Background

• Supported TMC boards: TMCM-1461-CoE
• Supported communication interface and interface driver: CANopen-over-etherCAT (SOEM)
• Supported ROS and OS distro: Noetic (Ubuntu 20.04)
• Supported platform: Intel x86 64-bit (amd64)
• Supported setup: Single/Multiple TMC in Single ECAT interface (namespace-managed)

:memo: Note: Although officially supported TMC boards are only the abovementioned, all market-ready TMCs with YAMLs in this repository are also expected to work and can be tried and tested by the users. Contact the Developers for any issues encountered.

Hardware

For the tested TMCM-1461-CoE setup, the following are used:

• 1 x TMCM-1461-CoE
• 1 x External 24V power supply
• 1 x USB to LAN ethernet adapter

Also the following:

• 1 x 4pin female M8-RJ45 etherCAT cable
• 1 x 4 pin male M8 power supply cable

The image below shows the connection diagram of the setup (with labels):

The image below shows the actual setup used (for reference):

Software

Software Architecture

Software Dependencies

Assumptions before building this package:

• Installed ROS Noetic. If not, follow these steps.
• Setup catkin workspace (with workspace folder named as “catkin_ws”). If not, follow these steps.

Packages installed on rosdep (See Build)

• ros-noetic-ethercat-grant - accessing network interface, including Ethernet interfaces, often requires root privilege for security reasons. ethercat_grant allows the node to run without root privilege.
• ros-noetic-soem - an EtherCAT master library.

Clone

In the website:

1. Make sure that the branch dropdown is set to “noetic”.
2. Click the “Clone” or “Code” button, then copy the SSH or HTTPS link (eg, “*.git”).

In a terminal, do the following:

$ cd ~/catkin_ws/src
$ git clone <copied SSH o HTTPS link here> adi_tmc_coe #clones repo to "adi_tmc_coe" directory name

Note: If you have previously cloned and built v1.0.0 of this package, additionally do the following for clean-up:

$ cd ~/catkin_ws/src/adi_tmc_coe
$ git pull
$ rm -rf dependencies/ #removes dependencies/ directory as soem will be installed through rosdep install in newer versions

Build

Do proper exports first:

$ source /opt/ros/<ROS version>/setup.bash

Where:

• “ROS version” is the user’s actual ROS version

Then, install all required dependencies (See SoftwareDependencies) using rosdep:

$ rosdep init
$ rosdep update
$ rosdep install --from-paths src -y --ignore-src

Then:

$ cd ~/catkin_ws/
$ catkin_make clean
$ catkin_make
$ source devel/setup.bash

Pre-Launch (One-time per setup)

Not all Trinamic modules are on TMCL_IDE specially CoE due to different interface used. Check module first for other communication protocol than CoE (UART, USB or CAN). Proceed to next steps if module is available in TMCL_IDE.

:memo: Note: Different communication protocol might need different cable to communicate with TMCL_IDE (e.g. UART - USB to TTL adapter, USB - TypeC/TypeB/Micro, CAN - PCAN-USB adapter).

If it’s the first time to use the set of motors for the TMC, it is required to calibrate and tune the PID settings of the motors first.

Do the calibrations/tuning by downloading and using TMCL-IDE.

BLDC Motors

Calibrate the motors

For a run-through/tutorial of how the calibration is done in the TMCL-IDE via its Wizard Pool feature, check this link.

Tune the PI settings of the motors

For a run-through/tutorial of how the PI tuning is done in the TMCL-IDE via its PI Tuning feature, check this link.

:memo: Note: For all the calibration and tuning done, store all the parameters set from TMCL_IDE on the board’s EEPROM. Do this by doing any of the following:

• Clicking the “Store Parameter” under Settings of each axis
• Using STAP (Store Axis Parameters) command from Direct Mode
• Creating and uploading a TMCL Program, and enabling the “auto start mode” under SGP (Set Global Parameter) command from Direct Mode
• • :memo: Note: Some boards don’t have “auto start mode”, so in such a case, use the other options to store the parameters.

Stepper Motors

Calibrate the motors

For a run-through/tutorial of how the calibration is done in the TMCL-IDE via its Wizard Pool feature, check this link.

For more information about Trinamic features on stepper motors, visit this link.

:memo: Note: For all the calibration and tuning done, store all the parameters set from TMCL_IDE on the board’s EEPROM. Do this by:

• Creating and uploading a TMCL Program, and enabling the “auto start mode” under SGP (Set Global Parameter) command from Direct Mode

Config/Launch File

Before launching the package, make sure that the interface_name on the yaml file is correct. Modify the corresponding yaml file depending on your setup:

• If using 1 slave with 1 axis, modify 1slave_1axis.yaml,
• If using 2 slaves with 1 axis per slave, modify 2slaves_1axis_per_slave.yaml,
• If using 2 slaves with 2 axes per slave, modify 2slaves_2axes_per_slave.yaml,

Modify interface_name (check Parameter) and set the interface name of your adapter.

To check the interface name, run this command in terminal:

$ ifconfig

Interface name is usually starts with enx / eth. Copy and paste the interface name on the interface_name in yaml file.

Also, check the launch file if correct trinamic board autogenerated yaml and config yaml is loaded. TMCM-1461 setup is the default namespace for 1slave_1axis and 2slaves_1axis_per_slave launch files, provide the correct namespace if other device is used.

Launch

This package has 3 sample launch files for:

single slave with single axis (used module is TMCM-1461-CoE)

$ roslaunch adi_tmc_coe 1slave_1axis.launch

2 slaves with single axis on both slaves (used module is 2x TMCM-1461-CoE)

$ roslaunch adi_tmc_coe 2slaves_1axis_per_slave.launch

2 slaves with 2 axes on both slaves

$ roslaunch adi_tmc_coe 2slaves_2axes_per_slave.launch

Nodes

tmc_coe_ros_node

:memo: _Note: For those with and in the topic names, these are the slave number and motor number respectively. For example, if there are 2 slaves/devices both with single motor used, there should be two published topics for tmc_coe_info, specifically /tmc_coe_info_1_0 for device 1 motor 0 and /tmc_coe_info_2_0 for device 2 motor 0._

Published topics

These are the default topic names, topic names can be modified as a ROS parameter.

• **/tmc_coe_info__ (adi_tmc_coe/TmcCoeInfo)**
  • Data containing:
    • (1) interface name
    • (2) slave number
    • (3) motor number
    • (4) mode of operation
    • (4) status word
    • (5) velocity (if Parameter wheel_diameter is set to 0, the unit for published velocity is rpm, else m/s)
    • (6) position (if Position Scaler and Encoder steps are not available as device parameter, the unit for published position is steps, else degree angle)
    • (7) torque (mA)

Subscribed topics

• **/cmd_vel__** (geometry_msgs/Twist)
  • Velocity command (rpm or m/s)
• **/cmd_abspos__** (std_msgs/Int32)
  • Absolute position command (steps or degree angle)
• **/cmd_relpos__** (std_msgs/Int32)
  • Relative position command (steps or degree angle)

Advertised services

• /read_SDO (adi_tmc_coe/read_write_SDO)
  • Executes a read command using SDO protocol
  • The output contains raw data (velocity = rpm, position = steps) from the board. Do not expect same unit from the publisher.

• /write_SDO (adi_tmc_coe/read_write_SDO)
  • Executes a write command using SDO protocol
  • The input value should be the default unit (velocity = rpm, position = steps) from the board. Do not expect same unit from the publisher.

• /read_PDO (adi_tmc_coe/read_write_PDO)
  • Executes a read command using PDO protocol.
  • The output contains raw data (velocity = rpm, position = steps) from the board. Do not expect same unit from the publisher.

• /write_PDO (adi_tmc_coe/read_write_PDO)
  • Executes a write command using PDO protocol
  • The input value should be the default unit (velocity = rpm, position = steps) from the board. Do not expect same unit from the publisher.

• /state_change (adi_tmc_coe/state_change)
  • Changes state of the specified device/slave

• /cyclic_sync_mode (adi_tmc_coe/CSx_mode)
  • Controls the motor’s velocity, position or torque in cyclic synchronous mode.
  • The input value should be the default unit (velocity = rpm, position = steps) from the board. Do not expect same unit from the publisher.

Parameters

:memo: Notes:

• _Communication Interface Parameter is essential in initializing etherCAT.
• _The node is expected to exit if interface_name is not set/declared, the rest of parameters are okay if not set/declared, default values will be used. _
• ROS parameters can only cover rosparam get. rosparam set is prohibited, even when the user run rosparam set, only the parameters from server will change but not in the node itself

Communication Interface Parameter

• interface_name (string)
  • Name of the NIC (Network Interface Card) detected by the PC. Use command $ifconfig to check the interface name, it usually starts with ethxxx or enxxxx.
• SDO_PDO_retries (int, default: 3)
  • Indicates how many times the SDO and PDO will retry in sending before logging an error if SDO or PDO fails.
• interface_timeout (double, default: 3.0)
  • Indicates how long should the node will wait for the slave to be responsive.

TMC COE ROS Node Parameters

• en_slave (int[], default: [0])
  • Enables/disables device/slave connected. If disabled, settings for those motors will be ignored or not set.
• adhoc_mode (int[], default: [0])
  • This mode expects that the used module is not known. The velocity, position and torque relies on the additional_ratio_* values.
• en_motors (int[], default: [0])
  • Enables/disables active motors or axes. If disabled, settings for those motors will be ignored or not set.

Motor Configuration Settings

• pub_rate_tmc_coe_info (float, default: 10)
  • Publish rate (hertz) of TMC information
• en_pub_tmc_coe_info (bool, default: false)
  • Enables/disables publishing of TMC information
• pub_actual_vel (bool, default: false)
  • Enable/Disable actual velocity that the user can optionally publish every publish rate as long as en_pub_tmc_info is true
• pub_actual_pos (bool, default: false)
  • Enable/Disable actual position that the user can optionally publish every publish rate as long as en_pub_tmc_info is true
• pub_actual_trq (bool, default: false)
  • Enable/Disable actual torque that the user can optionally publish every publish rate as long as en_pub_tmc_info is true
• tmc_coe_info_topic (string, default: /tmc_coe_info__)
  • tmc_coe_info topics that will contain chosen TMC info that will be published
• tmc_cmd_vel_topic (string, default: /cmd_vel__)
  • Twist topics that will be the source of target velocity to be set on the TMC
• tmc_cmd_abspos_topic (string, default: /cmd_abspos__)
  • Int32 topics that will be the source of target position to be set on the TMC
• tmc_cmd_relpos_topic (string, default: /cmd_relpos__)
  • Int32 topics that will be the source of target position to be set on the TMC
• wheel_diameter (float, default: 0)
  • Wheel diameter that is attached on the motor shaft directly. This is to convert linear values to rpm
  • If wheel diameter is 0, cmd_vel is equal to rpm
• additional_ratio_vel (float, default: 1)
  • Additional Ratio for velocity for general purposes (adhoc mode, added pulley or gear trains). Default value 1 means disabled
• additional_ratio_pos (float, default: 1)
  • Additional Ratio for position for general purposes (adhoc mode, added pulley or gear trains). Default value 1 means disabled
• additional_ratio_trq (float, default: 1)
  • Additional Ratio for torque for general purposes (adhoc mode). Default value 1 means disabled

Quick Tests

Test Velocity Mode

To do a quick test of Velocity Mode, there is a fake velocity script that the user can run. Idea is, this script will send Velocity commands (as a ROS topic), then the first motor should be expected to:

1. Increase velocity every 3secs, clockwise (in m/s: 3, 6, 9)
2. Stop for 5secs
3. Increase velocity every 3secs, counter-clockwise (in m/s: -3, -6, -9)
4. Stop for 5secs

To proceed with the test, execute these following commands on three (3) different terminals (in sequence):

Monitor the velocity of the first motor (watch out for velocity value at Terminal 2).

:memo: Notes:

• Terminals 2 and 3 are best viewed side-by-side.
• You may Ctrl-C the command in Terminal 2 once you’re done.
• The command in Terminal 3 auto-stops by itself.

Test Position Mode

To do a quick test of Position Mode, there is a fake position script that the user can run. Idea is, this script will send Position commands (as a ROS topic), then the first motor should be expected to:

1. Rotate 360 degrees (clockwise) every 5 secs, 3 times
2. Stop for 5secs
3. Rotate 360 degrees (counter-clockwise) every 5 secs, 3 times
4. Stop for 5secs

To proceed with the test, execute these following commands on three (3) different terminals (in sequence):

Monitor the position of the first motor (watch out for position value at Terminal 2).

:memo: Notes:

• Terminals 2 and 3 are best viewed side-by-side.
• You may Ctrl-C the command in Terminal 2 once you’re done.
• The command in Terminal 3 auto-stops by itself.

Limitations

1. Current modules that are tested does not include Profile Torque Mode but still included on topic names for ease of implementation if decided to continue.
2. Homing Mode is not implemented.
3. Cyclic Synchronous Modes only accepts raw value (no conversions of unit) and is not the same with subscriber callbacks.
4. Host PC specifications play a crucial role to ensure low latency when exchanging data. 4 or more cores are recommended. Threads will increase depending on the number of devices/slaves and motors.
5. Due to having and allowing multiple threads (e.g. 1 thread for processdata cycle, 1 thread that executes SDOread/write), a ~0.01s delay was added in each SDOread/write retries to ensure proper processing.

License

This project is licensed under the BSD-3 Clause.

Notice

Please refer to the NOTICE file for details on third-party libraries and attributions.

Support

Please contact the Maintainers if you want to use this ROS Driver on Trinamic Motor Controllers without YAML files in this repository.

Any other inquiries and support are also welcome.