bus_server

The bus_server module is one of many firmware side pieces of code used in the Ubiquity Robotics platforms that use a ROS Arduino Bridge subsystem such as Loki and Freya.

These commands are in general a subset of the official ROS Arduino Bridge commands with other commands added that use letters not defined by the official ROS Arduino Package as seen in ROS Hydra.

This readme is meant to document the commands that are received by bus_server and then processed here or in other modules. The bus_server is the place where serial API is presented through the uart interface.

Firmware Commands For Ubiquity Robotics Implementation

The single-letter commands over the serial port are used for polling sensors, controlling servos, driving the robot, and reading encoders. These commands can be sent to the Arduino over any serial interface, including the Serial Monitor in the Arduino IDE.

NOTE: Before trying these commands, set the Serial Monitor baudrate to 115200 and the line terminator to “Carriage return” or “Both NL & CR” using the two pulldown menus on the lower right of the Serial Monitor window.

Command Name   Cmd  Parms     Description
GET_BAUDRATE    b             Return baud rate (often used as a quick test or ping)
READ_ENCODERS   e             Return the current reading of the two wheel encoders
MOTOR_SPEEDS    m L R         Set motor speeds for left and right to be controlled by PID
PING            p S           Read one sonar sensor starting with sensor 1.  0 returns all.
RESET_ENCODERS  r             Reset encoder values both to 0
UPDATE_PID      u Kp Kd Ki Ko Update PID parameters with 
VERBOSE_DEBUG   v F           Set single bit flags to enable assorted debug modes 
MOTOR_DIRECT    z L R         Set motor speeds for left and right directly -126 to +126

Note: Commands of   a,c,d,s,t,w, and x are NOT supported in this firmware

Changelog for package bus_server

0.2.2 (2018-02-04)

• Publish all sonars on a single topic /sonars, in addition to individual topics
• Contributors: Jim Vaughan

0.2.1 (2017-12-30)

• fix cmake error from rename
• Contributors: Rohan Agrawal

0.2.0 (2017-12-30)

• change package name from bus_server to loki_base_node
• Contributors: Rohan Agrawal

0.1.1 (2016-04-14)

• Added minor travis stuff
• Contributors: Rohan Agrawal

0.1.0 (2016-01-17)

• Added sonar statistics install rule
• Updated package.xml
• Added install rules to make sure python scripts are runnable in non-devel environments (such as installing from debs)
• Changed minimum sensor range to .15
• Fixed typo for /dev/ttyAMA0
• Merged
• Fixed /dev/ttyACM0=>/dev/ttyAMA0
• Use default ports if no port parameter is specified.
• Got dynamic sonar scheduling to work.
• Continuing to work on Sonars.
• Changed the strategy for managing clock skew between the robot and ROS.
• Added class/left_id/right_id fields to each Sonar. These can be specified in the .yaml file and get reflected by bus_server.py to through to the robot firmware. These fields are needed for dynamic sonar scheduling.
• Updated the descriptive text at the beginning of bus_server.py .
• Added Twist (cmd_vel) and transfer PID parameters to robot.
• Merge branch 'master' of https://github.com/UbiquityRobotics/bus_server
• Got odometry work in bus_server.py.
• Got odometry working.
• Refactored dead reckoning code into Dead_Reckon class.
• Merge branch 'master' of https://github.com/UbiquityRobotics/bus_server
• Backing down PID loop debug to minimal
• Merge branch 'master' of https://github.com/UbiquityRobotics/bus_server
• Got sonar sensers to publish range topics all the way to RViz.
• Increase PID rate and fix problem with initial going backwards at slow speeds. Also have debug serial to the bus_uart in PID loop which is on for now but can be disabled.
• Fixed typo with a duplicate left encoder set.
• Started adding sonar support to bus_server.py.
• Added in accidentally deleted code that sets encoders in PID code chunk. Me bad.
• Rearranged bus_server.py to have all of the imports in one place. Added main() and made the last line of code in the file run main().
• Created bus_server.py by concatenating all of the ROS Aduino bridge python files into one. This code will not work.
• Added sonars to queue command.
• Added q command to bus server. Some minor clean up on encoder interface.
• Making the Do PID param be Ko as other places like that term more. No actual functional change with this cleanup
• Change PID loop rate to 10 hz and put command u for pin params in order of Kp Kd Ki Do Ci to better match how it was before Ci appeared. also if we use 'u 1' with less than 5 params we print params and don't set them.
• Removed concept of unit number for sonars.
• Refactored the code so that Sonar.{h,cpp} no longer needs RAB_Sonar{h,cpp}. This touched a bunch of files.
• Removed pin definitions from bus_loki and Sonar.
• Removed unused and unneed encoder registers from bus_sonar10.
• Got bus_sonar10 to return ficticious sonar data over the bus.
• Refactored bus_server, bus_loki, and bus_freya to add the RAB_Sonar class. This is prepatory work for bus_sonar10.
• Change pid update to 25hz from 5hz. Add cap for speeds in z command. Change the debug PID override mode so you must set debug flag to enable PID override when Kp is 0 so we can better tune pid without it interfering. IMPORTANT: Adding integral cap term so the u command has 5 terms now as Kp Kd Ki Ci Do where new term is Ci as integral cap to avoid runaway integral term issues
• Adding description of serial commands we support
• Adding description of serial commands we support
• Added a debug to support periodic print of sonar meas error counters for minimally evasive debug
• Return distances in Cm now per correct way ROS expects the values
• Switch the p command to read from cached in-ram prior measurements. Added back in the o which does inline measurement. Returned values for Sonar are still in mm.
• Changed 'o' command to 'p' command.
• Adding system_debug_flags for dynamic changing of what is printed to serial port. Should act like before by default is the intention. Flags in bus_server.h
• Fixes to non-PID motor control when Kp is set to 0 and support for reading all sonars or just one using o command
• Renamed x command to z command. z command sets the motor speeds without using PID loop.
• Removed some debugging code. Removed a minus sign on the right motor speed.
• Got Loki encoders working.
• Upgrade to new Bus_Motor_Encoder API that has encoder get/set and pwm set methods.
• Wrapped up Bridge object conversion.
• More conversion over to Bridge object.
• Started transition over to Bridge object.
• More Freya/Loki refactoring.
• Finished refactoring Freya code.
• Started refactoring Freya and Loki code.
• Remove serial input echo so ROS Arduino Bridge functions properly. Added option to invert encoder sense but have left it to be functionally as it was before so it is a debug compile time option.
• Lot's of code refactoring.
• Got bus_server to talk to bus_bridge_encoders_sonar on the bus.
• Converted code into Bus_Server class. Added in some serial port code from the Configurator project.
• Got bus_server_server to respond to messages from bus_bridge_encoders_sonar .
• Added missing Frame_Buffer.cpp/h
• Refactored sharable code from bus_raspberry_pi.
• Added BusInt{8,16,32}{Get,Set}.srv RCP messages.
• Initial commit.
• Contributors: Mark, Rohan Agrawal, Wayne C. Gramlich, Wayne Gramlich