Electric Cylinder Research Articles

Trajectory planning and control strategy optimization design of double electric cylinder erecting device

The transition of the rocket from a horizontal to an erect state before its launch on the offshore platform is a crucial stage. Compared with erecting the rocket on the ground, higher servo control and synchronization accuracy are required for erecting it on the offshore platform. Most rocket erecting devices on offshore platforms rely on hydraulic drive systems, posing challenges due to their lower servo control accuracy and difficulties in achieving high-precision synchronization. The erecting process, trajectory planning, control system, and control strategies of rockets driven by a double electric cylinder erecting device are studied, aiming at the requirement of erecting rocket devices on offshore platforms. This paper commences by establishing the kinematic model of erecting the rocket with a double electric cylinder erecting device. It delves into the process and trajectory of the erection rocket with a double electric cylinder erecting device. Subsequently, the focus shifts toward designing the control system, while inclination and angular velocity sensors monitor the erection process. Finally, designing and demonstrating control strategies for a double electric cylinder erecting device, three different control strategies, master control, master-slave control, and cross-coupling control, are analyzed, and the cross-coupling control strategy is selected as the control strategy of the double electric cylinder offshore platform rocket erecting device.

A state-space heating and cooling model for thermal stratification in horizontally configured electric hot water storage cylinders

Domestic water heating significantly impacts global energy demand, with electric hot water storage devices notably contributing to grid load. Efficient management of these widespread devices is contingent on a deep understanding of the internal thermal stratification occurring naturally during heating and cooling phases. While extensive research exists for vertical water heaters, horizontal heaters, more challenging to model, have been comparatively overlooked in scholarly research. This paper introduces a state-space model developed using measured datasets, aimed at accurately describing temperature distributions inside a horizontally-configured electric hot water storage cylinder during heating, thermal diffusion, and cooling stages. The model’s effectiveness was validated through various evaluation metrics and separate, unseen evaluation datasets. It achieved an accuracy of 90.6% for the dimensionless stratification factor, 94.6% for the dimensionless exergy number, and reported Root Mean Square Errors (RMSEs) of 150kJ for energy, 11kJ for exergy, and 0.8°C for temperature.

Impedance control for a Stewart‐structure‐based wheel‐legged robotic system in wheel motion

SummaryAn impedance control scheme is proposed for a Stewart‐structure‐based wheel‐legged robotic system to strengthen the dynamic attitude adjustment stability in wheel motion. The wheel‐leg, which is driven by electrical cylinders in the Stewart structure, is analyzed in kinematics and dynamics. The rotation in the axial direction of every electric cylinder is calculated to improve the accuracy of the kinematic model. To fulfill the impedance demands, a passive structure with 6 degrees of freedom (DOF) is modeled. The mass of the mechanism has a coupling effect on the impedance model for each DOF, which is a nonlinear function. As motion decoupling in the workspace has been completed for the Stewart structure, an impedance control strategy with inner‐loop position tracking is employed. An extended state observer (ESO) is designed to estimate the disturbances arising from the nonlinear coupling effects. Based on the ESO observation outputs, an active disturbance rejection control that explicitly handles the workspace limit is designed with guaranteed practical stability. By reducing force interaction and body vibration, the wheel‐legged robotic system keeps wheel motion stability on uneven roads. Multiple comparative experimental results are presented to validate the stability and effectiveness of the proposed method.

Study of the electromagnetic system of holding the mine in the barrel channel of the gas detonation mortar

The paper presents the results of the study of the electromagnetic system of holding the mine in the bore of the gas detonation mortar. To reduce the time from the detection of the target to its destruction, the use of a gas detonation mortar with a semi-automatic guidance system in the direct line of sight of the target is proposed. This type of mortar will reduce the total time of hitting the target to 2-3 minutes. An analysis of the influence of the magnetic holding of the mine on the operation of the gas detonation mortar was carried out. Holding the mine in the bore during the formation of the gaseous propellant charge allows you to fix the volume of the charge. The electromagnetic mine holding system consists of an electromagnetic coil, a magnetic circuit, a DC source with a commutator. The switch on of the electromagnetic system is carried out immediately before the shot to reduce the heating of the coil. The mine holding force was calculated, on the basis of which the parameters of the mine holding electromagnetic system were substantiated. Based on the results of experimental studies, the dependence of the holding force of the mine on the power supply current of the electromagnetic system was determined. The developed dynamometric measurement system consisted of a piezoelectric force meter with a spring, an electric cylinder and a cable clutch. The pressure when the mine detaches from the electromagnet in the barrel of the gas detonation mortar is estimated. It was found that the power consumed by the electromagnetic system is about 15 W, and with holding forces of 930-980 N, mine extraction will begin at the overpressure of the compressed gas charge, equal to 0.15-0.2 MPa.

Design of Batch Automatic Testing System Based on Electric Cylinder

With the increasing demand for weapons and equipment, more manpower and material resources need to be invested to complete the batch production of weapons and equipment models. In order to save production costs and improve the efficiency of batch production, a batch automatic test system based on electric cylinders is developed. The system is divided into an automatic test system and a batch tangent system. They are respectively used to achieve product testing and batch product line change control to reduce human intervention and improve the accuracy and efficiency of product testing.

Modeling and invariably horizontal control for the parallel mobile rescue robot based on PSO-CPG algorithm

AbstractA walking robot consisting of double Stewarts parallel legs was designed by our research team in the past time, which was mainly used for the transportation of the wounded after the disaster. In order to promote stability of control locomotion and ensure invariably horizontal state of the robot platform in the process of motion, the central pattern generator (CPG) based on particle swarm optimization (PSO) is presented to optimize the kinematic model. The purpose of optimization is to solve the hysteresis problem of displacement variation among the electric cylinders. Moreover, the dynamic model of the robot is established, which can provide mechanical basis for the feedback of control signal and make the robot move stably. The simulation results show that the displacement hysteresis problem of the electric cylinders is solved well. Meanwhile, compared with simulation results based on GA-CPG method, it is demonstrated that the robot motion planned using PSO-CPG method has better motion stability and can avoid the impact of legs landing during the transition phase of the motion cycle. The experimental results show that the platform on the robot can maintain an invariably horizontal state, and the locomotion is more stable. It verifies the feasibility of PSO-CPG model and the correctness of the dynamic model of the parallel mobile rescue robot.

Design and development of high precision four roll CNC roll bending machine and automatic control model

In recent years, advancements in industries such as aerospace, military weaponry, automobiles, locomotives, and shipbuilding have led to a surge in the demand for bent and rolled components, along with increasingly stringent requirements for rolling precision. However, the traditional hydraulic cylinder feeding solution has hindered further enhancements in the accuracy of rolled profile contours. Additionally, owing to variations in profile specifications, material properties, and an assortment of random factors during the forming process, the applicability of existing forming formulas remains limited, rendering them suitable only for profile processing under specific circumstances. To address these challenges, servo electric cylinders have been introduced as a replacement for traditional hydraulic cylinders, and the mechanical structure of a four-roll bending machine has been re-engineered. This innovation has demonstrated the feasibility of employing servo electric cylinders in four-roll CNC bending machines for profile bending, resulting in higher control precision and faster response times, ultimately providing a comprehensive design solution for four-roll CNC bending machines. In response to the limited universality of existing forming formulas, the actual R (profile forming curvature) and d (servo electric cylinder feed) values from the four-roll CNC bending machine have been utilized, and curve fitting methods have been implemented as the foundation for the automatic control model. This approach offers a high degree of universality, making it suitable for a wide range of applications. Moreover, as the number of trials increased, forming precision progressively improved.

Design and Research of Missile launcher Drive System for Anti-aircraft Gun and Missile Weapon System

Aiming at the problems of large size and weight of electric cylinder, low efficiency and large pressure fluctuation of centralized hydraulic drive system, a drive system of anti-aircraft gun and missile weapon system based on electro-hydrostatic actuator is designed. The working principle of the hydraulic system of electro-hydrostatic actuator is discussed, its components are selected and designed, the micro cartridge hydraulic control check valve is designed and the electro-hydrostatic actuator is analyzed and integrated structure is designed;The simulation model is established by AMEsim software. The simulation results show that the electro-hydrostatic actuator can move the missile driving device to the highest position within 2s, meet the working requirements, and have certain guiding significance for the research and development of missile launcher driving.

A Prediction Method of Ship Motion Based on LSTM Neural Network with Variable Step-Variable Sampling Frequency Characteristics

In active heave compensation, in order to realize the smooth control of the heave compensation platform, it is necessary to use the ship motion measurement system to accurately obtain the ship displacement signal, invert the ship displacement signal, and then control the expansion and contraction of the electric cylinder so that the compensation platform remains horizontal. The ship displacement measurement system generally adopts the second integral of the acceleration sensor to obtain the ship displacement signal. During the acquisition process of the ship displacement signal, the quadratic integration process of the acceleration, and the communication process of the output control command, there is a processing lag which makes the error accumulate, resulting in a delay in the measurement of the ship motion. In order to collect the ship motion more accurately and control the heave compensation platform more precisely, this paper proposes a ship motion prediction method based on a variable step-variable sampling frequency characteristic LSTM (Long Short-Term Memory) neural network. First, we use the autocorrelation function algorithm to calculate the inherent delay of the lag in the process of signal acquisition by the measurement system. Secondly, the LSTM neural network is used to predict the inherent delay step of the lagging ship displacement signal. During the prediction process, it is found that the difference in the sampling frequency of the displacement signal will lead to a change in the step of the inherent delay—experiment in the laboratory to verify. By controlling the motion platform to simulate the motion of the ship and using the ship motion measurement system and the laser sensor system to measure the displacement signal of the motion platform synchronously, it is verified that the ship motion measurement system does have an inherent delay. Thirdly, on a sailing ship, ship displacement signals are collected by setting multiple sets of ship motion measurement systems. Finally, multiple sets of sampling frequency and multiple steps are set, and the ship motion is predicted based on the variable step-variable sampling frequency LSTM neural network. It is verified that the prediction accuracy is related to the sampling frequency of the signal collector and the prediction step of the LSTM neural network, which improves the prediction accuracy of the model and the timeliness of ship motion acquisition.

Assessing the energy storage potential of electric hot water cylinders with stochastic model-based control

ABSTRACT As electric hot water cylinders (HWCs) have a large capacity for thermal storage, they are well-suited for Demand Side Management (DSM). This paper compares different methods of HWC temperature control and presents a methodology to assess the amount of thermal storage available in HWCs for demand side management based on use behaviour in different household types. Simple stochastic methods for domestic hot water (DHW) demand prediction were employed to design a smart controller that produced lower rates of unmet DHW demand and higher available storage than setpoint and ripple controllers. The average storage available for DSM from the use of this smart controller is predicted to be between 3.63 and 7.20 kWh per household. These results indicate the use of HWCs for thermal storage is a low-cost viable option for peak-shaving of power system load and could decrease power system greenhouse gas (GHG) emissions in countries such as Aotearoa New Zealand, where GHG-emitting electricity generation is primarily used to meet peak loads.

P‐2.32: Six‐degree‐of‐freedom Platform Motion Anomaly Prediction Technology Based on Binocular Vision

Binocular stereo vision is based on the principle of parallax and uses imaging equipment to obtain two images of the measured object from different positions, and obtains the three-dimensional geometric information of the object by calculating the position deviation between the corresponding points of the image. As an important execution component of the six-degree-of-freedom platform in the flight simulator, the electric cylinder can undertake the important task of dynamic simulation, and its abnormal working state directly affects the training effect and life safety of the flight simulator users. In this paper, the electric cylinder position pose is obtained by the three-dimensional point cloud method, and the improved active learning anomaly detection algorithm is proposed to predict the electric cylinder position posture, so as to determine whether the platform electric cylinder fails.

Experimental Research on Integrated Disassembly Equipment of Super Large Offshore Oilfield Facilities

Based on the key module-lifting arm system, based on the principle of similarity and the hydrodynamic experimental method of a multi-dimension vibration test platform, an experimental platform for dismantling equipment is designed and built. Subsequently, the motion control model of the six-degrees-of-freedom platform is established. The three-ring control model of a servo electric cylinder is established, and the active heave compensation control of a servo electric cylinder is realized by combining position control theory. Based on the co-simulation of ADAMS and Simulink, the co-simulation system of the integrated dismantling equipment experimental platform is designed and built, and the simulation system is tested and verified. Finally, simulation and experimental verification are carried out based on the experimental platform and co-simulation system. The results show that the heave compensation rate reaches 58.3% in third-class sea conditions, 61.2% in fourth-class sea conditions, and 62.4% in fifth-class sea conditions. The integrated dismantling scheme of super large offshore oilfield facilities is feasible but, in order to ensure the safety and reliability of the operation, a heave compensation system needs to be added. The error between the simulation results and the experimental results is about 15%. Based on the analysis of external interference factors in the experiment, the error results are within a reasonable range, which proves that the experimental platform, the co-simulation system of the experimental platform, and the heave compensation strategy are accurate and effective. This study, for the first time in China, provides an effective experimental platform and co-simulation platform for the design and optimization of the integrated dismantling equipment of super large offshore oilfield facilities and lays a good research foundation for the construction and engineering demonstration of subsequent equipment.

An Offshore Self-Stabilized System Based on Motion Prediction and Compensation Control

The swaying motion of ships can always be generated due to the influence of complex sea conditions. A novel offshore Self-Stabilized system based on motion prediction and compensation control was studied. Firstly, an autoregressive model of ship motion exposed to various sea conditions was established, and the parameters of the model were initialized and updated by offline and online learning historical data. Using the autoregressive model with the acquired parameters, the prediction of the ship’s motion was achieved. Then, a Self-Stabilized system platform composed of six electric cylinders in parallel was designed, and the corresponding inverse kinematics were established. The corresponding controller using the result of motion prediction as the input was also proposed to counteract the extra motion variables of the ship. Various experiments, by simulating different sea conditions, can be carried out. The results show that the average error of the motion prediction was less than 1%. The maximum error of the self-stabilizing control was 1.6°, and the average error was stable within 0.7°. The Self-Stabilized system was able to effectively compensate for the rocking motion of ships affected by waves, which was of great significance for improving the maritime safety guarantee and the intelligent level of shipborne equipment.

Design of a container grabbing and lifting mechanism for equipping a robotic wheeled chassis

This article presents the results of designing a mechanism for grabbing, lifting and holding a container with which it is supposed to equip a robotic wheeled chassis with an apple harvesting module in an industrial garden. The technical solutions used in agricultural engineering for lifting and holding operations of various types of loads weighing from 300 kg were analyzed, their design and technical features were considered. As a result of the analysis, based on the criteria of compactness and metal consumption, the most preferred variant of the lifting mechanism was selected - a parallelogram lifting mechanism driven by electric cylinders. In order to fulfill the conditions of structural strength of the mechanism for gripping and lifting the container, a strength calculation of the structure was carried out, and also the necessary characteristics of the electric cylinder for the mechanism for lifting the container and the paws for the mechanism for lifting the paws were determined. The main load in the structure is carried by the upper horizontal guides, vertical racks and lower grips. As a result of the analysis, zones of maximum stress and strain concentration were established. The loading of the lower gripper parts occurs with a force directed vertically downward with a force of 1750 H. The highest voltage was about 169 MPa, which ensures sufficient strength of the part with a margin of 3 times, the maximum movements of the guides are 1.6 mm.

Novel compressive sensing computing model used for analyzing electromagnetic scattering characteristics of three-dimensional electrically large objects

The method of moments is one of the most effective algorithms for solving electromagnetic scattering problems. However, the high computational complexity limits its application to electrically large problems. As an improved algorithm, the compressive sensing-based method of moments introduces the compressive sensing technique into the algorithmic structure, which avoids the inverse of the matrix equation and improves the computational efficiency. Using the underdetermined equation-based calculation model, this scheme is utilized to efficiently analyze the bistatic scattering of the objects. In this technique, the extracted few rows from the impedance matrix are used to construct the measurement matrix. Nevertheless, the results are unstable due to the random extraction utilized to build the measurement matrix. Furthermore, it is challenging task to provide an appropriate sparse basis for the induced currents of three-dimensional objects discretized by the Rao-Wilton-Glisson basis functions. To address the aforementioned issues, a novel compressive sensing calculation model that enhances measurement matrix building, sparse basis construction, and recovery is provided in this paper. First, several rows of the impedance matrix are uniformly extracted to produce consistent computation results, which is opposed to the randomly constructed measurement matrix in the conventional technique. The number of rows to be extracted is typically set to be 3–5 times the number of basis functions for high accuracy. Then, the characteristic basis functions based on the Foldy-Lax equation are employed to construct the sparse basis. Considering the prior knowledge that the lower order characteristic basis functions are dominant, the columns of the recovery matrix corresponding to some low-order characteristic functions are determined in advance as the columns that will be identified by the recovery algorithm, thus simplifying the recovery algorithm to a least-squares operation. Obviously, the matrix equation is reduced to an overdetermined equation instead of the underdetermined equation since only a few low-order basis functions are to be computed. Compared with the conventional compressive sensing-based method of moments with characteristic basis functions, the computation time is significantly reduced in terms of constructing the basis functions and recovering the current coefficients, while the accuracy is improved. Finally, both the suggested method and the conventional compressive sensing-based method of moments are used to simulate the bistatic radar cross sections of the perfect electrical conductor cube, cylinder, and missile model. The efficiency and accuracy of the proposed method are verified by the numerical results.

Design of Novel Multiband Radar Absorbers Using Cylindrical Frequency Selective Surfaces

Abstract In this paper, a novel ultra-thin and multi-band radar absorber structure using cylindrical frequency selective surfaces (FSS) is proposed. The unit cell of the structure consists of a curved square ring printed on a cylindrical dielectric spacer to realize strong resonance to achieve efficient absorption of the incident microwave energy. The use of novel cylindrical FSS coating results in a considerable decrease of the radar cross section of a perfect electric cylinder. Furthermore, our studies prove that the proposed absorbing structure can be easily scaled to desired frequencies, and extension to dual- and multiband performances is possible. Meanwhile, the operational principle of the proposed absorbers is briefly introduced.

Design of 6-DOF Tomato Picking Lifting Platform

The tomato picking lifting platform is the carrier for the installation of the picking manipulator, which directly affects the operating range, speed, and picking effect of the picking manipulator. Based on the six degree of freedom motion platform, this paper designs a tomato lifting platform with automatic lifting and automatic leveling functions, which can accurately dock at the designated height to complete the picking operation, and verifies the validity of its parameters and the rationality of the operation movement. First, we analyzed the tomato planting mode and growth characteristics of greenhouse; determined the predetermined trajectory, mechanism travel, and motion form of the lifting platform to complete the lifting process during tomato picking; and determined the basic design parameters of the platform; Secondly, we used SolidWorks to build the three-dimensional model of the lifting platform, and imported it into ADAMS. We used the driving function to complete the dynamic simulation of the virtual prototype of the lifting platform, and obtained the force curve of the electric cylinder and hinge. We analyzed the force on the electric cylinder and hinge of the lifting platform to determine the rationality of the device design. Finally, according to the design requirements and simulation data, we made the prototype of the lifting platform, constructed the motion control system, and carried out relevant experiments. The experimental results show that the maximum rotation angle around the x, y, and z axis is ±10°, the maximum lifting distance is 15 cm, and the maximum load is 50 kg; meanwhile, the average time for the system to reach steady state is 0.309 s, the in-tilt error increases with the increase in biaxial tilt angle, with the maximum error of 1.09°, and the maximum mean square root error of 0.119°, which can meet the automatic operation requirements of the tomato picking manipulator.

An inverse-problem approach to simulating smart control of domestic electric hot water cylinders using electricity demand time-series data.

Smart control of domestic electric hot water cylinders could be used as a relatively inexpensive option to help bridge supply–demand mismatches in highly-renewable electricity grids in many countries. Evaluation of options for the smart control of these cylinders is made difficult by the lack of domestic hot water flow time-series data. In contrast, hot water cylinder electricity demand time-series data, either directly measured or imputed from whole house data, is often much more readily available. In this paper, we propose an inverse-problem approach that uses a physical model of a hot water cylinder to determine hot water flow information from electricity demand data. Once hot water flow information has been determined, it is then possible to simulate smart control of the hot water cylinder element such that it does not interfere with the provision of hot water. We illustrate this approach by using a simple physical model of a hot water cylinder to simulate the hot water flow of 19 houses with electric hot water cylinders from measured time-series electricity data. A smart control case study is then explored where these houses are part of a solar PV microgrid and the cylinder elements are controlled so as to reduce the battery storage needed by the microgrid to reach a certain level of self sufficiency.

A design scheme of vehicle-mounted radar tipping and lifting device

Aiming at the characteristics of compact structure, high integration and limited weight and volume of the mobile platform for vehicle-mounted high-power microwave weapon, this paper carried out an integrated design of lifting Jane and lifting electric cylinder. The performance index, system composition and structure design of the tipping lift device are described in detail. Through checking and testing the performance index, the author guarantees that the design is reasonable and feasible. The device runs smoothly after loading. This meets the functional requirements. It can be used as a reference for the subsequent development of radar overturning lifting system under similar conditions.

Adaptive variable impedance position/force tracking control of fracture reduction robot.

The operation object of robot-assisted fracture reduction surgery is the musculoskeletal tissue with rigid-compliance coupling characteristics. It is necessary to improve the interactive compliance and safety between the reduction robot and the musculoskeletal tissue. An adaptive variable impedance position/force tracking control strategy based on friction compensation is proposed. The stiffness of the reduction robot can be adaptively adjusted according to the contact force between the end-effector and the environment. The Stribeck friction force model of the branch chain electric cylinder is derived to improve the motion control performance. The fracture reduction experiment is completed. The experimental results show that the adaptive variable impedance position/force control strategy can realize position and force tracking in fracture reduction. A safety control strategy is proposed and applied to robot-assisted fracture reduction surgery, which improves the coordination and compliance of the human-robot interaction between the reduction robot and the patient.