What Is a Robot Controller?

A robot controller is the computer at the centre of a robot. It takes in sensor data, decides what the robot should do next and sends commands to the motors, many times a second. Everything from a six-axis welding arm to a warehouse robot has one, although what it looks like varies a great deal.

The work splits into layers. At the bottom, servo loops hold each motor at the commanded position and speed, often thousands of times a second. Above that, motion planning works out the path each joint or wheel must follow. At the top sits task logic: which part to pick, which aisle to drive down, what to do if a person steps into the way. Safety functions run alongside all three and can stop the robot whatever the other layers are doing.

On a simple machine one controller runs every layer. On a modern mobile or vision-guided robot the layers are often spread across several devices: motor drives for the servo loops, a safety controller for the stops, and a computer for perception and planning.

Where those layers run depends on the kind of robot.

In many modern cells these are not alternatives but partners. The arm controller moves the arm, the PLC runs the line and an edge AI computer tells both what the cameras see.

An edge AI robotics controller needs more than processing power. NVIDIA Jetson modules are widely used because they combine GPU AI performance with low power, and the module sets the ceiling: a Jetson Orin Nano suits a small robot running one or two camera models, while Jetson AGX Orin and Jetson Thor handle many cameras, larger models and sensor fusion on the same computer. Our guide to choosing a Jetson module compares them. The computer built around the module then decides how well it suits a robot.

Industrial robot safety is set by ISO 10218, with functional safety requirements from standards such as ISO 13849 and IEC 62061. In practice, safety functions such as emergency stop, protective stop and speed limiting run on certified safety hardware: the arm controller’s safety board, a safety PLC or safety-rated laser scanners. An AI computer can add perception, for example spotting a person near a cell, but it normally supplements the certified safety chain rather than replacing it. Our cobot safety standards FAQ covers how those standards fit together.

Our rugged Jetson computers include robotics controllers built on Jetson Orin and Jetson Thor, with up to 16 GMSL camera inputs, isolated CAN FD, PoE and 10GbE depending on the model. The human-robot collaboration case study shows Vecow robotics controllers in use.

We supply Jetson robotics controllers with the module, storage, JetPack image and camera drivers fitted as standard, and validate the camera and CAN interfaces before the system ships.