A motion producing device comprising an output member with a contact surface and a reference member. An actuator member is attached to the reference member, the actuator member having a traction surface and comprising actuator zones, each actuator zone being energizable to move a corresponding portion of the traction surface to change a contact state of the traction surface with the contact surface depending on an energized state of the actuator zone. An energy source is operatively coupled to the actuator zones for sequentially changing the energized state of the actuator zones. The actuator member provides a torque transmission path between the reference member and the output member.