By utilizing the analytical magnetic field model, the actuator torque caused by the interaction between current carrying coils and the magnetic field of the PM-pole rotor is formulated based on Lorentz force law. This torque model relates the torque output of the spherical actuator to the current inputs of coils and the rotor orientation, which indicates that the torque output of the PM spherical actuator is orientation dependant. Nonsingularity is one of the important advantages of the PM spherical actuator. Based on the torque model, existence of inverse electromagnetics solution or nonsingularity workspace of the PM spherical actuator is verified through the condition numbers of the torque matrix. In addition, the minimum right-inverse electromagnetics solution is proposed to calculate the required current inputs for desired torque output. This solution can minimize the electric power consumption of the spherical actuator. The linear torque model can facilitate the real-time motion control of the actuator. It can also be used for the spherical actuator design to maximize the actuator torque output.
KeywordsCondition Number Current Input Torque Output Electric Power Consumption Switch Reluctance Motor
Unable to display preview. Download preview PDF.
- 1.Gieras J F, Wing M et al (1998) Permanent Magnet Motor Technology. Marcel Dekker, Inc., New York, USA, 1998. Google Scholar
- 6.Krause P C, Wasynczuk O et al (1989) Electromechanical Motion Devices. McGraw-Hill, Inc., USA, 1989. Google Scholar
- 8.Lee K M, Sosseh R A et al (2002) Effects of the Torque Model on the Control of a VR Spherical Motor. Proceedings of the 2nd IFAC Conference on Mechatronic Systems, Berkeley, California, USA, 9–11 December 2002. Google Scholar
- 9.Roth R B (1992) An Experimental Investigation and Optimization of a Variable Reluctance Spherical Motor. Thesis of Georgia Institute of Technology, GA, USA, 1992. Google Scholar
- 10.Sahoo S K, Zheng Q, Panda S K, Xu J X et al (2003) Model-based torque estimator for switched reluctance motors. Proceedings of The Fifth International Conference on Power Electronics and Drive Systems, PEDS, vol. 2:959–963, Singapore, 17–20 November 2003. Google Scholar
- 11.Materu P, Krishnan R et al (1990) Analytical prediction of SRM inductance profile and steady-state average torque. Conference Record of the 1990 IEEE Industry Applications Society Annual Meeting, vol. 1:214–223, Seattle, WA, USA, 7–12 October 1990. Google Scholar
- 12.Sadiku N O M (2001) Elements of Electromagnetics. Oxford University Press, UK, 2001. Google Scholar
- 18.Griffel D H (1989) Linear Algebra and Its Applications. Ellis Horwood Limited, UK, 1989. Google Scholar
- 19.Nakamura Y (1991) Advanced Robotics: Redundancy and Optimization. Addision-Wesley Publishing Company, USA, 1991. Google Scholar
- 20.Zhou Z (1995) Real-Time Control and Characterization of a Variable Reluctance Spherical Motor. Thesis of Georgia Institute of Technology, GA, USA, May 1995. Google Scholar