Wheel Mode Research Articles

Design of multimodal transformable wheels for amphibious robotic vehicles

Amphibious vehicles are versatile for locomotion on both water and land; to reduce the complexities of structure and control, an amphibious vehicle is expected to use a single propulsion system without additional screw propellers or water jets; as vehicles are typically driven by wheels that are efficient for smooth land locomotion, how to make the wheels also as water propellors for multimodal transformations is meaningful, while such wheels are less explored. From this motivation, in this short article, we report the design of a multimodal transformable wheel with three driving modes (wheel mode, forward-propellor mode, and backward-propellor mode) and the integrated mode-locks for each driving mode. To achieve the multimodal transformations of the wheel, we design the integrated mode-transform mechanism and mode-lock mechanism, the two mechanical implementations are driven by only two actuators and are compact with low inertia and low control complexity, with the kinematic properties provided during the wheel transformations.

Adaptive Control for Suspension System of In-Wheel Motor Vehicle with Magnetorheological Damper

This study proposes two adaptive controllers and applies them to the vibration control of an in-wheel motor vehicle’s (electric vehicle) suspension system, in which a semi-active magnetorheological (MR) damper is installed as an actuator. As a suspension model, a nonlinear quarter car is used, providing greater practical feasibility than linear models. In the synthesis of the controller design, the values of the sprung mass, damping coefficient and suspension stiffness are treated as bounded uncertainties. To take into account the uncertainties, both direct and indirect adaptive sliding mode controllers are designed, in which the principal control parameters for the adaptation law are updated using the auto-tune method. To reflect the practical implementation of the proposed controller, only two accelerometers are used, and the rest of the state values are estimated using a Kalman observer. The designed controller is applied to a quarter car suspension model of an in-wheel motor vehicle featuring an MR damper, followed by a performance evaluation considering factors such as ride comfort and road holding. It is demonstrated in this comparative work that the proposed adaptive controllers show superior control performance to the conventional proportional–integral–derivative (PID) controller by reducing the vibration magnitude by 50% and 70% for the first and second modes, respectively. In addition, it is identified that the second mode (wheel mode) of the in-wheel motor vehicle is more sensitive than the first body mode depending on the mass ratio between the sprung and unsprung mass.

W-Leg Jumping Robot: Mechanical Design, Dynamical Analysis and Simulation of Jumping Dual Wheel-Leg Hybrid Robot

This study primarily focuses on design, mathematically model and simulate a novel two wheel-legged hybrid robot called W-Leg Jumping robot, which has a unique ability to overcome step-like obstacles efficiently. In general, in transformable wheel-leg robot studies, the leg and wheel structure perform their movements in an interdependent manner. However, in this study, it is aimed to design a robot in which the leg and wheel structure can move independently of each other and to develop a robot that can easily overcome obstacles on flat surfaces with the wheel mode and with the leg mode. The robot can fold its legs hidden within the wheels and deploy its two degree of freedom (DoF) legs when it detects step-like obstacles. This mechanism allows the robot to overcome an obstacle with a height of twice the radius of the robot's open/close mechanism of the legs, along with the two-dimensional kinematic and dynamic analyzes of the legs, are presented in detail within the scope of this study proportional-integral-derivative (PID) controller is designed to control the joint angles of the legs. The reference angle values to be followed according to the height of the obstacle are determined using artificial neural network (ANN). Additionally, motion simulations of the robot are conducted for four different obstacle heights (20, 30, 40, and 50 cm). As a result of the PID controller, when exceeding the highest obstacle of 50 cm, the average absolute joint angular tracking error is max. 1.8829°, average tracking error max. 0.265 s and max.

On the efficient simulation of pass-by noise signals from railway wheels

The article presents an approach for calculating pass-by sound pressure radiated from railway wheels in the time domain using moving Green’s functions. The Green’s functions are obtained by using Finite Element (FE) and Boundary Element (BE) methods in the frequency domain, subsequent inverse Fourier transform, followed by convolution with a time series of rolling contact forces to obtain the pass-by time signals. However, traditional BE methods are computationally expensive due to the low structural damping of the wheel, necessitating a high frequency resolution.To overcome this issue, a modal approach is introduced in which the pass-by sound radiated by each wheel mode is calculated separately. This approach incorporates the dynamic response of the wheel in the time-domain processing and thus reduces the cost of the BE solution. A modal source signal is introduced to describe the excitation of each mode at each time step. The sound field radiated by unit modal amplitudes is calculated in BE and subsequently approximated by spherical harmonic (SH) equivalent sources, which allows for efficiently calculating acoustic transfer functions for varying relative positions of the wheel and a stationary receiver. Convolution of the source signal with the moving acoustic transfer function produces the pass-by pressure signal.The article investigates the directivity of the radiation from each mode and finds that most modes, including those with dominant radial deflection, radiate in mostly axial direction at high frequencies. Modes that dominate the pass-by pressure level are identified, both in frequency bands and with respect to the relative positioning of the wheel to the receiver. Finally, it is found that an SH expansion order of approximately 30 is required to satisfy the employed error measures, although lower orders may suffice for an auralisation of the signal.

Design and Analysis of Transformable Wheel-legged Mobile Robot

Wheeled mobile robot has good ground motion ability, fast moving speed and low energy consumption, but poor obstacle surmounting performance. In order to make the mobile robot have the motion performance in complex environments, the wheel mechanism and the wheel-leg mechanism are coupled and designed, and a deformable wheel-leg structure is designed. The mobile robot can not only move in the wheel mode, but also switch to the wheel-leg mode to adapt to the complex motion environment. The deformable wheel-leg mechanism is composed of a four-bar linkage, and the static analysis of key components is carried out in ANSYS.

REG\u03b3 regulates circadian clock by modulating BMAL1 protein stability

Endogenous clocks generate rhythms in gene expression, which facilitates the organisms to cope through periodic environmental variations in accordance with 24-h light/dark time. A core question that needs to be elucidated is how such rhythms proliferate throughout the cells and regulate the dynamic physiology. In this study, we demonstrate the role of REGγ as a new regulator of circadian clock in mice, primary MEF, and SY5Y cells. Assessment of circadian conduct reveals a difference in circadian period, wheel mode, and the ability to acclimate the external light stimulus between WT and KO littermates. Compared to WT mice, REGγ KO mice attain the phase delay behavior upon light shock at early night. During the variation of 12/12 h light/dark (LD) exposure, levels of Per1, Per2, Cry1, Clock, Bmal1, and Rorα circadian genes in suprachiasmatic nucleus are significantly higher in REGγ KO than in WT mice, concomitant with remarkable changes in BMAL1 and PER2 proteins. In cultured cells depleted of REGγ, serum shock induces early response of the circadian genes Per1 and Per2 with the cyclic rhythm maintained. Mechanistic study indicates that REGγ directly degrades BMAL1 by the non-canonical proteasome pathway independent of ATP and ubiquitin. Silencing BMAL1 abrogates the changes in circadian genes in REGγ-deficient cells. However, inhibition of GSK-3β, a known promoter for degradation of BMAL1, exacerbates the action of REGγ depletion. In conclusion, our findings define REGγ as a new factor, which functions as a rheostat of circadian rhythms to mitigate the levels of Per1 and Per2 via proteasome-dependent degradation of BMAL1.

Early warning and real-time control of construction safety risk of underground engineering based on building information modeling and internet of things

The objective of this study is to establish a safety risk warning system for the construction of underground engineering and to solve the problems existing in current construction of underground engineering, such as large investment, long construction period, complex construction environment, and many unforeseen risk factors. In this research, building information modeling (BIM) technology and Internet of things technology are used to analyze the construction of safety risk warning system for underground engineering. Firstly, the concept and application of BIM technology and safety risk warning of underground engineering construction are introduced. Then, aiming at the existing safety problems of underground construction, the construction principle of underground construction safety indicator system, the establishment steps of indicator system and safety risk indicator system are introduced in detail, and a set of early warning and control system of safety risk of underground construction based on BIM technology and Internet of things technology is established. At last, the working mode and real-time monitoring of underground engineering early warning based on BIM technology and Internet of things are expounded. The results show that the underground engineering prediction system based on BIM technology and the Internet of things adopts the working mode that combines the circular safety risk warning wheel mode and the three-dimensional safety risk warning mode. Moreover, the real-time dynamic monitoring of the security risk warning system can be achieved through the periodic recording and testing of process indicators by the BIM management platform. It is hoped that this study can provide a good management platform for underground construction safety and reduce the occurrence of safety accidents in underground construction.

Investigation of Hybrid Locomotive Robot for Anti-Personnel Mine Detection

Most of landmine detection robots proposed so far have been strongly restricted from locomotion inside the mine field because they cannot cross over the mine. So we have proposed a mine detection robot with hybrid locomotion, which can enter inside the minefield with low ground surface contact, which can cross over the mine instead of changing its path and scan landmines directly using Electro Magnetic Induction sensor. The hybrid locomotion proposed in the robot uses the frame walking technique and the conventional wheeled locomotion. The robot switches over the locomotion mechanism from wheeled to leg when mine is detected and vice versa with a lead screw mechanism. The leg locomotion is achieved by frame walking technique where the two frames translate with the help of lead screw mechanism. A purpose of adopting this combination is to evade anti-personnel landmines which are relatively smaller in comparison to their anti-tank landmine counterparts. The robot initially starts in wheeled mode and upon detection of metal, pulls in the frame walking algorithm. The robot also deploys an obstacle avoidance algorithm when working in wheel mode.

Implementation of a Reconfigurable Robot to Achieve Multimodal Locomotion Based on Three Rules of Configuration

SUMMARYIn this paper, we focus on the configuration design of a reconfigurable robot that merges the functions of wheels, tracks, and legs together. A deformable rim is utilized to make the robot wheel reconfigurable to change its locomotion mode. Three rules of configuration design to achieve reconfiguration between different modes are proposed: (1) in wheel mode, the track wheel set should be hidden inside the wheel rim; (2) in track/leg mode, the folded wheel rim should be hidden inside the caterpillar loop; (3) the circumference of the wheel rim in wheel mode should be equal to the length of the track ring in track mode. According to these rules, the configuration of the deformable rim, track wheel set, and telescopic spoke are analyzed and designed. A prototype of the reconfigurable wheel is fabricated by three-dimensional printing, and its functions of locomotion in different modes, the switch between different modes, and its load-bearing ability are tested, verifying the effectiveness of the configuration design. Furthermore, a prototype of the reconfigurable robot is manufactured by computerized numerical control (CNC) machining to verify the structural design of the reconfigurable wheel. Compared to traditional hybrid robots with separate wheels, tracks, and legs, this reconfigurable design lends the multimodal robot both excellent terrain adaptability and a compact structure; thus, it can be widely used as a universal mobile platform in search and rescue missions and explosive object disposal missions.

The critical effect of rail vertical phase response in railway curve squeal generation

Squeal of rail-bound vehicles emitted in tight curves is characterized by high sound pressure levels at pure medium and high frequencies. Many models have been proposed in the literature to explain the occurrence of this noise with different instability mechanisms: negative damping due to falling friction or instability with a constant friction coefficient. The aim of the paper is to contribute to the understanding of the instability mechanisms in the case of a constant friction coefficient. A stability analysis of the wheel/rail contact dynamics in curve is performed by using an equivalent point contact model combined with wheel and rail modal bases. Results show that even with an assumption of a constant Coulomb friction coefficient, two types of instabilities may occur in the wheel/rail system: classical mode coupling and instabilities due to negative damping added to a single wheel mode when the track dynamical behavior, especially in the vertical direction, is included. For this second type of instabilities, an 1-degree of freedom model can be formulated. By using this model, it is found that the equivalent damper behavior of the infinite track is the origin of these instabilities.

Effect of rail dynamics on curve squeal under constant friction conditions

Curve squeal noise is a severe railway noise problem that can occur when a railway vehicle negotiates a sharp curve. It is usually characterised by a very loud tonal noise and can be very annoying for people in the vicinity. It is generally attributed to friction-induced instability, either due to a falling friction characteristic with increasing sliding velocity or to a mode coupling mechanism which can lead to instability even for a constant friction coefficient. The squeal frequency is usually associated with one or more wheel modes. However, the wheel is coupled dynamically to the track and insufficient attention has been paid in previous research to the role played by the rail dynamic behaviour. In this paper, the effect of the rail dynamics on curve squeal under constant friction conditions is investigated by means of different modelling approaches. The rail is firstly modelled using a waveguide finite element (WFE) model and it is found that the inclusion of the rail dynamics in the model can lead to squeal in some situations where it would otherwise not occur. Various effects are then considered that may introduce additional resonant behaviour into the rail dynamics. These include the effect of the rail cross mobility, rail cross-section deformation, the influence of the periodic support of the rail and reflections between multiple wheels on the rail. The effect of the rail pad stiffness is also explored. However, the results show that all these factors have little influence on the predicted curve squeal instabilities. By means of a reduced model, the main characteristics of the rail dynamics that can result in squeal are then assessed. It is shown that the mass and damping-like behaviour of the infinite rail are at the origin of the instabilities rather than any modal behaviour of the track. Curve squeal may occur for a single wheel mode even if the rail is represented by a damper, which is a close approximation to the vertical mobility of the track at high frequencies. This forms a third possible mechanism for curve squeal in addition to falling friction and wheel mode coupling.

A reconfigurable hybrid wheel-track mobile robot based on Watt II six-bar linkage

This paper presents the design and development of a novel reconfigurable hybrid wheel-track mobile robot (RHMBot). This new reconfigurable mobile robot is constructed based on a Watt II six-bar linkage; through structure reconfiguration, it can provide three locomotion modes as wheel mode, tracked mode, and climbing and roll-over mode. Mechanical design of the proposed RHMBot is introduced, and using mechanism decomposition kinematics of the reconfigurable frame is investigated. Locomotion of the robot is then interpreted associated with transformation of the reconfigurable frame. Further, deformation of the deformable track belt is characterized and static analysis of the reconfigurable frame is accomplished. Numerical simulation of the proposed reconfigurable frame is subsequently implemented, integrated with driving-torque associated parametric study, leading to optimization of the structure parameters. Consequently, prototype of the proposed RHMBot is designed and developed; exploiting which a series of field tests are conducted verifying feasibility and manoeuvrability of the proposed multi-locomotion mobile robot.

Analysis of ground handling characteristic of aircraft with electric taxi system

Electric landing gear drive equipped with traction motors can provide taxi capability without the use of main engines or tractor. The ground handling characteristic of aircraft with electric taxi system is analyzed. The new mathematic model of aircraft ground maneuver is established, considering the 6-degree-freedom aircraft body and the flexible main strut and the powered wheel. Quasi-steady method is applied to calculate tire side forces and moments, to determine side slip. The simulation for the ground steering response of aircraft with electric taxi system is done by employing ADAMS and Simulink co-simulation platform. The dynamic responses of aircraft ground steering and landing gear spin-up and spring back are simulated. Different taxi conditions including powered nose wheel mode and powered main wheel mode are compared. Four conclusions are obtained: electric taxi system helps the aircraft turn on the spot and the turning radius is smaller than the aircraft using engines; differential powered main wheel mode has the minimum turning radius while turning-circle with uniform velocity, and it has smaller difference between two vertical loads of main landing gear than powered nose wheel mode; in the case of the same steering angle, the extreme velocity of differential powered main wheel mode before side slip is larger than powered nose wheel mode; and pre-rotation of powered main wheel decreases the spin-up drag load and spring back drag load.

Development of the Humanoid Disaster Response Platform DRC-HUBO+

This paper describes a humanoid robotics platform (DRC-HUBO+) developed for the Defense Advanced Research Projects Agency Robotics Challenge (DRC) Finals. This paper also describes the design criteria, hardware, software framework, and experimental testing of the DRC-HUBO+ platform. The purpose of DRC-HUBO+ is to perform tasks by teleoperation in hazardous environments that are unsafe for humans, such as disaster zones. We identified specific design concepts for DRC-HUBO+ to achieve this goal. For a robot to be capable of performing human tasks, a human-like shape and size, autonomy, mobility, manipulability, and power are required, among other features. Furthermore, modularized joints and a user-friendly software framework were emphasized as design concepts to facilitate research on the robot tasks. The DRC-HUBO+ platform is based on DRC-HUBO-1 and HUBO-2. The torque of each joint is increased compared to that in DRC-HUBO-1 owing to its high reduction ratio and air-cooling system. DRC-HUBO+ is designed with an exoskeletal structure to provide it with sufficient stiffness relative to its mass. All wires are enclosed within the robot body using a hollow shaft and covers to protect the wires from external shock. Regarding the vision system, active cognition of the environment can be realized using a light-detection and ranging sensor and vision cameras on the head. To achieve stable mobility, the robot can transition from the bipedal walking mode to the wheel mode using wheels located on both knees. DRC-HUBO+ has 32 degrees of freedom (DOFs), including seven DOFs for each arm and six DOFs for each leg, and a solid and light body with a height of 170 cm and a mass of 80 kg. A software framework referred to as PODO, with a Linux kernel and the Xenomai patch, is used in DRC-HUBO+.

Mode-Scheduling Steering Law of VSCMGs for Multi-Target Pointing and Agile Maneuver of a Spacecraft

This study proposes a method of selecting a set of gimbal angles in the final state and applies the method to the mode-scheduling steering law of variable-speed control moment gyros intended for multi-target pointing manoeuvres in the three-axis attitude control of a spacecraft. The proposed method selects reference final gimbal angles, considering the condition numbers of the Jacobian matrix of the reaction wheel mode in the final state of a single manoeuvre and that of the constant-speed control moment gyro mode at the start of the upcoming manoeuvre to keep away from the singularities. To improve the reachability of reference final gimbal angles, the nearest set of gimbal angles among nominated sets according to the Euclidean norm is selected as the reference final set at the middle of the single manoeuvre, and then realised by adopting gimbal angle feedback steering logic using null motion. In addition, the manoeuvre profile is designed such that the second half of the single manoeuvre is more gradual and takes longer than the first. Numerical simulation confirms the validity of the proposed method in consecutive manoeuvres.

Mechanism design and motion ability analysis for wheel/track mobile robot

A wheel/track mobile robot with a one-way tail rod is studied. First, from the analysis of its performance, the mechanical structure of the wheel/track mobile robot is designed and the hardware composition of its control system is given. Second, based on the analysis of its variable structure movement process, the variable structure model of wheel/track mobile robot is established using the geometry analysis method. Third, two kinds of analysis are proposed. One is analysis of the wheel movement on flat ground. Another is track obstacle-crossing kinematics of the robot, in which the conditions for its stairs-climbing are determined. Then, the dynamical model of stairs-climbing is established either in wheel mode or in track mode using the classical mechanics analysis on the robot during the stairs-climbing process. Through simulation and experiments, the effectiveness of the model and the evaluation method of the wheel/track mobile robot in stairs-climbing are verified, which can provide design and analysis foundations for the wheel/track mobile robot.

Steering law for a cluster of magnetically suspended momentum wheels with vernier gimballing capability

This paper focuses on the steering law for a magnetically suspended momentum wheel (MSMW) cluster with vernier gimballing capability. Firstly, the dynamical model of the spacecraft equipped with the MSMW cluster is constructed in a generalized form. Then a new steering law for the MSMW cluster is proposed to switch between two operation modes: the conventional momentum wheel mode for outputting spin torque, and the double gimbaled wheel mode for outputting the gyroscopic torques. Compared with the traditional steering law, the proposed steering law with two modes switch can avoid the small vernier gimbal angles saturation. Finally, simulation results demonstrate the merits of using vernier gimballing capability and the effectiveness of the proposed steering law in providing the command torques and avoiding the saturation of the vernier gimbal angles.

Simulation of Motion Control for a Modular Robot of Five Degrees of Freedom

This project shows the simulation of a robotic modular system. It has one kind of module, which can couple with two more. The modules have five degrees of freedom (DOF), and can move in four different ways: independent module mode, caterpillar mode, snake mode and wheel mode. The last three kinds of movements need to have several modules coupled. Each module can move either using two pivots at its ends or by using tiny wheels that allow it to move in a direction that is perpendicular to the direction it follows when using its pivots; these gyratory elements also allow the module to rotate around one of its ends. The system controls based on sine functions.

Rail corrugation growth accounting for the flexibility and rotation of the wheel set and the non-Hertzian and non-steady-state effects at contact patch

In this work, a simulation tool is developed to analyse the growth of rail corrugation consisting of several models connected in a feedback loop in order to account for both the short-term dynamic vehicle–track interaction and the long-term damage. The time-domain vehicle–track interaction model comprises a flexible rotating wheel set model, a cyclic track model based on a substructuring technique and a non-Hertzian and non-steady-state three-dimensional wheel–rail contact model, based on the variational theory by Kalker. Wear calculation is performed with Archard's wear model by using the contact parameters obtained with the non-Hertzian and non-steady-state three-dimensional contact model. The aim of this paper is to analyse the influence of the excitation of two coinciding resonances of the flexible rotating wheel set on the rail corrugation growth in the frequency range from 20 to 1500 Hz, when contact conditions similar to those that can arise while a wheel set is negotiating a gentle curve are simulated. Numerical results show that rail corrugation grows only on the low rail for two cases in which two different modes of the rotating wheel set coincide in frequency. In the first case, identified by using the Campbell diagram, the excitation of both the backward wheel mode and the forward third bending mode of the wheel set model (B-F modes) promotes the growth of rail corrugation with a wavelength of 110 mm for a vehicle velocity of 142 km/h. In the second case, the excitation of both the backward wheel mode and the backward third bending mode (B-B modes) gives rise to rail corrugation growth at a wavelength of 156 mm when the vehicle velocity is 198 km/h.

Development of a 3-D quasi-steady-state tyre model for on-road and off-road vehicle dynamics simulations: Part II - off-road rigid wheel model

This study presents the development of a simplified brush-based tyre model for on-road simulation, together with a simplified off-road wheel/tyre model that has the capability to revert back to on-road trend of behaviour on firmer soils. The on-road tyre model is developed based on empirical data collected by NHSTA, while the off-road tyre model is developed based on observations of experimental data and photographic evidence collected by various terramechanics researchers within the last few decades. Using theoretical analysis and empirical data, the tyre deformation geometry is determined to establish the tractive forces in off-road operation. The first step of any off-road vehicle is to model the condition where the soil is much more deformable than the tyre, where the tyre can be modelled as a rigid wheel. This study explores the development of the rigid wheel mode of the model, using dry sandy terrain, an example of extremely deformable soil. This paper is the second of three papers on the modelling of tyres for both on and off-road operations.