Wheelchair mobility system and method

[0001] This application claims the benefit of U.S. Provisional Application 60/337,994 filed Dec. 7, 2001, which is hereby incorporated by reference in its entirety.

[0002] This invention relates to the adaptation of a wheelchair for use as a driver's seat in a vehicle, wherein the wheelchair includes non-mechanical controls adaptable for driving the vehicle.

[0003] Persons confined to wheelchairs face many obstacles to mobility. Enabling a wheelchair-bound person to drive a vehicle, such as an automobile, has proven to be a challenge. Wheelchair controls typically must be custom designed, often at significant cost to the user. Significant time and effort may be expended by the user in learning to master the use of such controls. Even with the most technologically advanced wheelchair and wheelchair controls that permit a user to remain in the wheelchair and position him or her self in a vehicle as a driver, the user must then maneuver a separate set of the vehicle's own controls in order to then drive the vehicle. These separate controls may need to be modified to accommodate specific physical limitations of the wheelchair bound person. The wheelchair controls may interfere with the person's ability to utilize the separate vehicle controls.

[0004] This invention serves the primary purpose of increasing the mobility of a wheelchair bound person by allowing him to utilize his wheelchair and its controls as a driver's seat and controls of a separate vehicle.

[0005] The invention eliminates the challenge of exiting a wheelchair and repositioning into a separate driver's seat. The person is able to drive a vehicle, such as an automobile, with the wheelchair essentially becoming the driver's seat.

[0006] The invention eliminates the cost of purchasing, customizing and training to use separate specialized controls for the wheelchair-bound person in the vehicle. The wheelchair controls are able to control and drive both the wheelchair independently of the vehicle and the vehicle when the wheelchair is mounted thereon.

[0007] The invention permits recharging of the wheelchair battery by the vehicle battery, the alternator or the vehicle power system when the wheelchair is connected to the vehicle. This convenient feature saves time by eliminating the need for connecting to a separate charging mechanism.

[0008] Accordingly, a mobility system of a vehicle has a drive-by-wire control apparatus, including a drive-by-wire connector port, and a wheelchair that is removably mountable to the vehicle and has a connector that is operatively connectable to an operator interface and operably and removably connectable with the connector port. When the connector is interfitted with the connector port, the operator interface may be used to drive the vehicle when the wheelchair is mounted in the vehicle. When the connector is disconnected from the connector port and the wheelchair is removed from the vehicle, the operator interface may be used to drive the wheelchair. In the above mobility system wherein the vehicle has a power source and the wheelchair has a battery that may be engaged with the power source so that the power source recharges the battery when the wheelchair is mounted in the vehicle with the connector connected to the connector port.

[0009] A more specific embodiment of the mobility system is a vehicle and a wheelchair wherein the vehicle has a frame, at least three wheels that are operable with respect to the frame, and steering, braking and energy conversion systems that are mounted with respect to the frame and that are responsive to non-mechanical control signals. A connector port is also mounted with respect to the frame and operably connected to the steering, braking and energy conversion systems. The vehicle has structure forming a groove that is substantially fixed with respect to the frame. The wheelchair has a motor and a locator that is interfittable with the structure forming a groove to position the wheelchair with respect to the vehicle as a driver's seat. The wheelchair has an operator interface that allows the wheelchair to be driven independently of the vehicle through the motor. The operator interface also drives the vehicle through the connector port when the locator on the vehicle is interfitted with the structure forming a groove on the vehicle. The wheelchair has a battery for powering the wheelchair when the operator interface is operable for driving the wheelchair independently of the vehicle. The battery has a connector for interconnecting the battery with a power source in the energy conversion system of the vehicle to recharge the battery when the operator interface is operable for driving the vehicle.

[0010] The invention also provides a wheelchair that is adapted for multiple uses as a wheelchair and as a driver's seat for a drivable vehicle. The wheelchair has a chair for supporting a person, a wheel that is connected to the chair and that supports and motivates the chair, and a motor for driving the wheel. The wheelchair also has an operator interface in a drivable relationship by a person in the chair and a controllable relationship to the motor. The wheelchair has a connector that is selectively connectable with the motor to control the wheelchair or with the vehicle to drive the vehicle. The invention also includes the wheelchair described above wherein it has a battery for powering the motor and the battery has a connector that is selectively interconnectable with the vehicle to recharge the battery when the operator interface is interconnected with the vehicle.

[0011] The invention also includes a method of enabling a vehicle to be driven from a wheelchair. An operator interface is provided on the wheelchair that is usable for driving the wheelchair. Another step of the method is providing access on the vehicle for receiving the wheelchair onboard the vehicle. A further step of the method is providing an operator interface connector configured to be connectable between the operator interface and the vehicle when the wheelchair is onboard the vehicle so that the operator interface is usable for driving the vehicle. The invention also contemplates the above method with the additional step of providing a locator on the wheelchair and a second locator on the vehicle for sufficiently intermitting the wheelchair and the vehicle when the wheelchair is received onboard the vehicle so that the wheelchair is located with respect to the vehicle. The invention further contemplates that the locators may be accessible to the user of the wheelchair, permitting the user to interfit the wheelchair and the vehicle with the locators. Finally, the method contemplates the above steps with the additional step of providing a mechanism for securing the wheelchair to the vehicle. The invention contemplates that the mechanism may be accessible to the user of the wheelchair, permitting the user to secure the wheelchair to the vehicle.

[0012] The invention also includes a method for the wheelchair-bound to drive a vehicle. One step of the method is driving a wheelchair through an operator interface that controls at least one of the wheelchair's steering, accelerating, decelerating and braking functions. Another step of the method is accessing the vehicle while wheelchair-bound. This step may include controlling structure on the vehicle that facilitates the access. It may also include affixing the wheelchair in a fixed relation to the vehicle. Another step of the method is connecting the operator interface to the vehicle in a manner for controlling at least one of the vehicle's steering, accelerating, decelerating and braking.

[0013] The above objects, features, and advantages, and other objects, features, and advantages, of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings.

[0014] FIG. 1 is a side schematic illustration of a mobility system in accordance with an embodiment of the invention, the wheelchair having a battery connectable to a power source in the vehicle and a first locator on the vehicle being in the form of structure forming a groove.

[0015] FIG. 2 is a schematic illustration of a steering system for use with the mobility system of FIG. 1;

[0016] FIG. 3 is a schematic illustration of an alternative steering system for use with the mobility system of FIG. 1;

[0017] FIG. 4 is a schematic illustration of a braking system for use with the mobility system of FIG. 1;

[0018] FIG. 5 is a schematic illustration of an alternative braking system for use with the mobility system of FIG. 1;

[0019] FIG. 6 is a schematic illustration of an energy conversion system for use with the mobility system of FIG. 1;

[0020] FIG. 7 is a schematic illustration of an alternative energy conversion system for use with the mobility system of FIG. 1;

[0021] FIG. 8 is a side schematic illustration of a wheelchair in accordance with another embodiment of the invention, the wheelchair having a battery attached to a connector;

[0022] FIG. 9 is a flow diagram illustrating a method of enabling a vehicle to be driven from a wheelchair in accordance with an embodiment of the invention, the method including the step of providing a locator on the wheelchair and another locator on the vehicle for interfitting the wheelchair and the vehicle; and

[0023] FIG. 10 is a flow diagram illustrating a method for the wheelchair-bound to drive a vehicle through an interface on the wheelchair that also controls the wheelchair in accordance with the invention.

[0024] Referring to FIG. 1, a mobility system 10 in accordance with the invention includes a vehicle 12 and a wheelchair 14. The vehicle 12 includes a frame 15 having four wheels 16, 17, 18, 19 that are operable with respect to the frame 15. The vehicle 12 is preferably an automobile but the invention also contemplates that the vehicle may be a tractor, forklift, or other industrial vehicle. Those skilled in the art will recognize materials and fastening methods suitable for attaching the wheels 16, 17, 18 and 19 to the frame 15.

[0025] The vehicle 12 further includes a steering system 20, a braking system 22 and an energy conversion system 24, each of which is mounted with respect to the frame 15 and responsive to non-mechanical control signals. The energy conversion system 24 is connected to a power source 26. Embodiments of such systems are described subsequently with respect to FIG. 4 through FIG. 9.

[0026] The structural frame 15 provides a rigid structure to which the steering system 20, braking system 22 and energy conversion system 24 as well as the wheels 16, 17, 18, 19 are mounted, as shown in FIG. 1, and is configured to support an attached body such as an automotive body. A person of ordinary skill in the art will recognize that the structural frame 15 can take many different forms. For example, the structural frame 15 can be a traditional automotive frame having two or more longitudinal structural members spaced a distance apart from each other, with two or more transverse structural members spaced apart from each other and attached to both longitudinal structural members at their ends. Alternatively, the structural frame may also be in the form of a belly pan, wherein integrated rails and cross members are formed in sheets of metal or other suitable material, with other formations to accommodate various system components. The structural frame may also be integrated with various vehicle components.

[0027] The vehicle 12 includes a connector port 28, also referred to as a drive-by-wire connector port, that is mounted with respect to the frame 15 and operably connected to the steering system 20, the braking system 22, and the energy conversion system 24. Persons skilled in the art will recognize various methods for mounting the connector port 28 to the frame 15. In the preferred embodiment, the connector port is located on the top face of the frame 15, in close proximity to the wheelchair 14. Various embodiments of the manner for operably connecting the connector port 28 to the steering system 20, the braking system 22, and the energy conversion system 24 are described subsequently with respect to FIG. 2 through FIG. 7.

[0028] The wheelchair 14 shown in FIG. 1 includes a motor 30 for driving the wheelchair 14. Prior art includes many representations of motorized wheelchairs; those skilled in the art will recognize many methods of attaching a motor 30 to the wheelchair 14 such that the motor 30 will power the wheelchair 14 when the wheelchair 14 is independent of the vehicle 12.

[0029] The wheelchair 14 includes a locator 32, also referred to herein as a second locator. The locator 32 is designed to be interfittable with a first locator 34 that is substantially fixed with respect to the frame 15. The location and design of the locator 32 on the wheelchair 14 and the first locator 34 on the frame 15 are such that, once interfitted, the wheelchair 14 is positioned with respect to the vehicle 12 as a driver's seat. The first locator 34 is structure forming a groove 37 in the embodiment depicted in FIG. 1. When the first locator 34 is structure forming a groove 37, the locator 32 could be a portion of the wheel 13 on the wheelchair 14. Ideally, the width, length and depth of the groove 37 are designed to permit a large enough part of the wheel 13 to rest in the groove 37 such that the wheelchair 14 is secured to the frame 15. Those skilled in the art will recognize various other designs for a locator 32 on the wheelchair capable of interfitting with the first locator 34 to securely position the wheelchair 14 on the vehicle as a driver's seat. A locking clamp attached to the frame 15 that secures to a portion of the wheelchair 14, one or more magnets attached to the wheelchair 14, aligned with a number of magnets of opposing polar forces on the frame 15, or a releaseably locking belt, similar to a seatbelt, attached to the frame 15 and designed to secure a portion of the wheelchair 14, are examples of locator and second locator designs that may be feasible. Another embodiment would include a first locator in the form of a seat on the vehicle with the second locator being the chair portion of the wheelchair such that when the wheelchair is onboard the vehicle, the chair portion fits on top of the seat to secure the chair. This embodiment would permit the wheelchair wheels to be designed to disengage from the chair portion once it is positioned on the seat. In this embodiment, the operator interface would be affixed to the chair portion of the wheelchair such that it is readily accessible to control the vehicle once the chair portion is engaged with the seat.

[0030] A secondary restraining device, such as a clamp attached to the frame 15 may be employed in conjunction with the groove 37 to afford greater securement. In the embodiment depicted in FIG. 1, a locking clamp 33 is attached to the frame. When the locator 32 is interfitted with the first locator 34, the locking clamp 33 automatically locks the wheel 13 to the frame 15.

[0031] The wheelchair includes an operator interface 36, that is operable for driving the wheelchair 14 independently of the vehicle 12 through the motor 30 and operable for driving the vehicle 12 through the connector port 28 when the locator 32 on the wheelchair 14 is interfitted with the first locator 34 on the frame 15. The invention may also include a wheelchair that has no motor but has a vehicle attachment interface only for steering purposes. The operator interface 36 may be fixed with respect to the wheelchair 14 or movable in relation thereto. In the preferred embodiment of FIG. 1, it is represented as being fixed to the wheelchair 14. In FIG. 1, the operator interface 36 is depicted as being selectively connected to the connector port 28 via a connector wire 41 for transmitting electrical signals from the operator interface 36 to a connector 42 and to the connector port 28 when the connector 42 is interfitted therewith. Although the operator interface 36 is shown as connected only to the steering system 20, the braking system 22 and the energy conversion system 24, it could conceivably be connected to control a multitude of vehicle systems such as climate control systems, and video or audio systems.

[0032] Those skilled in the art will recognize various designs for an operator interface 36 capable of transforming directional input from a wheelchair occupant into an electrical signal to be transmitted either to the motor 30 of the wheelchair or to the connector port 28 of the vehicle if the operator interface is operably connected to the connector port 28. The operator interface 36 could include one or more manual joysticks, and may further include a touch screen or keyboard design. A touch screen and keyboard design employed in combination could conceivably be converted to an Internet access device when the interface is not being used with either the wheelchair 14 or the vehicle 12 in drive mode. Prior art teaches controls for various devices that are responsive to head movements, eye movements or breathing motions of a disabled person. The interface may include any of these designs and other designs.

[0033] The wheelchair 14 includes a battery 38 designed for powering the wheelchair 14 when the operator interface 36 is operable for driving the wheelchair 14 independently of the vehicle 12 through the motor 30. The battery 38 has a connector wire 40 for interconnecting the battery through the connector 42 and the connector port 28 to the power source 26 in the energy conversion system 24. In FIG. 1, the connector wire 40 is depicted as connecting the connector 42 through the operator interface 36 and the connector wire 41. When the connector wire 40 is operably connected to the power source 26, the battery is recharged by the power source 26.

[0034] The connector port 28 of the preferred embodiment may perform multiple functions, or select combinations thereof. First, the connector port 28 may function as an electrical power connector, i.e., it may be configured to transfer electrical energy generated by components on the vehicle 12 to the operator interface 36 or other non-frame destination. Second, the connector port 28 may function as a control signal receiver, i.e., a device configured to transfer non-mechanical control signals from a non-vehicle source, such as the operator interface 36, to controlled systems including the steering system 20, the braking system 22, and the energy conversion system 24. Third, the connector port 28 may function as a feedback signal conduit through which feedback signals are made available to a vehicle driver. Fourth, the connector port 28 may function as an external programming interface through which software containing algorithms and data may be transmitted for use by controlled systems. Fifth, the connector port 28 may function as an information conduit through which sensor information and other information is made available to a vehicle driver. The connector port 28 may thus function as a communications and power umbilical port through which all communications between the vehicle 12 and the attached operator interface 36 and other attachments to the frame are transmitted. The connector port 28 is essentially an electrical connector. Electrical connectors include devices configured to operably connect one or more electrical wires with other electrical wires. The wires may be spaced a distance apart to avoid any one wire causing signal interference in another wire operably connected to an electrical connector or for any reason that wires in close proximity may not be desirable.

[0035] The steering system 20 is housed in the vehicle 12 and is operably connected to the front wheels 16, 17. Preferably, the steering system 20 is responsive to non-mechanical control signals. In the preferred embodiment, the steering system 20 is by-wire. A by-wire system is characterized by control signal transmission in electrical form. In the context of the present invention, by-wire systems, or systems that are controllable by-wire, include systems configured to receive control signals in electronic form via a control signal receiver, and respond in conformity to the electronic control signals.

[0036] FIG. 2 is a schematic illustration of a steering system for use with the mobility system of FIG. 1. The by-wire steering system 20 of the preferred embodiment includes a steering control unit 44, and a steering actuator 46. Sensors 48 are located on the vehicle 12 and transmit sensor signals 50 carrying information concerning the state or condition of the vehicle 12 and its component systems. The sensors 48 may include position sensors, velocity sensors, acceleration sensors, pressure sensors, force and torque sensors, flow meters, temperature sensors, etc. The steering control unit 44 receives and processes sensor signals 50 from the sensors 48 and electrical steering control signals 52 from the connector port 28, and generates steering actuator control signals 54 according to a stored algorithm. A control unit typically includes a microprocessor, ROM and RAM and appropriate input and output circuits of a known type for receiving the various input signals and for outputting the various control commands to the actuators. Sensor signals 50 may include yaw rate, lateral acceleration, angular wheel velocity, tie-rod force, steering angle, chassis velocity, etc.

[0037] The steering actuator 46 is operably connected to the front wheels 16, 17 and configured to adjust the steering angle of the front wheels 16, 17 in response to the steering actuator control signals 54. Actuators in a by-wire system transform electronic control signals into a mechanical action or otherwise influence a system's behavior in response to the electronic control signals. Examples of actuators that may be used in a by-wire system include electromechanical actuators such as electric servomotors, translational and rotational solenoids, magnetorheological actuators, electrohydraulic actuators, and electrorheological actuators. Those skilled in the art will recognize and understand mechanisms by which the steering angle is adjusted. In the preferred embodiment, the steering actuator 46 is an electric drive motor configured to adjust a mechanical steering rack.

[0038] Referring to FIG. 2, the preferred embodiment of the vehicle 12 is configured such that it is steerable by any source of compatible electrical steering control signals 52 connected to the connector port 28. The connector port 28 interfits with the connector 42 at the connector interface 53. FIG. 2 depicts a steering transducer 56 located within the operator interface 36 and connected to a complementary connector 42. Transducers convert the mechanical control signals of a vehicle driver to non-mechanical control signals. When used with a by-wire system, transducers convert the mechanical control signals to electrical control signals usable by the by-wire system. A vehicle driver inputs control signals in mechanical form by turning a wheel, gripping or turning a handle or handles, using head or eye movements, using controlled breathing movements (puffs or sucks of air), pressing a button, or the like. Transducers utilize sensors, typically position and force sensors, to convert the mechanical input to an electrical signal.

[0039] The complementary connector 42 is coupled with the connector port 28 of the connector interface 53. The steering transducer 56 converts vehicle driverinitiated mechanical steering control signals 60 to electrical steering control signals 52 which are transmitted via the connector port 28 to the steering control unit 44. In the preferred embodiment, the steering control unit 44 generates steering feedback signals 62 for use by a vehicle driver and transmits the steering feedback signals 62 through the connector port 28. Some of the sensors 48 monitor linear distance movement of a steering rack and vehicle speed. This information is processed by the steering control unit 44 according to a stored algorithm to generate the steering feedback signals 62.

[0040] In the context of the present invention, a by-wire system may be an actuator connected directly to the connector port 28. An alternative by-wire steering system 20 within the scope of the claimed invention is depicted schematically in FIG. 3, wherein like reference numbers refer to like components from FIG. 2. A steering actuator 46 configured to adjust the steering angle of the front wheels 16, 17 is connected directly to the connector port 28. In this embodiment, a steering control unit 44 and a steering transducer 56 may be located in the operator interface 36. The steering transducer 56 would transmit electrical steering control signals 52 to the steering control unit 44, and the steering control unit 44 would transmit steering actuator control signals 54 to the steering actuator 46 via the connector port 28. Sensors 48 positioned on the vehicle 12 transmit sensor signals 50 to the steering control unit 44 via the connector port 28 and the complementary connector 42.

[0041] Examples of steer-by-wire systems are described in U.S. Pat. Nos. 6,176,341, issued Jan. 23, 2001 to Delphi Technologies, Inc; 6,208,923, issued Mar. 27, 2001 to Robert Bosch GmbH; 6,219,604, issued Apr. 17, 2001 to Robert Bosch GmbH; 6,318,494, issued Nov. 20, 2001 to Delphi Technologies, Inc.; 6,370,460, issued Apr. 9, 2002 to Delphi Technologies, Inc.; and 6,394,218, issued May 28, 2002 to TRW Fahrwerksysteme GmbH & Co. KG; which are hereby incorporated by reference in their entireties.

[0042] The steer-by-wire system described in U.S. Pat. No. 6,176,341 includes a position sensor for-sensing angular position of a road wheel, a hand-operated steering wheel for controlling direction of the road wheel, a steering wheel sensor for sensing position of the steering wheel, a steering wheel actuator for actuating the hand-operated steering wheel, and a steering control unit for receiving the sensed steering wheel position and the sensed road wheel position and calculating actuator control signals, preferably including a road wheel actuator control signal and a steering wheel actuator control signal, as a function of the difference between the sensed road wheel position and the steering wheel position. The steering control unit commands the road wheel actuator to provide controlled steering of the road wheel in response to the road wheel actuator control signal. The steering control unit further commands the steering wheel actuator to provide feedback force actuation to the hand-operated steering wheel in response to the steering wheel control signal. The road wheel actuator control signal and steering wheel actuator control signal are preferably scaled to compensate for difference in gear ratio between the steering wheel and the road wheel. In addition, the road wheel actuator control signal and steering wheel actuator control signal may each have a gain set so that the road wheel control actuator signal commands greater force actuation to the road wheel than the feedback force applied to the steering wheel.

[0043] The steer-by-wire system described in U.S. Pat. No. 6,176,341 preferably implements two position control loops, one for the road wheel and one for the hand wheel. The position feedback from the steering wheel becomes a position command input for the road wheel control loop and the position feedback from the road wheel becomes a position command input for the steering wheel control loop. A road wheel error signal is calculated as the difference between the road wheel command input (steering wheel position feedback) and the road wheel position. Actuation of the road wheel is commanded in response to the road wheel error signal to provide controlled steering of the road wheel. A steering wheel error signal is calculated as the difference between the steering wheel position command (road wheel position feedback) and the steering wheel position. The hand-operated steering wheel is actuated in response to the-steering wheel error signal to provide force feedback to the hand-operated steering wheel.

[0044] The steering control unit of the '341 system could be configured as a single processor or multiple processors and may include a general-purpose microprocessor-based controller, that may include a commercially available off-the-shelf controller. One example of a controller is Model No. 87C196CA microcontroller manufactured and made available from Intel Corporation of Delaware. The steering control unit preferably includes a processor and memory for storing and processing software algorithms, has a clock speed of 16 MHz, two optical encoder interfaces to read position feedbacks from each of the actuator motors, a pulse width modulation output for each motor driver, and a 5-volt regulator.

[0045] U.S. Pat. No. 6,370,460 describes a steer-by-wire control system comprising a road wheel unit and a steering wheel unit that operate together to provide steering control for the vehicle operator. A steering control unit may be employed to support performing the desired signal processing. Signals from sensors in the road wheel unit, steering wheel unit, and vehicle speed are used to calculate road wheel actuator control signals to control the direction of the vehicle and steering wheel torque commands to provide tactile feedback to the vehicle operator. An Ackerman correction may be employed to adjust the left and right road wheel angles correcting for errors in the steering geometry to ensure that the wheels will track about a common turn center.

[0046] Referring again to FIG. 1, a braking system 22 is mounted to the frame 15 and is operably connected to the wheels 16, 17, 18, 19. The braking system 22 is configured to be responsive to non-mechanical control signals. In the preferred embodiment, the braking system 22 is by-wire, as depicted schematically in FIG. 4, wherein like reference numbers refer to like components from FIGS. 2 and 3. Sensors 48 transmit sensor signals 50 carrying information concerning the state or condition of the vehicle 12 and its component systems to a braking control unit 64. The braking control unit 64 is connected to the connector port 28 and is configured to receive electrical braking control signals 66 via the connector port 28. The braking control unit 64 processes the sensor signals 50 and the electrical braking control signals 66 and generates braking actuator control signals 68 according to a stored algorithm. The braking control unit 64 then transmits the braking actuator control signals 68 to braking actuators 70, 72, 74, 76 which act to reduce the angular velocity of the wheels 16, 17, 18, 19. Those skilled in the art will recognize the manner in which the braking actuators 70, 72, 74, 76 act on the wheels 16, 17, 18, 19. Typically, actuators cause contact between friction elements, such as pads and disc rotors. Optionally, an electric motor may function as a braking actuator in a regenerative braking system.

[0047] The braking control unit 64 may also generate braking feedback signals 78 for use by a vehicle driver and transmit the braking feedback signals 78 through the connector port 28. In the preferred embodiment, the braking actuators 70, 72, 74, 76 apply force through a caliper to a rotor at each wheel. Some of the sensors 48 measure the applied force on each caliper. The braking control unit 64 uses this information to ensure synchronous force application to each rotor.

[0048] Referring again to FIG. 4, the preferred embodiment of the vehicle 12 is configured such that the braking system 22 is responsive to any source of compatible electrical braking control signals 66. A braking transducer 80 may be located in the operator interface 36 and connected to a complementary connector 42 interfitted with the connector port 28 at the connector interface 53. The braking transducer 80 converts vehicle driver-initiated mechanical braking control signals 82 into electrical form and transmits the electrical braking control signals 66 to the braking control unit via the connector port 28. In the preferred embodiment, the braking transducer 80 includes two hand-grip type assemblies. The braking transducer 80 includes sensors that measure both the rate of applied pressure and the amount of applied pressure to the hand-grip assemblies, thereby converting mechanical braking control signals 82 to electrical braking control signals 66. The braking control unit 64 processes both the rate and amount of applied pressure to provide both normal and panic stopping.

[0049] An alternative brake-by-wire system 22 within the scope of the claimed invention is depicted in FIG. 5, wherein like reference numbers refer to like components from FIGS. 2-4. The braking actuators 70, 72, 74, 76 and sensors 48 are connected directly to the connector port 28. In this embodiment, a braking control unit 64 may be located within the operator interface 36. A braking transducer 80 within the operator interface 36 transmits electrical braking control signals 66 to the braking control unit 64, and the braking control unit 64 transmits braking actuator signals 68 to the braking actuators 70, 72, 74, 76 via the connector 42 and to the connector port 28.

[0050] Examples of brake-by-wire systems are described in U.S. Pat. Nos. 5,366,281, issued Nov. 22, 1994 to General Motors Corporation; 5,823,636, issued Oct. 20, 1998 to General Motors Corporation; 6,305,758, issued Oct. 23, 2001 to Delphi Technologies, Inc.; and 6,390,565, issued May 21, 2002 to Delphi Technologies, Inc.; which are hereby incorporated by reference in their entireties.

[0051] The system described in U.S. Pat. No. 5,366,281 includes an input device for receiving mechanical braking control signals, a brake actuator and a control unit coupled to the input device and the brake actuator. The control unit receives brake commands, or electrical braking control signals, from the input device and provides actuator commands, or braking actuator control signals, to control current and voltage to the brake actuator. When a brake command is first received from the input device, the control unit outputs, for a first predetermined time period, a brake torque command to the brake actuator commanding maximum current to the actuator. After the first predetermined time period, the control unit outputs, for a second predetermined time period, a brake torque command to the brake actuator commanding voltage to the actuator responsive to the brake command and a first gain factor. After the second predetermined time period, the control unit outputs the brake torque command to the brake actuator commanding current to the actuator responsive to the brake command and a second gain factor, wherein the first gain factor is greater than the second gain factor and wherein brake initialization is responsive to the brake input.

[0052] U.S. Pat. No. 6,390,565 describes a brake-by-wire system that provides the capability of both travel and force sensors in a braking transducer connected to a brake apply input member such as a brake pedal and also provides redundancy in sensors by providing the signal from a sensor responsive to travel or position of the brake apply input member to a first control unit and the signal from a sensor responsive to force applied to a brake apply input member to a second control unit. The first and second control units are connected by a bi-directional communication link whereby each controller may communicate its received one of the sensor signals to the other control unit. In at least one of the control units, linearized versions of the signals are combined for the generation of first and second brake apply command signals for communication to braking actuators. If either control unit does not receive one of the sensor signals from the other, it nevertheless generates its braking actuator control signal on the basis of the sensor signal provided directly to it. In a preferred embodiment of the system, a control unit combines the linearized signals by choosing the largest in magnitude.

[0053] FIG. 6 is a schematic illustration of an energy conversion system 24 for use with the mobility system depicted in FIG. 1. The energy conversion system 24 includes an energy converter 25 that converts the energy stored in an energy storage system 27 to mechanical energy that propels the vehicle 12. In the preferred embodiment, depicted in FIG. 6, the energy converter 25 is operably connected to a traction motor 83. The energy converter 25 converts chemical energy into electrical energy, and the traction motor 83 converts the electrical energy to mechanical energy, and applies the mechanical energy to rotate the front wheels 16, 17. Those skilled in the art will recognize many types of energy converters 25 that may be employed within the scope of the present invention.

[0054] The energy conversion system 24 is configured to respond to non-mechanical control signals. The energy conversion system 24 of the preferred embodiment is controllable by-wire, as depicted in FIG. 6. An energy conversion system control unit 84 is connected to the connector port 28 from which it receives electrical energy conversion system control signals 86, and sensors 48 from which it receives sensor signals 50 carrying information about various vehicle conditions. In the preferred embodiment, the information conveyed by the sensor signals 50 to the energy conversion system control unit 84 includes vehicle velocity, electrical current applied, rate of acceleration of the vehicle, and motor shaft speed to ensure smooth launches and controlled acceleration. The energy conversion system control unit 84 is connected to an energy conversion system actuator 88, and transmits energy conversion system actuator control signals 90 to the energy conversion system actuator 88 in response to the electrical energy conversion system control signals 86 and sensor signals 50 according to a stored algorithm. The energy conversion system actuator 88 acts on the energy conversion system 24 or traction motor 83 to adjust energy output. Those skilled in the art will recognize the various methods by which the energy conversion system actuator 88 may adjust the energy output of the energy conversion system.

[0055] An energy conversion system transducer 92 may be located in the operator interface 36 and connected to a complementary connector 42 engaged with the connector port 28 at the connector interface 53. The energy conversion system transducer 92 is configured to convert mechanical energy conversion system control signals 94 to electrical energy conversion system control signals 86.

[0056] In another embodiment of the invention, as shown schematically in FIG. 7, wherein like reference numbers refer to like components from FIGS. 2-6, wheel motors 96, also known as wheel hub motors, are positioned at each of the four wheels 16, 17, 18, 19. Optionally, wheel motors 96 may be provided at only the front wheels 16, 17 or only the rear wheels 18, 19. The use of wheel motors 96 reduces the height of the vehicle 12 compared to the use of traction motors, and therefore may be desirable for certain uses.

[0057] Referring to FIG. 8, a wheelchair 96 in accordance with the invention includes a chair 98 for supporting a person and wheels 102 connected to the chair 98 for supporting and motivating the chair 98. A motor 104 is mounted on the wheelchair 96 and operably connected to the wheels 102 for driving the wheels 102. An operator interface 106 is drivable by the person in the chair 98. The operator interface 106 is in a controllable relationship to the motor 104. The operator interface 106 is connectable with the motor 104 to drive the wheels 102 and control the chair 98. Alternatively, the operator interface 106 is designed to be connectable with another vehicle to drive the vehicle. This interconnectablility is depicted in FIG. 8 with a connector wire 108 connected at one end to the operator interface 106 and connectable at the other end through a connector plug 109 either to the motor 104 or to a vehicle. A battery 110 is mounted on the wheelchair 96. The battery powers the motor 104 to drive the wheels 102 when the operator interface 106 is used to control the motor. The battery has a connector wire 112 that is selectively connectable to a vehicle when the operator interface 106 is used to drive such vehicle. When the connector wire 112 is connected to a vehicle, the battery is recharged. Those skilled in the art will recognize a variety of ways to accomplish recharging of the battery 110 by the vehicle. FIG. 8 shows an embodiment wherein the connector wire 112 is connectable to a vehicle through the operator interface 106 and the connector plug 109 that connects the operator interface 106 to a vehicle. Those skilled in the art will recognize alternative means for connecting the connector wire 112 to a vehicle.

[0058] Additionally, the invention provides a multiple step process for enabling a vehicle to be driven from a wheelchair. One embodiment of this process 111 is depicted in FIG. 9. One step 114 is providing an operator interface on a wheelchair that is usable for driving the wheelchair. The operator interface could be one of a number of designs. It could include one or more manual joysticks, a touchscreen or keyboard design, or controls that are responsive to head movements, eye movements or breathing motions of a wheelchair-bound person. Those skilled in the art will recognize many different forms that the operator interface may take. Another step 116 is providing access on a vehicle for receiving the wheelchair onboard the vehicle. Access could include a ramp or lift. It may encompass special design features of the vehicle such as a wider door or a structural mechanism incorporated into the vehicle that enables wheelchair entry. Another optional step 118 depicted in FIG. 9 is providing a locator on the wheelchair and a second locator on the vehicle that are accessible to the user of the wheelchair, permitting the user to interfit the wheelchair and the vehicle with the locators when the wheelchair is onboard the vehicle so that the wheelchair is located with respect to the vehicle. The invention also includes this step when the locators are not accessible to the user but may nevertheless be used, by another person or otherwise, to locate the wheelchair with respect to the vehicle. Another optional step 120 is providing a mechanism for securing the wheelchair to the vehicle that is accessible to the user of the wheelchair, permitting the user to secure the wheelchair to the vehicle. The invention also encompasses this optional step wherein the mechanism provided for securing the wheelchair to the vehicle is not accessible to the user of the wheelchair. In that case, another person or some other mechanism would be necessary to enable securement. Preferably, the mechanism would be designed to accommodate a wide variety of different wheelchair designs. Finally, FIG. 9 depicts another step 122 of the method providing an operator interface connector connectable between the operator interface and the vehicle when the wheelchair is onboard the vehicle so that the operator interface is usable for driving the vehicle. The above discussion of the mobility system depicted in FIG. 1 provides an example of an operator interface designed to connect to and control a vehicle that includes by-wire steering, braking and energy conversion. The connection mechanism discussed with respect to that system is an example of an operator interface connector covered by step 122. Performing steps 114 to 122 provides a method that allows a wheelchair with an operator interface to be attached to a vehicle, with the operator interface being usable to drive the vehicle.

[0059] The invention also provides a method 123 for the wheelchair-bound to drive a vehicle. This method is depicted in FIG. 10. One step 124 of the method is driving a wheelchair through an operator interface that controls at least one of the wheelchair's steering, accelerating, decelerating and braking functions. Another step 126 of the method is accessing the vehicle while wheelchair-bound wherein there is controlling structure on the vehicle that facilitates the access and including affixing the wheelchair in a fixed relation to the vehicle. The method also includes accessing the vehicle without any controlling structure on the vehicle and where the wheelchair is not necessarily fixed in relation to the vehicle. For instance, accessing the vehicle could include simply entering the vehicle via a ramp located adjacent to the vehicle. Another step 128 of the method is connecting the operator interface to the vehicle in a manner for controlling at least one of the vehicle's steering, accelerating, decelerating and braking. The above discussion of the mobility system depicted in FIG. 1 provides an example of a connection mechanism (connector wire 41, connector 42 and connector port 28) that would enable an operator interface on a wheelchair to control a vehicle. Performing steps 124 to 128 results in driving a vehicle from a wheelchair using an operator interface on the wheelchair that also drives the wheelchair.

[0060] While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the scope of the invention within the scope of the appended claims.