Engineers have been designing robots capable of climbing stairs for years, and while some have devised intricate platforms for accomplishing that task, others prefer a minimalist approach, such as UC San Diego’s SCR (Stair Climbing Robot), which uses a pair of wheels and a single leg to overcome obstacles, including steps.
The robot can conquer stairs using what the engineers term a MIP (Mobile Inverted Pendulum), which is planted just in front of a step. It then employs an actuator to lift the wheels onto the next and then retracts the MIP to start the process over again until it reaches the top. While in inverted mode, the SCR maintains balance by converting the drive wheels into reaction wheels- moving them back and forth to create a counter-balance to prevent tipping.
The SCR’s design is pretty simple in terms of complexity and features three body components- chassis, leg, and wheels, which are directly mounted to gear motors that are connected to the body. A timing belt and motor enable the body to travel up and down the leg and thus raise or lower the wheels to navigate uneven terrain.
Mounted inside both ends of the foot are cameras that let the operator see where the robot is traveling no matter what mode the SCR is configured for, including driving (leg is dragged behind the robot), MIP balancing (raised foot), leg balancing (wheels are lifted over the leg), and self-upright (transitioning from driving to balancing). The engineers state the SCR design is small and simple enough to be ruggedized for military and homeland security applications, although it could probably be used for search and rescue as well.