To accurately and efficiently analyze the magnetic and dynamic characteristics of multishaft double ring-plate magnetic gears (MDRMGs), improve the working conditions of CPMG arm bearings, and extend their service life, a multishaft double-ring magnetic gear transmission structure was designed by combining magnetic gears with mechanical ring-plate gears.

A magnetic field unit classification method was proposed, and then a mathematical model for air-gap magnetic field and static torque was established, which was efficient and took the end leakage magnetic effect into account. Meanwhile, based on the Riccati transfer matrix method, a dynamic model of the eccentric shaft rotor system of MDRMG was constructed.

A comparison between the magnetic field unit classification method and the finite element method shows that the results of magnetic flux density and magnetic force obtained by the two methods are highly consistent, but the calculation time of the magnetic field unit classification method is shorter. The analysis also reveals that changes in the ring-plate spacing affect the classification calculation of magnetic field units and the lumped parameters in the dynamic model, the static magnetic torque of MDRMG increases with the increase of ring-plate spacing, while the critical speed of the eccentric shaft decreases as the ring-plate spacing increases. The magnetic field unit classification method can efficiently and accurately analyze the air-gap magnetic field and torque characteristics of MDRMG. In addition, the ring-plate spacing has a certain impact on the magnetic field and dynamic performance of MDRMGs.

To address the longitudinal vibration of long-distance belt conveyors during starting, the dynamic equations of the belt conveyor were established based on the analysis of the viscoelastic properties of the conveyor belt. Taking a practical long-distance belt conveyor as an example, a dynamic simulation model was constructed using AMESim software to study the starting acceleration curve and loading time.

The effects of common starting curves on the dynamic tension of the conveyor belt were analyzed, and a new combined starting curve (sine+parabolic) was proposed. The curve was optimized by introducing a creep phase and adjusting the pre-starting speed. The tension variations under different loading times were then analyzed.

The results show that the optimized sine and parabolic starting curve reduces the maximum tension of the conveyor belt by 5.8% compared with the commonly used sine acceleration curve. Furthermore, loading materials after stable operation effectively reduces the tension impact and extends the service life of the conveyor belt.

To address the problem that pure rolling bevel gears are prone to angular velocity mutation, vibration, and noise excitation under the influence of mounting errors, a tooth surface design method with low sensitivity to mounting errors was proposed.

Firstly, based on the influence of installation errors on angular velocity, the transmission error curve was preset as a parabolic type. Secondly, the theoretical tooth surface of the pinion was modified using the preset transmission error curve to establish a mathematical model of the target tooth surface. Finally, a 3D solid model of the modified bevel gear was constructed, and tooth contact analysis was performed.

The results show that the derived transmission error curve is consistent with the preset curve, validating the effectiveness of the modification. The actual meshing points of the optimized tooth surface deviate from the edges, and the overall contact area centers on the tooth surface, effectively avoiding edge contact and stress concentration.

Contact fatigue failure is the primary failure mode for gears operating under extreme conditions such as high speed, heavy duty, and high temperature. It has become a significant technical bottleneck limiting the development of aviation equipment toward higher reliability, longer life, and higher power density. Predicting contact fatigue life is now a critical focus of both engineering and academic research. The quantitative prediction research of gear contact fatigue life was carried out.

Firstly, over 400 rolling contact fatigue specimens made from 9310 aviation gear steel were prepared and subjected to more than 5 000 hours of fatigue testing. The investigation examined the effects of service conditions, such as contact stress and slip rate, as well as surface integrity states created by over ten processes including carburizing grinding, shot peening, fine particle peening, and rolling finishing, on rolling contact fatigue life. Secondly, the Lundberg-Palmgren （LP） theory was modified using multiple linear regression methods, resulting in an LP rolling contact fatigue life prediction formula based on service conditions and surface integrity parameters.

It is found that increasing the slip rate from 10% to 30% reduces the fatigue life at a contact stress of 3 000 MPa by 52.6%, from 2.28×10⁶ r to 1.08×10⁶ r. Additionally, when the contact stress is 3 000 MPa and the slip rate is 20%, dual shot peening significantly improves fatigue life, increasing it by 113.8% from 1.52×10⁶ r in the carburizing grinding state to 3.25×10⁶ r. The derived LP contact fatigue life prediction formula, considering service conditions and surface integrity, demonstrates an error margin within twice dispersion band, thus meeting engineering application requirements.

To solve the problem of no direct mechanical or hydraulic connection between the brake actuator and the brake pedal in an electronic mechanical braking system, leading to no feedback of road feel, a brake pedal feeling simulator was proposed based on magnetorheological dampers.

Ansys/Maxwell and Matlab/Simulink were used as the platform. The structural design of the sinking brake pedal feeling simulator, the structural design of magnetorheological damper, magnetic circuit analysis and electromagnetic simulation were carried out respectively, and the simulation analysis of traditional proportional-integral-derivative (PID) and fuzzy adaptive PID control under different working conditions of the whole system was compared.

The simulation results show that the brake pedal feeling simulator can track the characteristic curve of the traditional pedal well under different working conditions and has wide applicability. Compared with the traditional PID control effect, the fuzzy adaptive PID control has higher control precision and smaller control error, and has good application prospects.

To address the core problems of traditional magnetic tile-type magnetic wheels in the application of boiler wall-climbing robots, such as unclear magnetic field distribution, redundant safety factors of empirical formulas, low magnet utilization rate, and excessive weight, a magnetic tile arrangement scheme was identified with better magnetic attraction in the N-S alternating arrangement under the same volume and mass constraints. The differences in magnetic field distribution and magnetic attraction force magnitude when the magnetic wheel pressed against three versus two boiler water-cooled wall tubes were also clarified.

Taking a water-cooled wall inspection robot for thermal power plant boilers as an example, four magnetic wheel models with the same external dimensions but different magnet arrangement modes were established. Using Maxwell software, simulation analysis of the magnetic attraction force of these four magnetic wheels with different structures was conducted at a distance of 2 mm from the water-cooled wall tubes.

The results show that the adsorption force of the magnetic wheel on the water-cooled wall tube is 5%-20% greater when adsorbed at the joint of the magnetic tiles than at the middle of the magnetic tiles. When adsorbed at the middle of the magnetic tiles, regardless of whether the magnetic wheel presses against three or two wall tubes, the magnetic wheel with the 4-magnetic-tile arrangement exhibits the maximum attraction. Additionally, the adsorption force when pressing against three water-cooled wall tubes is approximately 10%-20% greater than that when pressing against two tubes.

In order to increase the depth of planting seedlings and reduce the width of transplanting holes, so as to improve the uprightness of rice pot seedlings after transplanting, the comprehensive design and test research of the transplanting mechanism based on the belt-shaped transplanting trajectory were carried out.

Firstly, a belt-shaped transplanting trajectory that can reduce the width of the hole was proposed, and the posture analysis of 10 key posture points on the transplanting trajectory was conducted according to the parameters of the transplanting mechanism and the requirements of motion design. Secondly, the seven-tooth non-circular gear planetary gear train transplanting mechanism was simplified into a planar 2R open chain mechanism, and a mechanism mathematical model based on the belt-shaped transplanting trajectory was constructed using the multi-position motion synthesis theory. Then, the objective function of the minimum change of the length of the planet carrier was established, and the App Design module of Matlab software was used to develop the multi-position motion comprehensive solution software for the rice pot seedling transplanting mechanism based on the genetic algorithm, and the optimal solution set of the key parameters of the transplanting mechanism was obtained. Finally, a simulation on the kinematic characteristics of the transplanting mechanism was carried out using Adams software, and a test prototype was fabricated to conduct the test research on field transplanting.

The simulation results show that the transplanting mechanism has the characteristic of quick return, and all the parameters and kinematic characteristics of the mechanism meet the design requirements, where the planting depth and transplanting hole width are 22.19 mm and 9.78 mm, respectively, which represent increases of 41.9% and decreases of 27.9% respectively compared to the corresponding value in relevant literature. The results of field test show that the average planting depth of rice pot seedlings is 22.84 mm, the average hole width is 10.37 mm, the excellent rate of verticality is 93.3%, and the transplanting effect is satisfactory.

Existing research on flexible hinges corresponds to complex expressions for flexibility and rotational accuracy calculations. To address this issue, a new type of catenary flexure hinge was designed, and a method for establishing the hinge’s compliance and rotational accuracy model by approximating arc segments with straight-line segments was proposed.

Firstly, by defining the flexure hinge as a series combination of tapered and expanded sections, the curve in the tapered segment was divided into several arc segments, and the curve segments were approximated with straight segments. Based on the Castigliano’s second theorem, a method by calculating the flexibility of the tapered section and then establishing the hinge flexibility and rotational accuracy model through matrix operations was established. Secondly, using specific examples, the derived formula, literature formulas, and the finite element method were employed for calculations. When the curve segment was finely divided, the calculation results align well, thereby verifying the formula’s correctness. Thirdly, the influence of structural parameters on the flexibility, rotation accuracy, and flexibility-accuracy ratio of catenary flexure hinges was analyzed. Finally, the bending flexibility and flexibility-accuracy ratio of the catenary, conic, and their hybrid hinges were analyzed with the same structural parameters.

The results show that a single parameter has a negative correlation with flexibility and rotation accuracy of the catenary hinge, and reducing the minimum thickness is the best way to improve flexibility. Under the same structural parameters, the flexibility and flexibility-accuracy ratio of the catenary hinge is between parabolic and circular shapes. Choosing a hybrid hinge with a section of high flexibility for the tapered section and a section of low flexibility for the expanded section allows for a balance between flexibility and motion accuracy.The greater the difference in flexibility, the better the flexibility-accuracy ratio.

The wave generator, as the driving component, has its profile curve directly affecting the deformation and stress distribution of the flexible wheel. To reduce the stress on the flexible wheel and improve its fatigue performance, a design method for a three-term cosine cam wave generator was proposed.

The profile curve of the three-term cosine wave generator was composed of a constant term, represented by the base circle radius, and three cosine terms superimposed. By using the curvature variation coefficient at the major axis, the correction factor at the minor axis, and the clearance of the flexible bearing as variable parameters, the influence of these parameters on the performance of the wave generator was analyzed, and the optimization of a specific harmonic reducer model was validated. Finite element analysis was performed on the flexible wheel structure after incorporating the new cam structure under expansion, no-load, and loading conditions, and comparisons were made with the pre-optimized structure to analyze the stress distribution on the flexible wheel.

The finite element results indicate that, compared to the traditional cosine wave generator, the flexible wheel under the three-term cosine wave generator exhibits superior stress performance under various working conditions and achieves longer fatigue life.

For slotted disk magnetic couplers, the slotted conductor disk complicates the magnetic circuit during operation, increasing the difficulty of calculating electromagnetic torque. A reliable electromagnetic torque prediction model was established, and its torque characteristics were studied.

A 18-pole 16-slot disk magnetic coupler was studied. Firstly, via the equivalent magnetic circuit method, induced eddy currents from adjacent and self-magnetic circuits were introduced as a branch into a new model. Considering 3D end effects and combining Ampere's and Kirchhoff's laws, air gap flux and output torque expressions were derived. Secondly, the coupler was simulated and analyzed by the finite element simulation software, obtaining distributions of air gap magnetic field and eddy currents, and torque variations with air gap thickness and speed difference under adjacent eddy current influence. Finally, a test platform was established to verify theoretical and simulation results.

The results show that the results of theoretical calculation, finite element simulation and test are basically consistent. The proposed theoretical model has high accuracy, providing a reliable prediction model for studying the torque performance of such couplers.