Lower-Level Controller

The embedded control board wired directly to sensors and motors, running real-time low-level control.

“Lower-level controller” (下位机) is the counterpart to “host computer” in Chinese engineering usage, referring to the compute layer wired directly to motor drivers, encoders, IMUs, and other hardware — typically an MCU (microcontroller), a DSP, or a PLC. It doesn't run large models; it only handles tasks with strict timing requirements: reading sensors and running the current loop and position loop at a high, fixed frequency, outputting PWM (pulse-width modulation) signals, and exchanging data with the host computer over CAN, EtherCAT, or a serial port, receiving targets and reporting status back. The host computer (an industrial PC, a Jetson, etc.) handles perception, planning, and policy inference. This division of labor means that if the high-level software stalls briefly, low-level control keeps running smoothly. English sources usually call this a low-level or embedded controller; “slave computer” is an older term for the same role.

ExampleOn a humanoid robot, a policy running on a Jetson might output target joint angles every 20 ms, while an STM32 lower-level controller on each joint's driver board tracks those targets in a much faster closed loop.

Also called

Slave Computer, Low-Level Controller

Related

Host Computer · Microcontroller Unit (MCU) · STMicroelectronics STM32 MCU Family · Servo Drive (Motor Driver) · Real-Time Control · Controller Area Network (CAN)

Sources

上位机 - 维基百科 (Chinese)
Microcontroller - Wikipedia