WO1991016954A1

WO1991016954A1 - Floor exercise equipment

Info

Publication number: WO1991016954A1
Application number: PCT/GB1991/000709
Authority: WO
Inventors: Roger Fell; Peter Macgregor
Original assignee: Macgregor Williams Limited
Priority date: 1990-05-03
Filing date: 1991-05-02
Publication date: 1991-11-14
Also published as: AU7772791A; GB9010021D0

Abstract

The invention relates to an improved form of floor exercise equipment. The invention provides floor exercise equipment (1) comprising a microprocessor (3) coupled to audio or visual means (5, 7) for generating instructions to a user; an array (11) of sensors (13) arranged to define a floor exercise area upon which exercises may take place; each sensor (13) being arranged to generate a presence signal and an absence signal indicative respectively of the presence or absence of an object in contact with the sensor (13); the sensors (13) being coupled to the microprocessor (3); where the microprocessor (3) is arranged to produce a signal dependent upon the presence signals and the absence signals to generate further instructions to the user for further exercises.

Description

FLOOR EXERCISE EQUIPMENT

Field of the Invention

The invention relates to an improved form of floor exercise equipment.

With the increasing recognition of the importance of keeping fit and healthy, the traditional healthy activities, such as competitive sports, are being supplanted by health and fitness clubs which are now very popular throughout the country. One reason for this is that a visit to a health and fitness club to carry out a personally designed programme of exercises can be fitted more readily into the busy life of a business person. The majority of these exercises are carried out alone and it is therefore necessary to ensure that there is sufficient incentive for the user of exercise equipment to be pushed to their limits. Thus, there have been a number of different types of exercise equipment which have been designed to ensure that the performance of the user is monitored and they are therefore given the incentive to improve their performance.

Equipment acting as an incentive is in the form of a microprocessor controlled video screen which displays a computer generated image. There are two such popular forms of equipment, one in the form of an exercise bike and one in the form of an exercise rower. In both these cases, a video screen projects the image of a competitor and the user's comparative position to the competitor. Thus, on the exercise bike, images of two cyclists are portrayed on the screen, and their relative positions illustrated dependent upon,the speed of the user's input. Similarly, with an exercise rower, the image of a competitive rower is projected on the screen, and the rower has to try to beat his competitor.

There are also forms of weight equipment which automatically change the weight to be applied to different parts of the equipment to change the severity of the exercise.

Most exercise programmes generated by health and fitness clubs include a series of free standing floor exercises. In these cases, they need to be done correctly in order for any benefit to be gained from them. In a busy club, this is often difficult for the staff to monitor.

Summary of the Invention

According to the invention, there is provided floor exercise equipment comprising a microprocessor coupled to audio or visual means for generating instructions to a user; an array of sensors arranged to define a floor exercise area upon which exercises may take place; each sensor being arranged to generate a presence signal and an absence signal indicative respectively of the presence or absence of an object in contact with the sensor; the sensors being coupled to the microprocessor; where the microprocessor is arranged to produce a signal dependent upon the presence signals and absence signals to generate further instructions to the user for further exercises. Preferably, the floor exercise equipment incorporates both audio and visual means of generating instructions to a user. Preferably, the visual means comprises a video screen displaying graphics or text generated by the

5 microprocessor. Preferably, the audio means includes means for playing music to the user. This means that the exercise equipment can be used effectively for aerobics exercise programmes which are generally carried out to music. Preferably, the audio means also includes means for lOgenerating speech which means that verbal instructions can be provided for the user.

In the preferred embodiment of the invention, the array of sensors operates based on a change in capacitance. In this case, the floor exercise area is made up of a 5continuous lower base plate and a discontinuous upper sensor area comprising a series of sensor tiles spaced from each other by air. Between the top and lower plate is a space filled with insulating material of low dielectric constant such as chipboard. Typically, the base plate and 0sensor tiles are of aluminium.

Each sensor is represented by an individual tile and the capacitance between the tile and the base plate is sensed. The flux path from each tile to the base plate can be regarded as comprised of a fixed "direct" path which passes 5from the lower surface of the tile to the base plate, and a variable "indirect" path which passes from the upper surface of the tile, through air or any medium in the proximity of the tile, to the adjacent tiles and hence to the base plate. In the case where no object is in the 0proximity of the tile, the indirect flux passes through the air and the capacitance between the tile and the base plate has a certain value.

If an object is in the proximity of the sensor tile, the dielectric constant of the indirect flux changes 5significantly, and the flux distribution changes. This changes the total capacitance between the tile and the base plate dependent upon the location and dimensions of the object and its dielectric constant. The microprocessor includes means to generate a signal indicative of the capacitance of the sensor without the presence of an object and compare it at intervals with the instantaneous capacitance of the sensor to indicate the presence or absence of an object in the proximity of the sensor.

Where the tiles are arranged in any array the adjacent tiles ensure that the flux from each tile is regular, and the direct flux is substantially normal to the tile and the base plate.

Preferably, the comparison of signals takes place at least every 160 milliseconds, i.e. more than six times per second. This is sufficient to indicate the presence or absence of part of the body on a particular area of the floor exercise area.

Preferably, the floor exercise area incorporates at least sixty four sensor tiles. Typically, the size of each sensor tile will be 150 mm x 150 mm. Typically, the space between the tiles will be 6 to 8 mm.

In most cases a number of tiles will be used to denote a single sensor area, and a positive response from one tile will result in a positive response from that sensor area.

Preferably, the microprocessor is arranged to be programmed such that the signals can be interpreted in a number of different modes so that, for example, in some exercises, each sensor will be made up of four tiles, and in other basic exercises, the sensors may be made up, for example, of eighteen tiles each. Conveniently for most exercises, the tiles can be arranged such that the outer edge tiles on the boundary can be regarded as one sensor area with the central area being divided into two, a left and a right sensor. In this case, if an object is sensed on any tile in a particular sensor area, then that sensor is considered as occupied.

The area of a tile is chosen such that a typical foot will be larger than the tile so that in all exercises, the presence of a hand or foot would span at least a pair of tiles and therefore give more than one positive signal to be read by the microprocessor.

Preferably, the microprocessor may be arranged to detect the length of time an object is on a particular sensor area. This can help identify if an exercise is being carried out correctly.

Typically, the visual message generated for the user will include a "too fast" and a "too slow" indicator together with a graphic indication of the exercise and any faults that have been detected.

It will be appreciated that this method of detecting the presence or absence of an object on a floor area will have other applications such as sensors for automatic door operation and security intruder detection.

Brief Description of the Drawings

An example of floor exercise equipment in accordance with the invention will now be described, by way of example only, with reference to the accompanying drawings in which:-

Figure 1 is a schematic block diagram of the operation of the equipment;

Figure 2 is a plan view of the floor exercise area;

Figure 3A is a schematic section showing one tile to illustrated .the principle behind the equipment;

Figure 3B is a schematic section similar to Figure 3A indicating the presence of an object; Figure 4A is a schematic section through part of the floor area to further illustrate the principle behind the equipment;

Figure 4B is a schematic section similar to Figure 4A indicating the presence of an object;

Figure 5 is a schematic circuit diagram of the connection between the sensor tile and base plate;

Figure 6 is a circuit diagram of part of the circuit;

Figure 7 A,B,C and D are graphs showing the input and output at different stages of the circuit shown in Figure

6;

Figure 8 is a detailed section through part of the floor exercise area;

Figure 9 is a circuit diagram illustrating the 16 channel sensor circuit;

Figure 10 is a circuit diagram of the practical detector circuit;

Figure 11 is a circuit diagram of the computer/sensor interface; Figure 11A is a circuit diagram of a variation of the circuit shown in Figure 11; and

Figure 12 is an illustration of the position of the sensors with respect to the tiles on the floor exercise area.

Description of the Preferred Embodiment

Floor exercise equipment 1 comprises a microprocessor 3 coupled to a visual display unit 5 and a speaker 7 both of which are arranged to generate instructions to a user 9 of the equipment. The equipment 1 also comprises a floor exercise area 11 defined by an array of sensors 13 which are arranged to detect the presence or absence of an object in contact with the sensor and feed signals to the microprocessor 3 for the microprocessor to calculate whether the exercises are being carried out correctly. The microprocessor 3 includes means (not illustrated) for feeding in different sets of work-out programmes so that a particular user 9 can decide the level of difficulty and can have a personally designed work'out programme for the floor exercises.

The Figures 3 and 4 illustrate the method by which the sensor tiles illustrated in Figure 2 operate.

The floor area 11 essentially comprises a continuous base plate 15 and a series of small tiles 17 separated from each other by air 18, the base plate 15 by an insulating material 19 of low dielectric constant. Figure 3 illustrates the physical lay out and approximate flux pattern when only one tile is used and no object is in contact with the top plate 17. With no object near the plate 17, the indirect flux is linked through air and is then much weaker than the direct flux through the dielectric 19. If an object 21 as shown in Figure 3B is placed in contact with the sensor plate 17, the dielectric constant of the indirect flux increases significantly and the flux distribution changes. When the tiles 17 are in an array as illustrated in figures 4A and 4B the direct flux from each tile 17 to the baseplate 15 is substantially normal. When an object is in contact with one or more tile 17 the flux pattern is changed as shown. The total capacitance is then altered by an amount which depends on the surface area of the object 21 in contact with the sensor and its dielectric constant. The sensor equivalent circuit is approximately that shown in Figure 5 in which the dielectric constant of the material 19 is designated k and the dielectric constant of the objects material 21 is kl. The total capacitance change occurs as a result of the change in C2 which illustrates the position when an object is in contact.

The equipment operates by generating a logic signal indicating the presence or absence of an object 21 on a tile 17 by detecting the capacitance change it causes. The capacitor represented by the tile Ct and a reference capacitor Cr are connected in series and driven by signals ol and o2 which are of equal amplitude V but anti-phase (see figures 7A and 7B) . The relative size of the two capacitors determines the amplitude and phase of the signal oj at their junction. Thus, if Ct > Cr, then oj is in phase with ol, whereas if CT < Cr, then oj is in phase with o2. This phase is detected by an exclusive-OR gate 23 after first processing the signal oj using a limiting amplifier 25 to make its amplitude independent of the relative values of the two capacitors.

The detailed construction of the floor exercise area is illustrated in Figure 8. The capacitor sensor array 11 constructed as a foot sensor for the aerobic exercise system uses two sheets of 18 mm marine chipboard 27 and 29. These make up the area of dielectric illustrated as 19 in Figure 3. The sensor tiles 17 are made up of 0.8 mm aluminium sheet and the base plate 19 comprises a 0.8 mm aluminium sheet. An 8 by 8 array of 150 mm sensor tiles 17 is arranged on a base board 31 which in this case, is 4 foot by 4 foot (1.22 x 1.22 metres). Each sensor tile 17 is connected to a coaxial cable 33 which interfaces to the sensor electronics. A tile isolator 35 is provided which comprises a thin sheet of insulating material which provides electrical isolation between the user and the sensor electronics. This can be appropriately printed and can disguise the sensor tile 17 and/or carry a logo or instructions.

A sensor screen 37 is provided beneath the base board 31 to enhance the electrical performance of the sensor. In the unscreened version of the sensor illustrated in Figures 3 and 4, there are also capacitances between the capacitor plates and ground which are omitted from the equivalent circuit illustrated in Figure 5. The effect of these capacitances is to modify the required reference capacitance .according to the properties of the material below the sensored base plate 19, thus making on site adjustment necessary. By connecting the screening plate 37 to an unused o 2 output signal from'one of the sensor interface cards (to be described in^' more detail), the base plate 19 and the sensor screen 35 are driven by identical signals so that there is no flux between them. Anything below the sensor screen 35 then has no effect on the sensor operation and the need for on site adjustment is removed.

The sensor electronics can convert the capacitance values of each sensor plate 17 into logic signals for use by the microprocessor 3. The circuit incorporates four identical circuits as shown in Figure 9 each capable of handling 16 sensor plates.

An external clock signal 38 is applied to one gate of the 74HC04 hex invertor which acts as a buffer outputting the internal φl signal which drives each signal input of the four 74HC125 quad tri-state buffers 39. The remaining inverter gates 41 are connected in parallel to provide the base plate drive signal previously referred to as o2. A 4- bit tile address 40 applied to a 74HC154 decoder 43 causes one of its 16 outputs to go low, provided always that the card enable signal 44 is low. Since each of the decoder 43 outputs connects to one of the tri-state buffers 39 enable inputs the effect is to produce the ol drive signal at the output of the selected buffer whilst the remaining 15 buffer outputs remain in the high impedance state.

As shown in Figure 10, the active ol output drives the coaxial cable connected to its tile capacitance via a reference capacitor 45, at present a variable (trimmer) capacitor. The junction between the reference capacitor and the coaxial cable is then the source of the oj signal referred to in figures 6 and 7. Each of the 16 channels uses 3 of the 6 invertors of a 74HC04 for signal detection and limiting. One gate is used with a feed-back resistor in a quasi-linear mode, the remaining two operate as buffers. The result is that the detection circuit output signal approximates to either ol or o2 depending on the relative magnitudes of the tile capacitance and the reference capacitance.

Each of the 16 tile signal detection circuits connects to a signal input of one of the two 74HC354 data selectors 46. Since these selectors are driven by the same address signals 40 as the 74HC154 decoder 43, the output from the data selectors 46 is always the detector output signal for the active tile. Phase comparison between this signal and the ol reference is performed by a 74HC86 exclusive - OR gate 48. The output of this gate 48 drives a low pass filter 50 to produce an analogue tile output signal 52. A transistor and pull-up resistor provide a logic signal 54 to indicate the state of the addressed tile.

One embodiment of the computer interface hardware illustrated in Figure 11 consists of a parallel output port 47, a parallel input port 49 and a timer-counter device 51. The timer-counter 51 is programmed to generate a sensor clock input signal 53 of typically 200 kHz and an internal interrupt signal at intervals of typically 1 mS. The interface software consisting of 4 interface cards 54, when activated by the interrupt signal, reads the state of the selected tile or tiles from the input port 49 and sets the appropriate elements in an array of memory locations holding the tile states. The interrupt programme then sets the address of the next tile on the output port, activates the appropriate enable signals and returns to the main programme.

Assuming each of the 64 tiles is interrogated in sequence using a 1 mS interrupt period, then each tile is interrogated every 64 mS, or rather less than 16 times per second. Thus, any contact with the board lasting more than 1/16 second is bound to be detected, as is any lack of contact. A requirement of the capacitance sensor array 11 when used in the context of the aerobic exercise system is that it must be, to some extent, fault tolerant. The application software is designed to achieve this objective. At power-on time, when it can be guaranteed that the floor exercise area is unoccupied, the software scans the sensor to check that every tile is returning a 'vacant' signal. Any tile 17 returning an 'occupied' signal is assumed to be faulty and marked as such in a 'tile availability map' used to mask the signals from the tiles, thus effectively disregarding signals from faulty- tiles making them permanently unoccupied.

A further embodiment of the computer interface is illustrated in Figure 11A in which a four channel analogue to digital convertor 55 with typically eight bit resolution monitors analogue output signals from the interface cards 54. The interrupt programme reads the convertor output value and the process of determining whether a tile is occupied or unoccupied is performed in software by comparing this convertor output with a previously determined threshold value. The software is designed to dynamically adjust this threshold value to accomodate slow changes in tile output signal caused by effects such as thermal drifts of component values. In this way, rapid changes in capacitance of magnitude much smaller than the slower random changes can be reliably detected and the tile sensitivity is greatly increased.

In the aerobic exercise software, the 64 physical sensor tiles are considered in groups forming a lesser number of logical tiles. These logical groups are exercise specific.

Figure 2 shows an example of three logical groups, boundary, left and right, containing 28, 18 and 18 physical tiles respectively. If any of the physical sensor tiles within the group is occupied, then the logical tile is also considered as occupied. Since the size of a foot is greater than the size of a physical sensor tile, it is unlikely that the failure of a single physical tile will effect the output of the logical tile.

It will be appreciated that the capacitance sensor array could be used in numerous additional applications such as a sensor for automatic door operation or for intruder detection.

Claims

1 Floor exercise equipment (1) comprising a microprocessor (3) coupled to audio or visual means (5,7) for generating instructions to a user; an array (11) of sensors (13) arranged to define a floor exercise area, upon which exercises may take place; each sensor (13) being arranged to generate a presence signal and an absence signal indicative respectively of the presence or absence of an object in contact with the sensor (13); the sensors (13) being coupled to the microprocessor (3); where the microprocessor (3) is arranged to produce a signal dependent upon the presence signals and absence signals to generate further instructions to the user for further exercises.

2 Floor exercise equipment according to claim 1 which includes both audio (7) and visual means (5) for generating instructions to a user.

3 Floor exercise equipment according to claim 1 or 2 in which the visual means (7) comprises a video screen displaying graphics or text generated by the microprocessor (3).

4 Floor exercise equipment according to claim 1 or 2 in which the audio means includes means for generating speech so that verbal instructions can be provided for the user.

5 Floor exercise equipment according to claim 1 in which the floor exercise area (11) is made up of a continuous lower base plate (15) and a discontinuous upper sensor area comprising a series of sensor tiles (17) spaced from each other by air (18), and between, the base plate and the upper area is a space filled with insulating material (19) of low dielectric constant.

6 Floor exercise equipment according to claim 5 in which the base plate (15) and the sensor tiles (17) are of aluminium and the insulating material (19) is chipboard.

7 Floor exercise equipment according to claim 5 in which the microprocessor (3) includes means to generate a signal indicative of the capacitance of the sensor without the presence of an object and compare it at intervals with the instantaneous capacitance of the sensor to indicate the presence or absence of an object in the proximity of the sensor, the comparison of signals taking place at least every 160 milliseconds.

8 Floor exercise equipment according to claim 5 in which the floor exercise area incorporates at least sixty-four sensor tiles (17).

9 Floor exercise equipment according to claim 5 in which the microprocessor (3) may be switched from a first mode in which each sensor (13) comprises a first set of tiles (17) to a second mode in which each sensor comprises a second set of tiles (17) including a different number of tiles (17) than the first set of tiles.

10 Floor exercise equipment according to claim 1 in which the microprocessor (3) is arranged to detect the length of time an object is in- contact with a particular sensor area.