Summary of CPAS EDU Testing Analysis Results

This paper studies the effects of reducing the index of the original ADAMS (automatic dynamic analysis of mechanical systems) formulation. For this, a pilot computer program MECH-SIM (MECHanical SIMulations) was developed on the basis of the original ADAMS attributes such as sparse tableau formulation (STF) and backward difference formula (BDF) [1]. The STF implemented in the original ADAMS computer program uses differential and algebraic equations (DAE). In the new formulation it eliminates the three relations connecting the body angular velocities and the angular momentum. It also reformulates the implicit force equations by substituting their functions directly into the corresponding differential equations of motion. The above reduction maintains a reasonable number of equations when the geometric constraints stabilize the velocity and/or the acceleration constraints. A method is found to measure ‘the drift’ allowed by the velocity or acceleration constraints. This permits the use of constraints stabilization only ‘when needed’. Consequently, the BDF error control improves maintenance of the efficiency of the method. The pilot computer program MECH-SIM incorporates these improvements. The program was used to test the numerical accuracy and efficiency on mechanical systems used in agricultural mechanization, industrial equipment and auto suspensions. Hence, such results can be extended to the modern ADAMS computer program.

Dynamic simulation of auto-centralizer for horizontal well traction robot based on ADAMS

Conventional models for mechanical rotors based on Automatic Dynamic Analysis of Mechanical Systems (ADAMS) are over-constraint. This paper proposes a new method for simulating the stiffness and damping of bearings using bushing and other kinematic pairs. Analysis and Simulation for balance of rigid rotors by ADAMS were performed. To reduce the imbalance inertial force, the balance weight of a take-up machine has been optimized. The results were verified by the prototype test. Our results suggest a more effective method for balance of mechanical rotors in the design stage.

Failures associated with braking systems and insufficient following distances are primary causes of rear-end collisions and rollovers involving trucks. Through a comprehensive analysis of hazardous states during braking and their contributory factors, a vehicle en-route status detection device has been developed. This device can acquire real-time data on load, vehicle speed, and the state of the braking system. Hazard identification based on single parameters such as brake shoe wear, abnormal brake shoe temperatures, and brake light failures has been conducted using sensor data. By performing a dynamic analysis of vehicles during braking, a braking distance calculation model was established. This model was calibrated through vehicle coasting tests. The reliability of the braking distance model was validated through both Automatic Dynamic Analysis of Mechanical Systems (ADAMS) simulation and practical vehicle tests. Considering the relationships among the following distances, brake line pressures, and braking distances, a novel multi-parameter identification method for hazardous states during the braking process is proposed.

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.

Implementation of a ball inverted pendulum with omnidirectional moving ability using a robust fuzzy control strategy

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.

In this study, a 3D model of the shovel motion based multi-body system dynamics in the Automatic Dynamic Analysis of Mechanical Systems (ADAMS) environment was developed. The kinematics model of the shovel was modeled as a multi-body system, which comprises the lower, upper, and the attachment mechanisms. The Euler–Lagrangian equations were employed as the computational framework to describe the dynamic behavior of the model. A virtual prototype of the shovel was built in the ADAMS software environment. This environment allows the visualization of a 3D motion of the general mechanical system and the prediction of interference of the moving components of the shovel. The numerical analysis and animation of digging, swinging, and dumping motions for the shovel were performed. The superimposed display of the deployment for the shovel in three phases allows a detailed examination of the dynamic interference among assembly components. This research provides a solid foundation for further shovel dynamics performance studies.

This is the third in a series of four papers (Parts 1 to 4) looking at the application of computer-based analysis methods to model vehicles and simulate vehicle handling. The material contained in these papers is based on a study carried out in order to investigate the influence of suspension and tyre modelling on the outputs predicted by vehicle handling simulations. The papers deal with analysis methods, vehicle modelling (both in the previous Issue), tyre modelling and handling simulation. In this paper an overview of the use of tyre models in vehicle dynamics is provided. This is followed by a more detailed description of three tyre modelling approaches that can be used for handling simulations. A description is also provided of a computer-based modelling system where FORTRAN routines represent the various models and a computer model of a tyre test rig is used to interrogate the models and data before integrating these into a full vehicle handling simulation. The use of this system to compare the accuracy of the tyre models under consideration is also presented. The examples used to illustrate the concepts explained throughout this series of papers have been generated using the ADAMS (Automatic Dynamic Analysis of Mechanical Systems) program.

Based on UG and Automatic Dynamic Analysis of Mechanical System (ADAMS), the 3D model of differential was constructed and the real-time dynamic simulation of differential was achieved. The effects of gear backlash between half axle gears and planetary gears on the vibration of differential are studied. To increase the credibility of simulation results , the contact forces between half axle gears and planetary gears were calculated based on the Hertz elasticity impact theory.

Based on the simplex style of the traditional medical beds at home and abroad presently, a new folding mechanism of multifunctional medical bed was presented. After theoretical analysis, an optimal structure was selected. This mechanism consists of several planar four-bar linkages. It has one degree of freedom, which means it can be driven by only one driving torque to achieve multi-states changes. Therefore, it could save the space and reduce the weight of the bed as much as possible. The analysis of mechanism was carried out, simulation and stability were performed as well. A proto was established in the software named Automatic Dynamic Analysis of Mechanical Systems (ADAMS) to verify feasibility of the mechanism and the correctness of the design principle. It is an ingenious and brief design, which provides useful information for future research about folding medical bed.

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.

The performance of landing gear retraction mechanism in aircraft directly affects the safe operation of the aircraft. When landing gear retraction mechanism in a military aircraft was designed, the virtual prototype model was established by UG (Unigraphic) software, and the motion analysis and interference checking were carried on. Then the digital prototype model was established in ADAMS (Automatic Dynamic Analysis of Mechanical System) software, and the virtual simulation parameters were set to analyze the aerodynamic drag, mass, inertia forces and the load of actuator cylinder. Thus the kinematic and dynamic properties could be got to simulate real working situation, which could verify the correctness of the design and provide evidence for further optimal design of the machine.

The optimum design method of moving characteristics of 126kV Vacuum Circuit Breaker (VCB) with spring operation mechanism is presented in this paper. Mathematical model and virtual prototype of 126kV VCR arc set up, and the dynamic and kinetic characteristics arc described as well. ADAMS (Automatic Dynamic Analysis of Mechanical System) is applied in the dynamic simulation to solve the complex calculation of moving characteristics. Satisfactory simulation results can be obtained by iterative modifying parameters of the model, and it is shown that this model can be used to study the dynamic features of VCB and to provide a good basis for circuit breaker optimum design.

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.