Boom Rotation Research Articles

Статическое нагружение силового гидропривода звеньев манипулятора лесотранспортной машины в критическом режиме

The safe and effective modes of operation of handling equipment of the manipulator type for the forest complex assume a mandatory horizontal position of the frame of the mobile technological machine. In unfavorable production conditions, a forest transport machine may find itself in a critical situation associated with the rotation of the manipulator's support frame relative to the horizon. Correction of this situation can be provided through the use of outriggers. This paper presents the results of a theoretical study of static loads that are characteristic of hydraulic cylinders of outriggers and other elements of the hydraulic manipulator of a forest transport machine with its various configurations. Technologies for loading, moving and unloading forest cargoes can be carried out using special equipment, subject to certain rules. The safe and effective operation modes of manipulator handling equipment assume a mandatory horizontal position of the support-turntable. In unfavorable production conditions, the wood transport machine may find itself in a critical situation related to the rotation of the support and turning frame of the manipulator relative to the horizon. Correction of such position can be insured by use of outriggers. This paper presents the theoretical study results of the static loads, which are characteristic for the hydraulic cylinder of outrigger and other elements of the hydraulic manipulator of a timber transport machine in its various configurations. Balance equations in generalized coordinates are used to describe the equilibrium conditions of the mechanical system under study, which includes a basic vehicle, outriggers, a boom, a handle with a telescopic extension, a grip device and hydraulic drives that ensure their functioning. The rotation angle of support-turning frame in vertical plane, the boom rotation angle, the handle rotation angle and extension of the telescopic part are selected as generalized coordinates. Analytical expressions are obtained for forces on rods of hydraulic cylinders and the working fluid pressure values in piston cavities of hydraulic cylinders in equilibrium state at different position of manipulator links. Calculations based on the obtained formulas can be used in designing technological modes of operation of timber transport machines for carrying out loading and unloading operations of cargoes with the possibility of bringing the support-turntable into a horizontal position.

Propeller thrust tower crane slewing mechanism model identification

Any study of the dynamics and control of mechanical systems is based on adequate mathematical models that contain the dynamic parameters of the system under study. Their evaluation, in particular for the tower crane boom system, is a particularly relevant scientific and practical problem, the solution of which will provide the basis for further calculations of the optimal modes of movement of the tower crane slewing mechanism. The research aims to determine the dynamic parameters of the installation (moment of inertia of the slewing mechanism J, torque of dry friction forces M0, driving torque coefficient K1) and to plan experimental studies. The experimental method, numerical optimization methods (in particular, the modified Rot-Ring-PSO method), and statistical methods were used to conduct the research. Based on the results of the experiments, the dynamic parameters of the mathematical model of the laboratory installation of the tower crane slewing mechanism with propeller thrust were identified. The criterion that evaluates the identification error of the parameters K1, M0, and J was formed and minimized using the Rot-Ring-PSO algorithm. Plots of the kinematic characteristics of the movement of the boom system in terms of the angle of rotation of the boom and the speed of rotation of the boom were constructed. When processing the experimental data, the dependence of the error values on the supply voltage of the propeller drive was revealed. The error in the boom rotation speed at the drive supply voltage of 90% (compared to the voltage variant of 40%) decreased by almost 15%, and the error in the boom rotation angle at the drive supply voltage of 90% (compared to the supply voltage variant of 40%) decreased by almost 3 times. The regularity has been confirmed that with an increase in the supply voltage, the error value of the system decreases. In the course of processing the experimental studies, the dynamic parameters of the installation were identified: K1=4.80‧10-8 V/(rpm)2, M0=34.519 Nm, J=24.21 kgm2. The obtained results will be used to optimise the plant’s motion modes, and the developed identification algorithm can be used for other similar problems

ТЕОРЕТИЧЕСКОЕ И ЭКСПЕРИМЕНТАЛЬНОЕ ОБОСНОВАНИЕ ИЗМЕНЕНИЯ УСИЛИЙ В ОПОРАХ СТРЕЛОВОГО САМОХОДНОГО КРАНА

In the paper on the basis of the Rostechnadzor report data there is revealed the topicality of the work connected with stability loss of boom self-propelled cranes during the work on weak load-bearing soils. The fulfilled out theoretical investigations of effort distribution in supports depending upon the angle of a boom pitch (boom extension), the angle of boom rotation in a horizontal plane and the weight of the load to be lifted allowed offering a practical realization of measures for boom self-propelled cranes updating at the expense of the introduction of underlying mechanisms allowing not only the assurance of surface horizontal positioning, but the change of soil bearing capacity (supporting surface). 
 For the determination of the effectiveness of the device offered ensuring a table work on weak load-bearing soils there was developed a procedure for the fulfillment of experimental investigations consisting of two stages. At the first stage there were defined efforts in crane supports depending upon a weight of the load to be lifted and sp-acial boom position. At the second stage there was carried out an estimate of crane support subsidence into soil of different state for basic and updated machines. The investigation results are confirmed with confidence probability of 0.95 by Cochran, Student and Fisher criteria. 
 As a result of experimental investigation carrying out there was defined that the application of an updated design allows increasing self-propelled crane stability by 1.41… 2.27 times.

Standardized access options for colorectal surgery with the da Vinci Xi system

Performing colorectal surgery with previous da Vinci system generations presented some limitations that caused uncertainty for surgeons as they began to apply robotic technologies. The da Vinci Xi system is designed to overcome these limitations and to enable multiquadrant colorectal surgery. The design concept of the da Vinci Xi system and the standardized access for colorectal surgery are explained. The da Vinci Xi system applies an overhead boom that maximizes the arm workspace, minimizes interference and makes the port placement universal for standardized access. Colorectal approaches have been validated in numerous cadaver models confirming the reproducibility of the standardized access. Standardized access with astraight-line port placement is possible in all colorectal applications. For right-sided hemicolectomy, atransverse abdominal approach as well as asuprapubic port placement are possible. Utilizing the same principles, left-sided colectomy, sigmoid colectomy and low anterior resections can be performed. Proctocolectomy is enabled through boom rotation and asecond docking. Only minor arm-to-arm interferences occurred and were easily manageable by the bedside assistant. None of the approaches required rearrangement of the patient cart or swapping arms to different port locations. The da Vinci Xi system enables astandardized access for colorectal surgery through auniversal straight-line port placement. Learning this standard principle once enables the surgeon to apply it to all colorectal surgeries and shorten the learning curve as well as minimizing stress for both novices and experienced robotic surgeons learning anew surgical robotic platform.

Similar Operative Outcomes between the da Vinci Xi® and da Vinci Si® Systems in Robotic Gastrectomy for Gastric Cancer.

PurposeThe robotic system for surgery was introduced to gastric cancer surgery in the early 2000s to overcome the shortcomings of laparoscopic surgery. The more recently introduced da Vinci Xi® system offers benefits allowing four-quadrant access, greater range of motion, and easier docking through an overhead boom rotation with laser targeting. We aimed to identify whether the Xi® system provides actual advantages over the Si® system in gastrectomy for gastric cancer by comparing the operative outcomes.Materials and MethodsWe retrospectively reviewed all patients who underwent robotic gastrectomy as treatment for gastric cancer from March 2016 to March 2017. Patients' demographic data, perioperative information, and operative and pathological outcomes were collected and analyzed.ResultsA total of 109 patients were included in the Xi® group and 179 in the Si® group. Demographic characteristics were similar in both groups. The mean operative time was 229.9 minutes in the Xi® group and 223.7 minutes in the Si® group. The mean estimated blood loss was 72.7 mL in the Xi® group and 62.1 mL in the Si® group. No patient in the Xi® group was converted to open or laparoscopy, while 3 patients in the Si® group were converted, 2 to open surgery and 1 to laparoscopy, this difference was not statistically significant. Bowel function was resumed 3 days after surgery, while soft diet was initiated 4 days after surgery.ConclusionsWe found no difference in surgical outcomes after robotic gastrectomy for gastric cancer between the da Vinci Xi® and da Vinci Si® procedures.

Parameters Influencing the Dynamic Behaviour of the Carrying Structure of a Type H Portal Crane

This paper deals with the problems investigating of parameters that influence the dynamic behaviour of the carrying structure of type H portal cranes with high carrying capacities excited by the motion of the crane and the load swing. The introduction of the paper presents the importance of the problem of the dynamics of structures. In accordance with the given problem, dynamic spatial models of the boom and portal of the crane were formed and solved. The main part of the paper presents a modal analysis and determines dynamic responses of the space structure with the application of the finite element method and direct integration. The influence of changes in speed and acceleration on the dynamic response of the structure was analysed. The influence of the change of boom rotation angle on the dynamic response of the structure was also analysed. The investigation results provide significant bases and conclusions for designing portal cranes and continuation of research in this field.

Simulation-assisted teaching of graduate students in transport: A case study of the application of acausal freeware JModelica.org to solution of Sakawa’s open-loop optimal control problem for payload motion during crane boom rotation

The present article is focused on the improvement of the quality of engineering education of graduate students with a major in transport and mechanical engineering through the derivation of a numerical solution of the optimal control problem for payload swaying during crane boom slewing, formulated by Sakawa et al. For the first time, a numerical solution of Sakawa’s problem has been derived with an application of JModelica.org freeware. The fundamental difference between this solution and Sakawa’s is the imposition of a restrictive constraint on the allowable value of payload swaying during boom-driven payload motion. The solution derived by the authors for Sakawa’s problem takes exact account of the restrictive constraints on the phase variables in contrast to Sakawa’s model, where the restriction constraints on the phase variables have been approximated. The complex of authors-proposed computational algorithms was implemented with JModelica.org. The proposed open-code algorithms derive numerical data and computational plots, which enhance and expand students’ knowledge about the dynamics of guided boom-driven payload swaying during rotary crane boom slewing.

Моделирование рабочих процессов энергосберегающего гидропривода технологического оборудования лесотранспортной машины

Workflow mechanisms of forestry cranes tower rotation are accompanied by large dynamic loads that cause sudden changes in fluid pressure in balancing and braking modes. When the rotary column stops at different positions damping of pressure of the working fluid vibration occurs due to its overflow from one chamber to another through an orifice, wherein the hydraulic energy is transformed into heat one, resulting in overheating and energy loss of fluid. Efficient are energy-saving hydropneumatic drives of column of the manipulator which are able to recover energy during transient conditions and to return some of the energy back into the system. For hydraulic manipulators with four paired hydraulic cylinders of rotation mechanism of the column one pair of cylinders is proposed to be replaced by pneumatic cylinders connected to a rotary column through the gear and toothed rack that allows you to transfer it into recovery mode of energy. A mathematical model of the boom rotation of the manipulator is developed; equations for a hydro pneumatic system recovery are made. In the model three mechanical processes are considered: the rotational movement of the column about the vertical axis of the manipulator, the forward movement of the plunger along the axis of the damper, and sway of the load relative to the attachment point on the manipulator arm. To solve the system of differential equations, computer program for the simulation of hydraulic manipulator equipped with a hydraulic damper is composed. The dependence of the restoring force of the displacement of the toothed rack is get. In the vicinity of the equilibrium position, this dependence is nearly linear over a wide range of rack movement: from about 50 to 180 mm. With significant turns of the column volume of one of the chambers of the air cylinder approaches zero value, whereby the restoring force of the module increases significantly, which helps braking of the column in the final step of rotation and influences the process of energy accumulation.

Trajectory Optimization Method for Follow-Up Control of Concrete Pump Truck

The follow-up control of concrete pump truck is in order to solve the problem that whole boom follows the movement of boom end under the artificial traction. Focus on real-time detection of boom end azimuth change and inverse kinematic problems of redundant boom system, two-axis gravitational accelerometer is used to detect azimuthal variation of boom end, and the best motion trajectory of boom is determined by solving constrained nonlinear optimization function which takes minimum displacement distance of barycentre for the whole boom as the optimization goal. At last, relative azimuth and translation of boom end, rotation of boom are solved together to make translation and rotation of boom being synchronization. In this way to ensure whole boom follows the artificial traction in theory. In order to verify the discussion above, matlab is used to simulate several different working conditions for the follow-up control of boom.

Design Optimisation for the Vertical Suspension of a Crop Sprayer Boom

The dynamics of a vertical suspension for a 39 m wide boom on a John Deere crop sprayer was optimised. The optimisation was based on a mathematical model of the suspension with an existing non-linear Koni® damper characteristic. During the optimisation, several tracks, which are based on power spectral densities of measurements in different field conditions, are applied to the suspension. The objective function to be minimised is the standard deviation of the absolute boom rotation around the horizontal axis while applying the tracks. As the model is simple but accurate, computation time is small such that many different field situations can be imposed during optimisation. By playing with the distance to the rotation point of the damper and selection of the appropriate damping value, the optimum could be realised.

Control of Rotary Crane Based on Discretizing Method.

Rotary crane control based on several discretizing methods has been proposed in this paper. The motion of the crane load is described by a discrete time system by assuming zero order and trapezoidal hold for the boom rotation. The stabilization of the load boils down to a finite settling time problem with constraints. This problem is reduced to solving a 6-th order equation for five step case, and an optimizing problem with constraints for more step case. Various simulation results have been given to show the effectiveness of the proposed method.

SWAY CONTROL OF ROTARY CRANE BASED ON DISCRETIZING METHOD

Rotary crane control based on several discretizing methods has been proposed in this paper. The motion of the crane load is described by a discrete time system by assuming zero order and trapezoidal hold for the boom rotation. The stabilization of the load boils down to a finite settling time problem with constraints. This problem is reduced to solving a 6-th order equation for five step case, and an optimizing problem with constraints for more step case. Various experiment results have been given to show the effectiveness of the proposed method.