Patent Publication Number: US-6712164-B2

Title: Vehicle having systems responsive to non-mechanical control signals

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Applications Nos. 60/314,501 and 60/337,994, filed Aug. 23, 2001 and Dec. 7, 2001, both of which are hereby incorporated by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     This invention relates to vehicle chassis and bodies. 
     BACKGROUND OF THE INVENTION 
     Mobility, being capable of moving from place to place or of moving quickly from one state to another, has been one of the ultimate goals of humanity throughout recorded history. The automobile has likely done more in helping individuals achieve that goal than any other development. Since its inception, societies around the globe have experienced rates of change in their manner of living that are directly related to the percentage of motor vehicle owners among the population. 
     Prior art automobiles and light trucks include a body, the function of which is to contain and protect passengers and their belongings. Bodies are connected to the numerous mechanical, electrical, and structural components that, in combination with a body, comprise a fully functional vehicle. The nature of the prior art connections between a vehicle body and vehicular componentry may result in certain inefficiencies in the design, manufacture, and use of vehicles. Three characteristics of prior art body connections that significantly contribute to these inefficiencies are the quantity of connections; the mechanical nature of many of the connections; and the locations of the connections on the body and on the componentry. 
     In the prior art, the connections between a body and componentry are numerous. Each connection involves at least one assembly step when a vehicle is assembled; it is therefore desirable to reduce the number of connections to increase assembly efficiency. The connections between a prior art body and prior art vehicular componentry include multiple load-bearing connectors to physically fasten the body to the other components, such as bolts and brackets; electrical connectors to transmit electrical energy to the body from electricity-generating components and to transmit data from sensors that monitor the status of the componentry; mechanical control linkages, such as the steering column, throttle cable, and transmission selector; and ductwork and hoses to convey fluids such as heated and cooled air from an HVAC unit to the body for the comfort of passengers. 
     Many of the connections in the prior art, particularly those connections that transmit control signals, are mechanical linkages. For example, to control the direction of the vehicle, a driver sends control signals to the steering system via a steering column. Mechanical linkages result in inefficiencies, in part, because different driver locations in different vehicles require different mechanical linkage dimensions and packaging. Thus, new or different bodies often cannot use “off-the-shelf” components and linkages. Componentry for one vehicle body configuration is typically not compatible for use with other vehicle body configurations. Furthermore, if a manufacturer changes the design of a body, a change in the design of the mechanical linkage and the component to which it is attached may be required. The change in design of the linkages and components requires modifications to the tooling that produces the linkages and components. 
     The location of the connections on prior art vehicle bodies and componentry also results in inefficiencies. In prior art body-on-frame architecture, connection locations on the body are often not exposed to an exterior face of the body, and are distant from corresponding connections on the componentry; therefore, long connectors such as wiring harnesses and cables must be routed throughout the body from componentry. The vehicle body of a fully-assembled prior art vehicle is intertwined with the componentry and the connection devices, rendering separation of the body from its componentry difficult and labor-intensive, if not impossible. The use of long connectors increases the number of assembly steps required to attach a vehicle to its componentry. 
     Furthermore, prior art vehicles typically have internal combustion engines that have a height that is a significant proportion of the overall vehicle height. Prior art vehicle bodies are therefore designed with an engine compartment that occupies about a third of the front (or sometimes the rear) of the body length. Compatibility between an engine and a vehicle body requires that the engine fit within the body&#39;s engine compartment without physical part interference. Moreover, compatibility between a prior art chassis with an internal combustion engine and a vehicle body requires that the body have an engine compartment located such that physical part interference is avoided. For example, a vehicle body with an engine compartment in the rear is not compatible with a chassis with an engine in the front. 
     SUMMARY OF THE INVENTION 
     The invention is a self-contained chassis having substantially all of the mechanical, electrical, and structural componentry necessary for a fully functional vehicle, including at least an energy conversion system, a suspension and wheels, a steering system, and a braking system. The chassis has a simplified, and preferably standardized, interface with connection components to which bodies of substantially varying design can be attached. X-by-wire technology may be utilized to eliminate mechanical control linkages. Fuel cell technology may also be implemented in the energy conversion system. 
     The invention reduces the amount of time and resources required to design and manufacture new vehicle bodies. Body designs need only conform to the simple attachment interface of the chassis, eliminating the need to redesign or reconfigure expensive components. 
     The invention also allows a multitude of body configurations to share a common chassis, enabling economies of scale for major mechanical, electrical, and structural components. 
     Connection components, exposed and unobstructed, increase manufacturing efficiency because attachment of a body to the chassis requires only engagement of the connection components to respective complementary connection components on a vehicle body. 
     Vehicle owners can increase the functionality of their vehicles at a lower cost than possible with the prior art because a vehicle owner need buy only one chassis upon which to mount a multitude of body styles. 
    
    
     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. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic illustration in perspective view of a vehicle rolling platform according to an embodiment of the present invention; 
     FIG. 2 is a top view schematic illustration of the vehicle rolling platform shown in FIG. 1; 
     FIG. 3 is a bottom view schematic illustration of the vehicle rolling platform shown in FIGS. 1 and 2; 
     FIG. 4 is a schematic illustration in side view of a vehicle body pod and rolling platform attachment scenario according to the present invention that is useful with the embodiment of FIGS. 1-3; 
     FIG. 5 is a schematic illustration of a vehicle body pod and rolling platform attachment scenario, wherein body pods of differing configurations are each attachable to identical rolling platforms; 
     FIG. 6 is a schematic illustration of a steering system for use with the rolling platform and body pod shown in FIG. 4; 
     FIG. 7 is a schematic illustration of an alternative steering system for use in the rolling platform and body pod of FIG. 4; 
     FIG. 8 is a schematic illustration of a braking system for use with the rolling platform and body pod of FIG. 4; 
     FIG. 9 is a schematic illustration of an alternative braking system for use with the rolling platform and body pod of FIG. 4; 
     FIG. 10 is a schematic illustration of an energy conversion system for use with the rolling platform and body pod of FIG. 4; 
     FIG. 11 is a schematic illustration of an alternative energy conversion system for use with the rolling platform and body pod of FIG. 4; 
     FIG. 12 is a schematic illustration of a suspension system for use with the rolling platform of FIGS. 1-5; 
     FIG. 13 is a schematic illustration of an alternative suspension system for use with the rolling platform and body pod of FIG. 4; 
     FIG. 14 is a schematic illustration of a chassis computer and chassis sensors for use with the rolling platform and body pod of FIG. 4; 
     FIG. 15 is a schematic illustration of a master control unit with a suspension system, braking system, steering system, and energy conversion system for use with the rolling platform and body pod of FIG. 4; 
     FIG. 16 is a perspective illustration of a skinned rolling platform according to a further embodiment of the present invention; 
     FIG. 17 is a perspective illustration of a skinned rolling platform according to another embodiment of the present invention; 
     FIG. 18 is a side schematic illustration of a rolling platform with an energy conversion system including an internal combustion engine, and gasoline tanks; 
     FIG. 19 is a side schematic illustration of a rolling platform according to another embodiment of the invention, with a mechanical steering linkage and passenger seating attachment couplings; 
     FIGS. 20 and 20 a  show partial exploded perspective schematic illustrations of a rolling platform according to a further embodiment of the invention in an attachment scenario with a body pod, the rolling platform having multiple electrical connectors engageable with complementary electrical connectors in the body pod; and 
     FIG. 21 is a perspective schematic illustration of a skinned rolling platform according to yet another embodiment of the invention, the rolling platform having a movable control input device. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, a vehicle chassis  10  in accordance with the invention, also referred to as the “rolling platform,” includes a structural frame  11 . The structural frame  11  depicted in FIG. 1 comprises a series of interconnected structural elements including upper and lower side structural elements  12  and  14  that comprise a “sandwich”-like construction. Elements  12  and  14  are substantially rigid tubular (or optionally solid), members that extend longitudinally between the front and rear axle areas  16 ,  18 , and are positioned outboard relative to similar elements  20 ,  22 . The front and rear ends of elements  12 ,  14  are angled inboard, extending toward elements  20  and  22  and connecting therewith prior to entering the axle areas  16 ,  18 . For added strength and rigidity a number of vertical and angled structural elements extend between elements  12 ,  14 ,  20  and  22 . Similar to the elements  12 ,  14 ,  20  and  22 , which extend along the left side of the rolling platform  10 , a family of structural elements  26 ,  28 ,  30  and  32  extend along the right side thereof. 
     Lateral structural elements  34 ,  36  extend between elements  20 ,  30  and  22 ,  32 , respectively nearer the front axle area  16  and lateral structural elements  38 ,  40  extend between elements  20 ,  30  and  22 ,  32 , respectively nearer the rear axle area  18 , thereby defining a mid-chassis space  41 . The front axle area  16  is defined in and around structural elements  43 ,  44  at the rear and front, and on the sides by structural elements  46 ,  48  which may be extensions of the elements  20 ,  22 ,  30 ,  32  or connected therewith. Forward of the front axle area, a forward space is defined between element  44  and elements  50 ,  52 . The rear axle area  18  is defined in and around structural elements  53 ,  54  at the front and rear, and on the sides by structural elements  56 ,  58 , which may be extensions of the elements  20 ,  22 ,  30 ,  32  or connected therewith. Rearward of the rear axle area  18 , a rearward space is defined between element  54  and elements  60 ,  62 . Alternatively, the rear axle area  18  or the rearward space may be elevated relative to the rest of the structural frame  11  if necessary to accommodate an energy conversion system, and the frame may include other elements to surround and protect an energy conversion system. The frame defines a plurality of open spaces between the elements described above. Those skilled in the art will recognize materials and fastening methods suitable for use in the structural frame. For example, the structural elements may be tubular, aluminum, and welded at their respective connections to other structural elements. 
     The structural frame  11  provides a rigid structure to which an energy conversion system  67 , energy storage system  69 , suspension system  71  with wheels  73 ,  75 ,  77 ,  79  (each wheel having a tire  80 ), steering system  81 , and braking system  83  are mounted, as shown in FIGS. 1-3, and is configured to support an attached body  85 , as shown in FIG. 4. A person of ordinary skill in the art will recognize that the structural frame  11  can take many different forms, in addition to the cage-like structure of the embodiment depicted in FIGS. 1-3. For example, the structural frame  11  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 chassis components. 
     Referring to FIG. 2, a body attachment interface  87  is defined as the sum of all body connection components, i.e., connective elements that function to operably mate a vehicle body to the chassis  10 . The body connection components of the preferred embodiment include a plurality of load-bearing body-retention couplings  89  mounted with respect to the structural frame  11  and a single electrical connector  91 . 
     As shown in FIG. 4, the load-bearing body-retention couplings  89  are engageable with complementary attachment couplings  93  on a vehicle body  85  and function to physically fasten the vehicle body  85  to the chassis  10 . Those skilled in the art will recognize that a multitude of fastening and locking elements may be used and fall within the scope of the claimed invention. The load-bearing body-retention couplings  89  are preferably releasably engageable with complementary couplings, though non-releasably engageable couplings such as weld flanges or riveting surfaces may be employed within the scope of the claimed invention. Ancillary fastening elements may be used as lock downs in conjunction with the load-bearing body-retention couplings. Load-bearing surfaces without locking or fastening features on the chassis  10  may be used with the load-bearing body-retention couplings  89  to support the weight of an attached vehicle body  85 . In the preferred embodiment, the load-bearing body-retention couplings  89  include support brackets with bolt holes. Rubber mounts (not shown) located on the support brackets dampen vibrations transmitted between the body and the chassis. Alternatively, hard mounts may be employed for body-retention couplings. 
     The electrical connector  91  is engageable with a complementary electrical connector  95  on a vehicle body  85 . The electrical connector  91  of the preferred embodiment may perform multiple functions, or select combinations thereof. First, the electrical connector  91  may function as an electrical power connector, i.e., it may be configured to transfer electrical energy generated by components on the chassis  10  to a vehicle body  85  or other non-chassis destination. Second, the electrical connector  91  may function as a control signal receiver, i.e., a device configured to transfer non-mechanical control signals from a non-chassis source to controlled systems including the energy conversion system, steering system, and braking system. Third, the electrical connector  91  may function as a feedback signal conduit through which feedback signals are made available to a vehicle driver. Fourth, the electrical connector  91  may function as an external programming interface through which software containing algorithms and data may be transmitted for use by controlled systems. Fifth, the electrical connector may function as an information conduit through which sensor information and other information is made available to a vehicle driver. The electrical connector  91  may thus function as a communications and power “umbilical” port through which all communications between the chassis  10  and an attached vehicle body  85  are transmitted. 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. 
     If one electrical connector performing multiple functions is not desirable, for example, if a cumbersome wire bundle is required, or power transmission results in control signal interference, the body attachment interface  87  may include a plurality of electrical connectors  91  engageable with a plurality of complementary electrical connectors  95  on a vehicle body  85 , with different connectors performing different functions. A complementary electrical connector  95  performs functions complementary to the function of the electrical connector with which it engages, for example, functioning as a control signal transmitter when engaged with a control signal receiver. 
     Referring again to FIGS. 1-3, the energy conversion system  67 , energy storage system  69 , steering system  81 , and braking system  83 , are configured and positioned on the chassis  10  to minimize the overall vertical height of the chassis  10  and to maintain a substantially horizontal upper chassis face  96 . A face of an object is an imaginary surface that follows the contours of the object that face, and are directly exposed to, a particular direction. Thus, the upper chassis face  96  is an imaginary surface that follows the upwardly facing and exposed contours of the chassis frame  11  and systems mounted therein. Matable vehicle bodies have a corresponding lower body face  97  that is an imaginary surface that follows the downwardly facing and exposed contours of the body  85 , as shown in FIG.  4 . 
     Referring again to FIGS. 1-3, the structural frame  11  has a thickness defined as the vertical distance between its highest point (the top of structural element  20 ) and its lowest point (the bottom of structural element  22 ). In the preferred embodiment, the structural frame thickness is approximately 11 inches. To achieve a substantially horizontal upper chassis face  96 , the energy conversion system  67 , energy storage system  69 , steering system  81 , and braking system  83  are distributed throughout the open spaces and are configured, positioned, and mounted to the structural frame  11  such that the highest point of any of the energy conversion system  67 , energy storage system  69 , steering system  81 , and braking system  83  does not extend or protrude higher than the highest point of the structural frame  11  by an amount more than 50% of the structural frame thickness. Alternatively, the highest point of any of the energy conversion system  67 , energy storage system  69 , steering system  81 , and braking system  83  does not extend or protrude higher than the top of any of the tires  80 . Alternatively, the highest point of any of the energy conversion system  67 , energy storage system  69 , steering system  81 , and braking system  83  does not extend or protrude higher than the top of any of the wheels  73 ,  75 ,  77 ,  79 . In the context of the present invention, a tire is not considered part of a wheel. A wheel typically comprises a rim and a wheel disc or nave that connects the rim to a wheel hub, and does not include a mounted tire. A tire is mounted around the periphery of a wheel. The substantially horizontal upper chassis face  96  enables the attached vehicle body  85  to have a passenger area that extends the length of the chassis, unlike prior art bodies that have an engine compartment to accommodate a vertically-protruding internal combustion engine. 
     Most of the powertrain load is evenly distributed between the front and rear of the chassis so there is a lower center of gravity for the whole vehicle without sacrificing ground clearance, thereby enabling improved handling while resisting rollover forces. 
     Referring again to FIG. 4, the preferred embodiment of the rolling platform  10  is configured such that the lower body face  97  of a matable vehicle body  85  is positioned closely adjacent to the upper chassis face  96  for engagement with the rolling platform  10 . The body connection components have a predetermined spatial relationship relative to one another, and are sufficiently positioned, exposed, and unobstructed such that when a vehicle body  85  having complementary connection components (complementary attachment couplings  93  and a complementary electrical connector  95 ) in the same predetermined spatial relationship as the body connection components is sufficiently positioned relative to the upper chassis face  96  of a chassis  10  of the invention, the complementary connection components are adjacent to corresponding body connection components and ready for engagement, as depicted in FIG.  4 . In the context of the present invention, a body connection component having a protective covering is exposed and unobstructed if the protective covering is removable or retractable. 
     Each body connection component has a spatial relationship relative to each of the other body connection components that can be expressed, for example, as a vector quantity. Body connection components and complementary connection components have the same predetermined spatial relationship if the vector quantities that describe the spatial relationship between a body connection component and the other body connection components to be engaged also describe the spatial relationship between a corresponding complementary connection component and the other complementary connection components to be engaged. For example, the spatial relationship may be defined as follows: a first body connection component is spaced a distance Ax+By from a reference point; a second body connection component is spaced a distance Cx+Dy from the reference point; a third body connection component is spaced a distance Ex+Fy from the reference point, etc. Corresponding complementary connection components in the same predetermined spatial relationship are spaced in a mirror image relationship in the lower body face, as depicted in FIGS. 4 and 5. A protective covering (not shown) may be employed to protect any of the body connection components. 
     The body connection components and the complementary connection components are preferably adjacent without positional modification when a vehicle body  85  is sufficiently positioned relative to a chassis  10  of the invention; however, in the context of the present invention, the body connection components may be movable relative to each other within a predetermined spatial relationship to accommodate build tolerances or other assembly issues. For example, an electrical connector may be positioned and operably connected to a signal-carrying cable. The cable may be fixed relative to the structural frame at a point six inches from the electrical connector. The electrical connector will thus be movable within six inches of the fixed point on the cable. A body connection component is considered adjacent to a complementary connection component if one or both are movable within a predetermined spatial relationship so as to be in contact with each other. 
     Referring to FIG. 5, the body-attachment interface of the claimed invention enables compatibility between the chassis  10  and different types of bodies  85 ,  85 ′,  85 ″ having substantially different designs. Bodies  85 ,  85 ′,  85 ″ having a common base  98  with complementary attachment couplings  93  and complementary electrical connectors  95  in the same predetermined spatial relationship with one another as the predetermined spatial relationship between body connection components on the body-attachment interface  87 , are each matable with the chassis  10  by positioning the body  85 ,  85 ′,  85 ″ relative to the chassis  10  such that each complementary attachment coupling  93  is adjacent to a load-bearing body-retention coupling  89 , and the complementary electrical connector  95  is adjacent to the electrical connector  91 . In accordance with the preferred embodiment of the present invention, all bodies and chassis comply with this common, standardized interface system, thereby enabling a wide array of different body types and styles to be attached to a single chassis design. The substantially horizontal upper chassis face  96  also facilitates compatibility between the rolling platform  10  and a multitude of differently-configured body styles. The common base  98  functions as a body structural unit and forms the lower body face  97  in the preferred embodiment. FIG. 5 schematically depicts a sedan  85 , a van  85 ′, and a pickup truck  85 ″ each having a common base  98 . 
     The body connection components are preferably sufficiently exposed at a chassis face to facilitate attachment to complementary connection components on a matable vehicle body. Similarly, complementary-connection components on a matable vehicle body are sufficiently exposed at a body face to facilitate attachment to body connection components on a vehicle chassis. In the preferred embodiment of the invention, the body connection components are located at or above the upper chassis face for engagement with complementary connection components located at or below a lower body face. 
     It is within the scope of the claimed invention to employ a connection device to engage or operably connect a body connection component with a distant complementary connection component, in the situation where a vehicle body does not have complementary connection components in the same predetermined spatial relationship as the body connection components on a vehicle chassis. For example, a cable having two connectors, one connector engageable with the electrical connector on a body attachment interface and the other connector engageable with a complementary connector on a matable vehicle body, may be used to operably connect the electrical connector and the complementary connector. 
     The bodies  85 ,  85 ′,  85 ″ shown schematically in FIG. 5 each use all of the body connection components on the vehicle chassis  10 . However, within the scope of the claimed invention, a chassis may have more body connection components than are actually mated with a vehicle body. For example, a chassis may have ten load-bearing body-retention couplings, and be matable with a body that engages only five of the ten load-bearing body-retention couplings. Such an arrangement is particularly useful when an attachable body is of a different size than the chassis. For example, a matable body may be smaller than a chassis. Similarly, and within the scope of the claimed invention, a body may be modular such that separate body components are independently connected to the vehicle chassis by the load-bearing body-retention couplings. 
     A body may have more complementary connection components than are engageable with the body connection components of a particular chassis. Such an arrangement may be employed to enable a particular body to be matable to multiple chassis each having a different predetermined spatial relationship among its body connection components. 
     The load-bearing body-retention couplings  89  and the electrical connector  91  are preferably releasably engageable without damage to either an attached body  85  or the chassis  10 , thereby enabling removal of one body  85  from the chassis  10  and installation of a different body  85 ′,  85 ″ on the chassis  10 . 
     In the preferred embodiment, the body-attachment interface  87  is characterized by the absence of any mechanical control signal-transmission linkages and any couplings for attaching mechanical control signal-transmission linkages. Mechanical control linkages, such as steering columns, limit the compatibility between a chassis and bodies of different configurations. 
     Referring to FIG. 1, the steering system  81  is housed in the front axle area  16  and is operably connected to the front wheels  73 ,  75 . Preferably, the steering system  81  is responsive to non-mechanical control signals. In the preferred embodiment, the steering system  81  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 on the body attachment interface  87 , and respond in conformity to the electronic control signals. 
     Referring to FIG. 6, the by-wire steering system  81  of the preferred embodiment includes a steering control unit  98 , and a steering actuator  99 . Sensors  100  are located on the chassis  10  and transmit sensor signals  101  carrying information concerning the state or condition of the chassis  10  and its component systems. The sensors  100  may include position sensors, velocity sensors, acceleration sensors, pressure sensors, force and torque sensors, flow meters, temperature sensors, etc. The steering control unit  98  receives and processes sensor signals  101  from the sensors  100  and electrical steering control signals  102  from the electrical connector  91 , and generates steering actuator control signals  103  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  101  may include yaw rate, lateral acceleration, angular wheel velocity, tie-rod force, steering angle, chassis velocity, etc. 
     The steering actuator  99  is operably connected to the front wheels  73 ,  75  and configured to adjust the steering angle of the front wheels  73 ,  75  in response to the steering actuator control signals  103 . Actuators in a by-wire system transform electronic control signals into a mechanical action or otherwise influence a system&#39;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  99  is an electric drive motor configured to adjust a mechanical steering rack. 
     Referring again to FIG. 6, the preferred embodiment of the chassis  10  is configured such that it is steerable by any source of compatible electrical steering control signals  102  connected to the electrical connector  91 . FIG. 6 depicts a steering transducer  104  located on an attached vehicle body  85  and connected to a complementary electrical connector  95 . 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, depressing a pedal, pressing a button, or the like. Transducers utilize sensors, typically position and force sensors, to convert the mechanical input to an electrical signal. In the preferred embodiment, a +/−20 degree slide mechanism is used for driver input, and an optical encoder is used to read input rotation. 
     The complementary electrical connector  95  is coupled with the electrical connector  91  of the body attachment interface  87 . The steering transducer  104  converts vehicle driver-initiated mechanical steering control signals  105  to electrical steering control signals  102  which are transmitted via the electrical connector  91  to the steering control unit  98 . In the preferred embodiment, the steering control unit  98  generates steering feedback signals  106  for use by a vehicle driver and transmits the steering feedback signals  106  through the electrical connector  91 . Some of the sensors  100  monitor linear distance movement of the steering rack and vehicle speed. This information is processed by the steering control unit  98  according to a stored algorithm to generate the steering feedback signals  106 . A torque control motor operably connected to the slide mechanism receives the steering feedback signals  106  and is driven in the opposite direction of the driver&#39;s mechanical input. 
     In the context of the present invention, a “by-wire” system may be an actuator connected directly to an electrical connector in the body attachment interface. An alternative by-wire steering system  81 ′ within the scope of the claimed invention is depicted schematically in FIG. 7, wherein like reference numbers refer to like components from FIG. 6. A steering actuator  99  configured to adjust the steering angle of the front wheels  73 ,  75  is connected directly to the electrical connector  91 . In this embodiment, a steering control unit  98 ′ and a steering transducer  104  may be located in an attached vehicle body  85 . The steering transducer  104  would transmit electrical steering control signals  102  to the steering control unit  98 ′, and the steering control unit  98 ′ would transmit steering actuator control signals  103  to the steering actuator  99  via the electrical connector  91 . Sensors  100  positioned on the chassis  10  transmit sensor signals  101  to the steering control unit  98 ′ via the electrical connector  91  and the complementary electrical connector  95 . 
     Examples of steer-by-wire systems are described in U.S. Pat. No. 6,176,341, issued Jan. 23, 2001 to Delphi Technologies, Inc; U.S. Pat. No. 6,208,923, issued Mar. 27, 2001 to Robert Bosch GmbH; U.S. Pat. No. 6,219,604, issued Apr. 17, 2001 to Robert Bosch GmbH; U.S. Pat. No. 6,318,494, issued Nov. 20, 2001 to Delphi Technologies, Inc.; U.S. Pat. No. 6,370,460, issued Apr. 9, 2002 to Delphi Technologies, Inc.; and U.S. Pat. No. 6,394,218, issued May 28, 2002 to TRW Fahrwerksysteme GmbH &amp; Co. KG; which are hereby incorporated by reference in their entireties. 
     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. 
     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. 
     The steering control unit of the &#39;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. 
     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. 
     Referring again to FIG. 1, a braking system  83  is mounted to the structural frame  11  and is operably connected to the wheels  73 ,  75 ,  77 ,  79 . The braking system is configured to be responsive to non-mechanical control signals. In the preferred embodiment, the braking system  83  is by-wire, as depicted schematically in FIG. 8, wherein like reference numbers refer to like components from FIGS. 6 and 7. Sensors  100  transmit sensor signals  101  carrying information concerning the state or condition of the chassis  10  and its component systems to a braking control unit  107 . The braking control unit  107  is connected to the electrical connector  91  and is configured to receive electrical braking control signals  108  via the electrical connector  91 . The braking control unit  107  processes the sensor signals  101  and the electrical braking control signals  108  and generates braking actuator control signals  109  according to a stored algorithm. The braking control unit  107  then transmits the braking actuator control signals  109  to braking actuators  110 ,  111 ,  112 ,  113  which act to reduce the angular velocity of the wheels  73 ,  75 ,  77 ,  79 . Those skilled in the art will recognize the manner in which the braking actuators  110 ,  111 ,  112 ,  113  act on the wheels  73 ,  75 ,  77 ,  79 . 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. 
     The braking control unit  107  may also generate braking feedback signals  114  for use by a vehicle driver and transmit the braking feedback signals  114  through the electrical connector  91 . In the preferred embodiment, the braking actuators  110 ,  111 ,  112 ,  113  apply force through a caliper to a rotor at each wheel. Some of the sensors  100  measure the applied force on each caliper. The braking control unit  107  uses this information to ensure synchronous force application to each rotor. 
     Referring again to FIG. 8, the preferred embodiment of the chassis  10  is configured such that the braking system is responsive to any source of compatible electrical braking control signals  108 . A braking transducer  115  may be located on an attached vehicle body  85  and connected to a complementary electrical connector  95  coupled with the electrical connector  91 . The braking transducer  115  converts vehicle driver-initiated mechanical braking control signals  116  into electrical form and transmits the electrical braking control signals  106  to the braking control unit via the electrical connector  91 . In the preferred embodiment, the braking transducer  115  includes two hand-grip type assemblies. The braking transducer  115  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  116  to electrical braking control signals  108 . The braking control unit  107  processes both the rate and amount of applied pressure to provide both normal and panic stopping. 
     An alternative brake-by-wire system  83 ′ within the scope of the claimed invention is depicted in FIG. 9, wherein like reference numbers refer to like components from FIGS. 6-8. The braking actuators  110 ,  111 ,  112 ,  113  and sensors  100  are connected directly to the electrical connector  91 . In this embodiment, a braking control unit  107 ′ may be located in an attached vehicle body  85 . A braking transducer  115  transmits electrical braking control signals  108  to the braking control unit  107 ′, and the braking control unit  107 ′ transmits braking actuator signals  109  to the braking actuators  110 ,  111 ,  112 ,  113  via the electrical connector  91 . 
     Examples of brake-by-wire systems are described in U.S. Pat. No. 5,366,281, issued Nov. 22, 2994 to General Motors Corporation; U.S. Pat. No. 5,823,636, issued Oct. 20, 1998 to General Motors Corporation; U.S. Pat. No. 6,305,758, issued Oct. 23, 2001 to Delphi Technologies, Inc.; and U.S. Pat. No. 6,390,565, issued May 21, 2002 to Delphi Technologies, Inc.; which are hereby incorporated by reference in their entireties. 
     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. 
     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. 
     Referring again to FIG. 1, the energy storage system  69  stores energy that is used to propel the chassis  10 . For most applications, the stored energy will be in chemical form. Examples of energy storage systems  69  include fuel tanks and electric batteries. In the embodiment shown in FIG. 1, the energy storage system  69  includes two compressed gas cylinder storage tanks  121  (5,000 psi, or 350 bars) mounted within the mid-chassis space  41  and configured to store compressed hydrogen gas. Employing more than two compressed gas cylinder storage tanks may be desirable to provide greater hydrogen storage capacity. Instead of compressed gas cylinder storage tanks  121 , an alternate form of hydrogen storage may be employed such as metal or chemical hydrides. Hydrogen generation or reforming may also be used. 
     The energy conversion system  67  converts the energy stored by the energy storage system  69  to mechanical energy that propels the chassis  10 . In the preferred embodiment, depicted in FIG. 1, the energy conversion system  67  includes a fuel cell stack  125  located in the rear axle area  18 , and an electric traction motor  127  located in the front axle area  16 . The fuel cell stack  125  produces a continuously available power of 94 kilowatts. Fuel cell systems for vehicular use are described in U.S. Pat. No. 6,195,999, issued Mar. 6, 2001 to General Motors Corporation; U.S. Pat. No. 6,223,843, issued May 1, 2001 to General Motors Corporation; U.S. Pat. No. 6,321,145, issued Nov. 20, 2001 to Delphi Technologies, Inc.; and U.S. Pat. No. 6,394,207, issued May 28, 2002 to General Motors Corporation; which are hereby incorporated by reference in their entireties. 
     The fuel cell stack  125  is operably connected to the compressed gas cylinder storage tanks  121  and to the traction motor  127 . The fuel cell stack  125  converts chemical energy in the form of hydrogen from the compressed gas cylinder storage tanks  121  into electrical energy, and the traction motor  127  converts the electrical energy to mechanical energy, and applies the mechanical energy to rotate the front wheels  73 ,  75 . Optionally, the fuel cell stack  125  and traction motor  127  are switched between the front axle area  16  and rear axle area  18 . Optionally, the energy conversion system includes an electric battery (not shown) in hybrid combination with the fuel cell to improve chassis acceleration. Other areas provided between the structural elements are useful for housing other mechanisms and systems for providing the functions typical of an automobile as shown in FIGS. 2 and 3. Those skilled in the art will recognize other energy conversion systems  67  that may be employed within the scope of the present invention. 
     The energy conversion system  67  is configured to respond to non-mechanical control signals. The energy conversion system  67  of the preferred embodiment is controllable by-wire, as depicted in FIG.  10 . An energy conversion system control unit  128  is connected to the electrical connector  91  from which it receives electrical energy conversion system control signals  129 , and sensors  100  from which it receives sensor signals  101  carrying information about various chassis conditions. In the preferred embodiment, the information conveyed by the sensor signals  101  to the energy conversion system control unit  128  includes chassis velocity, electrical current applied, rate of acceleration of the chassis, and motor shaft speed to ensure smooth launches and controlled acceleration. The energy conversion system control unit  128  is connected to an energy conversion system actuator  130 , and transmits energy conversion system actuator control signals  131  to the energy conversion system actuator  130  in response to the electrical energy conversion system control signals  129  and sensor signals  101  according to a stored algorithm. The energy conversion system actuator  130  acts on the fuel cell stack  125  or traction motor  127  to adjust energy output. Those skilled in the art will recognize the various methods by which the energy conversion system actuator  130  may adjust the energy output of the energy conversion system. For example, a solenoid may alternately open and close a valve that regulates hydrogen flow to the fuel cell stack. Similarly, a compressor that supplies oxygen (from air) to the fuel cell stack may function as an actuator, varying the amount of oxygen supplied to the fuel cell stack in response to signals from the energy conversion system control unit. 
     An energy conversion system transducer  132  may be located on a vehicle body  85  and connected to a complementary electrical connector  95  engaged with the electrical connector  91 . The energy conversion system transducer  132  is configured to convert mechanical energy conversion system control signals  133  to electrical energy conversion system control signals  129 . 
     In another embodiment of the invention, as shown schematically in FIG. 11, wherein like reference numbers refer to like components from FIGS. 6-10, wheel motors  135 , also known as wheel hub motors, are positioned at each of the four wheels  73 ,  75 ,  77 ,  79 . Optionally, wheel motors  135  may be provided at only the front wheels  73 ,  75  or only the rear wheels  77 ,  79 . The use of wheel motors  135  reduces the height of the chassis  10  compared to the use of traction motors, and therefore may be desirable for certain uses. 
     Referring again to FIG. 2, a conventional heat exchanger  137  and electric fan system  139 , operably connected to the fuel cell stack  125  to circulate coolant for waste heat rejection, is carried in an opening that exists between the rear axle area  18  and the structural elements  54 ,  60 . The heat exchanger  137  is set at an inclined angle to reduce its vertical profile, but to provide adequate heat rejection it also extends slightly above the top of elements  12 ,  26  (as seen in FIG.  4 ). Although the fuel cell stack  125 , heat exchanger  137  and electric fan system  139  extend above the structural elements, their protrusion into the body pod space is relatively minor when compared to the engine compartment requirements of a conventionally designed automobile, especially when the chassis height of the preferred embodiment is approximately a mere 15 inches (28 centimeters). Optionally, the heat exchanger  137  is packaged completely within the chassis&#39; structure with airflow routed through channels (not shown). 
     Referring again to FIG. 1, the suspension system  71  is mounted to the structural frame  11  and is connected to four wheels  73 ,  75 ,  77 ,  79 . Those skilled in the art will understand the operation of a suspension system, and recognize that a multitude of suspension system types may be used within the scope of the claimed invention. The suspension system  71  of the preferred embodiment of the invention is electronically controlled, as depicted schematically in FIG.  12 . 
     Referring to FIG. 12, the behavior of the electronically controlled suspension system  71  in response to any given road input is determined by a suspension control unit  141 . Sensors  100  located on the chassis  10  monitor various conditions such as vehicle speed, angular wheel velocity, and wheel position relative to the chassis  10 . The sensors  100  transmit the sensor signals  101  to the suspension control unit  141 . The suspension control unit  141  processes the sensor signals  101  and generates suspension actuator control signals  142  according to a stored algorithm. The suspension control unit  141  transmits the suspension actuator control signals  142  to four suspension actuators  143 ,  144 ,  145 ,  146 . Each suspension actuator  143 ,  144 ,  145 ,  146  is operably connected to a wheel  73 ,  75 ,  77 ,  79  and determines, in whole or in part, the position of the wheel  73 ,  75 ,  77 ,  79  relative to the chassis  10 . The suspension actuators of the preferred embodiment are variable-force, real time, controllable dampers. The suspension system  71  of the preferred embodiment is also configured such that chassis ride height is adjustable. Separate actuators may be used to vary the chassis ride height. 
     In the preferred embodiment, the suspension control unit  141  is programmable and connected to the electrical connector  91  of the body-attachment interface  87 . A vehicle user is thus able to alter suspension system  71  characteristics by reprogramming the suspension control unit  141  with suspension system software  147  via the electrical connector  91 . 
     In the context of the claimed invention, electronically-controlled suspension systems include suspension systems without a suspension control unit located on the chassis  10 . Referring to FIG. 13, wherein like reference numbers are used to reference like components from FIG. 12, suspension actuators  143 ,  144 ,  145 ,  146  and suspension sensors  100  are connected directly to the electrical connector  91 . In such an embodiment, a suspension control unit  141 ′ located on an attached vehicle body  85  can process sensor signals  101  transmitted through the electrical connector  91 , and transmit suspension actuator control signals  142  to the suspension actuators  143 ,  144 ,  145 ,  146  via the electrical connector  91 . 
     Examples of electronically controlled suspension systems are described in U.S. Pat. No. 5,606,503, issued Feb. 25, 1997 to General Motors Corporation; U.S. Pat. No. 5,609,353, issued Mar. 11, 1997 to Ford Motor Company; and U.S. Pat. No. 6,397,134, issued May 28, 2002 to Delphi Technologies, Inc.; which are hereby incorporated by reference in their entireties. 
     U.S. Pat. No. 6,397,134 describes an electronically controlled suspension system that provides improved suspension control through steering crossover events. In particular, the system senses a vehicle lateral acceleration and a vehicle steering angle and stores, for each direction of sensed vehicle lateral acceleration, first and second sets of enhanced suspension actuator control signals for the suspension actuators of the vehicle. Responsive to the sensed vehicle lateral acceleration and sensed vehicle steering angle, the system applies the first set of enhanced actuator control signals to the suspension actuators if the sensed steering angle is in the same direction as the sensed lateral acceleration and alternatively applies the second set of enhanced actuator control signals to the suspension actuators if the sensed steering angle is in the opposite direction as the sensed lateral acceleration. 
     U.S. Pat. No. 5,606,503 describes a suspension control system for use in a vehicle including a suspended vehicle body, four un-suspended vehicle wheels, four variable force actuators mounted between the vehicle body and wheels, one of the variable force actuators at each corner of the vehicle, and a set of sensors providing sensor signals indicative of motion of the vehicle body, motion of the vehicle wheels, a vehicle speed and an ambient temperature. The suspension control system comprises a microcomputer control unit including: means for receiving the sensor signals; means, responsive to the sensor signals, for determining an actuator demand force for each actuator; means, responsive to the vehicle speed, for determining a first signal indicative of a first command maximum; means, responsive to the ambient temperature, for determining a second signal indicative of a second command maximum; and means for constraining the actuator demand force so that it is no greater than a lesser of the first and second command maximums. 
     Electrically conductive wires (not shown) are used in the preferred embodiment to transfer signals between the chassis  10  and an attached body  85 , and between transducers, control units, and actuators. Those skilled in the art will recognize that other non-mechanical means of sending and receiving signals between a body and a chassis, and between transducers, control units, and actuators may be employed and fall within the scope of the claimed invention. Other non-mechanical means of sending and receiving signals include radio waves and fiber optics. 
     The by-wire systems are networked in the preferred embodiment, in part to reduce the quantity of dedicated wires connected to the electrical connector  91 . A serial communication network is described in U.S. Pat. No. 5,534,848, issued Jul. 9, 1996 to General Motors Corporation, which is hereby incorporated by reference in its entirety. An example of a networked drive-by-wire system is described in U.S. Patent Application Publication No. U.S. 2001/0029408, Ser. No. 09/775,143, which is hereby incorporated by reference in its entirety. Those skilled in the art will recognize various networking devices and protocols that may be used within the scope of the claimed invention, such as SAE J1850 and CAN (“Controller Area Network”). A TTP (“Time Triggered Protocol”) network is employed in the preferred embodiment of the invention for communications management. 
     Some of the information collected by the sensors  100 , such as chassis velocity, fuel level, and system temperature and pressure, is useful to a vehicle driver for operating the chassis and detecting system malfunctions. As shown in FIG. 14, the sensors  100  are connected to the electrical connector  91  through a chassis computer  153 . Sensor signals  101  carrying information are transmitted from the sensors  100  to the chassis computer  153 , which processes the sensor signals  101  according to a stored algorithm. The chassis computer  153  transmits the sensor signals  101  to the electrical connector  91  when, according to the stored algorithm, the sensor information is useful to the vehicle driver. For example, a sensor signal  101  carrying temperature information is transmitted to the electrical connector  91  by the chassis computer  153  when the operating temperature of the chassis  10  is unacceptably high. A driver-readable information interface  155  may be attached to a complementary electrical connector  95  coupled with the electrical connector  91  and display the information contained in the sensor signals  101 . Driver-readable information interfaces include, but are not limited to, gauges, meters, LED displays, and LCD displays. The chassis may also contain communications systems, such as antennas and telematics systems, that are operably connected to an electrical connector in the body-attachment interface and configured to transmit information to an attached vehicle body. 
     One control unit may serve multiple functions. For example, as shown in FIG. 15, a master control unit  159  functions as the steering control unit, braking control unit, suspension control unit, and energy conversion system control unit. 
     Referring again to FIG. 15, the energy conversion system  67  is configured to transmit electrical energy  160  to the electrical connector  91  to provide electric power for systems located on an attached vehicle body, such as power windows, power locks, entertainment systems, heating, ventilating, and air conditioning systems, etc. Optionally, if the energy storage system  69  includes a battery, then the battery may be connected to the electrical connector  91 . In the preferred embodiment, the energy conversion system  67  includes a fuel cell stack that generates electrical energy and is connected to the electrical connector  91 . 
     FIG. 16 shows a chassis  10  with rigid covering, or “skin,”  161  and an electrical connector or coupling  91  that functions as an umbilical port. The rigid covering  161  may be configured to function as a vehicle floor, which is useful if an attached vehicle body  85  does not have a lower surface. In FIG. 17 a similarly equipped chassis  10  is shown with an optional vertical fuel cell stack  125 . The vertical fuel cell stack  125  protrudes significantly into the body pod space which is acceptable for some applications. The chassis  10  also includes a manual parking brake interface  162  that may be necessary for certain applications and therefore is also optionally used with other embodiments. 
     FIG. 18 depicts an embodiment of the invention that may be advantageous in some circumstances. The energy conversion system  67  includes an internal combustion engine  167  with horizontally-opposed cylinders, and a transmission  169 . The energy storage system  69  includes a gasoline tank  171 . 
     FIG. 19 depicts an embodiment of the invention wherein the steering system  81  has mechanical control linkages including a steering column  173 . Passenger seating attachment couplings  175  are present on the body attachment interface  87 , allowing the attachment of passenger seating assemblies to the chassis  10 . 
     FIGS. 20 and 20 a  depict a chassis  10  within the scope of the invention and a body  85  each having multiple electrical connectors  91  and multiple complementary electrical connectors  95 , respectively. For example, a first electrical connector  91  may be operably connected to the steering system and function as a control signal receiver. A second electrical connector  91  may be operably connected to the braking system and function as a control signal receiver. A third electrical connector  91  may be operably connected to the energy conversion system and function as a control signal receiver. A fourth electrical connector  91  may be operably connected to the energy conversion system and function as an electrical power connector. Four multiple wire in-line connectors and complementary connectors are used in the embodiment shown in FIGS. 20 and 20 a . FIG. 20 a  depicts an assembly process for attaching corresponding connectors  91 ,  95 . 
     Referring to FIG. 21, a further embodiment of the claimed invention is depicted. The chassis  10  has a rigid covering  161  and a plurality of passenger seating attachment couplings  175 . A driver-operable control input device  177  containing a steering transducer, a braking transducer, and an energy conversion system transducer, is operably connected to the steering system, braking system, and energy conversion system by wires  179  and movable to different attachment points. 
     The embodiment depicted in FIG. 21 enables bodies of varying designs and configurations to mate with a common chassis design. A vehicle body without a lower surface but having complementary attachment couplings is matable to the chassis  10  at the load-bearing body retention couplings  89 . Passenger seating assemblies may be attached at passenger seating attachment couplings  175 . 
     As set forth in the claims, various features shown and described in accordance with the different embodiments of the invention illustrated may be combined. 
     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.