dora/examples/mujoco-sim/gamepad_control

• 03. Gamepad Control
• • Controller Types
  • • 1. Basic Gamepad Control (gamepad_control_basic.yml)
    • 2. Advanced Gamepad Control (gamepad_control_advanced.yml)
  • Gamepad Controls
  • Running the Examples
  • • Basic Gamepad Control
    • Advanced Gamepad Control
    • Gamepad Node (gamepad)
    • Gamepad Controller Scripts
  • Gamepad Mapping
  • Key Features
  • Troubleshooting

03. Gamepad Control

This example demonstrates real-time interactive control by connecting a gamepad to the controller. It builds upon the target pose control example by adding gamepad input processing for teleoperation of the robot arm.

Controller Types

1. Basic Gamepad Control (gamepad_control_basic.yml)

• Direct IK approach: Uses simple IK solver for immediate position updates
• The movement fells jumpy

2. Advanced Gamepad Control (gamepad_control_advanced.yml)

• Differential IK approach: Smooth velocity-based control with Jacobian
• Smooth: Continuous motion interpolation
• Use case: Precise manipulation, smooth trajectories

Gamepad Controls

• D-pad Vertical: Move along X-axis (forward/backward)
• D-pad Horizontal: Move along Y-axis (left/right)
• Right Stick Y: Move along Z-axis (up/down)
• LB/RB: Decrease/Increase movement speed (0.1-1.0x scale)
• START: Reset to home position [0.4, 0.0, 0.3]

Running the Examples

1. Connect a gamepad (Xbox/PlayStation controller via USB or Bluetooth)

Basic Gamepad Control

cd gamepad_control
dora build gamepad_control_basic.yml
dora run gamepad_control_basic.yml

Advanced Gamepad Control

cd gamepad_control
dora build gamepad_control_advanced.yml
dora run gamepad_control_advanced.yml

You should see:

1. Robot responds to gamepad input in real-time
2. Basic: Immediate position jumps based on gamepad input
3. Advanced: Smooth incremental movement with velocity control
4. Speed scaling with bumper buttons
5. Reset functionality with START button

Gamepad Node (gamepad)

Built-in Dora node that interfaces with system gamepad drivers using Pygame.

- id: gamepad
  build: pip install -e ../../../node-hub/gamepad
  path: gamepad
  outputs:
    - cmd_vel     # 6DOF velocity commands
    - raw_control # Raw button/stick states
  inputs:
    tick: dora/timer/millis/10  # 100Hz polling

• cmd_vel: 6DOF velocity array [linear_x, linear_y, linear_z, angular_x, angular_y, angular_z]

  • Generated from D-pad and analog stick positions
  • Continuous updates while controls are held

• raw_control: JSON format gamepad state

Gamepad Controller Scripts

Basic Controller (gamepad_controller_ik.py):

Gamepad Input → Target Position Update → IK Request → Joint Commands

• Updates target position incrementally based on gamepad
• Immediate position jumps

Advanced Controller (gamepad_controller_differential_ik.py):

Gamepad Input → Target Position → Pose Error → Velocity → Joint Commands

• Continuous pose error calculation and velocity control
• Smooth interpolation between current and target poses
• Real-time Jacobian-based control

Gamepad Mapping

The controller expects standard gamepad layout: (The mapping may change based on controller)

Control	Function
D-pad Up/Down	X-axis movement
D-pad Left/Right	Y-axis movement
Right Stick Y	Z-axis movement
Left Bumper	Decrease speed
Right Bumper	Increase speed
START button	Reset position

Key Features

Real-time Teleoperation:

• Incremental position updates based on continuous input
• Immediate feedback through robot motion

Speed Control:

• Dynamic speed scaling (0.1x to 1.0x)
• Allows both coarse and fine manipulation

Features:

• Home position reset capability
• Bounded movement through incremental updates
• Working on collision avoidance

Troubleshooting

"Gamepad not responding"

# Check if gamepad is connected
ls /dev/input/js*
# Test gamepad input  
jstest /dev/input/js0
# Grant permissions
sudo chmod 666 /dev/input/js0

"Robot doesn't move with D-pad"

• Check cmd_vel output: should show non-zero values when D-pad pressed
• Verify correct gamepad mapping for your controller model

"Movement too fast/slow"

• Use LB/RB buttons to adjust speed scale
• Modify delta = cmd_vel[:3] * 0.03 scaling factor in code if required