Patent GB-1201602-A (GB)
Title: Sailing simulators for pupil training
Inventor: WADDINGTON ROGOR STRANGE
IPC: G09B9/06
Filed: 1966-05-19
Abstract: 1,201,602. Sailing craft simulator. T.P.I. Ltd. 18 Aug., 1967 [19 May, 1966], No. 22384/66. Heading G4G. In a sailing craft training simulator, the angle of heel is dependent on the speed of simulated wind and its direction relative to the simulator, and on the position of the boom of the simulator relative thereto. Three transducers are operable to generate signals representative of these parameters; two such transducers being interlinked to develop a common signal variable by either transducer independently the effect of the other, and a third transducer being arranged to provide a heel output signal modified by the common signal of the first and second tranducers, in such manner that the heel output signal represents in magnitude and sense the angle of heel for a selected type of sailing craft under the wind and boom position conditions simulated. Fig. 1 shows an L-shaped member 1 pivoted at 2 in response to rod 3 sliding in support 4 by actuator 5 controlled by a transmitter (not shown) responsive to the angle of deviation of the boom from its position when freely responsive to the simulated wind. A slotted link 6 pivoted at 7 on one leg of the L-shaped member has its free end slotted at 8 to engage pin 9 carried by nut 10 slidable by screwed spindle 11 rotatable by actuator 12 responsive to simulated wind velocity, and further link 13 is pivoted at 14 to the slotted end of link 6 so that the pivots 14 and 7 are spaced equally to pivots 2 and 7. The further link is also pivoted at 15 to rod 16 sliding in a support 17, so that the pivots 14 and 15 are spaced equally to pivots 7 and 14, and the axial movement of rod 16 is a function of wind speed and boom deviation. Rod 16 is pivoted at 18 to a link 19 symmetrically pivoted about 20 and pivoted at 22 at its free end to a T-member having an extension retained by tension spring 27 an arm with a cupped end engaging a ball headed spindle screwed through a support 26, and rotatable by actuator 25 to move axially in response to simulated wind direction relatively to the fore-and-aft axis of the craft. A further link 28 pivoted to the T- member at 29 at the foot of its arm is pivoted at its free end 30 to rod 31 axially movable in guide 32 to operate transmitter 33, e.g. a control valve or electric switching circuit for an hydraulic or electric servo mechanism actuating the heeling motion of a hull pivoted for heel about a fore-and-aft axis and rotation about a vertical axis (Fig. 3, not shown). A differential gear receives an input from the simulator hull and another from the heel actuator mechanism; the output error signal being utilized to control the hydraulic or electric circuit so that actuation ceases on assumption of the correct heel angle corresponding to the supplied simulated wind direction, wind velocity, and boom direction fed in; the error signal then being reduced to zero. In a modification (Fig. 2) a reversible hydraulic actuator 47 rotates the mast of the simulator hull (Fig. 3, not shown) with the boom rigidly attached thereto at an angular position applied to an input of differential 43, also receiving input from a magslip circuit 42, 420 representing simulated wind direction referred to the fore-and-aft line, from a device of the kind described in Specification 1,165,673, and the differential output drives potentiometer 44 over electric clutch/brake unit 413, 415. The potentiometer is energized from a D.C. source shunted by centre tapped voltage divider 416a, whose midpoint is returned to the midpoint of a centre tapped voltage divider 416b in parallel with a further centre tapped voltage divider whose centre tap is connected to an input of a two component transistorized D.C. amplifier 46. When potentiometer 44 is centralized the signal supplied to the opposite input of the D.C. amplifier is identical with that from the voltage divider, and the outputs of its components are applied in opposition to an electrically controlled hydraulic control valve 48 operating in response to the sense and magnitude of the output unbalance. Hydrualic actuator 47 rotates the mast and boom until balance is restored over differential 43 and potentiometer 44. At limits of travel, microswitches release clutch 413, apply brake 415, close solenoid valve 418a, and, via switch unit 419b, open valve 418b in such sense as to retain the boom in position. When wind direction is such as to move the boom to another position, microswitch 411 driven from differential 43 by cam 43c geared thereto closes the clutch 413 and releases the brake 415 so that valve 418b closes 418a opens, and the boom is driven into a corresponding position in response to potentiometer 44 and amplifier 46. A gybe (in which the boom is rapidly moved from one side of the craft to the other as the simulated wind carries aft) is simulated by operation of valve 418b by switch unit 419a, magslip coupled to the wind resolver described in Specification 1,165,673 to apply hydraulic pressure to actuator 47, transferring the boom until microswitch 425 operates to arrest hydraulic feed but to maintain pressure to hold the boom in position. Actuator 47 is bearing mounted (Fig. 3, not shown) and its casing carries pinion 421 engaging a pair of spring loaded racks such as 422, 423, enabling the pupil to position the boom by means of the main sheet and rotate the actuator body against spring loading. Pinion 421 engages a further rack 425 and a pinion 424 rotatable in accordance with the deflection of the boom from its natural position along the direction of the simulated wind, to adjust potentiometer 51 in series with variable resistance 53, 54, set to represent wind direction relative to the fore-andaft line of the hull and the wind speed respectively. Resistance 53 may be linked to correspond to wind direction variations referred to the fore-and-aft line as the hull rotates about its vertical axis; e.g. by the device described in Specification 1,165,673; while resistance 54 may be programmed to simulate gusts, and in extreme position for zero wind may be switched out of circuit. The output of potentiometer 51 is connected to the input of one part of a two component transistorized D.C. amplifier 56, whose other input is derived from a further potentiometer 52 representing heel angle; the potentiometer outputs diverging from neutral in either sense for port or starboard boom position or heel. The amplifier outputs are combined in opposition to operate an electrohydraulic valve 57 having controlled outputs to hydraulic heeling actuator 58 geared to the hull (Fig. 3, not shown) and to potentiometer 52; response being moderated by electrolytic capacitors shunting the amplifier output and the energization of potentiometer 51. Thus the heel control signal applied to the actuator is a function of the boom position as controlled by the main sheet, in combination with the wind direction and wind speed as set in manually. Potentiometer 52 and potentiometer 51 in series with variable resistances 53, 54 are energized from a D.C. source in shunt with centre tapped resistance potential dividers 51a, 51b, 52a, 52b; the centre taps being commoned and one end of the former divider being earthed. The computer may be of the fluid logic type, and the simulator may comprise (Fig. 3, not shown) a hull rotatable about a vertical axis by a tiller and rudder linked through a geared turning motor, and also rotatable for heel about a horizontal axis by a geared heel motor responsive to the control described. The boom is controlled by a geared motor positioned within the hull. Specification 1,126,351 is also referredto.