Adaptive fuzzy design of a rope attitude adjustment system

The attitude adjustment of rope system faces the challenging due to the difficulty in obtaining accurate three-dimensional(3D)mathematical model and solving by traditional methods.A set of adjustment systems is designed and used to investigate the automatic control for level or preset attitude adjustment of unknown weights and eccentric loads.The system principle and characteristics are analyzed.The 3D model is decomposed into two two-dimensional(2D)subsystems,and an adaptive fuzzy controller based on BP neural network and least squares(LSE)is designed.The simulation experiment uses MATLAB to train the level-adjustment data for testing algorithm,and a small load is used to verify the effectiveness of the system.The experimental results show that precise attitude adjustment can be achieved within the system load range,and the response speed is fast.This adjustment method provides a fast and effective method for precise adjustment of the load attitude.

Design and experiment analysis of the small maize harvester with attitude adjustment in the hilly and mountainous areas of China

To solve the problem of small planting plots and large sloping land for mechanized maize harvesting in China hilly and mountainous areas,a small maize harvester with attitude adjustment was designed to realize maize snapping,peeling,straw crushing and attitude adjusting at on time in this study.The basic structure and working principle of the small maize harvester were described,and the key components were designed as follows.The maize snapping device adopted the combination form of maize snapping plates and straw pulling rollers,and the gap of the straw pulling rollers can be adjusted to adapt to different maize varieties.Two pairs of peeling rollers formed a groove arrangement to improve peeling rate and reduced ear grain loss.The pressure feeding device mainly comprised drive chain and three grade pressure feeding rollers to increase the friction between ears and the peeling rollers,and help ears slide.The attitude adjustment advice was designed according to the high point stationary pursuit leveling method.When the attitude angle of the rack approached 0,the small maize harvester reached the level state.The actual range of attitude adjustment was obtained and the accuracy of static attitude adjustment was verified through attitude adjustment test.The influencing factors of ear loss rate and bract peeling rate were determined by orthogonal test,including the rotational speed of straw pulling rollers,peeling rollers and pressure feeding rollers.The mathematical regression model between the experimental factors and indicators was established by using Design Expert,and through the analysis variance to verify the significance of the evaluation indicators,the best combination of operation parameters was determined that the rotational speed of straw pulling rollers,peeling rollers and pressure feeding rollers were 1440 r/min,1535 r/min and 406 r/min.Under the optimal combination of the operation parameters,the ear loss rate and bract peeling rate were 1.33%and 93.98%.The design indicators of the small maize harvester can meet the relevant national standards,and can satisfy the need of maize mechanized harvesting in China hilly and mountainous areas.

Singularity Robust Path Planning for Real Time Base Attitude Adjustment of Free-floating Space Robot

This paper presents a singularity robust path planning for space manipulator to achieve base （satellite） attitude adjustment and end-effector task. The base attitude adjustment by the movement of manipulator will save propellant compared with conventional attitude control system. A task-priority reaction null-space control method is applied to achieve the primary task of adjusting attitude and secondary task of accomplishing end-effector task. Furthermore, the algorithm singularity is eliminated in the proposed algorithm compared with conventional reaction null-space algorithm. And the singular value filtering decomposition is introduced to dispose the dynamic singularity, the unit quaternion is also introduced to overcome representation singularity. Hence, a singularity robust path planning algorithm of space robot for base attitude adjustment is derived. A real time simulation system of the space robot under Linux/RTAl （realtime application interface） is developed to verify and test the feasibility and reliability of the method. The experimental results demonstrate the feasibility of online base attitude adjustment of space robot by the proposed algorithm.

Design and physical model experiment of an attitude adjustment device for a crawler tractor in hilly and mountainous regions

To address the problems of difficult leveling and poor stability of hill crawler tractors,an attitude adjustment device based on a parallel four-bar mechanism was designed,and the mechanical reasons for the sideslip instability of hill crawler tractors were analyzed.On this basis,a posture adjustment mechanism based on a parallel four-bar mechanism was proposed,and the structure of the complete attitude adjustment device was designed.To ensure that this device meets the strength requirements during operation,a mechanical analysis of the key components(active rocker and slave rocker)was carried out to accommodate the load during leveling.Based on ANSYS software,a finite element simulation analysis was used to determine the maximum stress position of the active and slave rockers.Finally,to verify the accuracy of the above simulation analysis results and determine the influence rules of the lateral slope angle,longitudinal slope angle and loading quality on the abovementioned maximum stress,a physical model test bench of the attitude adjustment device was built.An orthogonal regression experiment was carried out with the maximum stresses of the active and slave rockers as the test indices.The experimental data were analyzed by Design-Expert 10 software,and the results show that the order of the primary and secondary factors influencing the maximum stress of the active rocker was the loading mass,lateral slope angle and longitudinal slope angle.The order of the factors influencing the maximum stress of the slave rocker was the longitudinal slope angle,lateral slope angle and loading mass.The active and slave rockers meet the strength requirements.This work provides technical support for the production of hill crawler tractor physical prototypes.

Design of deep-water omnidirectional spirit level

Attitude adjustment is a key link in the installation process of underwater facilities in deep water.To solve this problem,an omnidirectional spirit level for deep water was developed.The sealing principle of the spirit level and the principle of deep-water pressure resistance are analyzed,and the threaded connection strength is checked.The mechanical simulation verifies that the spirit level can withstand the pressure of 2000 m water depth,and the water pressure test is carried out for 30 min in a 20 MPa hyperbaric chamber.After the experiment is completed,the appearance of the spirit level is intact and there is no leakage.The experiment results show that the deep-water omnidirectional spirit level can be used in the deep sea within 2000 m.

Study on Ship Automatic Berthing System with Mooring Lines

This study describes an automatic berthing system with mooring lines. It is designed to be berthed by using mooring device on the upper deck of a ship. It is to berth once maintaining parallel with the quay by controlling both forward and aft breast lines. Berthing method is used through length adjustment of mooring lines connected between ship and quay by controlling the angular velocity and the torque of hydraulic motor in mooring device. The study is conducted under three changing conditions of draft, such as even-keel, rise of the gravity center and trim to stern. Variables affecting berthing stability are determined based on the control performance of each condition. Bond graphs method is used to model the system. Controller is designed as PID control method of reference-model algorithm. The control program is composed of synchronous control system based on the equations derived with the numerical analysis. The tank test is conducted to verify the usefulness of the control program.

Prototype Design and Experimental Study on Locust Air-Posture Righting

Locust has the capacity to maintain a righting posture and glide through attitude adjustment after leaping. A prototype inspired by the dynamic mechanism of attitude adjustment of locusts was developed. The prototype consists of a pair of wings driven by a four-bar mechanism, and a 2 Degree of Freedom （DOF） tail to imitate the movement of the locust abdomen. The power source, microcontroller, wireless data transmission module, and attitude sensors are contained in the fuselage. Experiments imitating the flight of locust were conducted to determine the mechanism of locust Subsequent Attitude Adjustment （SAA）. The tethered prototype was driven by the movement of the tail and the flapping of the wings. Results show that the pitch and yaw of the tail, and the asymmetric action of the flapping wings significantly influence the posture of the prototype. These findings suggest that both the wiggling abdomen and flapping wings contribute to the locust SAA in the air. This research lays the groundwork and technical support for the probable design and development of practical jumping robots with attitude adjustment function.