Automatic Dynamic Analysis Of Mechanical Systems Research Articles

Kinematic and Dynamic Analysis of Eccentric Balanced Positive Torque Pumping Unit

Beam pumping units have numerous energy transfer links, significant net torque fluctuations and negative net torque in gear boxes, which lead to a high installed power and low system efficiency. In order to improve the efficiency of the pumping unit, in this paper, an eccentric balanced positive torque pump unit was designed based on the principle of eccentric balance that is small in size and adopts a flexible energy transfer system instead of a rigid structure to significantly reduce the energy transfer link. The kinematics and dynamics of the eccentric balanced positive torque pumping unit were analyzed and the ability to operate with positive torque over the entire cycle was verified using theoretical computations. And the results of the theoretical calculation were verified by using the virtual prototype simulation and analysis software ADAMS (Automatic Dynamic Analysis of Mechanical Systems); the pumping unit was optimized for relevant parameters such as the balance crank angle λ and the counterweight center of mass offset angle δ. Indoor testing and comparative field application have demonstrated that the installed power has been reduced by 80%, the weight of the entire prototype has decreased by 25% and the system efficiency has reached 24.3%. Additionally, electricity savings of over 50% have been achieved. These results indicate that the pumping unit has been designed correctly, has high reliability and has significantly improved system efficiency while also providing an obvious energy-saving effect.

Analysis and Test of the Tillage Layer Roll-Type Residual Film Recovery Mechanism

With the extensive use of plastic film mulching in planting, the amount of residual plastic film in soil has been increasing, causing soil and water pollution, harming crop growth, and reducing agricultural product quality and yield. In response to this issue, this study proposes a roll-type residual film recovery mechanism using the tillage layer method. The structure and operation principles of this system are discussed, and a detailed analysis of its key components and working process is provided. The lifting cutter operates at a speed of 22.37 rad/s, the pick-up drum at 4.58 rad/s, the roll forward rotation picks up the film at 13.74 rad/s, and the roll reverse film rotation unloads the film at 17.57 rad/s, with the unloading wheel rotating at a speed of 4.5 rad/s. ADAMS (software of automatic dynamic analysis of mechanical systems) Version No.2019 is used for modeling and analysis, and the displacement and velocity change patterns of MARKER_499, MARKER_500, and MARKER_505, which are marked points of the spring-tooth tips and are found to be the same. The maximum resultant displacement of MARKER_499 and MARKER_500 is 22.146 mm when picking up plastic film and 17.047 mm when unloading plastic film. Meanwhile, the maximum resultant displacement of MARKER_500 and MARKER_505 is 231.715 mm in the film-picking area and 234.028 mm in the film-unloading area. After analyzing the velocity of MARKER_499 during picking and unloading of the film, it was determined that the absolute velocity for the picking direction was 79,809.407 mm/s, and for the unloading direction it was 10,2266.168 mm/s. Bench tests show a tillage gathering rate of 71.6% and a surface gathering rate of 83.4%, meeting the performance requirements of the roller-type residual film recovery mechanism. These findings provide a theoretical basis for the design of the structure and operational parameters for the roll-type residual film recovery mechanism using the tillage layer method.

Simulation evaluation of underwater robot structure and control system based on ADAMS

Abstract The twenty-first century is the century of marine resources. The ocean is a treasure of biological resources, energy, water resources and mineral resources, and it would gradually become the “second space” of mankind. In the next few years, it would be more and more relevant to human life. Many scholars have realized the importance of the ocean and began to vigorously develop and use the ocean. Underwater robot is a means for human beings to explore and develop the ocean, and it would be widely used in this field. The development and promotion of underwater vehicles are of great significance to resource development, economic development, and national security. With the increasing shortage of land resources, the development and utilization of marine resources have received increasing attention. The direct exploitation of marine resources by humans would have adverse effects, so the underwater robot technology has developed rapidly in recent years. However, at present, most underwater robots are driven by electric turbines. The underwater working environment requires that the underwater motor has good sealing performance, so its structure is complex and expensive, and it is rarely used in ordinary underwater operations. In recent years, intelligent robots have been used more and more, but because of the complexity and uncertainty of the underwater working environment, there are many uncertain factors. Therefore, it is very meaningful to carry out stability control for it. The research results showed that the displacement, stability, and other corresponding test curves of each component can be obtained by establishing a simple model with software and through ADAMS (Automatic Dynamic Analysis of Mechanical Systems) simulation analysis. This can simulate the movement of real objects in the real environment and find the existing problems, so as to provide a reference for the actual underwater robot design. In this way, the development cycle and production costs can be reduced. This article analyzed the structure and control system of the underwater vehicle based on ADAMS simulation. The results showed that the dynamic stability of the underwater vehicle based on ADAMS simulation analysis was improved by 4.67% compared with the underwater vehicle before optimization.

Modeling and driving function optimization of tree climbing robot

To ensure the tree-climbing robot can complete the up-tree or down-tree process, its arms need to adjust the displacement of the push rod in real-time according to the diameter size of the tree trunk so that the tire can smoothly bypass the smaller tree pile. However, the irregular shape of the trunk surface makes the inflatable tire vibrate during rolling, which will reversely affect the performance of the push rod. Based on this, the three-dimensional model of the tree-climbing robot is established by Solid Works software, and the kinematics simulation model of the tree-climbing robot is established by Automatic Dynamic Analysis of Mechanical Systems (ADAMS). The kinematics simulation analysis is carried out. According to the tire displacement curve of the tree-climbing robot, the optimal solution of the push rod driving function is solved. Under the condition of ensuring the trajectory of the spiral rise is unchanged, the mean square deviation of the distance between the two arms of the tree-climbing robot is the smallest, and the push rod is the least affected by the reverse effect of the tire. The simulation results show that under the condition of the optimal solution, the frequency distribution and amplitude of the four springs are basically the same. The force of the four springs is uniform, and the reverse influence of the tires on the two push rods is minimized, which is conducive to the improvement of the stability of the tree climbing robot.

Design and Research of a Novel Piezostack-Driven Jetting Dispenser With a Diamond Spring

A novel piezoelectric jetting dispenser is proposed for microelectronic packaging in this article. It adopts a piezoelectric drive, a lever displacement amplifier, and a recovery system with double springs in a staggered position. The automatic dynamic analysis of mechanical systems (ADAMSs) simulation model of the dispenser is established and first applied to the study of the high-frequency response performance. The displacement curve and the velocity curve of the impactor are obtained at the frequency of 200 and 500 Hz. The test results prove that the ADAMS model is feasible. Based on dispensing experiments, the volume and the volume error of a drop at different dispensing frequencies are studied. The volume of a drop is 8.5 nL at the frequency of 800 Hz. The maximum relative error of the droplet volume is less than ±7.2% at the frequency of 200, 300, and 400 Hz.

Construction and Simulation of Biomechanical Model of Human Hip Joint Muscle-Tendon Assisted by Elastic External Tendon by Hill Muscle Model.

Based on the Hill muscle model (HMM), a biomechanical model of human hip muscle tendon assisted by elastic external tendon (EET) was preliminarily established to investigate and analyze the biomechanical transition between the hip joint (HJ) and related muscle tendons. Using the HMM, the optimal muscle fiber length and muscle force scaling variables were introduced by means of constrained optimization problems and were optimized. The optimized HMM was constructed with human parameters of 170 cm and 70 kg. The biomechanical model simulation test of the hip muscle tendon was performed in the automatic dynamic analysis of mechanical systems (ADAMS) software to analyze and optimize the changes in the root mean square error (RMSE), biological moment, muscle moment distribution coefficient (MDC), muscle moment, muscle force, muscle power, and mechanical work of the activation curves of the hip major muscle, iliopsoas muscle, rectus femoris muscle, and hamstring muscle under analyzing the optimized HMM and under different EET auxiliary stiffnesses from the joint moment level, joint level, and muscle level, respectively. It was found that the trends of the output joint moment of the optimized HMM and the biological moment of the human HJ were basically the same, r2 = 0.883 and RMSE = 0.18 Nm/kg, and the average metabolizable energy consumption of the HJ was (243.77 ± 1.59) J. In the range of 35%∼65% of gait cycle (GC), the auxiliary moment showed a significant downward trend with the increase of EET stiffness, when the EET stiffness of the human body was less than 200 Nm/rad, the biological moment of the human HJ gradually decreased with the increase of EET stiffness, and the MDC of the iliopsoas and hamstring muscles gradually decreased; when the EET stiffness was greater than 200 Nm/rad, the increase of the total moment of the extensor muscles significantly increased, the MDC of the gluteus maximus and rectus muscles gradually increased, and the gluteus maximus and hamstring muscle moments and muscle forces gradually increased; the results show that the optimized muscle model based on Hill can reflect the law of human movement and complete the simulation test of HJ movements, which provides a new idea for the analysis of energy migration in the musculoskeletal system of the lower limb.

Dynamic Performance Analysis of Cage in Four-Point Contact Ball Bearing

Due to the special structure of double-half inner rings, four-point contact ball bearings are prone to uneven forces in the inner raceway during movement, which affects the dynamic performance of the rolling element and cage, and even leads to cage sliding. Dynamic performance of the cage is an important factor affecting the working stability of bearings. In this paper, in order to grasp the operation law of the cage so as to guide the application of four-point contact ball bearings, the dynamic model of four-point contact ball bearings is established by the secondary development of Automatic Dynamic Analysis of Mechanical Systems (ADAMS). The dynamic performance of the cage is analyzed and evaluated with the indexes of vortex radius ratio and vortex velocity deviation ratio of the cage centroid trajectory. The results show the following: the cage stability increases and then decreases to a certain degree with rotating speed-rise; it increases and then decreases with the increase in the pure axial load; under a combination of axial and radial load, the cage moves more smoothly with smaller radial force. Rotating speed has little effect on cage stability, while radial force has a great influence on cage stability, followed by axial load. In order to verify the simulation results, a test bench for rolling bearing cages is developed, and the accuracy of the simulation results is verified by the test results.

Kinematics and dynamics simulations of cold orbital forging machines based on ADAMS

The vibration of cold orbital forging (COF) machines is detrimental to the quality of the forged part. Therefore, it is necessary to carry out kinematics and dynamics analyses, study the vibration of the COF machine, and provide effective methods for reducing the vibration. In terms of kinematics and dynamics analyses, the mathematical modeling and model solving processes are complicated, and it takes a long time to obtain the kinetic and vibration performances of the COF machine. In this study, the kinematics and dynamics models of the COF machine were investigated. Subsequently, automatic dynamic analysis of mechanical systems (ADAMS) was applied to conduct kinematics and dynamics simulations. The simulation process was convenient and time-saving, and the simulation of the COF machine was effectively verified by conducting an experiment. Based on the simulation results, the kinetic and vibration performances of the COF machine were studied. In addition, a structure optimization method for the COF machine is proposed. Based on the singularity stability theory, the Hopf bifurcation and chaos phenomena are less likely to occur on the optimized COF machine, and therefore the vibration of the optimized COF machine is stable. Meanwhile, the structure optimization method was proven to be effective in reducing the vibration of the COF machine, which improves the quality of the forged part.

Kinematics analysis and gait planning for a hemiplegic exoskeleton robot

Background: As the world's aging population increases, the number of hemiplegic patients is increasing year by year. At present, in many countries with low medical level, there are not enough rehabilitation specialists. Due to the different condition of patients, the current rehabilitation training system cannot be applied to all patients. so that patients with hemiplegia cannot get effective rehabilitation training. Methods: Through a motion capture experiment, the mechanical design of the hip joint, knee joint and ankle joint was rationally optimized based on the movement data. Through the kinematic analysis of each joint of the hemiplegic exoskeleton robot, the kinematic relationship of each joint mechanism was obtained, and the kinematics analysis of the exoskeleton robot was performed using the Denavit-Hartenberg (D-H) method. The kinematics simulation of the robot was carried out in automatic dynamic analysis of mechanical systems (ADAMS), and the theoretical calculation results were compared with the simulation results to verify the correctness of the kinematics relationship. According to the exoskeleton kinematics model, a mirror teaching method of gait planning was proposed, allowing the affected leg to imitate the movement of the healthy leg with the help of an exoskeleton robot. Conclusions: A new hemiplegic exoskeleton robot designed by Shenzhen Institute of Advanced Technology (SIAT-H) is proposed, which is lightweight, modular and anthropomorphic. The kinematics of the robot have been analyzed, and a mirror training gait is proposed to enable the patient to form a natural walking posture. Finally, the wearable walking experiment further proves the feasibility of the structure and gait planning of the hemiplegic exoskeleton robot.

Straw/Spring Teeth Interaction Analysis of Baler Picker in Smart Agriculture via an ADAMS-DEM Coupled Simulation Method

In this paper, a new coupling simulation method is proposed for baler picker using automatic dynamic analysis of mechanical systems (ADAMS) and discrete element method (DEM). Field tests are carried out to verify the accuracy of the simulation model. By using the coupling method, not only was it obtained that the forward velocity (FV) and the ground clearance of spring teeth (GCST) are positively correlated with the pick-up loss rate (PLR), but also that the blockage of the picker mainly occurs in the straw pushing area, and an optimization plan is proposed. Through the analysis of the acting force (AF) between the roller and the track groove, we speculate that the structure of the track groove in a certain area is defective. The coupling method and optimization scheme proposed in this paper can provide a reference for the optimal design of the picker.

Variable universe fuzzy control of the lateral stability of forklift trucks based on roll grading

Based on the structural analysis and the roll mechanisms of counterbalanced forklift truck, a novel type of 3-link hydraulic supporting mechanism is designed as an actuator for forklift anti-rollover control. A rollover grading control strategy of the lateral stability of counterbalanced forklift truck is proposed, which is used to design a variable universe fuzzy controller. The variable universe fuzzy control of the first-order roll is utilized when the forklift is in the first-order roll, whereas the variable universe fuzzy control of the second-order is used when the forklift is in the second-order roll. A virtual prototype model of forklift is built in Automatic Dynamic Analysis of Mechanical Systems (ADAMS). The co-simulations and vehicle tests are implemented, the results indicate that the lateral stability and active security of the forklift could be improved effectively by using the variable universe fuzzy control strategy of the lateral stability of forklift truck based on roll grading.

Research on dynamics of bouncing ball in triboelectric nanogenerator

Bouncing ball based Triboelectric Nanogenerator (BB-TENG) can be used to harvest vibrational energy and sense signal for self-powered sensor in the non-resonant zone because of its non-spring vibration system. The energy harvesting efficiency and sensing effectiveness are significantly affected by the dynamics of the bouncing ball. However, due to the chaotic and nonlinear mechanics, the dynamics of the bouncing ball inside BB-TENG and the corresponding influencing factors have not yet been revealed, which restricts the development of high-efficiency BB-TENG. In this work a method based on dynamics simulation and test bench experiment is to be proposed and the ‘Takeoff’, ‘Well-Contact’, ‘Self-Spin’, and ‘Rich-Contact’ of the bouncing ball with the plate electrodes will be investigated. The kinetic model established based on the Automatic Dynamic Analysis of Mechanical Systems (ADAMSs) is verified through experiments to confirm the reliability of the simulation results. It is found that ‘Well-Contact’ of the bouncing ball makes BB-TENG harvest energy efficiently. The factors for ‘Well-Contact’ and their influence are investigated, and the critical frequencies for ‘Well-Contact’ of the bouncing ball at each vibration excitation amplitude are obtained. ‘Self-Spin’ of the bouncing ball produced by unbalanced excitation torque is found to increase energy harvesting, and the excitation frequency significantly determines the energy of the ‘Self-Spin’. When the external excitation acceleration reaches a critical value, the ‘Rich-Contact’ of the bouncing ball is found, and the amount of charge transfer for BB-TENG will not increase, which is termed saturated condition. Therefore, the results of this work help improve the design and application of high-efficiency BB-TENG.

Optimal Design of High-Voltage Disconnecting Switch Drive System Based on ADAMS and Particle Swarm Optimization Algorithm

This paper focuses on the analysis of the stability of the GW17 high-voltage disconnecting switch drive system. Firstly, the optimization model of the disconnector is established, and the simulation analysis is carried out by ADAMS (Automatic Dynamic Analysis of Mechanical Systems) and the simulation results are verified by experiments. Afterwards, ADAMS optimization design and particle swarm optimization algorithm (PSO) are used to optimize the drive system of the disconnector, and the results are verified on the experimental platform. After optimization, the space rod is reduced by 15 mm, the minimum corner angle of the lower conductive rod is reduced by 71.0%, the minimum folding arm angle is reduced by 88.7% and the maximum force of the ball pair is reduced by 35.7%, which realizes the lightweight of the rod, reduces the wear of the ball pair, and improves the stability of the equipment operation.

Adaptive fuzzy backstepping control of underactuated multi-cable parallel suspension system with tension constraint

Multi-cable parallel suspension system (MCPSS) is designed to lift a heavy object with rapid development of deep resources exploitation. An adaptive fuzzy backstepping control strategy combining with nonlinear disturbance observer is studied to synthetically control the posture for the underactuated MCPSS with tension constraint in this article. Firstly, a theoretical modelling of the MCPSS with boundary constraints is derived by the extended Hamilton’s Principle. Secondly, the parameter uncertainties and time-varying disturbances are compensated by the fuzzy system and nonlinear disturbance observer, respectively. Thirdly, an adaptive fuzzy backstepping feedback controller based on the reference model is proposed to suppress vibration and control posture of the suspension platform. Finally, an Automatic Dynamic Analysis of Mechanical Systems (ADAMS) simulation and a numerical calculation are used to illustrate the theoretical model and the proposed control performance.

Type Synthesis and Dynamics Performance Evaluation of a Class of 5-DOF Redundantly Actuated Parallel Mechanisms

This paper presents a five degree of freedom (5-DOF) redundantly actuated parallel mechanism (PM) for the parallel machining head of a machine tool. A 5-DOF single kinematic chain is evolved into a secondary kinematic chain based on Lie group theory and a configuration evolution method. The evolutional chain and four 6-DOF kinematic chain SPS (S represents spherical joint and P represents prismatic joint) or UPS (U represents universal joint) can be combined into four classes of 5-DOF redundantly actuated parallel mechanisms. That SPS-(2UPR)R (R represents revolute joint) redundantly actuated parallel mechanism is selected and is applied to the parallel machining head of the machine tool. All formulas of the 4SPS-(2UPR)R mechanism are deduced. The dynamic model of the mechanism is shown to be correct by Matlab and automatic dynamic analysis of mechanical systems (ADAMS) under no-load conditions. The dynamic performance evaluation indexes including energy transmission efficiency and acceleration performance evaluation are analyzed. The results show that the 4SPS-(2UPR)R mechanism can be applied to a parallel machining head and have good dynamic performance.

Optimized design and experiment of a fully automated potted cotton seedling transplanting mechanism

In order to improve the accuracy and stability of transplanting machine seedling picking, a seedling pick-up mechanism was designed, which was controlled by a controller and driven by brushless DC servo motor. At the same time, the parameters of the seedling manipulator were optimized: the mathematical model for the seedling pick-up mechanism was established. According to the predetermined trajectory requirements, the objective function and constraint conditions were proposed, and then the optimal size was obtained by a multi-objective genetic algorithm. At last, Automatic Dynamic Analysis of Mechanical Systems (ADAMS) software was used to simulate and analyze the kinematics and trajectory of the seedling pick-up mechanism, and the mechanism was tested to verify the effectiveness of the mechanism prototype. The experiments showed that the success rate of seedling picking was 94.32%, the rate of acceptably planted seedlings was 96.67%, and the rate of excellently planted seedlings was 63.48%. Keywords: cotton seedling, transplanting machine, kinematic model, optimized design, test, full automation DOI: 10.25165/j.ijabe.20201304.5317 Citation: Xue X L, Li L H, Xu C L, Li E Q, Wang Y J. Optimized design and experiment of a fully automated potted cotton seedling transplanting mechanism. Int J Agric & Biol Eng, 2020; 13(4): 111–117.

Influence of control device on store separation from an open cavity

The influence of a flow control device on store separation from an internal cavity is examined using a wind-tunnel drop-test (WTDT) method, which is based on dynamic similarity. In the wind-tunnel test, an open cavity with a length-to-depth ratio of R=7.76 is employed. An ejection mechanism driven using two cylinders is designed using the CATIA software and is virtually simulated using automatic dynamic analysis of mechanical systems (ADAMS). The store is designed using the light Mach scaling method. Conditions involving a cuboid control device (CCD) and no control device (NCD) for the open cavity are compared. Furthermore, both the scaled and higher ejection forces are employed in the test. The results indicate that a CCD installed in front of the cavity can effectively improve the aerodynamic characteristics of the flow field, which is beneficial for the store to rapidly pass through the interferential flow field of the cavity. Owing to the pitching moment acting on the internal store, the head of the store exhibits a nose-up configuration under both the CCD and NCD conditions; however, the value of the pitching moment coefficient in the CCD case is smaller than in the NCD case.

Conveyor belt structure of belt dryer: Analysis and optimization

The chain drive conveyor belt (CDCB) of the belt dryer is prone to generate impact load during operation, and the conveyor belt bedplate (CBB) will cause fatigue damage and fracture. This study presents an approach for calculating fatigue life, which combines the automatic dynamic analysis of mechanical systems (ADAMS), finite element analysis software (ANSYS), fatigue analysis software (FE-SAFE), and experimental stress analysis. The virtual prototype model for simulation of the CDCB is established, and its motion stability, contact impact force and motion trajectory are analyzed. The study shows that the chain drive polygon effect will cause periodic changes in velocity, and the motion trajectory has very good similarity. The stress experiment results show that the stress was considerable during the chain drive meshing process. The finite element analysis results show that the maximum stress of the old CBB is higher than the yield strength of the material, and the equivalent stress of the new CBB is lower than that of the old CBB. The area of the maximum stress of old CBB presents a fracture, which indicates the fatigue failure of the old CBB. The finite element calculation results were imported into FE-SAFE for fatigue life analysis, which compared the fatigue cycle number and safety factor of the old CBB and the new CBB. The results show that the new CBB can extend the service life of the belt dryer. The proposed analytical method for fatigue life is simple and effective and can serve as a reference for the fatigue life analysis of the key components of the belt dryer.

Synthesis and Verification of Finite-Time Rudder Control with GA Identification for Electric Rudder System

The electric rudder system (ERS) is the executive mechanism of the flight control system, which can make the missile complete the route correction according to the control command. The performance and quality of the ERS directly determine the dynamic quality of the flight control system. However, the transient and static characteristic of ERS is affected by the uncertainty of physical parameters caused by nonlinear factors. Therefore, the control strategy based on genetic algorithm (GA) identification method and finite-time rudder control (FTRC) theory is studied to improve the control accuracy and speed of the system. Differently from the existing methods, in this method, the difficulty of parameter uncertainty in the controller design is solved based on the ERS mathematical model parameter identification strategy. Besides, in this way, the performance of the FTRC controller was verified by cosimulation experiments based on automatic dynamic analysis of mechanical systems (ADAMS) (MSC software, Los Angeles, CA, USA) and matrix laboratory (MATLAB)/Simulink (MathWorks, Natick, MA, USA). In addition, the advantages of the proposed method are verified by comparing with the existing strategy results on the rudder test platform, indicating that the control accuracy is improved by 70% and the steady-state error is reduced by at least 50%.

Performance Analysis of Super Twisting Sliding Mode Controller by ADAMS–MATLAB Co-simulation in Lower Extremity Exoskeleton

Lower extremity exoskeleton is a kind of wearable robot and is used both in medical and industrial applications for different purposes. In the medical field it is used as a piece of therapeutic equipment and in the industry especially in defense, to carry heavy loads. This paper deals with the analysis of the performance of super twisting sliding mode controller (STSMC) on tracking the motion of the wearer by the lower extremity exoskeleton using automatic dynamic analysis of mechanical systems (ADAMS)–MATLAB co-simulation during walking and step climbing and the results are compared with a conventional PID controller. The model of the lower extremity exoskeleton is developed by solid-works software and the model of the human body is done with ADAMS software. Super twisting sliding mode controller (STSMC) is designed and simulated with Simulink. This paper also aims to develop a mathematical model of the system and analyze the performance of STSMC to control hip, knee, and ankle movements and also to point out the advantages of the ADAMS–MATLAB co-simulation over the conventional methods of modeling and simulation analysis of the controller to control the exoskeleton. Stability analysis of the controller is also done.