Power Architecture

One of the biggest challenges in robot design is power management.

On one side, you need to provide enough power to the motors and electronics to ensure proper operation, but on the other hand, you need to manage heat dissipation and electric noise, which can affect the performance and reliability of the robot.

The TNY-360 robot tackles this challenge using two design choices.

1 - The power cascade

The TNY-360 draws a clear line between the "dirty" power used for the motors and the "clean" power used for the electronics.

And to limit the impact of Electro-Magnetic Interference (EMI) from the motors, the TNY-360 separates these power domains like a cascade across its body.

The main separation

These two power domains are connected at a single point, which is the main power input of the robot, where the battery is connected. This design respects the principle of Star Grounding in electronics, which helps to minimize noise and interference between the two domains.

flowchart TD
    Bat(Battery - 12.6v)

    subgraph Dirty ["Dirty Power"]
        DC7(Step-Down 7V 300W)
        Mot(MG996R)
    end

    subgraph Clean ["Clean Power"]
        DC5(Step-Down 5V 15W)
        PCB(ESP32, PCBs, ...)
    end

    Bat === DC7
    Bat === DC5
    DC7 === Mot
    DC5 === PCB

    style Dirty fill:#fd9a0020,stroke:#fd9a00,color:#fd9a00
    style Clean fill:#00a6f420,stroke:#00a6f4,color:#00a6f4

The cascade design

To limit the impact of EMI from the motors, the TNY-360 separates these power domains like a cascade across its body.

The battery is located on the bottom of the robot, with its connector plugged at the rear of the robot, which is the main power input.

This 12.6V power is then distributed across the body in stages, going from high-power and high-noise components at the back (like the motors) to low-power and low-noise components at the front (like the microcontroller).

flowchart RL
    %% On définit les zones physiques du robot
    
    subgraph Front ["Front (low power & noise)"]
        direction LR
        LDO("LDO 3.3V") === ESP("ESP32 & Sensors")
    end

    subgraph Center ["Center (medium power & noise)"]
        DC5("Step-Down 5V 15W")
    end

    subgraph Back ["Back (high power & noise)"]
        direction LR
        DC7("Step-Down 7V 300W") === Mot("MG996R")
    end

    Power("Power board")

    subgraph Belly ["Belly (Battery)"]
        Bat("Battery - 12.6V")
    end

    Power === DC7
    Power === DC5
    DC5 === LDO
    Bat ===|XT30| Power

    style Front fill:#00c95120,stroke:#00c951,color:#00c951
    style Center fill:#fd9a0020,stroke:#fd9a00,color:#fd9a00
    style Back fill:#fb2c3620,stroke:#fb2c36,color:#fb2c36
    style Belly fill:#00a6f420,stroke:#00a6f4,color:#00a6f4

This cascade design helps to limit the impact of EMI and voltage fluctuations from the motors on the sensitive electronics, while also allowing for efficient power distribution across the robot.