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Package Summary

Tags No category tags.
Version 0.5.18
License LGPLv3
Build type CATKIN
Use RECOMMENDED

Repository Summary

Checkout URI https://github.com/PilzDE/pilz_robots.git
VCS Type git
VCS Version melodic-devel
Last Updated 2020-07-13
Dev Status DEVELOPED
CI status
Released RELEASED
Package Tags No category tags.
Contributing Help Wanted (0)
Good First Issues (0)
Pull Requests to Review (0)

Package Description

Control hardware functions of the PRBT manipulator like RUN_PERMITTED for Stop1 functionality.

Additional Links

Maintainers

  • Alexander Gutenkunst
  • Christian Henkel
  • Hagen Slusarek
  • Immanuel Martini

Authors

No additional authors.

Table of Contents

Introduction

The prbt_hardware_support package provides support for the Pilz hardware PNOZmulti and PSS 4000. A number of safety features are provided which are essential for a DIN EN ISO 10218-1 certifiable robot system (for more information see section about supported DIN EN ISO 10218-1 safety features).

Due to the fact, that the communication between the Pilz safety controllers and ROS is based on the Modbus communication protocol, the package also contains C++ files providing ROS support for the Modbus communication protocol.

In the system overview section, you can find a component diagram showing the overall architecture of our system. The component diagram shows all our nodes and the connections between them.

Please note:
The launch files included in the prbt_hardware_support package don't need to be called directly by the user. They already are included in our top-level launch file (for more information on how-to run the PRBT robot with ROS see the pilz_robots-README and our application templates.

Supported DIN EN ISO 10218-1 safety features

The prbt_hardware_support package provides support for a number of safety features which are essential for a DIN EN ISO 10218-1 certifiable robot system.

Please note:
The DIN EN ISO 10218-1 support is currently WORK IN PROGRESS.

Needed/supported hardware

In order for the safety features to work, one needs special hardware components supporting the required safety features. Currently, we test all our features against the following hardware setup: - Robot: Manipulator module PRBT 6 - Safety controller: PSS 4000 (with a dedicated program) - Operating mode selector switch: PITmode - Enabling switch: PITenable - Pushbutton unit (with emergency stop): PITgatebox

How-to activate and deactivate hardware features

The following table shows the names and the possible argument values of the features supported by our hardware. The features can be configured via arguments of prbt_support/launch/robot.launch.

Parameter Description Argument name in robot.launch Possible values in robot.launch
Gripper Model gripper <arg unset>, pg70
Safety Controller Hardware safety_hw pss4000, pnoz
Brake Test Support has_braketest_support true, false
Operation Mode Support has_operation_mode_support true, false
Visual Status Indicator visual_status_indicator true, false

With pg70 referring to Schunk PG plus 70. For more on gripper models see prbt_grippers.

The optional argument iso10218_support can be used to start ROS without connecting to a safety controller. Keep in mind that this disables all safety features, so it should only be used for debugging purposes.

Currently, we only support the following configurations depending on the safety controller. If the safety controller is changed, please ensure that the arguments are set as shown in the table.

Argument name Default value with PSS400 Default value with PNOZmulti
safety_hw pss4000 pnoz
has_braketest_support true false
has_operation_mode_support true true
visual_status_indicator true true

Definitions

RUN_PERMITTED signal

The RUN_PERMITTED is a state required in the safety controller for the robot to operate. It is sent to the ROS system to inform it in the case of an upcoming STO of the robot.

Please note: The ROS nodes only react on changes of the signal, so it may be necessary to re-trigger RUN_PERMITTED in order to enable the drives at start.

STO

The STO function (“Safe torque off”) of the robot arm is a safety function to immediately turn off torque of the drives. The behavior triggers the RUN_PERMITTED signal.

SBC

The SBC function ("Safe brake control") of the robot arm is a safety function which is used in conjunction with the RUN_PERMITTED and prevents a motion when the torque of the drives is turned off.

Safe stop 1 (SS1)

To allow a controlled stop, the safety controller delays the STO signal by several milliseconds. The STO signal, otherwise, would lead to an immediate stop of the robot via Stop 0. The time delay gives the ros_control time to stop the drives with a well defined brake ramp.
The safety controller informs the ros_control about the stop request via Modbus connection. The Modbus connection is opened by this package.
After the execution of the brake ramp, the drivers are halted.

Please note:
Should ROS fail (for what ever reason), the safety controller still ensures that the robot is stopped by executing a Stop 0. The Stop 0 is executed after the above described time delay.

Brake test

Brake tests are an integral part of the safe brake control (SBC) functionality, since they detect malfunctions of the brakes or the brake control in general. Brake tests for each drive have to be executed at a regular interval. When the safety controller requests brake tests, they have to be executed within 1 hour, else the robot cannot be moved anymore.

Operation Modes

The robot system can be controlled in various modes.

These modes are: - T1: Speed reduced to 250 mm/s (each robot-frame), enabling switch must be pressed - T2*: The robot moves at full speed but still the enabling switch must be pressed - AUTOMATIC: The robot moves at full speed and follows a predefined program/process. No enabling switch is needed but safety has to be ensured by safety peripherie (fences, light curtains, ...).

See DIN EN ISO 10218-1 for more details or contact us: ros@pilz.de

Please note:
In operation mode T1 the robot can be moved as usual. However, if an attempt to exceed the speed limit of 250 mm/s in T1 is detected, the current motion is aborted and a controlled stop is performed. For more information see the speed monitoring section.

Speed monitoring

DIN EN ISO 10218-1 requires that in operation mode T1 no part of the robot moves faster than 250 mm/s. To meet this requirement, the PilzJointTrajectoryController checks the target velocity for each robot-frame. If one or more robot-frames exceed the allowed speed limit, the controller executes a safe stop 1. (For more information about the safe stop 1, see safe stop 1 section).
To re-enable the system, the user needs to release and, subsequently, press the enabling switch.

Please note:
Currently, only one of the PILZ controllers, namely the PilzJointTrajectoryController, can perform the speed monitoring required by DIN EN ISO 10218-1.

Possible error cases and their handling

Error cases Handling
Modbus client crashes ROS system is shutdown which leads to an abrupt stop of the robot.
RUN_PERMITTED Modbus adapter crashes ROS system is shutdown which leads to an abrupt stop of the robot.
Connection loss between PNOZmulti/PSS4000 & Modbus client Stop 1 is triggered
System overload (messages don't arrive in time) In case a Stop 1 message does not arrive in time, the safety controller will automatically perform a hard stop. In case a Stop 1-release message does not get through, brakes will remain closed.
RUN_PERMITTED Modbus adapter cannot connect to stop services ROS system will not start.
RUN_PERMITTED Modbus adapter cannot connect to recover services Node does start and robot can be moved until a stop is triggered. Afterwards the brakes will remain closed.

Overview system components

The following diagram shows all components of the system and the connections between them.

Component diagram of overall architecture

ModbusClient

A Modbus client (for usage with the PNOZmulti or PSS4000) can be started with roslaunch prbt_hardware_support modbus_client.launch.

Published Topics

  • ~/pilz_modbus_client_node/modbus_read (prbt_hardware_support/ModbusMsgInStamped)
    • Holds information about the modbus holding register. Timestamp is only updated if the register content changed.

Parameters

  • modbus_server_ip
  • modbus_server_port
  • index_of_first_register_to_read
  • num_registers_to_read
  • modbus_connection_retries (default: 10)
  • modbus_connection_retry_timeout - timeout between retries (default: 1s)
  • modbus_response_timeout (default: 20ms)
  • modbus_read_topic_name (default: "/pilz_modbus_client_node/modbus_read")
  • modbus_write_service_name (default: "/pilz_modbus_client_node/modbus_write")

Please note: - The parameters modbus_response_timeout and modbus_read_topic_name are important for the Safe stop 1 functionality and must NOT be given, if the pilz_modbus_client_node is used as part of the Safe stop 1 functionality. If the parameters are not given the default values for these parameters are used.

ModbusAdapterRunPermittedNode

The ModbusAdapterRunPermitted is noticed via the topic /pilz_modbus_client_node/modbus_read if the RUN_PERMITTED is true or false and reacts as follows calling the corresponding services of the controllers and drivers: - RUN_PERMITTED true: enable drives, unhold controllers - RUN_PERMITTED false: hold controllers, disable drives

ModbusAdapterBrakeTestNode

The ModbusAdapterBrakeTestNode offers the /prbt/brake_test_required service which informs if the PSS4000 requests a brake test or if a brake test request is no longer prevailing.

BraketestExecutorNode

The BraketestExecutorNode offers the /execute_braketest service which, in interaction with the CanOpenBraketestAdapter, executes a braketest on each drive of the manipulator. This can only be done, if the robot is stopped. So, if you want to execute a braketest, ensure that the robot stands still.

ModbusAdapterOperationModeNode

The ModbusAdapterOperationModeNode publishes the active operation mode on the topic /prbt/operation_mode everytime it changes and offers the /get_operation_mode service for accessing the active operation mode.

Use rosmsg show prbt_hardware_support/OperationModes to see the definition of each value.

OperationModeSetupExecutorNode

The OperationModeSetupExecutorNode activates the speed monitoring for operation mode T1 and offers a service /prbt/get_speed_override. The speed override is chosen such that a speed limit violation is unlikely if all robot motions are scaled with it.

*Not supported yet

CHANGELOG

Changelog for package prbt_hardware_support

0.5.18 (2020-07-02)

  • Make AsyncTest header-only
  • Move modbus connection checker function in separate file
  • Contributors: Pilz GmbH and Co. KG

0.5.17 (2020-06-22)

  • Infinite modbus connection retries
  • Improved modbus error messages
  • New modbus api
  • Refactor components to use Cartesian speed monitor functionality in controller
  • Contributors: Pilz GmbH and Co. KG

0.5.16 (2020-05-15)

  • Update and apply clang-format (#387)
  • Make test-subfolder-names consistent (#380)
  • Extend stop1 acceptance test (#378)
  • Fix namespace in launch-file (#383)
  • Contributors: Pilz GmbH and Co. KG

0.5.15 (2020-05-03)

  • Add support for starting the robot without modbus
  • sto for hw definition is now called safety_hw everywhere
  • Moved system_info_node to prbt_support
  • Adopted default configuration for launchfiles
  • Renaming of STO into RUN_PERMITTED
  • Enable starting ROS without modbus connection
  • Contributors: Pilz GmbH and Co. KG

0.5.14 (2020-03-11)

  • Trim firmware string.
  • Rename waitForTopic() -> waitForMessage()
  • Add Status Indicator that shows operation mode, speed override, HW status and ROS status
  • Contributors: Pilz GmbH and Co. KG

0.5.13 (2019-12-04)

  • Use brake-test definitions from pilz_msgs
  • Contributors: Pilz GmbH and Co. KG

0.5.12 (2019-11-28)

  • Remove srv definition for speed override (moved to the package pilz_msgs)
  • Contributors: Pilz GmbH and Co. KG

0.5.11 (2019-11-22)

  • Fix clang compiler errors (#283)
  • Contributors: Pilz GmbH and Co. KG

0.5.10 (2019-10-08)

  • Add missing dependency on tf2_geometry_msgs (#264)
  • Minor fixes
  • Contributors: Pilz GmbH and Co. KG

0.5.9 (2019-10-07)

  • Add service for getting the global speed override
  • Add modbus register for enabling temporary movement
  • Add Frame speed monitoring
  • Test fixes and improvements
  • Contributors: Pilz GmbH and Co. KG
  • Add speed observing dependent on operation mode
  • Contributors: Pilz GmbH and Co. KG

0.5.8 (2019-09-10)

  • add missing transition to RUN_PERMITTED state machine
  • revise RUN_PERMITTED specification
  • integrate clang-tidy via CMake flag
  • Contributors: Pilz GmbH and Co. KG

0.5.7 (2019-08-29)

  • Add state machine for RUN_PERMITTED handling to allow skipping of hold/unhold if needed
  • add operation mode functionality
  • add write capability to PilzModbusReadClient, rename PilzModbusReadClient -> PilzModbusClient
  • enter hold mode at braketest execution
  • automatically determine range for reading modbus registers
  • only read modbus registers that are explicitly configured (not in a single block)
  • separate api definitions for read and write
  • brake test result can be sent to FS controller
  • Contributors: Pilz GmbH and Co. KG

0.5.6 (2019-06-12)

  • Essentially reverts wrong fix (depend on canopen_chain_node) from 0.5.5

0.5.5 (2019-06-12)

  • Add missing depend (CATKIN_DEPENDS and <run_depend>) on canopen_chain_node

0.5.4 (2019-05-27)

  • increased modbus response timeout to 20ms
  • publish brake test requests obtained from safety controller via modbus
  • run_permitted_modbus_adapter waits for the services to appear instead of throwing exceptions
  • Add ability to execute a braketest on each drive.
  • Add service to access the active operation mode
  • Contributors: Pilz GmbH and Co. KG

0.5.3 (2019-04-24)

  • cleanup CMakeLists of prbt_hardware_support
  • update the documentation
  • more precise error output when failing to read modbus register
  • Contributors: Pilz GmbH and Co. KG

0.5.2 (2019-02-21)

  • Update used pipeline in test from command_planner to pilz_command_planner
  • Fix PilzModbusReadClient unittest
  • Contributors: Pilz GmbH and Co. KG

0.5.1 (2018-11-30)

  • melodic release based on kinetic version 0.4.3
  • Contributors: Pilz GmbH and Co. KG

0.5.0 (2018-11-07)

0.4.3 (2018-11-30)

0.4.2 (2018-11-08)

  • Fix missing include on std_srvs

0.4.1 (2018-11-07)

  • Use Modbus API v2 due to wrongly specified version 1

0.4.0 (2018-11-06)

  • Modbus client node and RUN_PERMITTED modbus adapter node for Stop 1 functionality

Wiki Tutorials

See ROS Wiki Tutorials for more details.

Source Tutorials

Not currently indexed.

Launch files

  • launch/safety_interface.launch
    • Copyright (c) 2020 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
      • safety_hw [default: pss4000]
      • read_api_spec_file [default: $(find prbt_hardware_support)/config/modbus_read_api_spec_$(arg safety_hw).yaml]
      • write_api_spec_file [default: $(find prbt_hardware_support)/config/modbus_write_api_spec_$(arg safety_hw).yaml]
      • modbus_server_ip [default: $(eval '192.168.0.10' if safety_hw=='pss4000' else '169.254.60.1')]
      • has_braketest_support [default: true]
      • has_operation_mode_support [default: true]
  • launch/operation_mode_setup_executor_node.launch
    • Copyright (c) 2019 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
  • launch/stop1_executor_node.launch
    • Copyright (c) 2019 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
  • launch/canopen_braketest_adapter_node.launch
    • Copyright (c) 2019 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
  • launch/modbus_adapter_brake_test_node.launch
    • Copyright (c) 2019 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
      • write_api_spec_file [default: $(find prbt_hardware_support)/config/modbus_write_api_spec_pss4000.yaml]
  • launch/brake_test_executor_node.launch
    • Copyright (c) 2019 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
  • launch/fake_safety_interface.launch
    • Copyright (c) 2019 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
  • launch/modbus_adapter_run_permitted_node.launch
    • Copyright (c) 2018 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
  • launch/brake_test.launch
    • Copyright (c) 2019 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
      • write_api_spec_file [default: $(find prbt_hardware_support)/config/modbus_write_api_spec_pss4000.yaml]
  • launch/fake_operation_mode_setup.launch
    • Copyright (c) 2020 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
      • controller_name [default: manipulator_joint_trajectory_controller]
  • launch/modbus_adapter_operation_mode_node.launch
    • Copyright (c) 2019 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
  • launch/modbus_client.launch
    • Copyright (c) 2018 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
      • modbus_server_ip [default: 192.168.0.10]
      • modbus_server_port [default: 502]
      • index_of_first_register_to_read [default: ]
      • num_registers_to_read [default: ]
      • safety_hw [default: pss4000]
  • launch/operation_mode.launch
    • Copyright (c) 2019 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .

Plugins

No plugins found.

Recent questions tagged prbt_hardware_support at answers.ros.org

Package Summary

Tags No category tags.
Version 0.4.12
License LGPLv3
Build type CATKIN
Use RECOMMENDED

Repository Summary

Checkout URI https://github.com/PilzDE/pilz_robots.git
VCS Type git
VCS Version kinetic-devel
Last Updated 2020-04-08
Dev Status DEVELOPED
CI status Continuous Integration
Released RELEASED
Package Tags No category tags.
Contributing Help Wanted (0)
Good First Issues (0)
Pull Requests to Review (0)

Package Description

Control hardware functions of the PRBT manipulator like RUN_PERMITTED for Stop1 functionality.

Additional Links

Maintainers

  • Alexander Gutenkunst
  • Christian Henkel
  • Hagen Slusarek
  • Immanuel Martini

Authors

No additional authors.

Overview

The prbt_hardware_support package contains files supporting the certification of a robot system including the PRBT manipulator according to DIN EN ISO 10218-1. As safety controllers the Pilz hardware PNOZmulti and PSS4000 are supported. A Modbus connection is used for the communication between ROS <-> safety controller.

There is no need to call these launch files directly; they are included from prbt_support/launch/robot.launch.

How-to activate and deactivate hardware features

The following table shows the names and the possible argument values of the features supported by our hardware. The features can be configured via arguments of prbt_support/launch/robot.launch.

Parameter Description Argument name in robot.launch Possible values in robot.launch
Gripper Model gripper <arg unset>, pg70
Safety Controller Hardware safety_hw pss4000, pnoz
Brake Test Support has_braketest_support true, false
Operation Mode Support has_operation_mode_support true, false
Visual Status Indicator visual_status_indicator true, false

With pg70 referring to Schunk PG plus 70. For more on gripper models see prbt_grippers.

Currently, we only support the following configurations depending on the safety controller. If the safety controller is changed, please ensure that the arguments are set as shown in the table.

Argument name Default value with PSS400 Default value with PNOZmulti
safety_hw pss4000 pnoz
has_braketest_support true false
has_operation_mode_support true true
visual_status_indicator true true

Safety Features

Safe torque off function

The Safe torque off (STO) function of the robot arm is a safety function to immediately turn off torque of the drives. The behavior triggers the RUN_PERMITTED signal.

Run permitted signal

The RUN_PERMITTED is a state required in the safety controller for the robot to operate. It is sent to the ROS system to inform it in the case of an upcoming STO of the robot.

Safe brake control

The SBC function (Safe brake control) of the robot arm is a safety function which is used in conjunction with the RUN_PERMITTED and prevents a motion when the torque of the drives is turned off.

Safe stop 1 (SS1)

To allow a controlled stop, the safety controller delays the STO function by several milliseconds. This package opens a modbus connection to the safety controller (PNOZmulti or PSS4000). The safety controller sends a RUN_PERMITTED=false signal via Modbus immediately so that ros_control has a short time interval to stop the drives via a brake ramp. The TCP could for example brake on the current trajectory. After execution of the brake ramp, the drivers are halted. Even if ROS would fail, the safety controller turns off the motors via STO (that would be a Stop 0 then).

Brake tests

Brake tests are an integral part of the SBC, since they detect malfunction of the brakes or the brake control in general. Brake tests for each drive have to be executed at a regular interval. When the safety controller requests brake tests, they have to be executed within 1 hour, else the robot cannot be moved anymore.

Operation Modes

The robot system can be controlled in various modes.

These modes are: - T1: Speed reduced to 250 mm/s (each robot-frame), enabling switch must be pressed - T2*: The robot moves at full speed but still the enabling switch must be pressed - AUTOMATIC: The robot moves at full speed and follows a predefined program/process. No enabling switch is needed but safety has to be ensured by safety peripherie (fences, light curtains, ...).

See DIN EN ISO 10218-1 for more details or contact us: ros@pilz.de

Note

In operation mode T1 the robot can be moved as usual. However, if an attempt to exceed the speed limit of 250 mm/s in T1 is detected, the prevailing motion is aborted and a controlled stop is performed.

Possible error cases and their handling

Error cases Handling
Modbus client crashes ROS system is shutdown which leads to an abrupt stop of the robot.
RUN_PERMITTED Modbus adapter crashes ROS system is shutdown which leads to an abrupt stop of the robot.
Connection loss between PNOZmulti/PSS4000 & Modbus client Stop 1 is triggered
System overload (messages don't arrive in time) In case a Stop 1 message does not arrive in time, the safety controller will automatically perform a hard stop. In case a Stop 1-release message does not get through, brakes will remain closed.
RUN_PERMITTED Modbus adapter cannot connect to stop services ROS system will not start.
RUN_PERMITTED Modbus adapter cannot connect to recover services Node does start and robot can be moved until a stop is triggered. Afterwards the brakes will remain closed.

Architecture

The following diagram shows all components of the system and the connections between them.

Component diagram of overall architecture

ROS API

ModbusClient

A Modbus client (for usage with the PNOZmulti or PSS4000) can be started with roslaunch prbt_hardware_support modbus_client.launch.

Published Topics

  • ~/pilz_modbus_client_node/modbus_read (prbt_hardware_support/ModbusMsgInStamped)
    • Holds information about the modbus holding register. Timestamp is only updated if the register content changed.

Parameters

  • modbus_server_ip
  • modbus_server_port
  • index_of_first_register_to_read
  • num_registers_to_read
  • modbus_connection_retries (default: 10)
  • modbus_connection_retry_timeout - timeout between retries (default: 1s)
  • modbus_response_timeout (default: 20ms)
  • modbus_read_topic_name (default: "/pilz_modbus_client_node/modbus_read")
  • modbus_write_service_name (default: "/pilz_modbus_client_node/modbus_write")

Please note: - The parameters modbus_response_timeout and modbus_read_topic_name are important for the Safe stop 1 functionality and must NOT be given, if the pilz_modbus_client_node is used as part of the Safe stop 1 functionality. If the parameters are not given the default values for these parameters are used.

ModbusAdapterRunPermittedNode

The ModbusAdapterRunPermitted is noticed via the topic /pilz_modbus_client_node/modbus_read if the RUN_PERMITTED is true or false and reacts as follows calling the corresponding services of the controllers and drivers: - RUN_PERMITTED true: enable drives, unhold controllers - RUN_PERMITTED false: hold controllers, disable drives

ModbusAdapterBrakeTestNode

The ModbusAdapterBrakeTestNode offers the /prbt/brake_test_required service which informs if the PSS4000 requests a brake test or if a brake test request is no longer prevailing.

BraketestExecutorNode

The BraketestExecutorNode offers the /execute_braketest service which, in interaction with the CanOpenBraketestAdapter, executes a braketest on each drive of the manipulator. This can only be done, if the robot is stopped. So, if you want to execute a braketest, ensure that the robot stands still.

ModbusAdapterOperationModeNode

The ModbusAdapterOperationModeNode publishes the active operation mode on the topic /prbt/operation_mode everytime it changes and offers the /get_operation_mode service for accessing the active operation mode.

Use rosmsg show prbt_hardware_support/OperationModes to see the definition of each value.

OperationModeSetupExecutorNode

The OperationModeSetupExecutorNode sets the speed limit for each frame based on the active operation mode and offers a service /prbt/get_speed_override. The speed override is chosen such that a speed limit violation is unlikely if all robot motions are scaled with it.

Parameters

  • speed_limit_t1 m/s
  • speed_limit_automatic m/s

SpeedObserverNode

The SpeedObserverNode observes the speed of the robot frames and triggers a controlled stop, if the current speed limit is exceeded.

Parameters

  • frequency Hz
  • additional_frames (optional): lets the user specify frames to observe in addition to the robot frames of the prevailing robot model

*Not supported yet

CHANGELOG

Changelog for package prbt_hardware_support

Forthcoming

  • Adopted default configuration for launchfiles
  • Renaming of STO into RUN_PERMITTED
  • Contributors: Pilz GmbH and Co. KG

0.4.12 (2020-03-24)

  • Trim firmware string.
  • Rename waitForTopic() -> waitForMessage()
  • Add Status Indicator that shows operation mode, speed override, HW status and ROS status
  • Add missing dependency on tf2_geometry_msgs (#264)
  • Add service for getting the global speed override
  • Add modbus register for enabling temporary movement
  • Add Frame speed monitoring
  • Test fixes and improvements
  • Add speed observing dependent on operation mode
  • Contributors: Pilz GmbH and Co. KG

0.4.11 (2019-09-11)

  • add missing transition to STO state machine
  • revise STO specification
  • integrate clang-tidy via CMake flag
  • Contributors: Pilz GmbH and Co. KG

0.4.10 (2019-09-03)

  • Add state machine for STO handling to allow skipping of hold/unhold if needed
  • add operation mode functionality
  • add write capability to PilzModbusReadClient, rename PilzModbusReadClient -> PilzModbusClient
  • enter hold mode at braketest execution
  • automatically determine range for reading modbus registers
  • only read modbus registers that are explicitly configured (not in a single block)
  • separate api definitions for read and write
  • brake test result can be sent to FS controller
  • Contributors: Pilz GmbH and Co. KG

0.4.9 (2019-06-19)

  • increased modbus response timeout to 20ms
  • publish brake test requests obtained from safety controller via modbus
  • sto_modbus_adapter waits for the services to appear instead of throwing exceptions
  • Add ability to execute a braketest on each drive.
  • Contributors: Pilz GmbH and Co. KG

0.4.8 (2019-04-24)

  • cleanup CMakeLists of prbt_hardware_support
  • update the documentation
  • Contributors: Pilz GmbH and Co. KG

0.4.7 (2019-02-15)

  • drop outdated can configuration
  • Contributors: Pilz GmbH and Co. KG

0.4.6 (2019-01-18)

  • Update used pipeline in test from command_planner to pilz_command_planner

0.4.5 (2019-01-16)

0.4.4 (2019-01-16)

  • Fix PilzModbusReadClient unittest

0.4.3 (2018-11-30)

0.4.2 (2018-11-08)

  • Fix missing include on std_srvs

0.4.1 (2018-11-07)

  • Use Modbus API v2 due to wrongly specified version 1

0.4.0 (2018-11-06)

  • Modbus client node and STO modbus adapter node for Stop 1 functionality

Wiki Tutorials

See ROS Wiki Tutorials for more details.

Source Tutorials

Not currently indexed.

Launch files

  • launch/operation_mode_setup_executor_node.launch
    • Copyright (c) 2019 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
      • speed_limit_t1 [default: 0.25]
      • speed_limit_automatic [default: 5.0]
  • launch/stop1_executor_node.launch
    • Copyright (c) 2019 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
  • launch/canopen_braketest_adapter_node.launch
    • Copyright (c) 2019 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
  • launch/speed_observer_node.launch
    • Copyright (c) 2019 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
      • frequency [default: 20]
  • launch/modbus_adapter_brake_test_node.launch
    • Copyright (c) 2019 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
      • write_api_spec_file [default: $(find prbt_hardware_support)/config/modbus_write_api_spec_pss4000.yaml]
  • launch/brake_test_executor_node.launch
    • Copyright (c) 2019 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
  • launch/fake_safety_interface.launch
    • Copyright (c) 2019 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
  • launch/modbus_adapter_run_permitted_node.launch
    • Copyright (c) 2018 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
      • index_of_first_register_to_read [default: 512]
  • launch/brake_test.launch
    • Copyright (c) 2019 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
      • write_api_spec_file [default: $(find prbt_hardware_support)/config/modbus_write_api_spec_pss4000.yaml]
  • launch/modbus_adapter_operation_mode_node.launch
    • Copyright (c) 2019 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
  • launch/modbus_client.launch
    • Copyright (c) 2018 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .
      • modbus_server_ip [default: 192.168.0.10]
      • modbus_server_port [default: 502]
      • index_of_first_register_to_read [default: ]
      • num_registers_to_read [default: ]
      • safety_hw [default: pss4000]
  • launch/operation_mode.launch
    • Copyright (c) 2019 Pilz GmbH & Co. KG This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see .

Plugins

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