Active Dual-wheel Caster Research Articles

ロッカーボギー機構を用いた全方向移動プラットフォームの開発

In connection with the super-aging society, there exists a growing interest in omnidirectional powered-wheelchairs that have superior mobility in a narrow space. An omnidirectional mobile robot composed of active dual-wheel caster assemblies can use general wheels such as rubber tires, so that it is easily applied to a powered wheelchair. This study is aimed at developing an omnidirectional mobile platform using active dualwheel caster assemblies in consideration of the run in a public road. An omnidirectional mobile platform using a rocker-bogie suspension system is proposed to improve the running ability, and several active dual-wheel caster modules are produced so as to be used in such a platform. In this paper, we give an overview of the active dual-wheel caster assemblies and the proposed robot, and describe the process of actual production of such modules and the associated experimental results.

Tip-over stability enhancement for omnidirectional mobile robot

Purpose – The purpose of this paper is to analyze the stability behavior of the omnidirectional mobile robot with active dual-wheel caster (ADWC) assemblies and provide a stable trajectory without any tip-over incident. The omnidirectional mobile robot to be developed is for transporting cuboid-shaped objects. Design/methodology/approach – The omnidirectional transport mobile robot is designed using an ADWC assemblies structure, the tip-over occurrence is estimated based on the support forces of an active footprint, the tip-over direction is predicted, the tip-over stability is enhanced to prevent the tip-over occurrence and a fast traveling motion is provided. Findings – The omnidirectional mobile robot tends to tip-over more on the sides with small ranges of tip-over angle. The proposed method for estimating the tip-over occurrence and enhancing the stability using the gyroscopic torque device was feasible as the tip-over prevention system of the omnidirectional mobile robot with ADWC assemblies. Originality/value – The research addresses the study of the tip-over stability for the omnidirectional mobile robot that possesses an active footprint. It also addresses the prediction of the tip-over occurrence using the derived dynamical model together with force-angle stability measure and the tip-over stability enhancement method using a single-gimbal control moment gyro device.

A study of tipping stability for omnidirectional mobile robot with active dual-wheel caster assemblies

A holonomic omnidirectional mobile robot with active dual-wheel caster assemblies is proposed as a robotic transport vehicle. With concern to the existence of sudden acceleration and other dynamical effects during maneuver, the tip-over instability monitoring is very important to prevent any unexpected injuries and property damage. This work presents the preventive method of the tip-over occurrence by estimating the tipping direction and stability metrics. The dynamical model of the omnidirectional mobile robot is derived to estimate the net force from the supporting reaction force at each wheel which is caused by the inertial and external forces. The direction of tipping and stability metric is estimated using moments stability measure. The performance of the tip-over prediction for an omnidirectional mobile robot with active dual-wheel assemblies is shown by the conducted simulations.

Tip-over Prediction for Omnidirectional Mobile Robot

This paper proposes a holonomic omnidirectional mobile robot with active dual-wheel caster assemblies as a robotic transport vehicle. With concern to the sudden dynamic changes during maneuver, the tip-over stability monitoring is very important. This work presents the estimation technique of the tip-over direction and the stability measurement. The dynamical model of the omnidirectional mobile robot is derived to estimate the net force from the supporting reaction force at each wheel which is caus ed bythe inertial and external forces. The direction of tipping and the stability metric is estimated using the force-angle stability measure (FASM). The performance of the tip-over prediction for an omnidirectional mobile robot with active dual-wheel assemblies is shown by the conducted simulations.

アクティブ双輪キャスタ機構を有するホロノミック全方向移動ロボットの動的制御

Recently, omnidirectional mobile robots with holonomic property have been studied actively. We have already developed a holonomic and omnidirectional mobile robot which consists of two active dual-wheel caster assemblies and also derived the kinematic models for the assembly and the mobile robot. In this paper, we further derive a dynamic model for the mobile robot by using the forces acting on the steering axis and construct a resolved acceleration control system based on the model to realize a dynamic control for the mobile robot. An experiment using a prototype robot is performed to prove the validity of the model and the effectiveness of the control system.

An Upper Drive-Active Dual-Wheel Caster Assembly and its Application for Constructing Holonomic and Omnidirectional Platform

A new mechanical upper-drive active dual-wheel caster assembly is developed and two types of holonomie and omnidirectional mobile robots which utilize this caster assembly are discussed in this paper. The new active caster assembly is equipped with two standard tires as its driving wheels. Two motors are mounted on the upper frame to drive each wheel independently through a series of gears and a belt. In this structure, the lower frame can steer arbitrary angles referred to the upper frame without any wiring problem, which inhibits practical application of the previous normal active dual-wheel caster assembly. The new active caster assembly is used to construct two types of holonomie and omnidirectional mobile robots. One is a conventional structure, and the other is a synchro-drive system. The kinematic models of the new active caster assembly and two types of mobile robots are derived and the characteristics of these two holonomic and omnidirectional mobile robots are illustrated by computer simulations using resolved velocity control.

An Omnidirectional Mobile Robot Using Multiple Active Dual-Wheel Caster Assemblies.

Recently, high mobilities of vehicles in industries are required for the automation of inspections and special works in narrow space. In this paper, we present a new type of holonomic and omnidirectional mobile robot platform using some driving assemblies, one of which consists of two independent driving wheel mechanisms just like active dual-wheel caster with an offset steered axis. The kinematic models of the wheel mechanism and mobile robot using two and three driving assemblies are derived and their models are used to construct a feedback control system based on a resolved velocity control for the robot. The effectiveness of the present method is illustrated by some computer simulations. Finally, the prototype of a mobile robot platform using two driving assemblies is given to prove the performance experimentally.

Dynamic Model and Control for a Holonomic Omnidirectional Mobile Robot

In the recent past, mobile robots with high mobility have been developed actively. We have already proposed a holonomic and omnidirectional mobile robot using two active dual-wheel caster assemblies and also derived the kinematic models for the assembly and the mobile robot. This paper presents dynamic analysis and control for the mobile robot. The dynamic model has been derived based on the forces acting on the steering axis. Then a model-based resolved acceleration controller is constructed. The validity of the model and the effectiveness of the control system are confirmed by experiments using a prototype robot as well as simulations.

Construction of an Omnidirectional Mobile Robot Platform Based on Active Dual-Wheel Caster Mechanisms and Development of a Control Simulator

In this paper, we describe a new type of holonomic and omnidirectional mobile robot using two driving assemblies, one of which consists of two independent driving wheel mechanisms, just like an active dual-wheel caster with an offset steered axis. Kinematic models of the wheel mechanism and a mobile robot with two driving assemblies are derived, and these models are applied to construct a feedback control system based on a resolved velocity control system for the robot. The effectiveness of the presented method is illustrated by some computer simulations. The prototype of a mobile robot platform using two driving assemblies, which can be controlled by a personal computer or a 3D joystick manipulated by human, is constructed.