Mike's Lego Robots Page
Below are some of the LEGO robots I have built from the LEGO Mindstorms RIS 2.0. I got hooked on LEGO technic when I was about 8 and have been building all sorts of things with them ever since. When designing most of my other robots (Mechadon, MiniMechadon, Hexapod), I have made the first prototypes out of LEGO.
Biped2 uses parts from the Mindstorms RIS 2.0 and the #8455 Back-hoe Loader kit. The air tank on the top is a 500mL water bottle with an air fitting installed in the lid. Other than this and a couple hoses, all the parts are LEGO. I could have used several LEGO air tanks, but I don't have any (this is my only complaint about the 8455 Back-hoe kit - 10 cylinders, 7 valves and NO airtank.) I ran out of long hoses, so I had to use a couple pieces of vinyl tubing from the local hardware store. Nothing is special about the function of the non-LEGO parts that were used - I just didn't have quite enough of the official LEGO pieces.
Biped2 uses all pneumatics for walking - 6 cylinders in all. There is also a cylinder to bend each knee, but it turned out that it didn't need these to walk so I just hooked them up to keep the knees extended when pressure is applied to the system. The walking motion is controlled entirely by air logic. When a cylinder moves part of the robot, it also moves a valve. This redirects air pressure to another cylinder, which moves another part of the robot and another valve, etc... The result is the cyclic walking motion shown in the video below. The programmable brick was not used on this design. There is also no motor, batteries or pump on-board the robot. With the fill valve in the down position, the air tank is pumped up using the two pumps that came with the 8455 kit. The valve is then returned to center and the pumps can be disconnected. When the fill valve is in the UP position, pressure from the tank is applied to the air logic and the robot begins to walk. If there is too much pressure in the tank, the cylinders act too quickly and the robot has a tendency to fall over. I found that with 130 pumps (using two pumps in parallel) the robot would take several steps before running out of pressure and it rarely falls over.
This video shows the robot in action.
Biped1 uses only the parts that come with the Mindstorms RIS 2.0. One motor moves both legs fore-aft and the other rotates the ankles laterally. There is a touch switch on each foot that detects when the robot is leaning far enough to swing the other leg forward. The light sensor is mounted so it points toward the front vertical bar of the right leg. The intent was to sense the fore-aft position of the legs to improve walking consistency.
BIPED1 - Video of BIPED1 walking on my workbench.
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