By the end of this lesson you will be able to
- say what a humanoid robot is, and what is inside one in general terms
- explain why robots need maintenance, and tell corrective, preventive and condition-based maintenance apart
- describe the five steps of a maintenance job: look, find, make safe, fix, prove and record
- know what this course teaches, what it does not, and how the lessons work
A machine built for human spaces
A humanoid robot is a machine with a body plan like ours: a head, a torso, two arms with hands, and two legs. People build them for one main reason. Almost everything we have made, from doorways and stairs to tools, counters and lifts, was made to suit a human body. A robot with a human shape can, in principle, work in those places without the places being rebuilt for it.
That is a demanding job for a machine. To stand, walk, turn its head and hold something, a humanoid robot has to move many joints at once and keep its balance while it does so. It also has to work near people. Both facts explain why looking after such a robot is a skilled trade, and why this course begins with careful habits before it touches anything.
This course teaches the diagnostic thinking, the safety habits and the record-keeping that good robot maintenance depends on. It does not replace the maker's service manual, and it does not qualify anyone to work on a real robot. Real work needs the training and the manual for the robot in front of you. The robot in this course, Bramble, is fictional, and every number you see in the practice console is teaching data.
What is inside a humanoid robot
Different makers build their robots differently, but most humanoid robots share the same main parts:
| Part | What it does | Everyday picture |
|---|---|---|
| Frame | The structure that holds everything together and carries the weight | The skeleton |
| Actuators | Motors, usually electric, with gearboxes, that move each joint | The muscles |
| Sensors | Measure joint angles, tilt, the force under the feet, sound and pictures | The senses and the inner ear |
| Controller | The robot's computer, which reads the sensors and tells the actuators what to do | The brain |
| Battery | Stores the electrical energy the whole robot runs on | The heart and the food |
| Software | The programs, called firmware when they live inside the machine, that make it all work together | Habits and skills |
Every one of these parts can go wrong. Moving parts wear. Lubricant runs low. Motors and batteries get hot. Sensors slowly drift away from the truth. Cables work loose as a robot walks. Software is updated, and sometimes an update causes a fresh problem. A fault in a machine that is walking near people is more than an inconvenience, so it must be found early and fixed safely.
Meet Bramble
Throughout this course you will look after one robot. Bramble (model HR-7) is a demonstration humanoid with 17 joints. It works as a guide in a small museum, where the curator, Alice Bennett, is very fond of it, and its daily operator, Oliver Grant, notices when it does not seem quite right.
You will play Eleanor Price, a new technician at the Ashdown Robotics Workshop. Your mentor is the senior technician Henry Wren, and the workshop manager is Margaret Ellis. Every lesson from Lesson 1.2 opens with a short job card, a work order from one of them, and then teaches you what you need to do the job.
Here is your first look at Bramble through the workshop's service console, the program a technician uses to talk to the robot. The command status asks for a summary. It is only a picture for now; in Lesson 1.2 you will type commands yourself.
$ status Unit Bramble (HR-7, serial HR7-0412) Time 2025-11-03 10:30:00 Power on Mode live (drives enabled) Position standing on the floor Battery 78 % (discharging) Hottest joint left-knee, 43.7 C Active faults 0 Firmware 2.4.0 Uptime 2 h 32 min Service 388 h since last service (interval 500 h)
Read it as you would read a car's dashboard. Bramble is on, working normally, the battery is at 78 per cent, the hottest joint is the left knee at a comfortable temperature, and there are no faults. Most of your work will be to notice when a picture like this stops looking normal, and to work out why.
Three kinds of maintenance
Maintenance work falls into three kinds, and a good workshop uses all of them:
| Kind | When it happens | Example with Bramble |
|---|---|---|
| Corrective | After something has gone wrong | The left knee shuts down from heat, so you find out why and repair it |
| Preventive | On a schedule, before anything has gone wrong | Every 500 hours you inspect, clean, lubricate and check every joint |
| Condition-based | When the robot's own readings show trouble is coming | You notice a joint's temperature creeping up week by week and act before it fails |
This course is mostly about diagnosis: finding out what is wrong, and why, before you change anything. Diagnosis is the skill that makes all three kinds of work cheaper and safer. A technician who replaces parts on a guess wastes money and can miss the real fault. A technician who reads the evidence first usually fixes the right thing once.
The job in five steps
Every maintenance job in this course follows the same five steps. You will meet each one again and practise it many times.
| Step | What you do | Where the course teaches it |
|---|---|---|
| 1. Look | Listen to what the operator noticed, then read the robot's status and faults | Modules 2 and 3 |
| 2. Find | Read the log and the trends, compare with the robot's other side, and work out the likely cause | Modules 3 and 5 |
| 3. Make safe | Put the robot in its safe state before touching it | Module 4 |
| 4. Fix | Change one thing at a time, starting with the cheapest and simplest | Modules 5 and 6 |
| 5. Prove and record | Test that the fault is gone, watch that it stays gone, and write down what you did | Modules 6 to 8 |
Notice that making the robot safe comes before fixing, not after. A humanoid robot can move, fall or be live with stored energy even when it looks still. Module 4 is short, but it is the module that every other module depends on.
What you will learn
The course has nine modules and 33 lessons.
| Module | What you will be able to do |
|---|---|
| 1. Getting Started | Know the parts of a humanoid robot and use the service console |
| 2. Reading the Robot | Read the status, every joint, every sensor and the battery, and know what is normal |
| 3. Logs and Fault Codes | Read the event log, filter it, look up fault codes and read trends |
| 4. Safety First | Recognise the hazards and put a robot in its safe state correctly |
| 5. The Fault-Finding Method | Find the cause of overheating, bus, balance and vibration faults, and fix them without wasting parts |
| 6. Testing and Calibration | Run self-tests, calibrate joints and sensors, and prove that a repair worked |
| 7. Batteries in Practice | Charge safely, judge battery health and respond to battery faults |
| 8. Preventive Maintenance | Inspect, lubricate, clean, update firmware safely, and keep proper records |
| 9. Putting It All Together | Carry out a full service of Bramble from start to finish |
How the lessons work
Learning maintenance from reading alone does not work, because it is a skill of the hands and of the eye. So every lesson from 1.2 onwards has live service consoles. Each one is a small simulation of Bramble that runs in your browser. It has joints that heat up, sensors that drift, a battery that drains and an event log that fills, and it follows the safety rules a real workshop would, so you can practise finding and fixing faults without any risk.
Beside each console you will see a picture of the robot. Each joint is a coloured dot: green for fine, amber for a warning, red for a fault. Watching the colours change as you work is the fastest way to see what your commands are doing.
Each lesson has the same shape: a short lesson with examples you can try, five exercises that check your work automatically, and a four-question quiz. Nothing you do can harm a real machine, so experiment freely, and press Reset to start again whenever you like.
Only a web browser. You do not need any robot, tool or program, and you do not need to know anything about electronics. If you can read a table and follow a careful procedure, you can do this course.
Quick check
Four questions to confirm the main ideas. Choose an answer to see the explanation.
Which list names the main parts found inside most humanoid robots?
Most humanoid robots share a frame, actuators (motors and gearboxes) at the joints, sensors, a controller computer, a battery and software. The other lists describe other machines.
Oliver reports that Bramble's left knee shut down from heat this morning. What kind of maintenance job is this?
Work done after a fault has happened is corrective. Preventive work happens on a schedule before faults, and condition-based work acts on early warning signs.
Why does the course put "make safe" before "fix"?
A humanoid robot can move unexpectedly and can store energy, so the safe state comes first. It is a habit that protects you, not a rule about whether a repair is possible.
A technician replaces a joint's motor because "it is probably the motor", without reading the log or the readings. What is the main risk?
Replacing parts on a guess wastes money and can leave the real fault in place. Diagnosis means reading the evidence first.
Summary
- A humanoid robot has a head, torso, arms, hands and legs, so that it can work in spaces built for people.
- Most humanoid robots have a frame, actuators, sensors, a controller, a battery and firmware. Every part can wear, drift, heat up or fail.
- Corrective maintenance fixes a fault, preventive maintenance follows a schedule, and condition-based maintenance acts on early warning signs.
- Every job follows five steps: look, find, make safe, fix, prove and record.
- This course teaches diagnostic thinking, safe habits and record-keeping. It does not replace the maker's manual or training.
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