Abstract: A motor drive control device is capable of reducing gear rattling noise generated in a speed reducer without increasing size of the speed reducer and the number of components. A motor ECU controls a motor to generate a reverse set torque (Tn) when a target torque (T*) is reversed (at a time t1). The motor ECU sequentially calculates a backlash (B) in a counter gear mechanism, and sets a time period (D1) in which the reverse set torque (Tn) is generated by the motor and a time period (D2) in which a return set torque (Tp) is generated by the motor so that the backlash (B) at a current time becomes equal to a time integrated value (corresponding to an area A) of an estimated relative velocity (V2?V1) until a time of re-abutment.

Abstract: A motor drive control device is capable of reducing gear rattling noise generated in a speed reducer without increasing size of the speed reducer and the number of components. A motor ECU controls a motor to generate a reverse set torque (Tn) when a target torque (T*) is reversed (at a time t1). The motor ECU sequentially calculates a backlash (B) in a counter gear mechanism, and sets a time period (D1) in which the reverse set torque (Tn) is generated by the motor and a time period (D2) in which a return set torque (Tp) is generated by the motor so that the backlash (B) at a current time becomes equal to a time integrated value (corresponding to an area A) of an estimated relative velocity (V2?V1) until a time of reabutment.