iitsii is a hexapod kit that uses 18 servo motors. It is powered by the Bigfoot™ Inverse Kinematics Engine. It's designed to be a fun, affordable and easy to use platform for students and hobbyists to learn about robotics.
The Bigfoot™ Inverse Kinematics Engine handles all the complex math calculations necessary for controlling multi-legged walking robots. All computations are safely hidden from the user in the form of a black box. This means that the user only has to send short and simple commands to the robot (for example, instructing it to walk forward at a desired speed) and the engine will automatically take care of all the details, including inverse kinematics, leg trajectory planning, leg gait coordination, motor control, etc. This makes it quite easy even for absolute beginners to play with advanced robotics.
The frame of the hexapod is made entirely of PCB.
Commands are sent and received via wireless XBee. Optionally, you can connect your own serial communication method with the provided Rx/Tx pins.
You can choose between pre-programming your own sequences or directly controlling the robot in real time with the Robugtix™ Controller.
NOTE: Batteries are not included. Requires at minimum one single 4.8V NiMH rechargeable battery pack. Optionally, 2 battery packs can be simultaneously connected instead, if you wish to separately power the microcontroller and the servo motors. Doing so will help increase the battery performance. The secondary battery which powers the microcontroller can be either a single 3.6V or 4.8V NiMH battery pack. Complete details regarding power supply requirements can be downloaded below.
The Robugtix™ Controller and wireless XBee modules are not included in this kit. These are highly recommended items to include along with the purchase of this kit since it is the easiest and most convenient way to communicate with the robot.
Posted by Lucas Wells on 12th Sep 2013
Impressive Little Hexapod with Much to Offer
Here’s a small Hexapod that will be sure to provide you with plenty of entertainment and give you some impressive tools at the same time.
I’m going to start my review with some pros and cons and go into more detail afterwards.
-The inverse kinematics are impressive. It does everything I would expect a hexapod to do.
-I enjoy the smooth transitions between gaits, very nice.
-The servos seem accurate and aren’t terribly noisy
-The pieces are very precisely made and fit well together
-Easy enough construction, with a bit of patience
-Had a couple extra parts, such as two extra servos. I like that I have backups.
-The provided hardware is very lacking. Plastic standoffs, plastic rivets, and plastic servo horns.
-Did not receive backups for standoffs, one was stripped on one end
-Precise alignment of the legs is difficult and time consuming, wish I had some sort of jig for this
-The torque in the legs occasionally makes the legs fall off, bring a pair of plies and a screwdriver
-Payload is very light
Construction: This part was actually fairly easy and straight forward, just a bit repetitive. It’s a hexapod, so you have to make six legs of course. Some of the screws are very tiny, so you need to be careful not to lose them. The trickiest part of construction was probably getting all the cables in the right position and plugs. With the legs dangling about, it’s a bit challenging to tell which one goes where. I ended up getting it right the first time, which I was happy about. After you get the legs on, it isn’t really that simple to go in and adjust the plugs again without a good deal of disassembly
The laser cut pieces are very sturdy and precise. I was extremely happy with those. It looks like the entire hexapod is made out of PCB. It works though. The hardware that came with the hexapod I found a bit lacking. The plastic pieces, which included the servo horns, standoffs, and rivets aren’t all that great. A lot of torque goes through the legs while the hexapod is moving. The plastic rivets really like to come undone. I switch them out when they fail and I still get occasional issues. I really wish they were screws or something stronger. The plastic standoffs I didn’t have much issue with except for one which was for a leg, the treads were stripped. This makes it impossible for the leg to be pressure fit appropriately. My solution: zip ties. This works great and the leg holds well now, but I wish I had a back up standoff. The plastic servo horns leave some to be desired too. When I was twisting the body one of the horns got bent out of shape a bit. I was able to push it back, but eventually it’s going to break from stress.
Something else that will stress the hexapod is the weight of your battery packs. Initially I tried to use two 4.8v AA 2200 mAh battery packs just to make sure it had plenty of juice. Bad idea. The legs really had to fight the weight and fell off frequently. I later switched it to one 4.8v AA 2200 mAh pack for the servos and a 4.8v AAA 900 mAh pack for the controller which ended up weighing a lot less. It seems to be okay with this load. I plan on charging up my 2/3 AAA pack later to see if I can shave some more weight off and use the AAA size pack for the servos.
The operation itself is very simple. I did get the recommended remote and XBee wireless modules. It works seamlessly. The remote is very nice. It has a total of eight axis (six used for the hexapod, two for menus) and four buttons, since each stick can be pushed down. It really doesn’t take any instruction to move the hexapod around and have a great time. The only instructions you might want to learn is menu navigation.
Finally, all the commands that are built into the controller for the Hexapod are very well documented. I was very happy with this. You can easily put together routines of your own and program them into the controller or whatever other device you’re using. Additionally, there are built in commands for reading an ultrasonic sensor, in which there are solder points for on the hexapod itself. This probably explains the additional servos as you could easily create a pan/tilt with the two and then use the ultrasonic sensor for obstacle avoidance.
Conclusion: If you want an inexpensive hexapod and are willing to spend some time putting it together and occasionally fixing it up, then you’ll have a great time with the Iitsii.