Wheel Mechanism Research Articles

Integrated Optimal Planning of Distribution Network With Geographical-Zone-Restricted Renewable Energy Sources

Recently, a lot of renewable energy sources have been integrated into the distribution network. In consideration of economy and construction feasibility, some renewable energy sources are required to be installed in specific areas. In this paper, a bi-layer distribution network planning optimization model that considers the geographical restrictions of the installation locations of the substation, pumped storage plant, photovoltaic (PV) and wind power, as well as the impact of operation on planning, is proposed. In the planning optimization layer, the optimal distribution network topology with minimal total cost is obtained. The locations of the renewable energy sources and the substation are determined by the particle swarm optimization (PSO), and then all the components are interconnected using the dynamic minimum spanning tree (DMST) method. In the operation optimization layer, the economic operation strategy of the hybrid energy system with uncertainty is obtained by the scenario-based stochastic optimal power flow (OPF). The forecast error of the uncertain variable is represented by the probability distribution function, and the roulette wheel mechanism (RWM) is used to generate the stochastic scenarios. A modified 103-bus system is used to test the effectiveness of the proposed method, and the simulation results show that the proposed method can effectively reduce the total cost of the distribution network.

Modular Two-Degree-of-Freedom Transformable Wheels Capable of Overcoming Obstacle

This study presents modular transformable wheels capable of overcoming obstacles. They can be used for indoor service robots or service platforms such as wheelchairs and baby carriages, which often move up and down on thresholds or on sidewalks. The structure of the wheel and transformation mechanism are introduced. The wheel has two built-in brushless DC (BLDC) motors. The BLDC motor is remodeled to add the gear box inside. These motors create a two-degree-of-freedom (2-DOF) transformation of the wheel. The 2-DOF mechanism is achieved by a 7-bar linkage with six rotational joints and one prismatic joint. A platform using the presented modular transformable wheels was used to experimentally verify the ability to climb up and down a staircase.

Modelling, simulation and experimental validation of wheel and arm locomotion based wall-climbing robot

AbstractThis article presents modelling, simulation, and development of a wall-climbing robot based on coupled wheel and arm-type locomotion mechanism. The developed robot consists of two mobile modules connected with a robot arm mechanism. The actuation of the robot arm is inspired by inchworm locomotion, particularly during wall-to-wall transition, obstacle avoidance, and uneven surface locomotion. Easiness in the interchanging of wheel to arm and vice versa makes the robot more effective compared to previously developed wall-climbing robots. The kinematic and dynamic model for the proposed coupled wheel and arm locomotion concept has been established. A combination of particle swarm optimization (PSO) and proportional, integral, derivatives (PID) feedback control algorithm has been developed using MATLAB to simulate the different cases of robot motions. The developed prototype of the wall-climbing robot is used to verify the coupled wheel and arm locomotion concept in various wall climbing scenarios. The simulation and experimental findings show good comparisons and validate the model-based design of the wall-climbing robot.

Polygonal wear mechanism of high-speed wheels based on full-size wheel-rail roller test rig

The polygonal wear of train wheels is common. It increases the wheel-rail interaction force drastically and adversely affects the safety and comfort of the train. The mechanism of the initiation and development of polygonal wear warrants further study. This study performed a high-speed rolling test based on the full-size wheel-rail roller test rig to reproduce the entire process of the generation and development of the polygonal wear on the tested wheelset of CL60 steel in the laboratory. The mechanism of the initiation and development of polygonal wear was analyzed using the test results, the bending resonance of wheelset was considered as an important cause of the polygonal wear in this paper. The basic condition for the polygonal wear formation and its high rate of development was verified. The evolution process of polygonal wear was studied in-depth, and the relationship between axle-box acceleration and polygonal wear was revealed. Effective countermeasures against the development of polygonal wear were proposed. Variable speed operation could mitigate the development of polygonal wear in this paper. The results obtained in this study may provide reference for the further study of the effective countermeasures against the development of polygonal wear.

Step-climbing wheel mechanism capable of reduction of swaying

Many mobile devices currently use wheels. Most of them have the problem that their mobility performance on level ground is hindered by steps. In addition, prior research on overcoming steps has focused on whether or not steps can be overcome, and has not considered swaying and vibration. Therefore, if such a wheel mechanism is applied, it is difficult to overcome a step with less burden on the passenger. Therefore, this study proposes an axle-moving wheel model that can reduce the force, vibration, and shock required to overcome a step. We will verify the usefulness of this model by applying it to the front wheel of a wheelchair, which is required to reduce shock and vibration.

ISHELL: a 1–5 micron R = 80,000 Immersion Grating Spectrograph for the NASA Infrared Telescope Facility

iSHELL is a 1.06–5.3 μm high spectral resolution spectrograph built for the 3.2 m NASA Infrared Telescope Facility (IRTF) on Maunakea, Hawaii. Dispersion is accomplished with a silicon immersion grating in order to keep the instrument small enough to be mounted at the Cassegrain focus of the telescope. The white pupil spectrograph produces resolving powers of up to about R ≡ λ/δλ = 80,000 (0.″375 slit). Cross-dispersing gratings mounted in a tiltable mechanism allow observers to select different wavelength ranges and, in combination with a slit wheel and Dekker mechanism, slit widths ranging from 0.″375 to 4.″0 and slit lengths ranging from 5″ to 25″. One Teledyne 2048 × 2048 HAWAII-2RG array is used in the spectrograph, and one Raytheon 512 × 512 Aladdin 2 array is used in a 1–5 μm slit viewer for object acquisition, guiding, and scientific imaging. iSHELL has been in productive regular use on IRTF since first light in 2016 September. In this paper we discuss details of the science case, design, construction and astronomical use of iSHELL.

Implementation of in-row weeding robot with novel wheel, assembly and wheel angle adjustment for slurry paddy field

In recent years, the demand on food product has been increasing. Paddy cultivation needs new weed controlling methods, since paddy cultivation supplies major food demands, also weeding in the paddy fields impacts the production considerably. Paddy fields are structured field which have plants in rows and columns with around one foot from each other under system of rice intensification (SRI) methods and paddy fields are slurry in nature. Autonomous in-row robot which moves on the planned path with weed remover, covering minimum two sides of the paddy plants will be ideal. Autonomous mobile robot needs the perfect wheel mechanism which will not disturb the rooted plants. Robotic solution adds no greenhouse gas, improves pollution index when replacing oil engine-based equipment. From study, the research gap on suitable wheel to fit for slurry field mini robot is found. In this paper, a new design and development of In-row mini mobile robot suitable to work autonomously in the slurry paddy field using novel wheel and wheel angle adjustment assembly are proposed. The screw wheel is designed using “Solidwork” 3D designing software, and printed using non-metallic 3D printer. The structure of the robot is designed and fabricated in the metal works. Optimization of wheel position to reach optimum turning angle is also achieved through field experiments. The optimum angle of wheel position was found to be around 35 degrees with error value of ± 2 degrees. It can be furthered investigated for different vehicle dynamics parameter.

Design and Dynamic Simulation Analysis of a Wheel–Track Composite Chassis Based on RecurDyn

The traditional chassis has the problems of low trafficability and poor stability under complex and changeable unstructured conditions. Thus, a wheel rail composite chassis is proposed. The chassis had a tracked travel mechanism at the front wheels and a wheeled travel mechanism at the rear wheels. This study presents the design, theoretical analysis and dynamic simulation analysis of the chassis. The maximum values of the passability of the wheel–track composite chassis that can be passed were calculated according to the relevant parameters. Furthermore, the chassis was modeled and simulated using RecurDyn to verify whether the values were reasonable. According to different values of the terrain, slope, vertical obstacle height and trench width, the change regularity of the track tension and driving torque of the chassis were obtained. The chassis is designed to improve the vehicle’s ability to operate under complex and diverse unstructured conditions.

Design of mechanical devices for the elderly to move and live alone

With the increasing aging of the population, the demand for elderly assistance machinery is increasing. By comparing the advantages and disadvantages of the existing elderly assistance devices and analyzing the daily activities and care needs of the elderly, this paper determines the main functions of the mechanical devices for the elderly to move around alone and proposes a general design scheme. Based on the overall design plan, the main mechanisms such as axillary support mechanism, sitting mechanism, posture adjustment mechanism and wheel mechanism were designed, and the operability and stability of the device were improved through the linkage of the variable cell mechanism. Virtual prototype modeling was carried out by solidworks to verify the rationality of the structure. The device not only has better function, but also has simpler structure and lower maintenance cost, which is more suitable for market demand.

Stochastic multi-objective optimal energy management of grid-connected unbalanced microgrids with renewable energy generation and plug-in electric vehicles

Microgrids (MGs) contribute to the integration of renewable energy-based distributed generation (DG) units and electric vehicles (EVs) in a smart, secure, sustainable, and economic fashion. However, the unbalanced nature of MGs along with the probabilistic nature of renewable energy, electricity prices, and EV demand complicate the energy management process. To overcome that challenge, a stochastic multi-objective optimization model for grid-connected unbalanced MGs is proposed here to minimize the total operational cost and the voltage deviation. The epsilon-constraint method and fuzzy satisfying approach are used to solve the multi-objective optimization problem and to obtain compromise solutions. Uncertainties are considered by employing the roulette wheel mechanism for generating scenarios regarding renewable energy generations, EV charging demands, electric loads, and electricity prices. In addition, to avoid adopting infeasible and impractical solutions, a three-phase power flow is integrated in the proposed model. The proposed method is assessed in a modified IEEE 34-bus test system consisting of EVs, battery systems, wind turbine units, photovoltaic units, and diesel generators. The results show the effectiveness and benefits of the proposed model for handling uncertainties while minimizing both operational cost and voltage deviation index and providing more realistic and reliable solutions that can be applied by MG operators.

DEVELOPMENT OF INTELLIGENT SELF-BALANCING E-BIKE USING MACHINE LEARNING

The self-driving autonomous cars is becoming an increasingly popular concept all around the world but the area of self-driving two wheelers is still under developed. For developing countries like India, two wheelers are affordable than cars for most of the population. The project aims at developing intelligent self-balancing bike using artificial intelligence because the major problem in developing an autonomous bike is in the area of balancing. Even though there are many working mechanisms available for self-balancing of bike, the implementation of AI will be an edge over others from the point of computational power requirement and the programming complexity incurred. A prototype of the bike was developed with reaction wheel mechanism for self-balancing. The mechanism was fully controlled by AI by preventing the need of explicit programming for balancing which was the earlier technique used in self-balancing bike. Reinforcement learning, a type of machine learning technique is adopted for this purpose. The policy gradient algorithm was used to make the bike learn by itself for balancing. Even though the AI algorithm worked well in the virtual environment (balancing a cart-pole) it fails in the real environment. (i.e. it fails to balance the bike). It is because of the noisy data from the sensor, which gives inaccurate information about the orientation of the bike. The noise in the data is due to the vibration of the body when the reaction wheel rotates. This could be solved if the AI is fed with accurate information about the orientation of the vehicle.

Learning an Optimal Operational Strategy for Service Life Extension of Gear Wheels with Double Deep Q Networks

One failure mechanism of gear wheels is pitting. If the gear wheel is case hardened, pitting degradation dominates normally at one tooth only. All the other teeth are still intact at the standardized end of life criterion of 4 % pitting area based on the total tooth area.
 Using an operational strategy that was developed at the Institute of Machine Components, the service life of gear wheels can be extended by a local stress reduction at the weakest tooth. This is accomplished by applying an adapted torque at the transmission input that shifts a minimum torque in the area of the pre-damaged, and thus, weakest tooth. Consequently, all remaining teeth with higher load bearing capacity are subjected to higher torque. Prerequisite for the described theoretical operational strategy is knowledge on pitting-size and -position. The detection of these properties in operation is not state of the art yet.
 In this work, only the gearbox vibration signal is known without explicit knowledge about the inside pitting. So the challenge is to determine the health for each individual tooth and to choose an optimal adapted torque based on this. This is especially difficult due to differing growth rates of pittings on one individual gear wheel. Hence, different pittings dominate over the service life, which results in the need of a continuous optimization of the torque control.
 Algorithms of Reinforcement Learning (RL) are particularly suitable for this challenge. In this branch of Machine Learning (ML), an agent interacts inside an environment and learns by getting rewards for taking actions at given states. In this study, the environment is a gearbox-simulation-model, the state is the current vibration signal, and the action is the chosen adapted torque. Thus, it is possible to let the algorithm learn the whole operational strategy, from online failure detection to an adapted torque at the transmission input.
 The results of this study show the theoretical feasibility of the operational strategy using Double Deep Q Networks as the RL Algorithm. The algorithm is able to learn a suitable reaction to pittings that increase linearly or progressively at an early stage and therefore delays their growth within the defined limits. Thus, the lifetime of the gearbox is extended while maintaining the same total power of the gearbox. As an outlook, the results will be examined for their sensitivity on several influencing factors in a further study. The wider view is to use this simulation on a test rig and validate the results.

A study of a flux switching linear generator with a novel speed amplified mechanism and its optimization for the maximum power output and minimum cogging force of wave energy conversion

A flux switching electromagnetic wave energy harvester with a novel speed amplified mechanism has been proposed and simulated. The novelty of the design is the relative speed of the translator with respect to the stator being doubled through a fixed pulley wheel mechanism. The output power was simulated by the ANSYS Maxwell module from input design parameters. The relationship between the input design parameters and target peak power output has been established through the simulation to understand the science. The sensitivity of the design parameters and their interactions has been studied through the Taguchi method (Design of Experiment) and response surface methodology (RSM). The design parameters of the stator and arrangement of the magnet configuration have been optimized for the maximum peak output power. The RSM model has been validated by the analysis of the variance method. The optimal results of the RSM model have been verified by the ANSYS simulation results. The RSM is proven to be a useful tool for design and optimization of the linear generator take-off unit. The cogging force has also been minimized by optimizing the dimensions of the feet on the stators using the RSM. The analysis and simulation methods have contributed to new knowledge of the flux switching electromagnetic wave energy harvester.

Design and Research of All-Terrain Wheel-Legged Robot.

Aiming at the crossing problem of complex terrain, to further improve the ability of obstacles crossing, this paper designs and develops an all-terrain wheel-legged hybrid robot (WLHR) with strong adaptability to the environment. According to the operation requirements in different road conditions, the robot adopts a wheel and leg compound structure, which can realize the transformation of wheel movement and leg movement to adjust its motion state. The straight and turning process of the robot is analyzed theoretically, the kinematics model is established and solved, and obstacle crossing analysis is carried out by establishing the mathematical model of front wheel obstacle crossing when the robot meets obstacles. To verify the analysis results, ADAMS software is used to simulate and analyze the process of robot running on the complex road surface and obstacles-crossing. Finally, a theoretical prototype is made to verify its feasibility. Theoretical analysis and experimental results show that the designed WLHR is feasible and has the stability of the wheeled mechanism and the higher obstacle crossing ability of the legged mechanism so that the robot can adapt to a variety of complex road conditions.

Research on an intelligent electric inspection robot

Due to the bad environment of electric power inspection, it is easy to cause physical injury to the inspectors. Besides, the heavy workload of inspection is easy to cause the omission of the wireman that leading to major accidents. In order to avoid the mistakes in the process of electric inspection, an intelligent robot for independent inspection instead of manual operation is proposed in this paper. Firstly, the overall configuration of the robot is designed, a four-wheel active driving wheeled mobile mechanism is adopted and the dual parallel camera with three degrees of freedom is carried to inspect the faults existing in the power equipment. Secondly, based on the nonholonomic constraints, the kinematics analysis of the robot is carried out, and the variation laws of the velocity and angular velocity are obtained. In addition, based on the theory of finite element analysis, the modal analysis of the key parts of the robot is carried out to avoid resonance when working to affect the inspection accuracy. Finally, the motion process of the robot in various environments is simulated to verify the correctness of the robot kinematics model and the rationality of the structure design. According to the simulation results, the robot can run stably in typical environments.

Discovery and Temperature Dependence of α-Fe2O3 in Oxide Film on Iron Bonded Wheel and Effect Mechanism of Temperature

Polishing of oxide film on ELID wheel surface has an important effect on grinding surface quality. First, electrochemical reaction of oxide film was researched, and transformation mechanism of component of oxide film under grinding temperature was proposed. The phase compositions, generation and transformation mechanism of the α-F2O3 in the oxide film was measured by XRD, XPS, FITR. The microstructure of oxide film was observed by using TEM. Researched results show, α-F2O3 in the oxide film have been found, the content and transformation of α-F2O3 are closely related to the grinding temperature. Iron oxide in oxide film is transformed into α-F2O3 with temperature gradually, and nano grain α-F2O3 with high purity, good crystal lattice, and grain size 10–80 nm is formed when grinding temperature is 600 °C. TEM analyzed shows, the grain in oxide film is spherality, and film structure is formed with multiple particles α-F2O3. The film structure reveals that polishing mechanism of oxide film isn’t independent act of single particle, but is cooperative behavior of multiple particles α-F2O3.

Collision Avoidance and Stability Study of a Self-Reconfigurable Drainage Robot.

The inspection and maintenance of drains with varying heights necessitates a drain mapping robot with trained labour to maintain community hygiene and prevent the spread of diseases. For adapting to level changes and navigating in the narrow confined environments of drains, we developed a self-configurable hybrid robot, named Tarantula-II. The platform is a quadruped robot with hybrid locomotion and the ability to reconfigure to achieve variable height and width. It has four legs, and each leg is made of linear actuators and modular rolling wheel mechanisms with bi-directional movement. The platform has a fuzzy logic system for collision avoidance of the side wall in the drain environment. During level shifting, the platform achieves stability by using the pitch angle as the feedback from the inertial measuring unit (IMU) mounted on the platform. This feedback helps to adjust the accurate height of the platform. In this paper, we describe the detailed mechanical design and system architecture, kinematic models, control architecture, and stability of the platform. We deployed the platform both in a lab setting and in a real-time drain environment to demonstrate the wall collision avoidance, stability, and level shifting capabilities of the platform.

Design and motion analysis of reconfigurable wheel-legged mobile robot

An adaptive wheel-legged shape reconfigurable mobile robot, based on a scissor-like mechanism, is proposed for an obstacle detecting and surmounting robot, moving on complex terrain. The robot can dynamically adjust its own shape, according to the environment, realizing a transformation of wheel shape into leg shape and vice versa. Each wheel-legged mechanism has one degree of freedom, which means that only the relative motion of the inner and outer discs is needed to achieve the transformation of the shape into a wheel or a leg. First, the force analysis of the conversion process of the wheel-legged mechanism is carried out, while the relationship between the driving torque and the friction factor in the non-conversion trigger stage and in the conversion trigger stage is obtained. The results showed that the shape conversion can be better realized by increasing the friction factor of the trigger point. Next, the kinematics analysis of the robot, including climbing the obstacles, stairs and gully, is carried out. The motion of the spokes tip is obtained, in order to derive the folding ratio and the surmountable obstacle height of the wheel-legged mechanism. The parameters of the wheel-legged structure are optimized, to obtain better stability and obstacle climbing ability. Finally, a dynamic simulation model is established by ADAMS, to verify the obstacle climbing performance and gait rationality of the robot, in addition to a prototype experiment. The results showed that the surmountable obstacle height of the robot is about 3.05 times the spoke radius. The robot has the stability of a traditional wheel mechanism and the obstacle surmount performance of a leg mechanism, making it more suitable for field reconnaissance and exploration missions.

Stochastic Multi-objective Short-term Hydro-thermal Self-scheduling in Joint Energy and Reserve Markets Considering Wind-Photovoltaic Uncertainty and Small Hydro Units

In this paper, a stochastic multi-objective structure is introduced in joint energy and reserve market to allow energy generation companies (GENCOs) participating in the short-term hydro-thermal self-scheduling with wind, photovoltaic uncertainty and small-hydro units. In addition, uncertainties including energy price, spinning and non-spinning reserve prices as well as the uncertainty of renewable energy resources such as output power of the wind, PV and small-hydro power plants are mentioned. One pivotal feature of this study is that two methods are used to generate stochastic multi-objective scenarios, namely lattice monte carlo simulation and roulette wheel mechanism. After that, the main purpose of the study is described, i.e., making GENCOs able to achieve the maximum profit and the minimum emission by using a multi-objective function considering a stochastic process. To reach this aim, the mixed integer programming which includes a set of multi stage deterministic scenarios is employed. However, some special cases should be introduced in the formulation structure of the presented scheduling regarding hydro-thermal units to make the SMO-HTSS problem with wind, PV and SH units alike real time modeling. Since optimal Pareto solutions are produced in this method, one can allude to the application of the e-constraint method. Nevertheless, in order to select one of the most appropriate solutions among Pareto solutions obtained, the utilization of fuzzy method has been presented. In the end, some tests are carried out on an IEEE 118-bus test system to verify the accuracy and validity of the proposed method.

A novel traveling wave piezoelectric actuated wheeled robot: design, theoretical analysis, and experimental investigation

Traditional traveling wave robots have strict requirements on the operating interface due to the fact that they usually only work on smooth and flat surfaces, holding the disadvantages of poor load capacity and complex driving mode, and limiting their application range. In order to overcome the above problems, a novel traveling wave piezoelectric actuated wheeled robot is proposed in this study. The robot is composed of a bonded-type piezoelectric actuator and wheel mechanisms. Rotating traveling wave can be produced in the annular parts of the piezoelectric actuator to drive the wheel mechanisms. In order to study the dynamic characteristics of the piezoelectric actuator, an electromechanical coupling model is developed by using the transfer matrix method. Then the prototype of the piezoelectric actuator is fabricated and assembled, and its vibration characteristics are measured to confirm the feasibility of the developed transfer matrix model. Finally, performance evaluation investigations of the proposed traveling wave piezoelectric actuated wheeled robot are conducted. Under the excitation voltages of 350 V pp and the phase difference of 90°, the robot prototype achieved a step climbing angle of 75°, a maximum no-load velocity of 136.8 mm s−1, and a maximum payload of 320 g. The proposed traveling wave piezoelectric actuated wheeled robot presents expected terrain adaptability and obstacle climbing capability.