To provide a control device and operation of an operation assisting device capable of reducing a deviation of a control amount due to a rotational torque acting on an arm member by an urging force of an urging member supporting a mounting member configured to be slidable with respect to an arm member An auxiliary device, and a method of controlling the motion assist device.An arm member that rotates around a joint portion, an actuator that generates a rotational torque of the arm member, and a control unit that controls the arm member so as to move the arm member toward the users body A sliding mechanism slidably connecting the arm member and the mounting member along a predetermined direction, and an urging member urging the mounting member toward the joint portion side The control device of the motion assist device includes an actuator control unit that controls the driving force of the actuator, and the actuator control unit controls the driving force of the actuator based on the biasing force of the biasing member.(FIG.【課題】アーム部材に対してスライド可能に構成された装着部材を支持する付勢部材の付勢力によってアーム部材に作用する回転トルクによる制御量のずれを低減可能な動作補助装置の制御装置及び動作補助装置並びに動作補助装置の制御方法を提供する。【解決手段】ユーザの所定の関節の側方に配置される関節部と、関節部を中心に回動するアーム部材と、アーム部材の回転トルクを生成するアクチュエータと、アーム部材をユーザの人体の所定の部位に取り付けるための装着部材と、アーム部材及び装着部材を所定の方向に沿ってスライド可能に連結するスライド機構と、装着部材を関節部側に付勢する付勢部材と、を備えた動作補助装置の制御装置は、アクチュエータの駆動力を制御するアクチュエータ制御部を備え、アクチュエータ制御部は、付勢部材の付勢力に基づいてアクチュエータの駆動力を制御する。【選択図】図7
