Robot basics / a buyer’s guide
A robot body, explained.
Actuators are the muscles. Sensors are the senses. But a capable body still needs the right software, power and support to do a useful job.
Chips & controllers
Run the software that interprets inputs and chooses commands. The processor can be in the robot, on a nearby computer or in the cloud.
Before buying: Which functions run locally, and which need an external computer or connection?
Sensors
Cameras, depth sensors, joint encoders and force sensors provide different kinds of feedback. Having a camera does not mean a robot understands every scene.
Before buying: Which sensors and task software are included in this exact version?
Actuators
Turn energy into movement. An electric joint may combine a motor, gearing, sensors and control electronics. Published peak strength is not the same as continuous working capacity.
Before buying: What load and duty cycle are supported for our task?
Battery
Supplies energy for a mobile robot. The useful comparison is the body’s energy reserves; a robot recharges electrically. Some arms use a mains power supply instead.
Before buying: What is the measured runtime, charging time and replacement route?
Power electronics & wiring
Power electronics regulate electrical energy. Wiring carries power and control signals. This combines two different jobs, so the body comparison is only a memory aid.
Before buying: Which charger, power supply and cables are supplied and supported?
Frame & joints
Support the machine and define how it can move. Covers, seals, feet and mounting points matter in the real workplace.
Before buying: How is it transported, mounted and checked for the intended environment?
How movement becomes a useful action
- SenseMeasure the surroundings and joints
- DecideSoftware chooses a command
- ActDrive electronics power the actuators
- Check ↺Feedback guides the next command
The battery or mains supply provides the energy. Sensor feedback closes the control loop. A useful task also needs a defined goal, suitable software and a safe working setup. A faster processor alone does not supply these.
Shared building blocks. Different robots.
Ember’s slides 9–15 connect these component families across electric technologies. That helps explain why progress in chips and batteries matters to robotics. It does not make components interchangeable, or mean a complete robot’s price will fall at the same rate.
A humanoid, quadruped and fixed arm use different combinations. Our comparison is a way to understand the jobs of the components, not a claim that robots think or learn like people. Use the exact model, revision and manufacturer’s documentation when selecting parts.
Understand the body. Check the workplace.
Next, work out where it charges, where its software runs and who helps if the task stops working.
Sources & limits
- Conceptual component comparison: Ember, The Age of Power, slides 9–15.
- Control loop explanation: Lynch & Park, Modern Robotics, section 11.1.
Checked 17 September 2026. Locations and proportions in the illustration are conceptual.