最新刊期
期 12 ， 2022
- 摘要：Traditionally, the Lagrangian method is used to deal with the dynamics of multi-body systems. However, in the solution process, Lagrangian multipliers are introduced, which increases the difficulty of solving the explicit dynamics equations. To address the complex problem of modeling the dynamics of a quadruped robot, a single-legged model of quadruped robots based on Udwadia-Kalaba (UK) theory is investigated and a new method for solving its explicit dynamics equations is established. To simplify the process of obtaining the equations, the UK equation is used to deal with the motion constraints. Considering the uncertainty of the realistic environment, a nonlinear controller is designed to track the motion trajectory using the principle of sliding mode control. The results of numerical simulations prove the correctness and effectiveness of the dynamics equations and the controller.关键词：Udwadia-Kalaba theory;Dynamics model;Quadruped robot;Sliding mode control
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发布时间：2023-01-06 - 摘要：The current theory considers that the shape of the deformed flexspline tooth ring neutral line is an isometric line of the cam, which ignores the effect of fit clearance and neutral line's elongation. To reveal the mechanical properties and the tooth positioning on deformed flexspline tooth rings with fit clearance, taking elliptical cam wave generator as an example and considering the fit clearance caused by the clearance between the inner wall of flexsplines, the outer surface of wave generators, the clearance of flexible bearings and the elongation of neutral lines, a contact mechanical model of tooth rings is established. The wrap angle after deformation is introduced as an unknown parameter, and the internal forces in tooth rings in the wrap angle is determined according to the curvature of the neutral line of tooth rings represented by the elliptic equidistant line and the equilibrium equations of the forces. The size of non-contact area, and the internal forces and deformation of tooth ring is solved iteratively with Energy Method according to the displacement conditions on minor axis and the curvature condition at wrap angle and arc length relationship. Based on the results of finite element model, the theoretical results and tooth positions are compared and verified. Both the theoretical analysis and the numerical simulation show that the actual wrap angle of zero clearance fit is far less than 90°, and the full round fitting cam is not true because of the elongation of the neutral line. Reducing fit clearance can effectively increase the contact area and reduce the radial load and the wear of flexible bearings. Considering the wrap angle and the circumferential elongation, more accurate tooth positioning may lead to a more accurate foundation for structural design and meshing analysis of harmonic gears.关键词：Harmonic gear drive;Elliptic cam wave generator;Fit clearance;Mechanical analysis;Energy method
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发布时间：2023-01-06 - 摘要：In order to further improve the stability and accuracy of the pouring trajectory of the heavy-duty casting robot during the pouring operation, a new hybrid four-degree-of-freedom heavy-duty casting robot is taken as the research object, and a trajectory planning method based on the synthesis of the fifth-order polynomial and the sinusoidal acceleration motion law is proposed. The degree-of-freedom of the actuator is calculated by the topological structure theory of the robot mechanism, and the position of the parallel mechanism is solved by the closed-loop vector method, the kinematic position equation of the hybrid mechanism is derived according to the equivalent method and the geometric method. The trajectory planning of the robot is carried out by combining the fifth-order polynomial and the sinusoidal acceleration motion law. The Adams software is used to simulate the trajectory motion of the robot end, and the parameters obtained by the theoretical solution are verified. The results show that the trajectory based on the combination of the fifth-order polynomial and the sine acceleration motion law is smoother and more natural than the fifth-order polynomial, and the maximum speed of the robot end is reduced by 14%, avoiding the vibration due to excessive speed fluctuations.关键词：Composite polynomial;Heavy-duty casting robot;Parallel mechanism;Equation of position;Trajectory planning
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发布时间：2023-01-06 - 摘要：In order to study the influence of dynamic parameters on the gait of biped robots, a passive walking robot with flat feet is taken as the research object, the dynamic equation using Lagrange method and conservation of angular momentum is established and the numerical simulation is carried out. The gait of the flat-foot robot's periodic motion is explained with the help of a stable limit cycle. Based on the bifurcation theory, the effects of the sole, heel, center of mass position, mass ration, and inclined plane inclination on the stable gait of the flat-foot robot are analyzed. The point mapping is used to quickly track the dynamic behavior of the system in the two-dimensional parameter space. The results show that the energy loss of the flat-foot robot mainly occurs when the swinging leg collides with the inclined plane. With the change of the heel, center of mass position, and mass ratio, the gait of the flat-foot robot presents inverse doubling periodic bifurcation. It is found that the flat-foot robot is very sensitive to changes in the position of the heel and the center of mass. At the same time, through the combination of dynamic parameters of the flat-foot robot in maintaining a stable gait in the two-dimensional parameter space and the influence of different foot shapes on the global stability of the system, the importance of the foot shape on the stable walking of the biped robot is proved. The research results provide an important basis for the structural design and energy-saving control of the biped robot.关键词：Biped robot;Limit cycles;Bifurcation and chaos;Dynamic parameters;Parameter space
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发布时间：2023-01-06 - 摘要：To study the wear evolution process and wear law of involute spur gears under the mixed elastohydrodynamic lubrication (EHL) and consider the lubrication conditions, thermal effects and load changes in the wear process of gear pairs, a wear model of gear pairs under mixed EHL is established. The tooth surface wear depth, contact temperature and contact pressure are calculated, and the changes of tooth surface contact pressure and contact temperature in the wear process of the gear pairs are analyzed. The results show that the wear amount at the meshing-in point of the gear pairs is large, and the tooth surface wear can reduce the contact pressure and contact temperature at the meshing-in point.The wear rate near the meshing-in point decreases with the gear meshing. Besides, the influence of tooth surface roughness, input torque and rotational speed on the wear law of spur gear is analyzed. The results show that the reasonable design of gear parameters is beneficial to resist gear wear.关键词：Spur gear;Tooth surface wear;Mixed EHL;Contact temperature;Numerical calculation
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发布时间：2023-01-06 - 摘要：Aiming at the transmission gear system of the head main drive of large shield machines with a diameter of 16 m and in order to explore the dynamic characteristics of the multiple sources parallel drive transmission gear system (including 16 groups of power sources) under real driving conditions, an equivalent dynamic model of 68 DOF bending-torsional coupling of the main drive gear system of the large scale shield machine is established using the lumped parameter method. Considering the influence of the nonlinear factors such as time-varying meshing stiffness, gear transmission error and gear clearance, the model analyzes the time-frequency dynamic response characteristics of the transmission system under the action of multi-source driving torque in actual driving conditions. The results show that the vibration frequency of the system mainly consists of gear meshing frequency and its frequency doubling, and the maximum value of dynamic meshing force occurs at the frequency doubling of corresponding meshing frequency. The amplitude of gear vibration and its meshing force are obviously affected by the input torque fluctuation of hydraulic motors.关键词：Large shield machine;Cutter head main drive system;Gear transmission;Dynamics
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发布时间：2023-01-06 - 摘要：In order to explore the coupling effect of ferrofluids with different carriers on lubrication and gear dynamics, the dynamic model and the ferrofluid lubrication model of the gear system are established. Based on the fourth order Runge-Kutta method, the multi-grid method and multi-grid integration method, the influence of different-carrier ferrofluids on oil film and the distribution of dynamic loads are analyzed. The results show that the film forming characteristics of tooth surfaces can be improved by changing the magnetic fluid base carrier and increasing the magnetic fluid viscosity appropriately. It is mainly reflected in the increase of oil film thickness and stiffness between gear teeth and the decrease of oil film pressure and amplitude of oil film thickness under dynamic loads. When the viscosity of the magnetic fluid increases, the comprehensive stiffness of the gear system also increases. On the contrary, when the vibration speed of the gear pair and the amplitude of the dynamic loads decreased, the impact loads are eventually suppressed, and the dynamic characteristics and NVH（Noise Vibration Harshness） performance of the gear system are improved consequently.关键词：Ferrofluid lubrication;Gear dynamic model;Comprehensive stiffness;Dynamic load
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发布时间：2023-01-06
Theory·Research
- 摘要：Controllable variable stiffness compliant actuator mechanism has the characteristics of high compliance, high environmental adaptability and good man-machine interaction. The variable stiffness compliant actuator mechanism is based on the transmission principle of a four-bar linkage with a zero-length rack. The variable stiffness control can be realized by changing the properties and the winding mode of the elastomer, or the configuration scheme. Through configuration analysis and structure design, the stiffness and torque models of the compliant actuator mechanism are established to reveal its stiffness behavior. The Lagrangian method is used to establish the dynamic model of the compliant actuator mechanism, and the frequency theoretical results are obtained by solving the average stiffness. The virtual prototype is established to motion simulation, which reveals its performance characteristics and verifies the correctness of theoretical analysis. Compared with other similar designs, the compliant actuator mechanism proposed has the characteristics of miniaturization and lightweight with strong applicability. It can be used as a single module and integrated into the exoskeleton system.关键词：Variable stiffness;Compliant actuator mechanism;Reconfigurable;Four-bar linkage with a zero-length rack
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发布时间：2023-01-06 - 摘要：For hybrid electric vehicles (HEVs), the energy management strategy (EMS) can have a significant impact on the fuel economy and emission reduction. In traditional optimization method-based EMS, if fuel economy is the only criterion in the cost function, the result will lead to irrational control signals, thus resulting in deteriorate drivability performance. To deal with this problem, an improved adaptive equivalent fuel consumption minimization strategy (A-ECMS) is proposed, penalty terms are introduced into the cost function to punish frequent engine start/stop events and excessive speed ratio change. Simulation tests are carried out under four kinds of standard driving cycles. By changing the weighting factors, the trade-off between the fuel economy and performance indexes can be evaluated. Finally, the proposed method is compared with the traditional ECMS under the UDDS cycle. The simulation results show that the proposed strategy not only optimizes the fuel economy, but also greatly improves the objectives of the engine start/stop state, changing rate of CVT speed ratio and electric oil pump energy consumption.关键词：Hybrid electric vehicle;CVT;A-ECMS;Drivability;Penalty function
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发布时间：2023-01-06 - 摘要：Aiming at the problem of brake squeal of automobile disc brake, a method based on weighted brake squeal tendency coefficient is proposed to evaluate the brake squeal performance. On the basis of establishing a complex mode finite element model of the disc brake, the validity of the model is verified by the noise bench test. By combining the central composite test design, Response Surface Method （RSM） surrogate model method and the Pointer optimization algorithm, and taking the minimum weighted brake squeal tendency coefficient as the optimization goal, the structural optimization design is carried out for the unilateral disc height, heat sink rib height, elastic modulus and disc cap height of the brake disc. The results show that the optimization design method proposed can significantly improve the efficiency of the optimization solution, effectively reduce the squeal tendency of the disc brake in the full frequency band, and suppress the generation of brake squeal noise.关键词：Brake disc;Brake squeal;Complex eigenvalue method;RSM surrogate model;Optimization design
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发布时间：2023-01-06 - 摘要：The cable-driven parallel robot is a special type of parallel robots whose end-effector is driven by cables instead of rigid rods. A three-degree-of-freedom (3-DOF) under-constrained parallel robot with variable cable mast angle is studied. The inverse kinematics model of the robot is established by using the vector closed-loop principle. According to the Lagrange equation, the dynamics model of the robot is established. Based on the robot PD control theory of model compensation, a PD controller of the robot is designed. Given a motion trajectory of the end-effector of the robot, the pose change of the end-effector is transformed into cable length change through the inverse kinematics of the robot. The cable length is used as the input of the control system. The experimental results verify the correctness of the inverse kinematics and dynamics model of the robot and the effectiveness of the control method.关键词：Cable-driven parallel robot;Variable cable mast angle;Inverse kinematics model;Dynamics model;PD control of robot
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发布时间：2023-01-06 - 摘要：The three degrees of freedom parallel robot with is simple to control, convenient for design and research and has compact structure. In order to study the influence of parallel robots' joint configuration on the size of workspace, two Tau variant parallel robots, 3-RSS and 3-RUU, are taken as the research objects. Then, the spherical hinge and the Hooke hinge are respectively used for analyzing and solving the workspace of the 3-RSS and 3-RUU coaxial drive layout parallel robots. Firstly, a simplified model of the robot is established, and its forward kinematics is solved. Then, the motion range of spherical hinge and Hooke hinge are analyzed as the constraints of the joint so that the three-dimensional workspace of 3-RSS and 3-RUU coaxial drive layout parallel robots is analyzed so as to obtain the workspace boundary. The analysis results show that the 3-RUU coaxial drive layout parallel robot of the same size has a larger workspace than the 3-RSS coaxial drive layout parallel robot. It provides theoretical and technical support for subsequent research on joint selection and workspace of different parallel robots.关键词：Coaxial drive layout;Parallel mechanism;Kinematics analysis;Spherical hinge and Hooke hinge;Workspace
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发布时间：2023-01-06 - 摘要：The high-end transmission equipment such as the new generation of aero-engines faces the challenge of extreme service environments such as high speed, high temperature and heavy load. Scuffing failure is one of the main failure modes of gears, which seriously affects life and reliability. The common Chinese gear scuffing design standards include GB/Z 6413—2003 and HB/Z 84.4—1984. However, the calculation results of these standards for the scuffing loading capacity of gears are different, and difference exists in the application scope of these formulae. Thus, a comparative study of the cylindrical involute gear scuffing capacity standards based on GB/Z 6413 and HB/Z 84.4 is carried out from three aspects: theoretical analysis, parameter comparison and case studies. For FZG A type gears, dozens of case groups have been calculated. The results show that the calculated average friction coefficient of HB/Z 84.4 is higher than that of GB/Z 6413.2, and the calculated results of HB/Z 84.4 are conservative. It is found that calculation results of the surface temperature of GB/Z 6413.1 and GB/Z 6413.2 are consistent in a large range of torque, oil temperature, and speed. However, the difference in the tooth surface temperature of the two methods becomes larger as the tooth module decreases. The temperature results are generally consistent with each other as the tooth module lies within the range of 4-7 mm.关键词：Cylindrical gear;Scuffing standard;Flash temperature method;Integral temperature method
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发布时间：2023-01-06 - 摘要：In order to solve the problem of calculating the air gap magnetic field and torque of slotted-type magnetic couplers, a subdomain analysis model is introduced. The magnetic couplers are divided into five regions along the axis, the boundary equations are established at the interfaces of each region. According to the alternating arrangement characteristics of yoke teeth and the conductor and the vector magnetic potential formulas in yoke teeth and the copper conductor disk are deduced respectively. Due to the end effect, Schwarz-Christoffel mapping is used to modify the coefficient of the flux density at the end face of the cogging. On the basis of obtaining the vector magnetic potential of the yoke iron and conductor respectively, the formulas of the air gap magnetic field and electromagnetic torque are deduced. The structure parameters of the slotted-type magnetic couplers are substituted into the theoretical model to calculate the axial air-gap magnetic field distribution and mechanical characteristic curves. By comparing the results with those obtained by finite element simulation, the accuracy of the theoretical model is verified and the cause of the error is analyzed.关键词：Slotted-type magnetic couplers;Vector magnetic potential;Schwarz-Christoffel mapping;Axial air gap magnetic field;Mechanical characteristic
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发布时间：2023-01-06
Design· Calculation
- 摘要：In order to explore the influence of the variation of hemispherical bevel gear parameters on the dynamic characteristics of the system, a dynamic model of the hemispherical bevel gear pair is established based on the lumped mass method. Based on high-quality hexahedral mesh model, the dynamic transmission performance of hemispherical bevel gears is analyzed by rigid-flexible coupling flexible body dynamics simulation. The influence of parameters such as the size of hemispherical bevel gears and the shaft angle on the motion state of the system is analyzed. The simulation results show that the transmission accuracy, stability and strength of the system change regularly and are negatively correlated with each other under different parameters. The comprehensive performance of hemispherical bevel gears is the best when the diameter of indexing circle is 65 mm and the angle of intersecting shaft is 120°. The flexible multi-body dynamics simulation analysis provides an important reference for the model design, processing and manufacturing of hemispherical bevel gears.关键词：Hemispherical bevel gears;Meshing analysis;Dynamic simulation;Dynamic response;Rigid-flexible coupling
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发布时间：2023-01-06 - 摘要：A lower limb exoskeleton rehabilitation robot can effectively improve the rehabilitation efficiency of patients with impaired lower limb motor function and reduce the workload of rehabilitation physicians. Therefore, a lower limb exoskeleton rehabilitation robot is designed, the relationship between the motion state of the exoskeleton robot and the motion mechanism of each joint is explored, the Lagrange equation to model the dynamics of the lower limb exoskeleton is used and the established virtual prototype model into Adams for dynamic simulation is imported. Further, the torque changes of each joint of the lower limb exoskeleton rehabilitation robot in different motion states are obtained. The data are analyzed to verify the correctness of the data, which provides a theoretical basis for the next step of the physical prototype fabrication and the selection of the actuator.关键词：Exoskeleton robot;Lagrangian equation;Dynamics simulation;Virtual prototype
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发布时间：2023-01-06 - 摘要：Designing an excellent end effector is effective to improve a robot's performance. The kinematics analysis of a circuit board gripper mechanism used in ABB IRB1200 robot is discussed. The working principle of the circuit board gripper mechanism is analyzed; the displacement, velocity and acceleration of the gripper mechanism are solved with analytical methods; the mechanism is analyzed with the theory of kinematic influence coefficient. The motion parameter curve is drawn with the Matlab software in order to verify the analysis results obtained by the analytical method. The kinematics simulation analysis of the mechanism is carried out after defining the connecting rod and the kinematic pair, and giving the motion control function of the driving part, etc. in the UG software; the corresponding motion parameter curve is outputted at the same time. It can be shown that the motion analyses are completely consistent under both the Matlab and the UG environments; strong theoretical support for practical application of the gripper is provided by this motion analysis. This design is effective, which is demonstrated by good operating status of the assembled circuit board gripper mechanism.关键词：Robot;End effector;Kinematics analysis;Analytical method;Kinematic influence coefficient;Matlab;UG
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发布时间：2023-01-06 - 摘要：Aiming at the low efficiency of temperature measurement in coke oven factory, a type of scorpion-like composite robot is designed to measure temperature in coke ovens. The robot works in combination with the structural characteristics of the scorpion. It uses the scorpion's double pincers to lift the lid of the furnace and measures the temperature in the furnace with the infrared temperature measurement of the scorpion tail. In order to verify the rationality of the robot structure, the overall D-H structure of the composite robot is modeled by Matlab, the forward and inverse kinematics of the legs of the composite robot are analyzed, and the working space probability model of the infrared thermometer with both arms and tail is obtained by Monte Carlo method simulation. In order to verify the motion stability of the robot, the stable gait of the composite robot was obtained through Adams simulation. It lays a solid foundation for further robot research.关键词：Coke oven temperature measurement;D-H;Workspace;Stable gait
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发布时间：2023-01-06 - 摘要：Aiming at the fact that the RRT algorithm based on the target bias is easy to fall into local search and has a low search efficiency in complex environment, further improvement is made in the ROS based on the Dobot model and the DIY model. On the basis of creating the manipulator model, the MoveIt! is used for configuration and the model is simplified to improve the efficiency of the collision detection. The extended target change strategy and variable step size are introduced to improve the algorithm which is based on the target biased RRT algorithm. The simulation of the manipulator obstacle avoidance motion planning under different forms of obstacles is carried out in the ROS. The experiments of the obstacle avoidance and obstacle avoidance grasping are carried out on the prototype. Simulation and experimental results show that the proposed improved RRT algorithm can improve the planning success rate and efficiency by 42.9% and 29.2% respectively compared with the RRT algorithm based on target bias.关键词：Manipulator;Obstacle avoidance motion planning;Improved RRT algorithm;Target change;Variable step size
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发布时间：2023-01-06 - 摘要：Taking the gear transmission system of a hybrid vehicle as the research object, the lumped parameter method is used to establish the dynamic model of the transmission system. Under the combined action of the eccentricity error, tooth frequency error, and time-varying meshing stiffness of each gear pair, the numerical method is used to solve the dynamic characteristics of the transmission gear under light-load, low-speed cruising and high-speed overtaking. The transmission system is coupled with the box body, the finite element model of the gear box is established, the dynamic meshing force of the gear is loaded, and the vibration characteristics of the box body during the switching process of the two working conditions are simulated using the Ansys software. A bench test for comparing and verifying the correctness of the dynamic model and simulation calculation is set up. The position of the box with the largest amplitude through the test is obtained, which provides a strong basis for optimizing the structure of the transmission system and improving the vibration characteristics of the gear box.关键词：Hybrid power;Gear system;Dynamic response;Vibration characteristics;Bench test
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发布时间：2023-01-06 - 摘要：Ring chain is the most important part of the scraper conveyor, whose motion characteristics directly affect the capacity and efficiency of the conveyor. Sprocket chain ring of SGZ 1000/3*1000 scraper conveyor is selected as the research object to analyze characteristics of circular chain drive of heavy scraper conveyors. The ring chain drive system is modeled using the SolidWorks software. The kinematics and dynamics simulation of the meshing process of the sprocket and chain ring under different working conditions are carried out using the Adams software. The influence of different working conditions on the ring chain drive system of the scraper conveyor is analyzed. The results show that the deformation of the ring chain and the fluctuation of the load lead to the relative sliding of flat rings in meshing contact, which is the main cause of chain socket wear. Different rotational speeds will affect the stability of the ring chain transmission. Under normal operating conditions, when the speed is maintained at 1.8 m/s, the chain transmission is relatively stable. The results could provide a theoretical foundation in optimizing the design of ring chains of heavy scraper conveyors.关键词：Scraper conveyor;Ring chain;Adams software;Dynamic analysis
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发布时间：2023-01-06
Test·Analysis
- 摘要：With the refinement and complexity of mechanical equipment, the number and types of sensors used to monitor their operating status are increasing. In order to effectively fuse multi-sensor information, complete the information in time and space, and improve the reliability of sensor information, a gear fault diagnosis method based on dynamic weighted feature fusion with maximum information coefficient is proposed. The wavelet packet transform is used to decompose the vibration signals collected by multi-sensor into time-frequency domain; the time and frequency domain features are calculated, the weight of each sensor is calculated by the maximum information coefficient, and the features are fused in parallel; the fused features are input into the support vector machine model for fault classification. Experiments show that the fusion features have better aggregation and are more conducive to classification; under the two speed conditions, the accuracy of fault diagnosis after fusion is 87.72% and 99.16% respectively; the experiment also proves that the diagnosis effect of dynamic weighted fusion is better than that of fixed weight fusion.关键词：Maximum information coefficient;Dynamic weighting;Feature fusion;Fault diagnosis;Support vector machine
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发布时间：2023-01-06 - 摘要：Two kinds of large deflection plane folding hinges, named OSD-LEJ (outside-series-deployed lamina emergent joint) and IOSD-LEJ (inverted-outside-series-deployed lamina emergent joint), are designed with flexible segments arranged in series on the outside, taking into account the inverted design principle. The structures of the two LEJs are designed, and the bending equivalent stiffness formulas are derived. Through the theoretical calculation and the finite element simulation analysis of OSD-LEJ and IOSD-LEJ, the errors between them are about 4% and 4.2% respectively. The correctness of the bending equivalent stiffness formulas is verified. The performances of OSD-LEJ, IOSD-LEJ and large deformation OD-LEJ in the literature with the same feature size are compared and analyzed. The results show that the bending deflections of OSD-LEJ and IOSD-LEJ are 1.2 times and 1.31 times those of the OD-LEJ respectively and the tensile deflections of OSD-LEJ and IOSD-LEJ are 1.16 times and 1.18 times those of the OD-LEJ respectively. Therefore, the OSD-LEJ and IOSD-LEJ have better comprehensive performance. The validity and rationality of structure design of the joints are verified; the idea and reference for the structure design of large deformation hinge LEJ are provided.关键词：Lamina emergent joint;Structure design;Bending equivalent stiffness;Deflection analysis
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发布时间：2023-01-06 - 摘要：A worktable of 3-SPS/UPR parallel mechanism is proposed, which is used to assist the less degree of freedom machine tool to process the surface of the workpiece. The kinematic screw matrix of the 3-SPS/UPR parallel mechanism is established; its degree of freedom is analyzed by the screw theory and verified by the modified Kutzbach-Grübler formula; through the geometric relationship in the mechanism, the closed vector method is used to solve the inverse position solution of the mechanism, and the velocity Jacobian matrix of the mechanism is derived; the workspace of the mechanism is solved by three-dimensional dynamic search method; the kinematics of the parallel worktable is simulated by the Adams software. The 3-SPS/UPR parallel mechanism can carry out the movement of two translation and two rotation, improve the machining efficiency and quality of the machine tool, increase the machining range of the machine tool and improve the surface machining ability of the machine tool.关键词：3-SPS/UPR parallel mechanism;Degree of freedom;Position inverse solution;Workspace;Adams software
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发布时间：2023-01-06 - 摘要：The compression ratio of engines is one of the factors affecting the thermal efficiency of gasoline engines. The engine needs to match the best compression ratio according to the actual conditions to meet the actual requirements. Therefore, variable compression ratio technology can help achieve a balance between engine power and fuel economy under different operating conditions. Thus, a multi-link mechanism for variable compression ratio engine is designed based on the engine principle. The correctness of the mechanism design is verified by kinematics theory modeling calculation and comparative analysis of simulation results. Based on multi-body dynamics theory and considering boundary conditions such as combustion load and crankshaft speed comprehensively, the variation rule of the multi-link mechanism with control shaft rotation angle is explored; the kinematic and dynamic characteristics of the multi-link mechanism under different compression ratio conditions are evaluated, compared and analyzed in detail with those of the traditional single-link mechanism. The results show that the multi-link mechanism can realize real-time variable compression ratio to meet the actual operating conditions, has mechanical advantages in power amplification characteristics and restraining friction between piston and cylinder wall, and brings additional dynamic benefits in engine vibration.关键词：Engine;Variable compression ratio;Multi-link mechanism;Mechanism design;Multi-body dynamics
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发布时间：2023-01-06
Development·Application
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