Passive Rollers Research Articles

ВЛИЯНИЯ ВОЗДЕЙСТВИЙ ПРИКАТЫВАЮЩИХ КАТКОВ НА ОБОБЩЕННЫЕ СИЛЫ МАЛОГАБАРИТНОЙ ПОЧВООБРАБАТЫВАЮЩЕЙ МАШИНЫ

Increasing the efficiency of agricultural production, in particular the production of crop products in personal subsidiary plots, depends on the development and implementation of high-tech machines and their working units. The need for small-sized tillage equipment is increasing from year to year. But in order to increase the functionality of the equipment and the quality of soil preparation for sowing, it is necessary to study the possibility of using various additional working units.
 The purpose of the work is theoretical studies of the movement and kinematic connection of a trailed slatted-spiral roller with a walk-behind tractor, which make it possible to substantiate rational design and technological parameters of a small-sized tillage tool. The study used the provisions of classical mechanics and analytical geometry, methods of equilibrium and motion of mechanical systems based on differential and integral principles of mechanics. The design of active and passive rollers for a walk-behind tractor is considered, which allows to qualitatively prepare the soil for sowing at the depth of seeding, the influence of potential and non-potential effects on their generalized forces is revealed, the angular velocity and their acceleration are determined, as well as the dynamic characteristics of the moment of inertia of the rollers relative to the axes of rotation X4 and Z4 and their frames relative to the axes of rotation X3 and Z3. The difference in the generalized force for a passive roller relative to the angle φ 5.49 N∙m was obtained. The angular speed of the active roller is 23.0 rad/s higher than that of the passive roller, and as a result of research it was revealed that the moments of inertia of the active roller and its frame relative to the axles are significantly higher than that of the passive roller. Generalized forces for an active roller relative to the angle q = 2.58 N∙m and relative to the angle φ = 1.98 N∙m, for a passive roller - relative to the angle q = 2.32 N∙m and relative to the angle φ = 7.47 N∙m. The generalized forces for the potential effects of an active roller are Qθa=1.58 N∙m, Qφa=2.26 N∙m, for a passive roller Qθn=1.32 N∙m, Qφn= 4.60 N∙m. Mθa = 1 N∙m, Mφa = 114.63 N∙m; passive roller - respectively Mθn = 1 N∙m, Mφn = 178.9 N∙m

Design and Performance Evaluation of a Novel Vascular Robotic System for Complex Percutaneous Coronary Interventions.

The robotic-assisted percutaneous coronary intervention is an emerging technology with great potential to solve the shortcomings of existing treatments. However, the current robotic systems can not manipulate two guidewires or ballons/stents simultaneously for coronary bifurcation lesions. This paper presents VasCure, a novel bio-inspired vascular robotic system, to deliver two guidewires and stents into the main branch and side branch of bifurcation lesions in sequence. The system is designed in master-slave architecture to reduce occupational hazards of radiation exposure and orthopedic injury to interventional surgeons. The slave delivery device has one active roller and two passive rollers to manipulate two interventional devices. The performance of the VasCure was verified by in vitro and in vivo animal experiments. In vitro results showed the robotic system has good accuracy to deliver guidewires and the maximum error is 0.38mm. In an animal experiment, the interventional surgeon delivered two guidewires and balloons to the left circumflex branch and the left anterior descending branch of the pig, which confirmed the feasibility of the vascular robotic system.

Analysis of factors related to vertical vibration of continuous alternate wheels for omnidirectional mobile robots

Omnidirectional mobile robots (OMRs) are capable of arbitrary motions in arbitrary directions without changing the direction of wheels since they perform 3-DOF (degree of freedoms) motions on a plane. Various omnidirectional wheels including the continuous alternate wheel (CAW) with passive rollers for OMRs have been researched. The CAW has been developed for the purpose of minimizing vibration. The CAW has alternating inner and outer rollers around the wheel which makes nearly continuous contact with the ground. The ideal CAW reduce vibration for certain; however, the real CAW fail to do so due to various errors. In this regard, more research is needed to bring vibration under acceptable tolerance. In this paper, vertical vibration characteristics of the real CAW with tolerance are researched. Simulation models of CAWs are implemented using flexible body dynamics of Recurdyn. To verify vibration characteristics of the model, simulation results are compared with experimental results from the improved CAW with five rollers set (CAW5). Vertical vibration is affected by various factors: geometry errors, the gap, the thickness of flexible body, the angular velocity, the alignment angle, the load and the elasticity of flexible body, etc. To efficiently analyze the effects of various factors, dynamic simulations are conducted using Taguchi method. As a result, it is found that the main factors which affect vibration are the angular velocity and the alignment angle followed by the geometry errors, the load, the elasticity of flexible body, the thickness of flexible body and the gap. This process can be applied to the analysis of the other omnidirectional wheels with passive rollers.

2P1-T09 平面正八角形構造をした劣駆動歩行ロボットの開発と基礎実験

This paper proposes a novel underactuated locomotion robot that has high stiffness and reproduces the gait property equivalent to an eight-legged rimless wheel walking on a slippery road surface. First, we describe the overview of the experimental machine we developed and its mechanical features. Second, we develop the equations of motion and collision for the ideal model with small passive rollers, and discuss the collision dynamics for stance-leg exchange with the prospect of transition to non-instantaneous double-support motion. Third, we perform numerical simulations to understand the fundamental properties of the gait rolling on a rigid road surface, and discuss its similarity to limit cycle walking on a slippery road surface.

2P1-T06 リミットサイクル型動歩行のデータ計測システムの開発と基礎実験

The authors are developing a novel data measuring system for pseudo walking gait of a rimless wheel (RW) aiming at experimental verification of the stability principle underlying limit cycle walking with constraint on impact posture. This system consists of an 8-legged RW with small passive rollers, a DC motor fixed on the flame for driving the RW, and an up-and-down movable surface above the RW that reproduces the floor dynamics. Different from the traditional actuated RW model, a DC motor fixed on the frame can reduce the error of the vibration during impacts and help us to measure the angular velocity exactly. Vertical mode and horizontal mode are designed to investigate various of the gait properties. As a result, metastable walking gaits are generated in both modes.

Worm wheel mechanism with passive rollers

In this study, we developed new worm wheel mechanisms with passive rollers as their teeth and confirmed useful functions of these worm wheels with passive rollers to transmit power from worm gears with higher energy efficiency than ordinary worm wheels. By using passive rollers as their teeth, the developed worm wheels could realize high-power transmission efficiency with rolling frictional resistance instead of sliding frictional resistance. A worm wheel with conical passive rollers and one with disk-shaped passive rollers was fabricated as prototypes and examined in experiments. Smooth back-drivability of the worm wheels with passive rollers, which is difficult to realize with conventional worm wheels, was also demonstrated in the experiments. These serial experiments revealed that the developed worm wheel mechanism with passive rollers can replace conventional worm wheels with the same number of teeth and module in ordinary power transmission mechanisms with worm gearing and realize higher energy efficiency and smooth back-drivability. These features can be very useful to realize safe and soft actuators for automation systems in a human environment.

307 受動ローラ式歯車を用いたウォームギア機構の研究(機械要素・設計工学II)

307 受動ローラ式歯車を用いたウォームギア機構の研究(機械要素・設計工学II)

Research on the Vibration of Sheet Metal near the Zinc Pot Area in Continuous Hot-Dip Galvanizing Line

Large vibration of the sheet metal near the air knife is one of the main factors controlling the accuracy of thickness of the cladding zinc in continuous hot-dip galvanizing line. Lots of vibration tests are carried out on the strip and main equipments in the zinc pot area of a galvanizing line during downtime and operation in order to diagnose causes of the large vibration of the strip near the air knife. Theoretic foundation of adjustment of control parameters to suppress the strip vibration is established. Main mechanisms of large vibration of the strip are found by the theory of the transverse vibration of axially moving continua. The first one is the resonance of forced vibration induced by support movement aroused by passive rollers’ sloshing in the zinc pot, and the other is the parametrically excited resonance of the strip induced by tension fluctuation enlarged by local structural resonances of the cooling tower.

2A2-D08 二足歩行型ロボットの連続滑走(脚移動ロボット)

The purpose of this study is to increase the moving speed of the humanoid robot. In this study, we focus on roller-skates because of its simple mechanism, and we propose skating as a new moving method of the humanoid robot. It is faster and easier to control than walking. Passive rollers were installed on both feet of the small sized humanoid robot, and it was actually made skate as roller-skating. In addition, it had been examined continuous skating motion and it had been simulated the skating motion with MATLAB in order to improve moving ability of the humanoid robot.

Stability of steady motions of a mobile robot with roller-carrying wheels and a displaced centre of mass

The motion of a mobile three-wheel robotic vehicle on a horizontal surface is investigated. Passive rollers are fastened along the rim of each wheel, enabling each wheel not only to roll in the usual manner, but also to move perpendicular to its plane. Each of these wheels, as well as the ordinary wheels, is equipped with one drive, which rotates the wheel about its axis. The vehicle equipped with roller-carrying wheels can move in any direction with any orientation. The motion of the robot on a horizontal surface is studied in the case where the centre of mass of the robot deviates from the geometric centre of the triangular platform, and there is no slip at the points of contact of the rollers with the supporting surface. In the case of free motion of the robot, an additional first integral is pointed out and the exact solution found is analysed. An equation for specifying steady motions, under which a constant voltage is supplied to the DC motors that drive the wheels, is constructed. The stability of the rectilinear motion of the robot is investigated.

Modular Universal Unit for a Snake-Like Robot and Reconfigurable Robots

A modular universal unit (MUU) is developed for snake-like robots, which has 3 d.o.f. with a series of passive rollers around its cylindrical shell. Among those d.o.f., pitching and yawing are actuated by means of differential gears to accomplish a large ratio of propulsion to mass. The series of passive rollers around the cylindrical aluminum shell of the MUU form another large wheel that can be used as a driving wheel of mobile robots. The snake-like robot composed of those MUUs has more powerful propulsion and higher mobility. By connecting MUUs in different forms, we can also realize a connected mobile platform or a manipulator in addition to a snake-like robot. Owing to it having 3 d.o.f., two or more MUUs can be connected to make up many mobile robots or form a manipulator that exhibits high mobility and agility. Some typical reconfigurable robots composed of these MUUs are analyzed for locomotion control. Finally, the locomotion experiments and simulations are given to show the characteristics of this MUU.

Development of a Three Dimensional Snake-like Robot Perambulator II

Snake-like robots show higher capability of movement than conventional mobile robots. In order to achieve three-dimensional locomotion of snake-like robots, a 3D snake-like robot called Perambulator-Ⅱ is developed with the acquirement of powerful propulsion and high mobility. Perambulator-Ⅱ robot is composed of 3-DOF module, which implements pitching, yawing and rolling motion. The coupling drive is achieved through the differential mechanism composed of three bevels. A series of passive rollers are fixed on the unit cylinder body to add agility to the robot. The degrees of freedom of module are analyzed in detailing and the structure is designed on the basis of the mobility of robots. The control architecture of snake-like robot is presented. The decoupling of variables is completed. Serpentine and twist locomotion are applied on Perambulator-Ⅱ to test its performance. The experimental results show that Perambulator-Ⅱ has powerful mobility and agility.

Wheel Locomotion of a Biped Robot Using Passive Rollers – Large Biped Robot Roller Walking Using a Variable-Curvature Truck –

This paper proposes the leg-wheel locomotion of a biped robot. The feet of the robot consist of wheels that move forward with the periodic motion of a leg under a double-leg support. There are many types of approach leg-wheel hybrid systems; however, biped system with passive wheels is rarely used. A special axle mechanism is introduced so that the wheels could smoothly track a curved path for propulsive motion. Finally, the robot achieves not only straight and circular motion but also pivoting motion that is significantly faster than walking, while implementing a minimal number of simple components. The concept of locomotion, function of the mechanism, and experimental results are described in this paper.

Design and construction of continuous alternate wheels for an omnidirectional mobile robot

AbstractMany types of omnidirectional wheels with passive rollers have gaps between rollers. Since these gaps cause a wheel to make discontinuous contact with the ground, they lead to vertical and/or horizontal vibrations during wheel operation. In addition, the radii of passive rollers are related to the height of a bump an omnidirectional wheel can surmount. In this research a new design of the alternate wheel is proposed. Because this wheel makes continuous contact with the ground and has alternating large and small rollers around the wheel, it is termed a continuous alternate wheel (CAW). In this paper a design procedure is also presented to determine the optimum number of rollers, the radii of rollers and the inside inclination angle of an outer roller for given design specifications. The CAW based on this design is compared to the existing alternate wheels in terms of design. Finally, an actual continuous alternate wheel is constructed to verify validity of the design guidelines. © 2003 Wiley Periodicals, Inc.

Reduction in AC transport self-field losses for Ag-sheathed Bi2223 tapes by changing filament arrangements using two-axial rollers

Without introduction of resistive barriers, we succeeded in reducing AC transport self-field losses at 77 K for Ag-sheathed Bi2223 multifilamentary tapes with the m/spl times/n (m,n=3, 5) filament arrangements, fabricated by a rectangular deformation process using passive two-axial rollers. In spite of the main contribution of hysteresis loss of superconductor, the transport losses for the samples are reduced by approximately 50-70% compared with the values for Ag-sheathed Bi2223 tapes by a standard powder-in-tube process. Further change in filament arrangements using two-axial rollers leads to a further reduction in the loss values. From numerical calculations, the loss reduction is mainly ascribed to a division of field-free-core under AC current transmission.