Patent Publication Number: US-2022212536-A1

Title: Adjustable throttle pedal assembly

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates to a throttle pedal (also known as an accelerator or gas pedal), and in particular but not exclusively, the invention relates to an adjustable throttle pedal assembly for automobiles. 
     BACKGROUND TO THE INVENTION 
     Throttle pedal assemblies with a non-uniform response are known. 
     The most common example of a throttle pedal assembly with a non-uniform response force is the “kick-down” response, familiar in many vehicles with automatic transmissions (referred to as “automatic vehicles”). These systems use a force indent (with a greater response force) after the 100% throttle position, which, when pressed causes a down-shift to allow greater acceleration. This is perceived by the driver as a foot-operated non-latching switch and is frequently provided by a separate switch (comprising a spring to increase the response force), which is pressed by the underside of the throttle pedal. 
     Another modification to provide an increased force under certain conditions has been proposed in an earlier patent application by the present applicant—WO2017/220981 proposes a “Virtual Footrest” apparatus, in which a deployable element comprising a sprung casing which is deployable to a position beneath the throttle pedal, to support the pedal such that it acts as a footrest in cruise control mode. The spring allows the throttle pedal to be depressed even when the element is deployed, but increases the response force, so that it can act as a footrest. 
     Bosch® have also proposed an “active pedal”, which provides a haptic signal in the form of a gentle vibration, to alert a driver of a vehicle with a hybrid transmission when the combustion engine is about to take over from the electric motor, so they can reduce pressure on the throttle pedal and remain in the electric mode. 
     The present invention seeks to provide an improved throttle pedal assembly. 
     SUMMARY OF THE INVENTION 
     According to a first aspect of the invention there is provided an adjustable throttle pedal assembly, the adjustable throttle pedal assembly comprising a depressible throttle pedal, biased away from the depressed position, towards a rest position, and an electromagnetic brake, operable to adjust the force required to depress the throttle pedal. 
     The provision of an electromagnetic brake can add a retarding force to the throttle pedal, increasing the force required to depress the throttle pedal. The retarding force can be very versatile in terms of the haptic feedback and force/travel relationship created, and instantaneous in its response. This can be useful in providing a number of functions as discussed above, and more. Importantly, whilst the electromagnetic brake could provide one of the functions discussed, it could also serve multiple functions, thus reducing parts-count/inventory. 
     In particular, the electromagnetic brake may provide an increased force so as to act as a “virtual footrest” as discussed above. 
     Alternatively/additionally, for use in an automatic vehicle, the electromagnetic brake may provide an increased force so as to act as a “virtual kick-down switch”, i.e. providing a perceivable increase of force at a particular point, at which point the automatic transmission will down-shift. 
     Alternatively/additionally, for use in a hybrid vehicle, the electromagnetic brake may provide an “ICE force-indent”, i.e. an increased force at the point which the vehicle will need to start the internal combustion engine (ICE), or a predetermined pedal-travel distance before the vehicle will need to start the internal combustion engine. 
     Alternatively/additionally, the electromagnetic brake may be adjustable to provide different customisable “pedal-weight” settings, to suit a driver&#39;s preferred force feedback, i.e. harder/easier to depress overall (regardless of whether it is harder to depress at certain points (e.g. kick-down, engaging ICE and/or in “virtual footrest” mode)). 
     The adjustability to provide customisable “pedal weight” settings, may be between discrete pedal weight settings, e.g. light, medium and firm, with a greater retarding force provided by the electromagnetic brake in to provide a firmer (“heavier”) weight, or could be calibrated to a given driver. For example, drivers with smaller feet/legs may prefer a lighter weight (i.e. less force required to depress the pedal) and those with larger feet/legs may prefer a heavier weight (greater force required to depress the pedal). 
     The electromagnetic brake may comprise a rotatable friction plate coupled to the throttle pedal and a static electromagnet coupled to a mount, whereby increasing the voltage applied to the electromagnet increases the attraction between the friction plate and the mount, and hence increases the force required to depress the throttle pedal. Or, vice versa, the friction plate may be coupled to the mount and the electromagnet may be coupled to the throttle pedal, with increased voltage increasing the attraction between the friction plate and the throttle pedal, and hence increasing the force required to depress the throttle pedal. The friction plate may be formed from a material which is magnetic but does not retain magnetism after being in contact with a magnet, for example pure iron. 
     One portion of the electromagnetic brake, for example, the friction plate, may be mounted so as to be rotatable in one direction, such that the electromagnetic brake does not affect the force of the bias away from the depressed position. The mounting may be by means of a one-way coupling, such as a “sprag clutch”, to which the friction plate may be attached. This feature is useful from a safety point of view, as it means that whilst the force required to depress the throttle can be increased as desired, the ordinary biasing force (for example of a spring) that moves the throttle pedal back to the (undepressed) rest position will always be sufficient, regardless of the state of the electromagnetic brake, preventing/restricting unintended vehicle acceleration and ensuring that when the pedal is released, the vehicle will behave in the normal fashion (i.e. normally decelerating), so that despite the addition of the functions of the electromagnetic clutch, there will be a level of familiarity and reassurance to the manner of its function. 
     The rotatable friction plate may be separated from the static electromagnet by an air gap. This can avoid the electromagnetic brake affecting the force required to depress the pedal when it is de-energised. 
     The electromagnetic brake may be selected such that it has a maximum retarding force (i.e. the force against depression of the pedal) of less than a predetermined safety threshold. The safety threshold may, for example, be no more than 5 times, no more than 3 times, or no more than twice the normal biasing force of the pedal when the brake is inactive. The provision of a safety threshold can help avoid the force required to depress the pedal being too high—e.g. so high that the pedal is in effect locked, with the driver unable to press it, or for example unable to press through a “force indent” provided by the “virtual kick-down switch”, “virtual footrest” and/or “ICE force indent”. 
     The throttle pedal assembly may comprise a pedal-travel sensor. The pedal travel sensor may be insensitive to electromagnetic interference—for example, it could be an optical sensor, or, it could be sufficiently remote from the electromagnet of the electromagnetic brake that the electromagnet does not cause inaccurate measurement. 
     The throttle pedal assembly may comprise a controller. The controller may be mounted to the mount, or may be a module of one of another on-board computer, many of which are found in modern vehicles. 
     The controller may be operable to output signals to the electromagnetic brake. The output signals may be an output voltage selected so as to adjust the force required to depress the pedal. 
     The controller may be operable to receive input signals and to select the output voltage in dependence on the input signals. 
     The input signals may comprise inputs from the pedal-travel sensor. These inputs can determine the point of travel of the pedal, which can be used to determine the necessary feedback to provide the appropriate “force indents” discussed above 
     The input signals may be provided by user-selectable inputs, for example a HMI, such as a simple button or a touch-screen and may be an indication of desired pedal weight, whereby a higher output voltage will be provided for a heavier pedal weight signal. 
     Alternatively/additionally, the controller may be capable of running a calibration setting, saving the result to memory and using the memorised result as an input, upon which the output voltage depends. 
     For example, to calibrate the pedal, in response to a signal (e.g. from an HMI) to enter a calibration sequence, the controller may apply maximum resistive force (i.e. maximum effective voltage) to the electromagnetic brake (and optionally may instruct the driver to rest his/her foot on the pedal and optionally instruct the driver to relax the leg as if using a foot rest); the controller may then gradually reduce the resistive force, and monitor the pedal travel sensor, until the pedal begins to move, so as to determine the minimum amount of force required to balance the foot-force and prevent movement; the controller may use this minimum amount of force to select a customised pedal-weight setting, i.e. the optimum force to apply against depression of the pedal. 
     The output voltage may be based on customised pedal weight setting and variable depending on other inputs (e.g. data relevant to operation of the “virtual kick-down switch”, “virtual footrest” and/or “ICE force indent”, such that the force can be increased as necessary to provide those (or any other) haptic responses). 
     The minimum amount of force may be saved as a personal setting, optionally with other settings, such as seat settings, optionally selected in a similar manner, for example by pressing a memory button on the seat to select the correct calibration for the specific driver, or alternatively coded to a particular key. 
     In an alternative, the pedal weight could be set in dependence on seat position (the controller receiving a signal indicative of the position of the seat)—seat position is generally correlated with the driver&#39;s height, which typically correlates with their weight and size of foot, so this could be used as a rough gauge of ideal resistive force requirements (with a seat position indicative of a smaller driver resulting in a lower resistive force, i.e. a “lighter” pedal). Of course, this is likely to be less accurate than a calibration, and possibly less to a driver&#39;s personal taste than a selectable setting. However, it avoids the need to go through a “setup”, which can be undesirable, whilst still providing a weight that is more likely to suit the driver than the “one size fits all” approach that is typical in the car-industry today, with a fixed force/travel relationship for all vehicles in a model range, which is based largely on the force of the bias (e.g. a biasing spring) and not customisable at all. 
     Where the adjustable throttle pedal assembly is operable to provide an increased force so as to act as a “virtual footrest”, the controller may be operable, upon receiving an input indicating selection of a virtual footrest mode, to apply a first predetermined force, above the normal force in normal driving mode, so as to remain in a footrest position, supporting the foot, then on receiving an input (e.g. from the throttle pedal travel sensor) indicating that the pedal has been depressed beyond the footrest position (or beyond a threshold amount beyond the footrest position), to gradually, over a predetermined time period, reduce the resistive force to a normal level. This can avoid excessive throttle pedal travel, if the force was immediately switched off, or rapidly decreased and avoid the response being uncomfortably heavy, if it continued to apply the same resistive force throughout the pedal travel range. Of course, the “normal” level may be zero, or may be dependent on a pedal weight setting and other factors, such as kick-down or ICE force indent. 
     Having returned to normal operation, if the controller does not receive an input indicating that the virtual footrest has been cancelled, upon reaching the rest position, the controller may re-apply the first predetermined force, so as to act as a footrest once again. The controller may also gradually reduce the resistive force to a normal level over a predetermined time period, in response to an input signal indicating that the virtual footrest mode has been deactivated (including for example a signal indicating that cruise control, or autonomous driving mode has been deactivated). 
     The throttle pedal assembly may comprise a pendulum-mounted throttle pedal, i.e. a throttle pedal that is mounted at the top, with a step plate below the mount. 
     The throttle pedal may be connected to the mount via an axle, for example by way of a plate portion, such as an annular plate portion of the throttle pedal distal from the step plate. The axle may be irrotatably attached to the throttle pedal, but rotatable with respect to the mount. The rotatable axle may be attached to the friction plate via the one-way bearing. The electromagnet may be irrotatably attached to the mount. This may allow the friction plate to rotate relative to the mount in one direction (when a depressive force is applied by a driver to the throttle pedal, such that if active, the electromagnetic brake applies a resistive force), but to rotate relative to the throttle pedal in the opposite direction (when returning under the force of the bias away from the depressed position), so that the electromagnetic brake does not affect recoil. 
     As an alternative to a pendulum mounted throttle pedal, the throttle pedal assembly may comprise a floor mounted throttle pedal (i.e. a pedal attached such that the mount is beneath the step-plate, beneath it, generally being pivotable from the front). 
     The throttle pedal assembly may comprise a linkage linking the step plate to the mount. The biasing member may be provided between the mount and the step plate, so as to act directly on the step plate, or between the mount and the linkage, so as to act on the linkage (which may optionally comprise a plurality of rotatably mounted links). 
     The linkage may be mounted to an axle, for example mounted eccentrically on a plate (such as a circular plate) fixed to an axle. The axle may rotate in the mount. 
     The axle may be irrotatably attached to the throttle pedal, but rotatable with respect to the mount. The rotatable axle may be attached to the friction plate via the one-way bearing. The electromagnet may be irrotatably attached to the mount. This may allow the friction plate to rotate relative to the mount in one direction (when a depressive force is applied by a driver to the throttle pedal, such that if active, the electromagnetic brake applies a resistive force), but to rotate relative to the throttle pedal in the opposite direction (when returning under the force of the bias away from the depressed position), so that the electromagnetic brake does not affect recoil. 
     The pedal travel sensor may comprise two portions, one mounted to the mount, the other mounted to throttle pedal, for example to the plate (i.e. the plate portion of a pendulum throttle pedal or the plate to which the linkage of a floor mounted throttle pedal is attached). Thus, relative movement between the two portions may be monitored by the controller to determine the extent of pedal travel. 
     The invention also extends to a vehicle comprising the throttle pedal assembly of the first aspect of the invention, optionally including any optional features or combination thereof. The vehicle may be an automobile. The vehicle may be a hybrid vehicle. The vehicle may have an automatic transmission. Alternatively the vehicle may have a manual transmission. 
     A second aspect of the invention comprises a throttle pedal controller operable to receive input signals and output an electromagnetic brake control signal, in dependence on the input signals; the electromagnetic brake control signal being an output voltage selected so as to adjust the force required to depress a throttle pedal. The controller may comprise any of the optional features set out in relation to the controller defined above. 
    
    
     
       DETAILED DESCRIPTION OF THE INVENTION 
       In order that the invention may be more clearly understood one or more embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which: 
         FIG. 1  shows a vehicle comprising a throttle pedal assembly; 
         FIG. 2  shows a schematic side view of a throttle pedal assembly according to a first embodiment of the invention; 
         FIG. 3  shows a cross section along the line A-A of  FIG. 1 ; 
         FIG. 4  shows a schematic side view of a throttle pedal assembly according to a second embodiment of the invention; 
         FIG. 5  shows a cross section along the line A-A of  FIG. 4 ; 
         FIG. 6  shows a schematic side view of a throttle pedal assembly according to a third embodiment of the invention; 
         FIG. 7  shows a cross section along the line A-A of  FIG. 6 ; 
         FIG. 8  shows a diagram of the controller provided in the throttle pedal assemblies of  FIGS. 1-7  and its inputs/outputs; and 
         FIG. 9 a    shows an enlarged schematic cross sectional view of the connection between the mounting plate and the friction plate of the throttle assembly of  FIGS. 2 and 3  with the electromagnet activated; 
         FIG. 9 b    shows an enlarged schematic cross sectional view of the connection between the mounting plate and the friction plate of the throttle assembly of  FIGS. 2 and 3  with the electromagnet deactivated; and 
         FIG. 9 c    show a diagrammatic view of the connection in  FIGS. 9 a  and 9 b    in particular showing the arrangement of the attachment points. 
     
    
    
     With reference to  FIG. 1 , a vehicle is shown. In this example, the vehicle is a hybrid automobile  1  having an automatic transmission. The vehicle  1  comprises a human machine interface  2 , in the form of a touchscreen, which is able to act as a visual output device and also an input device to receive input signals from a driver. The HMI  2  is operably connected to an onboard computer  3  (which of course may be a plurality of control units, e.g. to control different aspects, such as the internal combustion engine and the electric motors in the hybrid vehicle  1 ). The HMI  2  and onboard computer  3  are each operably connected to a controller  21 , in the form of a CPU equipped with memory and programmed to operate as described below. The controller  21  is provided in a throttle pedal assembly  4 ,  22 ,  41 , which is of any one of the throttle pedal assemblies  4 ,  22 ,  41  described below with reference to  FIGS. 2-7 . 
     The throttle pedal assembly  4  of the first embodiment of the invention is shown in  FIGS. 2 and 3 . This throttle pedal assembly  4  comprises a pendulum throttle pedal  5 , depending from, and rotatably mounted to, a mount  6 . The mount, in turn, is fixed in any known fashion to the body of the vehicle  1  (shown in  FIG. 1 ). As is conventional, the throttle pedal  5  comprises a step plate  7  at its proximal end, arranged so as to be depressed by a driver&#39;s foot. The distal end of the throttle pedal  5  is formed into a generally annular plate portion  8 , with its central aperture irrotatably attached to an axle  9 , which extends through the mount  6 , supported by a plain bearing  10  for rotation with respect to the mount  6 . 
     A biasing member  11  in the form of a compression spring extends between a portion of the pedal  5  (in this case a bulge from the plate portion  8 ) and a portion of the mount  6 , so as to bias the throttle pedal  5 , and in particular the step plate  7 , towards a rest position. 
     The mount  6  is U-shaped, formed from first and second plate-like limbs connected by a web at the top (which in use is fixed to the body of the vehicle  1 ). The axle  9  extends through the first plate like limb (right hand side in  FIG. 3 ). A pedal travel sensor is provided, and is made up of a first portion  12 , for example an optical sensor portion provided on the inside surface of the second limb of the mount  6  (left hand side in  FIG. 3 ), arranged to sense the position of a second portion  13  of the sensor, e.g. a marker portion, which is arranged on the plate portion  8  of the throttle pedal  5  opposite the first portion. Alternatively a Hall effect sensor could be used, for example a CIPOS® sensor available from Hella® 
     An electromagnetic brake  14  is provided on the side of the throttle pedal assembly  4  where the axle  9  extends. The electromagnetic brake  14  is provided by an electromagnet  15  and a friction plate  16 . The electromagnet  15  of this embodiment is annular and is provided in the outside surface of the first limb (radially outwardly of the axle  9  and the plain bearing  10 ). The friction plate  16  is also annular and arranged facing, but separated by a small air gap from, the electromagnet  15 . 
     The friction plate  16  is mounted to the axle  9 , to which the throttle pedal  5  is irrotatably attached. The friction plate  16  is mounted to a mounting plate  17 , such that in the absence of an attractive force from the electromagnet, a spring shim  60  (shown in  FIGS. 9 a -9 c   ) holds the friction plate  16  against the mounting plate  17 , separate from the electromagnet  15  (as shown in  FIG. 9 b   ). The mounting plate  17  is, in turn, irrotatably attached to the outer race of a one-way bearing, in the form of a sprag clutch  18 . The inner race of the sprag clutch  18  is attached (irrotatably) to the axle  9 . The sprag clutch  18  is arranged so as to allow free movement of axle  9  (and hence the throttle pedal  5 ) relative to the mounting plate  17  in a first direction  19  towards the rest position (to which the biasing member  11  biases the throttle pedal  5 ). On the other hand, the sprag clutch  18  is arranged to engage between the axle  9  and the mounting plate  17  when the throttle pedal  5  is depressed in the opposite direction  20 , against the bias (by a driver&#39;s foot). Thus, when the throttle pedal  5  is depressed, the friction plate  16  rotates relative to the electromagnet  15 , whereas when the throttle pedal is biased back to the rest position, the friction plate  16  is not caused to rotate relative to the electromagnet  15 . 
       FIGS. 9 a -9 c    show how the friction plate  16  is mounted to the mounting plate  17  by means of the spring shim  60 . The spring shim  60  is attached at three equidistant friction plate attachment points  61  (120 degrees apart) to the friction plate  16  and at three mounting plate attachment points  62  equidistantly spaced between the friction plate attachment points (120 degrees from each other), such that the shim  60  to friction plate and mounting plate attachment points  61 ,  62  are offset by 60 degrees in order to provide rotational torque transmission between the friction plate  15  and the mounting plate  17  while allowing a small radial displacement by means of the spring shim  60  bending. When the electromagnet  15  is energised (as shown in  FIG. 9 a   ) it provides an attractive force to the friction plate  16  opposing the elastic force of the spring shim  60 , to pull the friction plate  16  away from the mounting plate  17  across the air gap and against the electromagnet  15 , such that the friction plate  16  bears against the electromagnet with a force proportional to the strength of the electromagnetic force. This friction between the friction plate  16  and the electromagnet  15  opposes rotation of the friction plate  16 , thereby resisting rotation of the mounting plate  17  and hence the axle  9  to which the pedal  7  is attached. In consequence energising the electromagnet  15  increases the force required to depress the pedal  5 , and the higher the voltage applied to the electromagnet  15 , the greater the attractive force, and hence the greater the force required to overcome the force retarding depression of the pedal  5 . 
     The throttle pedal assembly  4  further comprises a controller  21  shown schematically in  FIGS. 2 and 3 , which controls the operation of the electromagnet  15  on the basis of various inputs. The general operation of the controller is the same regardless of the specific form of the throttle pedal assembly  4 , so it will be described in detail below, following the description of two alternative embodiments of throttle pedal assemblies. 
     The throttle pedal assembly  22  of the second embodiment of the invention is shown in  FIGS. 4 and 5 . This throttle pedal assembly  22  comprises a floor mounted or “organ stop” throttle pedal  23  pivotally mounted at its front (left hand side in  FIG. 4 ) to a mount  24 . The mount  24 , in turn, is fixed in any known fashion to the body of the vehicle  1  (shown in  FIG. 1 ). As is conventional, the throttle pedal  23  comprises a step plate  25 , with an upwardly and forwardly facing surface to be depressed by a driver&#39;s foot. The underside of the throttle pedal  23  includes a bracket  26 , to which one end of a linkage  27  in the form of an input rod is pivotably mounted. The opposite end of the linkage  27  is pivotably attached to a crank  28 , which is a generally annular plate, with its central aperture irrotatably attached to an axle  29 , which extends through the mount  24 , supported by a plain bearing  30  for rotation with respect to the mount  24 . 
     A biasing member  31  in the form of a compression spring extends between the underside of the pedal  23  (in this case a bracket thereon) and a portion of the mount  24 , so as to bias the throttle pedal  23 , and in particular the step plate  25 , towards a rest position. 
     The mount  24  has a flat base for connection to the floor of the vehicle, with a generally triangular body extending therefrom. The axle  29  extends through the triangular body. A pedal travel sensor is provided, and again includes a first portion  32 . This first portion  32  is provided on the inside surface of a hood extending from the top of the generally triangular body of the mount  6  over the top part of the crank  28  (left hand side in  FIG. 5 ). It is arranged to sense the position of a second portion  33  of the sensor which is arranged on the opposing surface of the crank  28 , towards its top. 
     As in the first embodiment, an electromagnetic brake  34  is provided on the side of the throttle pedal assembly  22  where the axle  29  extends. The electromagnetic brake  34  is provided by an electromagnet  35  and a friction plate  36 . The electromagnet  35  is annular and is provided in the other side of the triangular body to the side on which the crank  28  and sensor  32 ,  33  is found (radially outwardly of the axle  29  and the plain bearing  30 ). The friction plate  36  is also annular, and is arranged facing, but separated by a small air gap from the electromagnet  35 . 
     The friction plate  36  is mounted to the axle  29 , to which the throttle pedal  23  is irrotatably attached. The friction plate  36  is mounted by means of a mounting plate  37 , which is irrotatably attached to the outer race of a one-way bearing, in the form of a sprag clutch  38 . (The friction plate  36  is mounted to the mounting plate  37  by means of a sping shim (not shown) in exactly the same manner as the first embodiment.) The inner race of the sprag clutch  38  is attached (irrotatably) to the axle  29 . The sprag clutch  38  is arranged so as to allow free movement of axle  29  (and hence the throttle pedal  22 ) relative to the mounting plate  37  in a first direction  39  towards the rest position (to which the biasing member  31  biases the throttle pedal  23 ). On the other hand, the sprag clutch  38  is arranged to engage between the axle  29  and the mounting plate  37  when the throttle pedal  23  is depressed in the opposite direction  20 , against the bias (by a driver&#39;s foot). Thus, when the throttle pedal  23  is depressed, the friction plate  36  rotates relative to the electromagnet  35 , whereas when the throttle pedal is biased back to the rest position, the friction plate  36  is not caused to rotate relative to the electromagnet  35 . 
     When the electromagnet  35  is energised it provides an attractive force to the friction plate  36  bringing it into frictional engagement with the electromagnet and thus resisting its rotation. In consequence energising the electromagnet  35  increases the force required to depress the pedal  23 , and the higher the voltage applied to the electromagnet  35 , the greater the attractive force, and hence the greater the force required to overcome the force retarding depression of the pedal  23 . 
     The throttle pedal assembly  22  further comprises a controller  21  shown schematically in  FIG. 4 , which controls the operation of the electromagnet  35  on the basis of various inputs. The general operation of the controller is the same regardless of the specific form of the throttle pedal assembly  4 , so it will be described in detail below, following the description of a third exemplary embodiment of a throttle pedal assembly. 
     The throttle pedal assembly  41  of the third embodiment of the invention is shown in  FIGS. 6 and 7 . Like the second embodiment, this throttle pedal assembly  41  comprises a floor mounted or “organ stop” throttle pedal  42  pivotally mounted at its front (left hand side in  FIG. 6 ) to a mount  43 . Many parts are the same as in the second embodiment and like numerals are used for like parts. The mount  43  is fixed in any known fashion to the body of the vehicle  1  (shown in  FIG. 1 ). The throttle pedal  42  again comprises a step plate  44 , with an upwardly and forwardly facing surface to be depressed by a driver&#39;s foot. The underside of the throttle pedal  42  includes a bracket  45 , to which one end of a linkage  46  is pivotably mounted. 
     The main difference between the second and third embodiments is simply in the linkage, which in this third embodiment comprises a series of three links  47 ,  48 ,  49 , the first link  47  being straight, pivotally connected at one end to the bracket  45  and pivotally connected at the opposite end to the second link  48 ; the second link being right-angled, pivotally connected at one end to the first link  47 , as mentioned, pivotally connected at the opposite end to the third link  49 , and, pivotally mounted at the corner, between the two ends, to an upwardly extending portion  50  of the mount  43 , so as to translate downward pressure on the throttle pedal  42 , and downward motion of the first link  47  into lateral motion of the third link  49 . The opposite end of the third link  49  to that connected to the second link  48  is pivotably attached to a crank  28 , which is a generally annular plate, with its central aperture irrotatably attached to an axle  29 , which extends through the mount  43 , supported by a plain bearing  30  for rotation with respect to the mount  24 . 
     Another aspect of the third embodiment which differs from the second is that a biasing member  5  in the form of a compression spring extends between the linkage  46  and a portion of the mount  43 , in particular, between a triangular body extending from the flat base of the mount  43  and the region where the second and third links are connected, so as to bias the throttle pedal  42 , and in particular the step plate  44 , towards a rest position. 
     As in the second embodiment, the mount  42  has a flat base for connection to the floor of the vehicle, with a generally triangular body extending therefrom. The axle  29  extends through the triangular body. A pedal travel sensor is provided, and again includes a first portion  32 , which is provided on the inside surface of a hood extending from the top of the generally triangular body of the mount  42  over the top part of the crank  28  (left hand side in  FIG. 7 ). It is arranged to sense the position of a second portion  33  of the sensor which is arranged on the opposing surface of the crank  28 , towards its top. 
     Exactly as in the second embodiment, an electromagnetic brake  34  is provided on the side of the throttle pedal assembly  41  where the axle  29  extends. Like numbers refer to like parts in the figures, so this is described in no more detail here—we simply refer to the paragraphs above. 
     Like the other throttle pedal assemblies described, the throttle pedal assembly  41  of the third embodiment further comprises a controller  21  shown schematically in  FIG. 6 , which controls the operation of the electromagnet  35  on the basis of various inputs. The general operation of the controller is the same regardless of the specific form of the throttle pedal assembly  4  and described in detail below. 
     The operation of the controller  21  in the hybrid electric automatic automobile  1  of  FIG. 1  and any of the first to third embodiments of throttle pedal assemblies  4 ,  22 ,  41  is described with reference to  FIG. 8 . 
     The controller  21  is a CPU comprising a processor  52  and memory  53 , it receives a number of inputs and transmits certain outputs, primarily an electromagnetic brake control signal, in the form of a variable output voltage, which is outputted to the electromagnetic brake  14 / 34  of the throttle pedal assembly  4 / 22 / 41 . The primary inputs are a throttle pedal position signal from the first portion  12 / 32  of the throttle pedal position sensor, a user input from the HMI  2  and an engine control input from the onboard computer  3 . 
     The processor  52  of the controller  21  is programmable to operate in different manners depending on how it is setup, for example by the manufacturer in dependence on the characteristics of the vehicle that it is installed in. For example, if, rather than an automatic vehicle  1 , the controller was installed in a manual vehicle, it would not need to perform a “kickdown” function. Similarly, in a vehicle without cruise control/autopilot or the like, it would not need to perform a “virtual footrest” function; in a vehicle with only an internal combustion engine, it would not need the “ICE indent” function. Likewise, manufacturers may choose to install a throttle pedal assembly  4 ,  21 ,  41  in all vehicles to reduce inventory, but to turn off certain features in certain vehicles (e.g. bottom of the range models), or to activate features as an option—thus, for example, the setup could determine whether pedal weight is customisable or not, or whether it is customisable by calibration, by choice between settings, in dependence on seat position, or each of these, depending on a choice made through the HMI  2 . 
     For the sake of this description of an embodiment, the controller  21  is set up to have a customisable pedal weight, based on a choice made through the HMI  2 , and to perform the kickdown, virtual footrest and ICE indent functions. 
     Starting with customisable pedal weight, the HMI  2  is capable of displaying a selectable “settings” menu on the (touch) screen. When selected, e.g. by touching the relevant area of the screen, a selectable “pedal weight” option is displayed. When selected, the “pedal weight” option displays three selectable options for pedal weight: “pre-set”, “automatic”, or “calibrated”. Selecting “pre-set” provides three selectable options “light”, “medium” and “firm”. 
     When a user selects “light”, a corresponding (i.e. “light”) pedal weight signal is sent by the HMI  2  to the controller  21 . The processor  52  interprets this signal to mean that no extra weight should be applied to the pedal to account for the desired pedal weight, so no additional voltage is applied to the electromagnetic brake control signal sent to the electromagnetic brake to correspond to the desired pedal weight. This “light” setting is saved to memory  53  and used unless overwritten by a different setting received from the HMI. 
     If, the user selects “medium”, a corresponding pedal weight signal is sent to the processor  52  of the controller  21 , saved to memory  53  and in consequence wherever the throttle pedal is positioned, the controller outputs an additional voltage as the electromagnetic brake signal to the electromagnetic brake  14 / 34  to provide a resistive force corresponding to an extra “medium” force, required to depress the pedal. The “medium” signal is saved to memory  53  and used unless overwritten. 
     In the event that “firm” is selected, the controller  21  receives this signal and outputs an additional voltage corresponding to a higher resistive force, hence further increasing the force required to depress the pedal. Again, this signal is saved and used unless overwritten. 
     If, rather than the “pre-set” option, a user selects “automatic”, the controller receives this signal, determines the seat position from a seat position signal output from the onboard computer  3 , in which all the way forward is “minimum” and all the way back is “maximum”, and saves the position to memory. The position between minimum and maximum is taken to correspond to the amount of additional voltage to apply to the electromagnetic brake signal. 
     If, instead, the user selects “calibrated”, the HMI  2  sends a calibration signal to the controller  21 , which applies maximum resistive force via the output voltage to the electromagnet brake  14 / 34 . The HMI  2  then outputs an instruction to the driver to rest his/her foot on the pedal and relax the leg as if using a foot rest. The output voltage to the electromagnetic brake  14 / 34  is then reduced gradually, whilst the controller  52  simultaneously monitors the throttle pedal position sensor  12 / 32  until it indicates that the pedal is starting to move. This tells the system how much force the driver applies without actually pushing on the pedal. This driver specific data would then be used to determine the optimum pedal weight setting, as well as set the optimum force characteristics for ‘kick down’, ‘active pedal’, ‘footrest’, and any other features that employ the electromagnetic pedal haptic control system. An additional voltage corresponding to a force corresponding to that at which the pedal began to move can be added throughout pedal motion, with the driver specific setting being saved to memory  53 , and the controller  52  outputting a signal to the HMI to display an indication that the pedal weight has been calibrated. 
     It will be noted above that an “additional” voltage is described in relation to the pedal weight options above. This additional voltage is output regardless of the position of the pedal. In this embodiment, the control signal further comprises a standard variable voltage to which the additional voltage (based on pedal weight) is added—the standard variable voltage varying based on further inputs and the mode of operation, as described below. 
     In an ordinary driving mode (not cruise control/autonomous driving etc.), the onboard computer  3  receives an indication of the throttle pedal position from the sensor  12 / 32  and controls the power to the vehicle  1  accordingly. At the top of the throttle pedal motion, nearest the rest position, since the vehicle is hybrid, providing there is sufficient battery power, the power is provided by the batteries, with the vehicle being propelled by motors. Under these conditions, the return force of the pedal (towards the rest position) is solely the result of the force of the biasing member  11 ,  31 ,  51  plus any additional voltage based on the pedal weight setting described above. 
     The onboard computer  3  continuously monitors the power required of the battery to assess when the ICE will need to be activated if more power is demanded by the user (by pressing further on the throttle pedal)—this can occur at varying throttle (hence pedal position) as a result of environmental and system parameters. Accordingly, the onboard computer  3  outputs a signal to the controller  21  when the pedal position is close to the maximum available throttle in “E” mode, say 5 degrees from triggering the ICE to start. On receipt of this “Max E Power” signal, the controller the electromagnetic brake output signal, increasing the standard variable voltage at this position and beyond (but gradually reducing the additional voltage over time to avoid discomfort), so as to provide an “ICE indent” to indicate to the driver that if he/she does not push past the associated throttle position, the vehicle can remain in “E” mode, which is normally more economical. 
     Beyond the throttle pedal position at which the ICE starts (“the ICE indent”) the electromagnetic brake output signal remains normal (based on the additional voltage for pedal weight), to the point of 100% ICE throttle in the given gear chosen by the automatic gearbox. This can be a fixed position of the throttle pedal, corresponding to a fixed position sensed by the throttle pedal position sensor  12 / 32 . The processor  51  of the controller  21  monitors when this position is reached and, to replicate the “kickdown” function, at this point (where continued pressing on the pedal will cause the automatic gearbox to downshift), and beyond to the full extend of pedal travel, the controller modifies the electromagnetic brake output signal, increasing the standard variable voltage output so that the total output voltage (including the additional voltage associated with pedal weight setting) is increased and hence the resistive force and force required to depress the pedal is increased, thereby replicating the kickdown function, alerting the driver that this continued pressing on the accelerator results in a downshift to provide more acceleration. 
     Finally, if (e.g. via the HMI  2 ) autonomous driving mode, or cruise control is selected, and the driver selects a “virtual footrest” mode, the throttle pedal must still be fully functional as a throttle pedal as is the case with existing cruise control functions. However, the controller  21  on receiving the virtual footrest mode signal will output a substantially increased standard variable voltage as the “footrest” electromagnetic brake signal, such that this voltage, plus any additional voltage from the pedal weight setting will hold the pedal in position to support the foot. Due to the increased pedal force that is required in order to provide the footrest function, the throttle pedal would be uncomfortably heavy if the electromagnetic brake  14 / 34  continued to apply the same braking force throughout the whole pedal travel range while in footrest mode. Accordingly, the processor  52  of the controller  21  continues to monitor the throttle pedal position sensor  12 / 32  and if a throttle pedal movement above a pre-determined threshold is detected while in footrest mode, then it is assumed that the driver wishes to accelerate the vehicle, in which case the footrest electromagnetic brake signal and corresponding substantially increased standard variable voltage will gradually reduce to zero in order to provide a transition to a normal pedal force/travel ratio, and hence provide a more comfortable throttle pedal function. If the electromagnetic brake force was simply switched off or reduced too quickly it would result in excessive throttle pedal travel and hence unwanted vehicle acceleration. The footrest mode is linked to the cruise control/autonomous driving mode and will remain ‘switched on’ until either the footrest mode, or corresponding cruise/autonomous driving mode is deactivated (which will be detected as a signal from the HMI  2  or onboard computer  3 ). If deactivation is not detected, once the controller  21  detects from the sensor  12 / 32  that the pedal as returned to the rest position, the increased standard variable voltage will be reapplied to reactivate the virtual footrest. 
     The above embodiments are described by way of example only. Many variations are possible without departing from the scope of the invention as defined in the appended claims.