GB2540464A

GB2540464A - Controller

Info

Publication number: GB2540464A
Application number: GB1609379.1A
Authority: GB
Inventors: Krehl Claudia; Hasedzic Elvir; Singh Harpreet; Shinu Peter
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2015-06-01
Filing date: 2016-05-27
Publication date: 2017-01-18
Anticipated expiration: 2036-05-27
Also published as: GB201509430D0; GB201609379D0; GB2540464B

Abstract

The present disclosure relates to a controller e.g. speed control system, for a vehicle (Fig.1, 10). The controller comprises an input for receiving a target speed demand, from a target speed input 38, 40, and a current speed, sensed from a speed sensor 32. The controller also comprises a control module 44 arranged to generate a resistance force or haptic feedback in response to the current speed exceeding the target speed. In addition, the controller comprises an output 46 arranged to output a resistance command to a mechanism for applying the resistance force to an accelerator or gas pedal (Fig.2, 18). The resistance force may be sufficient to allow the pedal to act as a footrest. The driver may input the target speed manually or the speed may be automatically input based on traffic signs, navigation data or obstacles within a three-dimensional mapped environment around the vehicle.

Description

CONTROLLER

TECHNICAL FIELD

The present disclosure relates to a controller and particularly, but not exclusively, to a speed limiter for a land vehicle. Aspects of the invention relate to a controller, a speed control system, and a vehicle and a method of providing feedback to a driver.

BACKGROUND A vehicle, such as a car, includes a drive system for driving the vehicle. The drive system includes an accelerator pedal linked, either mechanically or as part of a drive-by-wire system, to an engine. The position of the accelerator pedal configures the engine to output an engine torque, which engine torque is transfer along a drive train to a set of wheels for moving the car.

Oftentimes, cars include a speed control system, or otherwise called a cruise control system. A typical speed control system monitors a current speed of the car and allows a user to manually input a desired target speed. The target speed can be input using pushbuttons on the steering wheel or using a dashboard mounted electronic human interface. Typical speed control systems work by configuring the engine and/or a braking system of the vehicle to maintain a speed equal to the target speed. Once the target speed has been set, the driver may remove their foot from the accelerator pedal since the position of the accelerator pedal is no longer required to control the engine.

However, such speed control systems are not ideal since a foot well in a car is often not ideally shaped to provide alternative foot positions to the pedals. Accordingly, foot slips resulting in the accelerator pedal being accidentally pressed often occur which may inadvertently increase the car speed past the target speed and/or waste fuel by temporarily over-revving the engine.

It is an aim of the present invention to address disadvantages associated with the prior art. SUMMARY OF THE INVENTION

Aspects and embodiments of the invention provide a controller, a speed control system, a vehicle and a method of providing driver feedback as claimed in the appended claims.

According to an aspect of the present invention there is provided a controller for a vehicle. The controller may comprise an input for receiving a target speed demand, from a target speed input, and a current speed, sensed from a speed sensor. The controller may comprise a control module arranged to generate a resistance force in response to the current speed exceeding the target speed. The controller may comprise an output arranged to output a resistance command to a mechanism for applying the resistance force to an accelerator pedal.

Without limitation, the current speed may be a current vehicle speed.

For the avoidance of doubt, the term “accelerator pedal” as used herein, including in the claims, is not intended to be limiting and may be interpreted to include other devices which are commonly used to request acceleration of the vehicle including, but not limited to, a handlebar-type accelerator control or a throttle lever-type accelerator control. Applying resistance to the accelerator pedal acts as a measure of haptic feedback. This feedback advises the driver that no further acceleration is required. The resistance applied to the accelerator pedal also minimizes the risk that a driver will slip and inadvertently press the accelerator pedal. In turn, there is a reduced risk of over revving the engine and wasting fuel.

In an embodiment, the resistance force is sufficient for the accelerator pedal to act as a footrest. In this way, the driver need not remove their foot from the pedal when the target speed has been reached. This is more comfortable for the driver and allows a greater degree of flexibility in the layout of the foot well. In addition, if the driver needs to depress the accelerator pedal subsequently, there is no need to reposition the foot. In this way, the response time of the driver to input further acceleration is reduced.

In an embodiment, the resistance force is applied at a pedal position associated with the target speed. In this way, the driver has a degree of additional feedback as to the target speed due to previous knowledge of accelerator positions associated with various speeds.

In an embodiment, the controller is arranged to reduce the resistance force in response to the accelerator pedal being depressed past a position associated with the target speed. Allowing the resistance force to be overcome by the driver and reducing the resistance force in such an event allows the driver to manually input an accelerator demand should there be need for doing so.

The controller may be arranged to maintain the target speed when the accelerator pedal is depressed past the position associated with the target speed. This has the advantage of allowing the driver to manually input an accelerator demand without affecting the target speed.

The controller may be arranged to return the accelerator pedal to the position associated with the target speed following removal of force applied to the accelerator pedal to depress the accelerator pedal past a position associated with the target speed. This has the advantage of maintaining feedback to the driver regarding the target speed due to the driver’s previous knowledge of accelerator positions associated with various speeds.

In a further aspect of the present invention there is provided a vehicle speed control system comprising; an accelerator pedal, a target speed input, a speed sensor, and the aforementioned controller.

Without limitation the speed sensor may comprise a vehicle speed sensor such as a tachometer arranged to determine the speed of the vehicle from the rotational speed of the vehicle wheels.

In an embodiment, the vehicle speed control system comprises an activator for activating and/or deactivating the controller. In this way, the driver can have more control over the implementation of the system and select when the system should or shouldn’t be used.

In an embodiment, the target speed input is a manual target speed input for a driver to manually input the target speed.

In an embodiment, the target speed input is an automatic target speed input for automatically detecting the target speed. In this way, the system will work independently of the driver having any knowledge of upcoming speed limits.

In an embodiment, the automatic target speed input comprises a traffic sign recognition system arranged to observe a traffic sign using a camera and determine the target input based on the observed traffic sign. Traffic signs are plentiful in most developed countries and so such a technique is a reliable way in which to determine the target speed limit.

In an embodiment, the target speed input comprises a navigation system, said navigation system comprising a means for determining a current position of the vehicle and a means for determining a plurality of speed limits located relative to the current position of the vehicle.

Similarly to the traffic sign recognition system, navigation systems are reliable and robust technologies allowing for reliable speed limit determination.

In an embodiment, the automatic target speed input comprises an environment monitoring system comprising a three dimensional mapping tool for mapping a three dimensional environment surrounding the vehicle, the environment monitoring system arranged to recognise an object in the mapped environment and associate a target speed with the recognised object.

By objects we mean various obstacles which a vehicle may encounter, such as a gradient, a road surface type, a turn in the road, and any upcoming obstacles such as rocks. Taking in account such objects provides a more reliable system.

According to a further aspect of the present invention there is provided a vehicle comprising the aforementioned speed control system.

According to a further aspect of the present invention there is provided a method of providing driver feedback in a vehicle. The method may comprise receiving a target speed demand, from a target speed input, and a current speed sensed from a speed sensor. The method may comprise generating haptic feedback in response to the current speed exceeding the target speed. The method may comprise applying the haptic feedback to an accelerator pedal of the vehicle.

Without limitation, the current speed may be a current vehicle speed.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a vehicle including a speed control system according to an embodiment of the present invention;

Figure 2 shows an accelerator pedal from the vehicle of Figure 1;

Figure 3 shows a block diagram of the speed control system of Figure 1;

Figure 4 shows a flow diagram of the speed control system of Figure 3 in operation; and Figure 5 shows a flow diagram of an output from the speed control system of Figure 3. DETAILED DESCRIPTION

With reference to Figure 1, a vehicle 10 includes a body 12 and a set of wheels 14 for driving the vehicle 10. The vehicle also includes a stereoscopic camera 16, the reasons for which will be described below.

With reference to Figure 2, the vehicle also includes an accelerator pedal 18. The accelerator pedal is pivotably mounted by a pivot 20 at an upper end so as to be inclined from a foot well 22. A mechanism in the form of an actuator 24, or a motor, is provided, which actuator is connected at a cylinder end 26 to the foot well 22 and at a piston end 28 to a lower end of the pedal 18. The actuator 24 is extendable and retractable longitudinally to apply a resistive force to the pedal 18 and to determine the pedal position, respectively. In-use the accelerator pedal 18 position is arranged to configure the engine to output an engine torque for ultimately controlling the speed of the wheels 14 (Figure 1).

With reference to Figure 3, the vehicle also includes a speed control system 30. The speed control system 30 includes a speed sensor 32, an activator in the form of an automatic activator 34 and a manual activator 36, inputs for receiving a target speed demand, which inputs include a manual target speed input 38 and an automatic speed input 40, an accelerator pedal input 42, a control module 44, and an output 46. The control module 44 and the output 46 form the basis of a controller of the speed control system 30.

The speed sensor 32 is a tachometer arranged to determine the speed of the vehicle by the rotational speed of the wheels 14 (Figure 1). The speed sensor 32 is linked to the control module 44 to act as an input for monitoring a current vehicle speed.

The automatic activator 34 is a vehicle system arranged to allow or reject the use of the speed control system 30 depending on other factors such as other types of haptic feedback (described later) which may be implemented by other systems of the vehicle.

The manual activator 36 is a switch for allowing a driver to manually activate or de-active the controller. The manual activator 36 can take various forms, such as a dashboard mounted electromechanical switch or as an input to a human machine interface in the form of a touch screen. Both activators are linked to the control module 44 for selectively activating and deactivating the controller.

The manual target speed input 38 and the automatic target speed input 40 are again linked to the control module 44 to act as inputs for inputting a target speed for the vehicle to travel at. The manual target speed input 38 is again in the form of an input to a human machine interface in the form of a touch screen, which touch screen may be dashboard mounted. The target speed can be input from a drop down menu or entered manually using an alphanumeric soft keypad. The automatic target speed input 40 may take various forms. However the function of the input 40 is to detect automatically the target speed for the vehicle such that the driver need not intervene.

The automatic target speed input 40 may be in the form of a traffic sign recognition system, a navigation system, or an environment monitoring system.

The traffic sign recognition works using the camera 16 to observe upcoming objects, including road signs. The images are processed and compared to a database of stored images, such as the shape of road signs, e.g. a triangular or a circular shape, as well as text or patterns, for instance 30, signifying 30 mph (or kph). Upon recognising the image, a target speed is generated to match the speed associated with the road sign. The target speed then sent to the control module 44.

The navigation system includes an electronic map, or e-map, and a Global Positioning System (GPS). The e-map has information relating to road routes and associated speed limits of those road routes. In this way, the navigation system can determine the current speed limit of the vehicle and also any upcoming changes in speed limits according to the proximity of the vehicle on the e-map. For instance a current speed of 60 mph will result in the target speed being registered as 60 mph. The upcoming speed limit will be input to the control module as a ‘target speed limit’. The distance of travel to the point of change of speed limit will also be sent as part of the target speed limit signal.

The environment monitoring system works by using a radar in place of the camera 16. A radar signal is sent to scan the environment surrounding the vehicle. A three dimensional map of the surrounding environment is created based on reflections from the radar signal. The environment monitoring system also has a database of objects, such as road gradient changes, road bends, upcoming round-a-bouts, etc. Any objects detected in the environment are associated with a manoeuvring speed. In this case, the manoeuvring speed is the target speed. The distance to the target speed is also detected by the system. Both the target speed and the distance thereto are sent to the control module 44. For instance, an upcoming roundabout may be associated with a speed limit of 25mph. Accordingly, the target speed of 25 mph is sent to the control module.

The accelerator pedal input 42 is arranged to monitor the position of the actuator 24 and also the force applied to the actuator in pressing the pedal. This input 42 is sent to the control module 44 in addition to a control module (not shown) for configuring an engine control system (ECS) for controlling an engine torque.

The control module 44 is arranged to monitor the current speed of the vehicle and the target speed. When the current speed exceeds the target speed, the control module 44 recognises that any further acceleration demand input to the accelerator pedal will cause the current speed to exceed further the target speed. For instance, a current vehicle speed of 30mph, exceeds a target speed of 20mph, as read from a road sign for instance. The control module 44 will generate a resistance force 48 to be applied to the accelerator pedal 18 for preventing further depression of the pedal 18. The force may be applied at a particular point of travel of the pedal 18 to allow movement up to a position associated with the target speed but resist any additional movement. A user may in fact use the resisted pedal as a footrest since the force is sufficient to act as such.

In particular a force arranged to apply a moment to the accelerator pedal of between 8 and 14Nm will suffice for the pedal to act as a footrest. More specifically, a moment of 11Nm would be most likely.

However, in the event of a sudden need for an injection of acceleration, the resistance force may be overcome by a larger opposing force exerted on the pedal by the driver. In such an event, the control module 44 reconfigures the actuator 24 so as to apply a lower magnitude force to allow the driver to manually drive the vehicle in the time of need. Such a case may arise where acceleration is required to avoid a potential collision such as in the event of overtaking a slow moving vehicle on a single carriageway.

Figure 4 shows this functionality of the control module 44 in the form of a flow chart. With reference to both Figures 3 and 4, initially the control module 44 is off as shown at step 50. The control module 44 is then activated, or turned on, at step 52 by the automatic or manual activators. The control module 44 will send an update to the dashboard mounted human machine interface to advise that the feature, or control module 44, is on. At step 53, the driver manually sets the target speed using the manual activator 36 (Figure 3). Of course, step 53 is applicable to the alternative case whereby the automatic activator 34 automatically detects the target speed. Step 54 represents the driver driving in a normal manual way using the accelerator pedal to control the engine torque and ultimately the speed of the vehicle, subject to gear box setting.

When the target speed is less than or equal to the current speed, the control module will generate a resistive force to be sent via the output to the actuator to apply the resistive force to the pedal, as shown at step 56. In this way, the pedal 18 (Figure 2) may be used as a footrest until the feature is deactivated.

The pedal position, or torque demand, is constantly monitored as per step 57. At step 58, when the target speed is exceeded, the pedal 18 will remain resistive even if a driver applies a force to the accelerator pedal which is lower than the resistive force already being applied. However, as per step 60, when the driver applies an opposing force greater than the resistive force, the control module modifies the resistance force to a lesser amount to allow the driver to manually accelerate in times of need.

In an embodiment, even though the driver has applied an opposing force to the accelerator pedal 18 greater than the resistive force, such that the resistive force is reduced to a lesser amount to allow the driver to manually accelerate, the target speed remains unaffected.

In some embodiments, the accelerator pedal is biased to return to the position associated with the target speed. Therefore, when the driver reduces or removes the opposing force applied to the accelerator pedal 18, the accelerator pedal travels towards the position associated with the target speed. In some embodiments, the resistive force is arranged to subsequently increase to its original value, that is, to the value that was present before the accelerator pedal 18 was depressed past a position associated with the target speed. The driver is then aware of the target speed from the position of the accelerator pedal 18. The accelerator pedal 18 can again act as a footrest, since the resistive force is reinstated.

With reference to Figure 5, the output is shown in the form of a flow diagram. In particular, step 62 shows the fact that the torque demand, or pedal position, is greater than required for the target speed. The speed limit at step 64 is thus limited by applying the force at step 66 to the pedal, which force is shown graphically as a step change in resistance force at step 68.

Claims

1. A controller for a vehicle, the controller comprising; an input for receiving a target speed demand, from a target speed input, and a current speed, from a speed sensor; a control module arranged to generate a resistance force in response to the current speed exceeding the target speed; and an output arranged to output a resistance command to a mechanism for applying the resistance force to an accelerator pedal.

2. The controller of claim 1 wherein the resistance force is sufficient for the accelerator pedal to act as a footrest.

3. The controller of claim 1 or claim 2 wherein the resistance force is applied at a pedal position associated with the target speed.

4. The controller of any of claims 1 to 3 wherein the control module is arranged to reduce the resistance force in response to the accelerator pedal being depressed past a position associated with the target speed.

5. The controller of claim 4, wherein the control module is arranged to maintain the target speed when the accelerator pedal is depressed past the position associated with the target speed

6. A vehicle speed control system comprising; an accelerator pedal, a target speed input, a speed sensor, and the controller of any preceding claim.

7. The vehicle speed control system of claim 6 comprising an activator for activating and/or deactivating the controller.

8. The vehicle speed control system of claim 6 or claim 7 wherein the target speed input is a manual target speed input for a driver to manually input the target speed.

9. The vehicle speed control system of claim 6 or claim 7 wherein the target speed input is an automatic target speed input for automatically detecting the target speed.

10. The vehicle speed control system of claim 9 wherein the automatic target speed input comprises a traffic sign recognition system arranged to observe a traffic sign using a camera and determine the target input based on the observed traffic sign.

11. The vehicle speed control system of claim 9 or claim 10 wherein the automatic target speed input comprises a navigation system, said navigation system comprising a means for determining a current position of the vehicle and means for determining a plurality of speed limits located relative to the current position of the vehicle.

12. The vehicle speed control system of any of claims 9 to 11 wherein the automatic target speed input comprises an environment monitoring system comprising a three dimensional mapping tool for mapping a three dimensional environment surrounding the vehicle, the environment monitoring system arranged to recognise an object in the mapped three dimensional environment and associate a target speed with the recognised object.

13. A vehicle comprising the speed control system of any of claims 6 to 12.

14. A method of providing driver feedback in a vehicle comprising; receiving a target speed demand, from a target speed input, and a current speed sensed from a speed sensor; generating haptic feedback in response to the current speed exceeding the target speed; and applying the haptic feedback to an accelerator pedal of the vehicle.

15. A controller, a speed control system, a vehicle or a method of providing driver feedback as substantially described herein with reference to the accompanying figures.