WO2017140366A1

WO2017140366A1 - Shifter assembly for shifting a vehicle transmission

Info

Publication number: WO2017140366A1
Application number: PCT/EP2016/053458
Authority: WO
Inventors: Laura Kvarnstrand
Original assignee: Kongsberg Automotive Ab
Priority date: 2016-02-18
Filing date: 2016-02-18
Publication date: 2017-08-24

Abstract

The present invention is directed to a shifter assembly for shifting a vehicle transmission having a rearward drive state and at least one forward drive state, said shifter assembly comprising : a shifter (21) moveable between shift positions including a rearward driving position (R) and at least one forward driving position (D; 1, 2, 3, 4, 5, 6) corresponding to the rearward drive state and the at least one forward drive state, respectively, of the vehicle transmission; a control unit (20) arranged to be connectable to a surroundings monitoring system (14, 16, 18) capable of detecting obstacles in front of and behind the vehicle, wherein the control unit (20) is arranged to prevent shifting of the vehicle transmission to the rearward drive state or to one of the at least one forward drive if an obstacle behind or in front of the vehicle is detected, respectively; characterized in that a mechanical locking mechanism or an adaptive braking mechanism (10, 12, 46) for blocking movement of the shifter (21) from a current to a new shift position is provided, and in that said preventing of shifting of the vehicle transmission state is performed by the control unit (20) which is arranged to operate the mechanical locking mechanism or the adaptive braking mechanism (10, 12, 46) to block movement of the shifter (21) to the rearward driving position if an obstacle behind the vehicle is detected, and to block movement of the shifter (21) to the at least one forward driving position if an obstacle in front of the vehicle is detected by the surroundings monitoring system.

Description

Shifter assembly for shifting a vehicle transmission

The present invention is directed to a shifter assembly for shifting a vehicle transmission having a rearward drive state and at least one forward drive state, said shifter assembly comprising : a shifter moveable between a plurality of shift positions in^¬ cluding a rearward driving position and at least one forward driving position corresponding to the rearward drive state and the at least one forward drive state, respectively, of the ve^¬ hicle transmission; a control unit arranged to be connectable to a surroundings monitoring system capable of detecting an obstacle in front of and behind the vehicle, wherein the control unit is arranged to prevent shifting of the vehicle transmission to the rear^¬ ward drive state if an obstacle behind the vehicle is detect^¬ ed, and to prevent shifting of the vehicle transmission to one of the at least one forward drive states if an obstacle in front of the vehicle is detected.

A shifter assembly of this kind is disclosed in US 6 674 360 B2. In the embodiment described a shift lever is moveable to shift positions P, R, N, and D of an automatic transmission. Of course the same disclosure could be applied to a shifter assembly including gears 1 to 6 forward and a rearward gear of a manual transmission. The shifter assembly includes a control unit connected to a surroundings monitoring system. In this document the surroundings monitoring system comprises a front camera and a rear camera. The front camera monitors a prede^¬ termined area in front of the vehicle, wherein the images are processed using a pattern recognition method to identify moving (e.g. pedestrians) or stationary objects in the predeter^¬ mined area in front of the vehicle. If such object is identi^¬ fied it is concluded that there is an object in front of the vehicle, which means within the predetermined area, either di^¬ rectly in front of the vehicle or at a certain distance within the predetermined area captured by the front camera. The same applies in a corresponding manner to the rear camera. The control unit is arranged to determine whether movement of the ve^¬ hicle in the intended direction of travel is obstructed by an object detected, and if this is the case it invalidates the operational signal to the transmission so that the transmis^¬ sion is actually not shifted. For example, when an object is detected in front of the vehicle the control unit prohibits the transmission to be shifted to D even if the shifter is moved to the D shift position, i.e. the vehicle does not start to move forward although the driver moved the shifter to D be^¬ cause the command to the transmission to change over to D is ignored. In such a situation the control unit activates a warning device to alert the driver, wherein the preferred warning device described is a buzzer. As an alternative warn^¬ ing device a vibration mechanism is mentioned which when activated causes vibration of the shifter to inform the driver that shifting of the shifter to the shift position to which it was moved did not result in a corresponding shift of the transmission state.

It is an object of the present invention to improve a shifter assembly for a vehicle transmission, which shifter assembly receives input from a surroundings monitoring system to pre^¬ vent shifting of the transmission to a driving state if an obstacle is detected by the surroundings monitoring system for this driving state, in such a manner that a driver receives an intuitively clear and easily perceivable feedback, that the transmission cannot be shifted to the intended forward or rearward drive state. This object is achieved by the shifter assembly comprising the features of claim 1. Preferred embodiments of the invention are set out in the dependent claims.

According to the present invention, a mechanical locking mechanism or an adaptive braking mechanism for blocking movement of the shifter to an adjacent shift position is provided. The mechanical locking mechanism may for example comprise a movea^¬ ble locking element which is moveable under the control of the control unit and which can be moved to intersect the movement path of a portion of the shifter such that the locking element blocks movement of the shifter to an adjacent shift position. Alternatively, an adaptive braking mechanism is utilized which is controlled by the control unit and which can generate a high braking force under the control of the control unit such that the shifter is arrested and blocked from movement to an adjacent shift position. Such adaptive brake mechanism may for example utilize field-responsive smart fluids, for example, magneto-rheological fluids or electro-rheological fluids, wherein magneto-rheological fluids have properties, for exam^¬ ple, apparent viscosity and yield stress which are variably controllable via exposure to external magnetic fields, and wherein electro-rheological fluids have properties, for exam^¬ ple apparent viscosity, which are variably controllable via exposure to external electric fields. In response to an ap^¬ plied field, the named smart fluids, in a relatively high ap^¬ parent viscosity state, can therefore exert drastically in^¬ creased shear forces on a component connected to the shifter, thus causing a high braking force on the shifter. Further details on design and operation of magnet-rheological fluid braking mechanisms can be found in US 2013/0175132 Al .

The control unit is arranged to activate the mechanical lock^¬ ing mechanism or the adaptive braking mechanism to block movement of the shifter to the rearward driving position if an ob- stacle behind the vehicle is detected, and to block movement of the shifter to the at least one forward driving positions if an obstacle in front of the vehicle is detected by the sur^¬ roundings monitoring system.

By preventing movement of the shifter to an unsafe driving position, i.e. to a driving position in a driving direction in which an obstacle is detected which could result in a colli^¬ sion, it is on the one hand achieved that the transmission is not shifted to the transmission state corresponding to the unsafe shifting position because the shifter could not reach this unsafe driving position and therefore no command to the transmission could be generated to change the transmission state to the transmission state corresponding to the unsafe driving position. On the other hand, by blocking movement of the shifter to the unsafe driving position the driver is immediately and directly informed that the intended shift movement could not be carried out. This provides the driver with an in^¬ tuitively clear and easily perceivable tactile feedback that the intended shift operation was unsuccessful and that no shift of the transmission state of the transmission could be achieved .

In a preferred embodiment the control unit is arranged, if an obstacle has been detected and moving of the shifter to an in^¬ tended driving position is blocked, to allow the driver to override this blocking of the shifter by releasing the mechanical locking mechanism or the adaptive braking mechanism if at least one of the following conditions is fulfilled: (i) the blocking is released after a predetermined period of time ex^¬ pired, whereafter the driver is able to move the shifter to the intended driving position; (ii) if the force exerted by the driver on the shifter towards the blocked driving position exceeds a threshold value; (iii) if an override button is pressed by the driver, or (iv) an accepted voice command is given. This override option enables the driver to reach the intended driving shift position even though an obstacle has been detected for this driving position, and therefore enables the driver after first noticing the blocking of the shifter to check for any obstacle causing this blocking, and to override the blocking if the driver recognizes that there is an uncrit^¬ ical obstacle only, for example tall grass, or cardboard, etc. which would not cause damage if the vehicle is driving in the direction of such obstacle.

In a preferred embodiment the shifting positions of the shift^¬ er are indicated in a shift menu display showing symbols for the shift positions which are available by operating the shifter to get to a shifting state which corresponds to one of the displayed symbols. The shift menu can for example be dis^¬ played by a pattern of shift positions wherein at each shift position a symbol is displayed which represents the shifting position, for example D, P, N, R.

In a preferred embodiment the control unit is arranged, if an obstacle has been detected and operating of the shifter to an intended shifting position is blocked, to alter the shift menu display for the symbols of shift positions to which movement has been blocked by turning off the symbols in the shift menu display of such driving position symbols such that such symbols become invisible, or by altering the symbols or their background to include a warning attribute such as fading, flashing or with a warning color, for example in red.

In addition to the blocking of the shifter against movement to an unsafe driving position, displaying the shifting position symbols next to the shifter or on the shifter or on any other corresponding driver display, for unsafe driving positions with a warning attribute such as faded, flashing or shown with a warning color, gives an intuitively clear visible feedback as to which driving position is unsafe and blocked. Alterna^¬ tively, by turning off symbols of driving positions that are unsafe such that the symbols become invisible is also intui^¬ tively very clear since in this manner only the symbols of safe driving positions are displayed and presented to the driver as available options.

In a preferred embodiment the control unit may in addition be arranged, if an obstacle has been detected and operating of the shifter to an intended shifting position is blocked, to alter the shift menu display regarding the symbols for the shift positions to which movement of the shifter has not been blocked by displaying such symbols or their background in a color indicating a safety confirmation, for example in green.

In a preferred embodiment the control unit is arranged to de^¬ termine whether a parking brake is applied, and if so to acti^¬ vate the mechanical locking mechanism or the adaptive brake mechanism to block movement of the shifter to the rearward and forward driving positions and to alter the shift menu display of the symbols of these driving positions by turning off the display of such driving positions symbols such that the sym^¬ bols become invisible, or by altering the symbols or their background to include a warning attribute such as fading, flashing or a warning color, for example red. In this manner the driver receives an intuitively clear and easily perceiva^¬ ble feedback that none of the rearward and forward driving po^¬ sitions is available as long as the parking brake is applied.

In a preferred embodiment an acoustic warning signal generator is provided and the control unit is arranged, if an obstacle has been detected and moving the shifter to a shifting posi^¬ tion in a driving direction corresponding to the direction of the detected obstacle is blocked, to activate the acoustic warning signal generator to produce an acoustic warning sig- nal . This, in addition to the physically blocked shifter, which cannot be moved to the intended shifting position, alerts the driver that he or she attempted to move the shifter to an unsafe driving position.

In a preferred embodiment the surroundings monitoring system is arranged to be able to detect moving obstacles and is ar^¬ ranged to predict the position of moving obstacles, wherein the surroundings monitoring system is arranged to signal pres^¬ ence to an obstacle in front of or behind the vehicle if the predicted position of the moving obstacle after a predetermined delay time would be in the driving path of the vehicle in front thereof or behind it, respectively. This allows the shifter assembly to take into account also moving obstacles which are not yet in the driving path, but likely will be an obstacle in front of or behind the vehicle in the driving path within a predetermined time so that a collision would be like^¬ ly. The predetermined delay time could be up to approximately ten seconds, for example. For longer delay times it is rather likely that the vehicle already started driving and passed the obstacle without collision.

The present invention can be implemented in connection with any surroundings monitoring system, for example radar or camera systems which are monitoring a region in front of and be^¬ hind the vehicle and optionally on the sides of the vehicle, wherein such imaging system cover a certain range for capturing objects, i.e. objects directly adjacent to the vehicle, in front of or behind it and objects at a certain distance in front of or behind the vehicle, wherein the distance is deter^¬ mined by the range of the monitoring system. The range of such camera or radar based imaging monitoring systems is typically set to be about a few meters . The invention will now be described with reference to an em^¬ bodiment illustrated in the drawings in which:

Fig. 1 shows a schematical perspective view of interior compo^¬ nents of a vehicle,

Fig. 2 shows a schematical side view of a vehicle with obsta^¬ cles in front of and behind the vehicle;

Fig. 3 shows a schematical cross-sectional view of an adaptive braking mechanism together with a block diagram of further components of the shifter assembly;

Figs. 4 and 5 show a flow chart illustrating the operation of an embodiment of the shifter assembly according to the present invention ;

Fig. 6A shows alternative shift menu displays for an automatic transmission in case an object is detected in front of the ve^¬ hicle but no object is detected behind;

Fig. 6B shows alternative shift menu displays for a manually shifted transmission in case an object is detected in front of the vehicle but no object is detected behind;

Fig. 7A shows alternative shift menu displays for an automatic transmission in case an object is detected behind the vehicle but no object is detected in front;

Fig. 7B shows alternative shift menu displays for a manually shifted transmission in case an object is detected behind the vehicle but no object is detected in front; Fig. 8A shows alternative shift menu displays for an automatic transmission in case objects are detected in front of and be^¬ hind the vehicle;

Fig. 8B shows alternative shift menu displays for a manually shifted transmission in case objects are detected in front of and behind the vehicle.

Fig. 1 shows a schematical perspective view of components of a vehicle interior around a driver seat of a vehicle. A shifter assembly, in this case a shift-by-wire shifter assembly, ena^¬ bles the driver to control a transmission by shifting between transmission states, for example between forward driving (D) , neutral (N) , rearward driving (D) , and parking (P) of an automatic transmission. In the exemplary embodiment shown in Fig. 1 the shifter assembly comprises a rotary knob 21 which is surrounded by a shift menu display 22 including symbols P, N, R, and D at the respective shift positions of the rotary knob 21. It should be noted, however, that the present invention can be utilized with any kind of shifter means, for example with a pivotal shift lever, a linear sliding shifter, press button shifters including press buttons for the various trans^¬ mission states, etc.. In addition, it should be noted that the present invention is not limited to shifter assemblies for au^¬ tomatic transmissions, but is also applicable to shifter as^¬ semblies for manually shifted transmissions comprising a rear^¬ ward driving state (R) and, for example, six forward driving states with gears 1 to 6.

Fig. 2 shows a schematical side view of a vehicle in which a shifter assembly according to the present invention may be implemented. The vehicle is equipped with a surroundings moni^¬ toring system including in this exemplary embodiment a front camera 14 and a rear camera 16. Side detection units may also be included. The present invention is not limited to monitor- ing systems based on cameras but can also be realized with any other monitoring systems using for example radar surveillance of regions in front of and behind the vehicle, or a full vehi^¬ cle perimeter zone surveillance.

The front and rear cameras 14, 16 are connected to a surround^¬ ings monitoring control unit 18 which is schematically indi^¬ cated in Figs. 2 and 3. The surroundings monitoring control unit 18 is equipped with data processors and is arranged to analyze images taken by the front and rear cameras 14, 16 with pattern and density recognition and pedestrian and vehicle trajectory algorithms. Based on this analysis, the surrounding monitoring control unit 18 is capable of identifying moving or stationary objects in the field of view of the front camera 14 and of the rear camera 18. In the example of Fig. 2 a low wall F is present in front of the vehicle, and another object R is present behind the vehicle. The surroundings monitoring system is capable of identifying objects which are located in a dis^¬ tance range in front of and behind the vehicle, i.e. objects that are located directly in front or behind the vehicle and objects that are located within a certain distance range in front of and behind the vehicle. In this manner, the surround^¬ ings monitoring system can detect objects which are disposed in the driving path if the vehicle would drive in a forward or rearward direction. The front camera 14 and the rear camera 16 may have a wide field of view such that regions outside of the direct travel path are covered. The surroundings monitoring control unit 18 can be arranged to execute algorithms which identify moving objects. Surroundings monitoring control unit 18 may be further arranged to predict the position of moving objects at a given time in the future, and may be further ar^¬ ranged to signal that an object is detected in front or behind the vehicle if the predicted position of such moving object is within the driving path within a predetermined time ahead. Such objects, which are predicted to be located in front of and/or behind the vehicle at a predetermined time in the fu^¬ ture, are signaled in the same way as objects detected immedi^¬ ately in front of and/or behind the vehicle.

If an object has been detected in this manner by the surround^¬ ings monitoring system this information is transmitted by the surroundings monitoring control unit 18 to a control unit 20 of the shifter assembly. If the vehicle is standing or moving at very low speed with the shifter in the park or neutral shift position, and the control unit 20 receives information regarding an object in front of or behind the vehicle, the control unit 20 is arranged to control a mechanical locking mechanism or an adaptive braking mechanism in such a manner that shifting of the shifter to a driving direction in which the object has been detected is blocked, i.e. the shifter can^¬ not be moved to such shifting position which would result in a driving direction towards the object detected.

In this exemplary embodiment shown in Fig. 3, an adaptive braking mechanism is shown which is used to block the shifter to a driving direction in which an object has been detected. Fig. 3 includes a cross-sectional view of the adaptive braking mechanism acting selectively on a shifter to arrest its move^¬ ment. In particular, Fig. 3 shows a shifter 21 in form of a rotary knob which is fixed to a shaft 40. Shaft 40 is mounted in a housing (not shown) so as to be rotatable around its lon^¬ gitudinal axis. A rotor 46 is fixed to the shaft 40. The rotor 46 is disposed within a housing 8 and is freely rotatable therein. At its outer periphery the rotor 6 projects into an annular chamber 10 within the housing 8, which chamber 10 is filled with a magneto-rheological fluid. Disposed adjacent to chamber 10, filled with magneto-rheological fluid, a coil 12 is provided in the housing 8. If electricity is supplied to the coil 12, a magnetic field is generated by the coil, which magnetic field penetrates the chamber 10 and the magneto- rheological fluid. In response to such a generated magnetic field, the viscosity of the fluid abruptly rises, and conse^¬ quently the shear forces of the magneto-rheological fluid in the chamber 10 drastically increase so that a high braking force is exerted on a rotor 6 and thus on the rotary knob which brings the rotary knob to a stop. For further details regarding design and operation of magneto-rheological brake mechanisms reference is made to US 2013/0175132 Al and US 9 091 309 Bl.

The control unit 20 also receives information from a sensor sensing the movement direction of the shifter. The control unit 20 can be arranged in such a manner that it periodically releases blocking of the shifter after very short time intervals. If the control unit releases the adaptive braking mecha^¬ nism and receives information from the sensor that it is still attempted to move the shifter towards the direction in which an object has been detected, shifter movement is blocked again by activating the magneto-rheological braking mechanism. This operation can be repeated at a very high frequency, wherein the activation of the magneto-rheological braking mechanism is only repeated as long as movement of the shifter towards a driving state in the direction in which an object has been detected continues. If no such movement attempt of the shifter towards the unsafe direction is detected or if movement of the shifter in the opposite direction is detected, and no object has been detected in this opposite direction, the control unit 20 ceases to activate the magneto-rheological fluid braking mechanism such that movement of this shifter to the opposite direction shift state in which no object has been detected is allowed by the control unit 20.

By releasing the adaptive braking mechanism at high frequency, and by checking whether movement of the shifter is still at^¬ tempted in the unsafe direction, wherein activation of the adaptive braking mechanism is repeated only if such movement attempt is found, the adaptive braking mechanism can be oper^¬ ated to act as a blocking mechanism which is effective only for blocking movement of the shifter in one direction, whereas the shifter is free to be moved in the opposite direction. As an alternative to an adaptive braking mechanism a simple me^¬ chanical locking mechanism may be used which includes a lock^¬ ing element, which may be moved into the movement path of a component connected to the shifter so that the component can^¬ not pass the component moved into the movement path, which blocks further movement of the shifter in one direction. By including several locking elements which may be selectively actuated by the control unit 20 selective blocking of shifter movements towards certain shift positions may be affected.

Figs. 4 and 5 show a flow diagram illustrating the operation of the control unit 20 in cooperation with the adaptive brak^¬ ing mechanism 10, 12, 46 and the shift menu display 22. At step 101 in Fig. 4 the driver starts the engine of the vehicle or wants to resume driving after parking with the engine running .

In step 102 control unit 20 communicates with surroundings monitoring control unit 18 of the surroundings monitoring sys^¬ tem and receives information whether, and if so, where objects have been detected in front of and/or behind the vehicle (step 103) .

If no objects have been detected in front of or behind the ve^¬ hicle, control unit 20 imposes no restrictions on movement of the shifter, i.e. the shifter can be moved to forward or rear^¬ ward driving directions as desired. In addition, the shift menu display is in its default state in which all shifting po^¬ sitions of the shifter are available, unlocked and displayed with their symbols in a fully visible and normal state. In the case of an automatic transmission, this would be a shifter menu with the symbols D, P, N, R, in the same normal state, all available, unlocked, and fully visible and without any flashing or other warning display mode for any of the symbols. In case of a manually shifted transmission this could be a shifter menu display including the symbols R, and 1 to 6 for six forward driving gears.

If it has been found in step 103 that at least one object has been detected in front of and/or behind the vehicle, control unit 20 determines in step 105 if there is only an obstacle front of the vehicle. If this state is confirmed to be true, control unit 20 carries out the actions indicated in block 106. In particular, control unit 20 activates the shifter braking mechanism such that movement of the shifter to a forward driving shift position is blocked. Preferably, this blocking of the shifter is overridable by the driver if the driver checked the area in front of the vehicle and recognized the detected obstacle as harmless. To provide the driver with the option to override the blocking the control unit 20 may be arranged such that the blocking is only maintained over a pre^¬ determined time interval, thereafter the blocking is released and the driver can move the shifter to a forward driving shifting position. In other embodiments, a sensor is provided which senses the force exerted by the driver on the shifter, wherein the control unit is arranged to release blocking of the shifter if the force on the shifter exceeds a threshold value. In a further alternative embodiment an override button is provided, and the control unit 20 is arranged to cease blocking of the shifter if the override button is pressed by the driver or an accepted voice command is given (see step 117) .

In step 106 the control unit 20 takes additional steps to pro^¬ vide the driver with further feedback, besides the blocking of the shifter preventing movement to a forward driving shift po^¬ sition, by altering the shift menu display so that allowed and blocked shift positions are displayed with their symbols in a different manner. Examples for such shift menu displays for the situation when an object has been detected in front of the vehicle are shown in Fig. 6A for an automatic transmission. In this example the shift menu display includes in its default state a linear sequence (although any configuration is possible) of shift positions indicated by the symbols D, P, N, and R. In the first example shown on the left hand side in Fig. 6A, the display of the symbol D is completely suppressed so that it is not visible in the situation when an object is de^¬ tected in front of the vehicle. In the next example in the middle of Fig. 6A the unsafe shift position D is displayed in a faded manner compared to the remaining shifting position symbols. In the next example on the right hand side of Fig. 6A the unsafe shifting position symbol D is displayed with a warning attribute, for example flashing or in a warning color such as red, which is indicated by the double brackets in the illustration .

Fig. 6B shows examples how the control unit 20 can alter the shift menu display for a manually shifted transmission in case an object has been detected in front of the vehicle. On the left hand side of Fig. 6B, the unsafe shifting positions for the forward driving gears are completely suppressed in the display so that only the reverse gear symbol remains visible. In the middle of Fig. 6B the unsafe forward driving shift po^¬ sitions are shown in a faded manner compared to the allowed reverse gear. In the example on the right hand side the shift menu display is altered such that the unsafe forward driving gear symbols are displayed with a warning attribute, for exam^¬ ple flashing or in a warning color such as red, which is indicated by the double brackets for the forward driving gears in Fig. 6B on the right hand side. After it is determined in step 105, by control unit 20, wheth^¬ er there is no detection of an obstacle in front of the vehi^¬ cle only, it is determined (step 107) whether an obstacle has only been detected behind the vehicle. If so, control unit 20 continues to step 108 and activates the magneto-rheological braking mechanism to block movement of the shifter to the rearward driving shift position. Again, this blocking is preferably overridable by the driver as has been described above in connection with the blocking of the shifter to a forward drive position in step 106. In this situation the control unit further alters the shift menu display to provide the driver with further feedback that the rearward drive shift position has been blocked. In the first example on the left hand side in Fig. 7A, the symbol R has been completely suppressed, in the example in the middle the symbol R is displayed in a faded manner, and in the example on the right hand side the symbol R is displayed with a warning attribute (indicated by the double brackets) which can be for example a flashing of the symbol or its display in a warding color such as red.

In Fig. 7B, the altered shift menu displays for a manually shifted transmission are shown for the case where an obstacle has been detected behind the vehicle only. In an analogous manner as in Fig. 7A, the unsafe rearward shift position symbol has been completely suppressed in the shift menu display in the example on the left hand side so that only the forward gears are displayed. In the example in the middle of Fig. 7B, the unsafe shift position R is shown in a faded manner, and in the example on the right hand side, the unsafe shift position symbol R is shown with a warning attribute such as flashing or in a warning color such is red.

Referring back to Fig. 4 again, it can be seen that if in step 107 it is found that the obstacle detection is not limited to - li ^¬

the area behind the car, it is confirmed in step 109 that ob^¬ stacles are detected in front of and behind the vehicle. In this case, the control unit 20, in step 110, activates the magneto-rheological braking mechanism to block movement of the shifter to the rearward shift position as well as to the for^¬ ward drive position (s) . Again, as described above for the sit^¬ uations with an obstacle in front of the car only or behind the car only, respectively, this blocking of the shifter by the braking/locking mechanism is preferably overridable by the driver .

In the same manner as described before for the situations with obstacles in front of or behind the vehicle only, control unit 20 alters the shift menu display in order to further alert the driver of the unsafe shift positions that have been blocked. Examples of altered shift menu displays for an automatic transmission are shown in Fig. 8A. Again, there are three examples in which the unsafe driving shift positions are shown with altered symbols (completely suppressed on the left hand side, faded symbols in the middle and symbols with warning at^¬ tributes (flashing or warning colors such is red) on the right hand side) . In Fig. 8B the altered shift menu display symbols are shown for an example of a manually shifted transmission.

In step 111, the control unit 20 determines whether a parking brake is applied. If not, no modification of the display of the shift menu is carried out If the parking brake is found to be engaged, control unit 20 performs the steps indicated in step 112 in Fig. 5. This means that control unit 20 activates the magneto-rheological braking mechanism, or other alterna^¬ tive locking/breaking mechanism, to block movement of the shifter to a forward driving shift position and to the rearward driving shift position. In addition, the shift menu display is altered to give visual feedback on the blocked shift^¬ ing positions. The resulting shift menu displays are the same as in Figs. 8A and 8B for the case of obstacles in front of as well as behind the vehicle.

If it is found in step 111 that the parking brake is not en^¬ gaged, no further steps are taken, i.e. the potential blocking of the shifter initiated before and any alteration of the shift menu display remains unmodified in step 113.

If it is found in step 114 that the driver selected a safe (unblocked) shift position, for example a forward drive shift position if no obstacle has been detected in front of the ve^¬ hicle, the unlimited or default shifter menu is restored after a predetermined time, i.e. any altered symbols, for example for R, in case an object had been detected behind the vehicle, before are restored to their normal form again (step 115) .

If it is found in step 114 that an unsafe or unacceptable shift position is intended to be selected, any possible block^¬ ing of the shifter is maintained in step 116 and corresponding shift menu displays are maintained with alterations for the shift symbols for the blocked shift positions. In addition, further warnings can be activated by the control unit 20, such as acoustic or haptic or visual warning feedback, as indicated in step 116 in Fig. 5. However, as indicated in step 117, in Fig. 5, the blocking of the shifter to unsafe shift positions is preferably overridable by the driver as described above. For example, the blocking can be released after a predetermined time period, or can be released if the driver exerts a force on the shifter above a threshold value, or if the driver actuates an override button or an accepted voice command is given to override the blocking of the shifter, thereafter the shifter can be operated to the shift positions selected by the driver and the shift menu display is returned to its normal or default state.

Claims

1. Shifter assembly for shifting a vehicle transmission having a rearward drive state and at least one forward drive state, said shifter assembly comprising: a shifter (21) moveable between a plurality of shift posi^¬ tions including a rearward driving position (R) and at least one forward driving position (D; 1, 2, 3, 4, 5, 6) corresponding to the rearward drive state and the at least one forward drive state, respectively, of the vehicle transmission; a control unit (20) arranged to be connectable to a sur^¬ roundings monitoring system (14, 16, 18) capable of de^¬ tecting obstacles in front of and behind the vehicle, wherein the control unit (20) is arranged to prevent shifting of the vehicle transmission to the rearward drive state if an obstacle behind the vehicle is detected, and to prevent shifting of the vehicle transmission to one of the at least one forward drive states if an obstacle in front of the vehicle is detected; characterized in that a mechanical locking mechanism or an adaptive braking mechanism (10, 12, 46) for blocking movement of the shifter (21) from a current to a new shift po^¬ sition is provided, and in that said preventing of shift^¬ ing of the vehicle transmission state is performed by the control unit (20) which is arranged to operate the mechan^¬ ical locking mechanism or the adaptive braking mechanism

(10, 12, 46) to block movement of the shifter (21) to the rearward driving position (R) if an obstacle behind the vehicle is detected, and to block movement of the shifter

(21) to the at least one forward driving position (D; 1, 2, 3, 4, 5, 6) if an obstacle in front of the vehicle is detected by the surroundings monitoring system.

2. Shifter assembly according to claim 1, characterized in that the control unit (20) is arranged, if an obstacle has been detected, and operating of the shifter (21) to an intended driving position is blocked, to allow the driver to override blocking of the shifter by releasing the mechanical locking mechanism or the adaptive braking mechanism (i) after predetermined period of time expired, or (ii) if the force exerted on the shifter (21) towards the intended driving position exceeds a threshold value, (iii) if an override button is pressed by the driver, or (iv) an ac^¬ cepted voice command is given.

3. Shifter assembly according to claim 1 or 2, characterized in that the shifting positions of the shifter are indicat^¬ ed in a shifting menu display (22) presenting symbols for the shift positions which are available by operating the shifter to get to a shifting state which corresponds to one of the displayed symbols.

4. Shifter assembly according to claim 3, characterized in that and in that the control unit (20) is arranged, if an obstacle has been detected, and moving of the shifter to an intended shifting position is blocked because of the obstacle detected, to alter the shift menu display (22) of the symbols for the shift positions to which movement of the shifter has been blocked by fading such driving position symbols, by turning off the display of such that such symbols become invisible or by altering the symbols or their background to include a warning attribute such as fading, flashing or a warning color.

5. Shifter assembly according to claim 3 or 4, characterized in that the control unit (20) is arranged, if an obstacle has been detected and moving of the shifter to an intended shifting position is blocked because of the obstacle de^¬ tected, to alter the shift menu display (22) of the sym^¬ bols for the shift positions to which movement of the shifter has not been blocked by displaying such symbols or their background in a color indicating a safety confirma^¬ tion, such as in green color.

6. Shifter assembly according to any of claims 3 to 5, char^¬ acterized in that the control unit (20) is arranged to de^¬ termine whether a parking brake is applied, and if so to activate the mechanical locking mechanism or the adaptive brake mechanism (10, 12, 46) to block movement of the shifter (21) to the rearward (R) and forward driving posi^¬ tions (D; 1, 2, 3, 4, 5, 6) and to alter the displays of the symbols these driving positions by turning off the display of these such that such symbols become invisible, or by altering the symbols or their background to include a warning attribute such as fading, flashing or a warning color .

7. Shifter assembly according to any preceding claim, characterized in that an acoustic warning signal generator is provided, and in that the control unit (20) is arranged, if an obstacle has been detected and moving of the shifter to a shifting position having a driving direction corresponding to the direction of the detected obstacle is blocked, to activate the acoustic warning signal generator to produce an acoustic warning signal.

8. Shifter assembly according to any preceding claim, characterized in that a surroundings monitoring system (14, 16, 18) is arranged to be able to detect stationary and moving obstacles and is arranged to predict the position of mov^¬ ing obstacles, wherein the surroundings monitoring system is arranged to signal presence of an obstacle in front of and/or behind the vehicle if the predicted position of the moving obstacle (s), whether initially to the side, front or rear of the vehicle, after a predetermined delay time would be in the driving path of the vehicle, either in front of and/or behind the vehicle.