Skip to main content
NewEpisode 8a is out: Two state machines 1: rising edgeWatch →
Robotics · Course

ServoHub From Zero

Read an open-source robot-joint servo drive line by line: the interrupts and loops, current sampling, encoders, state machines, identification and safety.

22 parts out3.4 h of video37 episodes plannedEN · 中文
Start with episode 1 (free)Jump to syllabus
What you get
  • A video for each part, with chapters
  • Slides to read at your own pace (PDF)
  • A code index with every file:line shown, linked to the source
  • Practice questions answered from real runs
Good fit
  • Motor-control engineers moving to robot joint motors
  • Embedded engineers who will work on a drive's firmware
  • Teams deciding whether to build on ServoHub
Not for
  • Learning FOC or PID from scratch: the course assumes them
  • Board wiring or PCB design
  • The inside of CANopen or EtherCAT stacks: they are treated as black boxes

Syllabus

FreeFree with accountMembersPlanned

Overview

3 parts · 16 min
1aOpening: what this course is3:451bThe Big Map 1: from power-on to the two control loops6:311cThe Big Map 2: who interrupts whom, and how the loops talk5:48
36One instruction end to end
37The big recap: what changes for a new motor

Foundations

7 parts · 69 min
2Running ServoHub on a Mac: SIL simulation8:283The whiteboard kAxis: who may write it, and through which door10:094From Simulink model to generated code12:275aBSP 1: one tick across the seam9:015bBSP 2: after the PWM switches off11:035cBSP 3: when the bus voltage falls9:395dBSP 4: asking for more than the board gives8:37

Skeleton

8 parts · 71 min
6aFour gates 1: waiting for the bus7:096bFour gates 2: interrupts on, then the encoder7:326cFour gates 3: calibrate, then open7:596dFour gates 4: one tick late6:326eFour gates 5: who interrupts whom7:297aCurrent sampling 1: when in the PWM period11:367bCurrent sampling 2: from ADC count to amps12:338aTwo state machines 1: rising edge9:54
8bTwo state machines 2: the application layer's table and five states
8cTwo state machines 3: switching both, and why the motor will not move

Current loop

Planned
9The current-loop pipeline: Clarke → Park → PI → inverse Park → SVPWM
10Current-loop details: tuning, limits, dead-time compensation

Sensors

4 parts · 50 min
11aEncoders 1: how one frame becomes an angle (Tamagawa)18:5011bEncoders 2: the other three wires (MT68xx · BiSS-C · ABZ)18:5911cEncoders 3: when the data goes bad8:2411dEncoders 4: lost ABZ pulses4:08
12Multi-turn counting, gear ratio and the load-side encoder

Control loops

Planned
13Where speed comes from: the PLL observer
14The position loop, speed loop and feedforward
15The disturbance observer
16Resonance and notch filters
17Input shaping

Identification

Planned
18Power-up alignment: direction, pole pairs, electrical zero
19Electrical and mechanical identification: R, L, J
20Torque constant, friction identification and compensation

Safety

Planned
21Protection, self-test and fault handling
22The brake
23The CiA402 state machine

Motion modes

Planned
24Trajectory planning
25PP / PV / PT and homing
26CSP / CSV / CST synchronous modes
27MIT mode: a joint that acts like a spring

Data & comms

Planned
28The parameter database and flash storage
29The product contract
30CANopen: the path of one 0x607A write
31EtherCAT: aligning the sync signal with the position loop
32The debug channel: MAVLink and the software scope

Engineering

Planned
33The Simulink project and the code-generation flow
34The Y01 board, the Keil project and the bootloader
35The factory test service