A patient support device, such as a bed, includes a frame, a backrest or other platform movable with respect to the frame, and an actuator connecting the backrest to the frame. The actuator is configured to raise and lower, or otherwise move, the backrest or platform with respect to the frame. An actuator sensor is provided to sense movement of the actuator. A backrest sensor is provided to sense movement of the backrest. A controller is coupled to the actuator, the actuator sensor, and the backrest sensor. The controller is configured to stop the actuator from raising the backrest in response to a characteristic signal from the actuator sensor. The controller is further configured to stop the actuator from lowering the backrest in response to at least a characteristic signal from the backrest sensor. The characteristic signals are defined to prevent the backrest or platform from moving when obstructed or overloaded in order to reduce the chance of damage or injury.
