In nursing homes, repeatedly guiding several carereceivers in wheelchairs before and after meals is one of the factors that increase the burden on caregivers. A solution to this problem is to incorporate autonomous mobility functions into the wheelchair. Although many autonomous electric wheelchairs have been developed in the past, it is not reasonable to introduce them to all users of nursing homes from the standpoint of cost, charging, and maintenance. In this study, we are developing a detachable robot that can operate a manual wheelchair autonomously. The basic concept, target specifications, and design conditions are defined herein, and the results of basic experiments such as straight-line stability tests, obstacle sensor measurement tests, and self-position estimation are reported. The implementation of autonomous driving functions such as path generation and localization will be promoted in the future.