olive® Servo ​

Overview ​

The olive® Servo the easiest way to get your own robotic system moving! This high-performance robotics component is designed for use in a wide range of applications. It is re-programmable and easy to integrate, making it simple for users to build their own custom robots and automated systems. The actuator has a plug and play design, making it quick and easy to install and set up, and it is compatible with multiple robotic operating systems, giving users flexibility in terms of the software tools they can use.

Key Features ​

• ROS and ROS2 out of the box. No setup required.

• High-torque motor: The olive® Servo module features a high-torque motor that provides the power and torque needed to move heavy loads or to perform high-precision tasks.

• Easy integration: The olive® Servo is designed to be easy to integrate into a variety of different robotic systems. It just works through plug and play.

• Daisy-chainable: Extend your system's funcionality by plugging additional hardware into the olive® Servo's input port: be it any other olive® hardware component or another USB-C peripheral.

• Various control modes: olive® Servo offers four different modes of control: raw control (pwm), position control, velocity control, and torque control.

• Software-defined: The olive® Servo is software-defined, allowing users to customize its communication layer, behaviour, and functionality through software rather than hardware.

• Auto-voltage: the olive® Servo can run in different voltage modes: 5 / 9 / 12V. The specific voltage is automatically adjusted to the power intake to ensure maximum performance in all conditions.

olive® Servo Models ​

The olive series of servos includes four different models that are distinguished by their rotations per minute (RPM). Each servo comes with with an on-board 9D high-performance IMU. These are the available options:

Olive® Operational Modes ​

To change the servo mode you can open the debug gui and select the servo's mode:

1. PWM Control ​

Description: Pulse Width Modulation (PWM) control is a technique used to regulate the power supplied to electrical devices, such as actuators. It adjusts the duty cycle of the input signal, controlling the amount of power provided to the actuator.

• Input: Duty cycle (-1 to 1)
• Output: Power supplied to the actuator
• Subscriber topic: /olive/actuator/name_space/pwm

2. Position Control ​

Description: Position control is used to maintain or adjust the position of an actuator. The controller computes the difference between the desired and actual positions and adjusts the actuator accordingly.

• Input: Desired position
• Output: Actual position of the actuator
• Subscriber topic: /olive/actuator/name_space/goal/position
• PID: A PID controller is used to minimize the position error, adjusting the control signal to change the actuator's position.

3. Velocity Control ​

Description: Velocity control is used to maintain or adjust the velocity of an actuator. The controller computes the difference between the desired and actual velocities and adjusts the actuator accordingly.

• Input: Desired velocity
• Output: Actual velocity of the actuator
• Subscriber topic: /olive/actuator/name_space/goal/velocity
• PID: A PID controller is used to minimize the velocity error, adjusting the control signal to change the actuator's velocity.

Technical Specifications ​

Quick Setup ​

1. Follow the Quick Start Guide for Olive Robotics robot modules to connect the device and start using it.

2. When the servo is correctly connected to your system, you can check that the expected ros topics are present. On your host PC run:

   ros2 topic list

   ros2 topic list

   The following ROS topics showed be shown:

   /olive/servo/x1681709875/pwm
   /olive/servo/x1681709875/magnet/angle
   /olive/servo/x1681709875/magnet/moving_average
   /olive/servo/x1681709875/magnet/auto_gain
   /olive/servo/x1681709875/magnet/magnitude
   /olive/servo/x1681709875/magnet/diagnostic
   /olive/servo/x1681709875/joint
   /olive/servo/x1681709875/joint/voltage
   /parameter_events
   /rosout

   /olive/servo/x1681709875/pwm
   /olive/servo/x1681709875/magnet/angle
   /olive/servo/x1681709875/magnet/moving_average
   /olive/servo/x1681709875/magnet/auto_gain
   /olive/servo/x1681709875/magnet/magnitude
   /olive/servo/x1681709875/magnet/diagnostic
   /olive/servo/x1681709875/joint
   /olive/servo/x1681709875/joint/voltage
   /parameter_events
   /rosout

3. Control the servo and visualize the data using one of the available options.

4. Change the parameters like IP, ROS topic name, etc. using the embedded web interface. You just need to open your browser on your host computer and enter the IP address of the device. If you didn't change the default IP address, then it must be 10.42.0.7.

ROS Topics and Services ​

PWM Control Mode (Base topics) ​

Position Control Mode (Additional topics) ​

Velocity Control Mode (Additional topics) ​

Advanced Settings ​

The device allows certain parameters to be changed at runtime. To get an overview of all changeable parameters use ros2 param list. To change a parameter use ros2 param set /dcm_actuator <parameter> <new_value>

Servo ​

PWM Control Mode (Base params) ​

Position Control Mode (Additional params) ​

Velocity Control Mode (Additional params) ​

System ​

Mechanical Details ​