what is the angle of rotation of lynxmotion hexapods and it’s payload capacity
and everything needed for control system design to model the system correctly
I’m asking this because i’am considering buying one for my undergrad final year project for AI engineering (CV and Robotics)
Please respond , and thank you in advance
@Saboteur20 Welcome to the RobotShop Community. You can see all Hexapods here:
http://www.lynxmotion.com/c-3-hexapods.aspx
There are currently many hexapods, in various different kits, with different configurations.
- “Hardware only” means the kit only includes the frame, brackets and hardware
- “No electronics” means the kit includes “hardware only” as well as servos
- “BotBoarduino / SSC-32U” includes all hardware, servos, MCU and servo controller
None of the robots include a 6V battery, charger or Lynxmotion PS2 controller / receiver.
Note that all hexapod kits, when used with the BotBoarduino and SSC-32U are meant to be used with the Phoenix sample code. The A-Pod however is different in that it has a “head” and “tail”, and the previous code has not been ported to Arduino.
Q1) what is the angle of rotation of lynxmotion hexapods and it’s payload capacity
All servos can rotate 180 degrees, but the mechanical structure of almost all hexapods physically impedes rotation. You would need to redraw the parts and assembly in CAD to determine the actual angle of rotation for each joint. Note too that servos need to be calibrated to specific angles before proceeding with walking, so in many cases the servo’ may reach its maximum angle before any physical limitation.
Regarding payload capacity, it’s a very difficult number to give because:
- Each robot is configured differently, with different brackets, dimensions etc.
- The walking gait and leg configuration have a big impact on the payload
- The choice of battery and electronics need to be taken into consideration
To be safe, you should be able to add around 500g beyond the suggested battery, with the exceptions of the Phoenix and A-Pod.
You may also want to consider participating in the SES V2 hexapod project found here:
https://community.robotshop.com/forum/t/lynxmotion-ses-v2-legged-robots/62511/260
The “core” team is comprised of all three original Lynxmotion designers, Kurte, Xan and Zenta. This hexapod (still a work in progress) will become the next generation of Lynxmotion hexapods and makes use of the Lynxmotion smart servos. Currently (July 2020), the objective is to first port the Phoenix code to a Teensy (Arduino compatible), and subsequently create ROS code for a Raspberry Pi (where you might be able to more easily integrate computer vision).
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thank you very much for your fast and on-point response .
I would also like to know if it’s possible to add sensors and a lens or a cam on any of the models?
and about the payload , can the phoenix endure a maximum of 150 kg to 250 kg approx ?
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First question, can you confirm the right units? You wrote 150Kg to 250Kg (as opposed to grams).
Second regarding adding vision sensors, there are no specific mounts for cameras, so you will need to create your own. You can either 3D print, or use a Lynxmotion SES bracket and add a custom plate.
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Sorry I meant grams .
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The Phoenix can support 250g without issue, beyond the main battery and electronics. However, it can support less than the other hexapods since the legs are only support by the output shaft of each of the servos. The A-Pod is also already having to support the head, mandibles and tail, meaning its additional payload is also reduced.
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can the A-Pod support a camera mount ?
is it possible to use a raspberry PI instead of using an arduino?
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Can the A-Pod support a camera mount ?
A small action / sports camera mounted to the body? Certainly. A large DSLR, unlikely.
Is it possible to use a raspberry PI instead of using an arduino?
The electrical connections are fairly easy, but there is no sample code for the Pi.
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what kind of servo motors can be used with the A-pod , especially with the mandible ?
is it possible not to attach the tail ?
does the hard-ware version comes with the wiring ?
what extra hard-ware should be bought , and how many servos ( I approximated 20) ?
how to manage the linkage between this amount of servos with the rasp ?
Q1) what kind of servo motors can be used with the A-pod , especially with the mandible ?
Only Hitec standard servos can be used (HS-322, 422, 485, 645, etc.) which all have the same physical dimensions. The knee and shoulder servos in each leg need to be at least 645, while lower torque areas like the mandibles can be 422. Whenever possible, we suggest using all 645 servos.
Q2) is it possible not to attach the tail ?
Yes, you can mount the main controller in the body (step 12):
http://www.lynxmotion.com/images/html/build181.htm
Attaching the tail (or not) is step 9 here:
http://www.lynxmotion.com/images/html/build182.htm
If you don’t mount the tail, but still keep the mandibles, you will also have to compensate for the offset center of body, which is moved towards the front of the robot.
Q3) does the hardware version comes with the wiring ?
It includes the servo extension cables, and wiring harness with Tamiya battery connector.
Q4) what extra hardware should be bought, and how many servos ( I approximated 20) ?
There are 25 servos in the A-Pod (three per leg, 7 servos for the head and tail).
Q5) how to manage the linkage between this amount of servos with the rasp ?
Complete guide can be found here: http://www.lynxmotion.com/driver.aspx?Topic=assem04
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You may want to contact the author of this post since they claimed to have an hexapod that is similar working with the RPi.
I imagine you’d want to use a SSC-32U as normal. The RPi certainly cannot handle any servomotors directly since it has a limited amount of GPIOs and they are at the wrong voltage level. Also, the RPi (and similar boards) typically are very sensitive to voltage/current issues and can easily be damaged. The lesson here: never connect the RPi to anything directly unless you are 150% sure it won’t damage it (or you can afford or not care about having to replace it).
I hope this info helps!
Sincerely,
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thank you very much .
to your experience , how can i safely power the RPi and the servos to avoid damage ?
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It depends on if you want one or two power supplies. The servos need 6V, while the Pi takes a regulated 5V via USB. You can use an external 5V battery backup for the Pi, or a voltage regulator which converts 6V to 5V and connect the right pins from a USB cable to the output. This is a good question which was resolved for the LSS system using the LSS-5VR, though this is intended for at least 6.5V input.
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