WO2011120094A1 - Procédé et appareil pour simuler une réponse haptique - Google Patents

Procédé et appareil pour simuler une réponse haptique Download PDF

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Publication number
WO2011120094A1
WO2011120094A1 PCT/AU2011/000370 AU2011000370W WO2011120094A1 WO 2011120094 A1 WO2011120094 A1 WO 2011120094A1 AU 2011000370 W AU2011000370 W AU 2011000370W WO 2011120094 A1 WO2011120094 A1 WO 2011120094A1
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bladder
patient
response
control
tactile feedback
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Olivier Salvado
David Passenger
Fung Ming Mario Cheng
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Commonwealth Scientific and Industrial Research Organization CSIRO
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Commonwealth Scientific and Industrial Research Organization CSIRO
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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09B—EDUCATIONAL OR DEMONSTRATION APPLIANCES; APPLIANCES FOR TEACHING, OR COMMUNICATING WITH, THE BLIND, DEAF OR MUTE; MODELS; PLANETARIA; GLOBES; MAPS; DIAGRAMS
    • G09B23/00—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes
    • G09B23/28—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes for medicine
    • G09B23/285—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes for medicine for injections, endoscopy, bronchoscopy, sigmoidscopy, insertion of contraceptive devices or enemas

Definitions

  • the present invention relates to an apparatus and method for simulating a response to a tactile medical examination of a patient, and, particularly, but not exclusively, to a method and apparatus for simulating a response to a tactile medical examination of a patient's abdomen.
  • colonoscopy and endoscopy may often require haptic examination in order to ensure that the operation proceeds correctly.
  • haptic examination in order to ensure that the operation proceeds correctly.
  • a common and important procedure in colonoscopy involves cooperation between the gastroenterologist and assistants in the application of abdominal palpation. Palpation techniques are used in 15 to 20% of cases to aid the gastroenterologist in
  • Palpations are conducted by an assistant (usually) using the fingers, palm or forearm over identified regions of the abdomen to increase the rigidity of the nearby colon segments, thereby suppressing loop formation and enabling tip (colonoscope tip) navigation past troublesome flexures.
  • an assistant usually using the fingers, palm or forearm over identified regions of the abdomen to increase the rigidity of the nearby colon segments, thereby suppressing loop formation and enabling tip (colonoscope tip) navigation past troublesome flexures.
  • a problem is that novice gastroenterology assistants commonly perform their first abdominal
  • colonoscopy simulators focus generally on solely training the
  • the abdomen is a complex combination of various
  • soft-tissue organs and tissues such as fat, muscle, liver, large and small colon.
  • the make up of these soft tissues and their anatomical layout contributes to the tactile feedback during the palpation and thus are important factors to consider in abdominal simulation.
  • the present invention provides a simulator apparatus for simulating a response to a tactile medical examination of a patient, comprising a first tactile feedback arrangement and a second tactile feedback arrangement, the first and second tactile
  • feedback arrangement being arranged together to provide a response simulating patient surface tactile feedback and a patient body type.
  • the first and second tactile feedback arrangements are arranged to operate together to provide response components giving a total response which
  • the first tactile feedback arrangement is a first fluid operated bladder arranged to provide a variable pressure response to tactile stimulation.
  • the second tactile feedback arrangement comprises a platform body arranged, in operation to support the first fluid operated bladder.
  • the platform body is arranged to vary in height relative to the first fluid operated bladder.
  • the platform body is arranged to control displacement of an interface with the first fluid operated bladder. The height of the interface can be varied. This facilitates simulation of patient body type.
  • the body type may be related to virtual Body Mass Index (BMI) of the simulated patient.
  • BMI Body Mass Index
  • the first fluid operated bladder is constrained with the platform in a preset volume.
  • the preset volume constraint is implemented by an enclosure mounted about the fluid operated bladder and the platform. The enclosure may comprise webbing
  • the second tactile feedback arrangement comprises a second fluid operated bladder.
  • a fuzzy logic control system together with a plurality of valves is used to vary fluid pressure within the first and second bladders.
  • the apparatus further comprises a probe body, arranged to represent a moveable probe within a patient.
  • the probe body may represent a colonoscope, so that a colonoscopy operation can be simulated via the apparatus.
  • the probe may be positioned between the first and second tactile feedback arrangements. Where they are first and second bladders, the probe's motion is determined at the
  • An advantage of such a simulator apparatus is that the simulator is available to enable doctors and their assistants to simulate haptic operations on patients.
  • a further advantage of at least an embodiment of the present invention is that the apparatus is able to be implemented in a mannequin, providing a fully immersive solution, to enable comprehensive training of operators.
  • a plurality of simulator apparatus may be used together to provide a system for representing a part of a patient's body, such as the total abdominal or chest area.
  • a plurality of the apparatus may be used in different locations eg in a mannequin, to represent the "feel" of various parts of the abdomen and/or chest and/or other parts of the body in haptic operations .
  • the ⁇ present invention provides a simulator apparatus for simulating a response to a tactile medical examination of a patient, comprising a first tactile feedback arrangement and a second tactile feedback arrangement, the first tactile feedback
  • a body arranged to provide a tactile response to manipulation of the body by an operative
  • a second tactile feedback arrangement comprising a further body forming an interface with the first tactile feedback arrangement, and being operable to raise or lower the interface to bring the interface into or out of haptic range of the first tactile feedback arrangement .
  • objects may be supported at the
  • the objects may form part of the tactile feedback response provided to the operative.
  • the system further comprises a probe body positioned at the interface.
  • the probe body may represent a simulated colonoscope.
  • the first tactile feedback arrangement body may comprise a fluid operated bladder.
  • the further body may comprise a fluid operated bladder.
  • This aspect of the invention may have any or all of the features of the first aspect of the invention.
  • the present invention provides a simulator apparatus for simulating a response to a tactile medical examination of a patient, comprising a first fluid operated bladder and a second fluid operated bladder, wherein the first fluid operated bladder is positioned, in operation, on top of the second fluid operated bladder.
  • This aspect of the invention may have any or all of the features of the aspects of the invention discussed above.
  • the present invention provides a simulator system, comprising a plurality of stimulator apparatus in accordance with any of the first to third aspects of the invention, positioned with respect to each other to represent a part of a patient's body for simulating a response to a tactile medical examination of the part of the patient's body.
  • the part of the patient's body may be the abdomen. In an embodiment, the portion of the patient's body may be the chest.
  • the system may form part of a mannequin, or may be positioned within a mannequin.
  • the present invention provides a mannequin, representing a patient body, and comprising a system in accordance with the fourth aspect of the invention.
  • the present invention provides a method of simulating a response to a tactile medical examination of a patient, comprising the steps of providing a tactile feedback response, simulating patient surface tactile feedback and a patient body type.
  • Figure 1 is a diagram of a simulator apparatus for
  • Figure 2 is a diagram of a first and second fluid operated bladder of the apparatus of Figure 1;
  • Figure 3 is a diagram of a first bladder of Figure 1, illustrating part of a control arrangement
  • Figure 4 is a schematic diagram illustrating a control arrangement for a single bladder of an apparatus in accordance with an embodiment of the present invention
  • Figure 5 is a flow chart illustrating processing of user interactions with an apparatus in accordance with an embodiment of the present invention.
  • Figure 6 and Figure 7 are diagrams of a first and second bladder arrangement of the apparatus of the embodiment of Figure 1, illustrating an operation of the apparatus;
  • Figure 8 is a diagram illustrating how a system in ' accordance with an embodiment of the present invention may be deployed in a mannequin.
  • Figure 9 is a diagram of the embodiment of Figure 1 showing the arrangement as seen from above.
  • a simulator apparatus in accordance with an embodiment of the invention, generally designated by reference numeral 1, comprises a first tactile feedback arrangement 2 and a second tactile feedback arrangement 3.
  • the simulator apparatus 1 is arranged to simulate a response to a tactile medical examination of a patient.
  • a trainee operative can carry out haptic operations on the first and second tactile feedback arrangements, usually from the top surface 4, and obtain a response which simulates a corresponding haptic operation on a real patient.
  • the response can simulate a patient body type, for example as represented by BMI.
  • BMI body mass index
  • the first feedback arrangement is arranged to simulate a response to a tactile medical examination of a patient.
  • a trainee operative can carry out haptic operations on the first and second tactile feedback arrangements, usually from the top surface 4, and obtain a response which simulates a corresponding haptic operation on a real patient.
  • the response can simulate a patient body type, for example as represented by BMI.
  • the abdomen is a complex combination of various soft tissue organs and tissues. Further,
  • this embodiment of the invention is implemented as a haptic simulator for simulating
  • the apparatus comprises a probe body 5.
  • the probe body 5 in this embodiment represents a colonoscope 5, and can be moved to provide a simulation of the "feel" of a colonoscope when the operative palpates the surface .
  • Each of the first and second feedback arrangements comprises a respective first 6 and second 7 pneumatically operated fluid filled (in this example the fluid is air) bladder.
  • the colonoscope template 5 is interposed at the interface between the first 6 and second 7 bladder.
  • a substantially fixed volume mesh 8 encloses the bladders 6 and 7, in order to control the overall volume.
  • Pressure within the bladders 6 and 7 is controlled by a fuzzy control system 8 controlling a plurality of valves (not shown in Figure 1 , to be described later) for sourcing and exhausting air to/from the bladders 6 and 7.
  • the fuzzy control system 8 as illustrated in Figure 1 , comprises a first fuzzy logic controller 9, responsible for control of pressure in the first bladder 6 and a second fuzzy logic controller 10 responsible for control of pressure in the second bladder 7. Fuzzy logic
  • controller 9 and fuzzy logic controller 10 are connected in turn via a USB port to a computing device such as a PC (not shown) .
  • the fuzzy control system is coupled with a pulse width modulation scheme to maintain the
  • the forces felt at the operative's hand (fingers or palm) .
  • the amount of force applied depends greatly on different body types, primarily the abdominal fat and muscle content.
  • the body type will determine if the operative can feel the colonoscope during the application of abdominal pressure. As such, the direction and amount of pressure is applied on a trial and error basis to regulate paradoxical motion (of the colonoscope) .
  • the first (surface) bladder 6 is used to simulate the forces during abdominal palpation as experienced by the palm of the operative's hand or
  • the second (displacement) bladder 7 is used to control the height of the colonoscope template 5, as measured from the base of the apparatus.
  • the colon may be unobstructed to fat and muscular tissue (such as elderly women, for example) . That is, there is a relatively low BMI . Whilst in obese patients the converse may be true and it may not be possible to feel the colonoscope.
  • the colonoscope height can therefore be predetermined and set for the simulation, via the
  • dynamic height control during interaction by varying the pressure in the displacement bladder 7 may also be implemented.
  • FIG. 3 is a diagram of the surface bladder 6 showing the arrangement in more detail.
  • a PWM (Pulse Width Modulated) signal controls source and exhaust via intake valves 15 and 16.
  • Pressure sensors 17 are able to sense pressure within the bladder 6.
  • the fuzzy logic is used to control a specific bladder property in response to a user determined variable eg pressure or displacement. Fuzzy control operation details are documented in a paper "Pneumatic Haptic Interface Fuzzy Controller for Simulation of Abdominal Palpations During Colonoscopy" proceedings of the third joint
  • Single Bladder Control System Single Bladder Control System
  • FIG. 4 A more detailed diagram of the control system for a single bladder, in this case the surface bladder 6, is shown in Figure 4.
  • Four pressure sensors 17 are distributed within the bladder.
  • Pneumatic actuators are used in the form of fast switching solenoid valves from Matrix. They have fast operating speed and low cost relative to proportional controllers.
  • Solenoid valves (model 820NC2/2) were used with a speed up circuit achieving an on/off frequency of 500 hertz.
  • One solenoid valve 15 is connected to the bladder and supply pressure and used to modulate the inflation rate (valve 15) .
  • the other solenoid valve is used to modulate the deflation rate (valve 16) .
  • PWM is implemented as a modified pressurized linear modulation scheme as described in the paper by Van Varseveld et al (R.van Varseveld and G. Bone. ⁇ Accurate position control of a pneumatic actuator using on/off solenoid valves" .
  • Van Varseveld et al Van Varseveld and G. Bone. ⁇ Accurate position control of a pneumatic actuator using on/off solenoid valves
  • the bladders may be of any convenient material, but in this embodiment, the bladders 6 and 7 are of rubber in order to allow the operative to interact in natural manner akin to the feel and flexibility of human tissue during palpation.
  • the bladders are 9cm by 11cm two-valve sphyganometer bladders.
  • the two bladder control systems of this embodiment of the present invention is illustrated in Figure 1. Two control systems such as illustrated in Figure 4 may be utilized.
  • the displacement bladder 7 is arranged to bring the colonoscope template 5 into interaction range when necessary (static implementation) or appropriate (dynamic implementation using simulation models) .
  • the height of the bladder is controlled by a similar fuzzy control system to the surface bladder, using the bladder height as the fuzzy control variable.
  • the simulation software and physical modelling will determine the patient property for simulation and the desired pressure feedback and height of colonoscope will be calculated and simulated by the haptic device.
  • the use of the multi-bladder haptic device is created to simulate the tactile simulation of abdominal palpations for varying body types experienced in every day
  • the fuzzy control system will treat the user interaction as a disturbance and attempt to correct to retain the target pressure.
  • the changes in palpation depth will be communicated to the PC over the USB connection where a new target pressure will be calculated.
  • the fuzzy control system will correspondingly control the pressure to the target pressure, thereby simulating the tactile feedback for the compression of abdominal tissue.
  • the user interaction will also lead to a change in
  • the fuzzy logic control responsible will increase in the lower bladder pressure to maintain the height of the colonoscope template.
  • the two separate fuzzy logic controllers maintain the balance of forces, which will drive the simulation from initial to full palpation depth; the depth at which the interaction point contacts the bottom of the bladder and the underlying colonoscope template .
  • the lower bladder is depressurised to maintain a low displacement allowing a large amount of palpation depth in the surface bladder ( Figure 7) .
  • this simulation it may be desirable to limit or even prevent the operative's palpation from interacting with the colonoscope. This is accomplished by rapidly increasing the surface bladder pressure once the maximum palpation depth, as determined by PC driven simulation, is reached.
  • the palpation depth and depth of the colonoscope template will depend on the virtual patient which is being simulated on the host PC.
  • the displacement bladder 7 is a dynamic system, which will react to target distance as determined by simulation models on the PC.
  • the virtual patient is likely to have a static target distance per region.
  • the dynamics as described above is a simple interaction between the surface and underlying bladder with minimal sharing of information between the two fuzzy control systems.
  • the hardware control is designed to accommodate more intelligent control systems involving more complex dynamics, which will take full advantage of the bladder dynamics .
  • Figure 9 shows a view of the bladder arrangement from the top.
  • the colonoscope template 5 is shown in a bent configuration (in ghost outline) .
  • the above embodiment shows a single apparatus which may provide haptic feedback.
  • a plurality of such apparatus may be used
  • Figure 8 illustrates an embodiment of the invention which uses a plurality of the apparatus of Figure 1, within a mannequin.
  • Each of the apparatus are designated by reference numeral 1 in Figure 8, to indicate that they are the same type of apparatus.
  • a flexible sensor skin is envisaged for the surface of the mannequin to determine the site of user interaction and used as input to simulation models. Position information can then be added to the haptic response to provide further detail for the simulation.
  • the apparatus of the present invention could be utilised to represent other parts of the body, eg chest, leg, etc where it is necessary to simulate a palpation operation.
  • One, two or more of the apparatus may be used to provide the appropriate "virtual" body layout.
  • a dual -bladder system is
  • a multiple bladder system of three or more bladders that are used together in an apparatus, may provide the appropriate haptic response.
  • one pneumatic bladder may be used as the surface bladder, and in order to provide displacement for the colonoscope, a platform (ie not a bladder) that can be raised or lowered may be used instead of a bladder.
  • the bladders are pneumatic (air operated) bladders.
  • the invention is not limited to pneumatic operated bladders. Any fluid may be utilised if it gives the right haptic response.
  • a liquid filled bladder may be used eg hydro.
  • gases may be used than air if they provide the appropriate response.
  • two bladders are controlled by separate fuzzy logic systems.
  • the invention is not limited to this.
  • the control system may share information from the feedback systems.
  • the bladders are on top of each other.
  • the invention is not limited to this. In other embodiments, it may be appropriate to have bladders side by side providing different response characteristics, for example, or in other spatial arrangements with respect to each other.
  • the application is for a human patient.
  • the invention is not limited to this,
  • application may simulate haptic operations in animal patients .
  • the apparatus has a probe body positioned between the bladders. This simulates a colonoscope operation.
  • the present invention is not limited to simulating a colonoscope operation.
  • Other probes eg endoscope
  • an object representing a tumour or other condition may be provided at the interface.
  • Body Mass Index is one indicator only of varying body type.
  • the invention is not limited to operating based on BMI, but may include other factors or alternative factors in the simulation for providing an appropriate haptic response.
  • Embodiments of this invention may be used in any haptic training, including abdominal palpation, midwifery and others .
  • KEYWORDS Tactile devices and display, Human-computer interaction, Dynamic systems and control.
  • Colonoscopy simulators have been used increasingly in colonoscopy training to reduce training time, financial and opportunity costs . Simulators can provide procedure specific metrics, repeatability of different cases, and decreased cost for colonoscopy training. Furthermore, they may facilitate gastroenterology curricula by providing a more systematic and documented approach.
  • a common and important procedure involving cooperation between the gastroenterologist and assistants is the application of abdominal palpation during colonoscopy intervention. This is done by one of the assistants to aid navigation past certain flexures by applying hand pressure at specific locations on the abdomen.
  • all commercially available simulators aim at training the gastroenterologist alone rather than a simulation environment for the entire colonoscopy team. Palpation techniques are used in 15-20% of cases to aid the gastroenterologist in navigating the colonoscope [8] .
  • a haptic device used to simulate such procedures would be highly desirable as it would improve intra-team
  • colonoscope loops and patient anatomy might impede insertion.
  • the gastroenterologist identifies the likely location of the impedance and asks for an abdominal palpation to be performed by one assistant.
  • the gastroenterologist identifies the likely location of the impedance and asks for an abdominal palpation to be performed by one assistant.
  • Prechel et al [8] described four main palpation areas ( Figure la) ; the sigmoid lift, the sigmoid/ transverse colon, the sigmoid hepatic flexure, and the cecal lift.
  • Figure lb An example of the sigmoid/transverse palpation technique is shown in Figure lb. Pneumatic actuators have been used instead of
  • Figure 1 (a) Abdominal pressure is applied in these four regions to aid navigation of the colonoscope;
  • pneumatic system have a number of
  • Pneumatic air muscles have also been used in robotic arms where solenoid valves controlled armatures up to 30° with a setting time less than 0.3ms with limited oscillation during steady-state [12] .
  • Some researchers reported good steady-state control accuracy using low cost on/off solenoid valves [13, 6], but they have been seldom used for pneumatic control as they introduced non-linearities from limited solenoid flow rates, low valve response time, and high noise levels due to rapid PWM.
  • PID proportional-integral-derivative
  • Fuzzy control largely followed one of two methodologies.
  • fuzzy control served as a supervisory system on top of an existing controller to adjust the gain of coefficients based on inputs [3] .
  • Gao et al described a Fuzzy-PD controller with settling times ranging from 0.5 to 1 second to regulate piston position with a stroke in the range of 20mm-800mm [3] .
  • the relatively slow dynamic response of these systems was attributed to the fuzzy gain control not accounting for the pneumatics non-linearities.
  • fuzzy control has also been implemented as part of a negative feedback loop instead of a linear PID controller [6, 14] .
  • Hybrid controllers have been
  • Parnichkun et al [6] used fuzzy control on a macro level and employed PID for improved accuracy which had a slightly faster performance than a traditional PID approach.
  • Ying et al [14] used fuzzy control for fine regulation whereas a bang-bang controller regulated large displacements. However, they reported oscillation in both step and sinusoidal responses despite a fast settling time of 20ms.
  • Shih et al . [10] proposed an all fuzzy approach to control the position of a pneumatic cylinder with an error of less then 0.1mm under loaded or no load conditions with a settling time of 0.5s despite relatively older solenoid valve technology.
  • fuzzy control systems have been able to account for pneumatic non-linearities with low steady- state error and good dynamic response.
  • FIG. 2 Hardware Diagram of Pneumatic haptic System The hardware design of the pneumatic haptic device is shown in Figure 2.
  • gastroenterology assistant interacts with the patient by placing his/her hands on the abdomen and gradually applies force to gently move the colon and colonoscope.
  • force feedback is initially minimal due to the subcutaneous fat and the initial elasticity of skin. But as the palpation depth increases, the resistance felt by the assistant increases as organs and muscle tissues are compressed. Other environmental factors, such as the presence of the colonoscope in the palpation area, or the respiration might also influence the resistive force. To simulate this behaviour, a 9cm by 11cm two-valve
  • sphyganometer bladder was used to convert pneumatic pressure into resistive force feedback.
  • the rubberised bladder originally used for blood pressure measurements, allowed the chamber to simulate the feel and flexibility of human tissue during palpation illustrated in Figure lb.
  • a photograph of the air bladder is shown in Figure 3.
  • Figure 3 9cm by 11cm 2 valve sphyganometer bladder
  • the rubberised surface of the sphyganometer could resist to stretching or distension up to 5kPa of pressure. Large distension would cause an unnatural lump on the mannequin surface and detract from realism.
  • the change in volume could cause a decrease in pressure within the bladder and thus would decrease the responsiveness of control.
  • the air bladder was placed into a cloth mesh pre-empting large unnatural distensions.
  • the pneumatic actuators used were fast-switching solenoid valves from Matrix [2] . They were chosen for their fast operating speed and low cost relative to proportional controllers.
  • Solenoid valves (model 820 NC 2/2) were used with a speed up circuit achieving an on/off frequency of 500Hz.
  • One solenoid valve was connected to the bladder and supply pressure and used to modulate the inflation flow rate (valve A) .
  • the other solenoid valve was used to modulate the deflation rate (valve B) .
  • Sensors were attached after each valve and used as inputs to the feedback control loop.
  • Freescale MPXV501OG integrated pressure sensors were used to cover the 0-lOkPa range while MPX5050G sensors were used to cover the
  • the purpose of the air bladder was to provide force feedback to the user by controlling the pneumatic pressure within the bladder. As the user interacted with the bladder, the resistive force F was sent a reference force to the controller, which converted it to a pressure reference. We assumed that:
  • PWM converted the controller output command, u, ranging from -100% (full deflation) to 100% (full inflation) , and was converted to duty cycle values for both valve A and B to regulate the flow rate.
  • u 0 when valves A and B were closed [13] .
  • This control scheme however introduced a deadband in the flow rate in cases where u was almost zero. This was due to the valves being activated with a duty cycle shorter than the time required to open and close the solenoids. We designed a system to avoid deadband as it could result in steady-state error, overshoots and oscillation in pressure control.
  • Van Varseveld et al [13] suggested several PWM conversion alternatives to overcome the deadband and linearise flow rate relative to control output.
  • This scheme is illustrated in Figure 4 where the conversion scheme for valve A and B is depicted in dotted line and solid line, respectively.
  • FIG. 4 Pressurised Linear PWM (in solid and dotted Line) and the modified control scheme (solid and dashed line)
  • the altered control scheme for Valve A is shown as a dashed line in Figure 4.
  • control scheme was modified to be pressure dependant by adjusting the duty cycle of valve A relative to the measured bladder
  • valve A which would generate a zero net flow rate was recorded for chamber pressure between 0-8kPa, at multiple 0.5kPa increment. This data was used to generate the control surface illustrated in Figure 5. Given the current chamber pressure, the valve A duty cycle could be interpolated for any value of u.
  • Figure 6 Flow rate over different chamber pressure.
  • the surface shows the valve duty cycle for valve A for any given u or chamber pressure.
  • Control scheme for valve B is shown in grey and is not pressure-variant.
  • Fuzzy control is a simple control method which allows for quick development of non- linear control without the need for a comprehensive mathematical description. It comprises of 3 main
  • fuzzification inference a knowledge base for determining output membership and defuzzification process to resolve output memberships to a scalar control output.
  • Asymmetric triangular fuzzy sets were used to describe the linguistic variables: eleven for the fuzzification of e(t), seven for Ae(t), and eleven for the Q(t).
  • the linguistic labels used to describe the fuzzy sets were (N) negative, (NB) negative big, (NM) negative medium, (NS) negative small, ( V) negative very small, (Z) zero. Similarly, linguistic labels with P prefix were positive.
  • the knowledge base consisted of 77 rules and is presented in a rule matrix as shown in Table 1.
  • the output linguistic variable Q(t) was applied over the control response range -100% (full deflation) to 100% (full inflation) flow rate. Fuzzy sets N and P were saturated to 100 to translate control output at maximum activation.
  • the output membership distribution ( Figure 8) was heavily weighted for the negative output due to the large difference in exhaust and supply flow rates. The output distribution values were tuned to minimise oscillation and overshoot, whilst providing fast dynamic response for eft and Ae(t) values fuzzy sets.
  • Defuzzification used the centre of gravity method (COG) on the output fuzzy set to determine the control response u.
  • u represented the mean of the active fuzzy set resulting from the rules matrix
  • A(Q) was the area determined by Mamdani interface
  • u was the input to the PWM control scheme as outlined in Section 4 to determine the duty cycle for each valve.
  • Figure 9 shows the haptic device undergoing a set of step inputs illustrating the steady state response.
  • the set-points were set at 39N and 85N which represented a small to medium palpation exerted on the bladder.
  • the fuzzy controller control output approached 100% between 80-94% of the settling time, and rapidly decreased for small error.
  • Positive step responses showed an average settling time of 0.43s.
  • the negative step response from 85N to 39N had an average settling time of 0.52s.
  • Figure 9 Step response of the haptic device over 6 seconds .
  • the control output u is shown below the main graph.
  • the sinusoidal test used a sine wave ranging from 0.5Hz to 1.25 Hz, (0.25Hz increments) with amplitude of 45N.
  • the first 6s showed the system responding to a 0.5Hz wave, following 4 s at 0.75Hz.
  • the next 2s show lHz and lastly 1.25Hz.
  • the range was selected to include conservatively the fastest dynamic expected to occur during actual palpations.
  • Figure 10 showed some lag during deflation but fast and accurate response for inflation at all
  • Figure 10 Sinusoidal inputs from 0.5Hz to 1 .25Hz with 0.25 increments over 15 seconds with control output u below.
  • the fuzzy controller we presented was compensating very well for most non-linearities in the system and provided accurate and fast force control for frequencies below 0.5Hz and for positive reference forces of at least
  • Figure 11 Using force data gathered from palpations over a 25 second interaction with control output u below.
  • the haptic device was able to control the resistive forces generated by the air bladder to simulate forces likely to be experienced during abdominal
  • the deflation flow rate was an anticipated non-linearity which affected the dynamic response for high frequency inputs.
  • the fuzzy control performed admirably showing very low steady-state error and high dynamic performance. In situations which did not involve rapid deflation it was able to track, simulate and trace the reference input force.
  • Fuzzy-PD controller for pneumatic servo system Fuzzy-PD controller for pneumatic servo system.

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Abstract

La présente invention concerne un appareil de simulation permettant de simuler une réponse qui se produirait dans le cadre d'un examen médical tactile effectué sur un patient. On utilise des premier et second ballons, positionnés l'un au-dessus de l'autre en cours d'utilisation, pour réaliser respectivement des premier et second agencements de retour d'informations tactile. Les ballons sont commandés pour simuler un retour d'informations tactile de surface du patient, afin de faciliter la formation du personnel médical.
PCT/AU2011/000370 2010-03-31 2011-03-31 Procédé et appareil pour simuler une réponse haptique Ceased WO2011120094A1 (fr)

Applications Claiming Priority (4)

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AU2010901344 2010-03-31
AU2010901344A AU2010901344A0 (en) 2010-03-31 A method and apparatus for simulating a haptic response
AU2010903396 2010-07-29
AU2010903396A AU2010903396A0 (en) 2010-07-29 A method and apparatus for simulating a haptic response

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WO2011120094A1 true WO2011120094A1 (fr) 2011-10-06

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* Cited by examiner, † Cited by third party
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CN111414805A (zh) * 2020-02-27 2020-07-14 华南农业大学 一种触觉智能的稻-草辨识装置和方法

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US6939138B2 (en) * 2000-04-12 2005-09-06 Simbionix Ltd. Endoscopic tutorial system for urology
US6945783B2 (en) * 2002-05-21 2005-09-20 The University Of Iowa Research Foundation Interactive breast examination training model
US20070003917A1 (en) * 2003-04-17 2007-01-04 Limbs And Things Limited Medical training system for diagnostic examinations performed by palpation

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US5249968A (en) * 1991-04-17 1993-10-05 Actar, Inc. CPR manikin (piston)
US6939138B2 (en) * 2000-04-12 2005-09-06 Simbionix Ltd. Endoscopic tutorial system for urology
US6945783B2 (en) * 2002-05-21 2005-09-20 The University Of Iowa Research Foundation Interactive breast examination training model
US20070003917A1 (en) * 2003-04-17 2007-01-04 Limbs And Things Limited Medical training system for diagnostic examinations performed by palpation

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111414805A (zh) * 2020-02-27 2020-07-14 华南农业大学 一种触觉智能的稻-草辨识装置和方法
CN111414805B (zh) * 2020-02-27 2023-10-24 华南农业大学 一种触觉智能的稻-草辨识装置和方法

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