System and method for determining terrain transitions

A method of controlling the movement of a prosthetic ankle device attachable to a limb of a user, the prosthetic ankle device comprising a prosthetic foot, a lower limb member, and an actuator, the prosthetic foot being configured to pivot relative to the lower limb member and the actuator comprising a motor configured to provide for powered movement between the prosthetic foot and the lower limb member, the method comprising:

• operating the prosthetic ankle device on a first terrain, wherein said operating the prosthetic ankle device on the first terrain comprises adjusting the actuator in a first manner;
• monitoring with a sensor module located on the prosthetic ankle device an anticipatory change of a user during a stride prior to the user experiencing a terrain transition from the first terrain to a second terrain;
• processing data received from the sensor module to determine the terrain transition prior to the terrain transition being experienced by the user;
• and
• operating the prosthetic ankle device on the second terrain, wherein said operating the prosthetic ankle device on the second terrain comprises adjusting the actuator in a second manner different from the first manner based on the determined terrain transition.