Electronically controlled mechanical resistance device for rowing machines

Abstract

This invention offers a rowing machines' mechanical resistance device which comprises an electric motor and a programmable control. While it simulates the beneficial responses of a mechanical resistance imparting device comprising a fluid pump and a flywheel, it simultaneously eliminates the compromising effect of backlash. Said backlash exists on commonly used, state of the art rowing machines between the idling and the pulling phases of a rowing stroke. By eliminating backlash, this invention allows rowers to achieve better rowing form and avoid injury.

Description

FIELD OF THE INVENTION

[0001] The invention relates to the field of exercise equipment and more specifically to improvements to rowing machines.

BACKGROUND

[0002] All state-of-the-art rowing machines, including static and dynamic, have been known to facilitate the simulation of an oarsmen's motions, similar to ones found in moving rowing shells. An example of a static rowing machine can be found in U.S. Pat. No. 4,396,188, and an example of a dynamic machine can be found in U.S. Pat. No. 5,382,210. Both static and dynamic rowing devices commonly used by serious rowers deploy a mechanical resistance device comprising a flywheel and an adjustable fluid pump. The flywheel's inertia simulates a boat's linear inertia, whereas the resistance imparted largely by the fluid pump simulates an oar blade being dragged through the water.

[0003] The comparable and beneficial effect related to deploying flywheels on rowing machines and other exercise devices occurs as a result of the user's net energy, which is absorbed by the flywheels on any one of these devices. The resulting flywheel motion provides the user with feedback from a moving system. For example, on a rowing machine, the feedback felt by the rower simulates boat motion. On a stationary bicycle, the feedback simulates motion felt while on a non stationary bicycle, etc.

[0004] The problem associated with using flywheels on rowing machines is related to their one directional motion. On most other exercise devices, the combined forces involved in producing exercise motion tend to be predominantly aligned with the moving flywheel. For example, peddling an exercise bicycle involves moving the feet in a circular motion in one direction. This motion is synchronous and aligned to the moving flywheel. On rowing machines, a rowing stroke comprises two parts; the idling and the power portion. The rower's combined motion during the idling phase is counter to the motion of the moving flywheel, whereas the combined motion during the power phase is synchronous and aligned to it.

[0005] In order for a user to disengage or decouple from the flywheel, both rowing machines and other exercise devices deploy one way clutches or ratchets. To re-engage the flywheel, a cyclist may only have to synchronize to it once during a practice. In contrast, a rower has to catch up to the moving flywheel at the beginning of the power phase of every stroke during a practice. Furthermore, in order to catch up to the flywheel, a cyclist may use her legs only, whereas a rower must use the entire body. Moving one's legs is certainly a less difficult task than moving one's entire body.

[0006] On state of the art rowing machines, reconnecting with the moving flywheel becomes more difficult as the flywheel moves faster during more intensive exercise. In an effort to catch up to the flywheel, rowers tend to jerk their shoulders and forearms. The additional shoulder and forearm movement is not ideal since this motion is contrary to what should be used when rowing real boats. Ultimately, the tendency to use the shoulders and the forearms during the initial portion of the power phase of a rowing stroke results in an ineffective rowing form and can cause injury.

[0007] To eliminate the drawbacks of a flywheel, it is imperative that it is completely eliminated from rowing machines. In order to retain the flywheel's benefits however, it is best to replace its useful effects with those produced by alternative devices and methods. To that end, this invention focuses on replacing not just the flywheel, but the combination of the flywheel and a fluid pump with an electric motor and its control means.

[0008] The result of replacing the flywheel and the adjustable pump mechanism with this invention completely eliminates the need for rowers to catch up to the moving flywheel at the beginning of the power phase of every stroke. This will eliminate the need for rowers to over compensate their motion with the unnecessary and ineffective shoulder and forearm movement. Consequently, by implementing this invention on current and new rowing machines, coaches and rowers will significantly diminish the risk of any motion related injuries.

SUMMARY OF THE INVENTION

[0009] The primary goal of this invention is to eliminate the backlash that exists when exercising on state of the art rowing machines. This backlash is present between the idling and the pulling phases of a rowing stroke and occurs on any common rowing machine that comprises a flywheel. It is hoped that this invention is used to substitute the flywheel and a mechanical resistance means with a device comprising an electric motor and a programmable control means.

[0010] This invention simulates the behavior of a mechanical resistance device comprising a flywheel and a fluid pump. The major benefits of the currently used mechanical devices are retained by reproducing their valuable responses. Importantly, the ability to program the responses from the new system allows for the removal of the drawbacks inherent in the state of the art technology. The substitution of a purely mechanical device with a microprocessor controlled device also provides additional benefits, such as programmable workout modes.

[0011] By eliminating the backlash occurring on commonly used rowing machines, this invention allows the rowers to execute stress free rowing strokes. Stress free rowing leads to achieving better rowing technique which then translates to faster moving boats. More importantly, better rowing technique contributes to significantly reducing the potential for rowers to sustain motion related injuries.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 shows an example of prior art device.

[0013] FIG. 2 shows a system comprising an example of prior art device coupled to a DC motor. This system is used to establish the drag coefficient of the prior art device. Further details are disclosed in the Detailed Description of the Preferred Embodiments.

[0014] FIG. 3 shows an embodiment of this invention.

[0015] FIG. 4 shows the algorithm table used in the preferred embodiment of this invention.

[0016] FIG. 5 shows the basic functional components of this invention. Further details are disclosed in the Detailed Description of the Preferred Embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] This invention is intended to replace a common mechanical resistance device that comprises a flywheel. An example of such device is shown in FIG. 1, where system 1 is an air pump, and said pump comprises a flywheel 6, impelling vanes 3, a safety shroud 5, and an air intake valve 4.

[0018] An embodiment of this invention is shown in FIG. 3. It comprises a motor 8, a transmission means 10, an optional one way clutch 11 and a microprocessor driven motor control means 9. FIG. 3 also depicts an electrical cord 13, connecting said motor control means to said motor, the motor mounting brackets 12, and a controller wire harness 14. Said harness comprises component wires used to connect said controller to sensors and an auxiliary computer (all not shown in FIG. 3.)

[0019] For the purpose of this discussion, the subsequent paragraphs will refer to a common state of the art system, (similar to the system illustrated in FIG. 1) as the old device (OD) and the embodiments of this invention (similar to the system illustrated in FIG. 3) shall be referred to as the new device (ND).

[0020] The ND's general function is to simulate the power responses to those of the OD. However, the simulation of said responses is omitted for the initial piece of a rowing stroke's power phase, in order to avoid the adverse effect of backlash. Said backlash is present between the idling and the pulling phases of a rowing stroke and occurs on any OD that comprises a flywheel.

[0021] Generally, in order to simulate the power response of an OD, it is imperative to include all of its power response components. In examining prior art, it is known that the power response of an OD can be written as the sum of the power response related to drag and the power response related to inertia (P.sub.combinedOld=P.sub.dragOld+P.sub.inertiaOld). If a ND is to simulate the OD's power responses, the ND shall have identical power responses to that of the OD, where P.sub.dragOld=P.sub.dragNew and P.sub.inertiaOld=P.sub.inertiaNew.

[0022] A ND shall be sized such that when drivingly coupling either the ND or the OD via their respective transmission means to the user's handle, the torque response of the ND shall be identical to that of the OD. More precisely, the torque response of the ND shall be equal to that of the OD multiplied by a torque multiplier (T.sub.multiplier), where T.sub.multiplier represents the ratio between the gear ratios of the ND's and the OD's transmission means. If the gear ratio of the ND's transmission means is identical to that of the OD, T.sub.multiplier is equal to 1. Otherwise, T.sub.multiplier is either greater than or a fraction of 1. The details of sizing the ND are omitted, as a similar procedure can be accomplished by those skilled in the art of mechanical or electrical engineering.

[0023] Similar to the relationship between the torque responses of the two devices, the relationship between the angular velocities of the two devices' rotating components is also related to the same torque multiplier (T.sub.multiplier.) The angular velocity of the ND's rotating parts (.omega..sub.new) shall be determined from the angular velocity of the OD's rotating parts (.omega..sub.old) divided by T.sub.multiplier. Or, the angular velocity of the OD's rotating parts (.omega..sub.old) shall be determined by the angular velocity of the ND's rotating parts (.omega..sub.new) multiplied by T.sub.multiplier.

[0024] The power response of the OD related to drag (P.sub.dragOld) can be obtained by determining the OD's drag coefficient (Kn) and the angular velocity of its rotating parts (.omega..sub.old), where the equation for obtaining said power response is P.sub.dragOld=Kn*.omega..sub.old.sup.3. The details of establishing said equation are known from examining prior art. Since .omega..sub.old is also equal to the product of said torque multiplier (T.sub.multiplier) and the angular velocity of the ND's rotating parts (.omega..sub.new), .omega..sub.old can be determined by obtaining .omega..sub.new via measurements. Unlike obtaining .omega..sub.old, which can be accomplished by known means, obtaining the drag coefficient factor Kn is not obvious. Hence, a similar procedure is discussed hereafter.

[0025] A drag coefficient Kn is related to the air intake valve 4 (FIG. 2) openings. An example is shown in FIG. 2 where hole A10, belonging to valve 4, is aligned with the locking pin 7. At that setting, valve 4 causes the OD to consume the least amount of air and the drag coefficient factor (Kn) is denoted as K10. Similarly, in FIG. 1, pin 7 is aligned with hole A5. At that setting, valve 4 causes the OD to consume the most amount of air, and Kn is denoted as K5. In examining the setting related to K10 in FIG. 2, and considering said equation showing the drag related power effect (P.sub.dragOld=Kn* .omega..sub.old.sup.3), K10 can be calculated from K10=P.sub.dragOldK10/.omega..sub.old.sup.3, where P.sub.dragOldK10 is the power consumed by the air drag at setting related to K10. Hence, for a given OD's angular velocity of its rotating parts (.omega..sub.old), the drag coefficient factor K10 can be established by measuring P.sub.dragOldK10.

[0026] To measure P.sub.dragOldK10, the OD (FIG. 2) is coupled to a DC motor 2 and its controller (not shown) comprising known means. By driving the DC motor, the overall system, which comprises the OD and the DC motor, is set to a steady arbitrary rotational speed (.omega..sub.test), where .omega..sub.old=.omega..sub.test. The requirement at .omega..sub.test is that the voltage supplied to the DC motor is greater than the nominal voltage of the DC motor for .omega..sub.test under no load. At .omega..sub.test, the power response of the OD related to K10 is equal to its measured power response (P.sub.dragOldK10=P.sub.dragTest), where P.sub.dragTest is equal to the product of the DC motor's measured voltage (V.sub.test) and the DC motor's measured current (I.sub.test). For the purpose of this discussion, all relatively negligible inefficiencies of the DC motor and its controller are omitted. Once P.sub.dragOldK10 and .omega..sub.test are known, K10 is easily calculated using the above indicated equation K10=P.sub.dragOldK10/.omega..sub.old.sup.3. A similar procedure can be used to establish any other air drag coefficient (Kn), corresponding to any air intake valve 4 setting A1-10 (FIG. 1 or FIG. 2). Although it is possible to establish an almost infinite number of air drag coefficient factors ranging from K1 to Kn, in developing the embodiments of this invention, there were ten discreet Kn factors considered. Said ten Kn factors correspond to ten discrete air intake valve 4 openings spread across the full valve 4 openings range.

[0027] From examining prior art, the power response of the OD related to inertial effect of its rotating parts is given by P.sub.inertiaOld=.omega..sub.old*J.sub.old*(d.omega..sub.old/dt), where J.sub.old is the angular moment of inertia, d.omega..sub.old/dt is the angular acceleration and .omega..sub.old is the angular velocity of the OD's rotating parts. Similarly, the equation representing the power response of the ND related to inertial effect of its rotating parts is given by P.sub.inertiaNew=.omega..sub.new*J.sub.new*(d.omega..sub.new/dt)- . By merging both equations, the power response of the OD related to inertial effect of its rotating parts is given by P.sub.inertiaOld=P.sub.inertiaNew+.omega..sub.old* (J.sub.old-J.sub.new/T.sub.multiplier.sup.2)*(d.omega..sub.old/dt), where .omega..sub.new=.omega..sub.old/T.sub.multiplier (shown above). In said equation, J.sub.new represents the angular moment of inertia of the ND's rotating parts, which comprises the motor's rotor. This equation also shows that the power response of an OD related to inertial effect of its rotating parts (P.sub.inertiaOld) comprises the physically existing component (P.sub.inertiaNew) and the virtual component .omega..sub.old*(J.sub.old-J.sub.new/T.sub.multiplier.sup.2)*(d.omega..su- b.old/dt). When simulating the inertia related power response of the OD, P.sub.inertiaNew should be omitted from calculations (because it represents a physically existing component). It is also important to observe that the real inertial effect related to the ND (P.sub.inertiaNew) should only be considered when a rower is drivingly engaged to the ND, during the power phase of a stroke. Calculating the above listed equation requires obtaining J.sub.old and J.sub.new, which can be accomplished by known means. The angular velocity .omega..sub.old and also the angular acceleration d.omega..sub.old/dt of the OD's rotating parts, as discussed in previous paragraphs of this section can be calculated from the angular velocity of the ND's motor rotor (.omega..sub.new) and torque multiplier T.sub.multiplier.

[0028] A rower's overall power response while drivingly engaged to the ND, during the power phase of a rowing stroke, can be summarized by P.sub.rower=P.sub.combinedNew=P.sub.combinedOld. According to shown equations, the combined calculated power of the ND is P.sub.combinedNew=P.sub.rower=P.sub.dragOld+P.sub.inertiaOld=Kn*.omega..s- ub.old.sup.3+P.sub.inertiaNew+.omega..sub.old*(J.sub.old-J.sub.new/T.sub.m- ultiplier.sup.2)*(d.omega..sub.old/dt). As stated in the previous paragraph, the simulated combined power response of the OD during the power phase of a rowing stroke is calculated after discounting the real inertial power effect of the ND. The resulting equation is P.sub.combinedOldSimulatedPower=Kn*.omega..sub.old.sup.3+.omega..sub.old*- (J.sub.old-J.sub.new/T.sub.multiplier.sup.2)*(d.omega..sub.old/dt). In the claims section, as well as in FIG. 4 of this application, P.sub.combinedOldSimulatedPower is shown as P.sub.strokePower, where P.sub.combinedOldSimulatedPower=P.sub.strokePower.

[0029] When considering the idling portion of a rowing stroke, it is important to discuss relevant observations before introducing any mathematical representation of a simulated power response of the OD. As is the case during said portion of a stroke when rowing on a prior art device, a rower is completely decoupled from the OD. This decoupling is usually accomplished via the use of a one way clutch and the total power input of a rower to the OD due to said decoupling is zero (P.sub.rower=0). Therefore, if a ND is to simulate the OD, the assumption of P.sub.rower=0 should also exist for the ND. This assumption is made whether or not a rower is drivingly engaged to the ND (during the idle phase of a stroke.) If the ND's transmission means 10 (FIG. 3) comprises a one way clutch 11, during the idling portion of a rowing stroke, a rower is not drivingly engaged to the ND. Alternatively, if a one way clutch is absent, a rower would be drivingly engaged. Ultimately, throughout the idling portion of a rowing stroke, the simulation of the OD has to account for the full inertial effect related to the OD's rotating parts only.

[0030] In light of the information presented above, the combined simulated power of the OD during the idling phase of a rowing stroke can be summarized with P.sub.combinedOldSimulatedIdle=Kn*.omega..sub.old.sup.3+.omega..sub.old*J- .sub.old*(d.omega..sub.old/dt)=P.sub.rower=0. The equation is used to derive the simulated instantaneous rotational velocity of the OD's rotating parts (.omega..sub.old). It is transformed to .omega..sub.old=Kn*.omega..sub.old.sup.2*dt/J.sub.old, where dt represents the duration of the ND's calculating algorithm and d.omega..sub.old represents the negative change of the simulated OD's rotating components' angular velocity (.omega..sub.old), over said interval (dt). Coincidentally, obtaining d.omega..sub.old and .omega..sub.old from the same equation applies in any other case where a rower is not drivingly engaged to the ND. For example, during the final portion of the power phase of a rowing stroke, a rower may decide to stop pulling half way through the stroke, for whatever reason. To determine if a rower is engaged drivingly, during this portion of a stroke, .omega..sub.old shall be tracked not only by using said .omega..sub.new*T.sub.multiplier, but also using said d.omega..sub.old=Kn*.omega..sub.old.sup.2* dt/J.sub.old. For a given interval dt, if (.omega..sub.new*T.sub.multiplier)>=(.omega..sub.old-d.omega..sub.old)- , a rower is engaged drivingly. Similarly, if (.omega..sub.new*T.sub.multiplier)<(.omega..sub.old-d.omega..sub.old), a rower is not engaged drivingly to the ND. When a rower is not drivingly engaged, the power response of the ND shall be zero. This condition is shown as P.sub.strokePower=0 in both FIG. 4 and the claims section.

[0031] In addition to the idle and the final portion of the power phase of a rowing stroke, it is also important to consider the initial portion of the power phase of a stroke. To avoid the major drawback inherent in the ODs, where rowers have to work to "chase" the moving flywheel, the ND shall completely stop said motor 8 (FIG. 3) at the point where there is a dead stop between the idle and the power phase of a rowing stroke. By stopping the motor, the ND shall synchronize its motion to that of the rower's body. In this document, the case of rowers "chasing" the OD's flywheel from said dead stop is also referred to as the OD's backlash. In addition to stopping said motor at the instance of said stop, the ND's algorithm shall cause the same motor to provide substantial torque, countering the rower's pull. This torque will allow a rower to immediately engage the device without having to execute any sudden motion.

[0032] Halting the ND's motor at the dead stop between the idle and the power phases of a rowing stroke also causes the ND to lose any motion feedback. Regardless, the algorithm should still maintain a simulated angular velocity .omega..sub.old of the OD's rotating parts by calculating said equation d.omega..sub.old=Kn*.omega..sub.old.sup.2*dt/J.sub.old, every said interval dt.

[0033] As a rower becomes drivingly engaged to the ND (immediately following the instance of the dead stop between the end of the idling and the beginning of the power phase of a rowing stroke), the simulated power response algorithm should be said P.sub.strokePower=Kn*.omega..sub.old.sup.3+.omega..sub.old*(J.sub.old-J.s- ub.new/T.sub.multiplier.sup.2)*(d.omega..sub.old/dt). However, since at that stop, the ND's real .omega..sub.new is purposely set to 0 and .omega..sub.old=.omega..sub.new*T.sub.multiplier, using P.sub.strokePower=Kn*.omega..sub.old.sup.3+.omega..sub.old*(J.sub.old-J.s- ub.new/T.sub.multiplier.sup.2)*(d.omega..sub.old/dt) would result in the simulated power response of 0. Instead, as indicated above, the power response of the ND is set to produce a substantial torque response. To help resynchronize the ND's .omega..sub.new*T.sub.multiplier with that of the simulated .omega..sub.old of the OD, the algorithm shall decrease the power responses of the ND over a few intervals dt. As long as the calculated .omega..sub.old remains less than .omega..sub.new*T.sub.multiplier (obtained via measurements), the power response values of the ND should keep diminishing from a maximum set at said dead stop.

[0034] The following equation is introduced to smoothly transition between a maximum power setting at said dead stop and the point where .omega..sub.old obtained from d.omega..sub.old=Kn*.omega..sub.old.sup.2*dt/J.sub.old is equal to .omega..sub.old obtained from measurements, (.omega..sub.old-d.omega..sub.old)==(.omega..sub.new*T.sub.multiplier):

P.sub.beginStroke=C*(P.sub.max*((.omega..sub.old-d.omega..sub.old)-.omeg- a..sub.new*T.sub.multiplier)/(.omega..sub.old-d.omega..sub.old)+P.sub.stro- kePower*(1-((.omega..sub.old-d.omega..sub.old)-.omega..sub.new*T.sub.multi- plier)/(.omega..sub.old-d.omega..sub.old))).

[0035] In said equation, P.sub.beginStroke is the power response of the ND during the initial portion of the power phase of a rowing stroke. P.sub.max is the maximum power response of the ND and P.sub.strokePower is the calculated power obtained from P.sub.strokePower=Kn*.omega..sub.old.sup.3+.omega..sub.old*(J.sub.old-J.s- ub.new/T.sub.multipher.sup.2)*(d.omega..sub.old/dt) (equation mentioned above). Term ((.omega..sub.old-d.omega..sub.old)-.omega..sub.new*T.sub.multiplier)/(.o- mega..sub.old-d.omega..sub.old) is used for percent biasing, where if for example .omega..sub.new is equal to zero, this term yields 1 (100%). If (.omega..sub.old-d.omega..sub.old) ==(.omega..sub.new*T.sub.multiplier), the term yields 0 (0%), etc. At said dead stop, since .omega..sub.new is equal to 0, P.sub.beginStroke=C*P.sub.max, and at the point where (.omega..sub.old-d.omega..sub.old)==(.omega..sub.new*T.sub.multiplier), P.sub.beginStroke=C* P.sub.strokePower. The value C represents a catch factor and should range between 0.1 and 1. Higher C values translate to harder power/torque responses of the ND and vice versa. The catch factor should help simulate different oar riggings and as such, it should be selectable by the rowers. Selecting smaller C values will provide rowers a sensation of rowing with a lighter rigged oar and vice versa.

[0036] From the point of the power phase of a rowing stroke where the simulated angular velocity of the OD's rotating parts (.omega..sub.old) becomes first equal and then less than the product .omega..sub.new*T.sub.multiplier, and toward the end of the power phase of a stroke, the algorithm to provide the power responses to rowers is P.sub.strokePower=Kn*.omega..sub.old.sup.3+.omega..sub.old*(J.sub.old-J.s- ub.new/.sub.multiplier.sup.2)*(d.omega..sub.old/dt) (equation shown above). This equation is valid as long as the condition (.omega..sub.new*T.sub.multiplier)>=(.omega..sub.old-d.omega..sub.old) is satisfied, where d.omega..sub.old=Kn*.omega..sub.old.sup.2*dt/J.sub.old(shown above). If (.omega..sub.new*T.sub.multiplier)<(.omega..sub.old-d.omega..sub.old), the response of the ND should be set to 0 (P.sub.strokePower=0). The P.sub.strokePower=0 case is relevant if the ND's transmission means does not comprise a one way clutch, in which case it becomes necessary to simulate the condition where the rower disengages from the system drivingly ((.omega..sub.new*T.sub.multiplier)<(.omega..sub.old-d.omega- ..sub.old)). However, if the ND comprises a one way clutch, setting P.sub.strokePower=0 would not be necessary, as said clutch would provide the torque disengagement to the rower.

[0037] FIG. 4 shows a table summarizing the three discussed portions of a rowing stroke and their respective algorithms. It also lists whether or not it is necessary to obtain .omega..sub.new in order to implement said algorithms. Finally, it shows the effects on a rower produced by deploying said algorithms. For example, for the final piece of the power portion of a rowing stroke, the summary table shows that the implemented algorithm comprises equation P.sub.strokePower=Kn*.omega..sub.old.sup.3+.omega..sub.old*(J.sub.old-J.s- ub.new/T.sub.multiplier.sup.2)*(d.omega..sub.old/dt), as long as the condition (.omega..sub.new*T.sub.multiplier)>=(.omega..sub.old-d.omega- ..sub.old) is met. Simultaneously, d.omega..sub.old is calculated from d.omega..sub.old=Kn*.omega..sub.old.sup.2*dt/J.sub.old. In case that (.omega..sub.new* T.sub.multiplier)<(.omega..sub.old-d.omega..sub.old), power to the motor/rower is set to 0 (P.sub.strokePower=0). In addition, the table shows that during the same phase of a stroke, in order to calculate said equations, it is required to obtain the measured rotational velocity of the ND's rotating parts (.omega..sub.new). Finally, for that same portion of a stroke, the table shows that the effect of the algorithm on the ND's motor, and henceforth the rower, is the power setting P.sub.strokePower.

[0038] FIG. 5 shows the basic functional components of this invention's preferred embodiment. The management of the motor via the use of algorithms is accomplished by said motor control means 9 comprising a microprocessor 15, where said microprocessor shall obtain the signals from the attached sensors 16, and process said signals to obtain the parameters necessary to calculate said algorithms. Calculating parameters from sensors 16, as well as running algorithm equations, shall occur every said interval dt. The sensors 16 should comprise said motor's shaft position sensors 16a and at least one sensor providing signals related to the handle of the rowing machine 16b. Using the motor's shaft position sensor's signals, and said interval dt, the microprocessor shall calculate the angular velocity of said motor rotor (.omega..sub.new). The same signals should also be used to establish a rowing stroke's phase and position. In a situation where said transmission means 10 (FIG. 3) comprises a one way clutch 11, establishing a stroke's phase and position will also require using the handle position signals 16b (FIG. 5). Said handle position signals should also be used to determine that the idle and the power phases of a rowing stroke are not mistaken for one another. If a ND's transmission means 10 (FIG. 3) comprises a one clutch 11, both set of sensors (16a and 16b) shall be used to establish a tension map of the rowing machine's cord retracting device. If said clutch is absent, accomplishing a similar task would require only the motor shaft position sensor signals 16a (FIG. 5). Said tension map of said retracting means shall be included when calculating rower's power consumption.

[0039] The motor control means 9 (FIG. 5) also comprises a switching means 17 that shall selectively connect the motor 8 to either the means for managing said motor's resistance to rotation 18, or the means for collecting and storing electric charge 19, or an optional means for drivingly engaging the motor 15. During the power phase of a rowing stroke, said switching means 17 should alternate between connecting the motor windings 8a to the means for managing said motor's resistance to rotation 18 and the means for collecting and storing electric charge 19. During the idle phase of a rowing stroke, said switching means 17 could optionally engage said motor windings 8a to the means for drivingly engaging the motor 15.

[0040] Finally, said motor control means 9 (FIG. 5) also comprises a means to connect said microprocessor to an auxiliary computer 20. Said computer shall obtain data related to all discussed algorithms from the microprocessor 10, and shall calculate various workout display parameters from said data, such as rower's power consumption, traversed distance etc. Furthermore, the auxiliary computer 21 shall also set input parameters to the microprocessor 10, such as said drag coefficient Kn or said catch factor C. Alternating drag coefficient Kn shall simulate various conditions experienced in rowing boats, e.g. rowing upstream, or rowing along tail wind etc. Alternating catch factor C shall simulate lighter versus heavier boat's oar riggings.

[0041] The harnessed energy obtained from the motor windings 8a (FIG. 5), and stored by the means for collecting and storing electric charge 19, shall be used to charge or power the motor control means 9, as well as the auxiliary computer 21.

Claims

1. A device for a rowing machine which provides mechanical resistance comprising: an electric motor; a motor control means comprising a means for managing said motor's resistance to rotation and a microprocessor, wherein said microprocessor's programmed algorithm causes said motor to produce the mechanical responses of a simulated device comprising a flywheel and an adjustable fluid pump; a plurality of motion sensors attached to said motor control means, wherein said sensors detect the position of said motor's shaft and the position of the rowing machine's handle to which an embodiment of this invention is attached to; and a transmission means, wherein said transmission means drivingly engage said motor to said rowing machine's user's handle.

2. A unit, according to claim 1, wherein said motor control means further comprises: a means for collecting and storing electric charge induced in said motor windings, wherein collected charge is used to power said motor control means, and power or charge at least one more auxiliary power draining device; a means to connect said microprocessor to another computer; a means for charging said computer using said collected charge; and a switching means, wherein said switching means selectively engage said motor with said means for managing said motor's resistance to rotation and said means to collect and store electric charge.

3. A unit, according to claim 2, wherein said motor control means stops said motor at the instance of the dead stop between the idling and the power phase of a rowing stroke.

4. A unit, according to claim 3, wherein said microprocessor's programmed algorithm comprises: an algorithm simulating said simulated device during the idling phase of a rowing stroke; an algorithm simulating said simulated device during the initial piece of a rowing stroke's power phase; an algorithm simulating said simulated device during the final piece of a rowing stroke's power phase.

5. A unit, according to claim 4, wherein said fluid is air, and wherein said flywheel and said adjustable fluid pump comprising said simulated device are assumed to rotate in unison.

6. A unit, according to claim 5, wherein said microprocessor's programmed algorithm related to said idling phase of a rowing stroke is d.omega..sub.old=Kn*.omega..sub.old.sup.2*dt/J.sub.old, wherein: said d.omega..sub.old represents the drop of said simulated device's rotating components' angular velocity; said dt represents the interval between said microprocessor's calculations, ranging from 0.1 to 200 milliseconds; said J.sub.old represents the angular moment of inertia of said simulated device's rotating components; said Kn represents the drag coefficient related to said air pump's adjustable air flow settings; and said .omega..sub.old represents the angular velocity of said simulated device's rotating components.

7. A unit, according to claim 6, wherein said microprocessor's algorithm related to said initial piece of a rowing stroke's power phase comprises: an equation, d.omega..sub.old=Kn*.omega..sub.old.sup.2*dt/J.sub.old; a condition, (.omega..sub.old-d.omega..sub.old)>(.omega..sub.new*T.sub.multiplier), wherein: said .omega..sub.new represents the angular velocity of said motor's shaft, and .omega..sub.new is derived from measurements related to said motor's shaft position sensors; said T.sub.multiplier represents a torque multiplier related to the gearing ratio in said transmission means; an equation, P.sub.strokePower=Kn*.omega..sub.old.sup.3+.omega..sub.old*(J.sub.old-J.s- ub.new/T.sub.multiplier.sup.2)*(d.omega..sub.old/dt), wherein: said P.sub.strokePower represents the calculated power response of said simulated device corresponding to said .omega..sub.old; said hew represents the angular moment of inertia of said motor's rotor; an equation, P.sub.beginStroke=C*(P.sub.max*((.omega..sub.old-d.omega..sub.o- ld)-.omega..sub.new*T.sub.multiplier)/(.omega..sub.old-d.omega..sub.old)+P- .sub.strokePower*(1-((.omega..sub.old-d.omega..sub.old)-.omega..sub.new*T.- sub.multiplier) (.omega..sub.old-d.omega..sub.old))), wherein: said P.sub.beginStroke represents the actual power response implemented on said motor; said P.sub.max represents the maximum power response of an embodiment of this invention; said C represents a catch factor ranging from 0.1 to 1, and wherein C shall be used to simulate lighter or heavier boat's oar riggings; and a condition, P.sub.beginStroke<P.sub.strokePower, wherein: if said condition is satisfied, the algorithm shall override any other related equations from this claim and set P.sub.beginStroke according to P.sub.beginStroke=P.sub.strokePower.

8. A unit, according to claim 7, wherein said microprocessor's algorithm related to said final piece of a rowing stroke's power phase comprises: an equation, d.omega..sub.old=Kn*.omega..sub.old.sup.2*dt/J.sub.old; a condition, (.omega..sub.new*T.sub.multiplier)>=(.omega..sub.old-d.omega..sub.old)- , wherein: if said condition is satisfied, .omega..sub.old in subsequent equation shall be calculated according to .omega..sub.old=.omega..sub.new*T.sub.multiplier; an equation, P.sub.strokePower=Kn*.omega..sub.old.sup.3+.omega..sub.old*(J.sub.old-J.s- ub.new/T.sub.multiplier.sup.2)*(d.omega..sub.old/dt); and a condition, (.omega..sub.new*T.sub.multiplier)<(.omega..sub.old-d.omega..sub.old), wherein: if said condition is satisfied, the algorithm shall override any other related equations from this claim and set P.sub.strokePower according to P.sub.strokePower=0;

9. A unit, according to claim 8, wherein said Kn drag coefficient value changes during exercise, wherein said Kn drag coefficient values relate to simulating different wind and water stream speed conditions when rowing real boats.

10. A unit, according to claim 9, wherein said microprocessor's algorithm related to the final piece of a rowing stroke's power phase alternates between the algorithm described in claim 8 and an algorithm causing said motor to produce a constant torque response, wherein said motor's constant torque response is related to simulating light weight lifting.

11. A unit, according to claim 3, wherein for the purpose of calibrating an embodiment of this invention, via using said means for managing said motor's resistance to rotation, said motor control means controllably releases tension between said motor and a retracting cord comprising a rowing machine to which said embodiment of this invention is attached to, wherein: said controllable release of tension is used to establish a tension map of said retracting cord; and said tension map is used to augment calculations related to rower's power consumption when rowing on said rowing machine.

12. A unit, according to claim 3, wherein said motor control means further comprises a means to control said motor drivingly.

13. A unit, according to claim 12, wherein means to control said motor drivingly engage said motor during the idle phase of a rowing stroke.

14. A unit, according to claim 3, wherein said transmission means comprises a one way clutch.

15. A unit, according to claim 3, wherein the method of said means for managing said motor's resistance to rotation is to controllably short said motor windings.