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Subject: 
Re: SSClagorpion
Newsgroups: 
lugnet.technic
Date: 
Sat, 8 May 2004 15:59:47 GMT
Viewed: 
17558 times
  
In lugnet.technic, Steve Hassenplug wrote:
> In lugnet.technic, Kevin L. Clague wrote:
> > My first thought is to forgo sideways walking.
> > 
> > 
> ...
> > This means that it would be able to walk in six directions, instead of 4, at the
> > cost of 8 switches. ...
> > 
> > This costs us 8 more pistons, and 8 more switches.
> 
> 
> 
> How about if you make up a proposal?  Actually, two.
> 
> First, get out your pen, paper, calculator, sliderule, and excel spreadsheet,
> and figure out how many pistons & switches are required.

I used my brain.....

> 
> I'd suggest two options:
> A) No Sideways.  Forward/back, turn in place R or L

leg_cost = 2 pistons, 4 switches

n_legs = 8

legs_cost = 8(2 pistons, 4 switches)
          = 16 pistons, 32 switches

timing_cost = 2 pistons, 2 switches

reverse_cost = 8 switches

turn_cost = 8 switches

total_cost = legs_cost + timing_cost + reverse_cost + turn_cost =
    16 pistons + 32 switches +
    2 pistons  +  2 switches +
                  8 switches +
                  8 switches
  = 18 pistons + 50 switches

> B) Straight sideways.  two pistons/LEG SWEEP.

leg_cost = 4 pistons + 8 switches

n_legs = 8

legs_cost = 8(4 pistons, 8 switches)
          = 32 + 64

timing_cost = 2 pistons + 2 switches

reverse_cost = 8 switches

turn_cost = 8 switches

half_sweep_cost = 8 switches

sideways_step_cost = 16 switches

total_cost = legs_cost + timing_cost + reverse_cost + turn_cost +
half_sweep_cost + sideways_step_cost
           = 32 pistons + 64 switches +
              2 pistons +  2 switches +
                           8 switches +
                           8 switches +
                           8 switches +
                          16 switches
           = 34 pistons + 106 switches

> 
> Count EVERYTHING.  What is the grand total?
> 
> While I think walking sideways would be very cool, I also think it will add a
> ton of complexity to this thing.  In addition to the set of walking
> switches/pistons, we'd need to have switches to set the legs to "out" when it's
> not walking sideways, and we'd need switches to set the legs to "middle" when
> not walking forward/back.

It looks like sideways makes it more than twice the cost, both in pistons and
switches.

> 
> I'm really starting to think it will top 100 switches.

You are correct.

> 
> Steve

C) staggered sideways walking

leg_cost = 3 pistons + 6 switches

n_legs = 8

legs_cost = 8(3 pistons, 6 switches)
          = 24 pistons + 48 switches

timing_cost = 2 pistons + 2 switches

reverse_cost = 8 switches

turn_cost = 8 switches

sideways_hip_change = 8 switches
sideways_out_force  = 8 switches
hip_sidways_swap    = 8 switches

sideways_step_cost = sideways_hip_change + sideways_force_out +
hip_sideways_swap
                   = 8 switches + 8 switches + 8 switches
                   = 24 switches

total_cost = legs_cost + timing_cost + reverse_cost + turn_cost +
half_sweep_cost + sideways_step_cost
           = 24 pistons + 48 switches +
              2 pistons +  2 switches +
                           8 switches +
                           8 switches +
                          24 switches
           = 24 pistons + 90 switches

In summary:
   A) Forwards/backwards/turning     18 pistons and 52 switches
   B) +sideways walking              34 pistons and 106 switches
   C) six direction walking          24 pistons and 90 switches

I'm fine with (*just* :^) forwards/backards/turning at 18 pistons and 52
switches, and deferring sideways walking to a future model.

As a point of reference, PhD (my most advanced hexapod) has 14 pistons and 76
switches, and will be able to walk 6 directions and turn.  It can do all that
because the body is radially symmetric.  The down side is that the legs *do*
cause stress on each other.

Kevin



Message has 1 Reply:
  Re: SSClagorpion
 
(...) hmm. I didn't think about doing that. :) (...) Does that include the sideways_out_force? It may be about 8 switches short. But I don't think that matters. (...) Yes. I'm fine with that, also. Eric? (...) Looking at the totals on top, I think (...) (22 years ago, 9-May-04, to lugnet.technic)

Message is in Reply To:
  Re: SSClagorpion
 
(...) ... (...) ... (...) How about if you make up a proposal? Actually, two. First, get out your pen, paper, calculator, sliderule, and excel spreadsheet, and figure out how many pistons & switches are required. I'd suggest two options: A) No (...) (22 years ago, 8-May-04, to lugnet.technic)

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