PWM Interface: Enhanced Control & Customization

Iris Dynamics Ltd. is excited to announce a new feature for ORCA Series motors: PWM (pulse-width modulation) control. The PWM Interface allows for rapid and straightforward integration for mobile robotics and remote control retrofits, with widely adopted Remote Control (RC) PWM. This approach requires no coding, minimal wiring, and integration time. With a USB Windows configuration GUI, ORCA motors ensure quick and hassle-free development and deployment of your solution.

Enabling Position Control with PWM Interface

The PWM Interface enables position control of the ORCA motor by interpreting pulse-width signals from an RC controller, such as the HX4-06222 PWM output controller. Users can configure the motor to operate between its retracted stop and a pre-configured extension length, making it ideal for various positioning applications, such as autonomous and semi-autonomous vehicles, remote control/teleoperation, embedded systems, mobile robotics, and more.

Upon boot-up, the motor performs an auto-zero function to determine the absolute position of its retracted stop. Once this initial setup is complete, the motor enters PWM input mode, where it follows the PWM signal to adjust its position accordingly. This PWM control functionality supports a frequency range from 40 Hz to 400 Hz, ensuring broad compatibility with standard controllers and meeting the needs of most common positioning applications.

Hardware Interface

An adapter is used to integrate with PWM-enabled controllers, while also providing the option to connect the motor simultaneously to IrisControls to facilitate GUI configuration over the included USB to RS485 cable.

Key Benefits for Users

Ease of Use: This feature requires no coding and minimal wiring.
Reliability: The motor enters a fail-safe error state if the PWM signal goes flat, preventing potential issues such as erratic movements or uncontrolled positions.
Low Voltage: ORCA motors accept 12V to 60V DC, making them ideal for operation from batteries or directly from a vehicle’s electrical system. With low-cost, off-the-shelf RC equipment, PWM control enables rapid and easy integration.
Customization: The motor’s behavior, including position, soft start, and response to error states, can be finely tuned through GUI configuration settings.
Flexibility: The system works independently of Iris Controls but can still be connected for saving live (persistent) configurations and for live monitoring, as needed.
Smooth Operation: The motor includes built-in configurable features such as soft start and filtering to ensure smooth transitions and minimize unwanted vibrations and noise, particularly in high-stress or sensitive environments.

How the PWM Interface Works

With a small amount of configuration, the following sequence can automatically occur on power-up:

1. Auto-Zero Function (0 to 8 seconds): The motor performs an auto-zero routine to determine the retracted stop position
2. Transition to PWM Mode (3 seconds): The motor smoothly transitions to PWM input mode, beginning to follow the PWM signal commands.
3. Position Control (onward): The motor follows the PWM signal to adjust its position between the minimum and maximum positions.

By default, the motor interprets a range of pulse widths from 1 ms (fully retracted at the minimum position) to 2 ms (fully extended at the maximum position), with a center position at 1.5 ms. Configurable parameters like the position controller soft-start time and PWM signal filtering allow users to fine-tune the system for their specific needs.

Configuring the PWM Interface

Users can easily configure and save settings to the motor using IrisControls. Key configuration options include:

• PWM Timeout: The time before the motor enters error mode due to a flat PWM signal.
• PWM Filtering Time Constant: Controls the amount of filtering applied to incoming PWM signals.
• Minimum Motor Extension Setting: Defines the minimum position of the motor.
• Maximum Motor Extension Setting:  Defines the maximum position of the motor.
• Servo Control Type: Select from 180-degree servo control (1-millisecond to 2-millisecond pulses) and 270-degree servo control (0.5-millisecond to 2.5-millisecond pulses).
• Soft-Start Time: Configures the ramp-up time for the position controller to avoid sharp transitions.
• Auto-Zero Parameters: These settings define the force and speed of the auto-zero routine, ensuring accurate position discovery.

Significance

The need for adaptability in control systems is ever-growing, and with the new PWM Interface, users can now directly control the position of ORCA Series motors using standard RC controllers. This new feature is specifically designed to enhance the motor’s versatility, particularly for applications where PWM control is preferred due to existing system compatibility, reduced complexity, or cost considerations.

By introducing this custom solution, we empower users to easily implement ORCA Series motors into their systems without needing to rely on IrisControls for every instance of operation. However, connection to IrisControls remains an option for detailed configuration and fine-tuning.