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Besiege Notes on Automation Block Stabilization #2 --- Bike, Car & Ekranoplan Implementations

Automation block balanced motorcycle


This series of articles document how my approximated automation-block PID controller works and how I implement them on self-stabilizing machines.

Proportional Controller on Bikes

For a motorcycle to self balance, a P controller is a must. A simple 2 sensor and reaction wheel will make a motorcycle oscillate badly.
To build a vanilla self-balancing bike, the mechanism has to be small. I chose to fit this gyroscope system in the bike shown in the picture. As the spinning-block-powered contra-rotating gyroscope spins, the torque is canceled. However if the axes of rotation of the two gyroscopes are not aligned perfectly, a net torque is generated and increases as the angle between the axes of rotation gets bigger.

The two spinning blocks on steering hinges provides torque to balance the motorcycle, and the 2-anglometer angle tracker is synchronized with one of the 2 hinges. Another hinge is used to tilt the motorcycle

The generated torque isn't linear to the angle, but sinusoidal. This is ideal when the angle is small. The output is approximately linear if the gyroscopes spin fast to provide enough torque at small angle differences. This makes it a P controller for tilt angle correction.
A note on this mechanism is that the gyroscopes themselves are strong enough to act as damper. Although the motorcycle still oscillates, with a bit of tuning it doesn't oscillate badly with the absence of term D. If  it is a modded machine built with scaling, an active damper can be added.

Active damper, a D controller with 2-anglometer angle tracker and a reaction wheel

Derivative Controller on Cars, and Fly-by-Wire Systems

If you know a little of cars and planes, you might know the idea of fly-by-wire systems. In this experiment, an angle tracker is on a steering block that mapped to the keyboard input. and the output mapped to the RTC steering system of the car. It creates a stabilized steering experience on drifty Besiege cars. The system corrects the over steering automatically.

Fly by wire steering, the car automatically flicks the wheel after power sliding

Putting the tracker on another steering hinge/block that the user controls creates a fly-by-wire system. The gif below shows a VTOL test bed implemented with PD controller for pitch and roll, and a D controller for yaw. On this particular plane the user controls the nozzle vectoring for moving forward and backward. The roll and yaw are fly-by-wire.

PD stabilized system on Redstoneman's VTOL test bed
The PD controller for angle used in the test bed above. Consists of a 2-anglometer angle tracker, a flying block pair and a reaction wheel

Ekranoplan

Before jumping into hovering sci-fi vehicles, I'll introduce my Ekranoplan system.
It uses two P controllers for height to emulate the ground effect on each wing, and a P controller for height to change the lift from the propeller blocks and control the elevators. The system again does not have the D term. One is because I haven't found how to build a D controller back then, two is the drag from the aerodynamic blocks dampen the height change pretty well.

Ekranoplan test bed

In the next article I'll show the choices i made to implement PD controllers into my hover car to efficiently deliver the performance I wanted.
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Besiege Notes on Automation Block Stabilization #1 --- PID Controller

This series of articles document how my approximated automation-block PID controller works and how I implement them on self-stabilizing machines.

Trackers and Steering Hinge SyncingTo see the sensor beams in simulation, The Colliderscope mod Must be installed. Other mods from Dagirefaa are also recommended for advanced building.
The stabilization systems I developed is based on trackers and steering hinge/block synchronization. Either a single-sensor version with RTC steering hinge, or a 2-sensor non RTC version will do the job. The same idea can be applied to absolute angle tracking with anglometer blocks. And again, in my notes I assume the readers have a certain understanding in Besiege building to replicate these just by a glance.


To make the tracking useful, I need to utilize the angle of the steering hinge. Since the steering hinges/blocks are perfectly synced when bound to the same keys, I can set up a system that has continuous output instead of "0 and 1".


PID Contr…

Besiege Notes on Propeller Engines

Kuroko (thesencoredstudio) from Steam requested a talk about propeller engines.

There are a few things you can do to get the most potential out of propeller engines. I suppose the reader knows some advanced stuffs like Besiege plane building experiences and flatangle propeller blocks, also basic aeronautics .

The Angle of Attack (AoA) The 90° flatangle is ideal if the plane is going to fly supersonic, but I recently build only 1:1 scale WWII fighter planes with top speed below 200 m/s. 75° to 80° AoA is what I usually use.

The Radius I follow the specifications when I build replicas. If its an original aircraft, it is of course the bigger the better.

The Number of Propeller Blocks In Besiege, the propeller blades are made of propeller blocks, the vertical and horizontal stabilizers are also made of propeller blocks. It'd be an un-flyable plane when the stabilizing effect of the propeller is stronger than the tail's. Remember to add propeller blocks to the tail when making a dou…