In the spare moments between work today, I’ve been thinking about rough design parameters for the CF Walker biped. To get some initial numbers, I started with the fact that it has to complete a 10k walk. Jim and I decided on 4 hours as being a reasonable target to complete the walk (it takes the average human about 2 hours to walk 10k). To travel 10k in 4 hours, the robot will have to average 2.5kph or .69 meters per second. If the robot has a stride of 1 meter, it would need to complete one step every 1.45 seconds. I think a 1 meter stride is possible – Jim is thinking of something more like a foot (about 1/3 of meter).
Due to the time constraints, we’re unlikely to be able to do anything that requires dynamic balancing, which limits the design further. We still have several ideas for making it work but haven’t come up with one that we feel is a sure thing yet. Originally we were thinking we’d just scale up Eric’s Little Toddler since it doesn’t require dynamic balancing, already works, and they’ve mastered the software algorithms needed to turn it smoothly. It presents two problems for us though: 1. It can’t handle the non-flat surfaces that we’re pretty sure CF Walker will run into such as handicap ramps, curbs, and possibly pot-holes. 2. The gait of the current design is much too slow.
The speed issue can be partially dealt with at the cost of higher power consumption. But with a limited payload capacity, that means more stops to rest (recharge from the solar array), so we’ll need to find the best balance between speed and efficiency. We’ve also got a possible trick or two to tackle the problem of curbs but at the cost of giving the robot a very non-human gait.