Exercise mode for a personal transporter device

A personal transporter device and corresponding method of operation are given that utilize an exercise mode. A transporter assembly includes a platform, a ground-contacting module, and a motorized drive. The platform supports a user. The ground-contacting module is connected to the platform. The motorized drive powers the ground-contacting module to drive the assembly in a selected direction over an underlying surface. A controller is coupled to and controlling the motorized drive, and also has an exercise mode for opposing a user-provided human power input with a selected level of resistance. When the device is a dynamically stabilized transporter, the controller also controls the motorized drive so as to dynamically stabilize the transporter assembly.

FIELD OF THE INVENTION

The invention generally relates to operating modes for a personal transporter device.

BACKGROUND ART

A “dynamically stabilized transporter,” as used here refers to a personal transportation device having a control system that actively maintains the device's stability while the device is in operation. Transporters of this type are described, for example, in U.S. Pat. Nos. 6,288,505 and 6,302,230, the contents of which are incorporated herein by reference. As used herein, the term “dynamically stabilized” refers to a requirement that, absent active control of the device during operation, the device is unstable with respect to fore and aft tipping when it is in an operating position.

A dynamically stabilized transporter is typically highly responsive to user inputs, so that normal operation may require only relatively minor physical motion from a user. Thus, a period of prolonged operation may represent for the user a lengthy time of relatively little physical activity.

SUMMARY OF THE INVENTION

Embodiments of the present invention include personal transporters and corresponding methods of operation that utilize an exercise mode. A transporter assembly includes a platform, a ground-contacting module, and a motorized drive. The platform supports a user. The ground-contacting module is connected to the platform. The motorized drive powers the ground-contacting module to drive the assembly in a selected direction over an underlying surface. A controller is coupled to and controlling the motorized drive, and also has an exercise mode for opposing a user-provided human power input with a selected level of resistance, whether in a dynamically balanced condition or otherwise.

In a further embodiment, the personal transporter device may be a dynamically stabilized transporter, and the controller may further control the motorized drive so as to dynamically stabilize the transporter assembly. In addition or alternatively, the exercise mode may allow the user to provide the human power input by causing movement of the transporter assembly relative to the underlying surface. For example, the user may push or pull from the underlying surface against the transporter assembly. Or the user on the platform may move the transporter assembly alternately in opposing directions so that the transporter assembly maintains a relatively fixed position on the underlying surface. In such an embodiment, the relatively fixed position may be maintained by the controller using a position term variable, a pitch damping term variable, and/or a wheel damping term variable.

The personal transporter device may be operated in a current mode or in a voltage mode. The human power input may be required to be a specified function of the speed of the assembly over the underlying surface, such as the square or other power of the speed. In certain modes, the human power input may act to recharge a transporter device power source. In addition or alternatively, the personal transporter device may convert the human power input into heat. For example, the motorized drive may oppose the human power input, or a component, such as a resistor, may dissipate the heat.

A user seat may be connected to the platform, and a pedal arrangement provided for a seated user to provide the human power input. A user display may provide to the user an indication of at least one of a present state of a transporter device power source, a rate of change of the present state of the power source, a total amount of calories expended by the user, and a present rate of calories being expended by the user.

An embodiment may include a coupling mechanism for coupling the transporter assembly to a separate exercise device. Then, operation of the controller in exercise mode involves opposing a user-provided human power input to the separate exercise device with a selected level of resistance provided by the motorized drive of the personal transporter.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Representative embodiments of the present invention include a personal transporter device and a method of operating such a transporter that includes at least one exercise mode, which allows a user to work against a selected level of resistance provided by the device. Periodic operation in exercise mode may provide the user with a change in travel experience while providing a cardiovascular challenge that may advantageously improve cardiovascular fitness of the user. In addition, in some modes, the work performed by the user may be reconverted into an energy input for the power source of the transporter, acting to recharge the power source.

FIG. 1shows an embodiment of a dynamically stabilized transporter18to which the present invention may be applied. Dynamically stabilized transporters are manufactured and marketed by Segway LLC of Manchester, N.H. As to the transporter18, a user10stands on a support platform12, holding hand grip14, which is connected to the platform by a handle16. Although the transporter18may be inherently unstable in an un-powered state, a control loop process balances the transporter over a pair of coaxial wheels,20and21. In response to relatively minor movements by the user, the transporter18can accelerate, maintain speed, turn, decelerate, stop, etc. Further details regarding the principles and operation of such a transporter18are provided in U.S. Pat. No. 6,302,230, which is incorporated herein by reference.

FIG. 2is a block diagram of an embodiment of a dynamically stabilized transporter having an exercise mode in accordance with the present invention. In normal transport mode, a controller204controls a power source201and a motorized drive202. The motorized drive202is connected to a ground-contacting module203that uses wheels20and21or other ground-contacting members to drive the transporter18over an underlying surface.

The controller204receives multiple inputs from various sensors and from the user. Based on its inputs, the controller204controls power from the power source201to the motorized drive202to dynamically stabilize the transporter18and provide it with a desired motion as directed by the user. As shown inFIG. 2, power from the power source201may be applied directly to motorized drive202, or may be modulated by controller204. Typically, controller204uses a control algorithm that emulates variable terms such as pitch, position, wheel speed, wheel damping, pitch damping, etc. and thereby gives a user an impression that may vary from actual operating conditions of the transporter.

Dismounted Exercise Mode

To support an exercise mode, the transporter18provides a user interface205, typically one or more devices on or near the hand grip14. The user interface205enables and controls an exercise mode of controller204. The exercise mode allows the user to dismount from the platform12and work against the driving action of the ground-contacting module202at a selected level of user exertion by either pushing or pulling the transporter18. Thus, as shown inFIG. 2, during the exercise mode, power flows in the opposite direction from when the transporter is in normal operation.

In a dismounted exercise mode, controller204causes the motorized drive202to drive the wheels of the ground-contacting module203against the user's efforts based on the input from the user interface205. For example, the user interface205may include a turnable hand grip14that controls the speed of the wheels, and the user turns the hand grip14to increase or decrease the user's work load, as described in U.S. patent application Ser. No. 10/308,888, filed Dec. 3, 2002, entitled “Security Features for a Personal Transporter,” and incorporated herein by reference. Besides turning the hand grip14, the user could also increase or decrease the work load by changing their speed for a given position of the hand grip14. Alternatively, the user could use methods other than the user interface205. For example, given the “fly-by-wire” nature of embodiments of the personal transporter disclosed in U.S. Pat. No. 6,302,230, which is incorporated herein by reference, a personal controller key could be used to input pre-set characteristics for dismounted exercise mode.

The transporter18may be operated in either a voltage mode or in a current mode. For example, in follow mode as described in U.S. patent application Ser. No. 10/308,888, the transporter18may typically be operated in a current mode, so that the torque produced by the wheels is proportional to, or otherwise a function of, the user input command. In exercise mode, the transporter18may also be operated in a current mode, but with the current command Icmdset as a function of the motor speed ωmgin such a way as to produce a desired drag force. For example, Icmdcould be set to −K·ωmto simulate viscous drag (with drag torque proportional to speed). Alternatively, for example, Icmdcould be set as a function of the square of the speed, for example using the equations Icmd=−K·ωm|ωm| or Icmd=−K·ωm·sin (ωm). Alternatively, Icmdcould be set to −K·ωmfor ωm<0 and Icmdcould be set to 0 for ωm>0. This simulates viscous drag for motion in the negative (reverse) direction, with no drag in the positive (or forward) direction, as is typically the case with rowing machines and other exercise equipment.

Typically, a transporter18will have some mechanical inefficiencies that result in losses associated with turning the wheels20and21, e.g., friction and electrical resistance losses. Thus, much of the work that user does in exercise mode may be dissipated as heat in the transmissions and motors associated with the ground-contacting module203. If, however, the user does more work than is absorbed by these losses and inefficiencies (i.e., pushes fast enough and hard enough), that additional work may be returned to the power source201(which is generally a group of batteries), acting to recharge it. Alternatively, the user-provided human power input may generate an electric current that is dissipated as heat by a component such as a resistor.

Typical embodiments also include a display associated with the user interface205. When the controller204is in exercise mode, the display may provide useful information such as an estimate of how many calories the user has burned. Of course, such an estimate would be based on an approximation of the amount of work dissipated by the losses and inefficiencies, and would not reflect other effects such as changing elevation as the transporter18goes up and down hills. The display may also indicate the rate of calories being burned, the current charge of the power source201, or the rate of change of the charge of the power source201.

Dynamically Stabilized Exercise Mode

An embodiment also may allow the user to engage the exercise mode while remaining on the platform12. For example, the controller205may utilize a stabilizing algorithm that allows the user to work the device back and forth while remaining substantially in one place. In this configuration, the transporter18sluggishly moves fore-and-aft or side-to-side causing the energy of the motion to be reabsorbed. This may involve adding a position term, pitch damping term, and/or wheel damping term to the stabilizing algorithm employed by the controller204.

FIG. 3is a simplified block diagram of a stabilizing algorithm of a controller204having an exercise mode according to one embodiment of the invention. The simplified control algorithm ofFIG. 3maintains stability and also proximity to a reference point on the underlying surface in the presence of disturbances such as changes to the system's center of mass with respect to the reference point on the surface due to body motion of the subject or contact with other persons or objects. Plant61is equivalent to the equations of motion of a system with a ground-contacting module203driven by a single motor, before a control loop is applied. Wheel torque is shown by the reference T. Boxes62and63perform differentiation. To achieve dynamic control that insures stability of the system, and to keep the system in the neighborhood of a reference point on the surface, the wheel torque T is governed by the following simplified control equation:
T=K1(θ−θ0)+K2({dot over (θ)}−{dot over (θ)}0)+K3(x−x0)+K4({dot over (x)}−{dot over (x)}0),
where:T represents torque applied to a ground-contacting element about its axis of rotation;θ represents lean of the entire system about the ground contact, with θ0representing the system pitch offset;x represents fore-aft displacement along the under-lying surface relative to a fiducial reference point, with x0representing a specified fiducial reference offset;a dot mark over a character denotes a differentiation with respect to time of the variable; anda subscripted variable denotes a specified offset that may be input into the system as described below; andK1, K2, K3, and K4are gain coefficients that may be configured, either in design of the system or in real-time, on the basis of a present operating mode and operating conditions as well as preferences of a user. These gain coefficients may be positive, negative, or zero, affecting thereby the mode of operation of the transporter device, as discussed below. The gains K1, K2, K3, and K4are dependent upon the physical parameters of the system and other effects such as gravity. For example, the gain coefficients may be used to model position stiffness, pitch stiffness, pitch damping, or wheel damping so as to implement one or more exercise modes according to an embodiment of the invention.

The effect of θ0in the above control equation is to produce a specified offset −θ0from the non-pitched position where θ=0. Therefore, adjustment of θ0will adjust the transporter device's offset from a non-pitched position. When the controller204is engaged in the exercise mode, this pitch offset term may be adjusted to allow user control of the attitude of the transporter. For example, pitch offset may be adjusted by the user by turning hand grip14, shown in FIG.1.

Of course, such an adjustable pitch offset is useful under a variety of other circumstances besides an exercise mode, for example, when operating the transporter device on a steep upward or downward incline. Under these circumstances, θ0may advantageously be manually offset to allow control with respect to a stationary pitch comfortable to the user.

The size of K3will determine the extent to which the transporter device will seek to return to a given location. With a non-zero K3, the effect of x0is to produce a specified offset x0from the fiducial reference by which x is measured. When K3is zero, the transporter device has no bias to return to a given location. The consequence of this is that if the transporter device is caused to lean in a forward direction, the transporter device will move in a forward direction, thereby maintaining balance. Thus, by controlling the position term K3along with the pitch offset term θ0, an embodiment of the present invention may allow the transporter device to be operated in an exercise mode in which the device moves alternately in opposite directions so as to maintain a relatively constant position.

In order to accommodate two wheels instead of the one-wheel system illustrated for simplicity inFIG. 3, separate motors may be provided for left and right wheels of the transporter18, and the torque desired from the left and right motors can be calculated separately. Additionally, tracking both the left and right wheel motions permits adjustments to be made to prevent unwanted turning of the vehicle and to account for performance variations between the two ground contacting members or drive motors, as described, for example, in U.S. Pat. No. 6,288,505, issued Sep. 11, 2001.

Other Exercise Modes

FIG. 4shows another embodiment of the present invention in which a transporter18having an exercise mode is supported above the ground by a platform42, and coupled to an exercise bike40. In the embodiment shown inFIG. 4, the coupling mechanism is based on a connecting belt41that is fitted around one of the transporter wheels21, and which connects to the interior mechanical workings of the exercise bike40. In other embodiments, a direct mechanical coupling such as transmission may connect the transporter18to the exercise bike40. Similar principles can be used to couple an exercise mode transporter to other exercise devices such as stair-climbers, treadmills, elliptical trainers, rowing machines, etc. In addition, an embodiment could couple an exercise mode transporter to a regular bicycle which has its back wheel lifted off the ground.

In such an embodiment, the transporter18can be operated in one of the voltage modes or current modes described above so that the ground engaging module203provides a torque to the wheel21that resists the exercise efforts of a user pedaling on the exercise bike40. In addition or alternatively, the user's exercise efforts on the exercise bike40can be used as described above to recharge the power source201.

Although various exemplary embodiments of the invention have been disclosed, it should be apparent to those skilled in the art that various changes and modifications can be made which will achieve some of the advantages of the invention without departing from the true scope of the invention. For example, the foregoing description of an exercise mode that resists the user has been provided in the context of a dynamically stabilized transporter, but embodiments of the invention are not limited to such a device and may advantageously be implemented on any personal transporter device.