DE19619899A1 - Bicycle data recorder determining travel and rider data with recording and storage facilities - Google Patents

Abstract

The bicycle data recorder includes a central processor, a storage, a display and an interface. The sensors include a distance sensor, a pitot head true air-speed sensor, an air pressure sensor. Also sensors determining a personal performance e.g. a pedal frequency sensor and a pulse frequency sensor as well as sensors for temp., pressure and other parameters. The various values can be integrated to provide information regarding daily distance covered, the average speed taking account of local conditions. So that a total performance curve can be established, to provide a standard as a basis for training improvements and as a universal comparison.

Description

For several years, preferably muscle-powered vehicles have been driving bicycles, electronic speed and distance measuring devices, so-called bicycles computer, on the market. These devices are capable of physical quantities such as time, distance, cadence, incline and the rider's pulse rate take and these sizes, as well as sizes derived from them (e.g. Speed speed, average speed, max. Speed etc.) immediately display on an electronic display.

With stationary ergometers or exercise bikes, it is also possible to Pre-program route profiles that show the load in sections specify a certain time or distance unit. Ergometers are thus in the Able to increase performance over the given load and cadence determine and also record over the course of the route. It is the same possible, the current performance with a already during a training session compare stored performance. There can also be fictitious benefits were programmed on a route so that driving with a "Opponent" is possible.

This type of performance determination is limited to stationary devices. There not only the performance but also the driving technique should be trained, it makes sense to carry out a performance assessment on the real bike.

For a performance assessment on a real bike is different from stationary ergometers the additional detection of driving resistance, such as. B. Air resistance, rolling resistance, gradient resistance and acceleration resistance stood, required.

So far, these driving resistances can only be recorded with a measuring crank, their purchase and assembly on the bike expensive and complex and therefore in is usually unsuitable for the cyclist.

Thus, the average speed usually serves as a measure of that performed. The average speed you end up at achieved training session, can be well with the average speeds of previous training units that make sense over the have run the same route, compare and thus allow an assessment the development of personal performance. This observation shows two problems:

• 1. An objective comparison with previous training units is achieved based on the average speed only at the end of a training session possible. Now it is no longer possible for the driver to get one obtained from it Implement performance assessment and motivation as the training session increases End is. During the next training session, the driver only has his gut to the previous training session. What he lacks is an immediate one Objective possibility to compare the current driving data (e.g. speed speed, performance) with the corresponding driving data from a previous trip unit that has usefully led the same route, or with Specifications of the trainer. This would give the driver a personal march table that provides him with individual driving data during the training session.
• 2. The average speed only represents the service provided inadequate, since the driving resistances are not recorded and this is the case is not a real performance assessment. When real power is determined, the driving resistances are taken into account with which an exact statement is made during and after the training session about the service provided. This performance determination allows the exact knowledge of the service provided depending on the external Circumstances. Thus, e.g. B. the service provided by a trai unit with strong headwinds despite the low average speed be higher than in a training session without a headwind with high Average speed. For the same reason, the average speed doesn't allow one out meaningful comparison of training units across different Run routes (flat or mountainous).

By capturing and recording the conditions of a real driving stretch (training session) such as B. distance, time, speed, acceleration, It is slope, temperature, dynamic pressure and air pressure with a mobile device possible to make a universal evaluation, the one described above Solves problems.

The solution to these problems is explained in the following exemplary embodiment.  

The bicycle data recorder is a mobile microprocessor-controlled device with its own power supply from batteries, accumulators and / or solar cells, which is preferably intended for use on bicycles or other muscle-powered vehicles. It consists of the following functional units, which are preferably integrated in a housing: (see FIG. 1).

CPU, Central Processing Unit

The central unit consists of a microcomputer.

Storage

The data and program are stored in electronic memory building blocks of the type RAM, EEPROM or Flash-RAM or a combination of these storage types. The memory can be integrated on the microcomputer board be grilled or realized with separate building blocks.

Clock / time

The internal system clock is preferably used for time and / or timer functions of the microcomputer used. A DCF radio clock module can optionally Provide time signal.

Display

The display is preferably an alphanumeric (optional graphic) LCD display with optional lighting. There is also a display Execution in LED or plasma technology possible.

input box

The input field is designed as a membrane keyboard or with individual buttons. A Multiple assignment of the keys with different functions is possible. The The keyboard assignment is identified by labeling the keyboard door. With a suitable arrangement of keyboard and display, the current key turbo assignment are shown on the display.

PC interface

The PC interface is preferably a serial interface for bidirectional data exchange. The connection to the PC is established preferably made with a cable wireless transmission (e.g. infrared) possible.  

Sensor interface

The sensor interface sets the signals coming from the sensors in for the CPU processable signals around. The shape of the incoming signals can be analog or digital.

Telemetry (transmitter / receiver)

Telemetry allows unidirectional or bidirectional data exchange between the bicycle data recorder and an external telemetry unit (stationary, mobile or another bike data recorder) in online mode (real time).

Any data and parameters can be exchanged and sent via telemetry Evaluation, storage or display can be made available. So that's the Data exchange between two bicycle data recorders possible.

The bike data recorder is connected to sensors, the following sizes can record: distance (route), dynamic pressure, air pressure, temperature, Inclination (angle), cadence and pulse rate.

Exemplary embodiments of sensors are described below, which are described in are able to record the above-mentioned quantities. All sensors deliver electrically evaluable signals.

Displacement sensor

The distance is measured by counting the wheel revolutions and the then multiplying the number of wheel revolutions by the Wheel circumference. An elec is preferably used to detect the wheel revolutions tromagnetic system, with one or more in the front or rear wheel mounted magnets on a reed contact or Hall Pass the sensor without contact and one or more per wheel revolution Generate pulse signals.

Back pressure / true air speed sensor

The dynamic pressure is preferably determined according to the principle of the Pitot tube. The Difference between the total pressure at the stagnation point and the ambient pressure detected with a differential pressure sensor, the signal conversion z. B. piezo resistive is optionally also a version with a hot film Anemometer possible.  

Air pressure sensor

The air pressure is preferably measured using a relative pressure sensor, whose signal conversion z. B. piezoresistive.

Temperature sensor

The temperature sensor is e.g. B. as a temperature-dependent resistor (PTC, NTC), temperature-dependent transistor and / or thermocouple.

Tilt sensor

The inclination sensor is preferably a sensor with a capacitive one Measuring method used, the inclination-related change in a liquid the output signal changes in proportion to the angle.

Cadence sensor

The cadence is determined by normalizing the number of cranks rotations determined on a unit of time. The number of crank revolutions becomes analogous to the detection of the number of wheel revolutions during the distance measurement determined, but the rotating magnet is attached to the crank arm.

Pulse rate sensor

The pulse rate is measured using a commercially available sensor chest strap with wireless signal transmission.

From the input variables recorded, the bicycle data recorder is able to derive among other things the following variables: speed relative to driving Railway (current, maximum, average), route (daily km, total km), Speed relative to the surrounding air (true air speed), headwind speed, acceleration, altitude, altitude difference (current, total), travel time, stopwatch, performance (current, maximum, average), Work done over the distance traveled, incline (degrees, percent).

The bicycle data recorder is like a conventional bicycle computer in the Able to display the captured data on a display. In addition, he can record / save the determined data and send it to an Transfer personal computer (PC). Every new route can be done at home on the PC saved and evaluated. Furthermore, the editing of the recorded data possible, so that artificial march tables are created can.  

A printed representation of the recorded data allows the driver e.g. B. the creation of a detailed personal logbook or the gra fishing Expression of the height profile of a route traveled (route profile, Meters in altitude over the route).

The PC interface allows riding data to be transferred from the PC back to the bike data Store the recorder so that it can be compared with current driving data can be.

Due to the sensors used and the powerful CPU, it is with the Bicycle data recorder possible to perform a performance assessment, which also detects the driving resistance and thus a much more precise measure for the service performed represents as the average speed. Now the performance of any training session can also be performed Compare different routes (flat or mountainous).

The possibility described above, routes already traveled as a reference storing it back in the bike data recorder provides the rider with a March table available to him individually during the training session specifies objective driving data (regardless of his subjective memory).

The driver has a constant comparison option during his training session between the current driving data and the corresponding reference driving data his last training session, which makes sense over the same route has led.

The driver can display comparison values of selected current driving data with the corresponding reference driving data, for example: B. by how many kilometers per hour it is faster or slower than the last time ( Fig. 2). The assignment of the current driving data to the reference driving data is preferably carried out via the number of wheel revolutions (= distance traveled) or the driving time.

By determining its performance and the constant objective The driver can now compare options with reference driving data ability to decide during training whether to increase their performance or diminished, because he can see at any moment whether he is with his mom tan performance exceeds or falls below his training goal.  

Furthermore, the bicycle data recorder offers the possibility, due to the Comparison of the current driving data determined with the reference driving data extrapolate the end of the training session, e.g. B. the expected Total travel time, the estimated arrival time, the estimated through cutting speed or the expected performance.

The telemetry equipment makes it possible to use a mobile or stationary Receiving unit the determined data in online operation z. B. out by PC evaluate. Thus z. B. a trainer for the driver's current driving data Available and can now also be new during training if necessary Make regulations. Medical monitoring of the driver is also carried out (Heart rate) possible.

Another field of application for the telemetry of the bicycle data recorder is Sports reports. It is now possible to update the current driving data, especially with live Broadcasts of sporting events related to bicycles for reporting device (e.g. display of current and reference driving data in the current television picture).

The data exchange between two bicycle data recorders via telemetry allows one out with a bike data recorder during a bike race equipped outliers to take advantage of their current lead (time, distance) compared to a team equipped with a bicycle data recorder display raden in the main field based on the transmitted driving data.  

Advantages of the bicycle data recorder over conventional bicycle Computers or measuring cranks or stationary ergometers.

Capture, evaluate, display and record / save any driving data.
Recording the geometric route profile.
Possibility to transfer the recorded data to a personal computer. Creation of a detailed logbook.
Storage of the driving data of already traveled routes from the personal computer in the bicycle data recorder as a reference driving route (marching table).
Saving of march tables created by hand.
Constant comparison of current driving data with reference driving data stored in the device.
Performance assessment on a real bike.
Simple determination of the relevant parameters for the performance determination in different driver-vehicle combinations by means of a roll-out test.
Determination of air resistance.
Determination of rolling resistance.
Determination of the speed relative to the surrounding air (true air speed).
Determination of the headwind speed.
Possibility of extrapolating driving data to the end of the training session, such as B. the expected total travel time, etc.
Possibility of exchanging any data via transceiver (telemetry) with an identical device or an external mobile or stationary transceiver in online mode.

Theory of performance assessment

An exact determination of the service provided sets the exact knowledge of Driving resistance ahead. The determination of these driving resistances will follow the described.

The following applies to the power P:
Performance = driving resistance _* speed _* efficiency

P = F _{w *} v _* Φ

V represents the speed compared to the road. The factor Φ takes into account the mechanical efficiency of the drive. The driving resistance consists of the following components:
(See Fig. 3)

Driving resistance = air resistance + rolling resistance + gradient resistance + Acceleration resistance

F _w = F _wAir + F _wRoll + F _wSteig + F _wBeschl.

a) Gradient resistance

The following applies to the gradient resistance:

Gradient resistance = mass _* gravitational acceleration _* sin (gradient angle)

F _wsteig = m _* g _* sinα _climb

For an exact determination of the gradient resistance, the Slope of the route also knowledge of the mass of driver and vehicle required. The acceleration due to gravity can be considered approximately constant be tested.  

b) Air resistance

The following applies to air resistance:

Air resistance = air resistance coefficient _* end face _{* back} pressure

F _wair = c _{w *} A _* q

The following applies to the dynamic pressure q:

Back pressure = ½ _* air density _* (relative speed) ²

q = ½ _* rho _* v _rel ².

Here rho = f (temperature; air pressure) and v _rel represents the speed relative to the surrounding air (true air speed). The dynamic pressure can be determined with a corresponding pressure sensor or an air flow sensor.

The value for the air density rho can be determined by measuring the temperature and the Air pressure to be corrected.

The determination of the drag coefficient c _w and the front surface A usually takes place in the wind tunnel. Due to the diversity of the bicycles and riders considered, a wind tunnel test would be required for each driver-vehicle combination. However, these measurements are very complex and expensive and therefore not very practical.

Likewise, the assumption of fixed values for c _w and A for different driver-vehicle combinations would only take insufficient account of the various possible combinations.

A simple and practical determination of c _w and A can be carried out with a rollout test (see below).

c) rolling resistance

The following applies to the rolling resistance:

Rolling resistance = rolling resistance coefficient _* mass _* gravitational acceleration

F _wRoll = f _{r *} m _* g

The rolling resistance F _wRoll can be determined together with the air resistance in a rollout test (see below).

d) acceleration resistance

In contrast to the stationary driving resistances mentioned above, it is acceleration resistance is a transient force. Then she kicks when the driver changes speed, d. H. an acceleration takes place.

The following applies to the acceleration resistance:

Acceleration resistance = mass _* acceleration

F _wDec. = m _* a

The acceleration a can be determined in such a way that at two points in time t₁ and t₂ measures the speeds v₁ and v₂ and the speed that occurs difference δv = v₂ - v₁ divided by the time difference δt = t₂ - t₁.

Therefore:

F _wDec. = m _* δv / δt.

Rollout attempt

The rollout test is used to determine the sizes c _{w *} A and f _r . For this purpose, the driver must accelerate to a predetermined speed. Now it can be rolled out while the time, temperature and air pressure are recorded over the path. The resulting relationship between speed and time is shown in FIG. 4.

The following applies to air and rolling resistance:

F _{wair, roll} = ½ _* c _{w *} A _* rho _* v _rel ² + f _{r *} m _* g

This relationship can be simplified as follows:

F _{wair, roll} = b _* v _rel ² + c

Here correspond to:

b = 1.4 _* c _{w *} A _* rho

and

c = f _{r *} m _* g

From the recorded data, the coefficients b and c can be determined by suitable mathematical operations, which allow the air and rolling resistance to be calculated as a function of the driving speed (F _{wLuft, Roll} = f (v _rel )).

The total travel resistance can now be calculated as a function of the speed v _rel , the gradient-climb and the acceleration δv / δt ( FIG. 5).

F _w = F _{w air, roll} + F _{w climb} + F _{w lock}
F _w = b _* v _rel² + c + m _* g sin α _rise + m _* δv / δt.

The following applies to the service:

P = F _{w *} v _* Φ

Thus, the speed can be used at any time determine the service performed.

The sizes c _{w *} A and f _roll required for the performance determination with the bicycle data recorder are determined with the help of a _roll- out test for the individual driver-vehicle combination.

The mass of driver and vehicle and the mechanical efficiency Φ will entered manually via the input field.

A mathematical function (see above), which shows the current performance depending on Driving speed, dynamic pressure, air pressure, temperature, incline and acceleration inclination calculated.  

Through this measurement, the FDR is able to be at the end of a training session to show performance and work performed. This allows the driver recognize whether he has achieved his performance goal.

Claims (10)

1. Microprocessor-controlled device for muscle-powered vehicles, preferably wise bicycles, hereinafter referred to as bicycle data recorders, for Acquisition, evaluation, display and recording / storage of driving data like, distance, time, cadence, pulse, inclination, air pressure, speed, Daily kilometers, total kilometers, average speed, maximum speed, incline, absolute altitude and cumulative altitude difference. 2. Device according to claim 1, characterized by the determination of the driving speed relative to the surrounding air (true air speed) preferred through the optional detection of the dynamic pressure (pressure sensor) or the air flow (hot film anemometer). 3. Device according to one or both of claims 1 and 2, characterized by the detection of the temperature for the correction of temperature-dependent Parameters (e.g. air density). 4. Device according to one or more of claims 1 to 3, characterized through the possibility of entering the mass of driver and vehicle Power calculation. 5. Device according to one or more of claims 1 to 4, characterized due to the possibility to enter the mechanical efficiency Φ Power calculation. 6. Device according to one or more of claims 1 to 5, characterized by the possibility of determining the sizes c _{w *} A and f _r by means of a roll-out test for performance calculation. 7. Device according to one or more of claims 1 to 6, characterized through the possibility of calculating and displaying the vomited by the driver or performance to be provided by determining the driving resistance composed of rolling resistance, air resistance, gradient resistance and acceleration resistance. 8. Device according to one or more of claims 1 to 7, characterized through the possibility of exchanging any data with a staff Computer.   9. Device according to one or more of claims 1 to 8, characterized through the possibility of exchanging any data by sending Receiver unit (telemetry) with an identical device or an external NEN mobile or stationary transceiver. 10. Device according to one or more of claims 1 to 9, characterized through the possibility of currently determined driving data on the number of Wheel revolutions (= distance traveled) or over the travel time in the device assign stored data records from previous routes and these during and / or after a journey to evaluate and ver same.