For making the jolt waveform programmable, I have chosen a sine-wave with
exponential decay.
Sine polarity, begin amplitude, sine period, and decay can be set before the
effect begins. The effect can be added to both roll and pitch axis,
each with independent parameters.
Triggering flight parameter is the wheels-on-ground bit. Aircraft bank just before touch-down will determine the sine polarity.
The trial program is shown below.
20 ON ERROR GOTO 140
30 CLOSE #1
40 OPEN "com1:9600,n,8" FOR RANDOM AS #1
50 A$=""
55 ON ERROR GOTO 50
60 LINE INPUT#1, A$
70 P$=mid$(A$,3,2)
80 R$=mid$(A$,5,2)
82 D$=right$(A$,2)
85 P=INSTR("123456789ABCDEF",right$(P$,1))+16*INSTR("123456789ABCDEF",left$(P$,1))
86 R=INSTR("123456789ABCDEF",right$(R$,1))+16*INSTR("123456789ABCDEF",left$(R$,1))
87 D=INSTR("123456789ABCDEF",right$(D$,1))+16*INSTR("123456789ABCDEF",left$(D$,1))
90 IF D AND 2 GOTO 95 'check wheels-on-ground bit
91 AR=20:AP=30:N=-1:Rout=0:Pout=0: 'AR is max roll sine amplitude, AP
is max pitch sine amplitude
92 IF R>127 then RPOL=-1 else RPOL=1 'set roll sine polarity
depending on bank
93 GOTO 120
95 ER=1.4:TR=1:EP=1.8:TP=2:NR=20 'ER is roll exponential, TR is
roll sine period, EP is pitch exponential, TP is pitch sine period, NR is
total number of cycles (20 is about 1 second)
100 IF N>NR then Rout=0:Pout=0:GOTO 120 'finish sequence after N
cycles
105 N=N+1
110 Rout=INT(RPOL*AR*(sin(N*3.14/(2*TR)))) 'Roll sine wave with
polarity
111 Pout=INT(AP*(sin(N*3.14/(2*TP)))) 'Pitch sine wave
112 PRINT N;AR;AP;Rout;Pout
115 AR=AR/ER 'Roll sine amplitude decay
116 AP=AP/EP 'Pitch sine amplitude decay
120 DAC1=127+Pout
121 DAC2=127+Rout
123 IF DAC1>255 or DAC1<0 then goto 127
124 OUT 888,DAC1
125 OUT 890,3
126 OUT 890,11
127 IF DAC2>255 or DAC2<0 then goto 131
128 OUT 888,DAC2
129 OUT 890,9
130 OUT 890,11
131 GOTO 50
Left wheel first
Right wheel first
Above graphs show the DAC outputs at touchdown with above program::
Top waveform is roll axis, bottom is pitch axis
>>> A flight video of the above motion cue can be seen here. The video shows a lousy landing with right-wheel first, bounce and then left-wheel first.
The effect feels pretty good. Most important is the roll jolt. Pitch will just add a little bump upwards (since you are sitting behind the rotation point, upward bump = pitch down), probably not really needed.