An object of the present invention is to prevent unnecessary driving stop of a stepping motor. A robot arm section includes a robot arm, a stepping motor 31a, a motor driver 31b, an encoder 31c and a step-out detection section 31e. The robot arm has a joint J1. The stepping motor generates power for operating the joint. The motor driver drives the stepping motor according to a target angle. The encoder outputs an encoder pulse every time a drive shaft of the stepping motor rotates by a predetermined angle. The step-out detection section detects a step-out of the stepping motor based on the target angle and a current angle of the stepping motor that is identified based on the encoder pulse. When the stepping motor does not recover from the step-out before a predetermined grace time elapses from a time at which the step-out is detected, the motor driver stops driving the stepping motor at the time point at which the grace time elapses.

An object of the present invention is to prevent unnecessary driving stop of a stepping motor. A robot arm section includes a robot arm, a stepping motor 31a, a motor driver 31b, an encoder 31c and a step-out detection section 31e. The robot arm has a joint J1. The stepping motor generates power for operating the joint. The motor driver drives the stepping motor according to a target angle. The encoder outputs an encoder pulse every time a drive shaft of the stepping motor rotates by a predetermined angle. The step-out detection section detects a step-out of the stepping motor based on the target angle and a current angle of the stepping motor that is identified based on the encoder pulse. When the stepping motor does not recover from the step-out before a predetermined grace time elapses from a time at which the step-out is detected, the motor driver stops driving the stepping motor at the time point at which the grace time elapses.

A driving processor for driving a motor having a rotor and one or more coils for rotating the rotor is configured to generate a detection pulse for detecting whether or not the rotor has rotated; cause the generated detection pulse to be applied to at least one of the one or more coils; receive a signal indicating a detected value of current flowing in the at least one of the one or more coils after the detection pulse has been outputted to the at least one of the one or more coils; and determine whether or not the rotor has rotated to one or more prescribed positions on the basis of the detected value of current.

A driving processor for driving a motor having a rotor and one or more coils for rotating the rotor is configured to generate a detection pulse for detecting whether or not the rotor has rotated; cause the generated detection pulse to be applied to at least one of the one or more coils; receive a signal indicating a detected value of current flowing in the at least one of the one or more coils after the detection pulse has been outputted to the at least one of the one or more coils; and determine whether or not the rotor has rotated to one or more prescribed positions on the basis of the detected value of current.

A driving device includes a stepping motor having a rotor, a coil for rotating the rotor, and a processor that drives the stepping motor. The processor generates a driving pulse for rotating the rotor of the stepping motor to a prescribed position, and outputs the driving pulse to the coil; and generates a rotation assistance pulse for rotating the rotor of the stepping motor at a prescribed speed, and outputs the rotation assistance pulse to the coil, after outputting the driving pulse but before EMF is produced by the rotation of the rotor of the stepping motor caused by the driving pulse.

A driving device includes a stepping motor having a rotor, a coil for rotating the rotor, and a processor that drives the stepping motor. The processor generates a driving pulse for rotating the rotor of the stepping motor to a prescribed position, and outputs the driving pulse to the coil; and generates a rotation assistance pulse for rotating the rotor of the stepping motor at a prescribed speed, and outputs the rotation assistance pulse to the coil, after outputting the driving pulse but before EMF is produced by the rotation of the rotor of the stepping motor caused by the driving pulse.

According to one embodiment, a controller of a stepping motor includes a table generating unit and a current controlling unit. The table generating unit generates a data table of a threshold by using values of induced voltage at frequencies of switching signal that changes a set value of a drive current, the threshold being proportional to a frequency of the switching signal within an operation region in which the frequency of the switching signal is lower than a predetermined frequency, the values of the induced voltage including a first induced voltage generated at a first frequency of the switching signal and a second induced voltage generated at a second frequency of the switching signal. The current controlling unit controls a value of the drive current in accordance with a comparison result between the threshold and an induced voltage that is detected at a frequency lower than the predetermined frequency.

According to one embodiment, a controller of a stepping motor includes a table generating unit and a current controlling unit. The table generating unit generates a data table of a threshold by using values of induced voltage at frequencies of switching signal that changes a set value of a drive current, the threshold being proportional to a frequency of the switching signal within an operation region in which the frequency of the switching signal is lower than a predetermined frequency, the values of the induced voltage including a first induced voltage generated at a first frequency of the switching signal and a second induced voltage generated at a second frequency of the switching signal. The current controlling unit controls a value of the drive current in accordance with a comparison result between the threshold and an induced voltage that is detected at a frequency lower than the predetermined frequency.

A control unit is configured to determine a first parameter from a back EMF signal, and to determine at least one second parameter from the back EMF signal corresponding to the first parameter. The control unit verifies, based on the first parameter, at least one condition containing the at least one second parameter, and detects stall or step-loss in the stepper motor based on the verification. The control unit uses a pattern detection by identifying characteristic features of peaks of the back EMF signal, which are order, magnitude and polarity. These characteristic features are independent of RPM, backlash, load and do not require complex calculations and are very robust even at lower RPMs.

A control unit is configured to determine a first parameter from a back EMF signal, and to determine at least one second parameter from the back EMF signal corresponding to the first parameter. The control unit verifies, based on the first parameter, at least one condition containing the at least one second parameter, and detects stall or step-loss in the stepper motor based on the verification. The control unit uses a pattern detection by identifying characteristic features of peaks of the back EMF signal, which are order, magnitude and polarity. These characteristic features are independent of RPM, backlash, load and do not require complex calculations and are very robust even at lower RPMs.