what you are experiencing is that the harmonics of your bed are too closely matched to the harmonics of your activity. Once the two combine then you can form a standing wave which can shake the house to its very foundations if the amplitude is large enough (I'll leave Mrs Foxie to comment on your 'amplitude')
It's the same effect as marching soldiers on a bridge. Hence the command to 'break step' when a body of troops crosses a bridge. You need to manage the same effect. You therefore need to change either your harmonic or the bed's harmonic.
I'd suggest one of two things. Either:
Replace a couple of the legs of your bed with randomly oscillating bed-leg like devices. They'd need to be about as thick as your wrist, 9-12" in length, ideally rubber or soft plastic (self-dampening), and the important part is that you need to be able to set them to oscillate at different frequencies, so some sort of power and rheostat device. Maybe Mrs Foxie might have something suitable you could use.
Or two: adjust your harmonic at random intervals – start slow, build up speed to the point where you're in danger of coming to a juddering and crashing halt, and then ease back a bit until you've just got it back under control. Then stick at this level for a while until – and here's the key bit – you then need to accelerate right through the frequency where the standing wave forms to a frequency that frankly will leave you a bit sweaty and unable to stand (your legs may even go wobbly at this point). It's maximum heart rate stuff but you won't need to keep it up for much longer. There's no way at this point the harmonic of the bed can match your harmonic and while it may splinter and crack under the effort of trying you're home and dry. No unwanted bed noises, although you may end up with matching his and hers asbos.
