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LAB 11- Motors and Controls

Overview

In this lab, we simulated and assembled the avionics, control systems, and propulsion components used in the Believer. The objective was to properly power, arm, configure, and verify each subsystem—including the DATX transmitter, Cube flight controller, receiver, servos, motors, and ESCs—ensuring that the aircraft can be safely commanded and controlled.

The lab consisted of four major parts:

DATX Setup Calibration, binding, and configuration of the radio system, including CRSF/SBUS verification and LUA script parameter setup.

Avionics Setup Creating a mock-up of the Believer aircraft avionics by connecting all sensors to the Cube, verifying system health in GCS, and mapping all RC inputs and servo outputs using RCMAP and SERVO#_FUNCTION tables.

Motor and Control Setup Physically connecting motors, ESCs, and servos to the Cube, testing signal routing, and performing full ESC calibration with a throttle ramp-up.

Wiring Diagram Update Updating the team wiring diagram using the verified connections and parameter mapping from the lab.

This lab emphasized safe powering procedures—including always pinning throttle and treating an armed aircraft as live—as well as attention to parameter correctness, robust radio configuration, and verification through physical testing.

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Part 1 – DATX Setup

Questions

1. What is CRSF and SBUS? What are the differences?

SBUS is a serial bus protocol commonly used in RC systems. It provides simplicity, broad compatibility, and stable performance.

CRSF (Crossfire) is a high-performance radio protocol developed by Team BlackSheep. It offers:

Lower latency

Higher update rates

Better link reliability

Greater range

However, CRSF is more complex and requires compatible hardware, while SBUS is more universal but slower.

2. What is Multi-Bind on the TBS Tracer?

Multi-Bind allows a single transmitter to bind to multiple receivers simultaneously. This enables the pilot to switch between different aircraft without re-binding for each one.

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DATX Configuration Tasks

Powered on the DATX.

Observed stick movement and verified axis detection.

Navigated to Hardware => Sticks Calibration and performed full stick calibration.

Verified stick response on the home screen.

Opened the LUA script => Tracer Micro TX.

Ensured Multi-Bind => Enabled.

Connected the receiver (RX) to the Cube and powered the system.

Returned to LUA script => selected Tracer Nano RX.

Opened Output Map and verified that Channel 1 = SBUS.

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Part 2 – Avionics Setup

Avionics Mock-up and System Check

Connected all relevant sensors to the Cube based on prior labs.

Connected the FCU to the GCS and verified system health.

GCS Platform Health Screenshot

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RCMAP_X Table

Table 9

Table 9

Name

Setting

RCMAP_BRAKE

RCMAP_FLAP

RCMAP_PITCH

RCMAP_ROLL

RCMAP_THROTTLE

RCMAP_YAW

There are no rows in this table

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SERVO#_FUNCTION Table

Table 10

Table 10

Name

Setting

SERVO1_FUNCTION

FlaperonRight

SERVO2_FUNCTION

FlaperonLeft

SERVO3_FUNCTION

Throttle

SERVO4_FUNCTION

Throttle

SERVO5_FUNCTION

VTailLeft

SERVO6_FUNCTION

VTailRight

SERVO7_FUNCTION

Rudder

There are no rows in this table

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DATX → Servo Output Mapping Table

Table 11

Table 11

DATX Control Input

Primary Servo Output

Secondary Output

Additional Notes

Right Stick

FlaperonRight

FlaperonLeft

Also affects both V-Tail surfaces for pitch/roll mixing

Left Stick

Throttle (SERVO3 & SERVO4)

VTailLeft & VTailRight

Rudder also active through yaw mixing

There are no rows in this table

⁠

This table demonstrates how each stick input influences multiple control surfaces based on the aircraft’s mixing configuration.

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Part 3 – Motor and Control Setup

Questions

1. What does the RCMAP_X parameter control?

RCMAP parameters determine which RC input channel corresponds to each control function (Roll, Pitch, Yaw, Throttle, Flaps, etc.). They map transmitter channels to Cube inputs.

2. What does SERVO#_FUNCTION control?

SERVO#_FUNCTION assigns each physical output pin on the Cube’s servo rail to a specific aircraft control function (flaperon, throttle, V-tail, rudder). This determines what each servo actually does.

3. Power sources for:

Servos: Powered through BECs from the battery.

Motor: Powered directly from ESC => Battery, sometimes through a BEC depending on ESC type.

Cube/FCU: Powered through a regulated input such as Power Module or BEC connected to the battery.

⁠

Motor and Control Setup Tasks

Retrieved two ESCs, two motors, and four servos.

Connected one servo to the FlaperonRight output and one ESC to the Throttle output using the tables above.

Instructor signoff: 👍

Tested servo movement: No movement initially (expected, because BEC power was not yet available).

Connected ESC to thrust stand and applied power.

Photo not put in group lab document of setup :(

Retested servo movement: Servo now responded correctly because the ESC’s BEC supplied power to the servo rail.

Located the ESC Calibration Guide.

Performed ESC calibration with modifications:

Aircraft in Manual Mode

Aircraft Armed in GCS (motor can spin—safety critical)

Followed manufacturer’s high-throttle => power-on => tones => low-throttle process

Instructor confirmed calibration was correct.

Slowly ramped throttle to 100% to verify full motor operation.

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Part 4 – Updated Wiring Diagram

Updated the team’s wiring diagram using the verified connection tables for:

Servo rail assignments

ESC connections

Power distribution

Sensor connections

Receiver => Cube => DATX mappings

(Insert wiring diagram here)

⁠

Reflection (e-Portfolio Entry)

Modifications to the DATX and Their Importance

Several critical modifications were performed on the DATX, including stick calibration, enabling Multi-Bind, selecting the correct receiver, and ensuring the output protocol was set to SBUS. These steps guarantee accurate control signal interpretation by the Cube and ensure reliable RC communication. Misconfiguration could cause incorrect control surface response or throttle issues, so correctness is essential for safe operation.

Connection of ESC and Motor in the Circuit

The ESC connects directly to the battery to provide high-current power for the motor. The servo lead from the ESC plugs into the Cube’s servo rail on the designated throttle channel (SERVO3 or SERVO4). Many ESCs also supply a regulated 5V BEC output, which powers the servos through the rail. Correct wiring ensures:

The motor receives adequate current

Servos receive safe regulated voltage

The Cube properly commands throttle

What Was Done During ESC Calibration and Why

ESC calibration synchronizes the full-range throttle signal from the transmitter/Cube with the ESC’s throttle interpretation. Without calibration, the ESC may refuse to arm, may produce incorrect RPM, or may not reach full throttle. Calibration ensures:

Zero throttle corresponds to genuine minimum output

Full throttle corresponds to maximum ESC output

Smooth and predictable throttle response

Calibration was performed in Manual Mode with the aircraft armed to allow the ESC to interpret actual PWM throttle values directly from the Cube.

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