Vehicle travel control device

A vehicle travel control device that controls travel of a vehicle, comprising:

• a sensor configured to detect a travel state of the vehicle;
• and
• a control device configured to execute trajectory following control that generates a target trajectory and controls travel of the vehicle such that the vehicle follows the target trajectory, wherein
• a delay time is a time representing control delay of the trajectory following control,
• a delay compensation time is at least a part of the delay time,
• the trajectory following control comprises:
• information acquisition processing that acquires sensor-detected information indicating a result of detection by the sensor;
• displacement estimation processing that estimates a displacement of the vehicle in the delay compensation time based on the sensor-detected information;
• delay compensation processing that corrects a deviation between the vehicle and the target trajectory based on the estimated displacement to compensate the control delay;
• and
• travel control processing that controls the travel of the vehicle such that the deviation decreases after the delay compensation processing,
• the control device is further configured to determine an effective period in which the displacement estimation processing is effective and an ineffective period in which the displacement estimation processing is ineffective, wherein determining the effective period and the ineffective period is based on at least one of a functioning state of the sensor and the sensor-detected information,
• when the ineffective period is included in the delay time of the trajectory following control, the control device executes the displacement estimation processing in a temporary mode, and
• in the temporary mode, the control device executes the displacement estimation processing by using at least the sensor-detected information in the effective period without using the sensor-detected information in the ineffective period.