<p>The problem of caring for the disabled has gradually increased the economic burden on families and the state. However, most existing energy storage exoskeletons use passive mechanisms or are driven by motors. To improve the power density and dynamic response speed of the ankle exoskeleton, this paper uses shape memory alloy (SMA) wire as energy storage driving components while considering the influence of load dynamics in the control system. The ankle exoskeleton assists the human ankle in compressing the bias spring through SMA. When the human ankle needs assistance, SMA releases the energy stored by the bias spring and transmits the energy to the ankle exoskeleton to achieve the effect of assisting the human ankle. During the assistance process, this article considers the impact of load dynamics on the control system and constructs a feedforward controller based on bias spring dynamics. During the experiment, this energy storage ankle exoskeleton can achieve 0.5 Hz position actuation bandwidth at 4 mm amplitude, effectively complete the movement state of upstairs, squatting, and walking, provide effective power 150 N, store maximum energy 4.418 J for the human ankle effectively, and reduce ankle muscle output. The above ideas provide a new approach for further expanding power density and can be widely applied in the field of robotics.</p>