Big Dog is a four legged robot that was built by Boston Dynamics. It is roughly the size of a small mule, with a length of 3 feet and a height of 2.5 feet. The main purpose behind building Big Dog was so that it could be used in battlezones to transport weapons as well as rations from one place to another, through routes that weren't traversible using conventional transport methods. As a result, Big Dog was designed to carry a weight of upto 150 kilograms and still run at a speed of 4mph.
Big Dog has approximately 50 sensors installed, which perform a variety of tasks. Some sensors measure the force and motion at the joints, while others measure inertia, acceleration and other physical parameters. Big Dog even has sensors to monitor the internal functioning of the robot, such as temperature, hydraulic pressure and engine speed, among other things. Thus, there is a lot of data that the robot is processing at every instant. This counts as the sense portion of the robot
All this data is sent to an on-board local computer, which processes the data to determine what terrain the robot is travelling on. This is done even though the robot doesn't have sensors that determine the state of the external environment. Based on what the computer predicts the terrain is, it plans how the robot should walk to traverse the terrain. This planning is then sent to the motors & actuators in the limbs of Big Dog.
Overall this robot is a very good example of sense, plan & act.