Motivation or what's wrong with cheap ESCs

Are you building a small UAV? Then you have definitely faced the problem of choosing electronic modules that are reliable while having a rich enough feature set. We are also building our own UAV, and we were unable to find suitable power regulator and motor controller (ESC). Generic parts for RC models are not really suitable for UAVs. There are a few reasons for that:

• The reliability, efficiency and accuracy does not meet requirements to autonomous flight;
• They don't offer a suitable micro-controller interface, such as SPI or I2C;
• No feedback channel to acquire life-critical flight information. You cannot read out such things as the current and battery voltages, motor real RPMs etc. You can't even check if the motor is running at all;
• No doubling of critical circuits such as the power rail.

That is why we have designed our own controller from scratch using only high-quality latest components.

auSpeed-1M Combo Controller

The auSpeed-1M Combo Controller is an integrated module that combines three sub-systems for a UAV:

• High efficient protected power supply for electronic units and servos with power doubling and voltage/current sensors (BEC);
• Brushless motor speed controller (ESC), up to 40A;
• Six channel servo controller with a standard PWM output.

Features

The integration of the three functional units allows to simplify interfacing the subsystems by one physical bus i2c with a common protocol and to improve the efficiency and reliability of the systems by eliminating extra connectors for high current wires and data interfaces.

• The board features doubling of the input supply sources, allowing using an auxiliary battery as a backup of the main source with additional function of deep surge protection.
• The use of high-end specialized chips and powerful processors allows high efficiency in power conversion and motor control circuits.
• The board provides real-time operational feedback, monitoring the actual motor rotations per minute, current consumption, batteries’ voltage etc.

Fig.1. Block Diagram

Specifications

Power Supplies

• Power Rail 1: +3.3V±1.5%
• Power Rail 2: +5.1V±1.5%
• Max output current: 4A, 4A
• Output ripple: (@2A) 20mVp.p.
• Efficiency up to 94%
• Switching frequency: up to 1200kHz
• Overcurrent protection: yes

Motor Control

• Motor type: BLDC
• Motor Current: 0..40A
• Number of channels: 1

Servo control

• Number of channels: 6
• PWM frequency: 100Hz
• Servo type: standard digital/analog

General

• Main battery voltage: 11.1-18.5V (3S-5S Li-Po)
• Auxiliary battery voltage: 7.4V (2S Li-Po)
• Interface: i2c
• Command frequency: up to 200 per sec
• Operational temperature: -40..+85°C
• Dimensions: 65 x 40 x 20 mm
• Weight with connectors < 48 g
• Presumption of lifetime 5,000 hours