GB2563856A

GB2563856A - Controlling a cycle

Info

Publication number: GB2563856A
Application number: GB1710232.8A
Authority: GB
Inventors: Prime Francis
Original assignee: Arrival Ltd
Current assignee: Arrival UK Ltd
Priority date: 2017-06-27
Filing date: 2017-06-27
Publication date: 2019-01-02
Anticipated expiration: 2037-06-27
Also published as: GB2563856B; GB201710232D0

Abstract

A computer-implemented method of controlling at least one electric drive apparatus of a vehicle (in particular an electrically assisted bicycle) when the vehicle is travelling on an inclined surface, comprising: determining 51 a steepness of an inclined surface on which the vehicle is travelling; determining 52, based on the determined steepness of the inclined surface, at least one of a drive torque to apply to at least one wheel of the vehicle and a regenerative braking torque to apply to at least one wheel of the vehicle; and applying, by the at least one electric drive apparatus to at least one wheel of the vehicle, at least one of the determined drive torque and the determined regenerative braking torque. In one embodiment, the steepness of a downhill gradient may be used to calculate a maximum speed of the vehicle, regenerative braking then being employed to ensure that the vehicle does not exceed this speed.Apparatuses, including vehicles, computer readable storage mediums and computer programs are also described.

Description

Controlling a cycle

Field

This specification relates to controlling a drive apparatus of a vehicle. Particularly, but not exclusively, the specification relates to controlling the drive apparatus to apply a drive torque and/or a regenerative braking force to one or more wheels of a vehicle based on a steepness of an inclined surface on which the vehicle is travelling.

Background

Electrically-powered bicycles include an electric motor for rotating the rear wheel of the bicycle. The electric motor is included as a supplement to a conventional pedal-driven drive apparatus, via which a cyclist may push on the pedals to rotate the rear wheel of the bicycle. The motor acts to provide assistance to the cyclist when desired, for example when the cyclist is riding uphill or accelerating away from a stationary position. Such electrically-powered bicycles generally include a motor control on the handlebars, such as a rotatable grip, with which the cyclist can control the level of power supplied by the motor to the rear wheel of the bicycle.

Summary

This specification provides a computer-implemented method of controlling at least one electric drive apparatus of a vehicle when the vehicle is travelling on an inclined surface, comprising: determining a steepness of an inclined surface on which the vehicle is travelling; determining, based on the determined steepness of the inclined surface, at least one of a drive torque to apply to at least one wheel of the vehicle and a regenerative braking torque to apply to at least one wheel of the vehicle; and applying, by the at least one electric drive apparatus to at least one wheel of the vehicle, at least one of the determined drive torque and the determined regenerative braking torque.

The method may further comprise: based on the determined steepness of the inclined surface, determining a maximum torque value; and in determining the drive torque to apply to at least one wheel of the vehicle, limiting the determined drive torque to a value lower than or equal to the determined maximum torque value.

Determining the maximum torque value may comprise: determining the maximum torque value as being inversely proportional to a value indicative of the determined steepness of the inclined surface.

The method may further comprise: based on the determined steepness of the inclined surface, determining a maximum acceleration with which the vehicle may travel up the inclined surface; and in determining the drive torque to apply to at least one wheel of the vehicle, selecting a drive torque which limits the acceleration of the vehicle to a value lower than or equal to the determined maximum acceleration.

Determining the maximum acceleration with which the vehicle may travel up the inclined surface may comprise: determining the maximum acceleration as being inversely proportional to a value indicative of the determined steepness of the inclined surface.

The method may comprise: based on the determined steepness of the inclined surface, determining a maximum speed at which the vehicle may travel down the inclined surface; and in determining the regenerative braking torque to apply to at least one wheel of the vehicle, selecting a regenerative braking torque which limits the speed of the vehicle on the inclined surface to a speed equal to or lower than the determined maximum speed.

Determining the maximum speed at which the vehicle may travel down the inclined surface may comprise: determining the maximum speed as being inversely proportional to a value indicative of the determined steepness of the inclined surface.

The method may comprise: based on the determined steepness of the inclined surface, determining a maximum acceleration with which the vehicle may travel down the inclined surface; and in determining the regenerative braking torque to apply to at least one wheel of the vehicle, selecting a regenerative braking torque which limits the acceleration of the vehicle on the inclined surface to an acceleration equal to or lower than the determined maximum acceleration.

Determining the maximum acceleration with which the vehicle may travel down the inclined surface may comprise: determining the maximum acceleration as being inversely proportional to a value indicative of the determined steepness of the inclined surface.

The acceleration of the vehicle may be the acceleration due to gravity as the vehicle descends the inclined surface.

The acceleration of the vehicle may be the forward/rearward acceleration of the vehicle.

Determining the steepness of the inclined surface on which the vehicle is travelling may comprise: receiving data from at least one incline determining apparatus of the vehicle; and determining, from the received data, the steepness of the inclined surface on which the vehicle is travelling.

The at least one incline determining apparatus may comprise at least one gyroscope apparatus.

The incline determining apparatus maybe configured to: sense an incline of a surface on which the vehicle is travelling; and generate, from the sensed incline, data indicative of a steepness of the surface.

Determining the drive torque to apply to at least one wheel of the vehicle may further comprise: receiving, from at least one speedometer of the vehicle, data indicative of the speed of the vehicle on the inclined surface; and determining an increased or decreased drive torque based on whether the data indicates that the speed of the vehicle is respectively lower than or greater than a speed threshold value for the inclined surface.

Determining the drive torque to apply to at least one wheel of the vehicle may further comprise: receiving data indicating a drive power being supplied to at least one wheel of the vehicle from energy being supplied by a human operating at least one human-operable actuator of the vehicle; and determining the drive torque to apply to at least one wheel of the vehicle based on the drive power, indicated by the data, as being supplied by the human operating the at least one human-operable actuator.

The at least one human-operable actuator may comprises at least one foot or hand-operable pedal apparatus.

This specification also provides a computer program comprising computer executable instructions which, when executed by at least one computing apparatus, cause the at least one computing apparatus to perform the method.

This specification also provides a vehicle comprising: at least one computer processor; and at least one computer memory storing computer executable instructions which, when executed by at least one computer processor, cause the at least one computing apparatus to perform the method.

The vehicle may be a cycle.

The cycle may be an Electronically Power Assisted Cycle (EPAC).

The vehicle may comprise the at least one drive apparatus configured to actuate at least one wheel of the vehicle, wherein the drive apparatus comprises at least one user-operable actuator for controlling operation of the drive apparatus.

The vehicle may further comprise the incline determining apparatus.

This specification also provides a vehicle system, comprising: at least one electrical drive apparatus configured to actuate at least one wheel of the vehicle; at least one incline determining apparatus configured to determine a gradient of surface on which the vehicle is currently travelling; and at least one computing apparatus configured to select an operating state of the at least one electrical drive apparatus in dependence of the gradient of the surface determined by the at least one incline determining apparatus.

The vehicle system may comprise a cycle.

The vehicle system may comprise an Electronically Power Assisted Cycle (EPAC).

The at least one computing apparatus maybe configured to perform the method.

For the purposes of example only, embodiments are described below with reference to the accompanying figures.

Brief Description of the Figures

Figure 1 is a schematic illustration of a cycle comprising a drive apparatus operable in a plurality of operating states;

Figure 2 is a further schematic diagram of a cycle comprising a drive apparatus operable in a plurality of operating states;

Figure 3 is an illustration of a pedal apparatus arranged to transfer energy from a user of a cycle to a drive apparatus of the cycle;

Figure 4 is a schematic diagram of a cycle comprising a drive apparatus operable in a plurality of operating;

Figure 5 is an illustration of a range of operating states for a drive apparatus comprising one or more electrical motor-generator units mechanically coupled to a wheel of a cycle, and a pedal apparatus mechanically coupled to an electricity generating apparatus of the cycle;

Figure 6 is a further schematic diagram of a cycle comprising a drive apparatus operable in a plurality of operating states;

Figure 7 is a schematic diagram of a remote computing device configured to communicate with a cycle to control the operation of a drive apparatus of the cycle; and Figure 8 is a flow diagram of a method of controlling the operation of a drive apparatus of a cycle in dependence of a steepness of an inclined surface on which the cycle is travelling.

Detailed Description

The following description discusses an apparatus and method for controlling at least one drive apparatus of a vehicle in dependence of a steepness of an inclined surface upon which the vehicle is travelling. For the purposes of clarity, the embodiments are described primarily in the context of a cycle and a cyclist riding the cycle. The cycle comprises pedals via which energy provided by the cyclist is used to propel the cycle forwards. The cycle also comprises one or more electric motors for propelling the vehicle forwards. In this regard, the cycle may be an Electronically Power Assisted Cycle (EPACs) and/or a Pedelec, such as a Speed Pedelec. For the avoidance of doubt, where the vehicle is a cycle, the aspects described herein are applicable to at least twowheeled, three-wheeled and four-wheeled versions.

It will be evident to a person skilled in the art that the aspects described herein are applicable not only to cycles but also to vehicles in general which are powered, at least partially, by energy provided by an operator of the vehicle.

Figure 1 is a schematic illustration of a cycle too. The cycle too comprises a pair of front wheels 101 and a pair of rear wheels 102. The cycle too also comprises a chassis 103, for example in the form of a frame. The front wheels 101 are steerable relative to the chassis 103, for example via a rack and pinion steering apparatus. The rear wheels 102 may also be steerable relative to the chassis 103 using a similar steering apparatus. The one or more steering apparatuses (not shown) are coupled to a user-operable steering actuator 104, which may take the form of a handlebar which can be turned by the user to steer the wheels 101,102. Both the front wheels 101 and the rear wheels 102 are arranged to rotate relative to the chassis 103 to facilitate forwards and rearwards movement of the cycle 100.

In an alternative example, where the cycle has only a single front wheel, the front wheel 101 may be rotatably located in a fork (not shown). As will be understood by those skilled in the art, the fork acts as a steering apparatus. The forks can be turned within a head tube of a frame of the cycle to permit a cyclist to steer the front wheel of the cycle. The cyclist is able to turn the fork by appropriate movement of a steering actuator, such as a handlebar attached to the fork.

As shown in figure 1, the cycle 100 comprises a seat 105 on which a cyclist may sit to operate the cycle 100. The cycle 100 may also comprise one or more storage regions 106. For example, a first storage region 106a may be located under the seat 105 and a second storage region 106b maybe located further towards a rear of the cycle 100. The cycle 100 may further comprise one or more brakes 107, for example in the form of disc brakes, for slowing the rate of rotation of one or more wheels 101,102 of the cycle 100 under the control of the cyclist. In the example of figure 1, first and second brakes 107 are respectively configured to brake the first and second front wheels 101 of the cycle 100, under the control of the cyclist.

The cycle 100 also comprises a drive apparatus 200 for rotating one or more drivable wheels of the cycle 100. The principal elements of the drive apparatus 200 are described below with respect to figure 2 to 4. In the following discussion, the drive apparatus 200 is explained as being configured to drive rotation of the rear wheels 102 only, with the front wheels 101 being non-driven but free to rotate. However, in another example, the front wheels 101 may also be driven by the drive apparatus 200.

Referring firstly to figure 2, which shows some of the principal elements of the drive apparatus 200 as part of a schematic illustration of the cycle 100, the drive apparatus 200 includes at least one user-operable actuator for allowing the cyclist to transfer energy from his/her body to the drive apparatus 200 by exerting a force on the user-operable actuator. This energy is used by the drive apparatus 200 to rotate the rear wheels 102. In the context of the cycle too, the user-operable actuator comprises a pedal apparatus 201, which is arranged to allow the cyclist to transfer energy from his/her legs to the drive apparatus 200 by exerting a force on the pedal apparatus 201.

An example of a pedal apparatus 201 is shown in more detail in figure 3. As can be seen from figure 3, the pedal apparatus 201 may comprise a chain 201a, a rotatable chain ring 201b, a sprocket 201c, and a pair of pedals 20id. In this example, the chain 201a is coupled between the rotatable chain ring 201b and the sprocket 201c, whilst the pedals 20id are attached to the chain ring 201b via cranks. In use, a cyclist may use his or her legs to apply pressure to the pair of pedals 20id, thereby rotating the chain ring 201b and causing a corresponding rotation ofthe sprocket 201c.

In a first implementation of the drive apparatus 200, the sprocket 201c is mechanically coupled to the rear wheels 102 of the cycle too so that a rotation of the sprocket 201c translates directly into a corresponding rotation of the rear wheels 102.

In a second, alternative, implementation of the drive apparatus 200, around which the following discussion is based, the sprocket 201c is mechanically coupled to an electricity generating apparatus 202. In this second implementation, movement of the pedals 20id by the cyclist causes kinetic energy in the pedal apparatus 201 to be transferred to the electricity generating apparatus 202 rather than directly to the rear wheels 102 of the cycle too. Movement of the pedals 20id may, for example, cause a corresponding movement of one or more magnetic elements in the electricity generating apparatus 202. Kinetic energy in these moving elements may be converted into electrical energy in a manner which is well understood by persons skilled in the art. It will be appreciated that although the mechanical coupling between the pedal apparatus 201 and the electricity generating apparatus 202 is described above in the context of the chain 201a and the sprocket 201c, the mechanical coupling may alternatively be embodied using other suitable mechanical elements. The electricity generating apparatus 202 maybe part ofthe drive apparatus 200.

The electricity generating apparatus 202 is included in the schematic illustration of the cycle too shown in figure 2, along with other principal elements of the drive apparatus 200. As shown in figure 2, in addition to the pedal apparatus 201 and the electricity generating apparatus 202, the drive apparatus 200 of the cycle too further comprises one or more electric motors 203. These electric motors 203 are each described below in the context of a motor-generator-unit (MGU). Figure 2 illustrates a first MGU 203 located at a first of the rear wheels 102 and a second MGU 203 located at a second of the rear wheels 102. The first and second MGUs 203 are respectively configured to actuate a rotation of the rear wheel 102 at which they are located.

Referring again to figure 2, the drive apparatus 200 of the cycle too further comprises one or more electrical storage elements, each of which comprises a battery 204. The battery 204 of each electrical storage element (or batteries 204 if more than one is present) is rechargeable and is electrically coupled to the MGUs 203. The battery 204 is configured to supply electrical power to the MGUs 203 via the electrical coupling. For example, as shown in figure 2, the electrical coupling between the battery 204 and the MGUs 203 may include a power inverter apparatus 205 in order to convert DC power provided by the battery 204 to AC power used at the MGUs 203. The battery 204 may also receive electrical power from the MGUs 203 via the inverter apparatus 205, as discussed further below, for the purposes of re-charging.

In addition to being electrically coupled to the MGUs 203, the battery 204 of each storage element in the drive apparatus 200 maybe electrically coupled to the electricity generating apparatus 202 discussed above. Electrical energy generated at the electricity generating apparatus 202 from kinetic energy input via the pedal apparatus 201 may be supplied to the battery 204 in order to re-charge the battery 204. As with the electrical coupling between the battery 204 and the MGUs 203, the electrical coupling between the electricity generating apparatus 202 and the battery 204 of each electrical storage element may comprise a power inverter apparatus 206 to convert AC power supplied by the electricity generating apparatus 202 to DC power for charging the battery 204.

The battery 204 of each electrical storage element may comprise, for example, a 48V battery 204. The electrical coupling between the battery 204 and the inverter apparatuses 205, 206 may comprise a 48V DC bus, whereas the electrical coupling between the inverter apparatuses 205, 206 and the MGUs 203/electricity generating apparatus 202 may comprise an AC coupling. The battery 204 may re-chargeable be rechargeable from an external source, such as a mains power source a specific charging apparatus, via a charging port (not shown).

During actuation of the wheel(s) 101,102 of the cycle 100 by the MGUs 203, electrical energy flows between the batteries 204 of the electrical storage apparatus(es) and the MGUs 203. In this context, actuation of the wheel(s) 101,102 by the MGUs 203 may involve either an acceleration of the rotation of the wheels 102 or a braking of the rotation of the wheels 102. As will be explained below, the direction in which the electrical energy flows between the batteries 204 and the MGUs 203 depends on the current operating state of the drive apparatus 200.

Referring to figure 4, which is a schematic diagram of the drive apparatus 200, the drive apparatus 200 further comprises an electronic controller 207, such as an electronic microcontroller, for controlling the drive apparatus 200 to operate in one of a plurality of selectable operating states. For example, the controller 207 maybe configured to control the operation of the one or more MGUs 203 and the one or more batteries 204 in a particular fashion in order to cause the drive apparatus 200 to operate in a selected state. Additionally or alternatively, the controller 207 may be configured to control the operation of the electricity generating apparatus 202 in a particular fashion in order to cause the drive apparatus 200 to operate in a selected state. The plurality of selectable operating states may, for example, represent a continuum of operating states for the drive apparatus 200. The ends of this continuum may correspond to the operating states which respectively provide a maximum resistance to rotation of the wheel(s) 102 of the cycle 100 and a maximum acceleration of the rotation of the wheel(s) 102 of the cycle 100. A change in the operating state of the drive apparatus 200 falls into one of two principal types. In a first type of change in the operating state, the drive apparatus 200 is configured to reduce the drive torque/increase the braking force being applied to the rear wheels 102 of the cycle 100 by the MGUs 203. In a second type of change in the operating state, the drive apparatus 200 is configured to increase the drive torque/reduce the braking force being applied to the rear wheels 102 of the cycle 100 by the MGUs 203. The two types of operating state change allow the drive apparatus 200 to be used to vary the level of motor assistance provided to the cyclist over time. In particular, when the cycle 100 is travelling up an inclined surface, the drive apparatus 200 may provide motor assistance to supplement the cyclist’s pedalling effort by operating in a motor-assist state. Such a motor-assist state involves supplying energy to the MGUs 203, for the purposes of accelerating rotation of the rear wheels 102, at a rate which is greater than the rate of energy currently being supplied to the electricity generating apparatus 202 by the pedal apparatus 201. The additional energy may be supplied by the one or more batteries 204 of the energy storage elements, using energy that was stored in the one or more batteries 204 beforehand. As explained below, the specific nature of this motor assistance maybe selected in dependence of the steepness of the incline up which the cycle too is travelling.

Correspondingly, when the cycle too is travelling down an inclined surface, the drive apparatus 200 may provide wheel-braking by operating in a regenerative braking state. Such a regenerative braking state involves recovering energy from the rotation of the rear wheels 102 using the MGUs 203, for the purposes of slowing the rotation of the wheels 102. In particular, the MGUs 203 are configured to convert kinetic energy in the wheels 102 to electrical energy. The recovered electrical energy is supplied to the one or more batteries 204 of the energy storage elements, for example for re-charging the batteries 204 or for use in powering other elements of the cycle too. The specific nature of the braking provided by this energy recovery may be selected in dependence of the steepness of the incline to ensure that the cycle too descends the incline in a safe manner.

Figure 5 illustrates a continuum of selectable operating states for a drive apparatus 200 comprising a pedal apparatus 201 which is mechanically coupled to an electricity generating apparatus 202 of the type described above, one or more MGUs 203 and one or more batteries 204 of one of more electrical storage elements. As explained above, in this type of drive apparatus 200, kinetic energy provided by the cyclist to the pedal apparatus 201 is transferred to the electricity generating apparatus 202. The electricity generating apparatus 202 converts the kinetic energy to electrical energy and supplies the electrical energy to the one or more batteries 204 for re-charging. When the drive apparatus 200 is operating in a motor-assist state, the driveable wheels 102 of the cycle 100 are rotated by the one or more MGUs 203, by supplying a drive torque to the wheels 102 using electric energy supplied to the MGUs 203 by the one or more batteries 204. When operating in a regenerative braking state, the MGUs 203 apply a braking torque to the wheels 102 to recover electrical energy from the wheels 102 and supply the recovered energy the one or more batteries 204.

The continuum illustrated in figure 5 has two end points which respectively correspond to drive apparatus operating states at which the resistance to rotation of the wheels 102 is maximum and assistance to rotation of the wheels 102 is maximum. A central point on the continuum may correspond to a so-called free-wheel state, in which the wheels 102 are allowed to rotate freely by the drive apparatus 200 without any substantial interference from the MGUs 203.

The controller 207 may be configured to select the operating state of the drive apparatus 200 based on at least one of two considerations. A first of these considerations may be the type of, and degree to which, control inputs are being provided to the cycle too by the cyclist. These control inputs may come in the form of actuations of a brake lever, or similar, at the handlebar 104 of the cycle 100. In response to actuation of a brake lever, for example, the controller 207 may be configured to select a regenerative braking state of the drive apparatus 200 to cause the MGUs 203 to recover energy from the rotation of the rear wheels 102 and thereby slow the forward (or rearward) motion of the cycle too. A second consideration upon which the controller 207 may select the operating state of the drive apparatus 200 is the gradient of the surface upon which the cycle too is currently travelling. As outlined briefly above, the controller 207 may be configured to select a regenerative braking state of the drive apparatus 200 when the cycle too is travelling down an incline so as to limit the speed at which the cycle too descends the slope. Correspondingly, the controller 207 maybe configured to select a motor assist state of the drive apparatus 200 when the cycle is travelling up an incline so as to supplement the power being provided by the cyclist through the pedal apparatus 201.

As explained below, the selection of the operating state of the drive apparatus 200 may be based not only on whether the cycle too is travelling up/down an incline, but further on the current gradient of the incline and/or the current speed of the cycle too. For example, if the cycle too is travelling up a relatively shallow incline, the controller 207 may be configured to operate in a relatively low level motor assist state to supplement the power being provided by the cyclist through the pedal apparatus 201. If the gradient of the incline becomes steeper, however, the controller 207 may be configured to select a relatively higher level motor assist state to further supplement the power being provided by the cyclist and thereby provide additional help to the cyclist in ascending the slope.

In such a transition between operating states of the drive apparatus 200, the controller 207 may be configured to select the rate of the transition in dependence of the gradient of the incline. For example, if the incline is initially shallow and it is determined that the incline is gradually increasing in gradient, the controller 207 may be configured to smoothly switch to the new operating state over a relatively short period of time. Over this relatively short period of time, the amount of additional power being supplied to the MGUs 203 by the one or more batteries 204 increases rapidly and is converted by the MGUs 203 to drive torque applied to the rear wheels 102. If, however, it is determined that the increase in gradient is more dramatic, the controller 207 may be configured to smoothly switch to the new operating state over a relatively longer period of time. Although this may initially seem counter-intuitive, the longer period of transition ensures that any increase in the rate of rotation of the rear wheels 102 is not so large as to cause the front wheels 101 of the cycle too to be lifted off the ground and for the cycle 100 to tip backwards. A similar principle may be applied by the controller 207 when the cycle 100 is determined to be travelling up a steep gradient. Changes in the operating mode of the drive apparatus 200, particularly those which involve an increase in additional power being supplied from the batteries 204 to the MGUs 203 for rotating the wheels 102, maybe carried out over a period of time which is proportional to the gradient of the incline upon which the cycle 100 is travelling in order to minimize any risk of causing instability of the type referred to above.

In a situation where the cycle 100 is travelling down an incline rather than up it, the controller 207 may be configured to select an operating state of the drive apparatus 200 which ensures safe progress down the slope. The specific manner in which the controller 207 selects the operating state under these conditions may vary in dependence of, for example, the loaded weight of the cycle 100 or preset parameters such as user preferences. However, in general, the controller 207 may operate the drive apparatus 200 and, in particular, the MGUs 203, to ensure that the cycle 100 does not exceed particular levels of forward acceleration and/or speed when travelling down the slope. These particular levels of acceleration and/or speed may be linked to the steepness of the gradient on which the cycle 100 is currently travelling. For example, the controller 207 may permit a relatively high acceleration and/or speed on relative shallow downward slopes, whilst permitting only a relatively lower acceleration and/or speed when the cycle 100 is travelling down a relatively steeper slope.

The controller 207 may, for example, increase the regenerative braking force being applied to the wheels 102 by the MGUs 203 as the gradient on which the cycle too is descending gets larger. The increase in braking force caused by controller 207 may be selected and applied automatically in response to a signal indicative of an increase in surface gradient. Likewise, corresponding reductions in braking force may be selected and applied automatically in response to a signal indicative of a decrease in surface gradient.

In addition to the above, the controller 207 may cause the level of regenerative braking force applied to the wheels 102 to be increased as the speed of the cycle too gets closer to a threshold maximum speed (which may be stored in memory). The level of regenerative braking maybe inversely proportional to a difference between the current speed of the cycle too and the threshold maximum speed for the particular gradient on which the vehicle is travelling, for instance, when the cycle too is above a particular braking-trigger speed threshold.

As with the application of drive torque discussed above, the application of braking force to the wheels 102 using the MGUs 203 is intended to limit any instability caused to the cycle too during braking. The braking force is applied smoothly, at a rate which is appropriate to prevent locking of the wheels 102 and/or other instabilities in the movement of the cycle too. For example, if regenerative braking is applied to the front wheels 101 of the cycle too, the application of the braking force maybe moderated to ensure that braking of the front wheels 101 does not cause the rear wheels 102 to leave the ground - thereby causing the cycle too to tip forwards.

In order to facilitate the control of the drive apparatus 200 based on the steepness of an incline in the manner discussed above, the cycle too comprises at least one incline determination apparatus 300. The incline determination apparatus 300 is shown in the schematic illustration of figure 6, which is in some respects similar to figure 2. The incline determination apparatus 300 may comprises at least one gyroscope apparatus 301 for generating a signal indicative of the gradient on which the cycle too is travelling. Additionally or alternatively, the incline determine apparatus 300 may comprise at least one accelerometer apparatus 302 for generating a signal indicative of the gradient on which the cycle too is travelling. The incline determination apparatus 300 is configured to supply the signal(s) indicative of the gradient of the surface on which the cycle 100 is currently travelling directly to the controller 207 of the drive apparatus 200, so that the controller 207 may select an appropriate operating state for the drive apparatus 200 in dependence of the steepness of the incline and the direction in which the cycle 100 is travelling in the incline.

As shown in figure 6, the cycle 100 also comprise at least one speedometer apparatus 400 and further accelerometer apparatus 500 for determining the forward/rearward speed and acceleration of the cycle 100. The determined speed and acceleration of the cycle 100 is provided by these apparatuses 400, 500 to the controller 207 of the drive apparatus 200.

Although the controller 207 is described above solely in the context of a controller 207 integrated with the cycle too, the controller 207 may alternatively operate in combination with a remote computing apparatus, such as a mobile user computing device 600. The mobile device 600 may comprise a smartphone or a tablet computer, for example, which may installed in a mobile device dock 700 of the cycle too. The dock 700 may receive power from the one or more batteries 204 discussed previously, for example via a transformer, in order charge and generally power the mobile device 600 when in the dock 700. The control aspects discussed above, in terms of selection of the operating state of the drive apparatus 200, may be carried out on a controller 601 of the mobile device 600 rather than in the controller 207 of the drive apparatus 200. For example, the controller 207 of the drive apparatus 200 may be configured to forward information regarding the steepness of the surface gradient, together with speed and acceleration information for the cycle too, to the mobile device 600 in order to allow the controller 601 of the mobile device 600 to select an appropriate operating state for the drive apparatus 200.

For this purpose, as shown in figures 4 and 6, the drive apparatus 200 may also comprises a transceiver 208, which is configured to send data from the drive apparatus 200 to the mobile device 600. The transceiver 208 may also receive data from mobile device 600, for example in the form of control instructions for the drive apparatus 200. In addition to that already discussed above, the data sent to the mobile device 600 may include, for example, information indicating the current operating state of the drive apparatus 200.

Figure 7 is a schematic diagram of a user computing device 600, such as a smart phone, tablet, or a wearable device, such as a smart watch. The user device 600 comprises a controller 601, comprising at least one computer processor 601a, and at least one computer memory 601b, and an electrical power source 602 including a battery 603. The user device 600 also comprises a display 604 and a user-input apparatus 605, via which a user may provide inputs to the device 600. The user-input apparatus 605 may, for example, comprise a touch-sensitive panel which is integrated with the display 604 in a touch-screen display. The user device 600 also comprises a transceiver 606 for communicating with external apparatuses, such as the transceiver 208 and, thereby, the controller 207 of the drive apparatus 200 of the cycle 100. Communication between the transceivers of the drive apparatus 200 and user computing device 600 may be via a suitable wireless communication link, such as Bluetooth.

In examples where the determination of an appropriate operating state for the drive apparatus 200 is made in the user computing device 600, the computer memory 601b of the user device 600 contains an application program 800 for controlling the operation of the drive apparatus 200. The application program 800 may cause the user device 600 to send instructions to the controller 207 of the drive apparatus 200 to control the operational state of the drive apparatus 200, as described above. In examples where the determination of an appropriate operating state for the drive apparatus 200 is made in the controller 207 of the drive apparatus 200, the application program 800 is stored and executed at the controller 207 of the drive apparatus 200.

An example method of controlling the operation of the drive apparatus 200 based on a steepness of an inclined surface in which a cycle 100 is travelling is described below with respect to figure 8. The method is described as being carried out by the controller 207 of the drive apparatus 200. However, the method could alternatively be carried out by a controller 601 of the mobile user device 600 described above (for example).

In a first stage Si, a method of controlling the drive apparatus 200 of a cycle 100 when the cycle 100 is travelling on an inclined surface comprises determining a steepness of the inclined surface on which the cycle 100 is travelling. For example, the incline determination apparatus 300 may continuously determine a gradient of a surface on which the cycle 100 is travelling and generate a signal, which is indicative of the gradient, for output to other elements of the cycle 100. In particular, the signal maybe an electrical signal which is communicated to the controller 207 of the drive apparatus 200 described above.

In a second stage S2, the method comprises determining, based on the determined steepness of the inclined surface, at least one of a drive torque to apply to at least one wheel 102 of the cycle too and a regenerative braking force to apply to at least one wheel 102 of the cycle too. For example, the controller 207 of the drive apparatus 200 may determine based on the gradient indicated by the incline determination apparatus 300 and movement information for the cycle too, such as the direction of rotation of the wheels 101,102, whether the cycle 100 is currently travelling up or down an inclined surface. If it is found that the cycle too is currently travelling up an inclined surface, the controller 207 may select a motor assist state for the drive apparatus 200 in order to help the cyclist to ascend the slope in the manner described above. The specific level of motor assist, in terms of the amount of supplementary power which is provided to the MGUs 203 over and above the power that is currently being provided to the drive apparatus 200 by the cyclist through the pedal apparatus 200, is selected in dependence of the gradient of the slope. For example, the final level of motor assist may be selected as proportional to the magnitude of the gradient up which the cycle too is currently travelling.

In determining to apply additional drive torque to the wheels 102 of the cycle too in a motor assist state of the drive apparatus 200, the method may additionally or alternatively involve the controller 207 determining a maximum torque value for driving rotation of the wheels 102, based on the determined steepness of the inclined surface. In determining the drive torque to apply to the wheels 102 of the cycle too, the controller 207 may select an operating state for the drive apparatus 200 which limits the overall drive torque applied by each MGU 203 to a value lower than or equal to the determined maximum torque value. The maximum torque value may be determined by the controller 207 as being inversely proportional to a value indicative of the determined steepness of the inclined surface on which the cycle too is travelling.

In determining to apply additional drive torque to the wheels 102 of the cycle too in a motor assist state of the drive apparatus 200, the method may additionally or alternatively involve the controller 207 determining a maximum acceleration with which the cycle too may travel up the inclined surface, based on the determined steepness of the inclined surface. In determining the drive torque to apply to the wheels 102 of the cycle too, the controller 207 may select an operating state for the drive apparatus 200 which limits the acceleration of the cycle too to a value lower than or equal to the determined maximum acceleration. The maximum acceleration may be determined by the controller 207 as being inversely proportional to a value indicative of the determined steepness of the inclined surface.

If, on the other hand, it is found that the cycle too is currently travelling down an inclined surface, the controller 207 may select a regenerative braking state for the drive apparatus 200 in order to help the cyclist to descend the slope in a safe manner, as described above. The specific level of regenerative braking, in terms of the amount of braking torque which is applied by the MGUs 203 to reduce the rate of rotation of the wheels 102, is selected in dependence of the gradient of the slope. For example, the final level of regenerative braking torque may be selected as proportional to the magnitude of the gradient down which the cycle too is currently travelling.

In determining to apply regenerative braking torque to the wheels 102 of the cycle too in a regenerative braking state of the drive apparatus 200, the method may additionally or alternatively involve the controller 207 determining a maximum speed at which the cycle too may travel down the inclined surface, based on the determined steepness of the inclined surface. In determining the regenerative braking torque to apply to the wheels 102 of the cycle too, the controller 207 may select an operating state for the drive apparatus 200 which limits the speed of the cycle too on the inclined surface to a speed equal to or lower than the determined maximum speed. The maximum speed may be determined by the controller 207 as being inversely proportional to a value indicative of the determined steepness of the inclined surface.

In determining to apply regenerative braking torque to the wheels 102 of the cycle too in a regenerative braking state of the drive apparatus 200, the method may additionally or alternatively involve the controller 207 determining a maximum acceleration with which the cycle too may travel down the inclined surface, based on the determined steepness of the inclined surface. In determining the regenerative braking torque to apply to the wheels 102 of the cycle too, the controller 207 may select an operating state for the drive apparatus 200 which limits the acceleration of the cycle too on the inclined surface to an acceleration equal to or lower than the determined maximum acceleration. The maximum acceleration may be determined by the controller 207 as being inversely proportional to a value indicative of the determined steepness of the inclined surface.

In general, the controller 207 may select an operating state for the drive apparatus 200 in order to provide an increased or decreased drive torque to the wheels 102 based on whether data from a speedometer apparatus indicates that the speed of the cycle 100 is respectively lower than or greater than a speed threshold value for the inclined surface.

The method may generally involve determining whether to supply additional energy to the MGUs 203 which is over and above the energy currently being supplied to the drive apparatus 200 by the cyclist. In this regard, determining the operating state for the drive apparatus 200, and thus the drive torque to apply to the wheels 102 of the cycle 100 may further comprise receiving data indicating a drive power being supplied to the drive apparatus 200 by a cyclist operating the pedal apparatus 201, and determining additional power to supply to the MGUs 203, for the purposes of additional drive torque, based on the drive power indicated by the data as being supplied by the cyclist.

In a third stage S3, the method comprises applying, by the drive apparatus 200 to at least one wheel 102 of the cycle 100, at least one of the determined drive torque and the determined regenerative braking force. This may involve the controller 207 implementing the selected operating state of the drive apparatus 200 by controlling the operation of the MGUs 203 and the batteries 204 to reduce or increase the rate of rotation of the wheels 102 of the cycle 100.

In further examples, the selection of the operating state of the drivetrain apparatus 200 may consider not only the aspects discussed above but also one or more of the cyclist’s heart rate, and other geographical factors such as road surface and altitude. These factors may be provided to the controller 207, or other computing apparatus controlling the drive apparatus 200, by map information stored in a memory 402 of the cycle 100 and/or GPS position data indicating the current location ofthe cycle 100.

The user-operable actuator through which the cyclist supplies drive energy to the drive apparatus 200, the functionality of which is described above in the context of the pedal apparatus 201, may alternatively take forms such as one or more user-operable levers.

If the vehicle is a wheelchair, for example, the pedal apparatus 200 may be operated by hand rather than by a cyclist’s feet.

In the embodiments described above, energy harvested by the MGUs 203 when the MGUs 203 are operating in an regenerative braking state is supplied to the one or more batteries 204 for re-charging or for powering other elements of the cycle too. If the one or more batteries 204 are fully charged, this energy maybe dissipated in an electrically resistive element of the drive apparatus 200.

The drive apparatus 200 may comprise a button or other user-actuatable switch for disabling the control of the operating state of the drive apparatus 200 based on the steepness of the inclined surface on which the cycle 100 is travelling, when desired by the cyclist.

The pedal apparatus 201 described above may optionally comprise a torque sensing apparatus 20ie, which is configured to determine a torque received at the pedal apparatus 201 from the cyclist through rotation of the pedals 20id. The determined torque, which may for example alternatively be calculated at the controller 207 based on a signal from the torque sensing apparatus 20ie, may be used in combination with the determined steepness of the incline to control the MGUs 203 and batteries 204 of the drive apparatus 200. In particular, the determined torque may be used, in combination with the determined gradient on which the cycle too is travelling and the direction of travel on the gradient, to select an appropriate operational mode of the drive apparatus 200.

For example, in cases where the torque received from the cyclist is determined to be high and the cycle too is travelling uphill, the controller 207 may be configured to select a relatively powerful motor-assist mode of the drive apparatus 200 to help the cyclist ascend the slope. On the contrary, if the torque input is lower, it may be determined that the cyclist is in less difficulty and requires less motor assistance.

Where it is determined that the cycle too is travelling on the flat or downhill, the controller 207 may be configured to limit the level of motor assistance, by limiting the operational mode of the drive apparatus 200, regardless of the determined torque being received from the cyclist. This may ensure that the cycle too does not reach undesirably high speeds.

The cycle 100 may also comprise at least one steering angle sensing apparatus 900, which is configured to determine the angle of the steered wheels, such as the front wheels 101, relative to the frame 103 or chassis of the cycle too. The steering angle sensing apparatus 900 is configured to supply information indicative of the steering angle to the controller 207, or alternative control apparatus, which may in turn be configured to limit the operational mode of the drive apparatus 200 based on the steering angle. For example, if the steering angle is relatively high, such as above a threshold angle, the drive apparatus 200 maybe prevented from actuating the MGUs 203 to accelerate the cycle too. Below the threshold angle, a graduated approach may be taken, so that the degree to which the MGUs 203 can be activated to accelerate the cycle too is inversely proportional to the determined steering angle.

The operational mode of the drive apparatus 200 may additionally or alternatively be selected on the basis of the load on the cycle too, including the weight of the cyclist, any passengers and luggage in the storage regions 106a, 106b. Higher drive torques may be permitted from the MGUs 203 when the load on the cycle too is higher. Additionally, the MGUs 203 may be controlled to prevent the cycle too from toppling over, based on the load on the cycle too. For example, if large amounts of added weight are present behind the rear wheels of the cycle too, in a storage region 106b located there, the MGUs 203 may be controlled to appropriately actively control the rear wheels 102 to prevent the front wheels 101 from being lifted off the ground by the added weight. In order to facilitate this control, the cycle too may comprise an added weight sensing apparatus 1000, which feeds information to the controller 207. Alternatively, the added weight may be calculated by the controller 207 based on the rate at which the cycle too accelerated when a particular drive torque is applied by the MGUs 203, using Newton’s second law (F=ma).

Embodiments of the present disclosure may be implemented in software, hardware, application logic or a combination of software, hardware and application logic. The software, application logic and/or hardware may reside on memory, or any computer media. In an example embodiment, the application logic, software or an instruction set is maintained on any one of various conventional computer-readable media. In the context of this document, a “computer-readable medium” maybe any media or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer. A computer-readable medium may comprise a computer-readable storage medium that may be any tangible media or means that can contain or store the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer as defined previously.

According to various embodiments of the previous aspect of the present disclosure, the computer program according to any of the above aspects, may be implemented in a computer program product comprising a tangible computer-readable medium bearing computer program code embodied therein which can be used with a controller for the implementation of the functions described above.

Reference to “computer-readable storage medium”, “computer program product”, “tangibly embodied computer program” etc., or a “controller” or “processing circuit” etc. should be understood to encompass not only computers having differing architectures such as single/multi controller architectures and sequencers/parallel architectures, but also specialised circuits such as field programmable gate arrays FPGA, application specify circuits ASIC, signal processing devices and other devices. References to computer program, instructions, code etc. should be understood to express software for a programmable controller firmware such as the programmable content of a hardware device as instructions for a controller or configured or configuration settings for a fixed function device, gate array, programmable logic device, etc.

By way of example, and not limitation, such “computer-readable storage medium” may mean a non-transitory computer-readable storage medium which may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage, or other magnetic storage devices, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. An exemplary non-transitory computer-readable storage medium is an optical storage disk such as a CD. Also, any connection is properly termed a “computer-readable medium”. For example, if instructions are transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSF), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSF, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. It should be understood, however, that “computer-readable storage medium” and data storage media do not include connections, carrier waves, signals, or other transient media, but are instead directed to non-transient, tangible storage media. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of “computer-readable medium”.

Instructions may be executed by one or more controllers, such as one or more digital signal controllers (DSPs), general purpose microcontrollers, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Accordingly, the term “controller,” as used herein may refer to any of the foregoing structure or any other structure suitable for implementation of the techniques described herein. In addition, in some aspects, the functionality described herein maybe provided within dedicated hardware and/or software modules. Also, the techniques could be fully implemented in one or more circuits or logic elements.

If desired, the different steps discussed herein may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the above-described steps maybe optional or maybe combined.

It will be evident to persons skilled in the art that variations and modifications of the above specific disclosures can be made without departing from the scope of the following claims.

Claims

1. A computer-implemented method of controlling at least one electric drive apparatus of a vehicle when the vehicle is travelling on an inclined surface, comprising: determining a steepness of an inclined surface on which the vehicle is travelling; determining, based on the determined steepness of the inclined surface, at least one of a drive torque to apply to at least one wheel of the vehicle and a regenerative braking torque to apply to at least one wheel of the vehicle; and applying, by the at least one electric drive apparatus to at least one wheel of the vehicle, at least one of the determined drive torque and the determined regenerative braking torque.

2. The method of claim l, further comprising: based on the determined steepness of the inclined surface, determining a maximum torque value; and in determining the drive torque to apply to at least one wheel of the vehicle, limiting the determined drive torque to a value lower than or equal to the determined maximum torque value.

3. The method of claim 2, wherein determining the maximum torque value comprises: determining the maximum torque value as being inversely proportional to a value indicative of the determined steepness of the inclined surface.

4. The method of any preceding claim, further comprising: based on the determined steepness of the inclined surface, determining a maximum acceleration with which the vehicle may travel up the inclined surface; and in determining the drive torque to apply to at least one wheel of the vehicle, selecting a drive torque which limits the acceleration of the vehicle to a value lower than or equal to the determined maximum acceleration.

5. The method of claim 4, wherein determining the maximum acceleration with which the vehicle may travel up the inclined surface comprises: determining the maximum acceleration as being inversely proportional to a value indicative of the determined steepness of the inclined surface.

6. The method of any preceding claim, comprising: based on the determined steepness of the inclined surface, determining a maximum speed at which the vehicle may travel down the inclined surface; and in determining the regenerative braking torque to apply to at least one wheel of the vehicle, selecting a regenerative braking torque which limits the speed of the vehicle on the inclined surface to a speed equal to or lower than the determined maximum speed.

7. The method of claim 6, wherein determining the maximum speed at which the vehicle may travel down the inclined surface comprises: determining the maximum speed as being inversely proportional to a value indicative of the determined steepness of the inclined surface.

8. The method of any preceding claim, comprising: based on the determined steepness of the inclined surface, determining a maximum acceleration with which the vehicle may travel down the inclined surface; and in determining the regenerative braking torque to apply to at least one wheel of the vehicle, selecting a regenerative braking torque which limits the acceleration of the vehicle on the inclined surface to an acceleration equal to or lower than the determined maximum acceleration.

9. The method of claim 8, wherein determining the maximum acceleration with which the vehicle may travel down the inclined surface comprises: determining the maximum acceleration as being inversely proportional to a value indicative of the determined steepness of the inclined surface.

10. The method of claim 8 or 9, wherein the acceleration of the vehicle is the acceleration due to gravity as the vehicle descends the inclined surface.

11. The method of any of claims 8 to 10, wherein the acceleration of the vehicle is the forward/rearward acceleration of the vehicle.

12. The method of any preceding claim, wherein determining the steepness of the inclined surface on which the vehicle is travelling comprises: receiving data from at least one incline determining apparatus of the vehicle; and determining, from the received data, the steepness of the inclined surface on which the vehicle is travelling.

13. The method of claim 12, wherein the at least one incline determining apparatus comprises at least one gyroscope apparatus and wherein the determining apparatus is configured to: sense an incline of a surface on which the vehicle is travelling; and generate, from the sensed incline, data indicative of a steepness of the surface.

14. The method of any preceding claim, wherein determining the drive torque to apply to at least one wheel of the vehicle further comprises: receiving, from at least one speedometer of the vehicle, data indicative of the speed of the vehicle on the inclined surface; and determining an increased or decreased drive torque based on whether the data indicates that the speed of the vehicle is respectively lower than or greater than a speed threshold value for the inclined surface.

15. The method of any preceding claim, wherein determining the drive torque to apply to at least one wheel of the vehicle further comprises: receiving data indicating a drive power being supplied to at least one wheel of the vehicle from energy being supplied by a human operating at least one human-operable actuator of the vehicle; determining the drive torque to apply to at least one wheel of the vehicle based on the drive power, indicated by the data, as being supplied by the human operating the at least one human-operable actuator.

16. The method of claim 15, wherein the at least one human-operable actuator comprises at least one foot or hand-operable pedal apparatus.

17. A computer program comprising computer executable instructions which, when executed by at least one computing apparatus, cause the at least one computing apparatus to perform the method of any preceding claim.

18. A vehicle comprising: at least one computer processor; and at least one computer memory storing computer executable instructions which, when executed by at least one computer processor, cause the at least one computing apparatus to perform the method of any preceding claim.

19. The vehicle of claim 18, wherein the vehicle is a cycle.

20. The vehicle of claim 19, wherein the cycle is an Electronically Power Assisted Cycle (EPAC).

21. The vehicle of any of claims 18 to 20, comprising the at least one drive apparatus configured to actuate at least one wheel of the vehicle, wherein the drive apparatus comprises at least one user-operable actuator for controlling operation of the drive apparatus.

22. The vehicle of any of claims 18 to 21, comprising the incline determining apparatus.

23. A vehicle system, comprising: at least one electrical drive apparatus configured to actuate at least one wheel of the vehicle; at least one incline determining apparatus configured to determine a gradient of surface on which the vehicle is currently travelling; and at least one computing apparatus configured to select an operating state of the at least one electrical drive apparatus in dependence of the gradient of the surface determined by the at least one incline determining apparatus.

24. The vehicle system of claim 23, comprising a cycle.

25. The vehicle system of claim 24, wherein the cycle comprises an Electronically Power Assisted Cycle (EPAC).

26. The vehicle system of any of claims 23 to 25, wherein the at least one computing apparatus is configured to perform the method of any of claims 1 to 16.