Control device and control method for variable valve timing mechanism

A control device of a variable valve timing mechanism that makes a rotational phase of a camshaft variable relative to a crankshaft of an internal combustion engine by adjusting rotation of a motor, the control device being configured to:

• obtain information on a rotational angle of the motor, information on a rotational angle of the crankshaft, and information on a rotational angle of the camshaft;
• obtain a first measurement of the rotational phase based on the rotational angle of the motor;
• obtain a second measurement of the rotational phase based on a relative relationship between the rotational angle of the crankshaft and the rotational angle of the camshaft;
• calibrate the first measurement based on the second measurement;
• obtain a derivative term proportional to a rate of change in a deviation between the first measurement and a target value of the rotational phase;
• reduce change in derivative term when calibrating the first measurement based on the second measurement;
• obtain a manipulated variable of the motor based on the derivative term;
• and
• control the motor based on the manipulated variable.