United States Patent
`Smith, I11 et al.
`
`5,043,646
`[ i 11 Patent Number:
`[45] Date of Patent: Aug. 27, 1991
`
`[75]
`
`[54] REMOTE CONTROL DIRECTION
`SELECTING SYSTEM
`Inventors: Jay Smith, 111; Daniel J. Schmieder,
`both of Los Angeles, Calif.
`[73] Assignee: Smith Engineering, Culver City,
`Calif.
`[21] Appl. No.: 517,368
`[22] Filed:
`May 1, 1990
`Int. C1.5 ......................... H04Q 7/02; G05D 3/10
`[51]
`[52] U.S. C1. ...................................... 318/581; 318116;
`318/587
`[58] Fieldofsearch ................. 318116, 580, 583, 581,
`318/584, 587, 588
`
`1561
`
`References Cited
`U.S. P A T E N T DOCUMENTS
`2,419,970 5/1947 R o e e t a l . .............................. 318/16
`2,490,768 12/1949 Althouse et al. ..................... 318/16
`1/1951 Rothschild .......................... 342/398
`2,539,482
`Litchford ........................ 318/581 X
`2,705,793 4/1955
`2,745,614 5/1956 Bennett et al. ...................... 244/184
`2,826,380 3/1958 Ketchledge ......................... 2 4 4 1 8 4
`2,866,930 12/1958 Russell .................................. 318116
`
`Primrlty Examiner-Bentsu R o
`Attorney, Agent, or Firm-Price, Gess & Ubell
`
`ABSTRACT
`C571
`A remote control transmittedreceiver system wherein
`an absolute direction command may be issued by the
`transmitter and acted upon by the receiver. The trans-
`mitter and receiver both include a common reference
`direction so that an absolute direction command (i.e.,
`relative to the common reference direction) may be
`issued and acted upon. In a preferred embodiment, the
`transmitter operates in accordance with an internal
`compass signal so that an absolute direction command
`relative to magnetic North can be generated by the
`transmitter. The receiver also functions in accordance
`with an internal compass signal so that an absolute di-
`rection command transmitted to the receiver can be
`effected. The transmitter and receiver may be micro-
`processor controlled, and the internal compass signal
`may be generated with an electronic flux gate compass.
`The invention may be used in place of the conventional
`remote control systems that are used with hand-held
`transmitters and hobby vehicles.
`
`9 Claims, 4 Drawing Sheets
`
`RECEIVER
`
`11L
`
`.'IN
`FLUX GATE
`COMPASS
`
`cos e
`
`110
`
`112
`
`REV
`
`ILL
`RIGHT (
`1 S2
`
`LEFT
`
`MOTOR
`CONTROL
`CIRCUITRY
`
`lL5
`
`STEERING
`CONTROL
`CIRCUITRY
`
`140
`
`1L7
`1L6
`STEERING /
`ELECTRO-
`MAGNET
`
`Parrot Ex. 1002
`
`

`

`U.S. Patent
`
`Aug. 27, 1991
`
`Sheet 1 of 4
`
`5,043,646
`
`FIG. 1
`PRIOR ART
`
`FIG. 2a
`
`FIG. 2b
`
`

`

`100\
`
`FORWARD
`
`TURBO
`REVERSE
`
`'28
`
`30
`
`32
`
`I
`I
`
`
`
`180
`
`125
`
`JOYSTICK
`
`26
`
`FIG. 3
`F
`
`31.
`
`r
`
`36
`
`-
`TRANSMITTER
`
`1
`RAD I0
`RADIO
`TRANSMITTER
`
`38
`J 38
`
`
`
`mama'S'fl
`
`
`
`1661‘Lz'3nv
`
`'1730Zwells
`
`9179‘9170‘9
`
`14
`
`SING
`
`FLUX GATE
`
`COMPASS
`
`10
`
`
`
`765/.3210
`
`
`
`
`
`p CONTROLLER
`
`21.
`
`13
`
`

`

`FIG. 5
`
`(SYNC BYTE)
`BYTE 2
`BYTE 1,
`BYTE 3
`BYTE 1
`-0-0
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`
`A uu
`
`A
`
`COMMANDED ANGLE 8 BI T CHECKSUM
`[BYTE 2 + BYTE 31
`(0- 359)
`
`1 0 FORWARD
`
`0 1 REVERSE
`0 0 TURBO FORWARD
`1 1 STOP
`
`0 JOYSTICK LEVER DEPRESSED
`1 JOYSTICK INACTIVE
`
`

`

`U.S. Patent
`US. Patent
`
`Aug. 27, 1991
`Aug. 27, 1991
`
`Sheet 4 of 4
`Sheet 4 of 4
`
`5,043,646
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`

`1
`
`5,043,646
`
`2
`so that the user can rapidly engage in the mental acro-
`batics necessary to steer the vehicle.
`
`REMOTE CONTROL DIRECTION SELECTING
`SYSTEM
`
`5
`
`SUMMARY O F T H E INVENTION
`BACKGROUND O F THE INVENTION
`It is an object of the present invention to provide a
`remote control transmitting device that is capable of
`1. Field of the Invention
`transmitting a direction control signal that contains
`~h~ present invention relates generally to remote
`direction control information relative to an external
`control systems where a user selects and transmits a
`reference
`direction control signal from a remote control transmit-
`ter to a remotely controlled device. More particularly, lo
`It is a further object of the present invention to pro-
`vide a remotely controlled device that includes a direc-
`the present invention relates to an improved remote
`tion related feature, the direction related feature re-
`control system where the user may select a desired
`sponding to a direction control signal that contains
`direction relative to an external reference direction
`direction control infomIati0n relative to an external
`without considering the orientation of the remote con-
`trol transmitter or the remotely controlled device rela- l5 reference direction;
`It is a further object of the present invention to pro-
`tive to the external reference direction.
`vide an improved remote control system wherein a
`2. Description of .the Prior Art
`direction control command takes effect relative to the
`There are many known varieties of remote control
`systems. Probably the first to come to mind are those 20 position of a remotely controlled vehicle, but without
`regard to the direction that the vehicle is facing; and
`used with hobby vehicle systems such as remote control
`It is a further object of the present invention to pro-
`planes, boats, cars, etc.
`vide an improved remote control hobby vehicle system
`A typical prior art hobby vehicle system consists of a
`that includes a remote control vehicle and a remote
`remote control transmitter that includes a user-operated
`means for selec:jsg either "left" or "right" and for 25 control transmitting device where the user is capable of
`transmitting a direction control signal in response to the
`selecting an absolute direction command and the re-
`user selection and 'a remotely controlled vehicle (car,
`mote control vehicle is capable of responding thereto.
`The present invention achieves the above objects by
`boat, plane, etc.) that responds to the transmitted direc-
`tion control signal. For example, a radio controlled car
`providing a remote control transmitting device that
`is comprised of a car that may be commanded to turn 30 comprises a first measuring means for measuring the
`left or right and a remote control transmitter from
`orientation of the remote control transmitting device
`which the user may select and transmit left or right
`relative to an external reference direction, a second
`direction control commands. A typical direction select-
`direction measuring means for measuring a user-
`ing means consists of a joystick that may be moved
`selected direction relative to the remote control trans-
`either left or right relative to the remote control device. 35 mitting device, and a processing means for generating a
`Ordinarily, the user must continuously hold the joystick
`direction control signal based on first and second com-
`in the selected direction during the entire time that the
`ponent direction signals output by the first and second
`direction measuring means. The present invention fur-
`vehicle is turning and then release the joystick to end
`the turn.
`ther includes a remotely controlled device that includes
`The prior art remote control systems are burdened by 40 a third measuring means for measuring the orientation
`the fact that the resulting direction of the vehicle is
`of the remotely controlled device relative to the exter-
`based on factors that are constantly changing relative to
`nal reference direction and a means for controlling a
`the user and the remote control transmitter, namely the
`direction related feature of the remotely controlled
`position and direction of the vehicle. Since the position
`device based upon a component signal output by the
`and direction of the remotely controlled vehicle are 45 third measuring means and a control signal received
`constantly varying relative to the user, the resulting
`from a remote control transmitting device.
`The features of the present invention which are be-
`direction of the vehicle, relative to the user, is also
`constantly varying.
`lieved to be novel are set forth with particularity in the
`Given a remote control car, for example, if a user
`appended claims. The present invention, both as to its
`selects and transmits a "left" or "right" direction con- 50 organization and manner of operation, together with
`trol signal when the car is travelling radially away from
`further objects and advantages thereof, may best be
`the user, the resulting direction of the car, relative to
`understood by referencing the following description in
`the user, will correspond to the transmitted direction
`conjunction with the accompanying drawings.
`control signal. More specifically, if a "left" command is
`transmitted, the car will travel left relative to its direc- 55
`tion and position and also relative to the user.
`However, if a "left" or "right" direction control
`signal is transmitted to the car when it is travelling
`radially towards the user, the resulting direction of the
`car, relative to the user, is inversely related to the trans- 60
`mitted direction control signal. Under these circum-
`stances, if a "left" command is transmitted, the car will
`travel left relative to its direction and position but will
`travel right relative to the user.
`It can be seen from the above description that the 65
`user with an ordinary radio control system must always
`be conscious of the position of the vehicle and the direc-
`tion that it is travelling, both before and during a turn,
`
`BRIEF DESCRIPTION O F THE DRAWINGS
`FIG. 1 a schematic representation of a prior art radio
`control vehicle system where a left or right direction
`control command transmitted by the remote control
`device is effectuated as a left or right direction control
`command relative to the position of the car and the
`direction in which the car is currently facing;
`FIGS. 2u and 26 are schematic representations of a
`radio controlled vehicle system according to the pres-
`ent invention wherein a user-selected direction D is
`treated as an absolute direction command, independent
`of the orientation of the remote control transmitting
`device, the vehicle altering the current direction it is
`facing to travel in the selected direction;
`
`

`

`5,043,646
`
`39
`
`3
`4
`FIG. 3 is a schematic block diagram of a remote
`single hand-held housing like that schematically shown
`control transmitting device according to the present
`in FIG. 2a.
`invention;
`The primary purpose of the present invention is to
`FIG. 4 is a schematic block diagram of a remote
`allow the user to control the direction of the the car 200
`control receiving device according to the present in- 5 by moving the shaft 26j of the joystick 26 towards any
`vention; and
`desired absolute direction. For clarity, all subsequent
`FIG. 5 is a bit map of a digital command sequence
`directions stated in degrees are to be taken relative to
`transmitted by the remote control transmitting device.
`magnetic North. For example, East will be stated as 90"
`and West will be stated as 270".
`DESCRIPTION O F T H E P R E F E R R E D
`10 Ordinarily, a user of the present invention would
`EMBODIMENTS
`select a desired direction without knowing or even
`The following description is provided to enable any
`being concerned with how the desired direction relates
`person skilled in the art to make and use the invention
`M~~~ specifically, the user would
`to magnetic ~ ~ ~ t h .
`
`and sets forth the best modes contemplated by the in-
`simply select a direction in which he or she wants the
`ventor of carrying out his invention. Various modifica- 15 car to travel as if he or she were standing at the point
`tions, however, will remain readily apparent to those
`where the car is currently located.
`skilled in the art, since the generic principles of the
`still to FIG. 3, it can be seen that sine and
`~
`~
`~
`~
`f
`~
`present invention have been defined herein specifically
`cosine voltages 14, 12 are available as outputs from the
`A suitable flux gate
`is the
`gate
`to provide an improved remote control direction select-
`ing system.
`20 Micronta Automotive Electronic Compass sold by .
`The preferred embodiment of this invention is di-
`Radio Shack, Catalog No. 63-641. A detailed discussion
`rected towards a remote control system that includes a
`of the operational details of the flux gate compnss will
`hand-held remote control transmitter 100 and a small
`be omitted because such devices are well known and
`car 200 (see
`2a and 2b)'
`a material
`their internal operation does not
`The remote control transmitter 100 transmits control 25 portion of this invention except as herein explained.
`signals in response to various user-manipulated control
`Suffice it to say that the magnitude of the voltages
`switches. Typical control switches include a forward-
`present on the sine and cosine outputs 14,12 correspond
`/reverse switch, a "turbo" switch for temporarily in-
`to the sine and cosine of the earth's magnetic field, and
`creased speed, and a direction control switch such as a
`joystick 26j. The remotely controlled car 200 is typi- 30 that the data necessary to interpret the orientation of the
`cally controlled with left/right and forward/reverse
`flux gate
`and the
`transmitter
`100 is obtained by determining the ratio of the sine and
`signals that are activated in accordance with control
`cosine
`this purpose, the sine and cosine
`signals transmitted by the remote control transmitter.
`voltages 14, 12 are provided to the microcontroller 24
`the prior art remote control systems, the user is
`35 via an 8-bit successive approximation A / D converter
`limited to only a left and a right direction control.
`13. As shown in
`converter l 3 is
`the A'D
`shown in FIG. 1, a prior art remote control transmitter
`~ r i s e d of two comparators 16, 18. The sine and cosine
`60 might have a joystick shaft 62 that can be moved left
`or right or, alternatively, separate left and right direc-
`voltages 14, 12 are provided to the noninverting inputs
`l 8 and an R/2R
`tion control buttons (not shown). The disadvantage of
`the
`DAC
`such a ;emote control transmitter 60 is that a user's left 40 ladder circuit 22 provides a variable analog reference
`or right selection is effectuated relative to the position
`voltage to the inverting inputs of the comparators. The
`of the car and the direction (d) that the car is facing
`microcontro11er is programmed to determine the magni-
`tude of the sine and cosine voltage 14, 12 by taking the
`rather than relative to the user or some external refer-
`R/2R D A C 22 through a voltage progression
`ence direction. Thus, the user must first mentally con-
`sider what direction the car is travelling before select- 45 while simultaneo'Jsl~ monitoring the outputs 17, 19 of
`the two comparators.
`ing left or right. Moreover, the user must constantly
`The microcontroller determines the orientation of the
`consider the relationship between the direction of the
`flux compass by first dividing the absolute value of the
`car and the selected direction throughout the entire turn
`sine voltage 14 by the absolute value of the cosine volt-
`and must release the joystick shaft 62 as soon as the car
`50 age 12 to obtain a tangent voltage, and by then using the
`has turned into the desired direction.
`tangent voltage as an index into an arctangent look-up
`The present invention offers a remote control system
`table of 256 entries ranging from 0 to 90 degrees. The
`that transmits an absolute direction command (relative
`angle found in the arctangent look-up table is then ex-
`to magnetic north) so that the user can control the car
`panded into one of four quadrants by taking into ac-
`without being concerned about the direction that the
`car is travelling prior to or while manipulating the di- 55 count the relative signs of the sine and cosine voltages
`14, 12. The resultant angle represents the orientation of
`rection controls, without being concerned about the
`orientation of the remote control transmitter 100, and
`the remote control transmitter 100 and the flux gate
`without having to release the joystick shaft at the pre-
`compass from between 0 and 359 degrees relative to
`cise moment that the car has achieved the desired direc-
`magnetic North.
`The joystick 26 is an eight position 4-microswitch
`tion.
`FIG. 3 is a schematic block diagram of a preferred
`joystick. A suitable joystick is produced by Archer
`remote control transmitter 100 according to the present
`under the trade name Super-Deluxe Competition Joy-
`invention. The remote control transmitter is comprised
`stick, Catalog No. 270-1703. The orientation of the
`of a microcontroller 24 that is provided with inputs
`joystick shaft 26j relative to the remote control trans-
`from three momentary pushbutton control switches 28, 65 mitter 100 is communicated to the microcontroller 24
`30,32, an 8-position joystick 26, and a flux gate compass
`via four inputs lines labelled O", 9O0, 180°, and 270". The
`10 (via an A/D converter 13). All of the components
`four input lines correspond to the joystick's four micro-
`depicted in FIG. 3 would ordinarily be contained in a
`switches and provide a 45-degree resolution in that
`
`60
`
`i
`
`~
`
`,
`
`

`

`either a single or two angularly adjacent microswitches
`sequence is processed. For example, if the car is in mo-
`are closed and communicated to the microcontroller 24.
`tion, and the appropriate Byte 2 indicates that a joystick
`As further shown in FIG. 3, the remote control trans-
`command has been received, then microcontroller 124
`will read the flux gate compass 110 to determine if a
`mitter 100 is also comprised of the following control
`switches: a momentary contact forward control switch 5 turn is required. If a turn is required, microcontroller
`28, a momentary contact turbo control switch 30, and a
`124 will determine which of two possible directions will
`momentary contact reverse control switch 32. In the
`result in the smallest angle of rotation. While the turn is
`preferred embodiment, the forward and reverse control
`in progress, microcontroller 124 will periodically read
`switches 28, 32 are combined in a single momentary
`the flux gate compass 110 to determine when the car
`rocker switch so that their operation is mutually exclu- 10 200 has converged to the commanded angle (direction
`sive. The compass 10 angle is added to the joystick 26
`control signal) contained in byte 3.
`angle to provide an absolute, North-referenced angle to
`The steering of the car is accomplished via a steering
`be transmitted.
`electromagnetic 146 that is controlled by the microcon-
`The user selects a desired direction (D) with the
`troller 124 via left and right control lines 142,144 and a
`joystick shaft 26j ("selected direction") while simulta- 15 steering control circuit 140. The steering control circuit
`neously depressing either the forward 28 or reverse
`140 is interfaced to the steering electromagnet 146 via
`switch 32. The absolute direction ("absolute" meaning
`lines 145 and 147. The precise operation of the steering
`control circuit 140 is not considered material to the
`relative to magnetic North) corresponding to the se-
`lected direction is obtained by summing the orientation
`present invention, and a detailed description thereof is
`of the remote control transmitter 100 relative to mag- 20 therefore omitted.
`netic north with the orientation of the shaft 26j relative
`Motion is imparted to the car 200 with an electric
`to the remote control transmitter 100. For example, if
`motor 157 that is controlled by microcontroller 124 in
`the user moves the joystick shaft 26j so that it is oriented
`accordance with the pertinent portions of the digital
`90' relative to the remote control transmitter 100 r-~hile
`command sequences. The microcontroller 124 commu-
`holding the remote control transmitter 100 so that it is 25 nicates with a motor control circuit 150 via a "turbo"
`oriented 60' from North, the user has selected an abso-
`control line 152, an "FWD" control line 154, and a
`"REV" control line 156. The motor control circuit 150
`lute direction of 150' relative to North. A direction
`is connected to the motor 157 via lines 158 and 159.
`control signal containing information about the absolute
`The direction of the car 200 can be controlled based
`direction relative to magnetic North can then be pro-
`vided to an ordinary radio transmitter 36 via line 34 and 30 upon the orientation of the car 200 relative to magnetic
`then transmitted over antenna 38 to the car 200.
`North and the direction control signal contained in the
`In the preferred embodiment, the direction control
`digital control sequence (Byte 3, FIG. 5), because the
`car 200, like remote control transmitter 100, contains a
`signal is part of a digital command sequence of four
`bytes (see FIG. 5). Byte 1 is a fixed sync byte (AA hex)
`flux gate compass 110 for measuring the orientation of
`that allows the microcontroller 124 in the car 200 to 35 the car 200 relative to magnetic North.
`detect the beginning of a new digital command se-
`Those skilled in the art will appreciate that various
`quence. Byte 2 encodes the forward, turbo-forward,
`adaptations and modifications of the just-described pre-
`and reverse commands and also contains a single bit that
`ferred embodiment can be configured without depart-
`indicates that the joystick handle 26j has been depressed
`ing from the scope and spirit of the invention. For ex-
`to initiate a turn. Byte 3 contains the direction control 40 ample, the present invention is adaptable to other hobby
`vehicles such as planes and boats. Moreover, the pres-
`signal as a digitally encoded number that ranges from 0
`to 359 degrees. The direction control signal corre-
`ent invention is generally applicable to any directional
`sponds to an angle relative to magnetic North. Byte 4 is
`device that is remotely controlled. Therefore, it is to be
`a checksum of bytes 2 and 3, the digital command se-
`understood that, within the scope of the appended
`quence being ignored by the car 200 if it determines that 45 claims, the invention may be practiced other than as
`the checksum does not match (due to radio interference
`specifically described herein.
`or the like).
`What is claimed is:
`Referring now to FIG. 4, the remote control receiver
`1. An improved remote control device that includes a
`200 is comprised of a microcontroller 124, a flux gate
`selecting means for allowing a user to select a user
`compass 110, a radio receiver 136, motor control cir- 50 desired direction and a means for transmitting a direc-
`cuitry 150, and steering control circuitry 140. The flux
`tion control signal in accordance therewith to control a
`gate compass 110 is identical to the flux gate compass 10
`direction related feature of a remotely controlled de-
`used in the radio control transmitter 100. The flux gate
`vice, the improvement comprising:
`compass 110 provides sine and cosine voltage outputs
`a first direction measuring means in the remote con-
`114, 112 that vary based on the orientation of the com- 55
`trol device for measuring the orientation of the
`pass 110 relative to magnetic North. The sine and cosine
`remote control device relative to an external refer-
`voltages 114, 112 are provided to microcontroller 124
`ence direction and for outputting a first component
`via A/D deconverter 113. The operation Of A/D con-
`signal representative thereof;
`verter 113 is identical to that of A/D converter 13,
`a second direction measuring means in the remote
`control device for measuring the user desired di-
`earlier described, and its description will therefore be 60
`omitted.
`rection relative to the remote control device and
`for outputting a second component signal represen-
`The radio receiver 136 receives digital command
`tative thereof; and
`sequences transmitted by the remote control transmitter
`100 via antenna 138. Digital command sequences so
`a processing means for generating the direction con-
`trol signal based on the first component signal and
`received are provided by the radio receiver 136 to the 65
`the second component signal, the direction control
`microcontroller 124 on line 134. Once a command se-
`signal corresponding to the user desired direction
`quence has been received by microcontroller 124, and if
`the checksum test passes, then the digital command
`relative
`to
`the external
`reference direction
`
`

`

`5,043,646
`
`15
`
`8
`7
`the hand-held control device and for outputting
`\vhereby the user selects the user desired direction
`a first component direction signal;
`relative to the external reference direction without
`(c) a second direction measuring means for measur-
`regard to the orientation of the remote control
`ing the orientation of the hand-held control de-
`device.
`vice relative to the external reference direction
`2. The improved remote control device of claim 1
`and for outputting a second component direction
`~vhere the external reference direction is magnetic
`signal;
`north.
`(d) processing means for deriving a direction con-
`3. The improved remote control device of claim 1
`trol signal that corresponds t o the desired direc-
`wherein the first direction measuring means is com- lo
`tion, the direction control signal being derived
`prised of a flux gate magnometer.
`from the first and second component direction
`4. An improved remotely controlled device having a
`signals; and
`direction related feature that is controlled based upon a
`(e) transmitter means for transmitting the direction
`direction control signal received from a remote control
`control signal; and
`(2) a hobby vehicle including:
`device, the improvement comprising:
`measuring means in the remotely controlled device
`(a) receiver means for receiving the direction con-
`for measuring the orientation of the remotely con-
`trol signal;
`trolled device relative to an external reference
`(b) a third direction measuring means for measur-
`ing the orientation of the hobby vehicle relative
`direction and for outputting a component signal
`to the external reference direction and for out- .
`representative
`thereof wherein
`the measuring 20
`putting a third component direction signal;
`means is comprised of a flux gate magnometer; and
`(c) control means for outputting a steering signal
`means for controlling the direction related feature of
`that is proportional to the difference between the
`the remotely controlled device based upon the
`direction control signal and the third component
`direction c c .rol signal and the component signal
`direction signal; and
`whereby the .'irection related feature is controlled 25
`(d) steering means for steering the hobby vehicle in
`in a particular direction relative to the external
`the desired direction in response to the steering
`reference direction based upon the direction con-
`signal.
`trol signal.
`7. The remote control hobby vehicle system of claim
`5. The improved remotely controlled device of claim 30 wherein the selecting means is a
`4 wherein the external reference direction is magnetic
`joystick+
`8. The remote control hobby vehicle system of claim
`north.
`6 wherein the external reference direction is magnetic
`6. A remote control hobby vehicle system compris-
`north.
`ing:
`9. The remote control hobby vehicle system of claim
`(1) a hand-held control device including:
`35 6 wherein the selecting means is a joystick; the first
`(a) selecting means on the hand-held control device
`direction measuring means is comprised of micro-
`for allowing a user to select a desired direction
`switches that are activated by the joystick; and the
`relative to an external reference direction;
`second and third direction measuring means are each
`(b) a first direction measuring means for measuring
`comprised of a flux gate magnometer.
`+
`the orientation of the selecting means relative to 40
`11
`0
`0
`f
`
`