Wednesday, July 28, 2004

the vertical ankle connector can be seen here
Keith Rowell Design

Leg to ankle connector, foot side.
Keith Rowell Design

Tuesday, July 27, 2004


The foot plate I built in IronCad
Keith Rowell Design

Ankle Parts are Hashed Out

Others are showing intrest in joining the team as design drawings get passed around. The "cool factor" of this design is contagious.

Ankle design shows limits of motion.

This is my second attempt at getting vertical movement from the foot lift motion, while keeping the foot horizontal. The hatched parts in this image are the ankle links with the foot in the down position.

The actuator could either be in the foot, close to the ankle, or in the body at the top of the leg, and linked to the ankle "tendon" style...

I love this walker idea. Richard is getting pretty fired up about it, so when you get the details worked out send us the drawings and we’ll start making parts. Could we make a scale version? I mean can the electronics be scaled up or down? This is good stuff.


Friday, July 23, 2004

Gettin Mechie

I turn to the CAD files now to hash out some physical design.

The original from the Star Wars series

A 2D study of the leg positions

I work out a design that uses the Stomper and MiniMecha linkage. This preliminary layout difines some limits to size and motion. Armed with these parameters, I feel confident to move forward.

Tuesday, July 13, 2004

Bob's Code Puts Mojo Through it's Paces.

Bob Baxter writes code for a pic to send Hex code to the Servo Mojo, and we start testing.

Testing the Leg Mockup
Keith Rowell Design

I don't see anything in the datasheet on the max rotation of the servo. I tried a couple of standard Hitec servos. They rotate just over 180 degrees at pulse widths of about 700usec to 2.3msec. Getting anywhere with the time line?

At 04:11 PM 7/11/04 -0400, you wrote:
>this link shows the servo I'm using.
> HiTek
> HS-55
>we probably do need to use expanded mode to get more than 90deg.
> > -----Original Message-----
> > Sent: Sunday, July 11, 2004 3:46 PM
> > Subject: modified Mojo Board software
> >
> > I have modified the code we were working with on Friday to handle wide mode. It seems to be working. I found that if I add a millisecond or two of inter-character delay the comm from the PC to the PIC is much more reliable.
> >
> > In looking at the manual it seems that just going to wide mode doesn't get you motion of greater than 90 degrees. I think you need to use the expanded pulse width mode to accomplish it. If you can send me the datasheet for the servos or let me know the manufacturer and part #, I'll take a look.
> >
> > Bob