United States Patent (19) 11 3,936,712 Gerber et al. 45 Feb. 3, 1976 54) INTERACTIVE GRAPHIC SYSTEM 57 ABSTRACT 75 Inventors: Heinz Joseph Gerber, West An interactive graphics system in which plotting, digi Hartford; David J. Logan, tizing and other related capabilities are performed is Glastonbury; Leonard G. Rich, West described in which complex graphics may be gener Hartford, all of Conn. ated, edited and developed at a plurality of terminals, 73) Assignee: The Gerber Scientific Instrument independently, with a minimum of hardware and in Company, South Windsor, Conn. which precision control of the motion of a plotting table at each location is achieved in response to sim 22 Filed: July 9, 1973 plified input commands. Additionally, a novel floating 21 Appl. No.: 377,769 cursor is described by which an operator may control the motion of the carriages of a plotting table or other Related U.S. Application Data positioning system actuated during plotting on the ta 63 Continuation-in-part of Ser. No. 353,115, April 20, ble, and digitize various coordinate locations with cor 1973, abandoned. responding storage in a central computer of such loca tions, all by manually positioning the cursor at the de 52) U.S. Cl. ................ 3181568; 318/576; 318/.577; sired locations. The floating cursor is connected with 3 18/628 an energy sensor and both the cursor and the sensor (51) Int. Cl. ........................................... G05b 19142 are mechanically movable relative to or independently 58) Field of Search ............ 3181568,576, 628,577 of the carriage. An energy generator is fixedly con nected to the carriage and is directed toward the sen 56) References Cited sor so that relative movement of the cursor and car UNITED STATES PATENTS riage can be detected by the sensor. The carriage is 3,258,776 6/1966 Boyle et al...................... 3 18/592 X then made to move with the cursor in response to sig 3,391,392 7/1968 Doyle................................ 3181568 nals generated from the energy sensor. Thus, the cur 3,398,452 8/1968 Little ................. ... 3181569 X sor floats with respect to the carriage, which precisely 3,693,066 9/1972 Friedman et al................ 3181628 X follows the cursor over a plotting surface and which 3,725,760 4/1973 Bailey................................. 3181568 carriage contains various devices for drafting or other 3,727,119 4/1973 Stanley et al....................... 3181568 operations on material located on the plotting surface. 3,750, 186 7/1973 Sakamoto....................... 3181568 X 3,774,098 11/1973 Moss................................... 3181568 Primary Examiner-B. Dobeck Attorney, Agent, or Firm-McCormick, Paulding & 38 Claims, 10 Drawing Figures Huber f5. ---- O O a ---4. - - - AAS/6A/ 5747/ow % /AWA/7 Ac/70M/47C Aov7a A AS/M/ S7470MW S74772ay U.S. Patent February 3, 1976 Sheet 1 of 6 3,936,712 . AAS/6A/ 574 7/ow //WA/7 24saw da5/6AW S747/2M/ SVa//0MW - each O eases ors s WWAV7 66 x- wa Zaw crow/6a 34 la -------- - - - - y Saavo Oly- wa aow crow 7aa c af7ya 7 -- a--- key H42): O 32 CO/MAC/72A s aocassoa. AAS/6M/ 57247/02/V - U.S. Patent February 3, 1976 Sheet 5 of 6 3,936,712 CN O O) V NO 9 5. V- V V CO NO s e oS.S.S. o o s S. s S. 5 s 9 33 HS U.S. Patent February 3, 1976 Sheet 6 of 6 3,936,712 3,936,712 1. 2 INTERACTIVE GRAPHIC SYSTEM SUMMARY OF THE INVENTION An interactive graphics system and a novel cursor CROSS REFERENCE TO RELATED therefore is described in which a plurality of graphic APPLICATIONS design stations under the control of a central computer This application is a continuation-in-part of copend generate a variety of artwork. At each design station, ing application Ser. No. 353,115, filed Apr. 20, 1973, either a "floating cursor' or an electronically gener now abandoned, entitled Interactive Graphics System, ated cursor is utilized by a station operator to digitize and having the same assignee. and plot complex data with a minimum of hardware. In 10 the "floating cursor' arrangement, a cursor is mechani BACKGROUND OF THE INVENTION cally connected to a sensor or detector which is respon This invention relates to an interactive design or sive to impinging energy from a source or energy gener graphics system in conjunction with which a variety of ator mounted on a carriage assembly movable in at terminal devices may be operated at a plurality of loca least two coordinate directions in a plane generally tions to produce precision mechanical, manufacturing 15 parallel to the material upon which artwork is to be or architectural drawings from rough sketches, photo generated. The cursor is movable mechanically inde grammetric plans, schematics, printed and integrated pendently of the carriage for maximum operator effi circuit artwork masters, and other related graphics. ciency, and positioning signals generated in response to An interactive graphics system is a system capable of the sensor output are utilized to position the carriage, performing some or all of the above functions in which 20 upon which a variety of writing instruments are the man-machine interface is utilized to maximize the mounted. The cursor is preferably touch sensitive in capabilities of both to produce an end product that, order that the system is actuated to enable carriage because of the synergistic maximization of capabilities, motion oniy in response to operator control such that is in effect superior to that which could be produced the carriage “follows' the floating cursor and locks either by a computer system alone or by an operator 25 into place when the cursor is released. The carriage alone. While interactive graphics systems as such are itself is adapted for motion in the X and Y coordinate existent in the prior art, a persistent problem has been directions by a timing belt arrangement controlled by the complexity of software and hardware required to servo motors driven by control signals generated by the convert the human input into useful computer data 30 local computer in response to information computed from which graphics can be generated, and in convert from the sensed cursor position. Both position and ing the computer output into simplified data from velocity feedback are derived from resolvers and ta which an operator can derive additional system input, chometers which form a portion of the servo system. all in a substantially continuous operation. The control signals are in the form of motor pulses at a A problem of the prior art in such systems is in 35 frequency proportional to the cursor positional error achieving immediate system plotback from data de with respect to the carriage mounted energy source. rived from raw material such as rough sketches. In such In another embodiment of the invention, a mechani systems, data must first be digitized, or converted from cal stylus is utilized to position an electronic cursor on the sketch to digital coordinate locations and then the face of a storage cathode ray tube, which enables subjected to various time consuming operations before 40 an operator to control the system operation with a it can later be plotted as a drawing. In the present sys simple movable control. tem, an operator manually positions a mechanical cur sor at selected locations on, for example, a rough BRIEF DESCRIPTION OF THE DRAWINGS sketch. The cursor serves to control the movement of a Further advantages of the invention will become drafting carriage which "follows' the cursor around 45 apparent from the following specification taken in con the plotting surface and which is electronically con nection with the accompanying drawings wherein like trolled by computer commands which in turn are de reference characters identify elements of like function rived in part from the cursor position. Such an arrange throughout the different views thereof, and wherein in ment permits an operator, merely by moving the cursor several of the views double lines indicate data flow. to different locations to digitize for later plotting com 50 FIG. 1 is a simplified block diagram of an interactive plex drawings from rough sketches. The system soft graphics system embodying the present invention. ware enables and controls storage, retrieval, carriage FIG. 2 is a block diagram of an interactive graphics positioning and reproduction of all graphic and alpha system in accordance with the present invention. numeric information by the system under operator FIG. 3 is a block diagram of a cursor control system control, and incorporates the requisite programs for 55 incorporating floating cursor in accordance with the communicating with a data base and the various pe present invention. ripheral equipment, with software data decoding being FIG. 4 is a simplified isometric view of a four quad used in place of hardware decoding. rant detector as employed in the present invention. In another embodiment of the invention, an elec FIG. 5 is a block diagram of certain circuitry which is tronic cursor generated by a simple mechanical stylus 60 employed in the present invention. arrangement on the face of a cathode ray tube may be FIG. 6 is a block diagram of an interactive graphic substituted for the mechanical cursor on the plotting system in accordance with the present invention. table, or used in combination therewith. In prior art FIG. 7A is a plan view of a plotting table of the type systems, sophisticated training is required to operate utilized in the present invention. systems of the prior art, whereas the present system 65 FIG. 7B is a side elevation view of the plotting table configuration allows relatively untrained personnel to of FIG.