High Level Command — Python Example

Source: rbq_sdk/python/example/sport/rbq_high_level.py

Python port of rbq_high_level.cpp.
Publishes HighLevelCommand at 50 Hz over DDS, selects gaits from the terminal, and reads joystick velocity setpoints.

Overview

Three concurrent actors:

Actor	Rate	Role
Control loop thread	50 Hz	Publishes `HighLevelCommand` with current gait + velocity
Joystick loop thread	100 Hz	Polls joystick and updates velocity setpoints
Main thread (terminal)	blocking	Reads gait names / IDs from stdin

At startup the control loop publishes switchControlMode = true once (after 200 ms), enabling EXT_JOY mode on the robot stack. Without this, HighLevelCommand is ignored.

Prerequisites

rbq_sdk_py installed — see Python SDK Overview.
A Linux joystick device at /dev/input/js* (required to start).
Robot stack running (simulation or hardware).

Install & Run

bash

cd RBQ/rbq_sdk/python
pip install -e .

bash

cd RBQ/rbq_sdk/python/example/high_level
python3 rbq_high_level.py <networkInterface> [joystickPath]
# e.g.
python3 rbq_high_level.py eth0
python3 rbq_high_level.py eth0 /dev/input/js1

Joystick auto-detection: prefers a device whose name contains "Logitech", "gamepad", "Xbox", or "wireless", then falls back to the first available js* node.
Override via argument or JOY=/dev/input/js1 python3 rbq_high_level.py eth0.

Terminal commands

list              # print all available gaits
standing          # switch to STANDING by name
3                 # switch to TROTTING by ID
rl_trot           # switch to RL_TROT by name

Available gaits

Name	ID	Description
`sitting`	0	Robot sits on the ground
`standing`	1	Neutral standing posture (default at startup)
`aiming`	2	Aiming posture
`trotting`	3	MPC trot gait
`trot_stairs`	4	Stair-adaptive trot
`waving`	5	Slow walk gait
`trot_running`	6	High-speed trot
`docking`	10	Auto-docking sequence
`rl_trot`	30	RL-based trot
`rl_front_walk`	31	RL forward walk
`rl_left_walk`	33	RL lateral left walk
`rl_right_walk`	34	RL lateral right walk
`rl_bound`	35	RL bound gait
`rl_pace`	36	RL pace gait
`rl_pronk`	37	RL pronk gait
`rl_3leg_hr`	38	RL 3-leg (hind-right lifted)
`rl_3leg_hl`	39	RL 3-leg (hind-left lifted)
`rl_3leg_fl`	41	RL 3-leg (front-left lifted)
`rl_trot_vision`	42	RL trot with vision
`rl_trot_run`	45	RL trot run
`rl_silent`	46	RL silent gait
`rl_stairs`	47	RL stair climbing
`rl_walk_vision`	48	RL walk w/ terrain height feedback (height/pitch adjustable)
`rl_walk`	49	RL walk (height/pitch adjustable)
`rl_end`	80	RL end state

Joystick velocity controls

Axis	Maps to	Max value
Left stick Y (forward)	`vel_x`	±1.2 m/s
Left stick X (lateral)	`vel_y`	±0.5 m/s
Right stick X (yaw)	`omega_z`	±60 deg/s

Deadzone of 0.12 applied before scaling.

omega_z units: sent in deg/s — QuadWalk multiplies by D2R internally.

DDS topics

Direction	Topic	Message type
Publish	`rt/rbq/cmd/highLevel`	`HighLevelCommand_`
Publish	`rt/rbq/cmd/switchControlMode`	`Bool_`

Key implementation notes

gait_transition flag: A threading.Lock-protected consume_gait_pending() method ensures the flag is consumed exactly once per gait change — mirrors the C++ std::atomic::exchange() pattern.
switchControlMode: Published once at startup after a 200 ms delay. If not published, the robot ignores HighLevelCommand.
Timing: The control loop uses time.monotonic() and time.sleep() for 20 ms pacing. On slip, it resets next_tick to avoid clock drift.
No RT thread: Unlike the C++ version, no real-time thread is used. sudo is not required.

High Level Command — Python Example ​

Overview ​

Prerequisites ​

Install & Run ​

Terminal commands ​

Available gaits ​

Joystick velocity controls ​

DDS topics ​

Key implementation notes ​

See also ​