#include <vpForceTorqueIitSensor.h>

Public Member Functions
	vpForceTorqueIitSensor ()

	~vpForceTorqueIitSensor ()

void	bias ()

bool	connected (int timeout_ms=0) const

vpColVector	getForceTorque (bool filtered=false)

void	startStreaming ()

void	stopStreaming ()

Protected Member Functions
void	acquisitionLoop ()

void	close ()

void	join ()

Protected Attributes
ftSensorLib	m_ftLib

int	m_numSensorsInLib

vpColVector	m_ft

vpColVector	m_ft_filt

ftSensorsConnected	m_ftSensorsData {}

std::atomic< bool >	m_acquisitionEnabled

std::atomic< bool >	m_dataValid

bool	m_connected

std::thread	m_acquisitionThread

std::chrono::time_point< std::chrono::system_clock >	m_timeCur

std::chrono::time_point< std::chrono::system_clock >	m_timePrev

std::mutex	m_mutex

int	m_warmupMilliseconds

Detailed Description

This class is a wrapper over six axis load measurement (forces and torques) from IIT (ISTITUTO ITALIANO DI TECNOLOGIA) sell by Alberobotics.

The following example shows how to use this class to stream force-torque data at 1kHz and print a measurement each second.

#include <iostream>
#include <visp3/core/vpTime.h>
#include <visp3/sensor/vpForceTorqueIitSensor.h>
int main()
{
#ifdef VISP_HAVE_FT_IIT_SDK
  vpForceTorqueIitSensor iit_ft;
  if ( ! iit_ft.connected() ) {
    std::cout << "Unable to connect to IIT force-torque sensor" << std::endl;
    return EXIT_SUCCESS;
  }
  iit_ft.bias();
  iit_ft.startStreaming();
  vpColVector ft;
  for(int i=0; i < 10; i++) {
    ft = iit_ft.getForceTorque();
    std::cout << ft.t() << std::endl;
    vpTime::sleepMs(1000);
  }
  iit_ft.stopStreaming();
#else
  std::cout << "ViSP is not build with IIT force-torque SDK support" << std::endl;
#endif
  return EXIT_SUCCESS;
}

Once build, in the same folder as the binary you should find a configuration file named configurationSettings.ini.

Such a file is provided in $VISP_WS/modules/sensor/test/force-torque/configurationSettings.ini with default settings.
; Configuration Settings for FT Sensor LIB
[GENERAL] ; General Settings
NUM_SENSORS = 1 ; Number of Connected FT Sensors
MULTI_SENSOR_MODE = false ; Multi Sensor Mode: if "true", the library
; will use the BASE_SETTINGS in order to
; initialize the communication with the number of
; sensors (NUM_SENSORS) it is initialized with.
; If "false", then the library will check
; the "USE_DEFAULT_SETTINGS".
USE_DEFAULT_SETTINGS = true ; If "true", the library will use the
; DEFAULT_SETTINGS. Note that the sensor
; needs to be in the "DEF" IP position.
; If "false", the library will use the
; USER_SETTINGS to initialize the communication
; with the sensor.
BROADCAST_POLICY = 255 ; Sensor Broadcast Policy: 255
BROADCAST_RATE = 2 ; Sensor Broadcast Rate: represents number of multiples of 0.5 msec,
; with minimum value of 2 e.g. 2*0.5 = 1 msec
LOCAL_IFACE_IP = 192.168.1.100 ; Host Computer's local interface IP
LOCAL_PORT = 2000 ; Host Computer's local interface IP
LOCAL_IFACE = enp0s20f0u1u3 ; Host Computer's local interface name (it is required only in Linux)
[DEFAULT_SETTINGS] ; DEFAULT SETTINGS FOR USE IN SINGLE_SENSOR_MODE when USE_DEFAULT_SETTINGS=true
DEFAULT_IP = 192.168.1.1 ; Default Sensor IP
DEFAULT_PORT = 23 ; Default UDP Port
[USER_SETTINGS] ; USER SETTINGS FOR USE IN SINGLE_SENSOR_MODE when USE_DEFAULT_SETTINGS=false
USER_IP = 192.168.1.1 ; User Sensor IP
USER_PORT = 2000 ; User UDP Port
[BASE_SETTINGS] ; BASE SETTINGS FOR USE IN MULTI_SENSOR_MODE when MULTI_SENSOR_MODE=true
BASE_IP = 169.254.89.20 ; Base Sensor IP
BASE_PORT = 22 ; Base UDP Port
BASE_FIRST_BOARD_NUMBER = 1 ; Base First Sensor Board Number. range 1-9
To modify default settings you need first to identify your Ethernet link:
$ ifconfig
enp0s31f6: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.100.100 netmask 255.255.255.0 broadcast 192.168.100.255

and then modify accordingly the following lines:

LOCAL_IFACE_IP = 192.168.100.100       ; Host Computer's local interface IP
LOCAL_IFACE = enp0s31f6                ; Host Computer's local interface name (it is required only in Linux)

The sensor default IP is set to 192.168.1.1. Browsing to this address with Firefox allows to modify it's default IP address. If the new sensor IP address is for example 192.168.100.10, you need to modify the following line:

USE_DEFAULT_SETTINGS = false           ; If "true", the library will use the
                                       ; DEFAULT_SETTINGS. Note that the sensor
                                       ; needs to be in the "DEF" IP position.
                                       ; If "false", the library will use the
                                       ; USER_SETTINGS to initialize the communication
                                       ; with the sensor.
[USER_SETTINGS]                        ; USER SETTINGS FOR USE IN SINGLE_SENSOR_MODE when USE_DEFAULT_SETTINGS=false
USER_IP = 192.168.100.10               ; User Sensor IP

When running a binary that uses vpForceTorqueIitSensor class,

if you experience the following error:
$ cd $VISP_WS/modules/sensor
$ ./testForceTorqueIitSensor-simple
./testForceTorqueIitSensor-simple: error while loading shared libraries: libftSensorLib.so.0.0.1: cannot open shared
object file: No such file or directory
it means that you need to add the location of the library in LD_LIBRARY_PATH environment variable. This could be achieved running:
$ export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$VISP_WS/3rdparty/FT_SDK_01_4/linux/ubuntu16.04/ftSensorLibReleaseExamples/library/bin/lin-x86_64/release
where $VISP_WS/3rdparty/FT_SDK_01_4 contains IIT SDK.

To configure the sensor, you may access the sensor through the web interface using uour favorite browser.

Examples:: testForceTorqueIitSensor.cpp.

Definition at line 146 of file vpForceTorqueIitSensor.h.

Constructor & Destructor Documentation

vpForceTorqueIitSensor::vpForceTorqueIitSensor ( )

Default constructor.

Establish communication with sensor(-s) and start data acquisition thread.

Definition at line 54 of file vpForceTorqueIitSensor.cpp.

References m_connected, m_ftLib, and m_numSensorsInLib.

vpForceTorqueIitSensor::~vpForceTorqueIitSensor ( )

Destructor that stops streaming

Definition at line 93 of file vpForceTorqueIitSensor.cpp.

References close().

Member Function Documentation

void vpForceTorqueIitSensor::acquisitionLoop ( )

protected

Acquisition loop. Warm up the sensor

Definition at line 108 of file vpForceTorqueIitSensor.cpp.

References m_acquisitionEnabled, m_dataValid, m_ft, m_ft_filt, m_ftLib, m_ftSensorsData, m_mutex, m_timeCur, m_timePrev, and m_warmupMilliseconds.

Referenced by startStreaming().

void vpForceTorqueIitSensor::bias ( )

Bias all sensors by TCP.

Examples:: testForceTorqueIitSensor.cpp.

Definition at line 159 of file vpForceTorqueIitSensor.cpp.

References m_ftLib.

void vpForceTorqueIitSensor::close ( )

protected

Stops data streaming.

Definition at line 83 of file vpForceTorqueIitSensor.cpp.

References m_acquisitionEnabled, m_dataValid, and m_ftLib.

Referenced by ~vpForceTorqueIitSensor().

bool vpForceTorqueIitSensor::connected ( int timeout_ms = 0 ) const

Return true if communication established with at least one sensor.

Parameters

timeout_ms : Timeout in milliseconds.

If you get the following error:

[ ERROR: ] Connection failed! Error Connection refused

it means probably that you didn't set the right parameters in the configuration file configurationSettings.ini. See class description to get some hints.

Examples:: testForceTorqueIitSensor.cpp.

Definition at line 172 of file vpForceTorqueIitSensor.cpp.

References vpChrono::getDurationMs(), m_connected, vpTime::sleepMs(), and vpChrono::start().

vpColVector vpForceTorqueIitSensor::getForceTorque ( bool filtered = false )

Get force-torque data in SI units.

Parameters

[in]

filtered

: When true return filtered force-torque measurements, when false return raw data. If no filter is configured while getting filtered measurements, the SDK will retun the raw data. To configure the filter, you must access the sensor through the web interface. The default ip address is 192.168.1.1 if in default mode. Once in the web interface select NETWORK SETTINGS and you can configure the Data Filtering Settings:

Filter Type: Low-Pass or High-Pass Butterworth
Filter Order: 1, 2 or 3
Cut-off Frequency: frequency in Hz

Returns: A 6-dim vector $[F_x \; F_y \; F_z \; T_x \; T_y \; T_z]^T$ with forces , , in N, and torques , , in Nm.

As shown in the next image, our sensor has IP 192.168.100.10. Filtering is configured as Low-Pass, with a 3 order filter and a 10 Hz cutt-off frequency.