WO2005067796A1

WO2005067796A1 - Elastic textile structures for sensing body movements

Info

Publication number: WO2005067796A1
Application number: PCT/IB2003/006172
Authority: WO
Inventors: Michael Rufer; Fridolin Voegeli
Original assignee: Michael Rufer; Fridolin Voegeli
Priority date: 2003-12-19
Filing date: 2003-12-19
Publication date: 2005-07-28
Also published as: AU2003285679A1

Abstract

System for evaluating and monitoring physiological parameters in living systems' bodies comprising sensor devices, sensor holders and signal processing devices for assessing body form, body posture and body movements, by measuring contraction and elongation of surfaces which are in direct contact to the body surface, around vessels and cavities, above muscles and joints, along the spine and along the extremities by using highly elastic textile structures wherein said sensor devices are the elastictextiles it selves. The sensors are integrated in the supporting or protecting textile as highly elastic threads that are preferably made of electrically conductive, resistive plastics, changing their resistance as nearly linear function of elongation.

Description

ELASTIC TEXTILE STRUCTURES FOR SENSING BODY MOVEMENTS

The present invention relates to the assessment of living systems' body form, body movement and body movement related physiological parameters that can be evaluated by measuring the contractions and elongation of the body surface, around vessels and cavities, above muscles and joints, along the spine and along the extremities.

For various applications in human medicine and training, posture, movements, joint angles, steps, etc. have to be measured, e.g. chest measurement for monitoring pulmonary activity, leg measurement for monitoring blood flow, trunk muscles contractions and vertebral distances for posture analysis, finger-joint angles for virtual manipulation control.

For these tasks e.g. devices of mechanic, optic, electromagnetic and ultrasonic bases are used. All these known systems for the assessment of human body posture and 3-dimensional positions and distances as well as of the related movements have one significant drawback - they all are demanding additional, more or less sophisticated sensors, to be fixed on the skin or on the clothing, in the surrounding room, or in complex visual apparatus systems. Many of these sensors' signals have to be captured and evaluated with extensive electronics and signal processing efforts.

Plethysmographic measurements are best practice in biomedical analysis, some of them have become routine. Most of them are coupled with additional mechanical, piezo-electric, ultrasound, inductive or capacitive transducers to be fixed somewhere on the outside of the functional garment. The US publication US2002082505, gives an impression about the difficulties of capturing the resulting small elongation signals using mechanical transducers. Most of the systems described can only be applied in stationary, quasi-clinical environment and therefore have never been widely used. The present invention's object is to provide and add a cheap and simple system for evaluating and monitoring physiological parameters in living systems' bodies with sensor properties to the textiles the human object is already wearing, either as protective clothing like shirts, leggings, track-suit, etc. or as functional garment like bandage, support, corset, holster, glove, etc., and to define a universally applicable method for measuring the body form and posture, the limb positions and movements, precisely and automatically, while proving to be cosmetically acceptable and nearly zero physically restraining.

This object is achieved by adding variable electrical resistivity, that can easily be measured, to part of the elastic threads and cords woven into or applied on fabrics or tissues for modern technical textiles and functional garments and by providing a simple method for assessing multiple such resistors in simple electronic circuits and efficient signal processing.

Further advantages and preferred applications of the invention are disclosed in the dependent claims and in the following description in which an exemplified embodiment of the invention and the use thereof is described with respect to the accompanying drawings in which:

FIG. 1 shows the use of such systems in functional garments on the human body capturing circumference variations;

FIG. 2A shows a respiration sensor belt integrated into a bra;

FIG. 2B depicts a cross-section of said belt that is an integral, supporting part of the bra;

FIG. 3 depicts a cross-section of a single-thread "endless" sensor-tissue-tape; FIG. 4 shows the applications of such systems in protective clothing on the human body above joints, assessing the elongation of the skin, caused by the angle of the joint;

Fig. 5A shows a block diagram of the comparator configuration for the resistance measurement;

Fig. 5B shows the voltage across capacitor C during resistance measurement;

FIG. 6 gives a detailed application example as sensors in a glove for virtual reality;

FIG. 7 shows the model of mapping the womb of a pregnant woman, for the monitoring of fetal movements;

FIG: 8 depicts a plaster-like system mapping a person's back, capturing curvature and off-balance of the spine;

FIG. 9 shows the application of such systems in carrying human bodies in a car seat;

FIG. 10 shows the use of such systems in carrying human bodies, being carried by human bodies, e.g. in a rucksack.

Specific numbers dedicated to elements defined with respect to a particular figure will be used consistently in all figures if not mentioned otherwise.

The system for the assessment of body form, body movements and body movement related physiological parameters, according to the invention, uses highly elastic resistive threads as sensors, measuring their resistance variation caused by the elongation of the thread on the skin surface. Such highly elastic thread or threads are worked into or onto fabrics or tissues as for example a single thread or as a complex matrix of threads for sensing linear or planar changes of elongation of the fabric or tissue. The threads are naturally integrated in parts of clothing or supports where the highest changes of elongation in the underlying elastic skin are expected, to keep the cloth or the support in a well defined position, without folds, as the underlying skin also does not produce folds. All the clothing and all the modern functional garments we wear are full with such elastic threads and cords, in all variations and in all configurations to which the resistive threads as sensors can be added or which elastic threads are partly replaced by the elastic and electrically resistive threads. By this way the sensor devices for measuring the change in elongation are the elastic textiles themselves, regardless of the number of electrically resistive threads worked into or onto the fabric or tissue of said textile.

The formulas for calculating resistance and resistance changes (delta) due to length changes in a wire or thread (of length L, diameter D, resistivity r, resistance R) are :

ΔR / R = ΔL / L -2 ΔD / D + Δr / r

As long as the changes are small and are along the central axis (there is no other strain direction possible in elastic threads) one gets the well known formula for strain gages:

ΔR / R = k * ΔL / L

It is a characteristic of highly elastic threads, with elongation at rupture of several hundred percent, that the strain gage formula can be applied over a long part of the elastic elongation. Measurements in such threads have shown good linearity and small hysteresis over a wide usable range.

Modern elastic cloth and bands have more and thinner threads and offer more such sensor opportunity than the textiles just a few years ago. The cloths are woven so as to be elastic in all directions, bands and supports can be designed reinforced, applying stronger elastic elements to keep and support special forms, at the same time being ideally situated to be cheap and effective sensors for measuring and reporting their own complex form.

The resistive sensors can be tapped at any distance, allowing for evaluation of the distribution of the elongation changes along the whole axis. For example, a sensor running over the whole finger can be segmented with two simple intermediate contacts in order to capture single flexion of all three joints.

Figure 1 depicts preferred textile sensor belts for sensing physiological parameters. The two persons show the use of such sensor systems in measurement bandages (functional garments) on the human body, capturing circumference variations, monitoring and evaluating underlying physiological activities. By using the woven-in elastic elements of the functional garment and adding resistive sensor qualities to it, the resulting device becomes minimal in size and weight, not physically restraining, but cosmetically acceptable. The band with the sensor integrated can be made in one closed part and due to the high elastic material it can be pulled over the extremities or over the head, or it can be manufactured as open bandage to be closed easily using buckles or even Velcro closures. Two wires only (not shown in the figures) can connect the resisitive sensor or sensors to the signal processor. Physiological parameters can be sensed by the preferred depicted sensor belts 21...28, these are for example a Chest respiration belt 21 for capturing chest circumference variations, evaluating breath rate and breath amplitude for a qualitative assessment of the breathing (deep, normal, flat). Calibration of the respiration volume can be done by parallel unforced air-flow measurement. An abdominal respiration belt 22 can be added to the chest belt 21 for improved respiratory analysis. For monitoring blood flow, an upper arm band 23 will be applied. Further bands are e.g. a wrist band 24, to monitor heart rate by detecting blood flow pulses and lower limb bands 25, to monitor blood flow (restrained or unrestrained) in the lower extremities. It is a characteristic of such circumference variations in the human body that the elongation is not evenly distributed over the whole "circle" (that never is a circle), due to underlying bone, muscle and vessel structures. Most sensors of prior art therefore have at least one part of the band that is not extendable or have to provide for sliding mechanism in order not to generate friction between the "undefined" skin and the "solid" band and sensor. The new preferred integrated highly elastic threads extend only where the surrounding elastic textile extends and remain otherwise and elsewhere in perfect shape and position with the textile and the body.

Also training and fitness parameters can be measured and controlled by the depicted sensor bands like chest and abdomen strain bands 26, to measure the strain applied in practicing, competition, work, etc., to verify training progress and detect and prevent dangerous load situations. Arm strain bands 27 are used to measure strain excesses that lead to tendon problems, and leg load bands 28 are used to monitor exercise and work load, as well as onset of cramps.

The cheap manufacturing and easy handling of such sensor systems will enable wide use of these plethysmographic methods, by doctors and patients, in doctors' offices and at patients' homes - hopefully like the blood pressure measuring wrist cuff, unknown 10 years ago. All the respiratory and blood flow related diseases show the typical trend of chronic diseases. Starting out at low level, not being detected early by easy measurements, developing later unnoticed and coming to the doctors attention only a few years before the deadline. Distributing cheap sensors, offering short and easy screenings to large groups, the high number of hidden cases could be detected early and in time for repairing medication, therapy, training and lifestyle.

Figure 2A shows the inventive sensor built into the supporting belt of a woman's bra, a garment of daily use, to be washed and disposed of after some time. The elastic sensors 34 integrated into the supporting belt of the bra 31 form a perfect respiration belt, to monitor respiration, continuously. The sensors 34 can be activated and used by simply connecting the conductive resistive threads with push buttons 35 at their end to a signal processing unit 32. Disposable sensors will be feasible for many medical, care and wellness application.

Figure 2B depicts a cross-section of a part of said belt that is an integral supporting part of the bra with a strong supporting elastics 33 and highly elastic resistive threads 34 which are soft and used as sensors. A push button 35 is used for connection of the conductive sensors 34 to a processing unit. This figure further shows how, with different weaving techniques the outer side of the belt can be made flat and protectively hard, in a "monofil" technique 36, where as the inner side of the belt, due to "multifil" technique 37 fells smooth and soft, comfortable on the skin.

The present invention can be applied also in single thread 48, tape-like "endless" textile sensors, dispensed from rolls in manufacturing, wherein the elastic resistive threads are worked into or onto a support textile 49 for stitching as shown in Figure 3. The tape can easily be cut with a sewer's scissors to variable pieces, can be configured and stitched on to any elastic textile surface, the ends can be crimped to very thin wires that connect to the processing unit. Simple or complex monitor and analyzers are already available. A special version, with plaster back on the textile tape, can be taped down directly on the skin.

Prior art sensor technology for movement monitoring and analysis has been an insurmountable obstacle for extensive field work and frequent experiments in the daily life environment of patients at the hospital and at home, of athletes in the gym and on the mountain slope, of people at work and at leisure, of elderly citizens with their stick, of soldiers with all their load, etc. Most experiments have to be prepared, arranged, executed and then evaluated in the lab, using lab data acquisition equipment, using experts' visual evaluation. In DE 101 26 539 A1 a concept is revealed, which is called "Sonobone" which concept is the first portable, wearable sensor system for field-experimental use. Figure 4 shows the use of the innovative sensors stitched on to protective clothing on the human body e.g. track suit, leggings, shirts or socks, etc., assessing the elongation of the elastic textile covering the elastic skin over the joint, caused by the angle of the joint. Such sensors are positioned for example: over the elbows and forearms 41 , measuring angles; over the knees and foot 42, monitoring steps; over hip joint 43 and over femoral 48; over the calves 44; on the shoulders 45; along the spine 46 as "Spine-Spider" mapping the back for bending, leaning, torsion, etc or on a neck support 47, monitoring alertness of the person.

Different sensors which are handled as different measuring channels can be calibrated by recording and storing their end position values as references. The device can then be started and the resistor signals are evaluated, transmitted, or stored and transmitted later, and software programs (e.g. public domain programs) help to visualize the position of the body part.

Digital and mixed signal processing of simple electrical signals has started to replace expensive mechanical and optical systems for the assessment of free movements. The preferred invention offers the most common and cheapest direct sensor, variable resistors incorporated in highly elastic textile threads, to report their own elongation in order to calculate complex forms, curvatures and angles of the textile; in place of more sophisticated, mainly optical, ultrasound or electromagnetic based distance measurement. Inexpensive systems for the precise measurement of resistive sensor elements have been in use for long time. Microcontrollers (e.g. the well known Mixed Signal Processors MSP430 family) have become preferred in wearable sensors for physiological measurement. Minimal part count and high precision is achieved by comparator techniques. Comparators are optimized to precisely measure resistive elements using single slope analog-to-digital conversion. In our case, elongation can be converted into digital data using such resistive threads, by comparing the capacitor discharge time through the resistive thread (Rmeas) to that of a reference resistor (R_ref). Using the fact of change in resistance due to elongation for highly elastic threads and cords, dotted with conductive micro-particles, offers a precise and inexpensive measurement of resistive elements as recommended in Mixed Signal Processing.

Figure 5A shows the block diagram of the comparator configuration in the MSP controller. Except for the two elements R_ref and C, there are no other external components used. A multitude of R_mΘas can be connected to the capacitor, by activating ordinary I/O pins on the processor or on a multiplexer. The preferred resistor measurement is based on a ratiometric conversion principle.

Figure 5B shows the voltage V_c across capacitor C during resistance measurement, wherein T1 , T2 are charge and discharge times for the reference resistor R_ref and T3, T4 are charge and discharge time for sensor Rm_eas- The solution of two exponential equations describing the capacitor discharge for reference resistor R_ref and sensor Rme_as leads to a simple equation for the calculation of Rmeas- The ratio of the two capacitor discharge times is calculated as shown below. Time "t" is measured in number of time-units N of an internal clock generator. The supply voltage V_cc and the capacitor value C shall remain constant during the conversion and are independent of battery voltage level, temperature, vibrations, etc., but are not at all critical, since they cancel out in the ratio :

Nmeas / N_ref = (-Rmeas * C * ln(V_refΛ _Cc)) / (-Rref * C * ln(V_ref/V_cc))

Rmeas = Rref * N_meas / N_ref

Due to the precision of ratiometric resistance measuring techniques, elongation variations can be detected already over small distances of a few centimeters, when the sensors are applied in the direction of the elongation. This allows e.g. for the measurement of chest circumference variations with a resolution of some 50 digits per mm, as used e.g. in the "Sensor Bra" in figure 2A. This low cost material allows also for the realization of surface mapping systems using mesh-type or coordinate-type grids of multiple sensors. These mapping systems enable monitoring of complex posture and movement patterns in multiple axis and have proven to be an excellent tool for orthopedic analysis and for work medicine monitoring, as reported by Friedrichs et al. in DE101 26 539 A1.

Through this invention, the inventors open up completely new areas of passive, non-invasive sensor applications. Figure 6 depicts a sample of a glove that is offered to experimenters to use and test in many more applications then the inventors could ever think of and work on. Single thread sensors 51 , each covering 3 joints 52, divided by 2 contacts 53 and a Mixed Signal Processors board 54, with a 3-axis accelerometer 55 as position sensor to assess movements of the hand as a whole.

Figure 7 depicts the configuration of a novel body-surface mapping that allows for the monitoring of the womb of pregnant women, for the assessment of fetal movements and the detection of onset of contractions with "horizontal" threads 71 , to be shortened in contractions and with "vertical" threads 72 to be elongated in contractions. The sensors are integrated in a coordinate like grid into the underwear or into a plaster on the womb for monitoring movements of the unborn underneath the highly elastic skin, monitoring the progression of contractions and finally to measure stress and strains around the birth canal during birth. In DE 100 19 634 A1 , there is given a first approach to monitor one short part of the long months just before the onset of and during the contractions. Measurements in the months before shall facilitate a full pregnancy monitoring, where the mapping of the womb will be added to additional ECG, ultrasound and audio signal analysis.

Figure 8 shows a plaster 61 that can be put on the back 62 of an assembly line worker, a waiter, a typist, a pianist, a school kid, a soldier, etc. to monitor the posture and to alarm on changes to bad positions, on physical fatigue and to ask for compensating stretching and so on. This device can be disposed after some time of use, at low cost.

The highly elastic threads of this invention have also been woven into and applied onto cover textiles and supporting bands that fit to the human body, in systems that have to carry humans for example seats, especially car seats, wheel chairs, beds, pillows or safety nets etc, or are carried by people like rucksacks, oxypacks or bags, etc. Figure 9 shows a car seat with 4 horizontal support sensor bands 81 , forming a four-quadrant-sensor for assessing the drivers position and sensor threads 82, woven into the back cover, segmented, to monitor the posture of the driver. The sensors integrated to the car seats allow detection, if the seat is occupied for triggering the airbag functionality, to asses the position of the driver and his alertness, to alarm in case of bad position or position changing into bad. Similar seat monitoring can be done inexpensively e.g. in public transport vehicles, to supervise occupation and control people flow.

Figure 10 depicts the use for monitoring the weight of an Oxypack (oxygen tanks). The load-carrying bands have been designed to extend some 25% for the full pack, coming back to some 5% elongation for the empty pack. The strong elastic threads 83 acting like a spring balance, generating a weight-elongation signal and transmitting it to the supervisor for predefined action. The sensor can be integrated also in flexible supporting belts for containers being carried on human bodies, like rucksacks, emergency packs, arms and ammunition, tools and materials, ropes and climbing gear, etc., to monitor the load and its influence on posture, movements and fatigue of the bearer, triggering alarms in dangerous situations, off balance state and fall of the load or the bearer.

There is a large field of use of the inventive sensors for evaluating and monitoring and measuring physiological parameters in living systems' bodies. For example in plethysmographic monitoring and measurement of body cavities and vessels, such as in a band or bandage around an arm, a leg or the wrist, to measure changes in circumference or pressure, monitoring blood flow and blood pressure in the vessels under the band, evaluating heart-rate and heart-rate variations, trigger alarms in case of insufficient flow or sudden cardiac arrest. Further in strength monitoring and contraction measurement of chest, abdomen, arm and leg muscles, in bandages around said body parts, to measure changes in circumference and pressure, monitoring the efforts for and the effects of specific movements, in work, sports, daily life, evaluating workload and frequency, evaluating energies and fatigue patterns, triggering alarms in case of dangerous loads or fading strength.

These sensors can also be used in goniometric monitoring and relative spatial displacement recording, as elongation sensors over the big joints in the body and in the limbs and between specific points on the trunk, especially along the main- axis of the spine, monitoring joint flexion angles and measuring the elongation of vertical, horizontal and crossed distances on the body surface skin, evaluating patterns of specific movements in work, sports, daily life, evaluating correct and badly compensating posture changes, detect degenerative posture adaptations, in stress and fatigue, triggering attention signals to the bearer, sending alarms to nursing and supervisory personal, reporting to coaches and caregivers. Also for computer-based calculation of limb and torso positions and human finite-element models, for the analysis of complex, transient movements and positions in work, sport, daily life, as base for the design of aids and the elaboration of improvement training and as tool for the monitoring of the outcome of said improvements, in the real world environment.

A further application of the inventive sensor is the use of the measured goniometric and distance values in "virtual reality" to make a "copy" of the human body and its movement, for computer animated and simulated games and jobs, or using the human hand in a sensor-glove for remote controlling of a robot-hand manipulations, e.g. in handling dangerous objects or when doing specialized surgery on distant patients. One to multiples sensors can also be stitched or applied on clothes to do experimental tests and quick verifications in the patients home and daily life environment, capturing data that immediately can be transmitted and assessed by remote experts without having to deploy complex sensors and heavy apparatuses.

Sensors, woven into covers and integrated in reinforcing structures and supports carrying human bodies or body parts, in chairs, car seats, bike saddles, wheel chairs, beds, pillows, head and arm rests in the bath, safety nets, etc. can be used for detecting the presence of the body and reporting occupancy, monitoring position changes and movements, assessing alert and sleep status of the person, triggering alarm in dangerous situations, off balance state and fall of the body, but also for disabling unwanted actions, like firing all passengers' air-bags on empty seats.

The invention is not restricted to the working examples as described above and there are many more applications to be thought of and to be migrated from prior art sensor technology to the new preferred technology, resulting in significant reductions in sensor cost, improvement in sensor device usability, in wearability and therefore in applicability for field deployment and decentralized patient monitoring, the goal of future eHealth (electronical health monitoring).

Claims

1. A System for evaluating and monitoring physiological parameters in living systems' bodies, comprising sensor devices, sensor holders and signal processing devices, which system assessing body form, body posture and body movements, by measuring contraction and elongation of surfaces which are in direct contact to the body surface, around vessels and cavities, above muscles and joints, along the spine and along the extremities, using highly elastic textile structures wherein said sensor devices are the elastic textiles it selves.

2. Sensors for a system as claimed in claim 1 integrated in the supporting or protecting textile as highly elastic threads that are preferably made of electrically conductive, resistive plastics, changing their resistance as nearly linear function of elongation.

3. Sensors as claimed in claim 2, characterized through their ability to follow and measure the surface of the skin exactly in resistance changes, embedded in the fully elastic textile for cloth or plaster covering said body part, without any need for additional mechanical fixtures or supports.

4. Sensors as claimed in claim 2, integrated as functional strain element in reinforcing supports, belts, harnesses, corsets, etc., assessing position and strength of the reinforcing device by an elongation dependant resistance signal, while being an integral part of said reinforcing device, without any need for additional sensors materials and application.

5. Sensors as claimed in claims 2 through 4, used with a ratio metric conversion electronics to capture multiple sensors' signals for automated digital signal processing on-site, for the real-time evaluation of critical and fatal movement or physiological events and the immediate, local and remote, trigger of alarms and actions, of preventive and emergency type.

6. Use of sensors as claimed in claims 2 through 5 in plethysmographic monitoring and measurement of body cavities and vessels, such as in a belt around the chest (21) or the abdomen (22) to measure changes in circumference, evaluating the respiration parameters breath-rate, breath- volume, normal and pathological breath-patterns, trigger alarms in case of apnea or sudden breath-stop.

7. Use of sensors as claimed in claims 2 through 5 in plethysmographic monitoring and measurement of body cavities and vessels, such as in a band or bandage around an arm, a leg or the wrist, to measure changes in circumference or pressure, monitoring blood flow and blood pressure in the vessels under the band, evaluating heart-rate and heart-rate variations, trigger alarms in case of insufficient flow or sudden cardiac arrest.

8. Use of sensors as claimed in claims 2 through 5 in strength monitoring and contraction measurement of chest, abdomen, arm and leg muscles, in bandages around said body parts, to measure changes in circumference and pressure, monitoring the efforts for and the effects of specific movements, in work, sports, daily life, evaluating workload and frequency, evaluating energies and fatigue patterns, triggering alarms in case of dangerous loads or fading strength.

9. Use of sensors as claimed in claims 2 through 5 in goniometric monitoring and relative spatial displacement recording, as elongation sensors over the big joints in the body and in the limbs and between specific points on the trunk, especially along the main-axis of the spine, monitoring joint flexion angles and measuring the elongation of vertical, horizontal and crossed distances on the body surface skin, evaluating patterns of specific movements in work, sports, daily life, evaluating correct and badly compensating posture changes, detect degenerative posture adaptations, in stress and fatigue, triggering attention signals to the bearer, sending alarms to nursing and supervisory personal, reporting to coaches and caregivers.

10. Use of sensors as claimed in claim 9, integrated in more or less complex plasters (61) to be stuck on a part of the back (62), as a disposable posture monitor, with the evaluating signal processor giving feedback signals to the bearer for on-line teaching and supervision.

11. Use of sensors as claimed in claims 2 through 5 in goniometric monitoring and relative spatial displacement recording, as elongation sensors over the big joints in the body and in the limbs and between specific points on the trunk, especially along the main-axis of the spine, monitoring joint flexion angles and measuring the elongation of vertical, horizontal and crossed distances on the body surface skin, for computer-based calculation of limb and torso positions and human finite-element models, for the analysis of complex, transient movements and positions in work, sport, daily life, as base for the design of aids and the elaboration of improvement training and as tool for the monitoring of the outcome of said improvements, in the real world environment.

12. Use of sensors as claimed in claim 11 , using the measured goniometric and distance values in "virtual reality" to make a "copy" of the human body and its movement, for computer animated and simulated games and jobs, or using the human hand in a sensor-glove for remote controlling of a robot-hand manipulations, e.g. in handling dangerous objects or when doing specialized surgery on distant patients.

13. Use of sensors as claimed in claim 11, one to multiples, stitched or applied on clothes to do experimental tests and quick verifications in the patients home and daily life environment, capturing data that immediately can be transmitted and assessed by remote experts without having to deploy complex sensors and heavy apparatuses.

14. Use of sensors as claimed in claim 9, integrated in a coordinate like grid into the underwear or into a plaster on the womb of a pregnant woman, to monitor movements of the unborn underneath the highly elastic skin, to detect onset and to monitor progression of contractions and finally to measure stress and strains around the birth canal during birth.

15. Use of sensors as claimed in claim 5, woven into covers and integrated in reinforcing structures and supports carrying human bodies or body parts, in chairs, car seats, bike saddles, wheel chairs, beds, pillows, head and arm rests in the bath, safety nets, etc. detecting the presence of the body and reporting occupancy, monitoring position changes and movements, assessing alert and sleep status of the person, triggering alarm in dangerous situations, off balance state and fall of the body, but also disabling unwanted actions, like firing all passengers' air-bags on empty seats.

16. Use of sensors as claimed in claim 5, integrated in flexible supporting belts for containers being carried on human bodies, like rucksacks, emergency packs, oxygen tanks, arms and ammunition, tools and materials, ropes and climbing gear, etc., to monitor the load and its influence on posture, movements and fatigue of the bearer, triggering alarms in dangerous situations, off balance state and fall of the load or the bearer.