Project introduction: Design a quadruped robot, which looks like the following

B station video link:

Version 1: (bilibili with epilepsy from birth) 18650 battery powered https://www.bilibili.com/video/BV1ra411M7d1

Version 2: (After changing the dog food, the epilepsy was cured) Replacing the model aircraft battery https://www.bilibili.com/video/BV1mt4y1G7aC

In fact, after 3D printing, the assembly is completed like this:

Action demonstration

Project Analysis:

1. Structural part

It is made with reference to the structure of Deng Ge's quadruped robot. The attachment is the latest version of 3D drawings, which can be directly prototyped and produced. The production price is about 200 yuan. Click here for the specific open source link: Deng Ge open source quadruped robot project

2. Circuit part

1. Based on Hongmeng Hi3861 main control, it supports Hongmeng system development. Purchase link

2. The 8-channel servos are managed by the driver chip PCA9685PW. This chip can control up to 16 servos. Use IIC interface to connect with microcontroller.

3. The MPU6050 module reads the angular velocity and gyroscope data to identify the current status of the dog, thereby better controlling the dog's walking.

3. Software part

1. Use Hongmeng development platform for development, the development environment is ubuntu20 Linux environment compilation, and the windows platform serial port burning program

4. Assembly part

1. Accessories procurement:

(1) Thigh connection bearing:

Need to purchase 4pcs. Purchase link

(2) Locking nuts: You must purchase locking nuts for connections, otherwise they will loosen after just a few steps.

Purchase link

(3) Calf tie rod assembly:

Purchase M2X35mm 4pcs purchase link

(4) MG90S steering gear:

Purchase 8pcs purchasing link

(5) MPU6050 module:

Purchase 1pcs purchasing link

(6) Screws: Purchase link

(7) Battery: Purchase link

(8) Remote control: Isn’t it nice to control it without buying WIFI? Purchase link

Schematic design instructions

Lithium battery charging, discharging, boost circuit

PCB design instructions

Software description

Brief description of dog movement algorithm: refer to Pineapple Dog

Algorithm Reference: Deng Ge Quadruped Robot [Tutorial] Deng Ge 0 Basic DIY Quadruped Robot Guide

1. Correct solution to kinematics

• Known: Angle of thigh and calf
  
• Find: foot end coordinates
  

1. Calculation process of forward solution of kinematics

The legs of the robot dog are placed as shown in the figure, and a coordinate system is drawn on the plane where the legs are located, as shown in the figure below. The angle formed by the thigh and the x-axis is A1 (the angle of the thigh), and the angle formed by the extension line of the thigh and the calf is A2 (the angle of the calf).

2. Calculation method

3. Rotation Transformation--Refer to Deng Ge’s open source video: Rotation Transformation

2. Inverse solution of kinematics

• Known: foot end coordinates
  
• Request: Angle of thigh and calf
  
  
  
  
  

Physical display instructions

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Issue not resolved

1. Circuit board design V2.0 version. The current version can only be powered by data lines because the current is too large. The 18650 battery cannot carry 8 servos, and the instantaneous current is about 2A.

It was resolved on July 22. The power supply part was replaced and powered by model aircraft battery.

2. Add mpu6050 module as dog posture verification. The software is being written and has not been completed.

3. It is planned to add the K210 module as a dog head camera for object recognition and object tracking. There is a plan but it has not been implemented yet.

4. The circuit boards are integrated and now spliced ​​for various circuit boards.

Demo video