NOVELTY - The system (100) has a body (103) made of shape memory material and housed in a brake caliper (101). An activation system (105) affects the shape memory material, effects change of a structure of the body of the shape memory material. The activation system comprises an electric heating element for heating the shape memory material. A controller (137) controls the activation system. A sensor (143) detects the change of the structure of the body of the shape memory material, and is communicatively coupled to the controller.    USE - Hydraulic/pneumatic braking system for braking a rotating brake disk of a wind turbine (claimed). Can also be used for braking a wheel of a vehicle i.e. car.    ADVANTAGE - The system ensures that the body of the shape memory material can be bent, so that the portion of the body of the shape memory material can bulge out or protrude to approach a brake disk surface and to apply force between a brake pad surface and the brake disk surface, thus providing braking function in an effective manner. The system enables sensor data to allow feedback to the controller to control the activation system based on desired braking effect and measured actual change of the structure of the body of the shape memory effect, thus facilitating operation of the system in a reliable and accurate manner. The system ensures that a fixed caliper does not move relative to the brake disk during operation, so that homogeneous or equal wear of the brake pad can be improved, thus simplifying maintenance of the system. The system ensures that the activation system is adapted to effect change of the structure of the body of shape memory material so as to reduce rotational speed of the brake disk.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a wind turbine.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of a hydraulic/pneumatic braking system including shape memory material.    Hydraulic/pneumatic braking system (100)    Brake caliper (101)    Body (103)    Activation system (105)    Brake disk (123)    Controller (137)    Sensor (143)