0.22°, when imaging is acquired following a strict procedure. The upright radiation therapy platform is suitable for the evaluation of CBCT imaging in the context of image guided radiation therapy. The platform will allow the investigation of open questions in upright radiation therapy in the areas of patient experience, positional stability, anatomical changes, and treatment delivery. Improvements to the materials in the radiation beam line, synchronization with the existing treatment machine, and increasing the device weight limit are suggested prior to delivery of future upright treatments.

Mooring line materials for mini-TLP platforms

Abstract The present paper aims to compare the different types of mooring lines and materials with respect to motions and performance of a mini-Tension-Leg Platform. FloatMast®, that has been deployed in the Aegean Sea and completed a 1-year successful offshore site assessment, is a mini TLP and its structural model was used to evaluate the different mooring systems. Synthetic ropes, as alternative to wire ropes, have been introduced recently for mini TLPs, and their performance in these types of offshore platforms is of notable interest, both performance and marketwise. The simulations were conducted using DNV’s software SESAM suite and address operational as well as extreme wave conditions. The results present, for all materials, the performance of each mooring line in terms of axial tension and platform movement.

Robust Visual Landing Control of Quadrotor on a Moving Platform: A Sampled-Data Approach With Delayed Output and Disturbances

Robust Visual Landing Control of Quadrotor on a Moving Platform: A Sampled-Data Approach With Delayed Output and Disturbances

Vision-Based Optimal Landing Guidance Law for VTOL UAVs on a Moving Platform

Vision-Based Optimal Landing Guidance Law for VTOL UAVs on a Moving Platform

A "Conscious" Loss of Balance: Directing Attention to Movement Can Impair the Cortical Response to Postural Perturbations.

"Trying too hard" can interfere with skilled movement, such as sports and music playing. Postural control can similarly suffer when conscious attention is directed toward it ("conscious movement processing"; CMP). However, the neural mechanisms through which CMP influences balance remain poorly understood. We explored the effects of CMP on electroencephalographic (EEG) perturbation-evoked cortical responses and subsequent balance performance. Twenty healthy young adults (age = 25.1 ± 5 years; 10 males and 10 females) stood on a force plate-embedded moveable platform while mobile EEG was recorded. Participants completed two blocks of 50 discrete perturbations, containing an even mix of slower (186 mm/s peak velocity) and faster (225 mm/s peak velocity) perturbations. One block was performed under conditions of CMP (i.e., instructions to consciously control balance), while the other was performed under "Control" conditions with no additional instructions. For both slow and fast perturbations, CMP resulted in significantly smaller cortical N1 signals (a perturbation-evoked potential localized to the supplementary motor area) and lower sensorimotor beta EEG activity 200-400 ms postperturbation. Significantly greater peak velocities of the center of pressure (i.e., greater postural instability) were also observed during the CMP condition. Our findings provide the first evidence that disruptions to postural control during CMP may be a consequence of insufficient cortical activation relevant for balance (i.e., insufficient cortical N1 responses followed by enhanced beta suppression). We propose that conscious attempts to minimize postural instability through CMP acts as a cognitive dual-task that dampens the sensitivity of the sensorimotor system for future losses of balance.

Maintenance satellite modular docking mechanism design for on orbit servicing to nanosatellites

PurposeAs a result of space debris problem, it is necessary to deorbit uncontrollable satellites or repair them to extend mission duration to avoid sending a new satellite. The purpose of this paper is to develop a docking mechanism that can be easily customized for different missions, providing on-orbit servicing for nanosatellites.Design/methodology/approachThis research outlines a system and mechanism design for the docking phase of on-orbit servicing to nanosatellites. The umbrella-inspired mechanism is designed with utmost simplicity to minimize the likelihood of failure. CAD, structural analyse and mechanism analyse tools are used for designing and analysing the system. To ensure that the design attains the desired durability, numerous iterations are conducted. A three-dimensional (3D)-printed prototype is generated for mechanism verification in laboratory conditions.FindingsThe aimed mechanism is generated successfully. A 3D-printed prototype is assembled to verify the mechanism. Also, an equation for customis the presented design is generated for different mission requirements in the future.Practical implicationsThe usage of the proposed design can help increase the lifespan of satellites.Originality/valueThe primary innovation in this study is the development of a docking mechanism featuring a movable platform to provide servicing for nanosatellites in orbit. The mechanism presented can be displaced without initiating the unfolding process. This provides a customizable coupling distance for different mission requirements. Therefore, the presented mechanism can serve both different types of satellites and more than one satellite on-orbit with a cost-effective design. Also, the presented design can be easily customized to enable adaptation for the different mission requirements in the future.

Two Ways to Control a Pendulum-Type Spherical Robot on a Moving Platform in a Pursuit Problem

Two Ways to Control a Pendulum-Type Spherical Robot on a Moving Platform in a Pursuit Problem

Precise Servo-Control System of a Dual-Axis Positioning Tray Conveying Device for Automatic Transplanting Machine

To address the issues of poor positioning accuracy, low supply efficiency and inadequate adaptability for different tray specifications of the existing seedling tray conveying device, a dual-axis positioning tray conveying device was developed, which can accommodate seedling trays ranging from 21 to 288 holes. A dual-sensor positioning algorithm and variable displacement positioning method were proposed to increase the efficiency, ensuring precise initial positioning and intermittent movements both along the seedling conveyance (X-axis) and platform movement (Y-axis). The system utilizes a precise positioning servo-control system with three-closed-loop controls and a PID algorithm enhanced through simulation to refine seedling positioning accuracy. Experiments with nine different tray specifications were conducted on a step-controlled platform to test suitability, validating the performance of the initial positioning and intermittent transport in both the X and Y directions. On the X-axis, the initial positioning deviation of the seedling tray was up to 1.34 mm and the maximum deviation in the intermission conveying was 0.85 mm. Comparatively, the deviation on the Y-axis was smaller, with the initial positioning deviation up to 0.99 mm and the intermission moving deviation up to 0.98 mm. These results demonstrate that the designed device meets the requirements for precise transport, providing essential technological foundations for seedling tray transport and retrieval steps in fully automated transplanting machines.

Effects of transcranial direct current stimulation combined with Bosu ball training on the injury potential during drop landing in people with chronic ankle instability.

To investigate the effects of transcranial direct current stimulation (tDCS) combined with Bosu ball training on the injury potential during drop landing in people with chronic ankle instability (CAI). A total of 40 participants with CAI were recruited and randomly divided into the tDCS + Bosu and Bosu groups. The people in the tDCS + Bosu group received intervention of tDCS combined with Bosu ball training, and those in the Bosu group received intervention of sham tDCS and Bosu ball training, for 6weeks with three 20-min sessions per week. Before (week0) and after (week7) the intervention, all participants drop-landed on a trap-door device, with their affected limbs on a moveable platform, which could be flipped 24° inward and 15° forward to mimic an ankle inversion condition. The kinematic data were captured using a twelve-camera motion capture system. Two-way ANOVA with repeated measures was used to analyze data. Significant group-by-intervention interactions were detected in the peak ankle inversion angular velocity (p = 0.047, η2 p = 0.118), the time to peak ankle inversion (p = 0.030, η2 p = 0.139), and the plantarflexion angle at the moment of peak ankle inversion (p = 0.014, η2 p = 0.173). Post hoc comparisons showed that compared with week0, the peak ankle inversion angular velocity and the plantarflexion angle at the moment of peak ankle inversion were reduced, the time to peak ankle inversion was advanced in both groups at week7, and the changes were greater in the tDCS + Bosu group compared to the Bosu group. And, a significant intervention main effect was detected in the peak ankle inversion angle in the two groups (p < 0.001, η2 p = 0.337). Compared with the Bosu ball training, the tDCS combined with Bosu ball training was more effective in reducing the injury potential during drop landing in people with CAI.

Reciprocal Inhibition and Coactivation of Ankle Muscles in Low- and High-Velocity Forward and Backward Perturbations

Reciprocal inhibition and coactivation are strategies of the central nervous system used to perform various daily tasks. In automatic postural responses (APR), coactivation is widely investigated in the ankle joint muscles, however reciprocal inhibition, although clear in manipulative motor actions, has not been investigated in the context of APRs. The aim was to identify whether reciprocal inhibition can be observed as a strategy in the recruitment of gastrocnemius Medialis (GM), Soleus (So) and Tibialis Anterior (TA) muscles in low- and high-velocity forward and backward perturbations. We applied two balance perturbations with a low and a high velocity of displacement of the movable platform in forward and backward conditions and we evaluated the magnitude and latency time of TA, GM and So activation latency, measured by electromyography (EMG). In forward perturbations, coactivation of the three muscles was observed, with greater activation amplitude of the GM and lesser amplitude of the So and TA muscles. For backward, the pattern of response observed was activation of the TA muscle, a decrease in the EMG signal, which characterizes reciprocal inhibition of the GM muscle and maintenance of the basal state of the So muscle. This result indicates that backward perturbations are more challenging.

Floating wind-integrated PV system yield analysis considering AHSE dynamics & solar azimuth effects

Floating wind-integrated PV system yield analysis considering AHSE dynamics & solar azimuth effects

Multimodal training protocols on unstable rather than stable surfaces better improve dynamic balance ability in older adults

BackgroundThere has been growing interest in using unstable devices in training protocols. This study aimed to assess the effectiveness of two multimodal exercise interventions (i.e., on stable and unstable surfaces) on dynamic balance control and lower limb strength in older adults.MethodsSixty-two older adults were randomly assigned to two intervention groups (N = 20, stable group; N = 19, unstable group), and to a control group (N = 18). In this single-blinded randomized controlled study, the two intervention groups underwent a 12-week training program twice a week for 45 min, consisting of strength and balance exercises. The stable (ST) group performed the training program over stable surfaces, while the unstable (UNST) group over unstable surfaces. Dynamic balance was assessed by computing the center of pressure (CoP) trajectory while a driven movable platform induced an unexpected perturbation of the base of support. Specifically, we considered the following CoP-related parameters within a 2.5-s temporal window from the beginning of the perturbation: displacement (Area95), mean velocity (Unit Path), anterior–posterior first peak (FP), post perturbation variability (PPV), and maximal oscillations (ΔCoPMax). The dominant quadriceps strength was measured through an isometric maximal voluntary contraction on an instrumented chair.ResultsFour out of five CoP-related parameters (i.e., Area95, Unit Path, ΔCoPMax, and PPV) significantly improved in the UNST group from a minimum of 14.28% (d = 0.44) to a maximum of 52.82% (d = 0.58). The ST group significantly improved only in two (i.e., ΔCoPMax, and PPV) out of five CoP-related parameters with an enhancement of 12.48% (d = 0.68) and 19.10% (d = 1.06). Both intervention groups increased the maximal isometric quadriceps strength (UNST:17.27%, d = 0.69; ST:22.29%, d = 0.98). The control group did not show changes in any of the parameters considered.ConclusionsStable surfaces promoted faster increments of muscular strength. Unstable surfaces were more effective in enhancing dynamic balance efficiency. These findings suggested the employment of multimodal training on unstable rather than stable surfaces to potentially lower the incidence of falls in older adults.Trial registrationNCT 05769361, retrospectively registered 13 March 2023, https://clinicaltrials.gov/study/NCT05769361?lat=45.3661864&lng=11.8209139&locStr=Padova,%20Italy&distance=50&page=11&rank=107.

Configuration design of movable heavy-duty reconfigurable posture adjustment platform with dual motion modes

AbstractThe existing single-mode posture adjustment equipment for solar wing docking is only suitable for a limited number of satellite dimensions; it could not meet the diverse development trends of satellite models. The working range requirements are different when different-sized satellites dock with the solar wing, and the docking process is divided into two stages in this paper. While the DOFs required for the two stages are different, a movable heavy-load reconfigurable redundant posture adjustment platform (RrPAP) with dual motion modes is proposed in this paper. The RrPAP consists of a wheeled mobile platform and a reconfigurable parallel posture adjustment mechanism (PAM). The micro-motion PAM limb types are synthesized, and the comprehensive load-bearing index is proposed to select the mechanism types for heavy-load conditions. A decentralized four-limb six-degree-of-freedom (6-DOF) parallel micro-motion PAM is designed. In the macro-motion stage, for the PAM to still have a defined motion after being released from ground constraints, a serial coupling sub-chain is designed between adjacent limbs to restrict relative movement between them. A type synthesis method for symmetrically coupled mechanisms based on mechanism decoupling and motion distribution is proposed. Four types of symmetrically coupled mechanisms with multi-loop consisting of serial coupling sub-chains are synthesized by using this method. The feasibility of the proposed method is demonstrated through an example using the constraint synthesis method based on screw theory. This work provides a foundation for subsequent refinement and expansion of type synthesis theories and the selection of new types of mechanisms.

Longitudinal Train Dynamics Model for CC203/CC206 Locomotive Simulator

This paper presents train modeling used in a simulator platform for driver training. It was developed for the CC203/CC204 locomotive. The driver will gain experience as in a real locomotive from the perceived platform movements if the movements match real conditions as accurately as possible, including the distance travelled. To this aim, a longitudinal model of the train was developed based on measurement data obtained from the Argo Parahyangan train traveling from Bandung to Jakarta. A second-order linear time invariant model was obtained by a black box identification approach, in which the input and the output of the model are the resultant force (a traction and a slope-friction force) and the train’s position, respectively. While the speed is directly obtained from measurement data, the traction force of the locomotive is predicted using the traction characteristic of the locomotive, train’s measured speed, and latitude time history during a train trip. The model is then validated by running a simulation for one complete trip of the train. In the simulation, the same input as in the model identification is applied and the mileage obtained from simulation result is compared to data of the real train trip with a fitness level of 94.09%.