One-way Bearings Research Articles

A hybrid wind and rainwater energy harvesting system for applications in sea-crossing bridges

As one of the essential types of clean energy, renewable energy has great potential to achieve the self-powered of wireless sensor. The health of the bridge depends mainly on the lifetime of the sensor. Therefore, it is of great significance to use renewable energy to achieve self-powered application of bridges. In this paper, a hybrid wind energy and rainwater energy harvester (WEREH) system for a self-powered sea-crossing bridge is presented. The proposed WEREH is installed on the drainpipe on the pier of the sea-crossing bridge. The system mainly includes three modules: energy collection module, energy conversion module, and energy storage module. The energy collection module is composed of S-rotor and water wheel. The energy conversion module is made up of a PVDF film array and magnet array. Electric energy can be obtained by the methods in which the PVDF films strike the adjustable plate and the changing magnetic field excites the coil. When only windy weather or only rainy weather is available, the S-rotor and water wheel are used to collect wind energy or rainwater energy, respectively. When it is windy and rainy mixed weather, the energy conversion module can keep working via one-way bearings. What is more, the S-rotor and water wheel can be flexibly combined with the energy conversion module to collect wind energy and rain energy, respectively. Finally, the power storage module stores the electricity by supercapacitors and the electric energy will be used to supply power for the low-power sensor of the sea-crossing bridge. Both simulations and experiments are performed to validate the feasibility and suitability of the system. Experimental results show that maximum output power can reach 2196.7 μWat the wind speed of 12 m/s and 245.76 μWat the flow rate of 18 L/min. Under the same condition, the maximum electric energy of the WEREH can reach 8659.76 μJin windy weather and 811.35 μJin rainy weather in a sweep process (6s). According to potential energy analysis, the annual electricity generated by each WEREH device can supply power for a displacement sensor (KTC1/LWH) for at least 239.95 days and a low-power temperature sensor (Si705x) for 254809.18 days at most.

Scavenging energy from wind-induced power transmission line vibration using an omnidirectional harvester in smart grids

Wind-induced power transmission line vibration is harmful to smart grids, and electronic devices that monitor the status of power lines require uninterrupted energy. Scavenging energy from wind-induced transmission line vibration to power these electronic devices is a feasible solution to these issues. In this study, an omnidirectional energy harvester was proposed, analyzed, fabricated, and tested. The harvester comprises a flexible rope, a one-way bearing, a three-phase direct current motor, and a spiral spring. One end of the flexible rope is attached to a power line and follows the disordered movement of the vibration, making it possible for the harvester to scavenge energy from all directions. The one-way bearing and spiral spring enable the harvester to scavenge random vibration energy. A theoretical analysis was carried out to determine the factors that would influence the energy harvester’s performance. The harvester was then fabricated and experiments were conducted. The simulation and experimental results correlated well. The maximum output voltage and output power of the harvester were 10 V (peak voltage) and 41.6 mW, respectively. The harvested energy can power a monitoring device for more than 1440 s. It can also power a temperature/humidity sensor, which can detect the status of the power line effectively. The proposed energy harvester can be used in smart grids for damping power line vibrations and powering electronic devices simultaneously.

Effect of the Utilizing Savonius Machine as Auxiliary Starting Device on the Performance of Darrieus Machine

In the present study, the two installation methods in combining Darrieus machine to Savonius machine were applied. First, Savonius machine was directly mounted to the main shaft of Darrieus machine and another one it was mounted to the main shaft via one-way bearing. The result shows that the self-starting ability of Darrieus machine could increase of about 60% by combining it with drag device such as Savonius machine. However, the net power extracted by this combination is significantly decrease. In the combination of Darrieus-Savonius machine where the Savonius was directly mounted on the main shaft without one-way bearing gives power reduction 53%, while in the combination of Darrieus-Savonius machine where the Savonius was mounted on the main shaft with one-way bearing gives power reduction of about 29%. Savonius machine mounted to the main shaft via one-way bearing gives relatively lower impact in power extraction reducing of Darrieus machine instead of Savonius was directly mounted to the main shaft without one-way bearing. As conclusion that the combination of Darrieus-Savonius machines should be addressed to improve the starting ability only, it should not be addressed to improve the power extraction capability of Darrieus machine.

A portable renewable wind energy harvesting system integrated S-rotor and H-rotor for self-powered applications in high-speed railway tunnels

The operation safety of high-speed railways has received great concern globally in recent years. The power supply of the electronic monitoring devices alongside high-speed railway tunnels and their maintenance are becoming increasingly important. In this paper, a portable renewable wind energy harvesting system integrated with an S-rotor and H-rotor has been designed to provide electricity to the monitoring sensors alongside railway tunnels in remote areas with shortages in the electricity supply. The proposed renewable wind energy harvesting system can harvest the wind energy inside the tunnel and convert it into electricity for self-powered applications. The renewable wind energy harvesting system scheme mainly consists of three components: a portable wind harvester mechanism, a generator module and a power storage module. The S-rotor and H-rotor are integrated as the wind harvester mechanisms in this system. The S-rotor harvests natural wind energy, and the H-rotor harvests piston wind energy when a high-speed train passes through the tunnel. Meanwhile, the S-rotor and H-rotor rotate the generator module separately through the one-way bearing. Finally, the supercapacitors in the power storage module are used to store the electrical energy. Experiments were conducted to study the performance of the system. A maximum electrical power output of 107.76 mW and a maximum efficiency of 23.2% are demonstrated in the test. The experimental data indicate that the wind energy harvesting system is beneficial and is a promising method to generate energy used for renewable self-powered applications in high-speed railway tunnels.

Design and Treadmill Test of a Broadband Energy Harvesting Backpack With a Mechanical Motion Rectifier

The energy harvesting backpack that converts the kinetic energy produced by the vertical oscillatory motion of suspended loads to electricity during normal walking is a promising solution to fulfill the ever-rising need of electrical power for the use of electronic devices in civilians and military. An energy harvesting backpack that is based on mechanical motion rectification (MMR) is developed in this paper. Unlike the conventional rack-pinion mechanism used in the conventional energy harvesting backpacks, the rack-pinion mechanism used in the MMR backpack has two pinions that are mounted on a generator shaft via two one-way bearings in a way that the bidirectional oscillatory motion of the suspended load is converted into unidirectional rotation of the generator. Due to engagement and disengagement between the pinions and the generator shaft, the MMR backpack has broader bandwidths than the conventional energy harvesting backpacks; thus, the electrical power generated is less sensitive to change in walking speed. Two male subjects were recruited to test the MMR backpack and its non-MMR counterpart at three different walking speeds. For both subjects, the MMR backpack for most of the time generated more power than the non-MMR counterpart. When compared with literature, the MMR backpack had nearly sixfold improvement in bandwidth. Finally, the MMR backpack generated nearly 3.3 W of electrical power with a 13.6 kg load and showed nearly two- to tenfold increases in specific power when compared with a conventional energy harvesting backpack.

Design and experimental evaluation of yoked hand-clutching for a lever drive chair

Lever-drive wheelchairs lower physical strain but are less maneuverable than push-rim wheelchairs. Here, we study a possible solution in which the user simultaneously actuates clutches mounted between the levers and wheels each stroke via a clutch handle attached to one lever; this solution is of particular interest for user groups with only one functional hand. First, to demonstrate maneuverability, we show how this “yoked clutch” allows an experienced user to maneuver a constrained space. Then, we compared the difficulty of learning a yoked clutch chair to a conventional lever-drive transmission (i.e. a one-way bearing). Twenty-two unimpaired novice adults navigated a figure-eight track during six training sessions over two weeks. Participant mean speed improved roughly 60% for both chairs, with similar exponential improvement time constants (3 days) and final speeds. However, speed improvement mostly took place overnight rather than within the session for hand-clutching, and the physiological cost index was also about 40% higher. These results indicate that while hand-clutching is no more difficult to learn than a lever-drive, it is reliant on overnight improvement. Also, its increased maneuverability comes with decreased efficiency. We discuss how the yoked clutch may be particularly well suited for individuals with stroke during inpatient rehabilitation.

A renewable energy harvesting system using a mechanical vibration rectifier (MVR) for railroads

As the demand for clean and sustainable energy increases, it is useful to explore alternative energy strategies, including harvesting the kinetic energy of vibration. In this paper, we design and characterize a renewable energy-harvesting system that collects energy from rail track vibrations by using a mechanical vibration rectifier (MVR). The MVR consists of meshing gears and one-way bearings, and it transforms bidirectional vibrations into unidirectional rotation to improve the efficiency of transmission. A DC motor is used as a generator, and a supercapacitor is used to store the electricity. The operation of the MVR was modelled and simulated including vehicle-track contact, track vibration, the dynamic response of the MVR and an electromechanical analysis of the generator. A prototype was manufactured to demonstrate the feasibility of the design. A peak voltage of 58V comes close to meeting the requirements for practical usage in rail applications. These devices would be able to supply power for safety equipment and allow for emergency repairs in areas without power.

Design, fabrication, simulation and testing of an ocean wave energy converter with mechanical motion rectifier

Many wave energy converters have been developed in the past century with various power takeoff systems, including those devices with air turbines, linear electromagnetic motors, and hydroelectric components. Although these systems have their own advantages, power takeoffs are still recognized as the most important challenge in ocean wave energy technology. In this paper, a mechanical motion rectifier (MMR) based power takeoff system is proposed and prototyped for wave energy converter. This power takeoff system can convert the bidirectional wave motion into unidirectional rotation of generator by integrating two one-way bearings into a rack pinion system. A wave energy converter which contains a 1.2m buoy and MMR based power takeoff system was designed and fabricated in this paper. The models of power takeoff system and single-body wave energy converter were built and analyzed. The simulation results in regular wave show that MMR based power takeoff can produce more power comparing with linear damping power takeoff system and the optimal PTO damping of MMR system is smaller than that of linear damping system. Lab testing of power takeoff mechanism and ocean testing of the overall ocean wave converter system were also conducted to validate the concept of MMR design. The disengagement and engagement of one-way bearings in the mechanical motion rectifier system were verified in both lab and ocean test.

A portable high-efficiency electromagnetic energy harvesting system using supercapacitors for renewable energy applications in railroads

As the demand for alternative sources of energy has increased, harvesting abundant environmental energy such as vibration energy including track vibrations in railway systems has attracted greater attention. In this study, we develop a portable high-efficiency electromagnetic energy harvesting system with supercapacitors that converts the energy of track vibrations into electricity. The generated electricity is stored in the supercapacitors and used in remote areas for safety facilities or in standby power supplies for rail-side equipment. The proposed system consists of a mechanical transmission and a regulating circuit. Acting as the energy input and transmission, Gears and a rack amplify the small vibrations of the track, and one-way bearings enhance efficiency by transforming bidirectional motion to unidirectional rotation. Supercapacitors are used in the vibration energy harvesting system for the first time. The supercapacitors permit the storage of energy from rapidly changing transient currents and a steady power supply for external loads. The proposed system is demonstrated through dynamic simulations, which show the rapid response of the system. An efficiency of 55.5% is demonstrated in bench tests, verifying that the proposed electromagnetic energy harvesting system is effective and practical in renewable energy applications for railroads.

Functional Redesign of Mantis 2.0, a Hybrid Leg-Wheel Robot for Surveillance and Inspection

The paper discusses the redesign of the second version of the Mantis hybrid leg-wheel mobile robot, conceived for surveillance and inspection tasks in unstructured indoor and outdoor environments. This small-scale ground mobile robot is characterized by a main body equipped with two front actuated wheels, a passive rear axle and two rotating legs. Motion on flat and even ground is purely wheeled in order to obtain high speed, high energetic efficiency and stable camera vision; only in case of obstacles or ground irregularities the front legs realize a mixed leg-wheel locomotion to increase the robot climbing ability; in particular, the outer profile of the legs, inspired by the praying mantis, is specially designed to climb square steps. The multibody simulations and the experimental tests on the first prototype have shown the effectiveness of the mixed leg-wheel locomotion not only for step climbing, but also on uneven and yielding terrains. Nevertheless, extensive experimental tests have shown that the front wheels may slip in the last phase of step climbing in case of contact with some materials. In order to overcome this problem, the leg design has been modified with the introduction of auxiliary passive wheels, which reduce friction between legs and step upper surface; these wheels are connected to the legs by one-way bearings, in order to rotate only when they are pulled by the front wheels, and remaining locked when they have to push forward the robot. The influence of the auxiliary wheels on the front wheels slippage is investigated by means of theoretical analysis and multibody simulations.

Design, Modeling, and Simulation of a Geared Infinitely Variable Transmission

An infinitely variable transmission (IVT) to provide a continuous output-to-input speed ratio from zero to a certain value is designed, and its working principle is illustrated. It is a geared IVT (GIVT), since its function to achieve the continuously varied speed ratio is implemented by gears. Crank-slider systems are used in the GIVT; the output-to-input speed ratio is changed with the crank length. Racks and pinions, whose motion is controlled by planetary gear sets, are used to change the crank length when the cranks rotate. One-way bearings are used to rectify output speeds from different crank-slider systems to obtain the output speed of the GIVT. Since the crank-slider systems can introduce variations of the instantaneous speed ratio, a pair of noncircular gears is designed to minimize the variations. A direction control system is also designed for the GIVT using planetary gear sets. Finally, a vehicle start-up simulation and a wind turbine simulation to maintain a constant generator speed are developed based on a GIVT module in the Matlab Simulink environment.

Modeling and Control of an Infinitely Variable Speed Converter

Traditional transmission in a vehicle has low efficiency and that in a wind turbine has a constant output-to-input speed ratio, which needs a power converter to regulate the current frequency that can be fed into the grid. Different types of continuously variable transmission (CVT) have been developed for vehicle and wind turbine applications, which allow optimal engine speeds to be selected for different driving conditions in the former and can generate constant-frequency current without using a power converter in the latter. An infinitely variable speed converter (IVSC) is a specific type of CVT that can achieve a zero speed ratio and transmit a large torque at a low speed ratio. An IVSC with drivers that convert an eccentric motion of cams to a concentric motion of the output shaft through one-way bearings is introduced, and an active control system with a combined feedback and feed-forward control that can automatically adjust the eccentricity of outer cams to control the speed ratio of the transmission is developed. The kinematic model of the IVSC is derived and fitted by a polynomial function to serve as the feed-forward function in the control law. The feedback control is used to reduce the system error. A dynamic model of the IVSC is derived to investigate the effect of the dynamic load on the input and output speeds. Static and dynamic tests were conducted to validate the kinematic model of the IVSC. The variation of the average output speed per revolution of the output shaft is 0.56% with respect to the desired output speed in the simulation and 0.91% in the experiments.

A New Structure of the Washing Machine Clutch Research and Development

In order to reduce the cost of washing machine clutch, clutch manufacturing process to improve through conventional washing machine JLX-N-5.0 clutch structure analysis, a new structure of the washing machine clutch, in ensuring the technical performance of the major premise, the clutch brake structure was improved to cancel one-way bearing, narrow diameter brake wheel, change the brake means and planetary gear train positioned. Comparative experimental results show that the clutch brake performance and a substantial increase in operating performance, with simple technology and low cost characteristics.

A New Structure of the Washing Machine Clutch Research and Development

In order to reduce the cost of washing machine clutch, clutch manufacturing process to improve through conventional washing machine JLX-N-5.0 clutch structure analysis, a new structure of the washing machine clutch, in ensuring the technical performance of the major premise, the clutch brake structure was improved to cancel one-way bearing, narrow diameter brake wheel, change the brake means and planetary gear train positioned. Comparative experimental results show that the clutch brake performance and a substantial increase in operating performance, with simple technology and low cost characteristics.

압전회전작동기를 이용한 스텝모터에 관한 연구

In this paper, a new type of pi+ezoelectric stepping motor is designed, manufactured and tested. This motor is composed of piezoelectric torsional actuator and a pair of one-way clutch bearings. The torsional actuator consists of 16-polygonal tube of piezoceramic that can produce an angular displacement associated with shear mode. One-way clutch bearing converts oscillation of torsional actuator into a continuous stepping rotation. The proposed stepping motor does not require any conversion mechanism for stepping motion like any other motors. In the design process, the shear resonance mode of piezoelectric actuator is analyzed by using a commercial finite element analysis program, and the performance of the fabricated torsional actuator is measured. <TEX>$0.124^{\circ}$</TEX> of maximum angular displacement is measured in square wave excitation on the actuator only. The stepping motor is manufactured by assembling a pair of one-way clutch bearings and the torsional actuator. The maximum rotation speed of 72rpm and the blocking torque of 3.136 mNm are measured at 3540 Hz and 100V/mm. Once the proposed piezoelectric stepping motor is miniaturized, it can be used for many compact and precise moving applications.

Piece-Wise Linear Dynamic Systems With One-Way Clutches

One-way clutches and clutch bearings are being used in a wide variety of dynamic systems. Motivated by their recent use as ratchets in piezoelectric actuators and decoupling devices in serpentine belt drives, a method of analysis of systems containing one-way clutches is presented. Two simple systems are analyzed. The goal of the first is the power transmission which would be of concern in an actuator. The goal of the second is decoupling large inertia elements to reduce loads in an oscillating system, the objective of the clutch in a serpentine belt drive. Results show how system parameters can be tuned to meet the desired performance of these piece-wise linear systems.

Sea Beaver: Design, Construction, and Performance of a Human-Powered Submersible

This paper reports on the history of the Massachusetts Institute of Technology's entry in the 2nd International Human-Powered Submarine Race. The design of this entry was an evolution of the MIT design (named Icarus) from the first competition, held in 1989. Anticipating an increase in competitive entries, the new MIT entry (hereafter referred to as Sea Beaver) was designed to be more reliable and faster than Icarus. Sea Beaver was designed with a maximum diameter four inches smaller than Icarus. This change in cross section forced a change from a rotary to linear pedaling mechanism. The linear pedal motion was transferred to the drive shaft through an innovative arrangement of pulleys and one-way hub bearings. This arrangement allowed the pedals to remain independent from one another, opening up the possibility to experiment with different pedaling cadences. The propeller was designed for efficiency and to minimize the possibility of entanglement with lines along the course. The steering system was arranged to take up the least volume inside the hull as possible. In addition to taking advantage of experience gained in the design of Icarus, the MIT team also made significant advances in construction techniques. The hull, propellers, and nose cones were all fabricated from molds built by team members. Compared with the Icarus construction history, Sea Beaver was completed in less time, at less cost, with more spare parts available during the competition. For the design and construction of the propulsion system, the Sea Beaver team received the 1991 Medal of Engineering Excellence from Popular Science Magazine.

A Bench Mark Navigation System for Surface and Subsurface Vessels

A bench mark navigation system Composed of a single bottom-mounted beacon and a receiver using a single hydrophone is described. The system will provide range and relative bearing of the vessel with respect to the bottom-mounted unit. The bottom-mounted unit is standard; however, the shipboard unit utilizes a multimode transducer. Range is determined by one-way timing and bearing is determined by using the unique properties of the multi-mode transducer. This device, a proprietary item of Raytheon Company, is a cylindrical, ceramic, piezoelectric element. Electrodes are placed at 90-degree intervals on the cylinder, and the four signals made available can be combined to generate two quadrature dipole patterns and an omni pattern. These signals are sufficient to determine relative bearing. A prototype system has been designed. Besides the necessary preamplifiers, filters and summing circuits, a digital, an analog, and a hybrid display are being developed. Sources of error in the general system and system accuracies are described.