Turning control device

A turning control device for controlling a turning apparatus as a controlled object, the turning apparatus including

• a steering wheel,
• an input shaft connected to the steering wheel,
• an intermediate shaft,
• an output shaft,
• a first Cardan joint connecting the input shaft to the intermediate shaft,
• a second Cardan joint connecting the intermediate shaft to the output shaft,
• steered wheels configured to receive a steering torque input into the steering wheel, via the input shaft, the intermediate shaft, and the output shaft, and
• an assist motor configured to give a torque to a position closer to the steered wheels than the second Cardan joint, the turning control device comprising (i) a storage device in which mapping data is stored and (ii) a control device configured to execute following processes:
• a torque acquisition process of acquiring a detection value of a torque applied to the position closer to the steered wheels than the second Cardan joint;
• a steering angle variable acquisition process of acquiring a value of a steering angle variable indicative of a steering angle as an angle of the steering wheel;
• and
• an assist control process including a fluctuation torque control process of fluctuating the torque of the assist motor in accordance with the steering angle with the value of the steering angle variable being taken as an input, wherein:
• the steering angle variable acquisition process is a process of acquiring a value of a variable indicative of a rotation angle of the output shaft as the value of the steering angle variable;
• the mapping data is data defining a mapping to output the steering angle with the value of the steering angle variable being taken as an input;
• and
• the assist control process includes a steering angle calculation process of calculating the steering angle by inputting the value of the steering angle variable into the mapping.