There are basically three types of robot chassis, namely wheeled, tracked and walking. Chassis with wheels and tracks are the most common, walking robots are relatively rare, this section describes the design of ordinary wheeled robots and tracked robots.
Differential steering (or slip steering) is the most common type of steering for robots, in which two motors rotate in opposite directions to drive the robot to turn. We’ll talk about steering technology later.
The two wheeled robot is one of the simplest designs, with two wheels connected directly to a motor and some kind of skateboard used to help the robot balance. This kind of design actually works well in a variety of task environments, and in many cases, simple designs tend to do best.
Because the two wheeled robot’s wheels tend to be closer to the front, the robot’s center of gravity becomes a concern, and connecting arms to the robot may cause the robot to lean forward. So, as we add new features to the chassis, we’ll need to test it again and again to make sure your robot’s center of gravity isn’t off axis.
The tricycle robot is a very common lego robot design. A three-wheeled robot is similar to a two-wheeled robot, but it uses a Cardan wheel to help the robot balance, rather than a skateboard. The robot has two wheels connected to the motor, and a universal wheel at the rear, which automatically turns and travels in the robot’s direction. The cardan wheel balances the robot’s chassis and provides less friction than a skateboard.
A four-wheeled robot is more stable than a two-wheeled or three-wheeled robot. The four corners of the chassis each have a wheel, which provides a large supporting area for the center of gravity, ensuring the robot’s stability and not easy to lose balance. Differential steering for a four-wheeled robot is much more difficult than for a two-wheeled or three-wheeled robot, but this can be overcome with proper programming.
There are two types of four-wheel-drive robots, two-wheel-drive and four-wheel-drive.
The two-wheel-drive robot design is very similar to other robot designs, where two wheels are driven by a motor; the other two wheels are driven wheels, just to enhance the stability of the robot. Steering can be a challenge for a two-wheel-drive robot because one wheel can slip when the robot turns. If the wheels have good traction on the ground, there may be a lot of resistance when turning. Since the driven wheels don’t have power, they don’t need tires, so we can just use the hub, which slides around the field as the robot turns.
Four-wheel-drive robots are more complex, with two wheels on one side driven by a single motor and, in most cases, some gear. When we need a powerful robot or can climb a steep slope of the robot, four-wheel drive is very suitable. The four-wheel-drive robot turns in the same way as other differential-steering robots, but instead of just having two wheels to steer, its two wheels turn in one direction, the other two wheels turn in the other direction. The wheels will have some slippage, but all the wheels are turning, so we’re trying to minimize slippage. In addition, the closer the wheels are to each other, the less resistance they encounter when turning.
The tread of a tracked robot is similar to the tread of a wheeled robot, although it uses a set of lego tracks. The crawler gives the robot a very stable chassis with a low center of gravity. The undercarriage of a tracked robot is good at handling situations that span open or uneven surfaces.
Unfortunately, the disadvantages of using a caterpillar track often outweigh the advantages. The undercarriage of the tracked robot is difficult to travel in a straight line. It will beat on a smooth surface, and the smooth plastic will cause the track to lose traction quickly on the mission field, adding rubber parts to the track helps the robot move over a smooth surface. In addition, it is challenging to keep the track in proper tension. The third wheel in the track usually helps solve the tension problem, but does not improve the predictability of the track in completing the task.
If you like using a crawler, and it’s good enough to get the job done, we can give it a try. As the old saying goes, test it again and again to find the best fit.
Today, we talked about the most common chassis in robot design, hoping to help you make robots, choose a chassis, you can make a stable operation, accurate navigation robot.