Patent Publication Number: US-2022221882-A1

Title: Controlling movement of a vehicle

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/481,326, filed on Aug. 26, 2019, which is the national stage application of International Application No. PCT/EP2018/051320, filed Jan. 19, 2018, which claims priority to United Kingdom Application No. GB 1701443.2, filed Jan. 30, 2017. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to controlling movement of a vehicle. In particular, but not exclusively it relates to controlling movement of a road vehicle such as a car. 
     Aspects of the invention relate to an apparatus, a system, a vehicle, a method and a computer program. 
     BACKGROUND 
     Providing a road vehicle with means for enabling it to be moved by remote control using a mobile phone application has been proposed. One problem with such an arrangement is how to maximize the safety of the vehicle and people within the vicinity of the vehicle, including the vehicle operator, while the vehicle is being remotely controlled. 
     It is an aim of the present invention to address this problem. 
     SUMMARY OF THE INVENTION 
     Aspects and embodiments of the invention provide an apparatus, a system, a vehicle, a method and a computer program as claimed in the appended claims. 
     According to an aspect of the invention there is provided an apparatus for controlling movement of a vehicle, the apparatus comprising processing means that, in a remote control mode, is configured to: receive a first signal from a receiving means in dependence on a transmitted signal received from a remote control device indicating a requested motion of a vehicle; receive a further signal from a key detection means configured to receive a key signal from a smart key for the vehicle; determine, from the first signal or from an additional signal received from a sensing means, one or more distance values, the or each distance value being indicative of a distance from a point on the vehicle to an object; determine a maximum speed value for the vehicle in dependence on at least one of the one or more distance values and on the further signal being indicative of a smart key being detected; and provide an output signal for controlling speed of the vehicle based on the requested motion, wherein the output signal is arranged to control the speed of the vehicle to be less than or equal to the maximum speed value. 
     The apparatus may be an electronic control unit (ECU). The output signal may be for providing to a powertrain and/or a brake mechanism of the vehicle to control its speed. 
     This provides the advantage that the speed of the vehicle may be limited in dependence on the distance from the vehicle to nearby obstacles, such as an inanimate object or the person controlling the vehicle using the remote control device. This enables the speed to be restricted to a relatively slow speed when the distance to obstacles is relatively small, and so the likelihood of the vehicle being safely moved by remote control is increased. 
     According to another aspect of the invention there is provided an apparatus for controlling movement of a vehicle, the apparatus comprising processing means configured to: receive first signals from a receiving means arranged to receive transmitted signals from a remote control device indicating a requested motion of a vehicle; determine a distance value from the first signals indicative of a distance from an aerial on the vehicle to the remote control device; 
     determine a maximum speed value for the vehicle in dependence on the distance value; and 
     provide an output signal for controlling speed of the vehicle based on the requested motion, wherein the output signal is limited dependent upon the maximum speed value. 
     This provides the advantage that the speed of the vehicle may be limited in dependence on the distance from the vehicle to the person controlling the vehicle using the remote control device, so that the vehicle may be made to move relatively slowly when the distance is relatively small and allowed to move relatively quickly when the distance is relatively larger. In this way, the safety of the person controlling the vehicle may be increased. 
     According to another aspect of the invention there is provided an apparatus for controlling movement of a vehicle, the apparatus comprising processing means configured to: receive first signals indicative of a signal strength of received transmitted signals from a remote control device indicating a requested motion of a vehicle; determine a maximum speed value for the vehicle in dependence on the first signals; and provide an output signal for controlling speed of the vehicle based on the requested motion, wherein the output signal is limited dependent upon the maximum speed value. 
     This provides the advantage of enabling the speed of the vehicle to be limited to a relatively slow speed when the signal strength is very high indicating that the remote control device is very close to the vehicle and enabling the speed of the vehicle to be limited to a relatively higher speed when the signal strength is lower indicating that the remote control device is a safe distance from the vehicle. It also enables the vehicle to be limited to a relatively slow speed when the signal strength is very low indicating that the remote control device approaching a distance at which the communication between the remote control device and the vehicle may become unreliable. 
     According to another aspect of the invention there is provided an apparatus for controlling movement of a vehicle, the apparatus comprising processing means configured to: receive data included within signals transmitted from a remote control device indicating a requested motion of a vehicle; receive an additional signal from a sensing means indicative of a distance from a point on the vehicle to an obstacle; determine a maximum speed value for the vehicle in dependence on the additional signal; and provide an output signal for controlling speed of the vehicle based on the requested motion, wherein the output signal is limited dependent upon the maximum speed value. 
     This provides the advantage that the speed of the vehicle may be limited in dependence on the distance from the vehicle to nearby obstacles, such as an inanimate object or the person, detected by the sensing means. 
     According to another aspect of the invention there is provided an apparatus for controlling movement of a vehicle, the apparatus comprising an electronic memory device having instructions stored therein and an electronic processor configured to access the electronic memory device and execute the instructions stored therein such that it is operable to: receive first signals from a radio unit arranged to receive transmitted signals from a remote control device indicating a requested motion of a vehicle; determine, from the first signals or at least one additional signal received from at least one sensor, a distance value indicative of a distance from a point on the vehicle to an obstacle; determine a maximum speed value for the vehicle in dependence on the distance value; and provide an output signal for controlling speed of the vehicle based on the requested motion, wherein the output signal is limited dependent upon the maximum speed value. 
     In some embodiments the first signals provide an indication of signal strength of the received transmitted signals. This provides the advantage that the processing means is able to determine a distance from a remote control device to a receiving means located on the vehicle from the signal strength indication. 
     In some embodiments the processing means is configured to determine the one or more distance values from the first signals. This provides the advantage that the speed of the vehicle may be limited in dependence on the distance from the vehicle to the person controlling the vehicle using the remote control device. 
     In some embodiments the processing means is configured to determine the one or more distance values from an additional signal received from a sensing means. This provides the advantage that the speed of the vehicle may be limited in dependence on the distance from the vehicle to any nearby objects, such as an inanimate objects or people, that are detectable by the sensing means and which may present an obstacle to movement of the vehicle. 
     In some embodiments the processing means is configured to: determine a first distance value from the first signals and a second distance value from the additional signal received from the sensing means; and determine the maximum speed value in dependence on the first distance value or the second distance value. The processing means may be configured to: compare the first distance value and the second distance value to determine which is smallest; and determine the maximum speed value in dependence on the smallest one of the first distance value and the second distance value. 
     The processing means may be configured to: determine a first speed value from the first distance value; determine a second speed value from the second distance value; and determine the maximum speed value as the lower one of the first speed value and the second speed value. This provides the advantage that a safe speed limit may be calculated in regard to the distance to the remote control device held by the person controlling the vehicle and a second safe speed limit with regard to the distance to the nearest object detected by the sensing means, and the vehicle may be limited to the least of these two speeds to assist safe movement of the vehicle. 
     In some embodiments the processing means is configured to: receive a plurality of additional signals, each additional signal being received from a respective one of a plurality of sensors; and perform a process of sensor fusion to obtain the, or each, distance value. This provides the advantage of basing the maximum speed value on a more accurate distance value than would be obtained from an individual sensor. 
     In some embodiments the transmitted signal comprises information indicating at least one of: a requested speed of the vehicle, a request to apply brakes of the vehicle, a requested steering angle, a requested direction of travel, a requested gear selection and a requested amount of power provided by a powertrain of the vehicle. 
     In some embodiments the processing means is configured to determine from the first signal a distance value indicative of the distance from the point on the vehicle to the remote control device. 
     In some embodiments the sensing means comprises one or more of a camera, an ultrasonic proximity sensor and an electromagnetic proximity sensor. This provides the advantage that electronic sensors present within the vehicle for other purposes, such as assisting parking, may be used to limit the speed of the vehicle when being remotely controlled. 
     Determining a maximum speed value in dependence on the further signal being indicative of a smart key being detected provides the advantage of providing a well-defined zone around the vehicle in which the speed of the vehicle can be kept below a relatively low maximum speed when the person in possession of the key is within the zone. 
     In the remote control mode, the processing means may be configured to provide an output signal to cause the vehicle to be stationary in dependence on the further signal being indicative of the smart key being within the vehicle. 
     In some embodiments the processing means is configured to compare a signal strength of the transmitted signal with at least one threshold value and to determine a distance value in dependence thereon. 
     In some embodiments the processing means is configured to: compare a signal strength of the transmitted signal to a first threshold value and a second threshold value; and produce a first maximum speed value in dependence on the signal strength of the transmitted signal being determined to be above the first threshold value and produce a second maximum speed value in dependence on the signal strength of the transmitted signal being determined to be below the first threshold value and above the second threshold value, and wherein the first maximum speed value is less than the second maximum speed value. 
     The processing means may be configured to produce a third maximum speed value in dependence on the signal strength of the transmitted signal being determined to be below the second threshold value, and wherein the third maximum speed value is below the second maximum speed value. 
     The processing means may be configured to compare signal strength of the transmitted signals to a third threshold value and cause the vehicle to stop in dependence on the signal strength of a transmitted signal being below the third threshold value. This provides the advantage that the vehicle is safely brought to a standstill before the communication between the remote control device and the vehicle become unreliable due to the signal becoming too weak. 
     In some embodiments the processing means comprises an electronic processor communicatively coupled to an electronic memory device having instructions stored therein and the electronic processor having an electrical input for receiving the first signal; and the sensing means comprises at least one electronic sensor for providing a signal indicative of a distance to an object. 
     According to another aspect of the invention there is provided a system for controlling the movement of a vehicle comprising the apparatus according to any one of the previous paragraphs, a receiving means for receiving the transmitted signals from a remote control device via a wireless local area network. 
     In an embodiment, the receiving means includes a signal strength monitor arranged to perform a measurement of power of signals received from a remote control device and generate the first signals in dependence on the measurement. 
     According to another aspect of the invention there is provided a vehicle comprising an apparatus or a system as described above, wherein the speed of the vehicle is limited to a speed dependent on the maximum speed value determined from the distance value. 
     According to another aspect of the invention there is provided a method of controlling movement of a vehicle, the method comprising: receiving a first signal from a receiving means in dependence on transmitted signal from a remote control device indicating a requested motion of a vehicle; receiving further signals from a key detection means configured to receive signals from a smart key of the vehicle; determining, from the first signal or an additional signal received from a sensing means, one or more distance values, the or each distance value being indicative of a distance from a point on the vehicle to an object; determining a maximum speed value for the vehicle in dependence on at least one of the one or more distance values and on the further signal being indicative of a smart key being detected; and providing an output signal for controlling speed of the vehicle based on the requested motion, wherein the output signal controls speed of the vehicle to be less than or equal to the maximum speed value. 
     This provides the advantage that the speed of the vehicle may be limited in dependence on the distance from the vehicle to nearby obstacles, such as an inanimate object or the person controlling the vehicle using the remote control device. 
     In an embodiment the determining a maximum speed value comprises: determining a first distance value from the first signal and a second distance value from an additional signal received from a sensing means; and determining the maximum speed value in dependence on the first distance value or the second distance value. 
     This provides the advantage that the distance from the vehicle to nearby obstacles, and the distance to the person controlling the vehicle using the remote control device may be taken into account when limiting the speed of the vehicle. 
     The determining the maximum speed value in dependence on the first distance value or the second distance value may comprise: determining a first speed value from the first distance value; determining a second speed value from the second distance value; and determining the maximum speed value as the lower one of the first speed value and the second speed value. This provides the advantage that a safe speed limit may be calculated in regard to the distance to the remote control device held by the person controlling the vehicle and a second safe speed limit with regard to the distance to the nearest object detected by the sensing means, and the vehicle may be limited to the least of these two speeds to assist safe movement of the vehicle. 
     In an embodiment the method comprises receiving a plurality of additional signals, each additional signal being received from a respective one of a plurality of sensors; and performing a process of sensor fusion to obtain the, or each, distance value. This provides the advantage of basing the maximum speed value on a more accurate distance value than would be obtained from an individual sensor. 
     In an embodiment the transmitted signals comprise information indicating at least one of: a requested speed of the vehicle, a request to apply brakes of the vehicle, a requested steering angle, a requested direction of travel, a requested gear selection and a requested amount of power provided by a powertrain of the vehicle and said providing an output signal comprises providing an output signal to at least one of a brakes mechanism and a powertrain, to cause the speed of the vehicle to be less than or equal to a speed corresponding to the maximum speed value. 
     Providing an output signal to cause the speed of the vehicle to be less than or equal to a first speed in dependence on the further signal being indicative of a smart key being detected provides the advantage of providing a well-defined zone around the vehicle in which the speed of the vehicle can be kept below a relatively low maximum speed when the person in possession of the key is within the zone. 
     According to a still further aspect of the invention there is provided a computer program that, when run on a processor, performs a method as described above. 
     According to a still further aspect of the invention there is provided a non-transitory computer readable medium comprising a computer program that, when run on a processor, performs a method as described above. 
     The apparatus may be for controlling the movement of a road vehicle such as a car. 
     In some, but not necessarily all, examples of by the present disclosure there is provided an apparatus for controlling movement of a vehicle, the apparatus comprising processing means that, in a remote control mode, is configured to: receive a first signal from a receiving means in dependence on a transmitted signal received from a remote control device indicating a requested motion of a vehicle; determine, from the first signal or from an additional signal received from a sensing means, one or more distance values, the or each distance value being indicative of a distance from a point on the vehicle to an object; determine a maximum speed value for the vehicle in dependence on at least one of the one or more distance values; and provide an output signal for controlling speed of the vehicle based on the requested motion, wherein the output signal is arranged to control the speed of the vehicle to be less than or equal to the maximum speed value. 
     A system for controlling the movement of a vehicle comprising this apparatus, a receiving means for receiving the transmitted signals from a remote control device via a wireless local area network is also disclosed. 
     A vehicle comprising one of these apparatus or system, wherein the speed of the vehicle is limited to a speed dependent on the maximum speed value determined from the distance value is also disclosed. 
     In some, but not necessarily all, examples of by the present disclosure there is provided a method of controlling movement of a vehicle, the method comprising: receiving a first signal from a receiving means in dependence on transmitted signal from a remote control device indicating a requested motion of a vehicle; determining, from the first signal or an additional signal received from a sensing means, one or more distance values, the or each distance value being indicative of a distance from a point on the vehicle to an object; determining a maximum speed value for the vehicle in dependence on the one or more distance values; and providing an output signal for controlling speed of the vehicle based on the requested motion, wherein the output signal controls speed of the vehicle to be less than or equal to the maximum speed value. 
     A computer program that, when run on a processor, performs this method is also disclosed. 
     A non-transitory computer readable medium comprising a computer program that, when run on a processor, performs this method is also disclosed. 
     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: 
         FIG. 1  shows a block diagram of an apparatus  101  for controlling the movement of a vehicle; 
         FIG. 2  shows a block diagram of a system  201  incorporating the apparatus  101  within a vehicle  202 ; 
         FIG. 3  shows a schematic plan view of the vehicle  202  and positions of the proximity sensors  210 , cameras  211  and key detectors  214 ; 
         FIG. 4A  shows a graph  401  illustrating how power of the received signal received at the radio unit  103  may decrease as distance separating the radio unit  103  and the remote control device  204  increases; 
         FIG. 4B  shows a graph  402  illustrating an example of how a maximum speed value may be selected in dependence upon the determined distance between the radio unit  103  and the remote control device  204 ; 
         FIG. 5  shows a flowchart of a method  500  of controlling the movement of a vehicle; 
         FIG. 6  shows a flowchart of a method  600  of controlling the movement of a vehicle; 
         FIG. 7  shows a flowchart of additional processes  701 ,  702  and  703  that may be incorporated into the method  500  of  FIG. 5  or the method  600  of  FIG. 6 ; 
         FIG. 8  shows a flowchart of an example of the process  602  of  FIG. 6  of determining the first distance value; 
         FIG. 9  shows an example of the process of block  603  of  FIG. 6 ; 
         FIG. 10  shows a flowchart of example processes that may be included in the process block  604  of  FIG. 6 ; 
         FIG. 11  shows an alternative system  1101  embodying the invention that differs from system  201  of  FIG. 2  in that the signal strength monitor  206  is omitted; 
         FIG. 12  shows a system  1201  embodying the present invention that differs from system  201  of  FIG. 2  in that it does not include the sensing means  104 ; and 
         FIG. 13  shows another alternative system  1301  embodying the present invention that differs from system  201  of  FIG. 2  in that it includes a global navigation satellite system (GNSS) module  1302 . 
     
    
    
     DETAILED DESCRIPTION 
     The Figures illustrate Apparatus  101  for controlling movement of a vehicle  202 , the apparatus  202  comprising processing means  102  that, in a remote control mode, is configured to: receive a first signal from a receiving means  103  in dependence on a transmitted signal received from a remote control device  204  indicating a requested motion of a vehicle  202 ; determine, from the first signal or from an additional signal received from a sensing means  104 , one or more distance values, the or each distance value being indicative of a distance from a point on the vehicle  202  to an object; determine a maximum speed value for the vehicle  202  in dependence on at least one of the one or more distance values; and provide an output signal  106  for controlling speed of the vehicle  202  based on the requested motion, wherein the output signal  106  is arranged to control the speed of the vehicle  202  to be less than or equal to the maximum speed value. 
     The maximum speed value may be a maximum speed to which the vehicle is limited by limiting the output signal, or may be indicative of such a maximum speed. Thus, the output signal is limited so that the controlled speed of the vehicle is kept below a maximum speed indicated by the maximum speed value. 
     The output signal may be for providing to a powertrain and/or a brake mechanism of the vehicle to control its speed. 
     An example of an apparatus  101  for controlling movement of a vehicle  202  is shown in  FIG. 1 . The apparatus  10  may comprise an electronic control unit for controlling movement of the vehicle. The apparatus  101  comprises processing means  102 , which, as shown in  FIG. 1 , may comprise an electronic processor  102  arranged to execute instructions  107  stored within an electronic memory device  105  to perform a method embodying the present invention. The instructions may be provided to the memory device  105  via a computer-readable storage medium, for example, a non-transitory storage medium  108 . 
     The processing means  102  is configured to receive first signals from a receiving means  103  arranged to receive transmitted signals from a remote control device indicating a requested motion of a vehicle. The processing means may be arranged to also receive additional signals from sensing means  104  that are located within the vehicle where the processing means  102  is located. The additional signals may comprise information relating to a distance to an obstacle. 
     The processing means  102  is further configured to determine, from the first signals received from the receiving means or an additional signal received from the sensing means  104 , a distance value dependent upon a distance from a point on the vehicle  202  to an obstacle. In the case where the processing means  102  is configured to determine the distance value from the first signals, the first signals may include information relating to the signal strength of the received transmitted signals. 
     The processing means  102  is also configured to determine a maximum speed value for the vehicle  202  in dependence on the determined distance value and provide an output signal  106  for controlling speed of the vehicle  202  based on the requested motion, wherein the output signal  106  is limited dependent upon the maximum speed value. That is, the output signal  106  is dependent upon the requested motion indicated by the signal received from the remote control device, so that the output signal  106  may control, or be used to control, a powertrain of the vehicle and/or a brake mechanism, but the output signal is limited in order to limit the maximum possible speed of the vehicle. 
     An example of a system  201  incorporating the apparatus  101  is shown in  FIG. 2  within a vehicle  202 . The system  201  includes the apparatus  101  of  FIG. 1  and a receiving means  103  in the form of a radio unit. The radio unit  103  may comprise a receiver and a transmitter or, as shown in  FIG. 2 , a transceiver  205  configured to receive radio signals transmitted from a remote control device  204  and transmit signals to the remote control device  204 . The radio unit  103  and the remote control device  204  may be arranged to provide a wireless local area network, via which two-way communication may take place between the radio unit  103  and the remote control device  204 . For example, the radio unit  103  may be arranged to communicate by WiFi with the remote control device  204 . In alternative embodiments other radio communication standards may be used for the communication. In one example, communication between the radio unit  103  and the remote control device is provided via Bluetooth. 
     The remote control device  204  may be a portable device, which may be carried and used by a person  205  outside of the vehicle  202 . In an example, the remote control device  204  comprises a mobile phone (or cell phone) having an application to enable the person  205  to provide manual inputs to request movement of the vehicle  202 . For example, the manual inputs may include an indication of required throttle and braking, or a required speed, as well as required steering. The remote control device  204  is arranged to include data, indicative of the received user inputs, within the signals transmitted to the radio unit  103 . The radio unit  103  is arranged to extract this data and provide the data to the processing means. 
     The radio unit  103  may also comprise a signal strength monitor  206  for measuring the signal strength of the received signals transmitted by the remote control device  204 . The signal strength monitor  206  is arranged to provide first signals to the processing means  102  indicating the strength of the currently received transmitted signal. 
     The system  201  further comprises a number of actuators for effecting movement of the vehicle  202 . In the present embodiment, the actuators comprise a power steering mechanism  207  arranged to provide steering of the wheels of the vehicle in dependence on signals received from the processing means  102 . A second actuator comprises a powered braking mechanism  208  arranged to actuate brakes of the vehicle in dependence on signals received from the processing means  102 . A third actuator comprises a powertrain  209  arranged to provide power, or torque, to cause forward or backward movement of the vehicle in dependence on output signals  106  received from the processing means  102 . 
     The system  201  may also include sensing means  104 , which may comprise proximity sensors  210  that are known for use to assist parking of the vehicle. The proximity sensors  210  may comprise ultrasonic proximity sensors but alternatively may be electromagnetic proximity sensors. Such sensors are known to be provided on vehicles to assist a driver when parking. 
     Each of the proximity sensors  210  may be arranged to provide sensor signals to the processing means  102  indicative of a distance from the sensor to the obstacle nearest to that sensor. The processing means  102  may be configured to process the signals from the sensors  210  by performing sensor fusion (or multi sensor data fusion) to obtain a more accurate indication of the distance from the vehicle  202  to the nearest obstacle to the vehicle. That is, data received from the sensors  210  may be combined so that the resulting indication of distance has less uncertainty than it would have if the data from each sensor were used individually. 
     The sensing means  104  may also comprise one or more cameras  211  located within the vehicle  202  that are configured to provide a signal to the processing means  102  indicative of a distance to a nearest obstacle. 
     The system  201  may also comprise key detection apparatus  212  configured to detect the presence of a smart key  213  of the vehicle  202 , as is known in the art. Such smart keys are known for use with vehicles having a system that allows passive entry to the vehicle and passive start of the vehicle. The key detection apparatus  212  may be arranged to provide a signal to the processing means indicative of whether a smart key  213  for the vehicle  202  has been detected. 
     The key detection apparatus  212  may comprise several key detectors  214  for detecting the smart key  213  and may comprise a processing component  215  for receiving signals from the key detectors  214  and for determining whether the smart key  213  is located inside or outside of the vehicle, as is known. Thus the signal provided to the processing means  102  may also indicate whether the key is inside or outside of the vehicle  202 . In an alternative arrangement, the processing to determine whether the smart key  213  is inside or outside of the vehicle may be performed by the processing means  102 . 
     In one embodiment, the radio unit  103  may be activated by the processing means  102  in response to receiving a key detection signal from the key detection apparatus  212 . For example, a user  205  may be required to bring the smart key  213  within detection distance of the key detection apparatus  212  and wake up the key detection apparatus  212  by pulling a door handle, pressing an unlock button on the vehicle, or another action used for accessing the vehicle. 
     The system  201  enables a person  205  to control movements of the vehicle  202  by remote control by providing user inputs to the remote control device  204 . To enable such remote control, a two-way communication link is firstly established between the remote control device  204  and the radio unit  103 . With the link established the remote control device  204  may then be used to indicate to the processing means  102  that a remote control mode enabling remote control movement of the vehicle  202  is requested. The processing means  102  may determine whether one or more criteria are met before enabling remote control of the vehicle. For example, the processing means  102  may determine whether the smart key  213  is present within the vehicle  102  and if it is, then remote control movement may be disabled or the maximum allowed speed of the vehicle may be set at zero. 
     With the communication link established, the user  205  of the remote control device  204  is then able to provide manual inputs to the remote control device  204  to request movement of the vehicle, including an increase or decrease in speed or power, an increase or decrease braking, and steering. The remote control device  204  may generate data including information defining the requested movement, which is then transmitted to the radio unit  103  via the communication link. 
     The transceiver  205  of the radio unit  103  determines the data defining the movement requested by the remote control device  204  and provides the data to the processing means  102 . The processing means  102  provides output signals to the power steering  207 , the brakes  208  and the powertrain  209  in dependence on the received data, and thus the user  205  is able to operate the vehicle  202  remotely. However, the output signal  106  provided to the brakes  208  and the powertrain  209  may also be dependent upon the maximum speed value mentioned above and which may be determined as described below. Specifically, whatever the speed of vehicle is requested by the remote control device  204 , the processing means  102  provides output signals  106  to the brakes  208  and/or the powertrain  209  to adjust the speed of the vehicle  202  to be no more than a speed corresponding to the maximum speed value. 
     That is, the speed of the vehicle is limited to be no more than a speed corresponding to the maximum speed value. 
     For example, where the data from the remote control device  204  relates to a user request for increased engine power and/or decreased braking that could increase the speed to 3 kilometres per hour, and the maximum speed value corresponds to 1 kilometre per hour, the processing means  102  provides output signals to the brakes and powertrain to cause a speed of only 1 kilometre per hour. 
     In some instances, the speed requested by the remote control device  204  may be unchanged over a period of time, but the determined maximum speed value may become smaller than the current speed of the vehicle and as a result the output signals  106  to the powertrain and/or brakes may be adjusted to reduce the speed of the vehicle so that it corresponds to the maximum speed value. 
     The maximum speed value may be determined in dependence upon signals received by the processing means  102  from the signal strength monitor  206  of the radio unit  103 . The signal strength monitor  206  may measure the power of the signal received from the remote control device  204  and provide a first signal to the processing means indicative of the measured power. The processing means  102  may process the first signal to determine a distance value dependent upon a distance from the aerial  216  of the radio unit  103  to the remote control device  204 . This distance may be regarded as a distance from the vehicle to the user  205  operating the remote control device  204  who provides an obstacle to the movement of the vehicle. 
     The processing means  102  may determine a maximum speed value for the vehicle  202  in dependence on the distance value determined from the first signal. For example, where the distance is relatively small, such as less than two metres, the maximum speed value may be set at a relatively low speed, such as 1 kilometre per hour. This low speed will minimize the possibility of the user  205  of the remote control device  204  accidently causing the vehicle to collide with the user  205 . When the distance is relatively large, such as between 2 metres and 7 metres, the maximum speed value may be set at a larger value, such as 6 kilometres per hour. This will allow the user to move the vehicle at a greater speed when they are at a safe distance from the vehicle. When the distance is determined to be relatively very large, such between 7 metres and 15 metres, the maximum speed value may be set at a relatively smaller value, such as 1 or 2 kilometres per hour. This range of distances may be chosen to be just smaller than the expected limit of the radio link between the remote control device  204  and the radio unit  103 , so that the vehicle is slowed before a loss in radio communication could occur. If the determined distance is very large, for example over 15 metres, the maximum speed value may be set at zero. 
     In embodiments where the processing means  102  also receives a further signal from the key detection apparatus  212 , the maximum speed value may be also dependent upon that further signal. For example, if the smart key is detected outside of the vehicle and the key detection sensors are only capable of detecting the smart key at a distance of a few metres, this indicates that a user who is in possession of the key is also within a few metres of the vehicle, and so the speed of the vehicle should be kept at a relatively low speed to avoid the possibility of the vehicle hitting the user. 
     In embodiments where the processing means  102  is arranged to use the key detection apparatus  212  in this way, the key detection apparatus is maintained in an operational mode while ever the processing means  102  is in its remote control mode. That is, during the remote control mode, the key detection apparatus  212  is caused to repeatedly transmit a signal requesting acknowledgement from the smart key. 
     In arrangements where the processing means  102  also receives additional signals from the sensing means  104 , such as the sensors  210  or cameras  211 , the processing means  102  may determine, from the additional signals, a distance value dependent upon a distance from a point on the vehicle  202  to a nearby obstacle. When the distance to the obstacle is relatively small, it is desirable that the maximum speed of the vehicle is kept relatively low to minimize the possibility of collision with the obstacle. Thus, the processing means  102  may determine a maximum speed value for the vehicle  202  in dependence on the distance value, so that the speed of the vehicle is limited to a relatively low speed when the distance is small and a relatively larger speed when the distance is larger. 
     In an embodiment such as that shown in  FIG. 2 , the maximum speed value may be determined in dependence on the first signals received from the signal strength monitor  206  and the additional signals received from the sensing means  104 . For example, the processing means may be configured to determine a first distance value from the first signals and a second distance value from additional signals received from a sensor and to determine the maximum speed value in dependence on the first distance value or the second distance value. For example, the processing means  102  may be arranged to compare the first distance value and the second distance value to determine which is smallest and determine the maximum speed value in dependence on the smallest one of the first distance value and the second distance value. 
     Alternatively, the processing means  102  may be configured to determine a first maximum speed value from the first signals received from the signal strength monitor  206  and a second maximum speed value from the additional signals received from the sensing means  104  and determine a maximum speed value, which is used to limit the maximum speed of the vehicle, that is the smaller of the first and second maximum speed values. 
     The maximum speed value may also be dependent on the further signals from the key detection apparatus  212 . For example, even if the first signals from the signal strength monitor suggest that the user  205  is relatively distant from the vehicle, the further signals produced by the key detection apparatus  212 , indicating detection of the smart key  213 , may cause the processing means  102  to set the maximum speed value at a relatively low speed. 
     An example of an alternative system  1101  in which the signal strength monitor  206  is omitted is shown in  FIG. 11 . The system  1101  may be just like the system  201  of  FIG. 2  except of the omission of the signal strength monitor. In this embodiment, the maximum speed value may be determined in dependence sensor signals received from the sensing means  104 . The maximum speed value may also be dependent on the further signals from the key detection apparatus  212 . For example, the maximum speed value may be set at a relatively large value, for example 6 kilometres per hour provided no obstacles are detected by the sensing means  104  that are closer than 2.5 metres and/or the smart key  213  is not detected by the key detection apparatus  212 . 
     In alternative systems, the signals from the sensing means  104  may not be taken into account when determining the maximum speed value. An example of a system  1201  that differs from system  201  in that it does not include the sensing means  104  is shown in  FIG. 12 . In this embodiment, the maximum speed value may be determined only in dependence on the first signals received from the signal strength monitor  206 , or may also be dependent upon the further signals from the key detection apparatus  212 . 
     Another alternative system  1301  is shown in  FIG. 13 . The system  1301  differs from system  201  of  FIG. 2  in that it includes a global navigation satellite system (GNSS) module  1302 , such as a GPS (global positioning system) module for receiving satellite signals and determining location data from those signals. The signal strength monitor  206  may be omitted in this embodiment. The remote control device  204  is also provided with a global navigation satellite system module  1303 . The remote control device  204  is arranged to determine its own location from the satellite signals and include location data identifying its location when transmitting to the radio unit  103 . The processing means  102  is arranged to compare the received location data, received via the radio unit  103 , with the location data from the GNSS module  1302  of the vehicle&#39;s system to determine the distance between the vehicle  202  and the remote control device  204 . This distance may then be used as described above, to determine the maximum speed value for the vehicle. 
     Positions of the proximity sensors  210 , cameras  211  and key detectors  214  are shown in a schematic plan view of the vehicle  202  in  FIG. 3 . As is known, the proximity sensors  210  of the vehicle may be arranged at various positions around the periphery of the vehicle  202 . In the present example there are 4 proximity sensors  210 A located at different positions across the front of the vehicle and 4 proximity sensors  2108  located at different positions across the rear of the vehicle  202 . In addition, there are two proximity sensors  210 C located on either side of the vehicle, for example in the wheel arches. 
     In this example the vehicle  202  also has 4 cameras  211 , one each at the front, rear and sides of the vehicle  202 . The vehicle  202  also has five key detectors  214  spaced at different positions around the periphery of the vehicle. 
       FIG. 3  also illustrates three zones  301 ,  302  and  303  that may be defined by the processing means  102 . For example, the first zone  301  may be next to the vehicle  202  and extending up to a relatively short distance from the vehicle. The second zone  302  may surround the first zone and extend up to a larger distance from the vehicle  202 , and the third zone  302  may surround the second zone and extend up to a still larger distance from the vehicle  202 . 
     If the processing means  102  determines that the remote control device  204 , the smart key  213  or another obstacle is within the first zone  301  it may limit the maximum speed of the vehicle  202  to a relatively low value (such as 1 kilometre per hour). The first zone may defined by an outer boundary within which the smart key  204  may be detected and/or within which an obstacle would be determined by one or more sensors  210 A and/or cameras  211  to be within a threshold distance and/or the signal strength monitor  206  would indicate that the remote control device is within a threshold distance. 
     If the processing means  102  determines that the smart key  213  or any other obstacle are not within the first zone  301 , and the remote control device  204  is within the second zone  302 , it may limit the maximum speed of the vehicle  202  to a relatively larger value (such as 6 kilometres per hour). 
     If the processing means  102  determines that the smart key  213  or any other obstacle are not within the first zone  301 , and the remote control device  204  is within the third zone  303 , it may limit the maximum speed of the vehicle  202  to a relatively smaller value (such as 1 or 2 kilometres per hour). This enables the user  205  to ensure that the remote control device  204  is kept within the operating range of its communication link. 
     If the processing means  102  determines that that the remote control device  204  is outside of the outermost, third zone  303 , it may reduce the maximum speed value to zero such that the vehicle is brought to a standstill. 
     Graphs  401  and  402  illustrating an example of how the processing means  102  may determine a maximum speed value just from the signal received from the signal strength monitor  206  are shown in  FIGS. 4A and 4B  respectively. Graph  401  illustrates schematically how power of the received signal received at the radio unit  103  from the remote control device  204  may decrease as distance separating the radio unit  103  and the remote control device  204  increases. Graph  402  shows an example of how the maximum speed value may be selected in dependence upon the determined distance between the radio unit  103  and the remote control device  204 . 
     As illustrated in graph  401 , when the signal power is above a threshold value T 1  it may be estimated that the distance separating the radio unit  103  and the remote control device  204  is relatively small and less than a first distance, D 1 . For distances up to D 1  the maximum speed value may be set at a first speed, S 1 , that is relatively slow. When the signal power is below the threshold value T 1  but above a second threshold value T 2  it may be estimated that the distance separating the radio unit  103  and the remote control device  204  is between the first distance, D 1 , and a larger distance, D 2 . For such distances the maximum speed value may be set at a second speed, S 2 , that is relatively fast (for example 6 kilometres per hour). When the signal power is below the second threshold value, T 2 , but above a third threshold value, T 3 , it may be estimated that the distance separating the radio unit  103  and the remote control device  204  is between the second distance, D 2 , and an even larger distance, D 3 . For such distances the maximum speed value may be set at a third speed, S 3 , that is relatively slow compared to S 2 . When the signal power is below the third threshold value, T 3 , the processing means  102  may determine that the remote control device  204  is outside of an operational range for the system and reduce the maximum speed value to zero. That is, if the received signal strength is below the final threshold value (T 3  in this example) then the motion of the vehicle is stopped. 
     In the example of  FIGS. 4A and 4B , and  FIG. 3 , there are three distance ranges or zones where the vehicle may be remotely controlled and each distance range or zone has an associated maximum speed value. However, alternative examples are envisaged in which only two, or more than three, distance ranges or zones are defined by the processing means, and each distance range or zone has a respective associated maximum speed value. 
     A method  500  of controlling the movement of a vehicle is outlined by the flowchart shown in  FIG. 5 . At block  501  first signals are received from a receiving means in dependence on the receiving means receiving transmitted signals from a remote control device indicating a requested motion of a vehicle. The first signals may be dependent upon the signal strength of the received transmitted signals. Alternatively, the transmitted signals may comprise data dependent upon the location of the remote control device, for example the data may comprise positional data determined from a GNSS module in the remote control device, and the first signal may comprise the received data. In a further alternative embodiment, the remote control device may comprise a signal strength monitor that measures signal strength of signals transmitted by the radio unit of the vehicle and the remote control device then transmits signals to the radio unit of the vehicle that includes data dependent upon the measured signal strength. Thus, the first signals may comprise data that indicates signal strength of signals received by the remote control device from the vehicle. 
     At block  502  a distance value dependent upon a distance from a point on the vehicle to an obstacle is determined. The distance value may be determined from the first signals or an additional signal received from a sensing means, such as the proximity sensors  210  or cameras  211  of  FIG. 2 . 
     At block  503  a maximum speed value for the vehicle is determined in dependence on the distance value calculated at block  502 . 
     At block  504  an output signal is provided for controlling speed of the vehicle based on the requested motion. The output signal is limited dependent upon the maximum speed value. That is, if the requested motion requires a speed that is less than a speed corresponding to the maximum speed value determined at block  503  then the output signal provided to the brakes and powertrain of the vehicle cause the vehicle to attain the required speed. Thus, the output signal may cause reduced braking and/or increased power from the powertrain, if the current speed of the vehicle is less than the required speed, or increased braking and/or decreased power from the powertrain, if the current speed is greater than the required speed. 
     However, if the requested motion requires a speed that is greater than a speed corresponding to the maximum speed value, then the output signal provided to the brakes and powertrain of the vehicle is limited so that the vehicle is only caused to attain the speed corresponding to the maximum speed value. 
     Blocks  501  to  504  are repeatedly performed. The remote control device repeatedly transmits signals to the radio unit of the vehicle indicating the currently requested movement of the vehicle, and the radio unit repeatedly receives the transmitted signal. The determination of a distance value is similarly repeated, either from the most recently received signal from the remote control device or from signals received from sensing means on the vehicle, or a combination of these signals. Similarly a maximum speed value is repeatedly determined at block  503  in order to set the limit on the output signal at block  504 . 
     A method  600  of controlling the movement of a vehicle is outlined by the flowchart shown in  FIG. 6 . At block  601  first signals are received from a receiving means in dependence on transmitted signals being received from a remote control device indicating a requested motion of a vehicle. Block  601  may be the same as block  501  described above. At block  602 , a first distance value is determined from the first signals. An example of the process  602  of determining the first distance value is shown in the flowchart of  FIG. 8 . The signal strength of received transmitted signals, such as the signals transmitted by the remote control device  204  of  FIG. 2  and received by the radio unit  103 , is compared to at least one threshold value to determine a distance value in dependence on the comparison. Thus, this process is as described above with regard to the graphs of  FIGS. 4A and 4B . 
     At block  603  a second distance value is determined from at least one additional signal received from a sensing means. An example of the process of block  603  is shown in the flowchart of  FIG. 9 . At block  901  a plurality of additional signals are received, for example by the processing means  102  of  FIG. 2 . Each additional signal may be received from a respective one of a plurality of sensors, such as proximity sensors  210  or cameras  211 . At block  902  a process of sensor fusion may be performed to obtain the second distance value. As an alternative to the processes of  FIG. 9 , the process at block  603  may comprise receiving the additional signal(s) from a single sensor or the additional signal may be the result of fusion of several sensors performed prior to receipt by the processing means  102 . 
     At block  604  a maximum distance value is determined for the vehicle in dependence on the first distance value or the second distance value found at block  603 . For example, at block  604 , the first and second distance values may be compared and the smallest distance value may be used to determine the maximum speed value. Alternatively, as shown in  FIG. 10 , the process at block  604  may comprise determining a first speed value from the first distance value at block  1001  and determining a second speed value from the second distance value at block  1002 . A maximum speed value may then be determined as the smaller one of the first speed value and the second speed value at block  1003 . 
     For example, the second distance value may indicate that the nearest obstacle to the vehicle is in the second zone  302  of  FIG. 3  and therefore a relatively high second speed value may be determined, but the first distance value may indicate that the person  205  using the remote control device  204  is within the third zone  303  of  FIG. 3  and therefore a relatively low first speed value may be determined. That is, a first speed value may be determined that is lower than the second speed value. Consequently, the maximum speed value is determined at block  1003  to be the relatively low first speed value, rather than the speed value determined in respect of the nearest obstacle. 
     Following block  604 , an output signal for controlling the speed of the vehicle based on the requested motion is provided at block  605 . For example, the output signal may cause reduced braking and/or increased power from the powertrain, if the current speed of the vehicle is less than the required speed, or increased braking and/or decreased power from the powertrain, if the current speed is greater than the required speed. However, the output signal is limited dependent upon the maximum speed value that was determined at block  604 , so that the speed of the vehicle does not exceed a speed corresponding to the maximum speed value. For example, the requested motion of the vehicle may include a speed that is greater than a speed corresponding to the maximum speed value determined at block  604 , in which case the output signal is limited in order to limit the speed of the vehicle to a speed corresponding to the maximum speed value. 
     A flowchart showing additional processes  701 ,  702  and  703  that may be incorporated into the method  500  of  FIG. 5 , for example following block  503 , or the method  600  of  FIG. 6 , for example following block  604 , are shown in  FIG. 7 . At block  701  a further signal is received, for example by processor  102 , from a key detection means, such as apparatus  212 , that is configured to receive signals from a smart key of the vehicle. At block  702  the maximum speed value is set to a relatively low value when the further signal is indicative of a smart key being detected outside of the vehicle. Thus, this maximum speed value determined at block  702  may be used in preference to the maximum speed value determined previously at blocks  503  or  604 . 
     At block  703  the maximum speed value is set to correspond to a vehicle speed of zero when the further signal is indicative of the smart key being within the vehicle. 
     For purposes of this disclosure, it is to be understood that the processing means described herein can each comprise a control unit or computational device having one or more electronic processors. A vehicle and/or a system thereof may comprise a single control unit or electronic controller or alternatively different functions of the controller(s) may be embodied in, or hosted in, different control units or controllers. A set of instructions could be provided which, when executed, cause said controller(s) or control unit(s) to implement the control techniques described herein (including the described method(s)). The set of instructions may be embedded in one or more electronic processors, or alternatively, the set of instructions could be provided as software to be executed by one or more electronic processor(s). For example, a first controller may be implemented in software run on one or more electronic processors, and one or more other controllers may also be implemented in software run on or more electronic processors, optionally the same one or more processors as the first controller. It will be appreciated, however, that other arrangements are also useful, and therefore, the present disclosure is not intended to be limited to any particular arrangement. In any event, the set of instructions described above may be embedded in a computer-readable storage medium (e.g., a non-transitory storage medium) that may comprise any mechanism for storing information in a form readable by a machine or electronic processors/computational device, including, without limitation: a magnetic storage medium (e.g., floppy diskette); optical storage medium (e.g., CD-ROM); magneto optical storage medium; read only memory (ROM); random access memory (RAM); erasable programmable memory (e.g., EPROM ad EEPROM); flash memory; or electrical or other types of medium for storing such information/instructions. 
     The blocks illustrated in the  FIGS. 5 to 10  may represent steps in a method and/or sections of code in the computer program  107 . The illustration of a particular order to the blocks does not necessarily imply that there is a required or preferred order for the blocks and the order and arrangement of the block may be varied. Furthermore, it may be possible for some steps to be omitted. 
     Although embodiments of the present invention have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the invention as claimed. 
     Features described in the preceding description may be used in combinations other than the combinations explicitly described. 
     Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not. 
     Although features have been described with reference to certain embodiments, those features may also be present in other embodiments whether described or not. 
     Whilst endeavoring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.