How to force Ubuntu to give the same name to the usb devices (ttyUSB)

Fixing the USB2Dynamixel ttyUSB names problem

http://unix.stackexchange.com/a/183492
http://rolfblijleven.blogspot.co.uk/2015/02/howto-persistent-device-names-on.html

$ dmesg | grep ttyUSB 
[ 1173.771734] usb 2-1: FTDI USB Serial Device converter now attached to ttyUSB0

$ udevadm info --name=/dev/ttyUSBx --attribute-walk
Udevadm info starts with the device specified by the devpath and then
walks up the chain of parent devices. It prints for every device
found, all possible attributes in the udev rules key format.
A rule to match, can be composed by the attributes of the device
and the attributes from one single parent device.

  looking at device '/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1:1.0/ttyUSB0/tty/ttyUSB0':
    KERNEL=="ttyUSB0"
    SUBSYSTEM=="tty"
    DRIVER==""

  looking at parent device '/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1:1.0/ttyUSB0':
    KERNELS=="ttyUSB0"
    SUBSYSTEMS=="usb-serial"
    DRIVERS=="ftdi_sio"
    ATTRS{port_number}=="0"
    ATTRS{latency_timer}=="1"

  looking at parent device '/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1:1.0':
    KERNELS=="2-1:1.0"
    SUBSYSTEMS=="usb"
    DRIVERS=="ftdi_sio"
    ATTRS{bInterfaceClass}=="ff"
    ATTRS{bInterfaceSubClass}=="ff"
    ATTRS{bInterfaceProtocol}=="ff"
    ATTRS{bNumEndpoints}=="02"
    ATTRS{authorized}=="1"
    ATTRS{supports_autosuspend}=="1"
    ATTRS{bAlternateSetting}==" 0"
    ATTRS{bInterfaceNumber}=="00"
    ATTRS{interface}=="FT232R USB UART"

  looking at parent device '/devices/pci0000:00/0000:00:1d.0/usb2/2-1':
    KERNELS=="2-1"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceProtocol}=="00"
    ATTRS{devpath}=="1"
    ATTRS{idVendor}=="0403"
    ATTRS{speed}=="12"
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bMaxPacketSize0}=="8"
    ATTRS{busnum}=="2"
    ATTRS{devnum}=="2"
    ATTRS{configuration}==""
    ATTRS{bMaxPower}=="90mA"
    ATTRS{authorized}=="1"
    ATTRS{bmAttributes}=="80"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{maxchild}=="0"
    ATTRS{bcdDevice}=="0600"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{quirks}=="0x0"
    ATTRS{serial}=="AI0284F3"
    ATTRS{version}==" 2.00"
    ATTRS{urbnum}=="16"
    ATTRS{ltm_capable}=="no"
    ATTRS{manufacturer}=="FTDI"
    ATTRS{removable}=="unknown"
    ATTRS{idProduct}=="6001"
    ATTRS{bDeviceClass}=="00"
    ATTRS{product}=="FT232R USB UART"

  looking at parent device '/devices/pci0000:00/0000:00:1d.0/usb2':
    KERNELS=="usb2"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceProtocol}=="00"
    ATTRS{devpath}=="0"
    ATTRS{idVendor}=="1d6b"
    ATTRS{speed}=="12"
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{authorized_default}=="1"
    ATTRS{busnum}=="2"
    ATTRS{devnum}=="1"
    ATTRS{configuration}==""
    ATTRS{bMaxPower}=="0mA"
    ATTRS{authorized}=="1"
    ATTRS{bmAttributes}=="e0"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{maxchild}=="2"
    ATTRS{interface_authorized_default}=="1"
    ATTRS{bcdDevice}=="0404"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{quirks}=="0x0"
    ATTRS{serial}=="0000:00:1d.0"
    ATTRS{version}==" 1.10"
    ATTRS{urbnum}=="29"
    ATTRS{ltm_capable}=="no"
    ATTRS{manufacturer}=="Linux 4.4.0-62-generic uhci_hcd"
    ATTRS{removable}=="unknown"
    ATTRS{idProduct}=="0001"
    ATTRS{bDeviceClass}=="09"
    ATTRS{product}=="UHCI Host Controller"

  looking at parent device '/devices/pci0000:00/0000:00:1d.0':
    KERNELS=="0000:00:1d.0"
    SUBSYSTEMS=="pci"
    DRIVERS=="uhci_hcd"
    ATTRS{irq}=="18"
    ATTRS{subsystem_vendor}=="0x1ab8"
    ATTRS{broken_parity_status}=="0"
    ATTRS{class}=="0x0c0300"
    ATTRS{driver_override}=="(null)"
    ATTRS{consistent_dma_mask_bits}=="32"
    ATTRS{dma_mask_bits}=="32"
    ATTRS{local_cpus}=="00000003"
    ATTRS{device}=="0x2658"
    ATTRS{enable}=="1"
    ATTRS{msi_bus}=="1"
    ATTRS{local_cpulist}=="0-1"
    ATTRS{vendor}=="0x8086"
    ATTRS{subsystem_device}=="0x0400"
    ATTRS{numa_node}=="-1"
    ATTRS{d3cold_allowed}=="0"

  looking at parent device '/devices/pci0000:00':
    KERNELS=="pci0000:00"
    SUBSYSTEMS==""
    DRIVERS==""
    
$ sudo nano /etc/udev/rules.d/99-usb-serial.rules
SUBSYSTEM=="tty", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001", ATTRS{serial}=="AI0284F3", SYMLINK+="USB2Dynamixel01"

$ sudo udevadm control --reload-rules
$ sudo udevadm trigger
or 
$ /etc/init.d/udev stop
$ udevadm control --reload-rules
$ /etc/init.d/udev start


Another possible solution is to find a unique name with the command below:
$ ls -la /dev/serial/by-id

Then, after all that, add the current user to the dialout group:
(http://askubuntu.com/questions/133235/how-do-i-allow-non-root-access-to-ttyusb0-on-12-04)
$ sudo usermod -a -G dialout $USER

When using the /dev/serial/by-id you MUST pass the whole thing inside your launch file:
port_name: '/dev/serial/by-id/your-fancy-unique-name'