Tire ground contact characteristic measuring method, tire ground contact characteristic measuring portion, and tire ground contact characteristic measuring system

A tire ground contact characteristic measuring system comprising:

• a tire ground contact characteristic measuring portion;
• a vehicle characteristic measurer;
• and
• an actual vehicle behavior simulator,
• wherein the tire ground contact characteristic measuring portion includes:
• a rotatable rotary drum;
• a drum driver that rotationally drives the rotary drum;
• a stress measurer that is embedded on the rotary drum and measures stress applied to a tire in contact with the rotary drum;
• a tire position controller that controls a position of the tire with respect to the rotary drum;
• a tire driver that rotationally drives the tire;
• a tire angle controller that controls an angle of the tire with respect to the rotary drum;
• a tire pressure changer that adjusts air pressure of the tire;
• and
• a processor that calculates tire ground contact characteristics, which are characteristics of a ground contact region of a tread surface of the tire in contact with the rotary drum, on the basis of the stress measured by the stress measurer,
• wherein the drum driver, the tire position controller, the tire driver, the tire angle controller, and the tire pressure changer operate to reproduce a transient change in a tire attitude that occurs during travel of an actual vehicle on the tire,
• the processor calculates the tire ground contact characteristics corresponding to the tire attitude of the actual vehicle at each point in time during a period where the transient change occurs,
• wherein the drum driver can adjust a rotational speed of the rotary drum,
• the tire position controller can adjust the position of the tire with respect to the rotary drum in a direction of an axis of rotation and/or a radial direction of the rotary drum,
• the tire driver can adjust a rotational speed of the tire,
• the tire angle controller can adjust a camber angle, a slip angle, and/or a grip force of the tire,
• the tire pressure changer can adjust the air pressure of the tire,
• the drum driver, the tire position controller, the tire driver, and the tire angle controller are operated during the period where the transient change occurs in order to reproduce the transient change in the tire attitude of the actual vehicle on the tire,
• the tire angle controller continuously changes the camber angle, the slip angle, and the grip force to be given to the tire with a passage of time from a start to an end during the period where the transient change occurs,
• the stress measuring sensor continuously measures stress applied to the tire at least for each rotation of the rotary drum from the start to the end during the period where the transient change occurs,
• the vehicle characteristic measurer includes a test vehicle that includes a vehicle body and a wheel, a mount, and a controller,
• the mount includes a supporter on which the test vehicle is to be placed and a measurer,
• the supporter independently displaces the vehicle body and the wheel,
• the measurer measures an amount of displacement and/or an acting force of the vehicle body and an amount of displacement and/or an acting force of the wheel,
• the controller controls the amount of displacement to be given to the vehicle body by the supporter and the amount of displacement to be given to the wheel by the supporter, and
• the processor predicts a motion state of the actual vehicle during travel by using measurement data of the measurer and reproduces the transient change in the tire attitude on the tire on the basis of the predicted motion state,
• the vehicle characteristic measurer reflects vehicle characteristics, which are predicted from the tire ground contact characteristics calculated by the processor, in the test vehicle,
• the measurer measures the amounts of displacement and/or the acting forces of the vehicle body and the wheel of the test vehicle in which the vehicle characteristics are reflected, and
• at least one of a change of a rotational speed of the rotary drum performed by the drum driver, a change of a position of the tire with respect to the rotary drum performed by the tire position controller, a change of a rotational speed of the tire performed by the tire driver, and a change of an angle of the tire performed by the tire angle controller is performed on the basis of measurement data of the measurer in which the vehicle characteristics are reflected.