Robots as Spaceships: Responsive Movement

In our analysis of the Gunbot, we noticed two ways that robots could move. About half of them moved similar to humans, with a base move of 5 and a very similar top speed. They could move as far as they wanted in any direction, but they had a very low top speed. They moved like a person. The other Robots have very small base moves but much larger total moves. They took a few seconds to get up to speed. This sort of movement we will call "train-like".

Spaceships uses train-like movement, with the minor exception of leg systems, which start off person-like but get more train-like as leg systems are added. Its likely that both types of movement can be engineered and each will be engineered for different purposes.

Responsive Movement Factors

A spaceship motive system may be made more "responsive" by assigning it a responsive movement factor. The basic move of the motive system is multiplied by the factor its top speed is divided by that factor. Round to the closest whole number. If the adjusted basic speed is higher than the adjusted top speed, that responsive movement factor cannot be applied to that motive system.

For instance, a wheeled drivetrain might have a move of 6/60, but with responsive movement 1.5, it has an adjusted move of 9/40. Its basic move of 6 is multiplied by 1.5 for an adjusted basic move of 9, and its top speed of 60 is divided by 1.5 for an adjusted top speed of 40. With responsive movement 2, That same has a move of 12/30.  Or a tracked drivetrain might have move 1/10, but with responsive movement 2 that becomes 2/5.

Most Responsive Movement Factors are between 1.5 and 3. Most systems do not have a large enough ratio between their basic move and their top speed to apply responsive movement factors above 3. Numbers between 1.5 and 1 usually have a minimal effect. Applying a responsive movement factor of less than 1 is possible, but not recommended, and is probably abusive: the spaceship speeds are already optimized for high top speed.

Fully Responsive Systems

A motive system can be declared to be Fully Responsive. In this case, its base speed and its top speed will both be set equal to:

Square Root of (Old Base Speed * Old Top Speed)

Rounding normally. This mode is especially recommended for smaller robots and those intended for use indoors.

Fully Responsive Systems are a special case of responsive movement, and equal to what we would get if we applied the largest possible responsive movement  factor to a motive system

When To use These

Responsive movement is most suited for building robots limited to human speeds: basic moves too far above 15 can be problematic, and are likely to break suspense of disbelief, especially on the ground.

Genre is also plays a role in deciding when and where to use responsive movement factors. Often, stories require that robots move similarly to a human, or conversely demand that they move differently than humans.

I hope you find this a useful tool when building vehicles from spaceships, especially robots!