Validation of an analytical method for payload estimation in excavators

Accurate estimation of the body center of mass (COM) location has important clinical ramifications in locomotion associated with daily activities of living (ADL). This paper compared two computational estimation methods of COM using an accelerometric measurement and a VICON motion analysis system measurement (established or golden standard), respectively. A convenient sample of four healthy subjects participated. The body COM was measured when the subjects walked on the 6-m long walkway at their self-selected speed for 5 trials. VICON and accelerometer COM data signals were computed by VICON Polygon and trapezoidal double integration methods, respectively and compared to determine the concurrent validity of our COM estimation method. Correlation statistics showed excellent relationship between the two methods (r =0.87, P< 0.05), reflecting an acceptable validity. Our results suggest that the COM estimation using the accelerometer method is as accurate as the conventional method and provide clinical insights when designing a portable and inexpensive COM measurement tool for locomotion evaluation.

Vertical body position during swimming is assumed to closely affect drag. It is consequently associated with swimming velocity; however, the association between swimming velocity and vertical body position has not yet been sufficiently established. Here, we aimed to clarify how vertical body position increases with front crawl velocity and whether there are inter-individual differences in velocity effect. Eleven college-level male swimmers performed a 15 m front crawl with sustained forced maximal inspiration at various swimming velocities. The body’s centre of mass (CoM) was estimated from individual digital human models with inertial parameters using inverse kinematics. The horizontal CoM velocity and vertical CoM position from the water surface were averaged for one stroke cycle as respective indexes of swimming velocity and vertical body position. Linear mixed-effects model analysis revealed that there is a positive trend between swimming velocity and vertical CoM position during front crawl across the participants. These results indicate that swimming velocity is associated with vertical body position during front crawl. Additionally, the linear mixed-effects model with random intercepts and slopes was a better fit than that with only random intercepts, indicating that there are inter-individual differences in the rate of increase in vertical body position against swimming velocity.

A spectrophotometric method for estimation of titanium alkoxide, a catalytically active form of titanium in oligomer/ polymers

The objective of this study was to develop and validate a reliable, efficient, and robust RP-HPLC method for the simultaneous estimation of Empagliflozin and Metformin in pharmaceutical dosage forms. A high-performance liquid chromatography (HPLC) method was developed using a mobile phase consisting of methanol and acetonitrile (75:25 v/v), with an X-Bridge C18 column (4.6 × 150 mm, 5.0 µm) for the separation of both drugs. The chromatographic separation was performed at a flow rate of 1 mL/min and the detection was carried out at 260 nm. The column temperature was maintained at 35ºC, and the injection volume was 10 µL. The total run time was 14 minutes, allowing for efficient separation of Empagliflozin and Metformin within a short analysis time. The method was validated in accordance with ICH guidelines, covering parameters such as accuracy, precision, linearity, specificity, and robustness. The results demonstrated that the method is accurate, precise, and reproducible, with good resolution between the two drugs. The method exhibited excellent linearity with correlation coefficients greater than 0.999 for both Empagliflozin and Metformin. The limit of detection (LOD) and limit of quantification (LOQ) were found to be suitable for routine pharmaceutical analysis. This validated RP-HPLC method can be effectively employed for the quality control of Empagliflozin and Metformin combination products in the pharmaceutical industry, ensuring the integrity and safety of the drug formulation.

In traditional physical therapy, balance evaluation is performed by the physical therapist (PT) intermittently during clinic visits, which is subjective, inconvenient, and time-consuming. In this paper, we use sensors and deep learning to propose an automated balance evaluation system for home and clinical use. First, we propose a deep learning-based model to estimate the subject's Center of Mass (CoM) position using a depth camera, which outperforms other CoM estimation methods with high accuracy and ease of use. Then we propose a balance evaluation system to evaluate the subject's dynamic balance in a Gait Initiation (GI) task. The subject's CoM position is estimated by the proposed CoM estimation model and the Center of Pressure (CoP) position is measured by a Wii balance board. The CoP-CoM trajectory during the GI task is used to assess and quantify the patient's dynamic balance control. Using data collected from both healthy subjects and patients with Parkinson's Disease, the proposed balance evaluation model is able to quantify the subject's balance level which is consistent with the human PT's assessments in traditional balance evaluation tests. The proposed balance evaluation system can be used as a portable and low-cost tool for on-demand balance evaluation.

When model-based controllers are used for carrying out precise tasks, the estimation of model parameters is key for a better trajectory tracking performance. We consider the scenario of a free-flying space robot with limited actuation that has grasped an object of unknown properties. The inertial parameters - mass, centre of mass and the inertia tensor - of the robot-object system are to be determined. In our previous works, we used a parameter estimation algorithm where truncated Fourier series were used to represent both the reference excitation trajectory and the executed one. That algorithm is the focus of this paper, along with a study of the factors that could contribute to a loss of accuracy in the obtained estimates. Simulation results with the Space CoBot free-flyer robot are used to find the causes of the latter: first, a modified version of the minimum condition number criterion is used to generate feasible excitatory trajectories. The results are compared with those given by the maximum information criterion to check for better excitation. Next, an appropriate number of harmonics has to be found for the Fourier series, which will be used to fit the measured data. This is done autonomously, based on the least squares residual. Finally, the relation between input saturation while executing the excitation trajectory and the errors in the resulting parameter estimates is studied.

Accurate knowledge of geometric and inertia parameters are a necessity for precise and robust control of aerial vehicles. We propose a novel filter that is able to fuse motor speed, inertia, and pose measurements to estimate the vehicle’s key dynamic properties online. The presented framework is able to estimate the multirotor’s moment of inertia, mass, center of mass and each sensor module’s relative position. Obtaining these estimates in-flight allow the multirotor to be precisely controlled even during tasks such as load transportation or after configuration changes on scene. We provide a nonlinear observability analysis, proving that the presented model is locally weakly observable. Experimental results validate the proposed approach, showing the ability to estimate the dynamic properties accurately and demonstrate its capability to do so even while additional loads are added. The framework is flexible and can easily be adapted to a wide range of applications, including self-calibration, object grasping, and single robot or multi-robot payload transportation.

Parameter estimation of a three-axis spacecraft simulator using recursive least-squares approach with tracking differentiator and Extended Kalman Filter

Succinylcholine chloride injection USP is a sterile, non-pyrogenic solution to be used as a short-acting, depolarizing, skeletal muscle relaxant . The injection is administered as IM or IV use. Succinylcholine chloride, USP is chemically designated C 14 H 30 N 2 O 4 and its molecular weight is 290.399. Succinylcholine chloride has three known impurities: (1) Doublet peak, (2) Succinic acid and (3) Succinylmonocholine chloride. Out of these impurities, succinic acid and succinylmonocholine chloride are degradation impurities, whereas doublet peak is process related impurity. These impurities are controlled in succinylcholine chloride injection. Hence, an analytical method for simultaneous estimation of succinic acid and succinylmonocholine chloride in succinylcholine chloride injection is developed and validated.In this method, succinic acid and succinylmonocholine chloride were found to be specific, linear and robust. The method is also stability indicating as evidenced by forced degradation studies. Hence, this method can be used for routine analysis. Keywords: Succinylcholine chloride injection, degradation products, HPLC Cite this Article Subrahmanya Bhat K,Puranik SB, Mahabaleshwara K. HPLC method development and validation for simultaneous estimation of succinic acid and succinylmonocholine in succinylcholine chloride injection. Research & Reviews: A Journal of Drug Formulation, Development and Production . 2015; 2(3): 52–60p.

Recently, the increase of burden to operators and lack of skilled operators are the issue in the work of the hydraulic excavator. These problems are expected to be improved by autonomous control. In this paper, we present experimental results of hydraulic excavators using model predictive control (MPC) which incorporates servo mechanism. MPC optimizes digging operations by the optimal control input which is calculated by predicting the future states and satisfying the constraints. However, it is difficult for MPC to cope with the reaction force from soil when a hydraulic excavator performs excavation. Servo mechanism suppresses the influence of the constant disturbance using the error integration. However, the bucket tip deviates from a specified shape by the sudden change of the disturbance. We can expect that the tracking performance is improved by combining MPC and servo mechanism. Path-tracking controls of the bucket tip are performed using the optimal control input. We apply the proposed method to the Komatsu- made micro hydraulic excavator PC01 by experiments. We show the effectiveness of the proposed method through the experiment of digging soil by comparing servo mechanism and pure MPC with the proposed method.

&lt;sec&gt;The Taiji program is a space mission designed to detect low-frequency gravitational waves. The mission's success hinges on the precise operation of its core payloads, particularly the inertial sensors, which are responsible for measuring the residual acceleration noise of the test masses. The duration of a space-based gravitational wave detection mission is 3 to 5 years. During this period, the shift in the satellite’s center of mass due to propellant consumption and other factors, as well as the drift in the scale factors caused by electronic component aging, will gradually degrade the accuracy of inertial sensor data. Therefore, it is necessary to regularly perform in-orbit calibration of inertial sensor parameters.&lt;/sec&gt;&lt;sec&gt;In this work, we develop a calibration scheme, which actively applies controlled satellite oscillations and is tailored according to the installation layout of the inertial sensors in the Taiji program and the noise models. For the calibration of scale factors, high-precision star sensors are used to measure the satellite attitude signal, which is then combined with the driving voltage data from inertial sensors. By using the linear relationship between these signals, the scale factors are estimated using an extended Kalman Filter. For the calibration of center of mass (CoM) offsets, the calibrated scale factors are utilized, along with the driving voltage data from the front-end electronics of inertial sensors, to derive the test mass's angular acceleration, linear acceleration, and angular velocity. These parameters are then used to complete the CoM offset calibration according to the dynamic equation.&lt;/sec&gt;&lt;sec&gt;The feasibility of the proposed calibration scheme is validated through a simulation experiment. The results demonstrate that the scale factors of the three axes can be calibrated to relative accuracies of 33 ppm, 27 ppm, and 173 ppm , respectively, meeting the requirement within 300 ppm. The CoM deviation are calibrated with accuracies of &lt;inline-formula&gt;&lt;tex-math id="M2"&gt;\begin{document}$ {\delta }_{{\boldsymbol{r}}_{1}}= $\end{document}&lt;/tex-math&gt;&lt;/inline-formula&gt;[15 μm, 31 μm, 34 μm], &lt;inline-formula&gt;&lt;tex-math id="M4"&gt;\begin{document}$ {\delta }_{{\boldsymbol{r}}_{2}}= $\end{document}&lt;/tex-math&gt;&lt;/inline-formula&gt;[5 μm, 15 μm, 13 μm], satisfying the 75 μm threshold. These results confirm that the proposed scheme can effectively maintain the inertial sensors’ performance within the required accuracy range.&lt;/sec&gt;&lt;sec&gt;All in all, the calibration scheme developed in this study is crucial for maintaining the high performance of inertial sensors in the Taiji program. By achieving the precise calibration of the scale factors and deviation of center of mass within the required accuracy ranges, the scheme ensures the reliability of inertial sensor data, thereby significantly enhancing the sensitivity of space-based gravitational wave detection, which paves the way for groundbreaking discoveries in astrophysics and cosmology.&lt;/sec&gt;

Human balance in stance is usually defined as the preservation of the vertical projection of the center of mass (COM) on the support area formed by the feet. Under microgravity conditions, the control of equilibrium seems to be no longer required. However, several reports indicate preservation of COM control in tasks such as arm or leg raising, tiptoe standing, or trunk bending. It is still unclear whether COM control is also maintained in complex multijoint movements during short term exposure to microgravity. In the current study, the dynamics of equilibrium control were studied in four subjects performing two series of seven whole-body lifting movements under microgravity during parabolic flights. The aims of the study were to examine whether the trajectory of horizontal COM motion during lifting movements changes in short-term exposure to microgravity and whether there is any sign of recovery after several lifting movements. It was found that, compared with control movements under normal gravity, the horizontal position of the COM was shifted backward during the entire lifting movement in all subjects. In the second series of lifting movements under microgravity, a partial recovery of the COM trajectory toward the normal gravity situation was found. Under microgravity, angles of the ankle, knee, hip, and lumbar joints differed significantly from the angles found under normal gravity. Recovery of joint angular trajectories in the second series of lifting movements mainly occurred for those angles that could contribute to a reduction of the backward COM shift. It is to be pointed out that COM control under microgravity is not redundant but functional. Persisting COM control under microgravity may be required for pure mechanical reasons, since rotational movements of the body are dependent on adequate control of the COM position with respect to external forces. It is shown that, from a mechanical perspective, subjects can benefit from a backward displacement of the COM in the downward as well as the upward phase of the lifting movement under microgravity.

Combinatorial treatment utilizing a nucleoside analogue gemcitabine (GEM), with a characteristic pentacyclic triterpenoid betulinic acid (BET), has exhibited empowering adequacy in the therapy of cancer. It lessens the advancement of collagen and upgrades the saturation of tumour medicines. With the advancement in nanotechnology, the co-loaded formulation urges for a validated method of estimation. The purposed work entails a robust, simple, and economical analytical method for the simultaneous estimation of GEM and BET through RP-HPLC. Orthophosphoric acid (0.1%)-acetonitrile was considered as the mobile phase for the detection of GEM and BET at 248nm and 210nm with retention times of 5min and 13min, respectively. The method was further validated as per the regulatory guidelines with all the parameters found within the limit. The developed method with adequate resolution and quantification was found to be linear, accurate, precise, robust, and stable with an intra- and inter-day variability of less than 2%. The method was found specific for GEM and BET with no matrix interference of drug-spiked FBS samples. To demonstrate the applicability of the developed method, a nano-formulation containing GEM and BET was prepared and assessed for various parameters including encapsulation efficiency, loading efficiency, drug release, and drug stability. The method developed can be a possible tool for the simultaneous quantification of GEM-BET in analytical and biological samples.

Fuzzy Inference System for Congestion Index Estimation Based on Speed Probability Distributions

This book describes analytical models and estimation methods to enhance performance estimation of pipelined multiprocessor systems-on-chip (MPSoCs). A framework is introduced for both design-time and run-time optimizations. For design space exploration, several algorithms are presented to minimize the area footprint of a pipelined MPSoC under a latency or a throughput constraint. A novel adaptive pipelined MPSoC architecture is described, where idle processors are transitioned into low-power states at run-time to reduce energy consumption. Multi-mode pipelined MPSoCs are introduced, where multiple pipelined MPSoCs optimized separately are merged into a single pipelined MPSoC, enabling further reduction of the area footprint by sharing the processors and communication buffers. Readers will benefit from the authors combined use of analytical models, estimation methods and exploration algorithms and will be enabled to explore billions of design points in a few minutes.