Mobility assistance device and driving method therof

A mobility assistance device, comprising:

• at least one bracket;
• and
• a driving device, coupled to the at least one bracket,
• wherein the driving device comprises:
• a brushless direct current (DC) motor;
• a rotor angle sensor, sensing an angle of the brushless DC motor;
• and
• a sensing driver, coupled to the rotor angle sensor, and using a corresponding algorithm to estimate a corresponding angle corresponding to an angle velocity switching of the brushless DC motor, wherein the corresponding angle is used as an angle of the brushless DC motor, the sensing driver drives the brushless DC motor according to the corresponding angle, so that the brushless DC motor provides a supporting force to the at least one bracket,
• wherein the rotor angle sensor detects the angle of the brushless DC motor and generates a detection result, the sensing driver determines whether a current speed of the brushless DC motor exceeds a predetermined speed according to the detection result, thereby determining whether an angle velocity switching of the brushless DC motor occurs,
• wherein the corresponding algorithm comprises a Hall sensor angle compensation algorithm and a sensorless angle compensation algorithm, the Hall sensor angle compensation algorithm estimates a first angle based on the detection result of the brushless DC motor, and the sensorless angle compensation algorithm estimates a second angle based on a plurality of parameters and a power supply condition of the brushless DC motor,
• wherein the sensing driver further calculates a current angle error between the first angle and the second angle,
• the sensing driver determines whether the angle velocity switching of the brushless DC motor occurs, so as to determine whether to use the first angle obtained from the Hall sensor angle compensation algorithm or the second angle obtained from the sensorless angle compensation algorithm as the angle of the brushless DC motor, and drive the brushless DC motor according to the angle of the brushless DC motor,
• wherein when the current angle error is larger than a predetermined sensitivity or the current speed of the brushless DC motor does not exceed the predetermined speed, the sensing driver adopts the first angle obtained from the Hall sensor angle compensation algorithm as the angle of the brushless DC motor,
• when the current angle error is not larger than the predetermined sensitivity and the current speed of the brushless DC motor exceeds the predetermined speed, the sensing driver adopts the second angle obtained from the sensorless angle compensation algorithm as the angle of the brushless DC motor.