Piper Arm Controller

A simple and interactive Python interface for controlling the Piper robotic arm via the piper_control API. Build on the work of Reimagine Robotics.

This controller allows you to:

• Set joint positions absolutely or relatively
• Open/close the gripper with precise control
• Interact with the robot from the terminal using simple text commands

🚀 Installation

1. Install CAN utilities (required for communicating with the Piper arm)

sudo apt install can-utils

2. Install the piper_control Python package

pip install piper_control

🧠 Overview

This controller script provides the following functionality:

• Move the arm to a start position
• Move joints by providing absolute or relative values (radians or degrees)
• Open or close the gripper
• Run an interactive terminal interface for manual control

🧩 Features

• Absolute and relative joint control
• Degrees and radians support
• Interactive gripper control (open, close, or partial)
• Current state feedback after every command

🛠 Usage

Run the controller

python3 driver.py

🎮 Interactive Terminal Commands

When running, you’ll be able to enter:

Joint control:

• Absolute radians:

  1.0 -0.5 0.3 0.2 -1.2 0.8
  

• Absolute degrees:

  45 -30 15 10 -70 45d
  

• Relative radians:

  +0.1 0 -0.2 0 0.3 0
  

• Relative degrees:

  +5 0 -10 0 15 0d
  

Use the prefix + to indicate a relative movement and suffix d to enter values in degrees.

Gripper control:

Type g and press enter to enter gripper mode:

• o: Open gripper fully
• c: Close gripper fully
• 0.0–1.0: Set gripper position (0 = closed, 1 = open)
• b: Go back to joint control

Quit:

Type q or quit or exit at any time to leave the controller.

📍 Default Start Position

This is the default joint configuration in radians:

[-1.593, 0.634, -0.286, 0, 0.385, -1.85]

Use arm.set_start_position() in code to return to this pose.

🧪 Programmatic Example

Here’s how to use the controller from your own script:

from piper_arm_controller import PiperArmController
import numpy as np

arm = PiperArmController()
arm.set_start_position()

# Move arm relative to start
arm.set_relative_angles(np.array([0.1, 0, -0.2, 0, 0.1, 0]))

# Open gripper halfway
arm.set_gripper(0.5)

📦 Dependencies

• piper_control (Python package)
• can-utils (Linux CAN communication utilities)
• Python 3.7+

👨‍🔧 Troubleshooting

• Make sure the CAN device is available (e.g., can0)
• Ensure Piper is connected and powered on
• Run with sudo if permissions are restricted on can0