This study proposed and verified a new idea for the crushing system of a mobile pellet harvester. As the key components of the crushing mechanism, the theoretical design calculation was given, and Ansys software was used to verify the feasibility of the design, specifically by computing the strength and stiffness. Field tests were conducted, and the test results met the requirements. This design can promote the further development of a mobile pellet harvester.
In order to improve the efficiency of identifying parameters using the maximum likelihood method and to avoid the sensitivity of initial values, a proposed method that combines the advance and retreat method with the micro-genetic algorithm allows the initial value, the iterative increment, and the search interval to be gradually changed, and the initial value to start from zero, which ensures a stable and fast convergence compared with other algorithms.
A comparison between the results obtained by the MsP method and the numerical integration method proves that the former is ideal and credible in most regions. The effects of the time-varying parameters and the nonlinear deenthing caused by the gear teeth clearance on the amplitude–frequency characteristics of TsSCS components are studied. This is a part of research on transmission gears' thermal deformation for application in warship power rear drive systems.
In this paper, the fractional model of the asynchronous motor rotor was firstly established with a peculiar memory characteristic, and the introduced harmonic response was able to fit the reality well. Then, we set high rigidity and less mass as optimization functions and transform them into the problem of the first-order frequency and mass. In order to find the optimal parameters, an accelerated optimization method based on response surface is proposed.
This paper investigates the influence of friction effects on a gear-rotor system in compressed air energy storage (CAES), a new mathematical model of the system is established, and some new vibration characteristics of the gear-rotor system are shown in this paper. The results obtained in this paper will provide a reference for the study and design of a gear-rotor system in CAES.
This paper proposes a new 13 degrees of freedom equivalent kinematic model for the human upper limb and fully considers the movement characteristics of human upper limbs in anatomy. The proposed model can be utilized to analyze the human upper limb workspace and joint motions. Furthermore, the model can effectively evaluate the existing upper limb exoskeleton and provide suggestions for structural improvements in line with human motion.
This paper proposes a novel, 4 degrees of freedom, end-effector-based upper limb rehabilitation robot with space training. The robot can assist the human upper limb in performing rehabilitation training of the shoulder flexion/extension and adduction/abduction and elbow flexion/extension. Different from the desktop-type end-effector-based robot, the proposed robot can provide a wide range of shoulder flexion/extension training and cover the range of movement of the human upper limb.
Rotary forging with double symmetry rolls (DSRs) is a new metal plastic forming technology developed on the basis of conventional rotary forging with a single roll, which uses a pair of symmetrical cone rolls to realize continuous local pressure plastic deformation of the workpiece. Compared with the conventional rotary forging with a single roll, it has many outstanding advantages. Rotary forging with DSRs can form large diameter : thickness ratio discs.
The deformation of blades under complex loads of multiple working conditions reduces the energy conversion efficiency. To reduce the deviation of the blade shape in practical working conditions, a combination and optimization method of blade design schemes under multiple working conditions, based on the entropy weight vague sets, is proposed. The results show that the proposed design scheme has a smaller blade shape deviation than the traditional design scheme under multiple working conditions.
An innovative flapping wing micro aerial vehicle (FWMAV), forming a figure eight wingtip trajectory, which can achieve complex composite motions of flapping, twisting, and swinging is presented in this paper. Along with the design concept of reducing any possible weight and size, the aircraft was designed with classical and reliable mechanical components. Then, experiments were conducted to test the FWMAV aerodynamic efficiency with a complex figure eight wingtip trajectory.
Compared with the hydrostatic CVT used in the current cotton picker, the hydrostatic power split CVT has lower energy and fuel consumption. However, this kind of transmission usually has multiple speed regulation ranges, and the adjacent two ranges will produce impact and affect the driving comfort when shifting. In this study, the shift process of a hydrostatic power split CVT was analysed, and the results prove the feasibility of the application of this kind of CVT in the cotton picker.
The dynamic load-sharing characteristics of a face gear dual-power split transmission system (FGDPSTS) of an aircraft helicopter are studied. The effects of error, backlash, support clearance, spline clearance, torsional stiffness and support stiffness on dynamic load-sharing performance are analyzed. The load-sharing coefficient increases with the increase of the error, which provides a theoretical basis for the dynamic stability optimization design of the system.
An analytical method for programming piston displacements for constant flow rate piston pumps is presented. The results show that, with the given transition functions, cam profiles can be designed analytically with parameterized forms, and the maximum accelerations of the pistons are determined by the width of the transition domain and the rotational velocities of the cams, which will affect contact forces between cams and followers.
This study performs an analytical study of the modal and natural frequencies and the vibration types of each order of the gearbox housing structure of a planetary gear reducer (PGR). An optimal housing structure for a PGR with lower acoustic vibrations is designed, and a composite housing structure with damping vibration attenuation and acoustic absorption is proposed. The radiation acoustic characteristics without acoustic protection and damping materials are analyzed.
The center-point steering theory of a traditional tracked vehicle cannot be directly applied to a tracked omni-robot. In this study, for the three typical layout types, rectangular, hybrid, and centripetal, the steady center-point steering motion of a tracked omni-vehicle under skid conditions is analyzed and a correction model is investigated. The correction model can correct the angular velocity and time of the vehicle, as well as give the relationship between the design parameters.
In this paper, a high-rigidity screw-type tip-inserting mechanism with a good centering effect is designed. The structural characteristics and working principle of the inserting mechanism are introduced, the stiffness model of the new-type pipetting device is established and its stiffness and axial deformation are calculated. Finally, a multi-station high-throughput automatic pipette produced by a company was used as an example to optimize and improve it and conduct a prototype test.
This investigation is a further study on the consideration of the cutting edge radius of the cutter and the material of the workpiece based on the methods of finite element simulation and the micro end cutting experiment. The minimum undeformed chip thickness (MUCT) value increases with the increase of the cutting edge radius, no matter which process. In this study, the influence of important variables on MUCT is studied as much as possible to reflect a real application situation.
This paper presents an industrial robot-aided ultrasonic thickness measurement system to meet the needs of precise and efficient wall thickness measurement of large thin-walled parts. The hardware platform of the system is established with the designed reliable and contactless ultrasonic device integrated into an industrial robot. It was experimentally proven that the proposed method has a positive significance for improving the accuracy and efficiency of thickness measurement.
A method is developed for planar four-bar linkages to cope with the mixed synthesis of motion and path-generation problems. The developed method selects an optimal combination by using the conic filtering algorithm, which is based on the similar characteristics of the value and direction between the conic and coupler curves in a certain neighborhood. The selected combination is substituted into an equation system of motion synthesis to solve the parameters of the planar four-bar linkages.
To improve the control accuracy, dynamic and static characteristics of the system need to be tuned. In this paper, we use a glowworm algorithm with an improved adaptive step size to tune the parameters of a robust adaptive fuzzy controller. Finally, the workpieces of three different materials are cut with two different cutting methods. The study revealed that the surface roughness value is reduced by 20 %–32 %, which further verifies the effectiveness of the optimal controller’s parameters.