Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
  • G01B7/30—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring angles or tapers; for testing the alignment of axes
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
  • G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
  • G01C21/10—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration
  • G01C21/12—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning
  • G01C21/16—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning by integrating acceleration or speed, i.e. inertial navigation
  • G01C21/166—Mechanical, construction or arrangement details of inertial navigation systems
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
  • B60Q1/00—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor
  • B60Q1/26—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic
  • B60Q1/34—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic for indicating change of drive direction
  • B60Q1/38—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic for indicating change of drive direction using immovably-mounted light sources, e.g. fixed flashing lamps
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
  • B60Q1/00—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor
  • B60Q1/26—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic
  • B60Q1/34—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic for indicating change of drive direction
  • B60Q1/38—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic for indicating change of drive direction using immovably-mounted light sources, e.g. fixed flashing lamps
  • B60Q1/381—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic for indicating change of drive direction using immovably-mounted light sources, e.g. fixed flashing lamps with several light sources activated in sequence, e.g. to create a sweep effect
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
  • B60T8/17—Using electrical or electronic regulation means to control braking
  • B60T8/171—Detecting parameters used in the regulation; Measuring values used in the regulation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units, or advanced driver assistance systems for ensuring comfort, stability and safety or drive control systems for propelling or retarding the vehicle
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units, or advanced driver assistance systems for ensuring comfort, stability and safety or drive control systems for propelling or retarding the vehicle
  • B60W30/02—Control of vehicle driving stability
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W40/00—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models
  • B60W40/10—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models related to vehicle motion
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W40/00—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models
  • B60W40/10—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models related to vehicle motion
  • B60W40/103—Side slip angle of vehicle body
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
  • G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
  • G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
  • G01C21/10—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration
  • G01C21/12—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning
  • G01C21/16—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning by integrating acceleration or speed, i.e. inertial navigation
  • G01C21/183—Compensation of inertial measurements, e.g. for temperature effects
  • G01C21/188—Compensation of inertial measurements, e.g. for temperature effects for accumulated errors, e.g. by coupling inertial systems with absolute positioning systems
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
  • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
  • G01P15/14—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of gyroscopes
• • G—PHYSICS
  • G08—SIGNALLING
  • G08G—TRAFFIC CONTROL SYSTEMS
  • G08G1/00—Traffic control systems for road vehicles
  • G08G1/16—Anti-collision systems
  • G08G1/161—Decentralised systems, e.g. inter-vehicle communication
  • G08G1/163—Decentralised systems, e.g. inter-vehicle communication involving continuous checking
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
  • B60Q1/00—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor
  • B60Q1/26—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic
  • B60Q1/32—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic for indicating vehicle sides, e.g. clearance lights
  • B60Q1/326—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic for indicating vehicle sides, e.g. clearance lights on or for wheels
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W2420/00—Indexing codes relating to the type of sensors based on the principle of their operation
  • B60W2420/50—Magnetic or electromagnetic sensors
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W2420/00—Indexing codes relating to the type of sensors based on the principle of their operation
  • B60W2420/90—Single sensor for two or more measurements
  • B60W2420/905—Single sensor for two or more measurements the sensor being an xyz axis sensor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W2422/00—Indexing codes relating to the special location or mounting of sensors
  • B60W2422/70—Indexing codes relating to the special location or mounting of sensors on the wheel or the tire

Definitions

• the invention relates to detecting directions at a wheel and more particularly to detecting directions by an inertial unit arranged to the wheel.
• An inertial unit is an electronic device that measures and reports on a craft's velocity, orientation, and gravitational forces, using a combination of accelerometers and gyroscopes, sometimes also magnetometers.
• Inertial units are typically used to maneuver aircraft, including unmanned aerial vehicles (UAVs), among many others, and spacecraft, including satellites and landers.
• UAVs unmanned aerial vehicles
• satellites and landers including satellites and landers.
• GPS Global Positioning System
• the inertial unit-enabled GPS allows uninterrupted position service when GPS-signals are unavailable, such as in tunnels, inside buildings, or when electronic interference is present.
• the inertial unit is the main component of inertial navigation systems used in aircraft, spacecraft, watercraft, and guided missiles among others.
• the data collected from the inertial unit's sensors allows a computer to track a craft's position, using a method known as dead reckoning.
• an apparatus comprising an inertial unit for being attached to a wheel of a vehicle, said inertial unit arranged to detect directions at plane defined by circumference of the wheel for providing angular information and a controller coupled to the inertial unit for processing the angular information, wherein the method comprises, measuring angular information, determining a steering operation of the vehicle on the basis of the measurement results of the angular information.
• an apparatus comprising an inertial unit for being attached to a wheel of a vehicle, said inertial unit arranged to detect directions at plane defined by circumference of the wheel for providing angular information, and a controller coupled to the inertial unit for processing the angular information, wherein the apparatus comprises means to perform the steps of a method according to an aspect of the present invention.
• an a stability control system for a vehicle comprising one or more wheels and an apparatus according to aspect of the present invention attached to the one or more wheels, wherein the stability control system is connected to the apparatuses for obtaining information, for example angular information, wheel wear information and/or lateral sliding information.
• an inertial unit for being attached to a rotatable part of a vehicle, the rotatable part being coupled to a power equipment of the vehicle, the inertial unit comprising: at least one acceleration sensor and/or at least one magnetometer arranged to detect a tilting angle of the rotatable part, and/or at least one counter device arranged to detect rotations of the rotatable part, and at least one gyroscope arranged to detect directions at a rim level of the rotatable part for providing angular information for positioning.
• an apparatus for being attached to a rotatable part of a vehicle, the rotatable part being coupled to a power equipment of the vehicle comprising: at least one acceleration sensor and/or at least one magnetometer arranged to detect a tilting angle of the rotatable part, and/or at least one counter device arranged to detect rotations of the rotatable part, and at least one gyroscope arranged to detect directions at a rim level of the rotatable part for providing angular information for positioning, and means for processing data, the data comprising the detected tilting angle and/or detected rotations and the angular information, by using the tilting angle and/or the detected rotations for at least one coordinate system transformation and by using rotation of the rotatable part for compensating gyroscope bias for compensating inaccuracy of the angular information.
• a method comprising: obtaining data on a tilting angle of a rotatable part of a vehicle and/or rotations and angular information, and processing the data by using the tilting angle and/or the detected rotations for at least one coordinate system transformation and by using rotation of the rotatable part for compensating gyroscope bias for compensating inaccuracy of the angular information.
• an apparatus comprises an indicator coupled to the controller, wherein the indicator is for emitting a signal indicating a steering operation of the vehicle to a steering direction
• the method according to an aspect of the present invention comprises defining a threshold for the measured angular information corresponding to the steering direction of the vehicle, determining when the angular information meets the threshold, and set the indicator, when the threshold is met.
• the indicator may comprise an illuminator, for example a lamp, light emitting diode, or a radio frequency transmitter, said radio frequency transmitter being preferable a directional radio frequency transmitter.
• an illuminator for example a lamp, light emitting diode, or a radio frequency transmitter, said radio frequency transmitter being preferable a directional radio frequency transmitter.
• Some aspects provide improvements comprising determining steering direction of the vehicle, when GPS is not available and without human intervention. Some aspects provide improved safety in driving vehicles by setting an indicator when a steering operation, steering direction, lateral sliding and/or wheel wear is determined.
• Figure 1 illustrates an example of an inertial unit
• Figure 2 illustrates an example of an apparatus
• Figure 3 is a flow chart
• FIG. 4 illustrates an exemplifying application
• FIG. 5 illustrates another exemplifying application
• Figure 6a illustrates an apparatus attached to a wheel, according to an embodiment
• Figure 6b illustrates a plurality of apparatuses attached to a single wheel according to an embodiment
• Figure 7 illustrates a stability control system for a vehicle and wheels in different steering directions of the vehicle according to an embodiment
• Figure 8a illustrates operation of indicators in the steering direction according to an embodiment
• Figure 8b illustrates operation of indicators in the steering direction of the vehicle and operation of indicator not in the steering direction, according to an embodiment
• Figure 9 illustrates a method according to an embodiment
• Figures 10a and 10b illustrate angular information obtained from a wheel. Description of some embodiments
• Acceleration sensors or accelerometers are designed to detect changes in force resulting from fall, tilt, motion, positioning, shock and/or vibration. They may be produced based on MEMS-technology as well. Acceleration sensors or accelerometers are used in positioning applications.
• a magnetometer is a measuring device used to measure the strength or direction of magnetic fields. Magnetometers are used in positioning applications.
• a gyroscope is a device designed for measuring or maintaining orientation usually by measuring angular rate of turn in relation to a defined axis. Gyroscopes may be manufactured based on several techniques, but micro electrical mechanical system (MEMS) gyroscopes are becoming most popular especially in consumer electronics and other large scale applications and products due to their low manufacturing costs, size and low power consumption. MEMS gyroscopes are typically vibratory gyroscopes. Gyroscopes are used in positioning applications. Gyroscopes implemented by using MEMS-technology are inferior in accuracy to ring laser gyroscopes or interferometric fiber optic gyroscopes, for instance, due to errors caused by bias. Hence, traditional inertial navigation methods based on accurate gyroscopes are typically not suitable as such when MEMS-based inertial units are used, but methods for improving the accuracy are required.
• MEMS micro electrical mechanical system
• the quality of a MEMS gyroscope is usually defined by the magnitude of a constant additive unpredictable part of bias errors.
• the angular rate measurement outputs from one or more MEMS gyroscopes are usually integrated to obtain change in orientation, for example an angle value which expresses the change in the heading of a vehicle.
• constant bias errors in angular rate are also integrated into an angle error.
• the constant part of a bias may be at least partly cancelled by means of carouseling.
• Carouseling typically involves controlled rotation of the device used for positioning in relation to one or more axes. Additionally, the carouseling needs means to provide a desired angle change.
• Another method is to make measurements when a vehicle of interest is not moving and then averaging the measurement results to obtain an estimate of the bias.
• a repetitive rotation is usually required and information on the time when a full (360°) revolution circulation is completed.
• a rotation of a wheel may be utilized: wheels rotate when the vehicle moves and this rotation may be measured by the vehicle itself or using additional sensors.
• an apparatus providing information for positioning may be attached to the wheel or tyre or any other rotatable part (such as a pedal or treadle) of a vehicle which part is related to the movement of the vehicle.
• a vehicle may be any device or means of conveyance which moves by using one or more rotating wheels or tyres, such as a car, truck, trailer truck, lorry, van, tractor, fork-lift, motor bike, cycle, moped, camper, earth-mover, vehicles or machines used in mines or harbours, etc.
• Embodiments are suitable for vehicle positioning and navigation purposes for instance when global positioning system (GPS), global navigation satellite system (GNSS) or other corresponding signals are not available.
• GPS global positioning system
• GNSS global navigation satellite system
• One embodiment may be carried out by an inertial unit which is attachable to the wheel of a vehicle.
• the inertial unit is attachable to a rotatable part of a vehicle, the rotatable part being coupled to a power equipment of the vehicle directly or indirectly (indirectly may for instance mean that the rotatable part may be a back wheel, when the vehicle is front-driven).
• the rotatable part may be a wheel, tyre, crank arm, etc.
• Term "power equipment” is used to describe motors, engines, power transmission means, accumulators, drives, bicycle chains, etc. It should be appreciated that a normal steering wheel is usually not suitable for the embodiment (no regular repetitive rotation).
• Figure 1 One example of an inertial unit is shown in Figure 1 .
• the exemplifying inertial unit 100 comprises: at least one acceleration sensor and/or at least one magnetometer arranged to detect a tilting angle of the rotatable part, and/or at least one counter device 102 arranged to detect rotations of the rotatable part, and at least one gyroscope 104 arranged to detect directions at a rim level of the rotatable part for providing angular information for positioning.
• Another embodiment is an apparatus which is attachable to a rotatable part of a vehicle, the rotatable part being coupled to a power equipment of the vehicle.
• the rotatable part may be a wheel, tyre, pedal or treadle, etc.
• Term "power equipment” is used to describe motors, engines, power transmission means, accumulators, drives, bicycle chains, etc. It should be appreciated that a normal steering wheel is usually not suitable for the embodiment.
• One example of an apparatus is depicted in Figure 2.
• the exemplifying apparatus 200 comprises: at least one acceleration sensor and/or at least one magnetometer arranged to detect a tilting angle of the rotatable part, and/or at least one counter device 202 arranged to detect rotations of the rotatable part, at least one gyroscope 204 arranged to detect directions at a rim level of the rotatable part for providing angular information for positioning and means 210 for processing data, the data comprising the detected tilting angle and/or detected rotations and the angular information, by using the tilting angle and/or the detected rotations for at least one coordinate system transformation and by using rotation of the rotatable part for compensating gyroscope bias for compensating inaccuracy of the angular information.
• the means for processing data may be or comprise a processor, chip set, a unit or module comprising a plurality of processors, a computer program product, or a medium comprising a computer program.
• the medium may be any entity or device capable of carrying the program and it may be a non-transitory medium.
• Computer programs, also called program products or programs, including software routines, applets and macros, may be stored in any apparatus-readable data storage medium and they include program instructions to perform particular tasks.
• Computer programs may be coded by a programming language, which may be a high-level programming language, such as objective-C, C, C++, C#, Java, etc., or a low-level programming language, such as a machine language, or an assembler.
• An indicator 212 is coupled to the processing means.
• the connection between the indicator and the processing means may be an electrical connection implemented for example as a galvanic, inductive or capacitive connection.
• a galvanic connection may be provided by an electrical conductor, for example an electrical wire.
• the indicator may comprise an illuminator, for example a lamp or a Light Emitting Diode (LED), or a radio frequency transmitter, said radio frequency transmitter being preferably a directional radio frequency transmitter.
• the indicator has an operating direction, where it emits a signal that indicates a steering operation of the vehicle.
• the emitted signal may comprise visible light or a radio frequency signal.
• the signal may encode a message.
• the message may be encoded using modulation techniques known to the skilled person.
• the message may comprise information comprising positioning information of the vehicle.
• the positioning information may be provided using a suitable coordinate system, for example the World Geodetic System (WGS) 84 used by the Global Positioning System.
• WGS World Geodetic System
• the apparatus may be implemented by various means, for example by hardware (one or more devices), firmware (one or more devices), software (one or more modules), or combinations thereof.
• a software application may be a computer program designed to carry out required computations, otherwise an inertial unit usually comprises hardware parts alone or in combination with software.
• the computer program may be stored in a computer readable media, such as magnetic disks, cards, tapes, etc.
• the required number of acceleration sensor is typically two to provide direction information for trajectory computation.
• the apparatus or inertial unit may also comprise means for storing data, such as one or more memory units 106 or 206.
• the memory units may include volatile and/or non-volatile memory.
• the memory unit may store computer program code and/or operating systems, information, data, content or the like for the processor to perform operations according to embodiments.
• Each of the memory units may be a random access memory, hard drive, etc.
• the memory units may be at least partly removable and/or detachably operationally coupled to the apparatus.
• the memory may be of any type suitable for the current technical environment and it may be implemented using any suitable data storage technology, such as semiconductor-based technology, flash memory, magnetic and/or optical memory devices.
• the memory may be fixed or removable.
• the apparatus or the inertial unit may also comprise means for communicating 108 or 208 with an apparatus configured to process data the inertial unit obtains.
• the means may be a radio transceiver/transmitter or a radio link (Bluetooth ⁇ , Zigbee ⁇ , WiFi ⁇ , wireless local area network (WLAN), radio frequency identification (RFID), etc.).
• RFID radio frequency identification
• the inertial unit may comprise or be coupled to a communication unit, which may encode data and convey it to a processing unit, such as a global positioning (GPS) device, or any other device having suitable data processing facilities.
• the communication unit may also count rotations of the rotatable part. In this case, if speed is fast enough, it is possible that data obtained by acceleration sensors or magnetometers may not be necessary, but it may be used for improving accuracy. Yet another option is a counter device the examples of which are explained below.
• the embodiment starts in block 300 of Figure 3.
• the information may be obtained by using a radio transceiver/receiver or a radio link (Bluetooth ⁇ , Zigbee ⁇ , WiFi ⁇ , WLAN, RFID, etc.).
• a radio transceiver/receiver or a radio link Bluetooth ⁇ , Zigbee ⁇ , WiFi ⁇ , WLAN, RFID, etc.
• Another option is to use magnetic coding used in smart card applications, such as credit cards.
• the magnetic encoded data may be remote read.
• the data may be obtained internally as in common electronic devices and conveyed after processing to further applications, such as to be shown on an electronic map or for applications using augmented reality for controlling vehicles or machines.
• Tilting angle expresses the angular position of a rotatable part, such as a wheel, tyre, pedal or treadle.
• the tilting angle is used to refer to an angle defined by tilting of the X and Y -axes of the coordinate system of the wheel by rotating the Z-axis of the wheel. Accordingly, the tilting angle defines the difference of the different coordinate systems by the difference between directions of the X and Y axes of the coordinate systems.
• Figure 4 illustrates coordinate systems in relation to the wheel and in relation to the vehicle structure, where the X and Y -axes of the wheel's coordinate system may be tilted with respect to the vehicle's coordinate system.
• the tilting angle may be defined by an angle between 0 and 2 ⁇ .
• the data is processed by using the tilting angle and/or the detected rotations for at least one coordinate system transformation and by using rotation of the rotatable part for compensating gyroscope bias for compensating inaccuracy of the angular information.
• m B denotes a vector in frame B
• m A denotes a vector in frame A
• A denotes an original frame
• the direction cosine matrix may be determined as follows: cos(u,e 2 ) cos(u, e 3 )
• i ib is a skew symmetric matrix of a form: wherein the matrix Q b ib is formed by using information obtained by a gyroscope (scalars p, q, r) in relation to three axes:
• T denotes a transpose of a matrix
• one or two of the scalars may be replaced by information obtained from an accelerometer, magnetometer (or a counter device that counts full revolutions).
• an accelerometer typically, only one or two gyroscopes are required.
• accelerometers or magnetometers is to use a brake disc or a brake block on combination of a switch or magnet.
• a permanent magnet for counting full revolutions may be used.
• the combination of a brake disc or a brake block and a magnet or switch is called a counter device.
• a dynamo may be used to obtain energy from the rotation of a rotatable part.
• V-coordinate system 402 is in relation to vehicle structure 400 and A- coordinate system 404 is in relation to a wheel (rotatable part) 406 of the vehicle 400.
• an inertial unit is attached to the wheel 406 to detect directions at plane defined by circumference of the wheel for providing angular information, whereby the measurements of the inertial units are provided in the coordinate system of the wheel.
• the wheel rotates in the direction of travel and defines a plane by its circumference.
• the measured angular information in the A-coordinate system may be transformed to the V- coordinate system to be used in various purposes, for example in vehicle positioning, determining steering operation, determining steering direction, determining lateral-sliding and determining wear of the wheel .
• the angle of phase difference or a phase angle in other words how much a rotatable part, such as a wheel, is rotated when the vertical axis (X- axis) of the A-coordinate system points upwards.
• the angle of phase difference may be unlimited and thus obtain values over 2 ⁇ . It should be appreciated that the phase angle and the tilting angle may be the same, at least when the phase angle is between 0 and 2 ⁇ similar to the tilting angle.
• These state variables may be obtained by multiplying the angle of phase difference by a known radius of the rotatable part.
• the angle of this turn may be detected by using an additional coordinate system, namely E-coordinate system 504.
• the V-coordinate 502 system is in relation to the vehicle or vehicle structure 500
• the E-coordinate system is in relation to a map or screen etc. in such a manner, that the E-coordinate system shows map north or one or more other corresponding directions.
• the angle of the vehicle (heading) may be detected by comparing V-coordinate system and E-coordinate system. This gives information on the vehicles direction (w) in two-dimensional space.
• An example of a trajectory is shown by a reference number (506).
• Easting for example
• y denotes a coordinate point in relation to a second horizontal axis (Northing, for example)
• z denotes a coordinate point in relation to the axis depicting depth or third dimension (zero in 2D applications),
• T denotes matrix transpose
• Location information may be estimated or updated by: wherein,
• Ad denotes change in covered distance in a predetermined period of time
• C y denotes transformation from a vehicle's coordinate system to coordinate system of the applications, such as a map.
• the matrix C y may be estimated or updated or estimated by using data obtained by a gyroscope when transformed to the V-coordinate system.
• the data is typically an integral of the change in a phase angle. If multiple gyroscopes are used, the data may be in a vector form. In one embodiment two gyroscopes are used and the measurements may be carried out at a rim level with about 90° angular spacing.
• the rim level of the wheel may be defined by a plane defined by the wheel as described in Figures 6a and 6b.
• the angle of phase difference or phase angle of a rotatable part may be estimated in a plurality of manners. This phase angle is used to form direction matrix C B A using Equation (2). Two examples are herein explained in further detail.
• ml denotes a reading of a first accelerometer
• ml denotes a reading of a second accelerometer.
• the acceleration sensors or magnetometers are typically placed on a same axis (same axes) than gyroscopes.
• measurements should be taken frequently enough in order to cancel constant bias of gyroscopes at least substantially.
• measurement signals set constant terms to zero as the sum of samples ml over a full rotation is very close to zero and sum of samples m2 over a full rotation is very close to zero as well.
• the moment when a full rotation is completed is estimated or detected and data (angular rates) with regard to one rotation is gathered from at least one gyroscope.
• the gyroscope data of a first gyroscope is multiplied by sine series and the gyroscope data of second gyroscope is multiplied by cosine series, both series selected in such a manner that they represent as accurately as possible the ml and m2 accelerometer series (see the previous example), and that the sum of the series is zero as exactly as possible.
• the constant part of gyroscope bias is cancelled (at least partly).
• Suitable sine and cosine series may be pre-defined by simulations, and may be tabulated beforehand.
• Simple method suitable for slow moving vehicles is to follow acceleration signals and study zero crossings: in the case of two acceleration sensors, the direction can be deduced by observing which one crossing the zero first. Additionally, each zero crossing (from negative to positive, for example) is taken as a full rotation of a rotatable part.
• a filter that is suitable for estimating a state by using noisy observations such as a Kalman filter, may be applied in angle estimation. Kalman filtering may be used to improve estimation of the angle of a rotatable part and thus to make estimation of zero crossings easier.
• a simple switch, or magnet in combination of a brake disc or block, or similar counter device may be used to detect full 360° rotations, in which case sine and cosine series may be generated to be equal in length of the gyroscope data samples obtained during the time of the full rotation.
• the embodiment ends in block 306.
• the embodiment is repeatable in many ways. One example is shown by arrow 308 in Figure 3.
• Figure 6a illustrates an apparatus attached to a wheel, according to an embodiment.
• the apparatus may be the apparatus according to Figures 1 or 2.
• the apparatus 602 is attached to the wheel at the rim level of the wheel 606a.
• the rim level of the wheel may be defined by circumference of the wheel that defines a plane 603.
• a plurality of the apparatuses 602 are attached to a single wheel 606b, according to an embodiment. In this way the apparatuses are attached to each steering direction of the wheel at the rim levels of the wheel 606b defining planes 605, 607 similar to Figure 6a. Indicators of the apparatuses may then indicate the steering operation of the wheel to corresponding steering directions.
• the apparatus is attached to the wheel at the wheel hub, however, also other locations may be used provided that the axes on which the inertial unit is arranged to detect directions may be arranged at the rim level.
• Figure 4 illustrates axes 404 of the inertial unit that is attached to the wheel.
• the apparatus attached to the wheel in Figures 6a and 6b comprises the apparatus of Figure 2 that comprises an indicator.
• the emission direction of signals from the indicator is preferably directed outwards from the wheel.
• the arrangement of Figure 6a is preferred, when the wheel is mounted to a vehicle such that one side of the wheel is blocked, whereby attaching the apparatus and the indicator on that side of the wheel would be difficult and signals of the indicator would be very likely blocked by the vehicle structure, for example the wheel being installed with respect to the vehicle structure 400 according to Figure 4.
• the apparatus may be attached to the side of the wheel corresponding to the steering direction, where the wheel is open, e.g. viewable, and signals may be emitted by the indicator on the wheel.
• the arrangement of the apparatuses and the wheel in Figure 6b is preferable, when the wheel is open towards both steering directions for emitting signals by the indicator. This is the case for example in motorcycles and harbor cranes, where the wheel is mounted in a fork-like structure and the sides of the wheel are visible to the steering directions, whereby signals may be emitted by the indicator on the wheel.
• Figure 7 illustrates a stability control system 704 for a vehicle and wheels 706a, 706b in different steering directions of the vehicle according to an embodiment.
• the steering directions may be opposite directions, for example left and right as is typical for example in cars.
• An apparatus 702 according to an embodiment is installed to both of the wheels.
• the apparatus may be the apparatus of Figures 1 or 2 installed to the wheels as described in Figures 6a or 6b.
• the stability control system may connect to the apparatuses installed to the wheel using a wireless connection that may be implemented by the stability control system and the apparatuses implementing corresponding communications means, for example the communications means illustrated in Figures 1 and 2.
• the connection between the stability control system and the wheels provides the stability control system to obtain angular information, wheel wear information and/or acceleration information from the apparatuses installed to the wheels.
• Typical operations of conventional stability control systems include monitoring wheels and controlling power conveyed to the wheels.
• the angular information, wheel wear information and/or acceleration information, for example lateral sliding information, from the apparatuses installed to the wheels improves the accuracy of the monitoring and controlling functions of the stability control system.
• the stability control system may comprise a user interface through which information may be presented to a user and the user may enter commands.
• the user interface may comprise one or more or a combination of: user operable keys, touch screens, LEDs, lamps.
• Figure 8a illustrates operation of indicators 802a, 802b, 802c, 802d in a steering direction according to an embodiment.
• the indicators may be provided by apparatuses according to Figure 2 being attached to wheels of a vehicle 804a. The attachment may be implemented as described in Figure 6a.
• the vehicle is steered right and the trajectory 806a of the vehicle is curved for the period of the steering operation.
• the indicators 802b, 802d installed to the wheels in the steering direction i.e. on the side of the inner curb of the vehicle trajectory, are set. Signals emitted by the set indicators are illustrated by areas 808.
• Indicators 802a, 802c are installed to the wheels that are in different direction to the steering of the vehicle and the indicators are not set. Since the indicators emit signals only in the direction, where the vehicle is begin steered, the communications from the indicators to the environment of the vehicle may be straightforwardly interpreted as an event that needs to be considered when observed so as to avoid any collisions.
• vehicle 804b is steered left and the trajectory 816a of the vehicle is curved.
• the indicators 812a, 812c installed to the wheels in the steering direction i.e. on the side of the inner curb of the vehicle trajectory, are set.
• Signals emitted by the set indicators on the left side of the vehicle are illustrated by areas 818. In this way information may be emitted towards the direction, where the vehicle is steered and personnel or equipment receiving the emitted information from the indicators may take action to avoid collisions with the turning vehicle, similar to Figure 8a.
• Indicators 812b, 812d are directed in different direction than the steering direction and they are set to emit a different signal than the indicators in the steering direction. Signals emitted by the set indicators on the right side of the vehicle are illustrated by areas 828. In this way the personnel and equipment that are moving in the environment of the vehicle may be communicated by the emitted different signals whether the vehicle is moving into a steering direction or away from the steering direction. Since the movement of the vehicle away from the steering direction may be identified, vehicles and personnel in within the range of the emitted signals may identify that braking may not be needed, since the turning vehicle is moving away.
• Figure 9 illustrates a method according to an embodiment.
• the method may be performed by an apparatus in Figure 2.
• the method may be executed to perform the operation of Figures 8a or 8b, for example.
• the apparatus performing the method comprises an inertial unit for being attached to a wheel of a vehicle. It is also possible that the apparatus is communicating with the inertial unit to receive measurements from the inertial unit.
• the inertial unit is arranged to detect directions at plane defined by circumference of the wheel for providing angular information for positioning.
• the angular information may comprise angular rate ⁇ , for example.
• the inertial unit may be attached to the wheel as described in Figures 6a and 6b.
• the detection directions of the inertial unit may be arranged to the plane defined by the circumference of the wheel, i.e.
• Figure 4 illustrates the detection directions by X and Y axes that are preferably according to the Cartesian coordinates.
• the method starts in 902, where the inertial unit or the apparatus itself is installed to one or more wheels of a vehicle and the vehicle is being driven, whereby the wheels are rotated on a surface for example a road.
• angular information is measured by the inertial unit.
• the measurement may be performed by gyroscopes arranged at the plane of the wheel defined by circumference of the wheel.
• the plane may be defined by X and Y -axes and perpendicular to Z axis according to the axes 404 on the wheel 406 illustrated in Figure 4. Accordingly, the gyroscopes measure directions at the rim level of the wheel.
• the gyroscopes are preferably arranged on axes on the plane according to the Cartesian coordinate system, where the axes are at 90 degrees angle with respect to each other.
• the measured angular information is used to determine steering operation of the vehicle, steering direction of the vehicle, wear of the wheel and/or lateral sliding of the vehicle.
• An illustration of the measured angular information is provided in Figures 10a and 10b.
• the determining involves processing of the angular information. If steering operation of the vehicle, steering direction of the vehicle, wear of the wheel and/or lateral sliding of the vehicle are not determined the method ends in 914 without setting an indicator.
• Figure 10a illustrates angular information obtained from the inertial unit.
• the angular information comprises angular rate measured with respect to X and Y axes of the inertial unit.
• the angular information is measured in the coordinate system of the wheel, for example according to the axes illustrated in Figure 4, when the inertial unit is attached to the device according to Figure 6a.
• the steering operation may be determined on the basis of the peaks in the measured angular information.
• a steering operation enables turning of the vehicle.
• the trajectory of the vehicle is curved, whereby the vehicle experiences centripetal acceleration towards the inner curb, in the steering direction.
• the vehicle is driving straight.
• Steering may be implemented by various ways depending on the vehicle that is steered.
• the steering is conventionally actuated by the driver turning the steering wheel, where the steering direction is communicated to one or more wheels for turning the wheels.
• the steering operation may also be automated in vehicles, for example in the driverless car developed by Google and in many industrial vehicles that have at least partly automatic steering.
• a vehicle may be steered without a steering wheel by external equipment to the vehicle.
• the external equipment are rails that steer a railway engine or a railway car moving on the rails in the direction of the rails.
• the angular information may be used to determine, whether the vehicle is steered into a direction that causes curving the trajectory of the vehicle.
• a threshold may be defined for the angular information and the steering operation may be determined 906 on the basis of the angular information meeting the defined threshold.
• the threshold may be set to the angular rate of +/-5 deg/s in the illustration of Figure 10a so that the steering operation may be determined by the angular rate exceeding 5 deg/s in the positive or negative values.
• the measured angular information is processed as described above with the process of Figure 3, where a coordinate transformation is performed between the coordinate system of the wheel and the vehicle's coordinate system.
• Figure 10b illustrates angular infornnation obtained from the inertial unit illustrated in Figure 10a after transformation to the vehicle's coordinate system. Peaks in the angular information may be used to determine both the steering operation and the direction of the steering operation.
• the threshold may be set to the angular rate of +/-5 deg/s in Figure 10b similar to Figure 10a. However, the threshold may be set to both negative and positive angular rates that correspond to different steering directions.
• the angular information illustrated in Figure 10b is obtained by filtering and applying bias reduction to the angular information in the vehicle's coordinate system. In this way the data is smoothened to facilitate accurate detection of the steering operation and direction.
• bias reduction may be observed from the angular rates on the time axis between values 260 to 280 illustrated in Figure s 10a and 10b.
• the angular rates are biased and the angular rates are mostly below 0.
• the bias is reduced and the filtered angular rate is very small indicating that the vehicle is driving straight.
• the filtering applied to the angular information is averaging over time.
• other filtering functions may be used.
• the averaging applied to the angular information over one full rotation of the wheel has resulted in the rectangular shape of the curve in Figure 10b.
• the filtered angular information provides that the threshold may be set also to smaller values than +/-5 deg/s, for example to 2.5 deg/s or less in the present example.
• a threshold may be defined for the measured angular information.
• the angular information may be the angular information obtained from the inertial unit or the angular information obtained from the inertial unit after processing, for example by coordinate transformation, bias reduction and filtering.
• the threshold may correspond to a steering direction of the vehicle, whereby different steering directions may have different thresholds for the angular information. Accordingly, the steering direction of the vehicle may be determined 906 on the basis of the angular information meeting a threshold for the steering direction. On the other hand a steering operation of the vehicle may be observed by a single threshold.
• the determined steering direction of the vehicle may be used to control when an indicator of the apparatus attached to the wheel is set. Accordingly, when the threshold for the angular information in a specific steering direction is met, the indicator may be set 912.
• the vehicle comprises a plurality of wheels that each are attached an apparatus that includes an inertial unit and an indicator, for example the apparatus of Figure 2. At least part of the indicators may be directed towards different steering directions.
• the indicators may be attached to the wheels according to Figure 6a, whereby the wheels may be arranged on opposite sides of the vehicle with respect to the steering direction according to the illustration of Figure 7.
• indicators in the wheels of the vehicle may be set differently on the basis of the steering direction of the vehicle.
• the steering direction may be determined on the basis of the angular information meeting a threshold for the steering direction.
• Different settings may be defined for the indicators depending on, whether the steering direction is determined that correspond to the direction of the indicator.
• At least one setting for the indicator may be defined that correspond to the situation, where the steering direction and the operation direction of the indicator coincide at least substantially.
• At least one setting for the indicator may be defined that correspond to the situation, where the steering direction and the operation direction of the indicator do not substantially coincide. Accordingly, in this way the measured angular information may be used to set the indicators operating in the steering direction and the indicators that do not operate in the steering direction.
• the angular information obtained from the inertial unit attached to the wheel is used to determine wear of the wheel.
• the angular information may be used to calculate centripetal acceleration of the wheel.
• the centripetal acceleration indicates friction between the wheel and the surface the wheel is being driven. The increased friction causes the wheel to wear.
• wheels have a wear surface that has thickness that wears as the wheel is used.
• the centripetal acceleration may therefore indicate wear of the wheel.
• the centripetal acceleration is particularly preferable as a measurement of the wear of the wheel, since it indicates friction that prevents the vehicle from pushing in the corners or sliding of the rear, which are typically critical situations and may end up in impacts in the sides of the vehicle.
• the centripetal acceleration is determined in the vehicle's coordinate system to obtain acceleration information from all the wheels of the vehicle in the same coordinate system.
• the acceleration may be obtained by
• ⁇ ,-ot is the angular rate of the wheel in the vehicles coordinate system
• V is the is the wheel speed and a z is the acceleration of the wheel in the vehicles coordinate system 402 Z-direction.
• the angular rate ⁇ ⁇ ⁇ may be obtained by
• C V B is a direction cosine matrix between the vehicle's coordinate system and the wheel's coordinate system as a function of the vehicle phase angle 3 ⁇ 4! , (phi).
• [p q 0] is the gyroscope scalar vector defined by (5). Then by using (10) and adding time t, we get pit) €m ⁇ it) j— qi t) sin(0(i) )
• the V in equation (9) may be obtained by: where R is the wheel radius and ⁇ is the first time derivative of the phase angle of the wheel. Accordingly, the wheel speed defines the speed of the wheel hub with respect to the surface, where the wheel is progressing by rotational movement, when the vehicle is driven. To observe the phase angle switched or magnet may be used to determine the time it takes for a full rotation of the wheel and obtain ⁇ ( ⁇ ), for example by estimating using interpolation.
• Wear of a wheel may be determined 908 on the basis of the acceleration information in various ways.
• a threshold may be set for a cumulative value of acceleration measured from the wheel.
• the cumulative value may be updated by acceleration information obtained for the duration the whole duration the wheel is being used. Then the cumulative value may be compared to the threshold and the wheel may be determined to be worn when the threshold is met.
• the method may proceed to 912, to set an indicator similar to explained above for the determining of the steering operation.
• a threshold may be defined for the acceleration information and a cumulative value of the acceleration information is calculated from the acceleration values that meet the threshold. Then the cumulated acceleration information may be compared with a threshold defined for the cumulative acceleration information. When the threshold for the cumulative acceleration information is met, the tire may be determined to be worn.
• the time may be measured by revolutions of the wheel, whereby the effective operation time of the wheel may be obtained.
• the cumulative values of the acceleration information may be implemented by a counter that is updated when the threshold is met.
• Lateral sliding of the wheel may be determined 910 on the basis of the centripetal acceleration information in the vehicle's coordinate system.
• centripetal acceleration for a wheel is very low, for example substantially 0 or a negative value, it may be determined that the wheel is in lateral sliding. This determination may be supported by further determining 1006 steering operation of the vehicle.
• the threshold is met the method may proceed to 912, to set an indicator similar to explained above for the determining of the steering operation.
• lateral sliding of the vehicle having a plurality of wheels may be determined by comparing centripetal acceleration values of the wheels.
• the lateral sliding may be determined on the basis of a difference of the accelerations calculated for the wheel in the steering direction.
• the centripetal acceleration information obtained from the wheels on the inner curb side of the vehicle may be compared with each other. If the difference of the centripetal accelerations is greater than a threshold, the lateral sliding of the vehicle may be determined. Lateral sliding may be observed in four-wheeled road vehicles, for example in cars, by pushing of the vehicle in corners or by sliding of the rear of the vehicle. In pushing, both the font wheels, or in sliding, both the rear wheels, have substantially zero or negative centripetal acceleration.
• the method of Figure 9 may be performed by a stability control system in a vehicle. Then, the determined steering operation 906, wheel wear 908 and the lateral sliding 910 may set 912 an indicator in the user interface of the stability control system. In this way, indications may be provided to the environment of the vehicle and to the user of the vehicle.
• the process of Figure 9 may be performed by the apparatus attached to the wheel or by the stability control system, or different steps of the method may be performed in the apparatus attached to the wheel and the stability control system.
• the stability control system may obtain the angular information from the wheels by the arrangement of Figure 8, for example.
• the stability control system and the apparatus attached to the wheel may include indicators as described above. It is also possible to set indicators in both the apparatus attached to the wheel and the stability control system. In this way both the person, e.g. the driver, observing the stability control system and the environment may be informed about the turning of the vehicle.
• steps/points, signaling messages and related functions described above in Figures 3 and 9 are in no absolute chronological order, and some of the steps/points may be performed simultaneously or in an order differing from the given one. Other functions may also be executed between the steps/points or within the steps/points and other signaling messages sent between the illustrated messages. Some of the steps/points or part of the steps/points can also be left out or replaced by a corresponding step/point or part of the step/point.
• the apparatus carrying out the method described by means of Figure 3 or 10 may be implemented within one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, digitally enhanced circuits, other electronic units designed to perform the functions described herein, or a combination thereof.
• ASICs application specific integrated circuits
• DSPs digital signal processors
• DSPDs digital signal processing devices
• PLDs programmable logic devices
• FPGAs field programmable gate arrays
• processors controllers, micro-controllers, microprocessors, digitally enhanced circuits, other electronic units designed to perform the functions described herein, or a combination thereof.
• the implementation may be carried out through modules of at least one chip set (e.g., procedures, functions, and so on) that perform the functions described herein.
• the software codes may be stored in a
• the above described embodiments involve a method by an apparatus comprising an inertial unit for being attached to a wheel of a vehicle, said inertial unit arranged to detect directions at plane defined by circumference of the wheel for providing angular information and a controller coupled to the inertial unit for processing the angular information, wherein the method comprising: measuring angular information, determining a steering operation of the vehicle on the basis of the measurement results of the angular information.
• the apparatus comprises an indicator coupled to the controller, wherein the indicator is for emitting a signal indicating a steering operation of the vehicle to a steering direction, wherein the method comprises defining a threshold for the measured angular information corresponding to the steering direction of the vehicle, determining when the angular information meets the threshold; and set the indicator, when the threshold is met.
• the apparatus comprises a plurality of indicators corresponding to a plurality of steering directions.
• each of the indicators is associated with a steering direction and a threshold for the measured angular information
• the method comprises defining a first setting for the indicators, when a threshold for the angular information is met, and defining a second setting for indicators, when a threshold for the angular information is not met; and setting the indicators according to the first setting and the second setting on the basis of the measured angular information.
• the indicator comprises an illuminator, for example a lamp, light emitting diode, or a radio frequency transmitter, said radio frequency transmitter being preferable a directional radio frequency transmitter.
• the indicator is arranged to emit a signal outwards from the wheel.
• the method comprises measuring centripetal acceleration for the wheel for determining wear of the wheel.
• the method comprises determining centripetal acceleration for the wheel on the basis of the angular information.
• the method comprises defining centripetal acceleration for the vehicle on the basis of the measured angular information; and determining lateral sliding of the vehicle on the basis the centripetal acceleration.
• the method comprises determining centripetal acceleration for the wheel on the basis of the angular information; measuring the centripetal acceleration over time; and determining wear of the wheel on the basis of the measurements of the centripetal acceleration.
• the method comprises obtaining data on a tilting angle of a rotatable part of a vehicle and/or obtaining data on rotations, obtaining data on a tilting angle of a rotatable part of a vehicle and obtaining data on angular information, and processing the data by using the tilting angle and/or the detected rotations for at least one coordinate system transformation and by using rotation of the rotatable part for compensating gyroscope bias for compensating inaccuracy of the angular information.
• the at least one coordinate system transformation is carried out by using at least one direction cosine matrix.
• the direction cosine matrix is estimated by normalizing accelerometer readings or by using data obtained by the at least one gyroscope.
• an angle of phase difference, covered distance and/or covered distance in a predetermined period of time are estimated by the data processing.
• the data processing comprises updating location information of the vehicle by using change in covered distance in a predetermined period of time in relation to selected axes transferred to a selected coordinate system.
• a moment of completing a full rotation is estimated or detected and data with regard to one rotation is gathered from the at least one gyroscope.
• the method comprises vehicle positioning using the coordinate system transformation.
• the angular information is obtained by a gyroscope arranged to detect directions in a coordinate system arranged at the rim level of the wheel.
• the at least one coordinate system transformation is carried out on the basis of the angular information and tilting angle and/or the detected rotations.
• full 360° rotations of the rotatable part are detected for compensating the gyroscope bias.
• the above described embodiments involve an apparatus comprising an inertial unit for being attached to a wheel of a vehicle, said inertial unit arranged to detect directions at plane defined by circumference of the wheel for providing angular information for positioning, and a controller coupled to the inertial unit for processing the angular information, wherein the apparatus comprises means to perform the steps of a method according to an aspect.
• the inertial unit comprises: at least one acceleration sensor and/or at least one magnetometer arranged to detect a tilting angle of the wheel, and/or at least one counter device arranged to detect rotations of the wheel, and at least one gyroscope arranged to detect directions at a rim level of the wheel for providing angular information for positioning.
• the counter device comprises a brake disc or a brake block and a magnet or switch for counting full revolutions.
• the apparatus comprises a dynamo for obtaining energy from a rotation of the wheel.
• the apparatus comprises two gyroscopes with about 90° angular spacing.
• a moment of completing a full rotation is estimated or detected and data with regard to one rotation is gathered from the at least one gyroscope.
• the inertial unit is for vehicle positioning using a coordinate system transformation.
• the at least one gyroscope is arranged to detect directions in a coordinate system arranged at the rim level of the wheel.
• the apparatus comprises means for processing data, the data comprising the detected tilting angle and/or detected rotations and the angular information, by using the tilting angle and/or the detected rotations for at least one coordinate system transformation and by using rotation of the wheel for compensating gyroscope bias for compensating inaccuracy of the angular information.
• the at least one coordinate system transformation is carried out by using at least one direction cosine matrix.
• the direction cosine matrix is estimated by normalizing accelerometer readings or by using data obtained by the at least one gyroscope.
• the apparatus comprises two gyroscopes with about 90° angular spacing.
• an angle of phase difference, covered distance and/or covered distance in a predetermined period of time are estimated by the data processing.
• the data processing comprises updating location information of the vehicle by using change in covered distance in a predetermined period of time in relation to selected axes transferred to a selected coordinate system.
• a moment of completing a full rotation is estimated or detected and data with regard to one rotation is gathered from the at least one gyroscope.
• the apparatus is for vehicle positioning.
• the at least one coordinate system transformation is carried out on the basis of the angular information and tilting angle and/or the detected rotations.
• the above described embodiments involve an apparatus comprising at least one processor, and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform the steps of a method according to an aspect.
• the above described embodiments involve a system comprising one or more apparatuses according to an aspect.
• the above described embodiments involve a computer program product comprising executable code that when executed, cause execution of functions of a method according to an aspect.

Landscapes

• Engineering & Computer Science (AREA)
• Radar, Positioning & Navigation (AREA)
• Remote Sensing (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Automation & Control Theory (AREA)
• Mechanical Engineering (AREA)
• Transportation (AREA)
• Mathematical Physics (AREA)
• Navigation (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=52778304

Family Applications (1)

Country Status (2)

Cited By (3)

Citations (5)

• 2013
  • 2013-10-03 FI FI20135991A patent/FI125167B/sv active IP Right Grant
• 2014
  • 2014-09-30 WO PCT/FI2014/050744 patent/WO2015049418A1/en active Application Filing

Patent Citations (5)

Also Published As

Similar Documents

Legal Events