Mechanical Design of "Omni-Ball": Spherical Wheel for Holonomic Omnidirectional Motion

2013 IEEE International Conference on Robotics and Biomimetics (ROBIO)

2013

This paper presents a predictive kinematic control method for a three-wheeled omnidirectional mobile robot on the basis of MY wheel-II assemblies. Firstly, the kinematic analysis is conducted, which shows that eight possible models can be employed in the controller to produce the desired motor velocity for servo motors. Then for each finite fixed prediction horizon, a predictive control strategy is proposed to select the optimal model from the eight possible models. The key idea is that, for each finite fixed prediction horizon, the future value of a cost function is estimated for all the eight possible models. The model which minimizes the cost function is selected. Several simulations have been conducted to verify the effectiveness of the proposed control method. It shows that the proposed control method achieves definitely better performance than a previous proposed control method using an average model to produce the desired motor velocity.

Section: Simulationssupporting

confidence: 57%

Section: Kinematic Analysismentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Predictive kinematic control of an omnidirectional mobile robot

2013 IEEE International Conference on Robotics and Biomimetics (ROBIO)

2013

“…Omnidirectional non-switch wheels include wheels such as Mecanum wheel, [2] Alternate wheel [3] and Ball wheel. [4][5][6] The dynamics of non-switch-wheeled OMRs are smooth and non-linear, because the contact radius is constant. On the other hand, by far, the proposed switch wheels are shown in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

A continuous dynamic modeling approach for an omnidirectional mobile robot

Sun

et al. 2015

Advanced Robotics

MY wheel-II is one of switch omnidirectional wheel mechanisms. The omnidirectional mobile robot based on MY wheels-II is a switched non-linear system (i.e. discontinuous system). The aim of this paper is to propose a continuous modeling approach which can be employed to derive a continuous model from any given discontinuous robot dynamic model. This approach results in a continuous non-linear parameter varying (NLPV) model, and offers one solution for model-based control design. Firstly, our previously proposed average dynamic modeling approach is analyzed. We find that this modeling approach is effective only for a specific class of robot configurations. To overcome this problem, we first derive the switching conditions of MY wheel-II. Based on derived switching conditions, we then propose a simple continuous NLPV modeling approach. The new approach replaces the real discontinuous contact radius in the discontinuous dynamic model with an adaptive continuous curve. An illustrative example of the adaptive continuous curve design is provided. Both simulation and experimental results verify the effectiveness of the proposed NLPV modeling approach against the average modeling approach.

“…These mechanisms can be divided into two groups: non-switch wheels and switch wheels, depending on whether the contact radius of the wheel to the robot gravity center switches. Majority of the wheels, such as Mecanum wheel [1], Alternate wheel [2] and Ball wheel [3], are of the first group. The five switch wheel mechanisms proposed until now are shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Dynamic modeling and analysis of an omnidirectional mobile robot

2013 IEEE/RSJ International Conference on Intelligent Robots and Systems

2013

This paper presents the dynamic modeling and analysis of a three-wheeled omnidirectional mobile robot with MY wheels-II, whose dynamics is nonlinear and piecewisesmooth. Firstly, the detailed dynamic model of the robot is derived, which shows that the robot is actually a switched nonlinear system. Analysis of the robot dynamic properties based on the detailed dynamic model is presented in detail. Then to facilitate the controller design for the switched nonlinear system, based on the detailed dynamic model, an average dynamic model is proposed by simply averaging the wheel contact radius. The resulting average dynamic model is nonlinear and smooth, which may then be used as one solution for the model-based control design. Open-loop simulation results show the dynamic properties of the mobile robot. In addition, the effectiveness of the proposed average model in predicting characteristics of the detailed dynamic model is also illustrated through open-loop simulations.