3-Wheel Head Robot Advantages

See 3-wheel standing robots, 2-wheel standing robots and 4-wheel standing robots

Advantages over 2-wheel designs

• Durability: 3 wheels can produce any type of spin without rotating the head. This means there is less stress to the head parts because there are no quick-start-and-stop actions to change spins as there would be with only 2 wheels. Less stress means parts will last longer. A small light Deflector Plate determines left/right and up/down throwing directions. This part can move very quickly because it is small and light. 2-wheel robots move the entire head left/right and up/down (as well as rotating up to 180 degrees), and that is a lot of weight and mass to move, which introduces more stress to the robot mechanics.
• Quicker change of spin: Without the need of a rotating head, change of spin can be accomplished in a shorter amount of time. This is critically important when you have two very different consecutive shots, such as a slow, heavy backspin/sidespin serve followed by a fast heavy topspin loop and you only have a few milliseconds to accomplish all this.
• Accuracy: The 3 wheels hold each ball in a much more secure position as it is being thrown. 2-wheel robots can allow the ball to slip sideways a little, which may result in less consistent throws.

Advantages over robots with 2 heads of 2-wheels each (4-wheel design)

• Single projection point: With 2 heads, players have to concentrate on two different projection points, something that does not happen in an actual game. This is especially true for any type of random delivery where balls are randomly thrown from 2 different points.
• Consistency: Let's say that for a 2-head robot, 1 head is set to throw topspin balls to point A and the other head is set to throw backspin balls to the same point. Since the balls are thrown from different angles, the player needs to position footwork for each head even if the landing point is meant the same.

Disadvantages over 2-wheel design robots

• Limited Choice: While there are several manufacturers producing 3-wheel designs, there are only 2 manufacturers known to us carrying a 3-wheel design robot.
• Price: 3-wheel design robots are generally more expensive than their 2-wheel/4-wheel counterparts.

Conclusion

A 3-wheel head design robot (Butterfly Amicus and Power Pong robots) can produce sessions with varying spin without having to rotate the entire head. This makes it possible to have training sessions with multiple spins at a high frequency. Robots with 2 heads of 2 wheels overcome this obstacle but introduce a new projection point that varies the angle at which balls are thrown at the player. As there are less moving parts, 3-wheel robots may last longer than 2-wheel robots.

See also

• Butterfly Robots
• Power Pong Robots