Steering mechanical analysis for lunar rover wheel

Facing the requirement of establishing a steering mechanical model for the wheel configuration design,selection of steering motors, dynamic analysis and simulation of the lunar rover, shear force beneaththe steering wheel, bulldozing resistance acting on steering wheel rims and side surfaces respectively areconducted on the basis of the wheel-loose soil interaction. The quantitative relation between steering resistancemoment (SRM) and steering radius, dimension of the wheel, soil parameters is established. Tovalidate the model, a single-wheel test bed is employed to test the steering performance of a wheel with0.15735m radius and 0.165m width when the steering radius is 0.00m, 0.04m, 0.08m, 0.12m and0.16m, respectively. The SRM is approached asymptotically with the increasing steering angle and almostproportional to the steering radius. The theoretical results of SRM are compact with the experimental results,which shows that the steering model can predict the experimental results well.

Research on Steering Resistance Moment of Wheel Loader

The wheel loader as the research object in present article,its steering mechanism is analyzed for the relationship between the steering cylinder displacement and the steering angle,which means,the relationship between the arm of steering resistance moment and the steering angle.In addition,the relationship between the in-situ steering resistance moment and the wheel angle is also be analyzed by integrating the interaction between the tire and the ground.The Matlab will help to build the mathematical modeling for verification.

The Recent Technological Development of Intelligent Mining in China

In the last five years, China has seen the technological development of intelligent mining and the application of the longwall automation technology developed by the Longwall Automation Steering Committee. This paper summarizes this great achievement, which occurred during the 12th Five-Year Plan （2011-2015）, and which included the development of a set of intelligent equipment for hydraulic-powered supports, information transfers, dynamic decision-making, performance coordination, and the achievement of a high level of reliability despite difficult conditions. Within China, the intelligent system of a set of hydraulic-powered supports was completed, with our own intellectual property rights. An intelligent mining model was developed that permitted unmanned operation and single-person inspection on the work face. With these technologies, the number of miners on the work face can now be significantly reduced. Miners are only required to monitor mining machines on the roadway or at the surface control center, since intelligent mining can be applied to extract middle-thick or thick coal seams. As a result, miners＇ safety has been improved. Finally, this Darter discusses theprospects and challenges of intelligent mining over the next ten years.

Design and Research of a Portable Tool for Assisting Elderly People Walking

Based on the serious aging of our country′s population,starting from the impact on the quality of life of the elderly,this paper first analyzes the factors affecting the lives of the elderly,and makes predictions based on my country′s elderly care industry market.After research,a portable tool for assisting elderly people walking is designed,in which electric drive,steering mechanism and seat functions are added by ordinary auxiliary walking tools.Users can sit down and ride when they are tired,mainly including seats and walking functions.The characteristics of its users and various influencing factors are analyzed.The research results can guide the solution of the current portable tools that assist the elderly in walking.

Beam steering application for W-band data links with moving targets in 5G wireless networks

Abstract:Ubiquitous broadband Internet access is one of the major goals of the next generation of wireless communications.However,there are still some locations where this is diffcult to achieve.This is the case on moving vehicles and,particularly,on trains.Among the possible solutions to this problem,RoF(Radio-over-Fiber)architectures have been proposed as low-latency,cost-e ective candidates.Two elements are introduced to extend the RoF approach.First,the carrier frequency is raised into the W-band(75-110 GHz)to increase the available capacity.Second,a mechanical beam-steering solution based on a Stewart platform is adopted for the transmitter antenna to allow it to follow a moving receiver along a known path,thereby enhancing the coverage area.The performance of a system transmitting a 2.5 Gbit/s non-return-to-zero signal generated by photonic up-conversion over a wireless link is evaluated in terms of real-time BER(Bit Error Rate)measurements.The receiver is situated in di erent positions,and the orientation of the transmitter is changed accordingly.Values below the forward error correction limit for 7%overhead are obtained over a range of 60 cm around a center point situated 2 m away from the transmitter.

Design and optimization of an automatic hydraulic steer-by-wire system for an agricultural chassis

To meet the requirements of fast steering at low vehicle speed and slow steering at high vehicle speed,the automatic steering of agricultural chassis must control both the wheel steering angle and the steering angle’s angular speed.This study applied hydraulic steer-by-wire technology to the automatic steering control of agricultural chassis.First,the transmission mechanism of the designed steering system was optimized.According to the rule of least squares,aiming at the minimum sum of squares of errors between 10 ideal outer wheel angles and real outer wheel angles,the optimal solution of hole spacing on both sides of the steering hydraulic cylinder piston rod was 925 mm.The outer wheel angle error of the optimized steering mechanism throughout the steering stroke was less than 0.15°.Additionally,a hydraulic steer-by-wire system was developed,and the parameters of its critical components were calculated.Then,the compound control strategy of the steering cylinder piston rod displacement and moving speed was formulated for this automatic steering system.The entire control system included a valve control signal calculation model,an initial velocity calculation model,a correction velocity calculation model,and an attenuation velocity calculation model,and the formulae of each model were deduced.Based on the optimized parameters and the developed control strategy,a simulation model was built in AMESim,and simulation results showed that the proposed control strategy could achieve simultaneous controls of piston rod displacement and speed at different vehicle speeds and loads.The horizontal and vertical displacements of the right wheel center were plotted for typical vehicle speeds and steering commands.The results of this study provided a new idea for the application of hydraulic steer-by-wire technology in the automatic steering of agricultural chassis.