Phoenix Gait Engine Question

Lynxmotion Legged Robots
1

Hello all,

So I’m a bit confused in using the gait engine that comes with the phoenix_v20 code. I’m trying to develop a quad gait. To do so I am using the following parameters:

  IF (GaitType = 1) THEN ;Quad gate
  	GaitLegNr(cLR) = 1
   	GaitLegNr(cRF) = 2
   	GaitLegNr(cRR) = 3
   	GaitLegNr(cLF) = 4 
   
   	HalfLiftHeigth = 0       
  	NrLiftedPos = 1
   	TLDivFactor = 4
   	StepsInGait = 4
   	NomGaitSpeed = 150
  ENDIF

If I understand this correctly, the sequence goes Left-Rear, Right-Front, Right-Rear, Left-Front. There is only one leg in the air at a time (NrLiftedPos = 1) and each leg pushes along the ground (TLDivFactor = 4). Since I only have 4 legs, I have selected 4 for StepsInGait.

When I run this gait, the quad’s right-side legs seem to work fine. The left-front leg never moves, but the left-rear leg begins the gait. Only the right-side legs show any horizontal positioning.

Can anyone provide greater clarity on the gait engine, I’ve read through the documentation but I’m a bit stumped.

Thanks in advance,

2

apart from the other things you mention, of which sounds like you have an assembly problem, or pin assignment, this might work better for you as a quad gait.

[code]
IF (GaitType = ?) THEN ;Wave 24 steps
GaitLegNr(cLR) = 1
GaitLegNr(cRF) = 21
GaitLegNr(cRR) = 13
GaitLegNr(cLF) = 9

NrLiftedPos = 3
HalfLiftHeigth = 0
TLDivFactor = 20
StepsInGait = 24
NomGaitSpeed = 100
ENDIF[/code]

also may i point you to here. you will find more info on Hex to quad conversion.
viewtopic.php?f=8&t=1964&start=0

3

Thanks for the reply innerbreed,

No pin issues, or battery issues. Other gaits move all the legs. Thanks for the parameters, however, they don’t seem to make sense for a four legged bot, perhaps 6. I’m trying to understand how the gait engine works; i want to calculate for only four legs.

Based on the linked thread, I’ll let it calculate for a middle leg, however, would like to get some additional clarity on the gait engine. Ultimately I would like to have a purely 4-legged gait.