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From: "Victor B. Naumov" <nau@iias.spb.su>
Subject: Russian Robotics 5/8: 6D Force/Torque Sensor
Message-ID: <MBOYER.95Jul5164656@pellan.ireq-robot.hydro.qc.ca>
Lines: 123
Sender: news@ireq.hydro.qc.ca (Netnews Admin)
Organization: St.-Petersburg Institute for Informatics and Automation, RAN
Date: Wed, 5 Jul 1995 20:46:56 GMT
Approved: mboyer@ireq-robot.hydro.qc.ca, crr@ireq-robot.hydro.qc.ca

                 ACADEMY OF SCIENCES OF RUSSIA
   ST.-PETERSBURG INSTITUTE FOR INFORMATICS AND AUTOMATION
                         ROBOTICS LAB.
                     of prof.F.M.Kulakov



                   6-D Force/Torque Sensor
                   -----------------------


Fields of Application
---------------------

- Robotics:  for measuring of forces and torques during the process of
interaction between the robot and its environment (robotic assembly,
grinding, polishing, automatic measuring of dimensions, etc.).

- Motor-car industry and construction:  for test of shock-absorbers;
for measuring of forces acting on driver and passenger, for control of
active suspension, etc.

- Mining industry:  for measuring of forces acting on the mine lift
and using of this information for control of lift, for measuring of
tension of the lift's rope, etc.

Description of function and handling
-------------------------------------

6-D Force-Torque sensor measures the forces and torques, acting on
different objects.  The mechanical part of the sensor consists of two
flanges which are connected by a special elastic tubular construction.

To measure forces acting on the object, the force/torque sensor must
be connected with the object by one flange and forces must act on the
other flange.  For instance, in case of a robot, one flange is
connected with the gripper, other flange is connected to the arm of
robot.  If forces act on the gripper, they deform the elastic part of
the sensor, and strain gauges, mounted on it, transform deformation of
the sensor into 6 electrical signals.  Three of them are proportionate
to Cartesian projections of applied force.  The other 3 signals are
proportionate to Cartesian projections of applied torque.

The sensor's electronics include special hardware which transform
these signals into a digital form [ADC?  -IS].  Signals are supplied 
in this, digital form.

For instance these signals are used as feedback for a force robot
control system of an assembly robot, for control motion of a mine
lift, or for testing of shock absorbers in order to reject shock
absorbers if its oscillations are not standard.

Hardware
--------

-controller to form digital signals for control, for test of sensor
and other functions

Software
--------

- software for support of sensor and exchange with control systems
of controlled devices

                                 Technical date

--------------------------------------------------------------------
Items and units of                   Specification  values
measurement                     Px     Py      Pz     Mx    My   Mz
--------------------------------------------------------------------

Minimum * force range,  N      0-50    0-50    0-50
          torque range, N*M                          0-2   0-2   0-2

Maximum * force range,  N     0-1000  0-1000  0-1000
          torque range, N*M                          0-30  0-30  0-30

Ultimate load,           %      10      10      10     20    15    15

Sensibility,             mV/N  0,0148  0,0111  0,0113
                       mV/N*N                        0,645 0,444 0,455

Main error,              %        0,2     0,2    0,2   0,3   0,2  0,25

---------------------------------------------------------------------
Working temperature range (C):        -60 -  +70

Power voltage (V):                       15

Number of motion channels:                6

Number of binary digits of data bus:     12

Number of digits of channel address bus:  3

Conversion time (Mk sek):               500
----------------------------------------------------------------------------

* Several sensors are currently in production.  The table presents
data for the smallest and largest sensor.


Advantages
----------

- Interdependency of output signals is completely absent 
- Working temperature range is very large
- Price is less than the prices of similar devices made by other
  firms with comparable or superior performance
- Very short conversion time

Orders on sensors are accepted at any quantity, and they are carried
out by plants of the former Military Industry Complex.


Sensors are used by Scientific Industrial Union "ENERGIJA" and by
other space and industrial firms.


--
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