Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J13/00—Controls for manipulators
  • B25J13/08—Controls for manipulators by means of sensing devices, e.g. viewing or touching devices
  • B25J13/081—Touching devices, e.g. pressure-sensitive
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J19/00—Accessories fitted to manipulators, e.g. for monitoring, for viewing; Safety devices combined with or specially adapted for use in connection with manipulators
  • B25J19/0091—Shock absorbers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J19/00—Accessories fitted to manipulators, e.g. for monitoring, for viewing; Safety devices combined with or specially adapted for use in connection with manipulators
  • B25J19/06—Safety devices
  • B25J19/063—Safety devices working only upon contact with an outside object

Definitions

• the present invention relates to an impact detection system for a robotic device.
• the invention also relates to a robotic device equipped with at least one such detection system.
• This robot can, in fact, by making a movement, for example a rotation of an arm, to strike an operator in the field of movement of this arm.
• a movement for example a rotation of an arm
• the operator who is thus touched can be injured if the shock is sufficiently violent.
• Sensitive skins based on matrix distributions of sensory sensors capable of detecting a contact are also known.
• tactile surfaces comprising two conductive or resistive materials for detecting a contact by electrical resistivity measurements.
• the present invention aims at overcoming these various disadvantages of the prior art by proposing an impact detection system for a robot that is simple in its design and in its operating mode, which is economical and has a very high sensitivity for measuring impacts of the same type. very low energies.
• Another object of the present invention is such a system allowing the detection of the point of impact reliably and quickly.
• the invention relates to an impact detection system for a robotic device.
• this detection system comprises:
• a flexible covering element for enveloping or covering a portion of said robotic device, said covering element delimiting an interior air volume
• At least one sensor for measuring the differential pressure between the pressure in said interior air volume and the external pressure of said covering element
• a detection unit configured to receive the measurement signal of said at least one sensor, to perform on the basis of said measurement signal an analysis for detecting an abrupt variation of said pressure and to emit a stop signal to said robotic device when such a variation is detected.
• Sudden variation of pressure is understood to mean a high frequency variation of this pressure such as that resulting from the generation of a sound wave propagating in said interior volume following an impact on said covering element.
• the pressure outside said cover member is typically the pressure in the area such as a room or hall, in which the robotic device is placed. This external pressure will therefore generally be atmospheric pressure but not necessarily.
• the thickness of said cover element is preferably less than 15 mm and more preferably 10 mm so as not to limit the movements of said moving part.
• Such an impact detection system advantageously makes it possible to very significantly improve the safety of the robots and thus allow their use near the operators with greater security.
• such a detection system comprising one or more sensors not distributed over the entire skin, such as devices of the state of the art but located on the edges of this skin, fewer sensors are necessary and the wiring of these sensors is easier.
• this system comprises at least two sensors for measuring the differential pressure.
• the implementation of at least two sensors provides the necessary redundancy in case of failure / malfunction of one of the sensors.
• the implementation of three or more sensors that is to say at least three sensors, to determine the position of impact by triangulation.
• said cover member comprises a flexible material permeable to air, said material being covered with a sealed wall on at least one of its faces.
• said covering element comprises two flexible walls assembled on their periphery in a sealed manner delimiting between these two walls an internal volume in which is placed the flexible material.
• the flexible waterproof wall is made of flexible plastic material or rubber.
• said flexible air permeable material is selected from the group consisting of foam, open cell foam, fibrous wadding, elastic component and combinations thereof.
• said covering element is a self-inflating mat
• said detection unit comprises, for each sensor, an electronic circuit comprising an impedance matching stage at the output of which are placed two resistors for separating the signal coming out of this stage of impedance matching in two signals, each signal being sent to a separate input of a comparator, a detector for measuring a signal output of said comparator corresponding to a pressure variation for a time ⁇ .
• the electronic system can alternatively be completely analog: the sensor signal is digitally filtered to obtain the same result.
• this system comprises a security interface intended to be placed between said cover element and said part of the robotic device, said security interface being able to detect a pressure applied on said interface and to send an alarm signal to a control unit said control unit sending a stop signal to said robotic device when it receives such an alarm signal.
• this interface may be made with a sensitive skin comprising in its thickness two spaced apart conductive materials, which transmit a signal when they come into contact under the effect of a shock.
• said at least one sensor is intended to be mounted directly on said robotic device or is deported with respect to said element of covering not to form a hard point on said cover member
• this system comprises a probe for measuring the pressure in said interior volume
• this system comprises an inflation device for maintaining a constant pressure in said interior volume.
• this pressure Pfonctionnism is of the order of 3 to 4 bars to ensure good sensitivity of the detection system impacts.
• the present invention also relates to a robotic assembly comprising a robotic device and a detection system as described above.
• FIG. 1 schematically represents an impact detection system for a robot according to a particular embodiment of the present invention
• FIG. 2 is a schematic view of the detection unit of the system of FIG. 1,
• FIG. 3 shows a skin equipped with two sensors of the system of FIG. 1,
• FIG. 4 shows a robot of which a part of the articulated arm is covered with a skin as shown diagrammatically in FIG. 1.
• FIGS 1 to 3 describe an impact sensing system for a robot according to a particular embodiment of the present invention.
• This robot is here placed in a building at atmospheric pressure Pr a tm
• This system comprises a flexible cover element, or sensitive skin, for covering a part of this robot such as its arm (not shown), which is likely to collide with an object or a person during its movement.
• This covering element 10 is here a self-inflating mat comprising a foam bagged in a sealed plastic envelope.
• This self-inflating mattress 10 defines a volume 1 1 of indoor air with an internal pressure Pr int .
• the covering element 10 being flexible and inflated, it advantageously defines a protective barrier capable of absorbing light impacts.
• this covering member 10 automatically maintaining its shape, it does not require any inflation device and is therefore always operational.
• the system also includes two sensors 12 offset at the ends of the cover member 10 so as not to form a hard point on the outer surface of this element.
• These sensors 12 measure the differential pressure between the pressure Pr int in the volume 1 1 of indoor air defined by the covering element 10 and the atmospheric pressure P r a t m
• a pressure wave 13 traverses the interior of the volume delimited by the self-inflating mattress 10 generating a pressure disturbance which is detected by the two sensors 12.
• a detection unit 13 configured to receive the measurement signals of the two sensors 12, to execute for each signal an analysis to detect a sudden variation of said pressure and to emit a stop signal to the robot when a such variation is detected.
• the detection unit 13 comprises an electronic circuit associated only with this sensor and comprising a first operational amplifier 14 at the output of which two resistors 15, 16, each going on a separate input of a second operational amplifier 17, the values of the resistors 15, 1 6 being identical or as close as possible.
• the inverting input 171 of the second operational amplifier 17 is connected to ground by a capacitor 18, the assembly formed by the resistor 16 and the capacitor 18 forming a low-pass filter on the inverting input 171 of the second operational amplifier 17.
• the capacitor 18 / resistor 1 6 assembly removes all the high frequencies of the signal and passes only the low frequencies.
• Positive input side 172 of the operational amplifier 17 everything passes, including the pressure variations from the impacts on the element 10 covering.
• the second operational amplifier 17 mounted as a comparator gives its output a signal equal to 1 (high level) during a variation of pressure throughout the duration ⁇ of this variation.
• a microcontroller (not shown) then makes it possible to measure the signal at the output of the second operational amplifier.
• This circuit also has a pull-up resistor 20 so that the comparator does not trigger on the noise present on the non-inverting input.
• This circuit advantageously allows the detection of minute pressure variations and has a very high reactivity and a very short rise time.
• this rise time is here of the order of 100 nanoseconds.
• the signals sent to the comparator 17 are not identical because a branch of the electronic circuit has a capacity inducing a delay, and can therefore vary only slowly. In addition, a pull resistance causes the voltage to rise slightly, so that the sensor noise does not generate bad detections.
• the second branch of the electronic circuit varies quickly.
• this detection system allows the determination of the point of impact on the surface of the covering element.
• the detection system works even when it shows slight leaks. It is also observed that the variations in the external pressure of said covering element such as atmospheric pressure, and, for example, linked to meteorological conditions or still resulting from rapidly closing doors, are sufficiently slow and uniform for the detection system to react. not.
• the use of several sensors 1 2 provides redundant detection making the detection system more secure. It also offers the possibility of triangulating the signals sent by the sensors 1 2 in order to estimate the contact position on the surface of the covering element.
• this system comprises three sensors for measuring the differential pressure Ci, C 2 and C 3 and in the case where the sensor Ci is the first to detect a pressure disturbance, the sensor C 2 being the second and the sensor C 3 being the third to detect this disturbance. Then the measurement time differences are respectively (t 2 -ti) and (t 3 -ti).
• the distance separating the point of impact from the position of the sensor Ci is r
• the distances separating the point of impact of the sensors C 2 and C 3 are respectively r + cx (t 2 -ti) and r + cx (t 3 -ti) where c is the speed of propagation of the wave in the interior volume of the cover member.

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• Engineering & Computer Science (AREA)
• Robotics (AREA)
• Mechanical Engineering (AREA)
• Human Computer Interaction (AREA)
• Force Measurement Appropriate To Specific Purposes (AREA)
• Manipulator (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Cites Families (6)

• 2013
  • 2013-12-26 FR FR1363611A patent/FR3016039B1/fr not_active Expired - Fee Related
• 2014
  • 2014-12-23 EP EP14823998.1A patent/EP3086910A1/de not_active Withdrawn
  • 2014-12-23 CN CN201480076246.5A patent/CN106029309B/zh active Active
  • 2014-12-23 US US15/107,665 patent/US20160318188A1/en not_active Abandoned
  • 2014-12-23 WO PCT/EP2014/079146 patent/WO2015097215A1/fr active Application Filing

Non-Patent Citations (1)

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