Study on radiation induced performance degradation of BLDC motor in robot servo systems

Abstract

Humanoid robots have great potential in applications in organically dangerous environments, for example, in the radiation environments. However, the radiation damage on robot components except for electronic circuits has not been well studied. Our study in this paper is the first on the radiation induced performance degradation of the brushless DC (BLDC) motor in the robot servo systems. Based on the fact that radiation causes NdFeB magnet demagnetisation, we analyse how this demagnetisation would affect the BLDC motor performance by establishing a model introducing the demagnetisation factor into the electromagnetic model of the BLDC motor, and simulated the motor operation under open loop PWM control in MATLAB. The result shows that the radiation demagnetised BLDC motor will decrease in power, lose controllability, and even quit working by a 'magnetic-trap' jerking effect.